Solar Power Satellites

Home , Exosphere, Mesosphere, Mohave Power Station, Peter Glaser

August 1981

NTIS order #PB82-108846 Library of Congress Catalog Card Number 81-600129

For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402 Foreword

The energy difficulties the Nation has faced over the past decade have given rise to an increased awareness of the potential long-term, inexhaustible, or renewable energy technologies. This assessment responds to a request by the House Committee on Science and Technology for an evaluation of the energy potential of one of the most ambitious and long-term of these technologies, the solar power satellite (SPS). In assessing SPS, OTA has taken into account the preliminary nature of SPS technology by comparing four alternative SPS systems across a broad range of issues: their technical characteristics, long-term energy supply potential, international and military implications, environmental impacts, and institutional effects. The SPS options are also compared to potentially competitive future energy technologies in order to identify how choices among them might be made. In addition, OTA developed a set of Federal research and funding options to address the central questions and uncertainties identified in the report. We were greatly aided by the advice of the SPS advisory panel, as well as by the participants in three specialized workshops: one on alternative SPS systems, one on public opinion, and another on competing energy supply technologies. The contributions of a number of contractors, who provided important analyses, and of numerous individuals who gave generously of their time and knowledge, are gratefully appreciated.

Director

. . . Ill Solar Power Satellites Advisory Panel

John P. Schaefer, Chairman University of Arizona Paul Craig Jerry Grey John J. Sheehan University of California American Institute of Aeronautics United Steelworkers of America S. David Freeman and Astronautics Graham SiegeI Tennessee Valley Authority Grant Hansen Tennessee Valley Authority Eilene Galloway SDC Corp. Robert Uhrig Consultant Russell Hensley Florida Power & Light Karl Gawell Aetna Life & Casualty Frank von Hippel Solar Energy Research Institute Maureen Lamb Princeton University Peter G laser Consultant Charles Warren Arthur D. Little, Inc. J. C. Randolph Attorney University of Indiana

Workshop on Technical Options

John W. Freeman, Jr., Chairman Joe G. Foreman John D. G. Rather Rice University Naval Research Laboratories The B.D.M. Corp. Kenneth Billman Jerry Grey Fred Sterzer Electric Power Research Institute American Institute of Aeronautics RCA Laboratories Hubert P. Davis and Astronautics Frank von Hippel Eagle Engineering Abraham Hertz berg Princeton University Henry M. Foley University of Washington Gordon Woodcock Colurnbia University Boeing Aerospace Co

Workshop on SPS Public Opinion Issues

Ken Bossong Leonard David Skip Laitner Citizens Energy Project National Space Institute Community Action Research Croup Ben Bova Chris E If ring of Iowa, Inc. OMNI Office of Technology Assessment Maureen Lamb Clifflyn Bromling Joe Foreman Consultant Bromling and Associates Naval Research Laboratories Jenifer Robinson Mike Casper Jerry Grey Office of Technology Assessment Carlton College American Institute of Aeronautics Louis Slesin Earl Cook and Astronautics Natural Resources Defense Texas A&M Council, Inc.

Workshop on Energy Context of Solar Power Satellites

Clark Bullard, Chairman Peter Drummond William Metz University of Illinois McDonnel-Douglas Astronautics Consultant Charles Baker Lessly Goudarzi David Morris Argonne National Laboratory International Energy Associates, Institute for Local Self Reliance Piet Bos Limited James Moyer Electric Power Research Institute Kenneth Hub Southern California Edison Glen Brandvold Argonne National Laboratory Larry Ruff Sandia National Laboratory Jerry Karaganis Brook haven National Laboratory Clifflyn Bromling Edison Electric Institute Frank von Hippel Bromling & Associates John Lamarsh Princeton University Paul Craig Polytechnic Institute of New York Gordon Woodcock University of California Kenneth Ling Boeing Aerospace Co. Applied Solar Energy Corp.

iv Solar Power Satellites Project Staff

Lionel S. Johns, Assistant Director, OTA Energy, Materials, and International Security Division

Richard E. Rowberg, Energy Program Manager

David Claridge, Project Director (until January 1980) Ray A. Williamson, Project Director (from January 1980) Stefi Weisburd Adam Wasserman

Administrative Staff Marian Grochowski Lisa Jacobson Lillian Quigg Edna Saunders Yvonne White

Contributors Clifflyn Bromling Alan Crane Arlene Maclin William Metz

Contractors and Consultants Eric Drexler International Energy Associates, Ltd. John Furber David Morris Mark Gersovitz Institute for Local Self Reliance Princeton University Barry Smernoff Jerry Grey Smernoff & Associates

OTA Publishing Staff

John C. Holmes, Publishing Officer John Bergling Kathie S. Boss Debra M. Datcher Joe Henson Acknowledgments

OTA thanks the following people who took time to provide information or to review part or all of the study. Martin Abromavage, Argonne National Laboratory Ernest L. Morrison, National Telecommunications Edwin Beatrice, Letterman Army Institute of and Information Administration Research Fred Osborne, Sunsat Energy Council Richard Beverly and William Brown, Raytheon Steven Plotkin, Office of Technology Assessment Tom Bull, Office of Technology Assessment John Richardson, National Academy of Sciences Daniel F. Cahill, U.S. Environmental Protection Michael Riches, U.S. Department of Energy Agency Donald Rote, Argonne National Laboratory Don Calahan, National Aeronautics and Space Charles Rush, National Telecommunications and Administration Information Administration Stephen Cheston, Georgetown University Richard Santopietro, U.S. Department of Energy Stephen Cleary, Mfedical College of Virginia Carl Schwenk, National Aeronautics and Space P. Czerski, National Research Institute of Mother Administration and Child, Poland Richard Setlow, Brookhaven National Laboratory Steven Doyle, Office of Technology Assessment Charlotte Silverman, U.S. Public Health Service Lewis Duncan, Los Alamos Scientific Laboratory David Sliney, U.S. Army Environment/ Hygiene William Erickson, University of Mary/and Agency Harold A. Feiveson, Woodrow Wilson School, Marcia Smith, Congressional/ Research Service Princeton University Gerald Stokes, Pacific Northwest Laboratory Zorach Glaser, Bureau of Radiological Health A.R. Thompson, National Radio Astronomy Anita Harlan, L-5 Society Observatory John Hooper, Sierra Club Kosta Tsipas, Massachusetts Institute’ of Wayne Jones, Lockheed Corp. Technology Don Justesen, Veterans Administration Paul Tyler, Armed Forces Radiological Research Fred Koomanoff, U.S. Department of Energy Institute John Logsdon, George Washington University A.R. Valentine, Argonne National Laboratory Simon V. Manson, National Aeronautics and Peter Vajk, Science Applications, Inc. Space Administration Margaret White, Lawrence Berkeley Laboratory Richard Marsten, Office of Technology John Zinn, Los Alamos Scientific Laboratory Assessment Contents

Chapter Page 1. Summary...... 3 2. Introduction ...... 17 3. Issues and Find ngs ...... 23 4. Policy Options...... 55 5. Alternative Systems for SPS ...... 65 6. SPS inContext...... 101 7. The International Implications of Solar Power Satellites ...... 145 8. Environment and Health...... 179 9. Institutional Issues ...... 227

A. Alternatives to the Reference System Subsystems ...... , ...... 265 B. Decentralized Photo voltaic Model ...... 269 c. Global Energy Demand Forecasts ...... 271 D. Environment and Health ...... 275 E. Examples of international Cooperation ...... 289

Acronyms, Abbreviations, and Glossary ...... 293 Chapter 1 Contents

Page Current Status ...... 3 Energy Context ...... 5 International and Military Imp ications...... 7 Systems and Costs...... 7 Public Issues...... 10 Environment and Health ...... 10 Space Context...... 14

LIST OF TABLES

Page Characterization of Four Alternative SPS Systems...... 9 Summaryof SPS Environmental Impacts ...... 12 The solar power satellite (SPS) concepts en- ● Mirror transmission. Orbiting mirrors vision using the constant availability of sun- would reflect sunlight directly to central light in space to generate baseload electricity locations on Earth. Terrestrial solar re- on Earth. Orbiting satellites would collect ceivers would convert the resulting 24- solar energy and beam it to Earth where it hour illumination to electricity. would be converted to electricity. Three major Since SPS would be a major future energy alternative systems have been suggested. system with diverse potential impacts and im- ● Microwave transmission. Solar radiation placations, this assessment of SPS technology would be collected in space and con- is interdisciplinary. It includes the study of SPS verted to microwaves. Microwave energy interactions with society, the environment, the would be beamed to a receiving antenna economy, and other energy systems. in addi- on Earth where it would be converted to tion, because space is an international realm electricity. and energy is a global need, this assessment Laser transmission. Solar radiation would also undertakes a broad look at the interna- be collected in space and converted to in- tional aspects of SPS. frared laser radiation. The lasers would beam power to an Earth receiver.

CURRENT STATUS

Too little is currently known about the techni- designate an agency to track generic research cal, economic, and environmental aspects of SPS which is applicable to SPS, to review trends in to make a sound decision whether to proceed electricity demand, and to monitor the prog- with its development and deployment. I n addi- ress of other electric supply technologies. Such tion, without further research an SPS demon- a mechanism could provide the basis for peri- stration or systems-engineering verification odic assessment of whether to begin an SPS re- program would be a high-risk venture. An SPS search program. Information relevant to SPS research program could ultimately assure an ade- could be derived from other research pro- quate information base for these decisions. How- grams, microwave bioeffects, space transpor- ever, the urgency of any proposed research ef- tation, laser, and photovoltaic development fort depends strongly on the perception of fu- appear to be the most critical technical issues. ture electricity demand, the variety and cost of However, it is unlikely that such “generic” supply, and the estimated speed with which research programs by themselves would ade- the major technical and environmental uncer- quately answer all of the high-priority ques- tainties associated with the SPS concept can tions on which SPS development decisions de- be resolved. For instance, if future demand pend growth is expected to be low it may not be nec- If a dedicated SPS research effort is started essary to initiate a specific SPS research pro- now, the level of effort chosen would, to a gram at this time, especially if more conven- large degree, determine the time it takes to ob- tional electric-generating technologies remain tain the information needed for a development acceptable. If this is not the case or if demand decision. An effort set at $5 million to $10 growth is expected to be high, SPS might be milIion per year could be sufficient to gather needed early in the 21st century, and a timely the minimum necessary information while min- start of a research effort would be justified. imizing the risk of insufficient or untimely in- Should it be decided not to start a dedicated formation. A $20 million to $30 million per SPS research effort now, it may be desirable to year effort could gain the maximum necessary

4 ● Solar Power Satellites

Photo credit: National Aeronautics and Space Administration Microwave concept

Photo credit: Painting by Frank G. Ellis, Lockheed Missiles and Space Co.

Laser concept

Photo credit: National Aeronaut/es and Space Administration search program is instituted, it should investigate those areas most critical to SPS economic, technical, and environmental feasibility Particular attention should be given to studying and comparing the various technical alternatives; but the feasibility of SPS also ultimately depends on its social, political, and institutional viability. Thus, a research program should continue to explore these aspects of SPS devel- Mirrored concept opment and deployment as well. The following are the major stages such a program wouId SOURCE: K. W. Billman, “Space Orbiting Light Augmentation Reflector Energy System: A Look at Alternative Systems,” SPS Program Review, have to go through: June 1979. SPS Program Steps information at the earliest possible time. It Concept feasibility stages Development stages reduces the risk of not generating enough in- Basic research Systems engineering formation in time to make an adequate devel- Component testing Demonstration satellite opment decision. Whatever the level, if a re- Concept definition Deployment Ch. 1—Summary ● 5

ENERGY CONTEXT

Even if it were needed and work began now, satisfy the entire domestic electricity require- a commercial SPS is unlikely to be available ment for demands totaling 20 Qe (2.5 times before 2005-15 because of the many uncertain- current level) or less in 2030. If demand is ties and the long Ieadtime needed for testing and higher than 20 Qe, then presumably one or demonstration. Therefore, SPS could not be ex- more of the following, SPS, breeders, and/or pected to constitute a significant part of elec- fusion will be needed. Electricity demand will tricity supply before 2015-25. By that time, the be strongly affected by the degree that effi- United States will be importing very little cient technologies for using electricity can be foreign oil. Consequently, SPS cannot reduce our developed. Such technologies can have the ef- dependence on imported oil in this century. fect of lowering the overall cost of electricity However, if efficient electric vehicles or other compared to competing energy forms. electric end-use technologies are developed by If generation from coal on a large scale about 2010, electricity from SPS or other proves to be unacceptable, domestic electrical sources could substitute for synthetic liquid consumption of 8 Qe or less could still be met fuels generated from coal or biomass. by nuclear, geothermal, and terrestrial solar Along with other electric generating technol- (central pIant and onsite) technology. For de- ogies, SPS has the potential to supply several mands up to about 20 Qe, SPS could compete hundred gigawatts of baseload electrical with terrestrial solar, breeders, and/or fusion power to the U.S. grid by the mid-21st century. for a share of the centralized baseload market. However, the ultimate need for SPS and its If electricity demand exceeds 20 Qe, it will be rate of development wiII depend on the rate of difficult to satisfy that demand without vig- increase in demand for electricity, and the orous development of al I renewable or inex- ability of other energy supply options to meet haustible forms of generating capacity. For ultimate demand more competitively. SPS these higher demand levels, SPS, breeders, and would be needed most if coal and/or convent- fusion could all share in supplying U.S. elec- ional nuclear options are constrained and if de- tricity needs. A 30 Qe (3.8 times current con- mand for electricity is high. sumption) total demand wouId create a market potential for up to 6 Qe of SPS-delivered ener- An aggressive terrestrial solar and conservation program that could lead to an electricity gy (225,000-Mw-installed generating capacity at 90-percent capacity factor). * demand level of only 8 Quads electric (Qe)* in 2030 (equal to current consumption) would Upper Range of Possible SPS Use* * make the development of SPS and other large Electric demand SPS capacity (CW] new centralized generating technologies less in 2030 (Qe] With coal Without coal 75 urgent in the United States. In any event, coal 0 0-30 20.0 0-60 100-200 could continue to fuel the greatest share of 30.0 100-200 100-200 U.S. electrical needs well into the 21st century, provided no barriers to its use become evident. Coal, conventional nuclear, terrestrial solar in *Current U.S. generating capacity is about 600,000 MW. Cur- its many forms, and geothermal usage could rent demand represents about 45 percent of this capacity operating 100 percent of the time, **Coal is used as the swingfuel for our analysis because it has *A Quad is equal to 1 quadrillion Btu. It is equivalent to the the largest resource base of any of the current forms of central- energy contained in 500,000 barrels of oil per day for 1 year, and ized, electric generating technologies It is expected that conven- is also approximately the electric energy produced by a 33,500- tional nuclear would be available but its smaller resource base MW generator running without interruption for a year As used in would prevent it from having the large effect on generation-mix this report, Quads electric (Qe) of demand refer to the energy choices that coal does It is assumed that breeders, which would equivalent of electricity at point of use Primary energy input at greatly extend the nuclear fission resource base, would be com- the generating source of electricity IS somewhat more than three parable to SPS and fusion in terms of its rate of market penetra- times these figures tion (ie, 5 to 10 GW/yr)

6 ● Solar Power Satellties

SPS is designed to provide baseload electric- small increments as needed to meet demand ity. By contrast, except for ocean thermal ener- increases on a local scale. gy conversion, terrestrial solar electrical gen- Even if inexpensive storage is not available, on- eration is intermittent. Because our energy site generating technologies could compete in- future will require a mix of baseload and inter- directly with SPS. Total need for baseload mittent generating technologies, without stor- power will decrease if a significant portion of age capability, terrestrial solar would not com- total electrical demand can be met by a compete directly with SPS. However, the devel- bination of dispersed technologies such as opment of inexpensive storage, if achieved, solar photovoltaics, wind, and biomass at costs could enable terrestrial solar electricity genera- that are competitive with centrally generated tion in all its forms-wind, solar thermal, and electricity. Low demand for centrally gener- solar photovoltaics–to assume some share of ated electricity would consequently reduce baseload capacity.* These technologies are less the need to introduce new, large-scale elec- complex, have fewer uncertainties, and are trical technologies such as SPS, except as considerably nearer to commercial realization replacement capacity. than SPS. Furthermore, they have the flexibility to be introduced into the electrical grid in As an energy option for the first half of the 21st century, the potential electrical output and *The percentage share of baseload capacity which would be uncertainties of SPS are comparable to fusion. feasible for these technologies to assume would depend on their These energy options will proceed along dif- geographical location and the time of year (see ch 6) ferent development paths. Except for a laser system, the basic SPS technologies have been proven technically feasible. Research would be needed to develop low-noise microwave tubes; high-efficiency, low-mass photovoltaics; efficient continuous-wave lasers; low-mass mirrors; and space construction and transportation capabilities. Although the fusion community is confident that fusion is feasible, “energy breakeven, ” the production of more energy than is put into the fusion process, has

Photo credit: EPA-Documerica—Gene Daniels Photo credit: Texas Power & Light Trojan nuclear powerplant on the Columbia River near Prescott, Wash., 1972 Martin Lake electric generating plant in east Texas Ch. l—Summary ● 7 not been achieved. For both SPS and fusion, an cost is high. For fusion, much of the manufac- economic generating plant would still have to turing infrastructure for the balance of plant, be developed and demonstrated. i.e., other than the fusion device itself, is in place. Most of the supportive infrastructure Both energy options are designed to pro- for SPS, including the industrial plants and the duce baseload central station power in units transportation system, would have to be de- from 500 to 5,000 MW. For both, development veloped.

INTERNATIONAL AND MILITARY IMPLICATIONS

There could be important economic and politi- with the Soviet Union could spur a U.S. com- cal advantages to developing SPS as a multi- mitment to SPS. national rather than a unilateral system. These include cooperation in establishing legal and The development of fleets of launch and trans- regulatory norms, shared risk in financing the fer vehicles (for SPS), as well as facilities for living R&D and construction costs, improved pros- and working in space, would enhance this Na- pects for global marketing, and forestalling tion’s military space capabilities. Such equip- fears of economic domination and military ment would give the possessor a large break- use. Although a multinational effort would out potential for rapid deployment of person- face inevitable organizational and political nel and hardware in time of crisis, though for difficulties, the strong potential interest of nonemergency situations the military would energy-poor, non-U. S. participants in increased prefer to use vehicles designed specifically for electrical supplies could help make a multina- military purposes. SPS itself could be used for tional venture more feasible than a unilateral military purposes, such as electronic warfare or one by the United States. GIobal electricity de- providing energy to military units, but is tech- mand may quadruple by 2030, and will be es- nically unsuited to constitute an efficient pecially strong in developing countries. West- weapon. Weapons-use of SPS would be prohib- ern Europe and Japan wouId be likely partners ited by current bilateral and multilateral for a joint project. Depending on the size and treaties. The satellite portion of SPS is vulner- expense of the system used, a number of the able to various methods of attack and interfer- more rapidly developing but less developed ence but the likelihood of its being attacked is countries might also be interested in partici- only SIightly greater than for major terrestrial pating at lower levels of involvement. energy systems. The military effects of SPS will depend largely on the institutional framework The Soviet Union is carrying on an aggres- within which it is developed; international in- sive space program that may give them an involvement would tend to reduce the potential dependent capacity to develop SPS, but little for use of SPS by the military sector, is known about their long-range space or energy plans. Real or perceived competition

SYSTEMS AND COSTS

The optimum SPS system has not been iden- oped to provide a basis for review and analysis tified. A National Aeronautics and Space Ad- but was not intended to represent the best ministration/Department of Energy (NASA/ possible system. An optimum system should be DOE) microwave reference system* was devel- able to deliver power in smaller units (about 1,000 MW or less), use smaller terrestrial receivers, and cost less to develop than the *See chs 3 and 5 for a description of the reference system reference system. Alternative systems may use

lasers or mirrors to transmit solar energy from costs for most improvements to the reference space to Earth. Variants of the reference sys- design, or for alternative systems, are less cer- tem or other completely different systems may tain due to the less developed state of nonref- offer certain improvements; each will need full erence technology. Preliminary studies in- study before choosing a system for develop- dicate that the total reference system costs are ment. likely to be significantly higher. On the other hand, alternative systems may well be cheaper Current overall cost estimates for the SPS and than the reference system. The total costs its major components are highly uncertain. The estimated by NASA include major elements, assessments of up-front costs range from $40 such as space transportation and photovoltaic billion to $100 billion. The most detailed esti- cells, whose development is likely to proceed mates have been made by NASA for the refer- regardless of SPS; these costs should not be ence design. These call for a 22-year invest- charged solely to SPS. With the possible excep- ment of $102.4 bilIion (1977 dolIars) (including tion of fusion, the up-front costs for SPS would transportation and factory investment costs) to be significantly higher than competing base- produce the first 5-GW satellite, with each ad- Ioad electric generating systems. Apportioning ditional satellite costing $11.3 billion. The the various investment costs and management Characterization of Four Alternative SPS Systems

Scale Satellite size 55 km2 18 km2 5 km2 50 km2 Number of satellites 60 (300 GW total) Not projected Not projected 916 (810 GW total) Power/satellite 5,000 MW 1,500 MW 500 Mw 135,000 MW Mass 5 x104 tonnes/satellite; 0.1 kW/kg Less mass than reference/O. 1 kW/kg Less mass than reference/O.05 kW/kg 2 x 105 tonnes mirror system 2 kW/kg Land use rectenna site 174 km2 (including buffer) 50 km2 0.6 km2 1,000 km2 x 60=10,440 km2 km2 1,000 MW 35 33 1.2 7.4 Energy Electricity Electricity Electricity, onsite generation. Electricity, light Fairly centralized Less centralized Less centralized Highly centralized 23 mW/cm2 Gaussian distribution Unknown Unknown (10 mW/cm2 at edge) 1.15 kW/m2 (1 Sun) Atmosphere Transmission Ionosphere heating might affect telecommunications Tropospheric heating might modify weather over smaller area; problems with clouds? Effluents Possible effects include alteration of magnetosphere (AR+), increased water content; LEO orbit, smaller size, smaller launch vehicles formation of noctilucent clouds; ionosphere depletion Electromagnetic Interference RFI from direct coupling, spurious noise, and harmonics, Impacts on communications, If visible light IS used there may be problems Problem for optical astronomy, optical reflec- satellites etc from 245 GHz Problem for radio astronomers (GEO obscures portion of for optical astronomy if Infrared IS used may hens and Interference from beam change sky always) optical reflections from satellites and LEO stations WiII change the night sky Increase airglow optical reflection from LEO night sky in vicinity of sites satellite. Bioeffects Microwave bioeffects midbeam could cause thermal heating, unknown effects of long Direct beam ocular and skin damage ocular Psychological and physiological effects of 24- term exposure to low-level microwaves Ecosystem alteratlon? Birds avoid/attracted damage from reflections? Other effects? Birds hour illumination not known. Possible ocular to beam? flying through will burn up? If visible WiII hazard if viewed with binoculars? Ecosystem birds avoid? Ecosystem alterations? alteration National security weapons potential GEO gives a good vantage point over hemisphere Direct weapon: as ABM, antisatellite, aimed at Indirect: night illumination psychological– terrestrial targets possible weather modification –Provides a lot of power m space platform for surveillance, jamming– Indirect: power killer satellite, planes space platform –Requires development of large space fleet with/military potential– Laser defend self, best, LEO more accessible Vulnerability Satellites may need self defense system to protect against attack Less ground sites; a lot of mirrors-redun- Size and distance strong defenses– dancy; individual mirrors fragile; ground sites still produce power in absence of space system

International Will require radio frequency allocation and orbit assignment LEO more accessible to U S S R and high-latitude countries, smaller parcels of energy make Smaller parcels of energy make system more system more flexible flexible Meet environmental and health standards?

a smaller SOLARES systems, e g , IO GW/site would be possible and probably more desirable b$l02 billilon–NASA estimate+ncludes Investment Costs cEstimates byArgonneNational Laboratory, Office of Technology Assessment, u.s. Congress SOURCE Office of Technology Assessment. 10 . Solar Power Satellites

responsibilities between the public and private ticipants, would be an essential part of SPS de- sectors, and among potential international par- velopment. PUBLIC ISSUES

Public opinion about SPS is currently not Reference System —Rectenna/ well-formed. Discussion of SPS has been lim- Washington, D. C., Overlay ited to a small number of public interest groups and professional societies. In general, those in favor of SPS also support a vigorous U.S. space program, whereas many of those who oppose SPS fear that it would drain resources from small-scale, terrestrial solar technologies. Assum- ing acceptance of a decision to deploy SPS, public discussion is likely to be most intense at the siting stage of its development. Key issues that may enter into public thinking include environment and health risks, land-use, military implications, and costs. Centralization in the decisionmaking process and in the ownership and control of SPS may also be important. From the standpoint of public perceptions, the siting of land-based receivers could be an obstacle to the deployment of SPS unless: ● the public is actively involved in the siting process; ● health and environment uncertainties are diminished; and • local residents are justly compensated for SOURCE: Off Ice of Technology Assessment. the use of their land. Offshore siting of receivers could minimize potential public resistance to SPS siting. ENVIRONMENT AND HEALTH Many of the environmental impacts associated non ionizing radiation, electromagnetic inter- with SPS are comparable in nature and magnitude ference with other systems and astronomy, and to those resulting from other large-scale terres- radiation exposure for space workers. More re- trial energy technologies. A possible exception search in these areas would be required before

is coal, particularly if CO2 concerns are proven decisions about the deployment or devel- justified. While these effects have not been opment of SPS could be made. Little informa- quantified adequately, it is thought that con- tion is currently available on the environ- ventional corrective measures could be pre- mental impacts of SPS designs other than the scribed to minimize their impacts. However, reference system. Clearly, environmental several health and environmental effects, which assessments of the alternative systems will be are unique to SPS and whose severity and likeli- needed if choices are to be made between SPS hood are highly uncertain, have also been iden- designs. tified. These include effects on the upper atmosphere from launch effluents and power Too little is known about the biological effects transmission, health hazards associated with of long-term exposure to low-level microwave

Ch. 1—Summary . 11

Photo credit: National Aeronautics and Space Administration An artist’s concept of an offshore antenna that would receive microwave energy beamed from a large space solar power collector in geosynchronous orbit radiation to assess the health risks associated tional standards. Even more stringent micro- with SPS microwave systems. The information wave standards couId increase land require- that is available is incomplete and not directly ments and system cost or alter system design relevant to SPS. Further research is critically and feasibility. In Iight of the widespread pro- needed in order to set human-health exposure liferation of electromagnetic devices and the limits. Currently, no microwave population ex- current controversy surrounding the use of posure standard exists in the United States. microwave technologies, it is clear that in- The recommended limit for occupational ex- creased understanding of the effects of micro- posure is set at 10 mW/cm2 in the United waves on living things is vitally needed even if States, 1,000 times less stringent than the pres- SPS is never deployed. ent U.S.S.R. occupational standard. Public exclusion boundaries around the reference de- Exposure of space workers to ionizing radiation sign have been established at one one-hun- is a potentially serious problem for SPS systems dredth of U.S. occupational guidelines. It is an- that operate in geosynchronous orbit (CEO). Re- ticipated that future maximum permissible cent estimates indicate that the radiation dose U.S. occupational standards will be lower by a of SPS reference system personnel in CEO factor of 2-Io; population standards, if estab- would exceed current limits set for astronauts lished, may well be lower than the occupa- and could result in a measurable increase in 12 Ž Solar Power Satellites

Summary of SPS Environmental Impacts

System component Occupational health characteristics Environmental— impact Public health and safety and safety Power transmission b Microwave — bIonospheric heating could — Effects of Iow-level —Higher risk than for . disrupt telecommunications. chronic exposure to micro- public; protective Maximum tolerable power waves are unknown. clothing required for density is not known. — Psychological effects of terrestrial worker. Effects in the upper microwave beam as weapon. —Accidental exposure to ionosphere are not known —Adverse aesthetic effects high-intensity beam in —Tropospheric heating could on appearance of night sky. space potentially severe result in minor weather but no data. modification. — bEcosystem: microwave bioeffects (on plants, animals, and airborne biota) largely unknown; reflected light effects unknown. —b Potential interference with satellite communications, terrestrial communications, radar, radio, and optical astronomy.

Lasers —Tropospheric heating could —Ocular hazard? —Ocular and safety modify weather and spread — Psychological effects of hazard? the beam. laser as weapon are — Ecosystem: beam may possible. incinerate birds and —Adverse aesthetic effects vegetation. on appearance of night — bPotential interference sky are possible. with optical astronomy, some interference with radio astronomy.

Mirrors — bTropospheric heating —Ocular hazard? —Ocular hazard? could modify weather. —Psychological effect of —Ecosystem: effect of 24- 24-hr sunlight. hr light on growing — b Adverse aesthictic effects cycles of plants and cir- on appearance of night cadian rhythms of animals. sky are possible. — bpotential interference with optical astronomy.

Transportation and space operation Launch and recovery —Ground cloud might pollute —Noise (sonic boom) may —b Space worker’s hazards: air and water and cause exceed EPA guidelines. ionizing radiation possible weather modi- –Ground cloud might affect (potentially severe) HLLV fication; acid rain air quality; acid rain weightlessness, life PLV probably negligible. probably negligible. support failure, long COTV — b Water vapor and other —Accidents-catastrophic stay in space, POTV launch effluents could explosion near launch construction accidents deplete ionosphere and site, vehicle crash, toxic psychological stress, enhance airglow. Result- materials. acceleration. ant disruption of com- —Terrestrial worker’s munications and satellite hazards: noise, trans- surveillance potentially portation accidents. important, but uncertain. — b possible formation of noctilucent clouds in stratosphere and mesosphere; effects on climate are not known. Ch. 1—Summary ● 13

Summary of SPS Environmental Impacts—Continued

System component Occupational health characteristics Environmental impact Public health and safety and safety — bEmission of water vapor could alter natural hydrogen cycle; extent and implications are not well- known. — bEffect of COTV argon ions on magnetosphere and plasma-sphere could be great but unknown. —Depletion of ozone layer by effluents expected to be minor but uncertain. —Noise.

Terrestrial activities Mining — Land disturbance —Toxic material exposure. —Occupational air and (stripmining, etc.). —Measurable increase of water pollution. —Measurable increase of air and water pollution. —Toxic materials exposure. air and water pollution. — Land-use disturbance. —Noise. —Solid waste generation —Strain on production capacity of gallium arsenide, sapphire, silicon, graphite fiber, tungsten, and mercury. — Manufacturing —Measurable increase of — Measurable increase of —Toxic materials exposure. air and water pollution. air and water pollution. —Noise. —Solid wastes. —Solid wastes. —Exposure to toxic materials.

Construction —Measurable land — Measurable land —Noise. disturbance. disturbance. —Measurable local —Measurable local increase —Measurable local increase increase of air and water of air and water pollution. of air and water pollution. pollution. —Accidents.

b Receiving antenna — bLand use and siting— — Land use—reduced — Waste heat. —Waste heat and surface property value, aesthetics, roughness could modify vulnerability y (less land weather. for solid-state, laser options; more for reference and mirrors).

b High-voltage — bLand use and siting— — Exposure to high intensity —bExposure to high transmission lines — bEcosystem: bioeffects of EM fields—effects intensity EM fields— (not unique to SPS) powerlines uncertain. uncertain. effects uncertain. a impacts based on SPS systems as currently defined and do not account for offshore receivers or possible mitigating system modifications. bResearch priority. SOURCE: Office of Technology Assessment. 14 Ž Solar Power Satellites cancer incidence. However, there are a large a severe drawback for the microwave option. number of uncertainties associated with quan- Satellite communications and optical and tifying the health risks of exposure to ionizing radio astronomy would be seriously affected. radiation. More research would be required to The effects on radio and optical astronomy reduce these uncertainties and to identify and would be the most difficult to ameliorate. The evaluate system designs and shielding tech- minimum allowable spacing between geosyn- niques that would minimize risks at an accept- chronous power satellites and geosynchronous able cost. In addition, acceptable SPS radia- communications satellites is not well-known. tion limits would have to be determined. If The optical interference effects of either the CEO SPS systems are to be considered, an mirror or laser transmission options would be assessment of the health risks associated with of great concern to ground-based astronomers. space radiation is a top priority. Any of the SPS options would alter the appearance of the nighttime sky. Some may find The potential for interference with other users . this esthetialIy objectionable. of the electromagnetic spectrum could constitute

SPACE CONTEXT

The hardware, experienced personnel, and in- attention to SPS. An SPS research and develop- dustrial infrastructure generated by an SPS project ment program would be in accord with current would significantly increase U.S. space capabil- space policy that calIs for peaceful develop- ities and, in conjunction with other major ment of commercial and scientific space space programs, could lay the groundwork for capab i I i t i es the industrialization, mining, and perhaps the settlement of space. NASA is likely to play a Given the current absence of long-term pro- major role, especialIy in the initial stages of de- gram goals for the U.S. civilian space program, velopment. Non-SPS programs could be aided it is difficult to predict the effects of an SPS by accelerated development of transportation project on NASA plans or on private-sector ca- and other systems; on the other hand, they pabilities These effects will need to be care- could be harmed by the diversion of funds and fully considered. Chapter 2 INTRODUCTION Chapter 2 INTRODUCTION

As the United States and the world have be- ferent degrees of technical feasibility. In addi- gun to face the realities of living with a limited tion, they would affect the environment and supply of oil and gas, and the political uncer- political and financial institutions in different tainties that accompany impending scarcity, ways. the search for reliable, safe means of using the The first serious discussion of the SPS con- radiant energy of the Sun has intensified. Solar cept appeared in 1968. ’ 2 During the next few radiation is already used in many parts of the years several companies conducted prelimi- Nation for direct space heating and for heating nary analyses with some support from the Ad- water. It can also produce electricity by photo- vanced Programs Off ice of the National Aero- voltaic and thermoelectric conversion. How- nautics and Space Administration (NASA).3 ever, nearly all terrestrial solar collectors and In May 1973, the Subcommittee on Space converters suffer from the drawbacks of the Science and Applications of the House Science day-night cycle. On Earth, sunlight is only and Astronautics Committee heId the first con- available during daylight hours, but energy is gressional hearings on the concept.4 Following consumed around the clock. In the absence of those hearings, NASA began a series of experi- inexpensive storage, nighttime and cloud cov- ments in microwave transmission of power at er limit the potential of terrestrial solar tech- the Jet Propulsion Laboratory. In 1975, NASA nologies (with the exception of ocean thermal created an SPS study office at the Johnson energy conversion) to supply the amounts of Space Center that performed several addi- energy required for use in homes, businesses, tional systems studies. A number of papers and industries. By placing the solar collectors s were published, culminating in an extensive in space where sunlight is intense and con- report that established most of the basis for stant, and then “beaming” energy to Earth, the the Department of Energy’s (DOE) reference solar power satellite (SPS) seeks to assure a 6 system design. baseload supply of electricity for terrestrial consumers. In the beginning it had been assumed that NASA would be the Federal agency with prime Several radically different versions of SPS responsibility for satellite power stations. have been proposed, most of which will be de- However, the Solar Energy Act of 1974 clearly scribed and analyzed in this report. In the most placed the responsibility for all solar energy extensively studied version, a large satellite R&D aimed at terrestrial use under the jurisdic- would be placed in the geosynchronous orbit 1 so that it remains directly above a fixed point P E Claser, “The Future of Power From the Sun, ” lntersocie- on the Earth’s Equator. Solar photovoltaic ty Energy Conversion Engineering Conference (l ECEC), IEEE publication 68C-21 -Energy, 1968, pp. 98-103, panels aboard the satellite would collect the 2 P E Glaser, “Power From the Sun: Its Future,” Science 162, Sun’s radiant energy and convert it to elec- NOV 22, 1968, pp. 857-886, tricity. Devices would then convert the elec- ‘P E Claser, O. E, Maynard, J. Mockovciak, and E, L, Ralph, “Feasibility Study of a Satellite Solar Power Station,” Arthur D. tricity to microwave radiation and transmit it Little Inc , NASA CR-2357 (contract No. NAS 3-16804), February to Earth where it would be collected, recon- 1974. verted to electricity, and delivered to the elec- “’Power From the Sun via Satellite, ” hearings before the Subcommittee on Space Science and Applications and Subcom- tric power grid. An alternative concept envi- mittee on Energy of the Committee on Science and Astronautics, sions using large orbiting reflectors to reflect U S House of Representatives, May 7, 22, 24,1973. solar radiation to the ground, creating im- 5Wlll lam J. Richard, “Geosynchronous Satellite Solar Power,” ch, 8 of So/ar Energy for Earth: An A /AA Assessment, H. J. Kill ian, mense solar farms where sunlight would be G L Dugger, and J. Grey (eds.), AlAA, Apr. 21, 1975, pp. 59-71. available around the clock. Laser beams have (Also see abridged version in Astronautics and Aeronautics, also been proposed for the energy transmission November 1975, pp. 46-52.) “’ln(tlal Technical, Environmental, and Economic Evaluation medium. These concepts may have significant- of space solar Power Concepts, ” report No. j SC-11568, VOIS. I ly different economic prospects, as well as dif- and II, NASA, Aug. 31, 1976.

17 18 ● Solar Power Satellites

tion of the Energy Research and Development another round of hearings, ’2 and eventually Administration (ERDA). ERDA set up a Task passed by the full House. No Senate bill was in- Group on Satellite Power Stations, and in No- troduced. A similar bill,13 reintroduced in 1979, vember 1976 recommended two options for was passed by the House on November 16, conducting a joint ERDA/NASA 3-year SPS 1979, but again died in the Senate. concept development and evaluation pro- The DOE/NASA Concept Development and gram, one costing $12 million and one $19 mil- Evaluation Programwas14 established to iden- lion. ’ ERDA elected to pursue a median tify and evaluate the possible technical, en- course, and proposed a 3-year, $15.5 million ef- vironmental, social, institutional, and econom- fort which began in fiscal year 1977, the SPS ic aspects of the SPS concept. It has generated Concept Development and Evaluation Pro- a broad range of reports that reflect this in- gram. tent. 5 In order to have a fixed technical basis ERDA’s efforts were given impetus by two for the study, DOE and NASA developed two congressional hearings, one held in January versions of a “reference” satellite power sta- 1976 by the Subcommittee on Aerospace Tech- tion system, based on extensive studies under- nology and National Needs of the Senate taken by two NASA contractors. 16 17 Although Aeronautical and Space Sciences Committee8 the reference system represented the best and one held in February 1976 by two subcom- choice based on the information available at mittees of the House Committee on Science the time, it was not intended to be the last and Technology.9 word in systems definition; the multitude of other options that have been proposed since When DOE was created in 1977, it estab- also need to be evaluated before ultimately lished a special Satellite Power System project settling on a “baseline” system design. office in the Office of Energy Research to complete the Concept Development and Evalua- OTA was requested by the House Commit- tion Program. Its final report was released on tee on Science and Technology to pursue an December 1, 1980.’0 independent study to “assess the potential of The SPS research, development, and demon- the SPS system as an alternative source of energy.’” 8 Hence, this study primarily ad- stration bill, ’ which was introduced in the dresses the benefits and drawbacks of SPS as House of Representatives on January 30, 1978, an energy system. It also identifies the key reflected a desire by a number of Members of Congress to accelerate the evaluation of SPS and to introduce a more ambitious technology “’Solar Power Satellite, ” hearings before the Subcommittee verification effort. It was reported out by the on Space Science and Applications and the Subcommittee on Science and Technology Committee after Advanced Energy Technologies and Energy Conservation Re- search, Development, and Demonstration of the Committee on Sc[ence and Technology, U.S. House of Representatives, Apr 7Robert A. Summers (chairman), “Final Report of the ERDA 12-14, 1978 (No, 68), CPO stock No. 28-155-0, 1978, Task Croup on Satellite Power Station,” report No. ERDA-76/l 48, ‘ ‘Ronnie Flippo, “Solar Power Satellite Research, Develop- November 1976. ment, and Evaluation Program Act of 1979, ” H R. 2335, Feb. 22, “’Solar Power for Satellites, ” hearings before the Subcommit- 1979 tee on Aerospace Technology and National Needs of the Com- “’’Satellite Power System Concept Development and Evalua- mittee on Aeronautical and Space Sciences, U S. Senate, J an, 19, tion Program Reference System Report,” U S. Department of 21,1976, GPO stock No, 66-608-0, 1976 Energy report No DOE/E R-0023r October 1978. “’Solar Satellite Power System Concepts,” hearings before the ‘sSee the extensive set of references in note 10 Subcommittee on Space Science and Applications and the Sub- “C Woodcock, “Solar Power Satellite System Definition committee on Energy Research, Development, and Demonstra- Study, ” Boeing Aerospace Co., Johnson Space Center (contract tion of the Committee on Science and Technology, U.S. House of No NAS 9-151 96), pt. 1, report No. DI 80-22876, December 1977, Representatives, Feb. 20,1976 (No 67) pt 111, report No D18024071, March 1978 ‘“Satellite Power Systems Concept Development and Evalua- “C Hanley, “Satellite Power System (SPS) Concept Defini- tion Program, “Program Assessment Report Statement of Find- tion, ” Rockwell International Corp., Marshall Space Flight Cen- ings, ” DOE/E R-0085, November 1980, ter, (contract No. NAS 8-32475), report No. SD78-AP-0023, April “Ronnie Flippo, “Solar Power Satellite Research, Develop- 1978 ment, and Demonstration Program Act of 1978, ” H .R 10601, J an. “Letter of request to OTA from the House Committee on 30,1978. SC Ience and Technology, Aug 8,1978 Ch. 2—Introduction ● 79

uncertainties of the various SPS concepts and range of viewpoints from participants related needs for R&D. who have a sense of the issues, the political players, and public attitudes involved. Although SPS would be an energy system it The energy context of SPS. SPS will suc- is unique in being a major space system as ceed or fail in competition with other en- well. It would therefore require a large new ergy supply options and in the context of commitment to the development of space national and global demand for electric- technology. Hence, this report also addresses ity. This workshop developed criteria for the relationship of an SPS program to other choosing between technologies and com- space programs. pared the major future alternative renew- OTA has divided the assessment into four able or inexhaustible sources of baseload major areas: 1) SPS technical alternatives and electrical power. Participants discussed economics, 2) issues arising in the public de- the many factors that wouId affect future bate, 3) institutional and international ques- electricity demand and compared breeder tions, and 4) the programmatic context, i.e., reactors, fusion, terrestrial solar thermal, the place of SPS within our national energy and solar photovoltaic baseload options. and space programs. A number of working They also discussed the potential role of papers were written to provide data for these dispersed photovoltaic systems in meeting areas. OTA also convened three workshops to part of the Nation’s electrical needs. refine and amplify the data presented in sev- Because the SPS concept would use a com- eral of the working papers: 1) SPS Technical plex future technology about which there are Options and Costs, 2) SPS Public Opinion many uncertainties, this assessment is funda- Issues, and 3) The Energy Context of SPS. mentalIy different from an assessment of cur- ● • SPS technical options and costs. The ma- rent technology. While it is thought to be tech- jor task of the workshop was to assess the nically feasible, many of the details are un- DOE/NASA reference system from a tech- certain; economic projections or possible en- nical perspective and to study alterna- vironmental effects based on them are also un- tives. It discussed the key uncertainties of certain, sometimes by more than an order of each major system or subsystem that has magnitude. Hence at this point OTA must be been suggested in SPS literature and satisfied with identifying the key uncertainties chose four generic systems for further of SPS and, where applicable, suggesting alter- evaluation in later workshops: 1) the ref- nate strategies for resolving them. The study erence system, 2) a solid-state variant of also analyzes the major institutional and inter- the reference system, 3) a laser system, national issues that accompany decisions and 4) a mirror system. about SPS, i.e., how it may affect national ● SPS public opinion issues. Participants security, the international energy market, the with experience in analyzing and respond- utilities industry, and how an SPS project ing to a variety of public interests and might be financed and managed. Although a concerns met to identify the major issues definitive treatment of any of these issues that could affect the public perceptions must wait for the future, this report attempts of SPS. The workshop was not an exercise to lay the foundation for further consideration in public participation. Rather, it sought a of SPS. Chapter 3 ISSUES AND FINDINGS Contents

Page Page Technical Options ...... , . . . 23 Terrestrial Communications and Microwave Transmission ...... 23 Electronic Systems ...... 50 Laser Transmission ...... 24 Effect on Terrestrial Astronomy Reflected Sunlight ...... 27 and Aeronomy ...... 50 SPS Scale ...... 28 Space Program ...... 52 Costs ...... 29 SPS and the Energy Future ...... 30 SPS ls Not Likely To Be Commercially LIST OF TABLES Available Before 2005-15 ...... 30 SPS Would Not Reduce U.S. TableNo. Page Dependence on lmported Oil ...... 32 l, Characterization of Four Alternative SPS Potential Scale of Electrical Power. ,... 32 Systems ...... 31 Electricity Demand Would Affect the 2. Major lssues Arising in SPS Debate ...... 42 Need for Solar Power Satellites...... 32 3. Summary of SPS Environrnental Impacts. . . . 43 Comparison to Other Renewable 4. SPS Systerns Land Use ...... 47 Options ...... 33 Utilities...... 33 Nontechnical Considerations ...... 35 LIST OF F GURES Ownership and Finance ...... 36 Figure No. Page International implications ...... 37 1 The Reference System ...... 24 2 The Solid-State Variant of the Reference National Security Implications...... 38 System ...... 25 Public Issues...... 41 3 The Laser Concept ...... 26 4 The Mirror Concept (SOLARES) ...... 28 Environment and Health...... 41 5. Reference System Costs ...... 29 Electromagnetic Compatibility ...... 48 6. The Number of Geosynchronous The Public ...... 48 Satellites as a Function of Time ...... 49 Space Communications ...... 48 7. The SPS Brightness Profile ...... 51 TECHNICAL OPTIONS

What technical options might be available high voltage. It would then be either rectified for SPS?* to dc and delivered directly to a dc transmission network in the terrestrial utility grid or A number of technical options for the solar used as conventional ac power. The rectenna power satellite (SPS) have been proposed. Be- 2 covers a ground area of 102 km and would re- cause SPS is a developing technology, the spe- quire an “exclusion area” around it of an addi- cific design parameters of each of these ap- 2 tional 72 km to protect against exposure to proaches are evolving rapidly as research con- low-level microwaves. The beam density at the tinues. Hence no single option is completely center of the rectenna is 23 milliwatts per defined, nor are there detailed systems studies 2 square centimeter (mW/cm ). The beam is of any designs other than the National Aero- shaped in such a way that at the edge of the ex- nautics and Space Administration/Department 2 clusion area it reaches 0.1 mW/cm . of Energy (NASA/DOE) “reference system” that uses microwaves for transmitting energy For the given set of design assumptions for from space to Earth. The reference design is the reference system, i.e., beam density, taper, the basis for the NASA/DOE environmental, so- and frequency, the maximum power per trans- cietal, and comparative assessments. The two mitter-receiver combination would be 5,000 other major SPS variants depend on laser trans- MW. Except for a small seasonal variation in mission of power from space and on reflected output due to the variation of the Sun’s dis- sunlight. tance from the Earth, and short periods of shadowing by the Earth near the time of the Microwave Transmission spring and fall equinoxes, each reference system satellite could be expected to deliver the The Reference System Design maximum amount of power to the grid approximately 90 percent of the time. This power The reference system satellite conceptual design consists of a 55 square kilometer level was selected by NASA/DOE for the ref- (km2)** flat array of photovoltaic solar cells erence system in the belief that it would pro- located in the geostationary orbit 35,800 km vide energy at the lowest cost. 1 n subsequent above the Earth’s Equator (fig. 1). The cells discussions it is used to consider the impact of convert solar energy into direct-current (de) the reference system design on utilities and electricity that is conducted to a 1-km diame- their systems; however, the power level could be set at any value permitted by the design ter microwave transmitting antenna mounted at one end of the photovoltaic array. Micro- constraints. wave transmitting tubes (klystrons) convert the The reference system, which was developed electrical current to radio-frequency power at to provide a base for further studies and is now 2.45 gigaHertz (GHZ), and transmit it to Earth. several years old, is far from an optimum A ground antenna receives the electromag- microwave system and could be substantially netic radiation and rectifies it back to direct improved. In addition, alternative concepts current; hence its designation “rectenna.” The that depend on laser transmission or passive direct-current (de) power can be inverted to reflection of sunlight each offer certain alternating-current (ac) and “stepped up” to specific benefits over the microwave designs. Because none of these alternatives are as well

*See ch. 5. defined as the reference system, they are **Equivalent to about 13,600 acres discussed here in more general terms.

23 24 . Solar Power Satellites

Figure 1 .—The Reference System

Array structure

Solar cell array

Transmitting antenna subarray

DC-RF power amps

Antenna waveguides

SOURCE: C. C. Kraft, “The Solar Power Satellite Concept,” NASA publication No. JSCp14898, July 1979.

The Solid-State Variant Laser Transmission

Using solid-state devices that convert elec- Lasers constitute an obvious alternative to tricity from the satellite’s solar array directly microwaves for the transmission of power over to microwave power would be a possible alter- long distances. Compared with microwaves, native to the reference system’s klystrons. lasers have a much smaller beam diameter; Such devices might have a longer working life- since the aperture area of both transmitting time and require less mass in orbit; when cou- and receiving antennas decreases as the square pled with photovoltaic cells in a “sandwich” of the wavelength, light from an infrared design, they would also allow for a much larger wavelength laser can be transmitted and re- transmitting antenna (the entire surface area ceived by apertures over 100 times smaller in of the solar cells would, in effect, be the anten- diameter than a microwave beam. This re- na), smaller earthside antennas, and lower duces the size and mass of the space segment power delivered to Earth per satellite (i.e., and the area of the ground segment. Perhaps about 1,000 MW per rectenna). In combina- even more important, the great reduction in tion, these effects would make it possible to aperture area permits consideration of fun- position rectennas closer to the cities, which damentally different systems. For example: would be the major users of SPS generated ● It would become possible to use low Sun- power, than would the reference system synchronous rather than high geostation- design. ary orbits for the massive space power Solid-state devices are now in the very early conversion subsystem (a Sun-synchronous stages of being evaluated for SPS application. orbit is a near-polar low Earth orbit that It is still unclear whether they would be able to keeps the satellite in full sunlight all the reach the efficiency and cost goals that would time while the Earth rotates beneath it). be necessary for SPS. The primary laser would then beam its Ch.3— Issues and Findings ● 25

Figure 2.—The Solid-State Variation of the Reference System

Reflected sunlight cell

Solid-state amplifier panel

Solar array/microwave antenna sandwich panels

SOURCE: G. M. Hanley, et al., “Satellite Power Systems (SPS) Concept Definition Study First Performance report No. SS D 79-0163, NASA MSFC contract No. NAS8-32475, Oct. 10, 1979.

power up to low-mass laser mirror relays ● The potentially small size of the receiving in geostationary orbit for reflection down station would make it possible to employ to the Earth receiver. This arrangement, multiple locations close to the points of while complex, would considerably reuse, thereby simplifying the entire ground duce the cost of transportation, since the distribution and transmission system. bulk of the system would be in low Earth ● Laser power transmission would avoid the orbit rather than in geostationary orbit. It problem of microwave biological effects also could be built with smalIer trans- and would reduce overall interference portation vehicles than the reference sys- with other users of the electromagnetic tem’s planned heavy lift launch vehicle spectrum. (HLLV). A laser SPS would suffer from three impor- ● A laser system might be able to operate tant disadvantages: efficiently and economically on a smaller scale (100 to 1,000 MW). Thus, it would ● Absorption of laser radiation. Infrared ra- offer the flexibility of power demand diation is subject to severe degradation or matching on the ground, making possible absorption by clouds. A baseload system, higher degrees of redundancy and a unlike the microwave option, would re- smaller and therefore less costly system quire considerable storage capacity to demonstration project. make up for interruptions. Multiple re-

83-316 0 - 81 - 3

26 ● Solar Power Satellites

Figure 3.—The Laser Concept (One Possible Version)

1Solar power satellite Relay unit(s)

Ground site

Synchronous relays

Occulted power Sun satellites Ch. 3—Issues and Findings ● 27

ceivers at different locations to achieve reach the efficiencies and reliability necessary some redundancy are also possible, but for an SPS. expensive (seeUtilities, ch. 9). ● Efficiency. Current high-power, continu- Reflected Sunlight ous-wave lasers are only capable of very Instead of placing the solar energy conver- low overall power conversion efficiencies sion system in orbit, large orbiting mirrors (less than 25 percent). Converting the could be used to reflect sunlight to ground- beam back into electricity is also ineffi- based solar conversion systems. Thus, the sys- cient, though progress in this area has tern’s space segment could be much simpler been rapid. The relatively undeveloped and therefore cheaper and more reliable. status of laser generation and conversion means that considerable basic and ap- One such system would consist of a number plied research would be needed to deter- of roughly circular plane mirrors in various mine the feasibility of a laser SPS. nonintersecting Earth orbits, each of which directs sunlight to the collectors of a number ● Health and safety hazard. The beam inten- of ground-based solar-electric powerplants as sity would be great enough to constitute a it passes over them. Conversion from sunlight health and safety hazard. Preventive measures could include a tall perimeter to electricity would occur on the surface of the wall, and/or a warning and defocusing Earth. system. In one approach, (the so-called “SOLARES baseline” concept) about 916 mirrors, each 50 Several types of continuous wave lasers cur- km2 in area, would be required for a global rently exist. Of these, the most highly devel- power system projected to produce a total of oped and most appropriate laser for SPS would 810 gigawatts (GW) (more than three times cur- be the electric discharge laser (EDL). At pres- rent U S. production) from six individual sites. ent, EDL models have achieved only modest This is not necessarily the optimum SOLARES power levels and relatively low efficiencies system. It was selected here to demonstrate when operated in a continuous mode. the magnitude of power that might be achieved with such a system. However, a num- Another future option that has been consid- ber of different mirror sizes, orbits, and ground ered is the solar-pumped laser. In this device, station sizes are possible. A more feasible op- concentrated sunlight is used directly as the tion would be a lower orbit system (2,100 km) exciting agent for the laser gases. Although a to supply 10 to 13 GW per terrestrial site. One solar-pumped laser has been built and oper- of the principal features of the SOLARES con- ated successfully at NASA Langley, it would re- cept is that it could be used for either solar- quire considerable basic research, develop- thermal or solar photovoltaic terrestrial plants. ment, and testing before it could be a realistic The fact that energy conversion would take prospect for SPS. place on the surface of the Earth keeps the mass in orbit small, thereby reducing trans- Free electron lasers (FELs) offer another portation costs. possible means of transmitting power from space. These new devices are powered by a However, a major disadvantage of such a beam of high-energy electrons which oscillate mirror system would be that the entire system in a magnetic field in such a way that they would require an extremely large contiguous radiate energy in a single direction. Although land area for the terrestrial segment (see table the FEL has been demonstrated experimental- 4, p. 47). As with the laser designs, transmission Iy, it is too early to predict whether it would through the atmosphere would be subject to

28 • Solar Power Satellites

Figure 4.–The Mirror Concept (SOLARES)

Photo credit National Aeronautics and Space Administration

SOURCE: K. W. Billman, “Space Orbiting Light Augmentation Reflector Energy System: A Look at Alternative Systems,” SPS Program Review, June 1979. reduction or elimination by cloud cover. It trical power to the United States or to other would also illuminate much of the night sky countries. However, its very scale is seen by (see issue on electromagnetic interference) as many as a serious drawback to deployment. seen by observers within a 150-km radius of the The utilities here and abroad would find it groundsite center. hard to accommodate power in 5,000 MW blocks (see Utilities, ch. 9), and the space transportation system needed to build and SPS Scale maintain such a massive system would be very expensive. Thus, it is of considerable interest As presently conceived, the reference sys- to investigate ways in which the scale of the tem is a large-scale project that has the poten- various components, and of the system itself, tial of delivering hundreds of gigawatts of elec- couId be reduced to a more manageable size.

Ch. 3—Issues and Findings ● 29

The laser system would offer the potential The most detailed cost estimates have been for the most substantial reductions, both in made by NASA for the reference system (fig. 5): overall system size and in the size of the first $102.4 billion to achieve the first complete demonstration project. This reduction in scale reference system satellite, and $11.3 billion to might also bring with it a concomitant reduc- construct each satellite thereafter. tion of costs. There are also a number of possi- These estimates included the costs of the en- ble ways in which to reduce the physical scale tire transportation system, the costs of estab- of portions of the microwave system. How- lishing the launch sites and construction facil- ever, economies of scale tend to drive micro- ities in low-Earth and geosynchronous orbits, wave systems to sizes of 1,000 MW output or as well as all of the component development more.

SPS would require a massive industrial infra- Figure 5.—Reference System Costsa structure for space transportation and con- (dollars in billions) struction and for related terrestrial construction, comparable in scale to that developed for existing ground-based coal and nuclear systems. ● Space transportation. The reference system assumes the construction and use of a large third-generation, shuttle-type transportation system. Construction of a single reference system satellite (silicon photovoltaics) would require approximately 190 flights of an HLLV. However, launch vehicles somewhat larger than the current shuttle, but smaller than the HLLV, are capable of operating with less load per flight but with many more flights and might be more economical. I n addition, an intermediate size vehicle would be more appropriate for other uses in space. No other currently planned space project envisions using vehicles the size of an HLLV. ● Space construction. SPS would require construction bases in low Earth orbit and, for some designs, at geostationary orbit. It might be possible to achieve substantial cost reductions by constructing the satellites in low Earth orbit and transporting them to geostationary orbit, rather than by constructing them in geostationary orbit.

costs Although the costs of many SPS components

have been estimated by a number of different aNASA estimates— 1977 dollars. agencies, it is not yet possible to establish them with any reasonable level of confidence. SOURCE: National Aeronautics and Space Administration 30 ● Solar Power Satellites

costs. However, they do not include interest on transmitter of the reference system; however, the invested capital or the potential use of SPS some of the development cost could con- facilities for other space or terrestrial projects. ceivably be borne by other laser applications, According to one possible development sce- e.g., directed energy weapons or inertial fu- nario generated by NASA (see fig. 24, p. 93), in- sion. The cost of a laser demonstration satel- cluding interest of 10 percent per year more lite might well be less than the reference sys- than doubles the development cost of SPS. tem demonstrator. Because of the relatively low mass and ease of construction and opera- By using a smaller capacity transportation tion of a SOLARES system, it may prove to be system (assuming more flights per satellite), much more attractive than other alternatives. and apportioning the development costs of Cost estimates suggest that if the cost of ter- generic space technology among all the space restrial photovoltaics can reach the goals im- programs that benefit from it, it might well be plied by reference system estimates, the costs possible to deploy a single reference satellite of a total SOLARES system would be less than for $40 billion to $50 billion, or roughly one- the reference system. More exact costs for the half of the above estimate. SPS await further information on the details of Other systems might cost more or less than the preferred system. Whatever system might the reference system, depending on the state be chosen, it is clear that the startup costs of development of the alternative technol- would be in the tens of billions. How much of ogies (see table 1). For example, since lasers this cost would have to be borne by the U.S. would need considerable development before taxpayer depends on the breadth and depth of they would be suitable for use in a laser- industrial and international interest in the de- powered SPS, they would be likely to be more velopment of SPS (see ch. 7). expensive to develop than the microwave

SPS AND THE ENERGY FUTURE

How could SPS flt into the U.S. energy future SPS Is Not Likely To Be Commercially (2000-30)?* Available Before 2005-15 SPS will ultimately be accepted or rejected Experience with other new electric generat- in the full context of future electrical demand ing technologies indicates that new technol- and supply technologies. It would compete ogies take from 30 to 45 years to become a with other renewable or inexhaustible energy significant source of electrical capacity in the sources such as hydro, wind, terrestrial solar, utility grid. SPS is unlikely to constitute a ma- ocean thermal energy conversion, fusion, fis- jor exception to this rule of thumb. If a decision breeder, and geothermal. Their tech- sion to develop SPS were made, some 15 to 25 nologies are all quite different; some serve a years of development, engineering, and dem- demand for baseload, some for peaking or onstration would be needed to reach a com- intermediate needs. Together, they would con- mercial SPS. However, because of the many stitute a mix of technologies designed to sup- uncertainties surrounding SPS, it is not yet ply the full range of electrical needs for the possible to make a development decision. If, United States. SPS must be considered in light after considerable further research a decision of its potential contribution to this mix, as well is made in the next decade to proceed with as of future electrical demand. SPS, then it could be commercially available in the period between 2005 and 2015. Several *See ch. 6, Energy section. years of operational testing beyond that would Table 1.—Characterization of Four Alternative SPS Systems

Information matrix Reference design Solid state Laser system SOLARES (“baseline”)a costs R&D $400 million More R&D needed than reference system More R&D needed than reference system Relatively simple technical lower cost Demonstration $102 billion DDT&E (one sateilite) b Smaller, demonstration with shuttle? $44 billion, demonstration with shuttle? Construction $11,5 billion/satellite Unit cost lower, smaller rectenna $3 billion satellite (0,5 GW) $1,300 billion for 810 GW total system Operation $200 million/yr-5GW Greater reliability, long lifetime 25 million/yr-satellite (0.5GW) Higher ground conversion cost Dollars/kW $2,900 -19,000/kWc $1 ,800 -3,000/kW (probably low) $6,000/kW probably low) $1,500/kW (probably low) Scale Satellite size 55 km2 18 km2 5 km2 50 km2 Number of satellites 60 (300 GW total) Not projected Not projected 916 (810 GW total) Power/satellite 5,000 MW 1,500 MW 500 MW 135,000 MW Mass 5 X104 tonnes/satellite, O 1 kW/kg Less mass than reference/O 1 kW/kg Less mass than reference/O .05 kW/kg 2 x 105tonnes mirror system 2 kW/kg Land use rectenna site 174 km2 (including buffer) 50 km2 0.6 km2 1,000 km2 x 60=10,440 km2 km2 1,000 MW 35 33 1,2 7.4 Energy Electricity Electricity Electricity, onsite generation. Electricity, light Fairly centralized Less centralized Less centralized Highly centralized 23 mW/cm2 Gaussian distribution Unknown Unknown (10 mW/cm2 at edge) 1.15 kW/m2 (1 Sun) Atmosphere Transmission Ionosphere heating might affect telecommunications Tropospheric heating might modify weather over smaller area; problems with clouds? Effluents Possible effects include alteration of magnetosphere (AR+); increased water content; LEO orbit, smaller size; smaller launch vehicles formation of noctilucent clouds; ionosphere depletion Electromagnetic interference RFI from direct coupling, spurious noise, and harmonics: impacts on communications, If visible light IS used there may be problems Problem for optical astronomy, optical reflec- satellites etc from 245 GHz Problem for radio astronomers (GEO obscures portion of for optical astronomy; if Infrared IS used may tions and interference from beam; change sky always) optical reflections from satellites and LEO stations WiII change the night sky Increase airglow optical reflection from LEO night sky in vicin of sites satellite Bioeffects Microwave bioeffects midbeam could cause thermal heating unknown effects of long- Direct beam ocular and skin damage ocular Psychological and physiological effects of 24- term exposure to low-level microwaves, Ecosystem alteration? Birds avoid/attracted damage from reflections? Other effects? Birds hour illumination not known Possible ocular to beam? flying through WiII burn up? If visible will hazard if viewed with binoculars? Ecosystem birds avoid? Ecosystem alterations? alteration National security weapons potential GEO gives a good vantage point over hemisphere Direct weapon: as ABM, antisatellite, aimed at Indirect: night illumination psychological– terrestrial targets possible weather modification –Provides a lot of power in space platform for surveillance, jamming– Indirect: power killer satellite, planes space platform –Requires developement of Iarge space fleet with/militarv potential– Laser defend self, best, LEO more accessible

Vulnerability Satellites may need self defense system to protect against attack Less ground sites; a lot of mirrors-redun- Size and distance strong defenses– dancy; individual mirrors fragile; ground sites still produce power in absence of space system International Will require radio frequency allocation and orbit assignment LEO more accessible to U.S.S.R. and high-lahtude countries, smaller parcels of energy make Smaller parcels of energy make system more system more fiexible flexible Meet environmental and health standards? asmaller saLAREs systems, e g 10 GW/sde would be possible and probably more desirable b$loz bllllon–NASA estimate–mcludes Investment costs cEst(mates by Argonne National Laboratory, Office of Technology Assessment, U S Con9ress SOURCE Offlceof Technology Assessment 32 ● Solar Power Satellites be needed before utilities developed enough Potential Scale of Electrical Power confidence in SPS to invest in it for their use (see ch. 9). The reference system is designed to deliver 5 GW (5,000 MW) of power to each rectenna. If a SPS Would Not Reduce U.S. 60-satellite U.S. fleet were completed, the SPS couId deliver a total of 300 GW, an amount Dependence on Imported Oil nearly one-half the current total U.S. generat- Currently the biggest energy problem facing capacity. Converted to energy at a capac- ing the Nation is dependence on unreliable ity factor of 90 percent, a 60-satellite system sources for imported oil. This dependence will would produce about 8 Qe/yr, more electrical persist for the next two decades, since our energy than we currently consume from all domestic supplies will continue to decline. We supply sources (7.5 Qe). An international fleet now produce about 10 million barrels per day of satelIites could achieve a much greater ca- (bbl/d) of petroleum liquids and this will likely pacity than this by placing more satellites in fall to 4 million to 7 million bbl/d by 2000. The geostationary orbit. A SOLARES-type system supply of abundant domestic energy resources could achieve an even greater generating such as coal, solar, uranium, and natural gas capacity on an international scale. can increase but not enough to offset the decline in oil. Over this period our best opportu- other proposals, such as the laser system nity for reducing dependence on imports will and variants of the microwave system might be be conservation, which has the potential of economical in somewhat smaller unit sizes cutting current dependence by more than 50 (500 to 1,000 MW). Precisely how much total percent. However, the real problem will be the energy they might supply is less clear, how- substantial reduction in availability of world ever. For example, a laser system supplying oil for export to the United States. The total power in 1,000 MW units would need 300 such amount of oil available is not likely to exceed satellites and ground receivers in order to the current level of 52 million bbl/d and may equal the capacity of a 60-satellite reference be as much as 15 percent below this level. Fur- system. ther, overall world demand will likely be higher because of increased needs by less developed countries (LDCS), including oil producing coun- Electricity Demand Would Affect the tries. As a result, the United States will find it Need for Solar Power Satellites necessary to reduce imported oil dependence considerably by 2000. This reduction will be The level of electricity demand in the United even more marked past 2000, when we can ex- States and the world will greatly affect the pect synthetic fuels from all sources to make a time that new centralized electric generating substantial contribution. Since the SPS will not technologies, such as SPS, might be needed. be able to make a significant contribution un- The demand for electricity could vary con- til well past 2000, it cannot be expected to sub- siderably over the next several decades. For stitute for foreign oil. However, the satellite the United States, current forecasts show a could eventually begin to substitute for coal- range in possible electrical demand from less fired powerplants since coal, too, is a finite than today’s level of 7.5 Qe end-use to more fuel, and regardless of the outcome of the CO, than 30 Qe by 2030. The demand level will be a controversy, use of it for electric production major determinant of the rate at which new will eventually (though probably not for the electric generating technologies need to be next 100 years) be reduced and reserved for introduced. At the lowest levels, all of our nonenergy needs, i.e., for plastics, synthetic baseload capacity could easily be supplied by fiber, etc. hydro and coal or nuclear for well into the 21st Ch. 3—Issues and Findings ● 33

century provided C02 buildup does not pre- Comparison to Other clude increased coal use. At high demand Renewable Options levels, however, it is unlikely that any one Ultimately the United States and the world technology could provide all the needed base- will choose or reject SPS as an energy supply Ioad capacity and several possibilities would option on the basis of comparative costs as be needed. In this case, development of SPS well as environmental and social impacts. OTA may be attractive, even assuming successful has generated a number of criteria for the development of fusion or breeder reactors. choice of energy technologies and compared SPS with other renewable or inexhaustible op- An emerging factor that will strongly affect tions (fusion, nuclear breeder, terrestrial solar electricity demand is the success in developing thermal, and solar photovoltaic) on the basis demand technologies that use electricity very of those criteria (see table 16, p. 11 6). What efficiently. It is likely over the next several emerges from such comparisons is that if the decades that the price of electricity will come research, development, demonstration, and close enough to other forms of energy (syn- testing (RDD&T) costs and the estimated cost thetic fuels, direct solar, etc.) that the relative per installed kilowatt can be lowered sig- efficiencies of the end-use equipment will de- nificantly, SPS could compete with the alter- termine which energy form is the cheapest. natives on an economic basis. SOLARES, for Therefore, electricity demand could grow con- instance, might already be economical com- siderably if such things as very efficient space pared to conventional nuclear. SPS technical and water heat pumps, electrochemical indus- uncertainties are much higher than for the trial processes, and high-capacity storage bat- breeder, but lower than for fusion. Social costs teries are developed. If these are not forth- are extremely difficult to determine, but if coming and the conventional ways of using en- research demonstrated the microwave and ergy–direct combustion of liquid and gaseous Ionizing radiation hazards to be low, SPS couId fuels–continue to be most prevalent, then substitute low-risk environmental hazards for electricity demand in the United States wilI not the high risks of coal or nuclear as well as con- increase rapidly if at al 1. Therefore, the even- tribute to an expanded space program. It tual need for solar power satellites and other wouId take longer to commercialize than ter- central electric technologies would be deter- restrial solar or breeder, but less than fusion. I n mined as much by the development of effi- competition with other technologies, overall cient electric demand technologies as by its demand for electricity, and the timing of the economics relative to other electric energy commercial introduction of SPS vis-a-vis other technologies. options wilI be crucial.

UTILITIES

Would SPS be acceptable to the utilities?* and available as their designers suggest they could be (90 percent or more), the utilities The major factors that would affect the util- would welcome them for baseload generation, ities’ decision about SPS technology are cost, assuming their size and costs were also appro- reliability, unfamiliarity with space systems, priate. The laser system might be of interest to and institutional questions. Only demonstra- the utilities if it could be used to repower exist- tion, and successful experience with an opera- ing thermal facilities. The suggested unit size tional SPS over several years, would assure the of the laser system (500 to 1,000 MW) would fit utilities that it is a viable technology for their welI into the present size mix of terrestrial use. If the microwave systems were as reliable powerplants. A mirror system with its highly *See ch 9, The Irnpl;cat;ons for the Utility /ndustry section centralized, energy producing facility (10 to 34 ● Solar Power Satellites

100 GW) would be too large for the present 21 and September 21) when the Earth’s size mix, but would offer the potential for shadow falls across the satellite, a refer- some flexibility in energy production. Direct ence system satellite would suffer power electricity and hydrogen generation are both interruption. A number of satellites would possible in a SOLARES-type energy park. How- be eclipsed at one time. The rate at which ever, because the SPS would be an integral the eclipsing occurs would cause the SPS part of the utility grid, it would impose certain power to fall at a rate of about 20 percent constraints on grid dispatch management. The per minute, much faster than the utility physical requirements of the rest of the utility grids are expected to be able to respond. grid would in turn impose constraints on the This could be alleviated by shutting the design of SPS. Integrating SPS into the grid in- satellite down slowly in advance of the volves several difficult system problems. shadow, with a consequent extra small loss of SPS power for the period, or by Microwave Transmission. — including buffer storage as suggested ● Stability. Because a microwave SPS is an above. If daily load curves maintain their electronic system, not a mechanical one, current shape, the eclipse would occur any power fluctuations due to beam- near the daily minimum (local midnight), pointing errors or to large-scale compo- necessitating less backup capacity than nent failure would be rapid (the order of a wouId otherwise be the case. second or less). The rest of the grid would In principle, SPS could be designed to only be able to respond relatively slowly follow the daily load, but because of its (minutes), creating difficulties in control- high capital costs it would be uneco- ling the frequency of current and overall nomical to do so. It is designed to deliver power levels in the grid. The importance continuous, baseload power. Hence the of this difficulty is directly dependent on burden of following any shifts in load the size of the SPS contribution. The would be placed on conventional terres- smaller the output from a satellite- trial intermediate load units in the utility rectenna combination, the easier it will be system. to control. Some, if not all of this draw- ● Microwave beam positional errors. The back of the microwave system could be beam could be centered on the rectenna alleviated by including short-term battery by means of a pilot beam directed to- storage to act as a buffer between the SPS wards the satellite antenna from the rectenna output and the grid. The stability center of the rectenna. Because the signal of the grid would not then depend on the would take about 0.2 seconds to sense a stability of the microwave mode of trans- position error and correct the pointing of mission. However, buffer storage would the beam, the antenna output would be increase system costs. The optimum subject to a potential frequency variation amount of storage that might be needed of about 5Hz (5 cycles/see). Power varia- has not been determined, but cost esti- tions of tens of megawatts from this mates range from 0.5 to 5 percent of the source could make utility grid manage total system costs. ment extremely difficult. Weather fronts Load following and variations of SPS pow- could adversely affect the position of the er. The rectenna output would vary sea- beam, but the resultant power variation sonally depending on the distance of the would be slow. Again, buffer storage Earth from the Sun. The amount of the could be used to alleviate these dif- variation, and the rate at which SPS power ficulties. changes, would in principle pose no technical problem for the grid. Because the difficulties posed by each of Because any satellite that lies in a geo- the above factors increase with size, the stationary orbit experiences eclipses (1 to utilities might not find the single 5,000-MW 72 minutes) around the equinoxes (March unit proposed by the reference system accept- Ch. 3—Issues and Findings ● 35

able even in the future. Although nuclear, fu- parks capable of producing more than 100 sion, or coal energy parks having about 5,000 GW. Smaller parks of 10 GW might also MW total capacity have been proposed, they be possible. Even the relatively smaller would be composed of several smaller units, parks would necessitate major changes in each of which are only about 1,000-MW capac- current utility operation and load man- ity. In addition, in planning for overall system agement. Among other changes, such reliability, utilities generally use the criterion parks would necessitate building an exten- that no single unit in the system can account sive new network of major transmission for more than 10 to 15 percent of the total lines to distribute electrical power from system. Thus, in order to place a 5,000-MW remote receiving areas to end-users. unit in the grid, the grid should have a total In principle, all of the technical problems system capacity of 33,000 to 50,000 MW. At for the different systems are resolvable at current rates of electrical growth (3.2 percent some cost. However, they would require con- per year), only the Tennessee Valley Authority siderable further study and testing as well as a (TVA), the country’s largest utility, will have a close look at the system economics. grid large enough to accommodate a 5,000- MW SPS in 2000. TVA currently has a capacity of 23,000 MW, but it has stopped construction Nontechnical Considerations on several new powerplants because of slower In addition to the technical difficulties that demand growth. A national power grid might SPS can be expected to face, there are a alleviate the problem of utility grids being too number of potential institutional barriers to small to accommodate a 5,000-MW SPS. SPS acceptance by U.S. utilities: Laser Transmission.— From the utilities’ per- ● SP5 as a space system. The current utility spective, the most serious difficulty facing management and regulatory infrastruc- laser transmission is absorption by clouds. ture is much more receptive to the ter- Although in a few locations in the country it restrial renewable or inexhaustible op- appears to be technically possible to switch tions— breeder reactor and fusion for from a cloud covered area to one that is cloud- baseload, and solar thermal and solar free, utilities would have little incentive to photovoltaic for intermediate and peak- construct the extra facilities to accommodate ing loads. such switching unless the economic benefits ● Regulatory framework. Utilities are cur- were commensurate with the expense of the rently regulated on a State or local basis. extra facilities. In general, the various sites are SPS could be expected to hasten the move unlikely to be all in the same service area, fur- towards greater centralization of the reg- ther complicating the ability of the utility to ulatory process (i.e. Federal level). A follow the load. SOLARES-type SPS, because of its large Mirror Reflection. — centralized energy parks, would make a ● Reflection of sunlight from space suffers high degree of centralization mandatory. from the same disadvantage as that of the However, other SPS modes may also lead laser option: the reflected beam could to more centralized regulation, particu- easily be degraded or occluded by cloud larly if the SPS were constructed and man- cover. it has been suggested that the addi- aged by a federally chartered monopoly tional radiant energy might be enough to (see Ownership and Finance) or Govern- dissipate clouds, but this might have ment agency. detrimental environmental effects and Nuclear powerplants are currently regu- alter weather patterns over a wide region lated at the Federal and State level for around the energy park. health, safety, and environmental im- ● As conceived in the “baseline” case, the pacts. However, their effect on the rate mirror system would require large energy structure is regulated at the State and 36 . Solar Power Satellites

local level. An SPS corporation might lead to international law that requires national to Federal involvement in setting rates for governments to bear the responsibility for power as well as regulating SPS technol- space activities, even when carried out by ogy. The utilities and local regulatory nongovernmental entities, some degree of agencies could be expected to resist any Federal supervision and involvement will pressures toward greater Federal involve- be required in any case. ment in what has traditionally been their R&D and operating phases. Raising private province. capital would be especially difficult during the research, development, and dem- Ownership and Finance onstration phase. A successful prototype demonstration would probably be nec- Electric utilities currently face a serious essary to attract private investment. If SPS problem raising the capital necessary to install is judged to be a feasible energy option, new generating capacity. Because of this, and prototype development is likely to require because they lack launch and space construc- Federal funding, perhaps via taxes, similar tion capability, they are unlikely to own or to the Interstate Highway System trust operate the space segment of an SPS system fund, or through “Space Bonds.” After directly; they could more easily be responsible that, it is likely that Government loans or for the ground receivers. This raises the ques- guarantees would be required, at a mini- tion of how domestic SPSs would be financed mum. At some stage the technology could and managed. be turned over to the private sector. In- stances of such practices have included The central issues are: 1 ) the degree and kind nuclear reactors, first developed for mili- of government involvement; and 2) how to dif- tary use in submarines; and telecommuni- ferentiate between the R&D and construction/ cations technology, funded by NASA and operation phases. then turned over to Comsat and commer- ● Government involvement. The arguments cial carriers. Clarification of current pat- for Government financing and ownership ent provisions for NASA and other Gov- wouId be that the high fronnt-end costs and ernment research contracts would facili- high-risk long pay-back times inhibit pri- tate such transfers. Upcoming examples vate sector investment, and that lack of that should be examined for their appli- competition would necessitate Govern- cability to SPS are the Space Shuttle, ment ownership. Certain aspects of TVA which has been developed by NASA but or NASA could provide possible guidance may eventually be turned over to private for SPS ownership and operation. enterprise, due to restrictions on NASA On the other hand, it can be argued that operation of commercial ventures; the direct Government involvement is con- newly established U.S. Synfuels Corp., trary to American preference for private which is intended to provide money for a enterprise, that centralized control would variety of private synthetic fuels ventures; lead to inefficiencies, and that U.S. Gov- and the European Space Agency’s (ESA) ernment ownership would make military Ariane launcher, which will be operated participation far more likely. Further- by a private consortium called Ariane- more, it is feared that Government invest- space. Private joint ventures, such as ment in SPS would drain resources from Satellite Business Systems or the Alaska other energy technologies that need pipeline consortium, are another possible Federal support. A Government-chartered way to establish a “Solarsat” Corp. for the but privately owned and operated com- construction and operating phases. pany similar to Comsat, or a regulated A combination of the suggested mod- private monopoly such as AT&T, might be els, involving different degrees of Govern- preferred. Since the United States is party ment and private financing, may be more Ch. 3—Issues and Findings ● 37

feasible than any of the specific models the ability of an SPS organization to at- mentioned. Providing for a smooth transi- tract foreign capital and to involve for- tion between public and private invest- eign participants at early stages of devel- ment phases would be an important con- opment. (See International Implications.) cern. A critical consideration should be

INTERNATIONAL IMPLICATIONS

What are the international implications of stant or rise only SIightly over the next 30 years. solar power satellites?* On a global scale, this might indicate a rise less Development and construction of an SPS than that predicted by IIASA. Meeting this de- system would necessarily involve a number of mand will be particularly difficult in energy- international dimensions. At a minimum, cur- scarce areas such as Western Europe, Japan, rent and future international treaties and and much of Latin America, Africa, and South agreements, especially those dealing with the Asia. Countries in these regions will be allocation of the electromagnetic spectrum, especially interested in SPS development. would require consultation with foreign states Noneconomic Impact. -The noneconomic and multinational organizations. Beyond this, effects of SPS would influence the decisions of there may be good reasons to consider an ac- the major space powers, the United States and tive multilateral regime to regulate, build, the U.S.S.R. The prestige of such a major space and/or operate the SPS. and energy accomplishment would be consid- International organizations, multinational erable. The military advantages of high-capac- corporations, and domestic interest groups will ity launch vehicles and a large energy-produc- all be involved in SPS decisions. However, due ing platform in high orbit would be significant, to the SPS’s cost, benefits, and military/foreign even if SPS were not used for direct military policy impacts, which would directly affect purposes. the vital national interests of other nations in- The United States and the U.S.S.R. both volved, such decisions will ultimately be made have extensive conventional energy sources– at the national level by political leaders. oil, coal, oil shale, and uranium. Thus, neither Economic lmpact.– If successful, the SPS country can be expected to develop an SPS promises to deliver significant amounts of unilaterally unless unpredictable obstacles to electricity y. Estimates of future global elec- the use of coal and/or nuclear power develop. tricity demand by the International Institute SPS is therefore likely to be pursued in con- for Applied Systems Analysis (IIASA) indicate junction with foreign partners who contribute that, even with low rates of economic growth, capital and expertise and buy completed satel- electricity usage will increase by a factor of 4 lites. Both Western Europe and Japan, who over the next 50 years. Regional variations in have extensive space programs and a history of growth rates will be considerable, with cooperation with the United States, would be developed countries increasing at a much probable partners. Soviet secrecy and military slower rate than developing ones. Recent domination of their space program makes in- studies for the United States that take into ac- ternational cooperation on their part unlikely. count marked reductions in usage rates, such International Cooperation.– Experience with as the National Academy of Sciences’ Energy multilateral organizations suggests that estab- in Transition 1985-2010 indicate that demand in the developed countries may remain con- I The global estimates cited in Energy in Transition, however, are similar to I IASA’S; a rise of three to five times in electricity consumption by 2010. See Energy in Transition, National *See ch. 7. Academy of Sciences, 1979, p. 626. 38 . Solar Power Satellites

Iishing and running a successful international development may be difficult or politically im- venture would be difficult. Reconciling the dif- possible; the precedent set by the uncom- ferent interests of the participants regarding pleted Law of the Sea negotiations should be overall system design, decision making, and carefulIy considered. allocation of contracts and financial returns Military Impact. – The military uses of an SPS, would be time-consuming and might compro- especially for directed-energy weaponry, mise timely and efficient results. The example would be restricted by the 1972 Anti-Ballistic of Intelsat suggests the importance of strong Missile (ABM) Treaty and by provisions in the national support by interested parties, of 1967 Treaty on Principles Governing the Ac- independent corporate management, and a tivities of States in the Exploration and Use of profit-incentive. However, it is unlikely that an Outer Space banning weapons of “mass agency modeled on Intel sat could be dupli- destruction” in orbit. Although SPS would not cated today for SPS. In particular, the role of lend itself to efficient use as a weapons- LDCs would be greater and could be disruptive system, * objections to the SPS on military unless North-South conflicts can be kept from grounds, and demands for inspection and/or dominating day-to-day decisions. Strong redesign to preclude military uses, can be ex- leadership by the United States and the Orga- pected. Multilateral development would alle- nization of Economic Cooperative Devel- viate many such problems. opment partners would be required to maintain an effective program. Foreign Interests.—To date, space agencies and private firms in foreign countries such as International Law.– International law cur- England, France, West Germany, and Japan, rently requires allocation of satellite frequencies and geostationary positions by the inter- along with ESA, have expressed interest in SPS. Most foreign studies have focused on regional national Telecommunication Union (ITU). If applications; technical and operational studies SPS were to interfere with global communications, this could be a major obstacle to gaining have been done almost exclusively in the ITU approval. ownership and control of the United States. Soviet interest has been expressed for several years, with several tech- geostationary orbit has not been completely resolved, and attempts by equatorial states to nical papers published, but no details are known. Third World interest has been informal claim sovereignty over it could hamper devel- and cautiously favorable. Future discussion at opment of any geostationary SPS. The proposed Moon Treaty, which calIs for an interna- the United Nation’s Committee on the Peace- ful Uses of Outer Space and other international regime based on the principle of the tional bodies will be forthcoming. Any further Common Heritage of Mankind, provides a precedent for international control over space U.S.-sponsored study of SPSs must take into resources, and may affect plans to construct account international participation in SPS development, and demand for SPS power, in SPS from lunar materials. In each of these order to evaluate properly the feasibility of cases it can be expected that future LDCs will SPS programs. seek to gain leverage over any SPS regime by controlling access to space. Accommodating ——. LDC interests in a manner compatible with SPS ‘See ch 7, Military Uses of SPS section

NATIONAL SECURITY IMPLICATIONS

What are the national security implications The military importance of SPS would derive of SPS?* from its very large size, its geostationary orbital position (for certain designs), and its ability to provide tremendous amounts of power. *For extended discussion see ch, 7 Aside from the important result of reducing Ch. 3—Issues and Findings ● 39

the user state’s dependence on imported The use of nuclear weapons outside of a ma- energy, SPS would be strategically significant jor nuclear exchange would carry great dan- as a target, as the catalyst for new space gers of escalation. Any attack, nuclear or con- transportation and construction capabilities, ventional, would depend on perceptions of and as a possible weapons-system. whether SPS is considered part of national territory and how leaders would react to such a Vulnerability. –A full-scale SPS system provocation. The analogy to ships on the high wouId constitute a high-value target for enemy sea suggests that an SPS in orbit might be con- action. Whether an SPS would in fact be sidered fair game even short of full-scale war. targeted in the event of hostilities will depend Attacks on SPS would also be affected by above all on how crucial it is to a country’s whether the SPS was manned; destroying an electrical supply. Can SPS power be made up unmanned craft might be undertaken as a rela- from other sources? Is the attacker vulnerable tively unprovocative demonstration of will. At to a counter-attack in kind? Best estimates are present, neither the United States nor the that an SPS system would be unlikely to con- U.S.S.R. has the ability to attack objects in stitute more than 10 to 20 percent of total geosynchronous orbit, but both are working on generating capacity, in the countries that use various antisatellite devices and there appear SPS, over the next 50 years. Holding SPS to this to be no insurmountable obstacles to their percent would make it possible to replace SPS development. power from conventional reserve capacity. However, usage could be much higher in spe- Defense of space craft is possible through: cific regions or industries. A widespread na- 1) maneuverability, 2) hardening, and 3) anti- tional grid could alleviate the threat of SPS missile defenses. outages. In general, SPS would be no more The SPS would be too large and fragile to VuInerable than other major energy systems. evade attack. Hardening against explosives or SPSs could be attacked in a number of ways: EMP bursts would add significantly to weight 1) by ground-launched missiles carrying nu- and costs, and could not be effective against a clear or conventional warheads, 2) by orbiting determined attack. Stationing missile or satel- antisatellite platforms, 3) by ground- or space- lite defenses on a geostationary SPS, whether based directed-energy weapons, 4) by strewing directed-energy weapons or antimissile mis- debris in the satellite’s path, and 5) by inter- siles, would be feasible due to the power fering with or redirecting the SPS’s energy generated by the SPS and its position at the top transmission beam. of a 35,800-km “gravity well”. However, such weapons would have unavoidable offensive The large size of most SPS options would capabilities and would therefore invite attack. make it difficuIt for conventional explosives to Defense of civilian SPSs could probably be do serious damage. Lasers would likely be best done by independent military forces, on more effective. Strewing debris in geosyn- the ground or in space, rather than by turning chronous orbit would destroy a reference the SPS itself into a space-fortress. system SPS, but also affect many other targets, including friendly and neutral spacecraft. Receiving antennas or (for the mirror- Beam interference would be less damaging system) PV ‘parks’ would make unattractive and would require special preparation to pro- targets due to their large size and redundancy; tect against. Nuclear weapons could damage they would certainly be no more vulnerable SPSs by direct blast, and also by the electro- than other generating facilities. It should be magnetic pulse (EMP) effect, which might noted that the SOLARES system could con- overload the satellite’s electrical systems — a tinue to produce power, albeit at approximate- large (1 megaton or more) nuclear explosion ly one-fifth rated capacity, by operating on could damage a photovoltaic SPS at ranges up ambient sunlight even if the space mirror to hundreds of kilometers. system were destroyed. 40 . Solar Power Satellites

Military Uses. –The military usefulness of an Such provisions might be needed even if SPS SPS stems from: 1) the launchers and other fa- would not be militarily useful, but was never- cilities used to construct the satellite portion; theless perceived to be a military or political 2) the energy beams used by the SPS to trans- threat. mit power; and 3) its strategic orbital location. Using an SPS directly against targets on the HLLVS or other transportation and construc- ground would ease tracking requirements. tion systems would be perhaps the most direct High-energy lasers (H EL) or particle-beams military benefit of SPS. These could be used by could conceivably be used to destroy quickly the military to build large space platforms for tactical targets such as ships, planes, or oil communications, surveillance, or weaponry. refineries without jeopardizing one’s own per- Such activities might be disguised by being sonnel or risking the use of nuclear weapons. carried out during SPS construction, but it is However, SPS lasers used for energy transmis- unlikely that they could escape detection by sion would probably not make effective interested parties. Development of such sys- weapons without considerable modification. tems would be most important, and destabiliz- SPS could also be used to supply electrical ing, in providing a “break-out” capacity for power to military units in remote areas, and rapid emergency deployment of military satel- perhaps even directly to ships or planes. lites by fleets of SPS construction vehicles. Laser beams built as part of SPS, or more SPS could serve as a platform for certain militarily efficient weapons placed on the SPS surveillance and communications needs. Be- but not used in transmitting electricity, could cause of its power, it might be especially be used as strategic weapons. In recent years suited for conducting jamming and electronic both the United States and the U.S.S.R. have warfare operations. undertaken large programs to develop directed-energy weapons for use against satel- SPS platforms, because of their size and lites and/or international ballistic missiles facilities, would be likely to serve as multipur- pose space bases similar to major seaports. If (ICBMs). However, a geostationary SPS is 35,800 kilometers distant from low-flying military units used SPS for resupply or rest and ICBMs. This distance complicates tracking and recreation, it might be difficult to separate requires very high beam intensities. Much military from civilian uses, or to convince out- greater effectiveness can be achieved by side observers that SPS was not a military weapons placed in lower orbits. However, a threat. geostationary SPS could play a role in supply- Any such direct uses of SPS would be deter- ing power to remotely located directed-energy mined by the way in which future SPSs are platforms. A laser SPS in low Sun-synchronous built and managed. Construction by an inde- orbit, of course, would represent a much pendent multinational enterprise would re- greater military potential than one in geosyn- duce any state’s ability to use an SPS for mili- chronous orbit. tary purposes; conversely, unilateral devel- Use of SPS, even indirectly, for ABM pur- opment would enhance it. Use of SPSs as poses is currently prohibited by the 1972 ABM weapons platforms by future superpowers Treaty. A militarily effective SPS would be a would invite considerable foreign criticism, major factor in strategic planning and would especially if such attempts interfered with likely be a subject of arms-control negotiations their electricity-generation function. A sudden between interested states. Provisions for direct diversion of SPS power to the military in time inspection, or design specifications to reduce of crisis could lead to domestic and/or foreign an SPS’s military usefulness, could be negoti- electricity shortages, resulting in legal or ated to reduce the various threats it poses. diplomatic protests. Ch. 3—Issues and Findings ● 41

PUBLIC ISSUES

The SPS debate: what are the issues arising in plex, and that it poses greater environmental the public arena?* and military risks while precluding local decisionmaking. Many opponents also maintain While public awareness of SPS is growing, that all future energy demand can be easily most discussion has been confined to a small met with existing and future terrestrial energy number of public interest groups and profes- technologies; there is little need to develop sional societies. In general, many of the in- SPS, especially in view of the formidable costs dividuals and groups who support the develop- to initiate the technology and the highly uncer- ment of SPS also advocate a vigorous space tain cost of the product. The Citizen’s Energy program. The L-5 Society has been a particu- Project (CEP) has been an active lobbyist larly vocal SPS supporter and views the against Government funding of SPS and has satelIite system as an important stepping-stone coordinated the Coalition Against Satellite in the colonization of space, a goal to which Power Systems, a network of solar and environ- the society is dedicated. The SUNSAT Energy mental organizations. Objections to SPS have Council, a group formed to promote interest in also been raised by individuals in the profes- SPS, believes that it is one of the most promis- sional astronomy and space science coming options available for meeting future global munities who see SPS as a threat to the funding energy and resource needs. Professional asso- and practice of their respective sciences. In the ciations such as the American Institute of future, it is conceivable that antinuclear, anti- Aeronautics and Astronautics (AIAA) and the military and tax groups could also join the op- Institute of Electrical and Electronics Engi- position. neers (1 E E E), have supported continued research and evaluation of the concept. Public opinion about SPS can be influenced by a multitude of factors; concerns articulated Many opponents of SPS are concerned that today may not be as important in the future. In it wouId drain resources from the development addition, in much of the current public discus- of terrestrial solar technologies. The Solar Lob- sion, SPS is treated as a U.S. system alone. If by and other public interest groups argue that SPS were to be developed on an international compared to these ground-based solar options, basis, the flavor of present opinion could SPS is inordinately large, expensive, and com- change. Currently, debate about SPS focuses on the question of R&D funding. This and ‘See ch 9, Issues Arising in the Public Arena section other issues are highlighted in table 2.

ENVIRONMENT AND HEALTH

How would SPS affect human health and the effects which are poorly understood at pres- environment?* ent. The resolution of the uncertainties associated with these effects is critical to the As an energy system operating both in space assessment of the environmental acceptability and on Earth, SPS involves some rather diverse of SPS. More research is needed to understand and unique environmental issues (see table 3). and quantify these impacts and to investigate While one advantage of SPS is that it would modified system designs that would minimize avoid many of the environmental risks typi- environmental risks. At present, there are three cally related to conventional energy options major areas of concern. such as nuclear and coal, it would also generate some unconventional environmental 1. Bioeffects of Electromagnetic Radiation.— The effects of exposure to SPS power trans- *See ch. 8. mission and high-voltage transmission lines

83-316 0 - 81 - 4 42 . Solar Power Satellites

Table 2.—Major Issues Arising in SPS Debatea

Pro R&D funding . SPS is a promising energy option ● SPS is a very high-risk, unattractive technology . The Nation should keep as many energy options open as ● Other more viable and preferable energy options exist to meet our possible future energy demand ● An SPS R&D program is the only means of evaluating the merit ● SPS would drain resources from other programs, especially ter- of SPS relative to other energy technologies restrial solar technologies and the space sciences ● SPS R&D will yield spinoffs to other programs No matter what the result of R&D, bureaucratic inertia will carry a Government program too far cost ● SPS is likely to be cost competitive in the energy market ● SPS is unlikely to be cost competitive without Government subsidy . Cost to taxpayer is for R&D onIy and accounts for smalI portion ● Like the nuclear industry, SPS would probably require ongoing of total cost; private sector and/or other nations will invest in pro- Government commitment duction and maintenance ● Projected costs are probably underestimated considerably . SPS will produce economic spinoffs ● The amount of energy supplied by SPS does not justify the cost

Environment, health and safety ● ● SPS is potentialIy less harsh on the environment than other SPS risks to humans and the environment are potentially greater energy technologies, especially coal than those associated with terrestrial solar technologies ● Major concerns include: health hazards of power transmission and high-voltage transmission lines, land use, electromagnetic interference, upper atmosphere effects, and “skylab syndrome” Space ● Space is the optimum place to harvest sunlight and other ● SPS is an aerospace boondoggle; there are better routes to space resources industrialization and exploration than SPS ● SPS could be an important component or focus for a space ● SPS is an energy system and should not be justified on the basis program of its applicability to space projects . SPS could lay the groundwork for space industrialization and/or colonization . SPS would produce spinoffs from R&D and hardware to other space and terrestrial programs International considerations ● ● One of the most attractive characteristics of SPS is its potential SPS could represent a form of U.S. of industrial nations’ “energy for international cooperation and ownership imperialism”; it is not suitable for LDCs . SPS can contribute significantly to the global energy supply ● Ownership of SPS by multinational corporations would centralize . SPS is one of the few options for Europe and Japan and is well- power -suited to meet the energy and resource needs of developing nations ● An international SPS wouId reduce concerns about adverse military implications

Military implications ● The vulnerability of SPS is comparable to other energy systems ● Spinoffs to the military from R&D and hardware would be signifi- ● SPS has poor weapons potential cant and undesirable • As a civilian program, SPS would create little military spinoffs ● Vulnerability and weapons potential are of concern

Centralization and scale ● Future energy needs include large as well as small-scale supply ● SPS would augment and necessitate a centralized infrastructure technologies; urban centers and industry especially cannot be and reduce local control, ownership, and participation in decision- powered by small-scale systems alone making . SPS would fit easily into an already centralized grid ● The incremental risk of investing in SPS development is unacceptably high Future energy demand ● Future electricity demand will be much higher than today ● Future electricity demand could be comparable to or only slightly ● High energy consumption is required for economic growth higher than today’s with conservation ● ● SPS as one of a number of future electricity sources can con- The standard of living can be maintained with a lower rate of energy consumption tribute significantly to energy needs ● . Even if domestic demand for SPS is low, there is a global need There is little need for SPS; demand can be met easily by existing for SPS technologies and conservation ● By investing in SPS development, we are guaranteeing high energy consumption, because the costs of development would be so great arguments mainly focus on the SPS reference sYstem SOURCE: Office of Technology Assessment. Ch. 3—Issues and Findings ● 43

Table 3.—Summary of SPS Environmental Impacts

System component Occupational health characteristics Environmental impact Public health and safety and safety Power transmission b b Microwave — Ionospheric heating could — Effects of Iow-level —Higher risk than for disrupt telecommunications. chronic exposure to micro- public; protective Maximum tolerable power waves are unknown. clothing required for density is not known. — Psychological effects of terrestrial worker. Effects in the upper microwave beam as weapon. —Accidental exposure to ionosphere are not known. —Adverse aesthetic effects high-intensity beam in —Tropospheric heating could on appearance of night sky. space potentially severe result in minor weather but no data. modification. — bEcosystem: microwave bioeffects (on plants, animals, and airborne biota) largely unknown; reflected light effects unknown. — bpotential interference with satellite communications, terrestrial communications, radar, radio, and optical astronomy.

Lasers —Tropospheric heating could —Ocular hazard? —Ocular and safety modify weather and spread —Psychological effects of hazard? the beam. laser as weapon are —Ecosystem: beam may possible. incinerate birds and —Adverse aesthetic effects vegetation. on appearance of night b — potential interference sky are possible. with optical astronomy, some interference with radio astronomy.

Mirrors — bTropospheric heating —Ocular hazard? —Ocular hazard? could modify weather. —Psychological effect of —Ecosystem: effect of 24- 24-hr sunlight. hr Iight on growing. — b Adverse a esthetic effects cycles of plants and cir- on appearance of night cadian rhythms of animals. sky are possible. — bpotential interference wit h optical astronomy.

Transportation and space operation Launch and recovery —Ground cloud might pollute —Noise (sonic boom) may — bSpace worker’s hazards: air and water and cause exceed EPA guidelines. ionizing radiation possible weather modi- —Ground cloud might affect (potentially severe) HLLV fication; acid rain air quality; acid rain weightlessness, life PLV probably negligible. probably negligible. support failure, long COTV — bWater vapor and other —Accidents-catastrophic stay in space, POTV launch effluents could explosion near launch construction accidents deplete ionosphere and site, vehicle crash, toxic psychological stress, enhance airglow. Result- materials. acceleration. ant disruption of com- —Terrestrial worker’s munications and satellite hazards: noise, trans- surveillance potentialy portation accidents. important, but uncertain. — bpossible formation of noctilucent clouds in stratosphere and mesosphere; effects on climate are not known. 44 ● Solar Power Satellites

Table 3.—Summary of SPS Environmental Impacts—Continued

Manufacturing —Measurable increase of —Measurable increase of —Toxic materials exposure. air and water pollution. air and water pollution. —Noise. —Solid wastes. —Solid wastes. —Exposure to toxic materials.

Construction —Measurable Iand —Measurable land —Noise. disturbance. disturbance. —Measurable local —Measurable local increase —Measurable local increase increase of air and water of air and water pollution. of air and water pollution. pollution. —Accidents.

b b Receiving antenna — Land use and siting. — Land use—reduced — Waste heat. —Waste heat and surface property value, aesthetics, roughness could modify vulnerability (less land weather. for solid-state, laser opt ions; more for reference and mirrors).

b b High-voltage — Land use and siting. — bExposure to high intensity — Exposure to high transmission lines — bEcosystem: bioeffects Of EM fields—effects intensity EM fields— (not unique to SPS) powerlines uncertain. uncertain. effects uncertain. almpacts based on SPS systems as currently defined ancl do not account for offshore receivers or poss!ble miti9atin9 sYstem modifications. bResearch priority. SOURCE: Office of Technology Assessment. Ch. 3—Issues and Findings ● 45

(HVTL) on humans, animals, and plants are exposure limits. Research is needed to deter- highly uncertain. The existing data base is in- mine more precisely the expected dose rates, complete, often contradictory and not directly the types and energies of ionizing particles, applicable to SPS. While the thermal effects of and the effectiveness rate of various types and microwave radiation (i. e., heating) are well- thicknesses of shielding. The results will deter- understood, research is critically needed to mine the number of spaceworkers, the dura- study the consequences of chronic exposure to tion of the stay, the mass needed in orbit (for low-level microwaves such as might be ex- shielding), and space suit and system designs. perienced by workers or the public outside of All of these impacts may strongly affect SPS the receiver site. The biological systems that costs and feasibility. may be most susceptible to microwaves include the immunological, hematological For SPS systems other than the microwave (blood), reproductive, and central nervous sys- designs, very little assessment of the health tems. The DOE SPS assessment has sponsored and safety effects has been conducted. The three studies of the effects of low-level micro- power density of a focused laser system beam waves on bees, birds, and small mammals. No could be sufficiently great to incinerate some significant effects have been observed, but the biological matter. Outside the beam, scattered experiments are far from complete. More re- laser light could constitute an ocular and skin search is vitally needed to expand the experi- hazard. More study would be needed to quan- mental and clinical data base, and to improve tify risks, define possible safety measures and theories which may facilitate the extrapolation explore the effects of long-term exposure to from animal studies to assessments of human low-level laser light. health hazards. The light delivered to Earth by the mirror It appears that the United States will estab- system, even in combination with the ambient lish a microwave standard in the near future daylight, would never exceed that in the desert that is more stringent than the present occupa- at high noon. The health impacts that might be tional 10.0 mW/cm2 voluntary guideline (the adverse include psychological and physiologi- new occupational standard at 2.45 GHz will cal effects of 24 hour per day sunlight and probably be 5.0 mW/cm2), thereby approach- possible ocular damage from viewing the mir- ing the standards in other countries (e. g., rors, expecialIy through binoculars. Canada: population —1.0 mW/cm2, occupa- 2 2. Effects on the Upper Atmosphere.– Atmos- tional —5.0 mW/cm ; U. S. S. R.: population— 2 2 pheric effects result from two sources: heating 0.001 mW/cm , occupational —0.01 mW/cm ). by the power transmission beam and the emis- This does not have an immediate impact on sion of launch vehicle effluents. While the SPS Iand use for the reference system, since it 2 most significant effect of the laser and mirror is designed to produce less than 1.0 mW/cm at systems is probably weather modification due the rectenna boundary and less than 0.1 mW/ 2 to tropospheric heating, ionospheric heating is cm outside the rectenna boundary. Neverthe- most important for the microwave systems less, establishing population standards that are operating at 2.45 GHz. Of most concern is more stringent couId mean more land for each disruption of telecommunications and surveil- buffer zone and could affect system design lance systems from perturbations of the iono- (power density and beam taper) as well as sphere. Experiments indicate that the effects public opinion. on telecommunications of heating the lower With respect to spaceworkers, exposure to ionosphere are negligible for the systems ionizing radiation (including that from the tested. As a result, a few researchers have sug- radiation belts, galactic cosmic rays, and solar gested that microwave power densities of up flares) would be a health hazard unless steps to 40 to 50 mW/cm2, or two times the level are taken in future planning to minimize dose. assumed for the reference design, could be Studies are needed to determine acceptable used before significant heating would occur. 46 ● Solar Power Satellites

The largest uncertainty is related to heating and quantify the above impacts under SPS and nonlinear interactions in the upper iono- conditions. In addition mitigating steps such as sphere. To investigate the heating effects in trajectory control, alternate space vehicle this region, more powerful heating facilities design, and the mining of lunar materials need would be required. to be assessed. Atmospheric studies would play a major role in the choice of frequency The atmospheric effects resulting from the for power transmission. emission of rocket effluents from SPS space vehicles are of concern because of the unprecedented magnitude and frequency of the 3. Land Use and Receiver Siting.– Receiver projected SPS launches. In the magnetosphere, siting could be a major issue for each of the construction of the SPS reference system as land-based SPS systems. Offshore siting and presently designed would lead to a dramatic multiple use siting might each alleviate some increase in the naturally occurring abundance of the difficulties associated with dedicated of argon ions (from the electric propulsion land-based receivers, but require further study. system proposed for orbital transfer) and There are two components to the siting issue: hydrogen atoms. While several possible effects technical and political. Tradeoffs must be have been identified, including enhanced air- made between a number of technical criteria: glow and Van Allen belt radiation, and altered 1) finding geographically and meteorologically atmospheric electricity and weather, the likeli- suitable areas; 2) finding sparsely populated hood and severity of these effects are highly areas; 3) keeping down the cost of power trans- uncertain. mission lines and transportation to the construction site; 4) siting as close to the Equator The injection of water vapor at lower alti- as possible (for GEO systems) so as to keep the tudes would significantly increase the water north-south dimension of the receiver rea- content relative to natural levels. One possible sonably small; 5) coordinating receiver sites consequence is an increase in the upward flux with utility grids and the regional need for of hydrogen atoms through the thermosphere. electricity; 6) the cost of land; and 7) ensuring Another consequence of increasing the con- that the receivers are sited away from critical centration of water in the upper atmosphere and sensitive facilities that might suffer from might be the formation of noctilucent clouds electromagnetic interference from SPS, e.g., in the mesosphere. While global climatic ef- military, communications, and nuclear power fects of these clouds appear unlikely, uncer- installations. In addition, for the reference and tainties remain. SOLARES systems, as presently designed, large The injection of rocket exhaust, particularly contiguous plots of land would have to be water vapor, into the ionosphere could lead to located and totally dedicated to one use (table the depletion of large areas of the ionosphere. 4). The laser options might require less land These “ionospheric holes” could degrade tele- area per site, but a greater number of sites to communication systems that rely on the iono- deliver the comparable amount of power. sphere. While the uncertainties are greatest for the lower ionosphere, experiments are needed It is clear that the choice of frequency, to test more adequately telecommunications ionospheric heating limits, and radiation impacts and to improve our theoretical under- standards could have an impact on the land re- standing of chemical-electrical interactions quirements. Further study is needed to under- throughout the ionosphere. stand fully the environmental and economic In the troposphere, ground clouds generated impacts of a receiver system on candidate sites during liftoff could modify local weather and and to determine if enough sites can be located to satisfy the technical requirements. air quality on a short-term basis. In addition the plausibility of multiple uses Additional experiments and improved at- (e.g., agriculture or aquiculture), offshore mospheric theory are needed to understand siting (especially for land-scarce areas such as Ch. 3—Issues and Findings ● 47

Table 4.—SPS Systems Land Use Number of sites Total land area(km2) SPS system km2/site km2/1,OOOMW for 300,000 MW for 300,000 MW m2/MW-yr Reference ...... 174 35.0 60 10,400 1,233 b Solid statec ...... 50 33.0 180 9,000 1,163 b Laser Id...... 0 1.2 600 360 42-51e Laser lId...... 40 80.0 600 24,000 2,819-3,382 e Mirror I ...... 1,000 -29 2,200 261-313 e Mirror Ilf...... 100 9.6 30 2,880 338-406 e For comparison Washington...... 174.0 New York City...... 950.0 Chicago...... 518.0 aR~~t~nna at 34. latitude ~over~ a 117 km, e(lipitical area, Mi~r~~ave power density at edge of rectenna is 1.(J mw/cm2, If an exclusion boundary is set at 0.1 mW/Cm2, then the total land per site is approximately 174 km2. J. B. Blackburn, Sate//ire Power System (SPS) Mapping of Exc/usion Areas for Rectenna Sites, DOE/NASA Report HCP/R-4024-10, October 1978 does not include land for mining or fuel transport. bThe values for the reference and solid-state designs assume a 30-year lifetime and a caPacitY factor of 0.9 cThe solid-state sandwich design is described in G. M. Hanley et al., “Satellite Power Systems (SPS) Concept Definition Study, ” First Performance Review, Rockwell international Report No. SSD79-0163, NASA MSFC Contract NAS8-32475, October 10, 1979.

dLaser 1 and Laser II are two laser systems considered by DOE Both deliver the same amount of power but the beam of Laser I is more narrow (and hence rllore intenSe) than that of Laser Il. See C. Bain, Potential of Laser for SPS Power Transmission, October 1978, Department of Energy, HCPIR-4024-07. eThe values for the laser and mirror systems assume a 30-year lifetime and CapaCitY factors of 0.75-0.9. fMirror I system parameters are defined by SOLARES “baseline system” and Mirror II system for low (1 ,100 km) orbit gThe SOLARES baseline system is designed to deliver 81O GW to 6 sites; 2 SOLARES basellne sites actually provide 270 GW.

the Northeast United States, Europe, and tion strategies or for which mitigation is Japan) and possible receiver siting in other na- too costly to make SPS competitive; and tions, with their particular environmental con- 2, they have a great bearing on the system straints, need to be explored. design, e.g., choice of frequency, power level and distribution may be determined The regional political problems may be by the results of bioeffect and atmos- more severe than the technical ones, especial- pheric studies and these may in turn con- ly in light of past controversies over the siting trol hardware design, cost, and land use. of powerplants, powerlines, and military radar and other facilities. While the construction If an SPS program is pursued, the assessment and operation of receivers might be welcomed of environmental risks should receive the by some communities on the basis of eco- highest research priority. Some studies such as nomic benefit, others might oppose nearby re- bioeffects research may require substantial ceiver siting for a number of reasons, in- time to complete; the resolution of environ- cluding: environmental, health and safety mental uncertainties could affect the develop- risks; fear that the receiver would be a target ment schedule of SPS. Much of the environ- for nuclear attack; fear of decreased land mental research needed in the assessment of values; preference for an alternate use of the SPS is applicable to other studies and would be land; objection to the receiver’s visibility; and valuable whether or not an SPS program is for rural Americans, resistance to the intrusion undertaken. Conversely, many of the en- of urban life. vironmental questions associated with SPS are also being addressed in other “generic” re- It is essential that many of the environmen- search programs such as those investigating tal uncertainties be diminished and that the microwave bioeffects and upper atmosphere effects are shown to be, at worst, comparable physics. The delineation of which environmen- to those of alternate inexhaustible energy tal risks are most important would, to a large sources, before commitment to the develop- extent, depend on the specific design concepts ment of SPS because: that showed the greatest promise. 1. environmental effects may be identified for which there are no acceptable mitiga- 48 • Solar Power Satellites

ELECTROMAGNETIC COMPATIBILITY

How would SPS affect other users of the munication. Some also use the spectrum for electromagnetic spectrum?* remote sensing. All would be affected in some way by SPS. Whether SPS were to be eventually deployed as a microwave, laser, or mirror system, Geosynchronous Satellites.– These would be it would affect some portion of the elec- most strongly affected by the microwave sys- tromagnetic spectrum. Other users of the spec- tems. They could be expected to experience trum would be concerned about the nature of microwave interference from noise at the fun- potential detrimental effects, whether they are damental SPS frequency (e.g., 2.45 Ghz for the amenable to amelioration and, if so, what the reference design), spurious emission in nearby costs would be. A microwave system would be bands, harmonics of the fundamental SPS fre- the most problematic because communica- quency, and from so-called intermodulation tions of all sorts share this general portion of products. All radio frequency transmitters gen- the spectrum. In addition, a wide range of erate such noise and receivers are designed to other electronic devices (e. g., sensors, com- filter out unwanted effects. However, the puters) are susceptible to microwave inter- magnitude of the power level at the central ference. frequency and in harmonic frequencies for a microwave SPS is so great that the possibility The Public of degrading the performance of satellite receivers and transmitters from these spurious Deploying SPS would markedly change the effects is high. visual appearance of the night sky. A set of reference system satellites equally spaced In addition to the direct effects from micro- along the Equator would appear as a set of wave power transmissions, geosynchronous bright stationary “stars” whose total effect for satellites could also experience “multipath in- observers on longitudes near the middle of the terference” from geostationary power satel- set and for all latitudes along these longitude lites due to their sheer size. In this effect, mi- lines would equal the Moon at about quarter crowave signals traveling in a straight line be- phase. Nonstationary satellites such as an LEO tween CEO communications satellites would deployed laser or mirror system would create experience interference from the same signal the effect of bright moving “stars.” The effect reflected from the surface of the power of such satelIites on the night sky has not been satelIite. calculated. However, it could be expected to The sum of all these effects would result in a equal the overall effect of the 60-satellite set limit on the distance that a geosynchronous of reference satelIites. satellite must have from the SPS in order to Some observers might well enjoy the sight of operate effectively. The minimum necessary manmade “stars” added to the night sky. spacing would depend directly on the physical Many, especially those in countries who failed design of the satellite, the wave length at to benefit from the generated power, might which it operated, and the type of transmission strongly resent the intrusion on the celestial device used (i.e., klystron, magnetron, solid- landscape. state device). Since a microwave SPS would have to share Space Communications the limited resource of the geostationary orbit with other satellites, the value of the minimum All artificial Earth satellites use some por- spacing has emerged as one of the most crit- tion of the electromagnetic spectrum for com- ical issues facing a geostationary SPS. How- ever, in the absence of a specific design, it is ‘See ch. 8 impossible to characterize the exact form and

Ch. 3—Issues and Findings ● 49 nature of the interference. Additional informa- At present the minimum spacing for domestic tion is essential to calculate the minimum re- geostationary satellites is 40 in the 4/6 GHz quired spacing. In addition, even if the design band and 30 in the 12/14 HGz band. At these parameters were known accurately, the theory spacings, a maximum of 90 4/6 GHz band satel- of phased arrays is insufficiently developed to- lites and 120 12/14 GHz band satellites could day to predict the minimum distance. Esti- theoretically coexist at geostationary alti- mates of the minimum necessary spacing tudes, in the absence of SPS. Current research range from 1/2 0 to 10. The lower limit would activity in the 20/30 GHz band is likely to lead probably be acceptable. However, a minimum to much greater capacity and smaller spacings spacing much greater than 10 would result in for that band by the time an SPS might be too few available geostationary slots to allow deployed. But even with these and other un- both types of users to share the orbit unless predictable advances in communications tech- many communications functions could be ac- nology in space and on the ground, competi- commodated on a few large space platforms. tion for geostationary orbit slots is likely to be high. At present, some 80 satellites share the geostationary orbit worldwide, and by 1990 The laser and mirror systems in low-Earth or- that number is expected to increase signifi- bit are unlikely to interfere with geosynchro- cantly (fig. 6). Even though improvements in nous satellites except in the relatively improb- technology will lead to a reduction in the total able event that one of the mirrors passes pre- number of satellites necessary to carry the cisely between the geosynchronous satellite same volume of communications services, and its ground station, and even that interrup- total service is expected to rise dramatically. tion would be for so short a time as to pose no serious problem.

Other Satellites. – In addition to geosynchro- Figure 6.—The Number of Geosynchronous nous satellites operating at the same altitude Satellites as a Function of Time as the CEO SPS, there are numerous military and civilian satellites in various low-Earth orbits that might pass through an SPS microwave beam. Such satellites could in principle protect themselves from adverse interference from the SPS beam by shutting down uplink communications for that period, and improving shielding for data and attitude sensors, computer modules, and control functions. Whether this action would be feasible depends on the particular mission the satelIite is to perform. For some remote sensing satellites, a shutdown could mean loss of significant data. It would not be feasible for the SPS to shut down for the few seconds of satellite passage. It might also be possible for many satellites to fIy orbits that will not intersect the SPS beam.

The laser and mirror systems might interfere 1980 1985 1970 1975 1980 1985 1990 with nongeosynchronous satellites by causing Year reflected sunlight to blind their optical sensors or by passing through communications beams. SOURCE: W. L. Morgan, Comsat Technical Review, 10 vol. 1,1980. Of the two systems, the mirror system would 50 ● Solar Power Satellites

cause the most problems because of the size Effect on Terrestrial Astronomy of the mirrors and their orbital speed. To date, and Aeronomy no one has calculated the possible adverse effects due to this cause. None of the proposed SPS systems benefit astronomical research except insofar as they Deep Space Communications. – Because would indirectly provide a transportation deep space probes generally travel in the plane system and construction capabilities for plac- of the solar system (known as the ecliptic), ing large astronomical facilities in space. The they would be especially affected by a geosta- detrimental effects would vary depending on tionary microwave SPS. A microwave SPS the system chosen. The impacts of a micro- would effectively prevent ground communica- wave system are likely to be severe for both tion with the probe when the latter happens to optical and radio astronomy. An infrared laser lie near the part of the ecliptic that crosses the system is likely to have fewer detrimental ef- Equator. This interference is especially serious fects on both forms of astronomy, and the mir- for deep space vehicles because it is essential ror system would have its most serious effect to be able to communicate with them at any on optical astronomy. time for the purposes of orbit control and for timely retrieval of stored data. Optical Astronomy.– Diffuse reflections from the reference system satellites would It would be possible to avoid such inter- cause each to be as bright as the brightest ference by establishing a communications phase of the planet Venus, and produce a dif- base for deep space probes in orbit. As we fuse halo of light around it. Because the penetrate deeper into space, this may be ad- satellites appear to remain stationary along visable for other reasons. If not, such a com- the celestial Equator, a system of 15 to 60 munications station would effectively add to satellites would meld together to block obser- the cost of the SPS. vation of very faint objects along and near the Equator for telescopes located on Earth be- Terrestrial Communications and tween the longitude limits of the satellites (fig. Electronic Systems 7). Some major non-U. S. telescopes would be affected as well. Telescopes in orbit, such as Both civilian and military terrestrial com- the U.S. Space Telescope scheduled to be munications, radar, sensors, and computer launched in 1984, will travel in nonequatorial components would suffer from a number of orbits and therefore would not be affected possible effects of a microwave beam. Direct significantly by a reference SPS except to interference can occur from the central fre- require increased pointing and control com- quency or the harmonics. In addition, scat- plexity on the Space Telescope. tered and reflected radiation at these frequencies from the rectenna, and rectenna emissions The effect of diffuse reflections from an could cause additional interference problems LEO-based laser SPS could be expected to be for terrestrial receivers. At the very least, much less of a problem for observations of ob- rectennas would have to be located far enough jects near the Equator because the laser por- from critical sites such as airports, nuclear tion of the satellite system would be constant- powerplants, and military bases to render ly in motion. Thus, no part of the sky would be potential interference as small as possible. In permanently blocked from view. The relay addition, equipment would have to be rede- satellites located in geostationary orbit would signed to permit far better rejection of un- subtend a very small angle as seen from the wanted signals than is now necessary. This ap- surface of the Earth. Though they would be pears to be feasible given enough time and visible as small points of light, they would be funds for the electronics industry to respond. considerably fainter than the geostationary

Ch. 3—Issues and Findings ● 51

Figure 7.—The SPS Brightness Profile moving patches of diffuse light that would completely disrupt the observation of faint objects that lie in the direction of the satellite paths. Thus, astronomers would need to remain outside a 30()-km diameter circle surrounding the site in order to avoid this problem. Radio Astronomy. – Radio astronomy would suffer two major adverse affects from microwave systems: 1 ) electromagnetic interference from the main SPS beam, from harmonics, from scattered or reflected SPS signals, and from reradiated energy from rectennas; and 2) additional sources of thermal noise radiation –40° –20° 0° 200 40“ 60“ 80“ in the sky that have the effect of lowering the Declination signal-to-noise ratio of the radio receivers. Studies by terrestrial radiotelescopes of faint Note: This figure shows the predicted brightness of the sky as a result of a 60-satellite SPS system along the meridian at local midnight for Kitt Peak radio objects near the Equator would be im- National Observatory at the vernal equinox. The calculation of this profile is based on an assumed 4 percent diffuse albedo possible. Neither the laser nor the mirror systems would contribute to the first effect; SOURCE: Workshop on SPS Effects on Optical and Radio Astronomy, DOE/Conf 7905143, P. A. Ekstron and G M Stokes (eds.). however, they would raise the effective temperature of the sky background. Low-level measurements such as scientists now routinely satellites of the reference system and would conduct to measure the amount of back- not interfere with optical observations. How- ever, large moving satellites would present op- ground radiation from the primordial explosion of the universe would thus be impossible tical astronomy with another observational from terrestrial bases. Thermal microwave obstacle. Scattered Iight from them would vary radiation from the satellites would exceed in intensity as the satellite passes near a present standards for radio interference at celestial object of interest, making calibration nearly all wavelengths. of the nearby background light very difficult. The laser satellite would interfere with infrared Space basing of radio telescopes, especially astronomy studies involving wavelengths near on the far side of the Moon, would eliminate the transmission wavelength of the beam. Pho- the impact of SPS and other terrestrial sources tometry and spectrometry experiments would of electromagnetic interference. However, be severely compromised during any brief or- such proposals, though attractive from the bital period when the relay satellite passed standpoint of potential interference, are within a few degrees of an observing tele- unlikely to be attractive to astronomers for scope. many decades because of their high cost and the relative inaccessibility of the equipment. The mirror system, which would involve a number of large, highly reflective moving mir- Optical Aeronomy. –Much of our knowledge rors in low Earth orbit, would have very serious of the upper atmosphere is gained by night- effects on optical astronomy. While the time observations of faint, diffuse light. Some precise effect has not been calculated, it of the observations that are made today must would render a large area (a circle of radius be carried out in the dark of the Moon. The 150 km) around the ground stations unaccept- presence of satellites equal in brightness to a able for telescopic viewing. Because of diffuse quarter Moon would effectively end some reflections from the atmospheric dust and studies of the faint airglow and aurora. Other aerosols that are up to 3 km above the ground observations would be severely limited in station, the individual mirrors would create scope. 52 . SoLar Power Satellites

SPACE PROGRAM

How would development of the SPS affect administration stated that: “it is neither feasi- our civilian space program?* ble nor necessary at this time to commit the United States to a high-challenge space engi- If pursued, an SPS program would be the neering initiative comparable to Apollo. ” In largest and most ambitious space program the absence of a long-term goal such as SPS, ever undertaken. SPS development could pro- some have predicted that future space efforts vide: 1 ) new capabilities for future space ven- wouId lag, or become overwhelmingly military tures; 2) spinoffs for civilian and military use, in nature. On the other hand, there is concern in space as well as other areas; 3) a political that an SPS commitment would draw re- and programmatic focus for the civilian space sources from or otherwise interfere with other program; and 4) potential furtherance of U.S. space activities, leading to an unbalanced ef- domestic and foreign policy goals. fort. In addition, for SPS as well as other less An SPS program would require the develop- expensive programs, the annual appropriations ment of a high-capacity space transportation procedure for NASA often results in budgetary system, the construction of large space struc- and programmatic uncertainty; development tures, and perhaps the deployment of manned of SPS would require long-term financial plan- space bases. I n addition, an extensive indus- ning and long-term commitment to the project. trial infrastructure would be needed to support In addition to its use as a source of electrical these activities. The hardware, knowledge, and power, the SPS should be judged by whether it facilities generated by such a program would is in accord with national interests as reflected significantly increase our overall space capa- in national space policy. The NASA Act of bilities and lay the groundwork for future in- 1958 (as amended), states that space activities dustrialization, mining and, perhaps, the col- should be for peaceful purposes, and can be onization of space. undertaken in cooperation with other coun- Direct technological spinoffs can be ex- tries, to further the “general welfare and pected in the development of improved large security” of the United States. In 1978 the space platforms, energy transmission devices, Carter administration, in its October “Fact ground illuminating systems, high-efficiency Sheet on U.S. Civil Space Policy,” reaffirmed solar celIs, and Iife-support systems. these goals while emphasizing the practical and commercial benefits of the civil space pro- Conversely, SPS development will benefit gram. A civilian-run SPS program open to inter- from prior developments in space technology, national participation would further current most notably in space transportation and space policy goals. systems for automated construction of space structures. Involvement by NASA in SPS operation might require a change of NASA’s current An important consideration is the extent to charter, which restricts the direct operation of which an SPS program wouId serve as the commercial ventures. Currently, DOE has focus and driving-force for the space program prime responsibility for solar energy research, as a whole. In the 1960’s, the U.S. civilian ef- while NASA is responsible for the U.S. civilian fort was centered on Apollo; in the 1970’s on space program. An SPS program would require the Space Shuttle. However, in 1978, the Carter extensive cooperation between the two agencies; if this caused difficulties, a separate agency or some other organizational alter- *For extended discussion see ch. 6 native might prove preferable. Chapter 4 POLICY OPTIONS Chapter 4 POLICY OPTIONS

Because the solar power satellite (SPS) is a decade. The Nation must also decide when to new energy concept, much of this assessment proceed with a research program and at what has Ied across previously uncharted territory. pace. SPS has potential for supplying a portion of Figure 8 represents a series of possible deci- U.S. electrical needs, but current knowledge sion points for SPS. If research on SPS finds no about SPS, whether technical, environmental, impediments to continued pursuit of SPS, the or sociopolitical is still too tentative or uncer- first in the series of development decisions tain to decide whether SPS would be a wise in- couId occur sometime between 1990 and 2000. vestment of the Nation’s resources. Further By that time, the factors that relate to energy research and study, based on the findings of demand and supply and space transportation this and other assessments, ’ 2 would be needed will be much clearer than they are today. The in order to formulate such a decision properly. United States will have had about 10 years of The kind and pace of a research program, if experience with the space shuttle and with ini- one is to be conducted, will be determined by tial testing of space platform components. perceptions of when development decisions Planning and perhaps testing will have begun need to be made. for a second-generation space transportation Decisions about SPS development involve system. The resuIts of the Nation’s long-term an important tradeoff. I n time, more can be energy conservation efforts will be felt and learned about the context within which SPS assessed, and electricity demand projections would operate. Furthermore, in view of this for 2000 and afterwards will be better defined study’s analysis of future U.S. electricity de- than currently possible. Further, a decision mand and the availability of alternate energy about the breeder may have been made and sources (see ch. 6), domestic need is not likely the potential of the fusion, energy storage, and to be high enough for SPS before 2015-25. terrestrial solar technologies may be more cer- Therefore, development and deployment deci- tain. sions do not have to be made before the The results of continued tracking of the in- 1990’s. However, action should be taken in a ternational, institutional, and public opinion timely manner. Since the development of a factors relevant to SPS will also contribute to major energy and space system may take more the decision. In particular, the international than 20 years, a decision about whether to community’s future energy needs and supply develop SPS will probably need to be made potential will be better known, as well as its before the end of the century. The develop- willingness to cooperate in a multinational ment of SPS may need to be started as early as development program. 1990, if high-growth projections for electricity seem plausible at the time. If an SPS develop- Finally, the results of research related to SPS ment program is eventually initiated, the Na- wilI be available and can be used to support or tion must also decide whether it wishes to pur- reject a decision whether to proceed with SPS sue SPS as a unilateral or as an international development. Some of the needed research is venture. The tasks before the United States in generic in nature, and will be done in other this decade are to determine how much and programs whether or not SPS is developed. what kinds of information are needed in order Among others, these include most of the Na- to make a sound decision sometime in the next tional Aeronautics and Space Administration’s (NASA) activities in space transportation, ‘Program Assessment Report Statement of Findings, SPS Con- space structures, photovoltaics, materials and cept Development and Evaluation Program, DO E/E R-0085, humans in space, as well as the Department of November 1980. ‘National Research Council Report of the Committee on Satel- Defense’s (DOD) and the Department of lite Power Systems, June 1981 Energy’s (DOE) laser programs. To some extent

56 ● Solar Power Satellites

Figure 8.—SPS Program Phases and Decision Points

Program level (funding)

Demonstration

Systems ...... engineering, space testing

Research, component testing

CDEP

No program DP 1 DP 2 DP 3 DP 4 Time

● DP 1 ● DP 2 ● DP 3 ● DP 4 — No program — No program — No program — No SPS — Research — Research — Research — Research . Initiate development — Continue systems — Systems engineering engineering — Demonstration — New demonstration — Deployment SOURCE: Office of Technology Assessment. they also include work done in the terrestrial eventually require a research program spe- photovoltaics (DOE) and microwave bioeffects cifically funded for SPS. (the Food and Drug Administration, the En- vironmental Protection Agency, etc.) pro- In order to make an informed decision about grams. However, many needs are directly the SPS, information about three different related to SPS technology and therefore will types of factors will be needed: Ch. 4—Policy Options ● 57

1. Contextual, independent factors. These Sometime in the next decade, the contextual are factors that are independent of SPS framework for the future of SPS may be known but which will markedly affect the need well enough to make an informed decision for SPS or the ability to conduct the proj- about the need for SPS. As time goes on, a nar- ect: rowing of future projections will occur and ● Future U.S. and global electricity de- knowledge of these factors will be integrated mand. If demand is relatively low, the into the overall decision about SPS. need for a new, capital-intensive energy system will be low as well. If future de- 2. Contextual, semi-independent factors. mand is very high, there could be a These are the factors that arise largely commensurate need for SPS. Conserva- from the public perceptions and interna- tion, increased end-use efficiencies, and tional and institutional framework of SPS. the expansion of dispersed electrical Though they are markedly diverse in con- generation could all affect overall de- tent, they have the unifying feature that mand for centralized electricity. they will each affect an SPS research pro- ● Cost, kind, and availability of alter- gram only slightly but an SPS develop- native electricity sources. If other po- ment program rather strongly. They will tential future electric energy sources need to be tracked, studied, and evalu- turn out to be more expensive than a ated as any SPS research program pro- projected SPS, then SPS may be desira- gresses. They also possess the character- ble even if electricity demand is rela- istic that there is no point at which one tively low. On the other hand, the devel- can say that enough is known about them. opment of other technologies might Rather, a development decision must take preclude the need for SPS. The status of them into account as factors that must be breeder and fusion technologies, the considered in Iight of what is known about cost of terrestrial solar and the ad- them at the time. visability of expanding the use of coal ● International interest and involvement will all affect the need for SPS. in SPS. The worldwide community will ● U.S. and global space capabilities. A be interested in SPS for its potential to rapidly expanding space program with provide energy. They will also be con- extensive experience and capabilities cerned about the effects it may have on would make an SPS program much the use of the geostationary orbit, mili- more feasible than would a low-level tary and national prestige implications, program. The experience with the shut- how it may affect communications, and tle and other space vehicles will shed how it may affect the appearance and light on space transportation capabili- use of the night sky. They may also be ties and costs. interested in joining with the United Although an SPS research program is not States in multinational development of likely to be affected by these factors, they will SPS. Hence, it will also be important to have a great effect on an SPS development explore possible modes and means of decision. Each of the factors needs to be international cooperation. tracked, studied, and continually reevaluated ● Institutional framework. A main con- for its impact on an SPS decision. Projections cern of any SPS program would be to of these factors 10 to 20 years in the future will continue to study the institutional have to be made as well, and amended as more structures that now exist in the utilities information becomes available. Because these industry, the financial community, and factors are of universal interest, such studies Government, and to identify the major need not be funded by a specific SPS program; factors that could influence the course they will be investigated by other energy and of SPS development and affect its space programs. feasibility.

83-316 0 - 81 - 5 58 ● Solar Power Satellites

● Public opinion issues Public percep- — space charge effects, and tions and public involvement are im- – photovoltaic design and testing. portant components of any publicly ● Space construction and space transpor- funded program. Dissemination of in- tation: formation and sharing of research — evaluate best transportation scheme results would be essential to the SPS for demonstration and program, even in the research phase. It — evaluate best construction scheme. would also be important to continue to information from all three sorts of factors solicit responses from segments of the will set the framework and determine the ap- public that would be especially af- propriate time for development decisions. It is fected, either positively or negatively, important to emphasize that a decision not to by SPS development. develop SPS depends on the same information 3.Technical factors specific to SPS. Knowl- as a decision to proceed with SPS. If further edge about these factors can be gathered research finds no major technological impedi- or generated by deliberate effort. Answers ment to proceeding with SPS and the combina- to specific questions in this group will tion of supply alternatives and demand needs have an immediate effect on SPS develop- indicate that it would be prudent to proceed ment decisions. The kind, quantity, and with the next stage, the program could enter quality of the information as well as the the engineering verification phase where var- time at which it can be available are part- ious systems are tested and a demonstration ly dependent on the level of funding. Four system chosen. This would set the stage for the general categories of this sort of informa- next decision point. tion are evident: ● Environment and human health: [f it were possible to make a decision to pro- — microwave and laser bioeffects, ceed with the project early in the process (i. e., –high energy particle and ionizing ra- during the research phase) the various phases diation effects on humans in space, could overlap considerably. For instance, the — ionospheric effects due to micro- early stages of demonstration could begin wave transmission, before the engineering verification phase is – land-use impacts, entirely complete. Some economic benefits —offshore rectenna environmental ef- might accrue from such a procedure. However, fects, because of the very high front-end costs for – launch vehicle exhaust effects on at- SPS, any proposal to proceed with develop- mosphere, and ment will need to be scrutinized very carefully —weather modification from mirror to be sure it is cost effective. That will systems. necessitate more time and study in the veri- ● General system studies: fication stage than might be true for a less —alternate systems (identify which costly technology, making it less likely that the areas need further research, and pos- various phases will overlap. sible testing of components), — component and system costs, and SPS research could proceed at different —comparison of alternate systems. rates and along different lines, depending on ● Component testing and evacuation: the level of funding that is made available. The –Klystrons/magnetrons/solid-state de- following presents two different policy op- vices, tions. One is characterized by zero funding for – high-powered, continuous-wave la- specific SPS research; the other by a sliding sers (EDL, solar pumped, FE L), scale of funding. They do not exclude one — SIip ring designs, another, i.e., pursuing one option today would –deployable, large-area, lightweight not necessariIy exclude changing to a different space structures, option as time proceeds and information Ch. 4—Policy Options ● 59

grows. For example, it could be considered sary. in addition, appropriating no specific prudent to begin with no specific funding for funding for SPS carries with it the risk of SPS and proceed to allocate a few million discouraging future international cooperation, dollars per year after a few years. Conversely, or of allowing other countries to take the lead a vigorous funding pace may produce results in SPS development. A final problem with op- quickly enough so that from the standpoint of tion A is that the agency designated to track those factors that are amenable to research, a SPS may find it very difficult to allocate its development decision could be made before financial resources for SPS without some spe- 1990. But because the independent factors are cific allocation in its budget (even though unlikely to be known well enough before 199o, small). research funding might then be reduced to a What could be learned from such an option? lower level to keep the program going pending Other Federal and non-Federal programs are a decision based on the independent factors. currently exploring issues that are related to Option A: SPS development. By tracking this generic re- No specific funding for an SPS program. search, information of great value to the development decision could be gathered and Although it would be nearly impossible to analyzed. pursue an SPS program without specifically allocating funding for it, this option would not ● Microwave bioeffects.The proliferation of necessarily mean terminating all interest in microwave devices at various frequencies SPS. A zero level option could be followed by makes research into this important area designating an agency (e.g., NASA or DOE) to mandatory whether there is an SPS program track generic research that is applicable to or not. FDA, EPA, and DOD are studying SPS, as well as monitoring and coordinating in- microwave bioeffects. ternational interest in SPS. One possibility is to ● Photovoltaics DOE maintains a strong ter- set up a high-level advisory committee to serve restrial photovoltaics program. Together this latter function. As in the other option, with private industry and university projects, periodic reevaluation of the potential of SPS this program is studying some aspects of would also be needed, in this case to decide photovoltaics that are of great interest to whether specific funding should be instituted SPS. However, because terrestrial photovol- or the program terminated altogether. taic systems have vastly different needs and constraints than space photovoltaic sys- The rationale behind option A is to keep SPS tems, additional research would probably be alive as part of our arsenal of possible energy needed for SPS. supply options without making a serious com- ● Space-related activities. NASA, DOD, and mitment at this time. It has the advantages the European Space Agency (ESA) are pursu- that the risk of premature funding is greatly ing programs in space transportation, space reduced, as well as the upfront costs. The structures, humans in space, and space pho- longer the country can wait before funding a tovoltaics by designing and building the program directed towards SPS research, the shuttle, advanced expendable launch vehi- more likely it is that other programs will have cles, space lab, a 25 kW space power supply, generated helpful data for SPS. etc. On the other hand, there is little margin for ● Laser programs. High-powered, continuous- error in such an approach. If, under option A, wave lasers are currently in an early stage of inadequate information is generated, the SPS development. Some of the research on high option might be neglected or foreclosed at a energy pulsed lasers being pursued by the time of future decision; or, if the independent DOD for weapons applications and by DOE factors indicate a strong need for SPS, then an for fusion studies will be relevant to the SPS expensive crash program of research to resolve laser concept. Universities and other re- the questions specific to SPS may be neces- search labs are studying high-powered, con- 60 • Solar Power Satellites

tinuous-wave lasers. This research would be since they are the most important in determin- directly applicable to a laser SPS. ing the feasibility of SPS. However, they could ● Alternateve energy sources. The resuIts of also take the longest to resolve. Some compo- R&D, prototype construction, and operation nent testing and studies of alternative systems of other electricity sources, including solar could receive high priority. The amount of thermal, breeders, ocean thermal energy funding which would be made available would conversion, and fusion, will be of great im- depend on an evaluation of previous research portance in determining future need for SPS. findings and the state of projected supply and demand for electricity in the 21st century. However, many issues directly pertinent to SPS cannot be answered by generic research It may be prudent to start at a low level of programs. For instance, while microwave bio- funding and later accelerate research that is effects experiments are being performed in specific to SPS as well as make greater funding generic research programs, the number of available for SPS related generic studies. studies on low-level, long-term exposure to SPS Another possibility is to actively solicit fund- frequency microwaves is small. To gain infor- ing for projects of joint international-U. S. in- mation directly relevant to SPS, some specific terest, perhaps by offering to match foreign SPS funding will be needed. funding for research projects undertaken outside the United States, but which are of in- Option B: terest to U.S. planners. An accelerated re- Funding of $5 million to $30 million per search program ($30 million per year) could in- year. clude some component testing in space as welI This option is designed to gather the neces- as at the Earth’s surface. It could also include sary information before a development deci- at least one shuttle mission (post 1985) and sion is needed. It minimizes the risks of not some space-related experiments on other shut- gaining the sufficient and timely information tle flights. It would seek to answer the major necessary for a rational decision. environmental and health and safety questions before 1990 and also conduct extensive sys- This program would, like option A, make as tems studies. If these concerns are seen to pose much use as possible of generic research. It no impediments, accelerated funding would would extend the generic research into areas provide the quickest way of entering a devel- specific to SPS by making small amounts of opment phase. funding available for expanding generic programs essential to the SPS development deci- Making funds available for SPS-specific re- sion. It would also initiate research that is not search should ensure that enough information being done in generic programs and explore is eventually available in order to make a ra- ways in which to pursue some of this research tional development decision. This approach jointly with other nations. In addition, it would also has the advantage that it could provide track and study the various semi-independent for extensive international cooperation early factors (international, institutional, and public in the research phase before seeking more ex- opinion) which would also have a profound ef- tensive financial and managerial cooperation fect on SPS decisions. It would actively seek in any subsequent development or construc- and encourage international cooperation in tion phase. This would spread the decision to SPS research. proceed or drop SPS development to other countries as well. Table 5 summarizes the most important research and study needs and gives a very rough However, a higher level of spending ($30 estimate of what it would cost to do each item. million or so per year), here and abroad, would The starred items are ones that could be pur- make it more likely that an entrenched SPS sued in the context of a few million dollars of constituency would form, giving the program funding per year. The most critical issues re- momentum and making it harder to stop; more late to the environmental and health area, information may not make a program easier to Ch. 4—Policy Options ● 61

terminate. Under such conditions, our under- transmitting power will develop too early and standing of SPS technology may outstrip our close out SPS options which are uncertain in knowledge of future electricity demand. It is the near term but which may have more long- also possible that support for a given mode of run potential.

Table 5.—Summary of Research and Study Needs

Expansion of generic research Estimated Estimated Research/study area to SPS-specific needs cost — SPS-dedicated projects costs Environmental and human health ● Microwave bioeffects $5 million to Quantify SPS risks. $2 million $10 million Epidemiological microwave studies. ● Laboratory studies of long-term exposure to low-level microwaves at 2.45 GHz. Determine possible nonthermal effects, and dose-response relationships, establish extrapolation laws. ● Ionospheric studies ● Study of ionospheric scaling — ‘Ionospheric equivalent $10 million laws. heating. Upgrade Arecibo facility. Study SPS equivalent heating in upper atmosphere. Test scaling laws and effects on representative telecommunication systems. ● Atmospheric studies ● Track and augment observa- $2 million ● Experiments to test $1 million tions of the atmospheric effects of SPS effects of launch effluents effluents on mag- from the shuttle, other ex- netosphere and to pendable launch vehicles and increase understanding of high altitude rockets. that region. Quantify and study SPS effects on the hydrogen cycle, and formation of noctilucent clouds. Refine and test ground $0.3 million to ● Study effect on local cloud models. Study $5 million climate of SOLARES-type meteorological and air system using an array of quality impacts. ground heaters or a solar pond. Determine the nature and $0.5 million *Studies of possible effect of ionospheric de- weather modification, pletion, especially in beam scattering lower ionosphere. Utilize and spreading. other rocket launches and Identify transportation observe the effects on scenarios that representative telecom- minimize impacts. munication systems. ● Ionizing radiation ● Track and augment existing $2 million to studies of effects of ionizing $3 million radiation on humans. Study shielding methods. ● Space ● Track and augment existing $0.2 million programs examining the risks and protection measures for humans in space. ● Electromagnetic ● Study potential electromag- $2 million ● Investigate antenna $1 million interference netic interference and design patterns of klystron, mitigating techniques. Improve magnetron, solid- theory of phased array. state devices (see below), their noise levels, and out-of-band harmonics. 62 ● Solar Power Satellites

Table 5.—Summary of Research and Study Needs—Continued

Expansion of generic research Estimated Estimated Research/study area to SPS-specific needs cost SPS-dedicated projects costs • Environmental Offshore receiver studies $0.5 million impacts of Land use studies $2 million receiver siting General system studies ● Laser system ● Develop a “reference” $0.5 million to laser system $1 million ● Mirror system *Develop a “reference” $0.5 million to mirror system $1 million ● Alternative microwave *Develop alternative microwave systems *Perform a true compar- $1 million ative study between SPS alternatives using common technology and cost basis. Component testing and evaluation ● Microwave ● Continue solid-state device $3 million to Develop solid-state $2 million to transmission improvement, study noise, $6 million phased array $10 million interference problems Study alternative micro- $.3 million to ● Test intermediate power $2 million wave devices, such as $1 million magnetron, high-power klystron photoklystron ● Solar thermal $1 million conversion . Photovoltaics ● Extend research to low mass, $2 million ● Adapt optimum $2 million thin film cells for space photovoltaics for SPS, i.e., low mass, high efficiency, radiation resistant ● Lasers ● Improve efficiency of EDL $3million to ● Build solar pumped $1 million to lasers, develop cooling mech- $10 million lasers $3 million anisms for space lasers ● Laser optics $0.1 million to (feasibility studies) $0.3 million . Mechanical ● Study means of $0.3 million components constructing slip ring and rotating joint *SOLARES mirror materials structures ● Mirror Develop prototype mirror $0.5 million design for shuttle launch of a single SOLARES mirror

‘Research priority. SOURCE: Office of Technology Assessment. Chapter 5 ALTERNATIVE SYSTEMS FOR SPS Contents

Page Microwave Transmission ...... 65 LIST OF FIGURES The Reference System...... 65 Figure No. Page Laser Transmission...... 78 9 Solar Power Satellite Reference Laser Generators ...... 79 System...... 66 Laser Transmission ...... 81 10 Satellite Power System Efficiency Laser-Power Conversion at Earth ...... 82 Chain ...... 67 The Laser-Based System ...... 82 11 Major Reference System Program Elements...... 68 Mirror Reflection ...... 86 12 The Retrodirective Concept ...... 69 The Mirror System...... 88 13 Power Density at Rectenna as a Space Transportation and Construction Function of Distance From the Alternatives ...... 89 Beam Centerline ...... 70 Transportation ...... , . . . . 89 14 Peak Power Density Levels as a Space Construction...... 91 Function of Range From Rectenna . . . . 70 15 SPS Space Transportation Scenario . . . 73 SPA Costs ...... 92 16 The Solid-State Variant of the Reference Reference System Costs ...... 92 System...... 78 Alternative Systems ...... 96 17 lndirect Optically Pumped CO/CO2 The Solid-StateSystem ...... 96 Mixing Laser ...... 80 The Laser System ...... 96 18 The CATALAC Free Electron Laser The Mirror System...... 97 Concepts...... 81 19 Optics and Beam Characteristics of Two Types of Laser Power Trans- LIST OF TABLES mission System (LTPS) Concepts...... 82 Table No. Page 20. The Laser Concept...... , ...... 84 6. Projections for Laser Energy Converters 21 Components of the Laser Concept . . . . 84 in 1981-90 ...... 83 22. The Mirror Concept (SOLARES) ...... 87 7. 500 MWe Space Laser Power System. . . 85 23. Reference System Costs ...... 92 8. Laser Power Station Specification. . . . . 85 24 How Cost Could Be Allowed...... 93 9. SOLARES Baseline Systerm ...... 88 25 Elements and Costs, in 1977 Dollars, for 10. Research— $370 Million ...... 93 the Baseline SOLARES System ...... 97 11. Engineering– $8 Billion ...... 93 26 Sensitivity of the SOLARES Mirror 12. Demonstration– $23 Billion ...... 93 System to Variations in System 13. SPS lnvestment– $57.9 Billion ...... 94 Parameters ...... 98 Chapter 5 ALTERNATIVE SYSTEMS FOR SPS

A variety of systems have been proposed for tutional, and public acceptance issues in the collecting, transmitting, and converting solar chapters that follow. power from space. Each system has its advantages and disadvantages, its benefits and draw- In order to estimate reliably and fully the backs. Each alternative system would use one range of costs and potential technical uncer- of three transmission modes — microwave, tainties for a given solar power satellite (SPS) laser, or optical reflector–to transmit power option, it would be necessary to subject it to to Earth where it is collected and converted to the same detailed analysis that the reference electricity or some other highly useful form of system has undergone during the last 5 years. energy. Each system would use numerous sub- Unfortunately, this analysis has not been ac- systems to collect and convert energy in space complished for the alternative systems. Hence, or on the ground. This chapter wiII character- detailed comparisons between systems will not ize the alternative systems and subsystems and be possible. At this stage it is possible only to discuss their potential for generating power compare the major features of each technol- from space. It will also describe four repre- ogy and note the uncertainties that should be sentative systems that serve as the technical addressed as conceptual development of the basis for discussion of the environmental, insti- various alternatives continues.

MICROWAVE TRANSMISSION

Because the atmosphere is highly transpar- and Space Administration (DOE/NASA) as a ent to microwaves, they constitute an obvious basis for study. It consists of a large planar candidate for the SPS transmission mode. In array of photovoltaic celIs located in the geo- addition, microwave technology also is well- synchronous orbit 35,800 km above the Earth’s known and is used today in a number of space Equator (fig. 9). The cells convert solar energy and terrestrial communications and radar ap- into direct-current (de) electricity that is plications. Microwave power transmission was conducted at high voltage to a phased-array first demonstrated experimentally in 1964, ’ microwave transmitting antenna mounted at and tested in 1974.2 3 one end of the photovoltaic array. Klystron amplifiers convert the dc electricity to high- The Reference System4 56 voltage radio-frequency power that is then radiated to Earth by slotted waveguides. A The reference system was selected by the receiving antenna (rectenna) on the ground Department of Energy/National Aeronautics reconverts the electromagnetic radiation into electric current and rectifies it into dc. After 1). F Degenford, M D. Sirkis, and PV H Steir, “Ttle Reflecting Beam Waveguide, ” I E EE Transactions 01 Microwave Theory being converted to high-voltage, low alter- Technology MIT-72, July 1964, pp 445-453 nating current (ac), the power can then be ‘Richard M Dickinson, “Evaluation of a Microwave High- either delivered directly to the conventional ac Power Reception-Conversion Array for Wireless Power Transmis- sion, ” Jet Propulsion Laboratory Technical Memorandum No grid or converted back to dc at high voltage 33-741, Sept 1, 1975 and delivered to a dc transmission network. ~R i chard M Dick InsOn, “Microwave Power Transmitting Phased Array Antenna Research Project Summary Report, ” Jet The amount of power delivered to the grid Propulsion Laboratory publication No 78-28, Dec 15, 1978 by each reference system rectenna has been ‘Department of Energy, “Satellite Power System Concept De- velopment and Evaluation Program Reference System Report, ” report No. DOE/E R-0023, October 1978 bR O Piiand, “SPS Cost Methodology and Sensitivities, ” The ‘C. C. Kraft, “The Solar Power Satellite Concept, ” NASA pub- F/na/ Proceedings of the Solar Power Satellite Program Review, lication No JSC-14898, July 1979 DOE/NASA Conf-800491, July 1980.

66 ● Solar Power Satellites

Figure 9.—Solar Power Satellite Reference System

Solar power satellite reference system

Solar cell arr

Transmitt

SOURCE: C. C. Kraft, “The Solar Power Satellite Concept,” NASA publication No. JSC-14898, July 1979

set at 5 gigawatts (GW)—or 5,000 megawatts The system is designed to deliver baseload, (MW). The microwave transmission frequency i.e., continuous 24-hour power to the electric was chosen to be 2.45 gigahertz (GHz). Max- grid. However, some variations in delivered imum microwave power density at the center power would occur. A seasonal fluctuation in of the rectenna (on Earth) was set at 23 output due to the variation of the Sun’s dis- milliwatts per square centimeter (mW/cm2), tance from Earth would cause variations in and the maximum power density at the edge of both incident insolation and photovoltaic cell the rectenna was set at 1 mW/cm2 (one-tenth temperature, the latter producing a conse- the current U.S. recommended occupational quent change in efficiency. In addition, around limit). The reference design assumes that all the spring and fall equinoxes the Earth’s materials would be obtained from Earth, and shadow would occult the SPS, resulting in a that the system lifetime would be 30 years with short period each night for about 6 weeks at no residual salvage value. local midnight (about 75 minutes maximum, at the equinoxes) where no solar radiation im- The area of the satellite’s photovoltaic array pinges on the satellite and therefore no power would be approximately 55 square kilometers 2 could be delivered to the grid (see ch. 9 for a (km ); the diameter of the transmitting antenna discussion of this effect). 1 km. The total in-orbit mass of the complete system, including a 25-percent contingency factor, would be either 51,000 or 34,000 metric Subsystem Description tons (tonnes), depending on whether silicon or ENERGY COLLECTION AND CONVERSION gallium arsenide photovoltaic cells would be Two photovoltaic concepts were considered used. for the DOE/NASA reference system. One uses

Ch. 5—Alternative Systems for SPS . 67

Figure 10.-Satellite Power System Efficiency Chain

57.81 GW 11.58 GW 10.50 GW 9.46 GW

Ga 63.18 GW 71.77 GW (Solar)

10.79 GW 10.29 GW 9.79 GW 70.81 GW Si Si 62.34 GW

Ga 9.08 GW 8.50 GW 8.50 GW 8.18 GW 6.96 GW 6.72 GW

9.08 GW 6.58 GW 5.79 GW 5.15 GW

overall efficiency = 6.970/. Ga MPTS efficiency = 63.00/. 7.06% Si

Abbreviation: “Ga” indicates the gallium-alum aluminum-arsenide option, “Si” the silicon option.

SOURCE: Department of Energy, “Satellite Power System Concept Development and Evaluation Program: Reference System Report,” DOE report No. DOE/ER-0023, October 1978. single crystal silicon converters that would cells: low mass per unit area, resistance to ther- receive sunlight directly; the other uses mal and radiation degradation, and higher effi- gallium-arsenide (GaAs) photovoltaic cells il- ciency. They have the disadvantages of rela- luminated directly and by mirrors in a 2:1 con- tively high cost, the limited production availa- centration ratio. bility of gallium, and a smaller technology base than for silicon cells. Because of these Silicon cells, currently used in all solar latter characteristics, these cells would be powered spacecraft, have the advantages of used in a 2:1 concentration ratio in the refer- an extensive manufacturing base, abundant re- ence system, trading the relatively expensive source materials, and lower cost per cell, as cells for less expensive Iightweight reflectors well as an R&D program in DOE aimed at ma- to concentrate sunlight on the cells. jor cost reduction for terrestrial cells. How- ever, silicon cells in space suffer degradation The structure that supports the solar cells from radiation effects and from high-operating would be an open-truss framework made of temperatures, and hence would probably re- graphite-fiber reinforced thermoplastic com- quire periodic annealing of the array surface posite (fig. 9). Because the solar array must be (possibly by laser or electron beam techniques) oriented toward the Sun and the transmitting or the development of silicon cells less af- antenna toward the Earth, a massive rotary fected by ionizing radiation. joint is essential in order to provide the nec- Gallium-aluminum arsenide photovoltaic essary mechanical coupling. Sliprings about cells have several advantages over silicon 400 m in diameter would be used in conjunc-

68 ● Solar Power Satellites

Figure 11 .—Major Reference System Program Elements

GEO

COTV

construction depot

Space freighter

SOURCE: R. O. Piland, Cost Methodology and Sensitivities,” The Final Proceedings of the Solar Power Satellite Program Review, DOE/NASA 1980. tion with the rotary joint in order to transfer reference system, these design considerations electric power from the array to the antenna. resulted in a l-km diameter antenna. It would be constructed of 7,220 subarrays each con- POWER TRANSMISSION AND DELlVERY taining from four to thirty-six 70-kW klystron The power transmission and delivery system power amplifiers connected to slotted wave- for the reference system design is common to guides for transmitting power to Earth. KIys- both photovoltaic options. It is composed of trons were chosen because their technology three major elements: the transmitting anten- and operating characteristics at low power na, the rectenna, and the substation. levels are well-known. However, they require a cooling system (probably heat pipes). Klystrons The selection of the microwave transmission of 70-kW continuous power rating have not frequency was based on tradeoffs between at- been built and tested at this frequency, so their mospheric attenuation and interactions with characteristics are not known in detail. the ionosphere as well as the sizes of the antenna and rectenna. The optimal frequen- Each of the more than 100,000 klystrons in cies were found to be between 1.5 and 4 GHz. the antenna must be properly adjusted or The reference frequency was selected to be “phased” to provide a uniform power beam 2.45 GHz, which lies in the center of the inter- and to point it. This adjustment is especially national Industrial, Scientific, and Medical critical at the very high, gross power level of (ISM) band of 2.4 to 2.5 GHz. the SPS beam. Were the antenna a totally rigid The size of the antenna is determined by the array of amplifiers precisely fixed in space, the transmission frequency, the amount of heat it adjustment could be accomplished once and is feasible to dissipate at the antenna, the for all just after the antenna is fabricated in theoretical limits of ionospheric heating, and space. However, because it would be desirable the maximum power densities chosen at for the antenna to be relatively flexible it ground level, i.e., at the rectenna.7 For the would be necessary to use an active system of phase control, a so-called “adaptive electronic ‘Raytheon Corp., “Microwave Power Transmission System Studies,” report No, ER75-4368, contract No NAS3-I 7835, De- control” in which a pilot beam, installed in the cember 1975. center of the rectenna and pointed toward the

Ch. 5—Alternative Systems for SPS ● 69

satellite, establishes a phase reference or beam to very low power (0.003 mW/cm2). The standard clock against which the individual transmission system would therefore require klystrons compare and adjust their phases (fig. continual ground-based guidance to keep it 12).8 operating as a coherent beam. By incorporating relatively well-known anti jamming An important safety feature inherent in this techniques in the pilot-beam generator, de- system is that loss of the pilot beam from the liberate or accidental diversion or misuse of rectenna would eliminate all pointing and the SPS beam could be prevented. phase control. Without the pilot beam, the klystron subarrays would immediately lose The parameters of the microwave beam are synchronization with one another and al I focus of critical importance in assessing the en- would be lost, resulting in the spreading of the vironmental impacts of the SPS. The peak power density at the transmitting antenna is ‘William C Brown, “Solar Power Satellites Microwaves Deliv- calculated to be 21 kW/m2. By the time the er the Power, ” Spectrum, June 1979, pp 36-42. beam reached the upper atmosphere it would have spread considerably and the intensity reduced to 23 mW/cm2, a power Iimit that was Figure 12.—The Retrodirective Concept set because theoretical studies suggested that at higher power densities, nonlinear instabilities could appear in the F layer of the ionosphere (200 to 300 km) as a result of the interactions between the beam and the electrically charged particles in this region. Recent experimental studies indicate that the limit in the lower ionosphere might be able to be set much higher, ’ thereby making it possible to decrease the size of the antenna and/or rectenna signifi- cantIy. With these design constraints, a theoretical beam power distribution was conceived resulting in the radiation pattern at the rectenna shown in figure 13, on which are noted the present U.S. recommendations for public exposure (10 mW/cm2) and the current U.S.S.R. occupational guideline (0.01 mW/cm2). The off-center peaks in figure 13 are called In the retrodirective-array concept, a pilot beam from the “sidelobes;” the level of intensity shown is a center of the rectenna establishes a phase front at the consequence of the 1-km antenna aperture transmitting antenna. Central logic elements in each of the (which is optimized to minimize orbital mass) antenna’s 7,220 subarrays compare the pilot beam’s phase front with an internal reference, or clock phase. The phase and the projected cumulative antenna errors. difference is conjugated and used as a reference to control The first sidelobe would have a peak intensity the phase of the outgoing signal. This concept enables the of 0.08 mW/cm2, less than one-hundredth the transmitted beam to be centered precisely on the rectenna and to have a high degree of phase uniformity. If this phase- current U.S. occupational exposure recom- control system fails, the beam would automatically be mendation, about 8 km from the beam center- defocused, dropping the power density to 0.003 mW/cm2, line; the intensity at the edge of the reference an intensity acceptable by current standards. This feature system rectenna (5 km from the beam center- has been referred to as the “fail-safe” aspect of the 2 microwave transmission system. line) would be 1 mW/cm –one-tenth the U.S. occupational exposure guideline.

SOURCE: William C. Brown, “Solar Power Satellites: Microwaves Deliver the ‘w Cordon, and L M Duncan, Impacts on the Upper Power,” Spectrum, June 1979, pp. 36-42. Atmosphere,” Astronautics and Aeronautics, July/August 1980

70 ● Solar Power Satellites

Figure 14.—Peak Power Density Levels as a Function of Range From Rectenna

USA standard 10

1.0

0.01 o 2,000 4,000 6,000 8,000 Radius from boresight (km) 0.005 I I I III 1 I I1 I I o1,000 2,000 3,000 4,000 5,000 Radius from boresight (miles)

0.001 Grating lobe spikes occur every 245 km for the 18-m sub- 0 5,000 10,000 15,000 20,000 arrays used on simulations although only two grating lobes are shown. The SPS 10-m subarrays have grating lobes Ground radius, m every 440 km.

SOURCE: Department of Energy, “Satellite Power System Concept Develop- SOURCE: Department of Energy, “Satellite Power System Concept Develop- ment and Evaluation Program: Reference System Report,” DOE ment and Evaluation Program: Reference System Report,” DOE report No. DOE/ER-0023, October 1978. report No. DOE/ER-0023, October 1978.

In addition to the relatively strong sidelobes, The rectenna design is quite insensitive both the finite size of the antenna subarrays and to the angular incidence of the microwave their projected misalinements would produce beam (within 100, and to variations in phase or much weaker “grating lobes, ” which for the amplitude caused by the atmosphere. Hence, reference system would occur at 440-km inter- rectennas would be interchangeable; the same vals from the rectenna. The integrated intensi- satellite could power different rectennas, as ty of these grating lobes, even for hundreds of long as they were equipped with the appropri- operational SPSs, would be well below even ate pilot beam needed for phase control of the the U.S.S.R. public-exposure guideline, as transmitting antenna. The reference rectenna shown in figure 14. would be composed of billions of dipole an- Ch. 5—Alternative Systems for SPS Ž 71

tennas placed above a transparent wire grid. sideration of the transportation options. The The microwave energy received by each dipole basis for all projected Earth-to-low-orbit would pass through a rectifier circuit that transportation concepts is the current U.S. would convert it to dc power at high current space shuttle, scheduled to become the opera- and low voltage. Several more conversions tional mainstay of the U.S. (and much of the would be necessary to condition the power for world’s) space program. the grid. The received power would first be Of the many possible shuttle derivatives and converted to ac and then transformed to high- other new transportation prospects, 12 NASA voltage low-current 60-cycle ac power and selected four different types of vehicles to sup- then either fed into ac transmission lines for ply the four basic transportation functions: delivery to the users or reconverted to high- voltage dc for transmission, a relatively new ● carrying cargo between Earth and low- transmission technology. Earth orbit (LEO), ● carrying personnel between Earth and Estimates of overall rectenna conversion ef- LEO, ficiency run from about 80 to 92 percent, and ● transferring cargo between LEO and the the extreme simplicity and repetitive-element geosynchronous orbit (CEO), and construction of the electrical components ● transferring personnel between LEO and would facilitate mass production at extremely CEO. low unit cost. Reliability of the rectenna should be extremely high, because each com- The designs of these four vehicles, called re- ponent would be ultrareliable and could oper- spectively, the heavy-lift launch vehicle ate redundantly. Hence replacement would be (HLLV), the personnel launch vehicle (PLV), the necessary only after a large number of individ- cargo orbital transfer vehicle (COTV), and the ual failures. personnel orbital transfer vehicle (POTV), are based on existing technology, although all None of the substation equipment involves would require considerable development be- technological advances beyond those that are fore reaching operational status. 13 14 15 16 projected through normal development by the electric utility industry. The major concern Both the HLLV and the PLV would utilize that has been expressed is the large scale of fully reusable flyback boosters similar to those the minimum individual power unit. Current originally considered by NASA in early shuttle grid control systems are quite adequate to han- designs in the late 1960’s. Both boosters would dle near-instantaneous switching of single employ methane-oxygen rocket engines for power units as high as 1,300 MW. Single unit (vertical) takeoff and airbreathing (turbofan) variations of 5,000 MW could present major engines for flyback to base for horizontal land- control difficulties to the utilities as they cur- ings. The HLLV orbiter would use oxygen- rently operate10 11 (see ch. 9 for a detailed description of utilities interface problems). “Robert Salkeld, Donald W Patterson, and Jerry Grey (eds ), ‘Space Transportation Systems, 1980-2000, ” VOI 2, AlAA Aero- ipace Assessment Series, A IAA, New York, 1978 SPACE CONSTRUCTION ‘‘G Woodcock, “Solar Power Satellite System Definition The mass and physical size of the space seg- Study, ” Boeing Aerospace Co., Johnson Space Center contract No NAS9-I 5196, pt 1, report No D180-20689, June 1977; pt 11, ment needed for an operational 5-GW satellite report No D180-22876, December 1977, pt I I 1, report No power station are larger by several orders of D180-24071, March 1978 magnitude than any space system heretofore “C Hanley, “Satellite Power System (SPS) Concept Defini- tion, ” Rockwell International Corp., Marshall Space Flight Cen- launched and therefore require careful con- ter, contract No NAS8-32475, report No SD78-AP-0023, April 1 ’378 ‘“J. G. Bohn, J. W. Patmore, and H W Faininger, “Satellite 15 Gordon R Woodcock, “Future Space Transportation Sys- Power Systems: Utility Impact Study,” EPRI AP-1 548 TPS 79-752, tems Analysis Study, ” Johnson Space Center contract No. September 1980. NAS9-I 4323, Boeing Aerospace Co. report No DI 80-20242-1 11 p j, Donalek, and J. L. WhYsong, “Utility Interface Require- (three volumes), Dec. 31,1976 ments for a Solar Power System, ” Harza Engineering Co , “Donald P, Hearth (Study Director), “A Forecast of Space DO E/E R-0032, September 1978 Technology 1980-2000,” NASA SP-387, January 1976. 72 . Solar Power Satellites

hydrogen rockets essentially identical to those area would serve as the transfer point for all of the current space shuttle, and then glide materials and personnel both up to CEO and back to base much like the shuttle does. Un- back down to Earth. Alternative strategies like the shuttle, it would be fully reusable; it have been considered, some of which will be would have no disposable external propellant discussed later. tank. The principal factor that governs the cost The PLV orbiter would be very much like the and effectiveness of in-space construction is current space shuttle, but would employ a pas- generally accepted to be the productivity of senger-carrying module in the payload bay. the construction crew and cost, and require- Like the shuttle, it would also use a disposable ments for shielding. The replacement of some external propellant tank, but a somewhat crew by automated equipment is therefore a smaller one. It couId carry 75 passengers, plus major consideration in alI construction strate- the normal shuttle crew. gies or scenarios, e.g., effort has already been devoted to automatic beam-building sys- A fleet of COTV, all reusable, would make 17 tems. The use of teleoperators and robot ma- the round trip from LEO to CEO, carrying the nipulators for assembly of large structures has cargo payloads up to CEO and returning also been considered. The current growth of empty to LEO for reuse. They would be pro- technology in these areas is extremely rapid, ’8 pelled by efficient but slow electrostatic and incorporation of such techniques would engines. Using low-thrust electric propulsion almost certainly benefit all aspects of SPS con- would require very long trip times, of the order struction. Despite the wide range of construc- of 4 to 6 months. The bases for selecting this tion options, estimated personnel require- propulsion option were essentially minimum ments for them are approximately the same: cost and ready availability of the argon pro- 19 750 & 200. pellant and other materials. Such long trip times, although suitable for cargo, are clearly GROUND-BASED CONSTRUCTION , not acceptable for personnel, so a high-thrust Building the rectenna, although a very large propulsion approach was chosen for the and relatively unique structure, nevertheless POTV. The design utilizes a basic oxygen- would involve far fewer uncertainties than hydrogen propulsion stage now undergoing constructing the space segment. A detailed research evaluation at NASA as part of its Ad- analysis 20 of both the basic structure and vanced Space Engine program. It employs construction aspects concluded that the pri- essentially the same level of “technology as mary structural material should be galvanized that used in the current space shuttIe main or weathering steel rather than aluminum engine. It could carry up to 160 people from (which is more scarce and requires a higher LEO to CEO and back, or 98 tonnes (480 man- energy cost to produce). months) of consumables from LEO to CEO. Because it would be impractical to launch a SYSTEM OPERATION full-sized power satellite by single launch vehi- An active control system would be needed cle, a strategy for constructing the satellite in both to keep the satellite in the proper orbit Earth orbit would be necessary. The basic space construction strategy selected for the ‘Denls j Powell and Lee Brewing, “Automated Fabrication of Large Space Structures, ” Astronautics and Aeronautics, October reference system is to launch all materials, 1978, pp 24-29 components, and people to staging areas in ‘ 8 Antal K Bejczy, “Advanced Teleoperators,” Astronautics LEO (fig. 15). The COTVs, because of their and Aeronautics, May 1979, pp. 20-31 “W H Wales, “SPS Program Review Transportation Perspec- large solar arrays, would be assembled in LEO tive, ” I n The Final Proceedings of the Solar Power Satellite Pro- as well. The main construction base would be gram /?ev/ew, DOE/NASA Conf-800491, July 1980 O located in CEO, although not necessarily at ‘ ’’ Feaslbil ity Study for Various Approaches to the Structural Design and Arrangement of the Ground Rectenna for the Pro- the eventual geostationary-orbit location of posed Satellite, ” NASA contract No. NAS-I 5280, Bovay Engi- the operational SPS. Hence the LEO staging neers, In{ , May 1977

Ch. 5—Alternative Systems for SPS ● 73

Figure 15.—SPS Space Transportation Scenario

SOURCE: W. H. Wales, “SPS Program Review Transportation Perspective,” in The Final Proceedings of the Solar Power Satellite Proqram Review, DOE/NASA Conf-800491, July 1980. -

(stationed above the rectenna) and to maintain costs, partly because of the predictability of the solar array’s orientation to the Sun. The the space environment as compared, for exam- mass of the necessary control system is esti- ple, with the uncertain environment in which mated at 200 tonnes; its average electric power aircraft structures must be designed to oper- consumption would be 34 MW. ate, and partly because of the extensive body of applicable design, testing, and operational Because of its low coefficient of thermal ex- experience with high-performance aerospace pansion and relative stiffness, a graphite com- structures. However, questions of dynamic in- posite structural material was selected for the stability resulting from Iow-probability occur- reference system in preference to the alumi- rences such as major meteor strikes or aggres- num alloys so widely used in aerospace struc- sive military action would have to be eval- tures. Although a complex engineering prob- uated. lem and, furthermore, one not readily subject to testing at an adequate scale prior to deploy- Orientation of the transmitting antenna rela- ment in space, it does not appear likely that tive to that of the solar array would be main- dynamic stability would cause any major unex- tained via the large rotary joint. Physical aim- pected problems in either performance or ing of the antenna itself would be accom-

83-316 0 - 81 - 6 74 ● Solar Power Satellites

plished by gyroscopes, which would feed concept, there are many technical uncertainties trol signals to the mechanical-joint turntable associated with the reference system. This sec- so that it could follow the antenna pointing re- tion identifies specific issues or problems in quirements. However, mechanical pointing of the reference system that would be of impor- the antenna would not have to be performed tance in formulating decisions concerning the with high accuracy, since the electronic phas- research, evaluation, development, demon- ing and pointing of the antenna subarrays stration, and deployment of satellite power would be insensitive to angular deflections of stat ions. the antenna of upto100. ● Performance. A major issue in the reference In addition to the equipment for satellite system design is the tremendous scale of the station keeping and attitude control, it would satellite. The level of 5 GW (net output be necessary to provide routine maintenance power) is based on scaling assumptions that of both the space and ground segments. Poten- could be subject to considerable change tial maintenance problems in the space seg- (e.g., the transmission frequency, the an- ment, in addition to the expected routine re- tenna and rectenna power densities); multi- placement of components, include the effects ple rectennas served by a single satellite also of solar wind, cosmic rays, micrometeoroids, constitute a potential variation. and impacts by station-generated debris. Aside ● The overall efficiency of the entire system from the solar wind and cosmic radiation ef- would be subject to considerable variation fects on solar cells, which would require active either up or down, and would be a key factor annealing of the silicon cells, none of these ef- in all cost and technology tradeoffs. Al- fects would appear to introduce significant though all system elements would involve maintenance problems or costs, based on ex- known technology, there is considerable un- tensive past and current experience with oper- certainty about how their efficiencies might ational satellites powered by photovoltaic add up when assembled together. celIs. ● Powerplant lifetime, assumed to be 30 years Repair and replacement of the solar blan- for the reference system, could actually be kets and more than 100,000 70-kW klystrons in greater or less depending on a number of the transmitting antenna are estimated to re- economically interrelated factors (e. g., ease quire a crew of from 5 to 20 people at the 21 of replacement of damaged components, geostationary orbit construction base, along sudden technological advances in compo- with the necessary transportation, support, nent efficiencies, etc.) This would affect all and resupply (e. g., station-keeping propellant) economic projections, even allowing for services. high-discount rates. Maintenance requirements of the rectenna ● The total mass in orbit, one of the critical and substation are also primarily associated parameters in assessing costs and launch- with repair and replacement of their biIIions of related environmental impacts, depends on components. Although a certain degree of re- a number of factors stilI subject to consider- dundancy is built into the system, a mainte- able variation. The power CoIlection/conver- nance crew would still be required to replace sion system is an obvious factor; the refer- storm-damaged rectenna sections and routine ence system’s two photovoltaic options are failures of both rectenna and substation equip- indicative of the significance of that trade- ment. off. The antenna mass is also important. Technical Uncertainties of Prospects for revising the reference-system’s the Reference System 100:1 ratio of rectenna-to-antenna area could have major impact on the overall sys- Although most observers accept the basic tem cost and performance. The 25-percent scientific feasibility of the SPS system con- contingency factor is another major factor 2’ DOE, op cit subject to revision if R&D mature. Ch. 5—Alternative Systems for SPS ● 75

SPS would require an extensive program of Silicon cells are subject to serious degra- research and testing of the numerous satellite dation by high energy electrons and pro- and terrestrial components of the system tons in the solar wind released by solar before planning for a demonstration satellite flares. One study” estimates that the ac- could be completed. In addition, substantial cumulated particle damage would de- improvements in components and overall tech- grade the output from the cells by 30- nology would have to occur before the SPS percent during the 30-year nominal life of could meet the performance specifications of the satellite. The resulting damage could the reference system. However, the current be repaired periodically by annealing the reference system does not constitute a pre- cells by either a laser or an electron beam. ferred system. It is, perhaps, technically feasi- The beam would sweep across the surface ble but certainly not an optimum design. It was of the cells and heat them briefly to sev- chosen by NASA/DOE as a model and a refer- eral hundred degrees centigrade. Very lit- ence to be used in the assessment process. As tle is known about either process in the such it has the inherent I imitation that as new laboratory and nothing at ail about how information becomes available the design be- they would work in space or how much comes progressively obsolete. energy they would use to anneal the surface of the photovoltaic cells. However, The following items summarize the major experiments have shown that annealing technical uncertainties for the reference sys- by electron beam is much more efficient tem and suggest possible ways to alleviate 23 than laser annealing. Because no long- them. term studies have been done, the suita- . Photovoltaic cells. The reference system bility of silicon cells for extended dura- specifies a silicon solar cell efficiency of tion space applications is in question; 17-percent and a mass of 2 grams per peak however, they have demonstrated ex- watt (g/Wp). Current space-rated single cellent performance over a period of crystal silicon cells operate at 12- to 16- about 10 years in operating spacecraft. percent efficiency. However, they are GaAs cells appear to be a more realistic about nine times as massive (18 g/Wp) as candidate for a reference-type satellite, called for in the reference system and though they have received much less at- they cost about $70/Wp (1980). The refer- tention than the silicon cells. GaAs cells ence system assumes a cell cost of about reach higher efficiencies and can operate $0.17/Wp. Although the issue of costs will at higher ambient temperatures than sili- be addressed in more detail in a separate con cells. Laboratory models of GaAs section, it is clear that meeting all three cells have reached efficiencies as high as goals for the silicon cell blanket would 18 percent.24 Because of their currently present manufacturers of current cell higher unit cost, the GaAs array would technology with an extremely difficult probably require refIectors to concentrate task. Normal advances in cell production the Sun’s rays on the cells and thereby techniques would readily result in the reduce the required cell area. Aluminized necessary efficiency increase. However, Kapton has been suggested as a reflective the burden of achieving a nine times material because of its low thermal coeffi- reduction in weight along with a reduc- cient of expansion and low mass density. tion in costs of a factor of 400 makes it highly unlikely that an SPS could be built 2*C R Woodcock, “SPS Silicon Reference System,” The Fina/ using single crystal silicon cells. Proceedings of the Solar Power Sate//ite Program Review, If efficiency-mass-cost goals were met, DOE/NASA Conf-800491, July 1980, there would still be the problem of cell “B E. Anspaugh, J. A Scott-Monck, R. G. Downing, D W. Moffett, and T. F Miyahira, “Effects of Electrons & Protons on lifetime in space and the related problem Ultra Thin Silicon Solar Cells, ” J PL contract No, NAS7-1OO. of the feasibiIity of annealing the surface. “lbld 76 . Solar Power Satellites

Here, again, whether Kapton and GaAs natives to the klystron may provide better cells can maintain their integrity over the noise and harmonic control (see section 30-year design lifetime of the satellite is on alternatives below). unknown. Considerably more study would ● Space transportation. The problems inher- be needed to determine the feasibility of ent in developing the capability to trans- this option. port SPS components to LEO and CEO are ● Space charge and plasma effects. Because those of extending a mature technology, of the high voltages associated with oper- i.e., there is sufficient understanding of ation of the klystrons, electrical charge the problems to be faced that there is lit- buildup in the satellite components could tle doubt that the appropriate vehicle cause arcing and subsequent failure of could be developed. The most important certain components. question is whether the necessary massive ● Rotary joint/slip rings. Although the basic loads could be transported for sufficiently technology of building a rotary joint and low costs, i.e., would reusable vehicles an associated slip ring (for electrical con- prove economic? In this area, much can tinuity) is well-known, considerable uncer- be learned from experience with the shut- tainty surrounds their construction and tle operation on the scale of the reference I n addition to economic concerns, there satellite in a space environment. Because are additional technical questions relating it would operate in a gravity-free environ- to environmental effects that would re- ment, the design demands would be dif- quire study. For instance, can the launch ferent than they are for terrestrial designs. vehicles fly trajectories that would keep ● Klystrons. Current klystrons last about 10 the effects of ionospheric contamination years, but these are tubes especially se- to a minimum? Would it be possible to lected for their long life characteristics substitute other technologies for the and they operate at much lower power argon ion engine proposed for the refer- levels than the 70 kW required of reference system (see ch. 8). ence system klystrons. High-power klys- ● Construction, operations, and mainten- trons do exist, but they operate in a pulsed ance. There are unresolved questions mode, not continuously as the reference about the productivity of humans and ma- system klystrons would have to. The an- chines in the space environment. Some tenna’s phased array control system automated equipment has been built and would need considerable development tested on Earth, but considerable develop- and testing. Although pilot beams have ment would be needed to choose the best been used in other applications, and the ratio between automated and human technology is therefore known, it is tasks. unclear whether the power beam would leave the ionosphere sufficiently unaf- fected to allow for undisturbed passage of Alternatives to the Reference the pilot control beam. System Subsystems Although harmonics and other noise One of OTA’s goals is to explore the possible produced by the klystron or alternative alternatives to the reference system. Some op- transmitting device would seem unlikely tions improve specific components of the ref- to affect the natural environment adverse- erence system. Others would require signifi- ly, they could cause radio frequency inter- cant redesign of the overall system. This is ference for communications systems (see because the reference system is composed of a the discussion of ch. 8). This problem number of interlocking components, some of might be severe and wouId need extensive which depend heavily on the other elements of study, but most experiments could be car- the system. Thus, a radical change in one com- ried out in ground-based testing. Alter- ponent might require numerous other system Ch. 5—Alternative Systems for SPS • 77

changes in order to create the most efficient ● Photoklystron. This device, which is stilI in overall design. the very early stages of study, both converts the sunlight directly to microwave A number of alternative subsystems and sys- power, and transmits it. If successful, it tems were considered in the process of elect- could replace both photovoltaic cell and ing the reference system design. Advances amplifier. have been made in some components that ● Offshore rectennas. For highly populated were previously rejected. In addition, consid- European and U.S. coastal areas, recten- eration of some of the above-mentioned tech- nas mounted in the shallow offshore sea- nical uncertainties has engendered new de- beds offer some advantages over long signs that could alleviate these uncertainties transmission lines from suitable land- or resolve some of the technical problems en- based rectennas. countered in the reference system. The following summary lists a number of THE SOLID-STATE SYSTEM subsystem options that could be considered as Two system approaches using solid-state alternatives to the reference system. A more devices have been considered for the SPS. The detailed discussion of each can be found in ap- most direct of these simply replaces the kyls- pendix A. trons and slotted waveguides in the reference Solar thermal power conversion. Either a system by solid-state amplifiers and dipole Brayton- or Rankine-cycle engine offers antennas maintaining essentially the same higher efficiency energy conversion than basic configuration as that of the reference photovoltaics. However, they currently system (fig. 9); the second approach complete- suffer from limitations on the means for ly revises the satellite configuration by inte- heat rejection. grating the antenna and solar array in the Thermionic, magnetohydrodynamic Earth-facing “sandwich” configuration, using a or wave energy exchanger technologies movable Sun-facing mirror to illuminate the might eventually find use in combination solar array (fig. 16). A number of alternative with the Rankine or Brayton cycle. sandwich configurations have been explored Photovoltaic alternatives. Materials other but at the moment the configuration of figure than silicon or gallium arsenide may even- 16 seems to be the best.25 tually prove more viable for use in the Another related subsystem option uses the SPS. Currently none of the other obvious multibandgap photovoltaic cells discussed options meet the projected standards for earlier, possibly in conjunction with selective efficiency, low mass, materials availabili- filtering to reduce solar-cell temperatures. ty, etc., that would be needed for satellite When such cells are utilized in the sandwich use. Different sorts of concentrator sys- configuration of figure 16, they offer consid- tems are also of interest, as is the possi- erable potential mass reduction. A recent pre- bility of using single cells or a combina- liminary case study26 compared sandwich-type tion of cells that respond to a wide por- systems such as that of figure 16 employing tion of the solar spectrum. A possible ap- single-bandgap GaAs photocelIs similar to proach would be to use a combination of those of the reference system but having high- al I these variations. er concentration ratios (CR) with optimized Alternative microwave power converters. multibandgap photovoitaics. Such a configu- Several devices other than the klystron ration would result in an approximate W-per- have been considered for converting elec- cent increase in power delivered per kilogram. tricity to microwaves and transmitting them to Earth including the magnetron, which offers the principal potential ad- “G M Hanley, et al , “Satellite Power Systems (SPS) Concept vantage of cost and low noise, and the Deflnitlon Study, ” First performance Review, Rockwell international report NO SSD79-01 63, NASA MSFC contract No solid-state amplifier whose reliability NAS8- )2475, Oct 10, 1979 could be very high and mass low. ~bl bld

78 ● Solar Power Satellites

Figure 16.—The Solid-State Variant of the Reference System

Sunlight I

Reflected sunlight Detail of solar cell blanket panel

Solid-state amplifier panel

Microwave / power to Earth /’ Solar array/microwave antenna sandwich panels

SOURCE: G. M. Hanley, et al., “Satellite Power Systems (SPS) Concept Definition Study, “First Performance Review, Rockwell International report No. SSD-79-0163, NASA MSFC contract No. NAS-8-32475, Oct. 10, 1979.

LASER TRANSMISSION

Lasers constitute an alternative to micro- ● The use of low Sun-synchronous rather wave transmitters for the transmission of than high geostationary orbits for the mas- power over long distance.27 They offer the fun- sive space power conversion subsystem damental advantage that at infrared wave- might be possible. (A Sun-synchronous or- lengths, energy can be transmitted and re- bit is a near-polar low orbit around the ceived by apertures over a hundred times Earth that keeps the satellite in full smaller in diameter than the microwave beam. sunlight all the time while the Earth ro- This obviously would reduce the size and mass tates beneath it.) In this suggested system, of the space transmitter and the land-area re- the laser would beam its power up to low- quirement of the ground receiver. But perhaps mass laser mirror relays in geostationary even more important, the great reduction in orbit for reflection down to the Earth aperture area would permit consideration of receiver, an arrangement that might con- fundamentally different systems. For example: siderably reduce the cost of transportation, since the bulk of the system mass is in LEO rather than in GEO. However, sys- W H power Satellites: The Laser Option,” Astronautics and Aeronautics, tem complexity would be increased due March 1979, pp. 59,67, to the need for relay satellites. Ch. 5—Alternative Systems for SPS ● 79

● Because the mass of the laser transmitters beam) from about 1 to nearly 50 percent dur- would not dominate the satellite, as does ing the past decade. the reference-system microwave transmit- Of all the currently operating CW lasers, ter, laser satellites would not benefit near- 29 only the electric discharge laser (EDL) seems ly so much by large scale as the reference a feasible alternative for the SPS. The gas dy- system satellites. The resulting smaller namic laser (CDL) suffers from very low effi- systems would improve the flexibility of ciency if used in the closed cycles necessary terrestrial power demand matching, pro- for space (i.e., the gas supply must be circu- vide high degrees of redundancy, permit a lated, cooled, and reused). Chemical lasers re- smaller and therefore less costly system quire a continuous propellant supply that demonstration project, and might even makes them also unsuitable for long-term use preclude the need for ultimate develop- in space. ment of an HLLV. ● The small size of the receiving station High-power density at 50-percent conversion would make it possible to employ multi- efficiency levels has been achieved for EDLs, ple locations close to the points of use, but only in the open-cycle mode for short time thereby simplifying the entire ground dis- periods. The closed-cycle systems needed for tribution and transmission system. It SPS have yet to be tested, even in the labora- would also open up the possibility of tory. In theory, they should achieve high effi- repowering existing powerplants, regard- ciencies in that mode as well, but considerable less of their size, simply by replacing their improvement in the available technology steam generating units with laser-heated would be required to reach the necessary boilers and/or superheaters. goals. The most important technical disadvantages In addition to using improved designs of cur- of laser-power transmission are the very low rently operating lasers, several advanced con- efficiencies of present laser-generation and cepts have been suggested. Of these, the solar- power-conversion methods, low efficiency of pumped laser and the free electron laser (FEL) laser transmission through clouds and mois- seem most promising for the long term. ture, and the relatively undeveloped status of ● Solar-pumped lasers. Figure 17 illustrates laser power-system technology in general. the concept of a solar-pumped laser. The The laser system would consist of three energy contained in sunlight directly ex- distinct elements: the laser-generation sub- cites a combination of gases confined be- system, the laser-to-electric power-conversion tween two mirrors, which subsequently subsystem, and the laser beam itself. “lase” and transmit the captured energy. It suffers the drawback that because only Laser Generators a part of the solar spectrum is useful in exciting any given Iasant gas, its conversion Although the laser has become a well-known efficiency is likely to be fairly low. How- and widely utilized device in industry, the ever, elimination of the need for a sepa- high-power continuous-wave (CW) laser gen- rate electric power-generating system, erators needed for SPS are still in the and the consequent reduction in mass and advanced-technology or, in many cases, the complexity, could more than compensate 28 early research phase. However, the technol- for this drawback. Further, in comparison ogy is improving dramatically as exemplified with other laser systems, the solar- by the growth of laboratory-demonstrated con- pumped laser’s efficiency need be only as version efficiencies (input power to laser good as the combined power-generating

28j Frank Coney bear, “The Use of Lasers for the Transmission “G W Kelch and W. E. Young, “Closed-Cycle Gasdynamic of Power, ” in Progress in Astronautics, vol. 61, A IAA, N Y , Laser Design Investigation, ” Pratt & Whitney Aircraft, NASA )ui~ 1978, pp. 279-310 Lewis Research Center report No CR-135530, Jan 1,1970. 80 • Solar Power Satellites

Figure 17. —Indirect Optically Pumped CO/CO2 Mixing Laser

Q Ps SEP solar n

SOURCE: R. Taussig, P. Cassady, and R. Klosterman, “Solar Driven Lasers for Power Satellite Applications,” in Firra/ Pro ceedings of SPS Program Review, Department of Energy, p. 267

system and laser generator of other laser Free-Electron Lasers (FEL) systems (about 7.5-percent for a photo- An FEL is powered by a beam of high-energy voltaic-powered carbon monoxide (CO) electrons oscillating in a magnetic field in such EDL30). a way that they radiate in the forward direc- Although the information exists to deter- tion (fig. 18). A number of pulses reinforce the mine the applicabiIity of solar-pumped lasers stored light between the mirrors, generating a to SPS, adequate studies have not been done. coherent laser beam. The high-energy density There is as yet little or no realistic basis for the of the relativistic electron beam is theoreti- mass, efficiency, and cost projections pro- cally capable of producing very high-power posed by several authors.31 32 33 34 density lasers, and the emitted frequency is tunable simply by changing the electron ‘“R. E. Beverly, “Satellite Power Systems (SPS) Laser Studies energy. Technical Report, Vol. 1, Laser Environmental Impact Study,” Rockwell International SSD-80-0119-I, August 1980 Although efficiencies are theoretically pro- “W. S. Jones, L. L. Morgan, J. B, Forsyth, and J Skratt, “Laser Power Conversion System Analysis: Final Report, Vol. I l,” Lock- jected to be quite high (around 50 percent for 35 heed Missiles and Space Co., report No LMSC-D673466, NASA the combined FEL and storage ring ), it is not report No. CR-1 59523, contract No NAS3-21 137, Mar 15, 1979 known whether such efficiencies could be 32 Claud N Bain, “Potential of Laser for SPS Power Transmis- reached in practice. In addition, the system sion, ” report No R-1 861, PRC Energy Analysls Co , DOE contract No. EG-77-C-01-4024, September 1978 mass per unit power output and the ability to 3JJohn D. G. Rather, “New Candidate Lasers for Power Beam- ing and Discussion of Their Appl icatlons, ” I bid,, pp. 313-332. ‘5John W Freeman, William B. Colson, and Sedgwick Simons, 34 Daryl J. Monson, “Systems Efficiency and Specific Mass Esti- “New Methods for the Conversion of Solar Energy to R. F. and mates for Direct and Indirect Solar-Pumped Closed-Cycle High- Laser Power, ” in Space Manufacturing ///, Jerry Grey and Energy Lasers in Space,” ref 105, pp 333-345 Chrlstlne Krop (eds ) (New York AlAA, November 1979). Ch. 5—Alternative Systems for SPS ● 81

Figure 18.—The CATALAC Free Electron Laser Concepts

SOURCE: R. Taussig, P. Cassady, and R. Klosterman, “Solar Driven Lasers for Power Satellite Applications,” in Final Pro- ceedings of SPS Program Review, Department of Energy. p. 267 scale to the size and power levels of a laser Transmission of the laser beam through the SPS are impossible to predict reliably at this atmosphere is also affected by a phenomenon time. 36 called “thermal blooming;” i.e., heating of the atmosphere that causes it to act Iike a lens and Laser Transmission distort the laser beam. Scientists are currently divided on the significance of this issue and As in the case of microwave transmission, opinions range from assertions that it is a ma- the fundamental parameter that governs much jor factor38 to suggestions that it could of laser transmission performance is the fre- be avoided altogether by selecting the trans- quency (or wavelength). At ultraviolet or visi- mitting wavelengths carefully.39 Considerable ble wavelengths, absorption losses in the at- classified research is now being carried out on mosphere are higher than for infrared wave- this effect in connection with laser-weapons lengths. The wavelength also affects the effi- research. Some of this work might be applica- ciency of the laser power absorption and con- ble to SPS use, though in general the military version equipment. lasers are pulsed, not CW systems. The differ- At the wavelengths of CO or CO, EDLs, (5 to ence could be critical and should be studied 10 microns), the primary mechanism of beam carefulIy. attenuation is molecular absorption. Scatter- With regard to laser optics, it is important to ing by molecuIes or by aerosols in clear air is develop components capable of low-loss, high- relatively unimportant. Attenuation of the power-density transmission and reflection of beam by aerosols under hazy or cloudy condi- laser light.40 It appears that adequate tech- tions is quite significant and can completely nology for SPS systems has a high probability block the beam if the clouds are thick enough. of being available within the next 20 to 30 Although it is apparently possible to burn a years, due primarily to advances being made in 37 hole through thin clouds, the attenuation of current military laser research and technology energy is appreciable, and because clouds are programs. seldom stationary, the laser would continually encounter new water droplets to vaporize.

‘s Beverly, op. cit. “Jones, et al , op cit 37E. W. Walbridge, “Laser Satellite Power Systems, ” Argonne “Beverly, op. cit National Laboratory report No AN L/ES-92 40 Baln, op cit 82 Ž Solar Power Satellites

Transmission options for SPS lasers are eral lasers making up the beam, and each essentially of two types: a narrow, highly con- beam by itself would transmit far too little centrated beam or a wide, dispersed beam (fig. power to cause any problems. Adaptive optics 19). Advantages of the narrow beam are the systems are being studied for use in military reduced land area needed and the smalI size of directed energy weapons and look promising.” the ground power-conversion system; prob- It should be emphasized that the overall sys- lems include potential environmental and tem constraints might be quite different for safety impacts of the high-intensity beam, con- the large CW lasers needed for SPS than for cerns over military uses, and the need for so- pulsed military examples. phisticated high-temperature receivers and power-conversion equipment. Advantages of Laser-Power Conversion at Earth the dispersed beam are its less severe environmental impact, the possible use of low-per- Several approaches are possible for convert- formance optics, and simplicity of low-power- ing high-energy-density laser radiation to use- density receiving systems. Disadvantages in- ful electric power. The technology of laser clude relatively high atmospheric dissipation, energy converters is relatively new, but prog- larger land area required and the large mass of ress has been rapid. Laboratory models have Earth receptors. It is probably too early to achieved conversion efficiencies of 30 to- 40 make an informed selection between the two percent and designers project eventual effi- options, but the narrow-beam approach ap- ciencies of 75 percent for some versions. Table pears to offer the principal benefit compared 6 summarizes the available technology and 42 to reference-system microwave transmission. projects future potential efficiencies. A final concern is the ability to point and The Laser-Based System control the beam to make sure it would always remain within the designated receiver area and Lockheed 43 has generated one possible laser to shut it off instantly should it stray. The system (fig. 20) that utilizes power satellites in adaptive-optics approach to beam control 4’Claud N Bain, “Power From Space by Laser,” in “High-Pow- (e.g., phased-array) such as would be used for ered Lasers In Space, ” Astronautics and Aeronautics, vol. 17, the microwave beam, appears adequate to March 1979, pp 28-40 provide the necessary pointing accuracy and “(;eorge Lee, “Status and Summary of Laser Energy Conver- sion, ‘ In Progress in Astronautics, VOI 61 Al AA, N Y , July to ensure safety, since any loss of phasing con- 1978 pp 549-565 trol would cause loss in coherence of the sev- 4’Jones, et al , op clt

Figure 19.—Optics and Beam Characteristics of Two Types of Laser Power Transmission System (LPTS) Concepts

Optics Optics m

SOURCE: Claud N. Bain, “Potential of Laser for SPS Power Transmission,” report No. R-l WI, PRC Energy Analysis Co., DOE contract No. EG-77-C-01-4042, September 1978. Ch. 5—Alternative Systems for SPS ● 83

Table 6.—Projections for Laser Energy Converters in 1981-90

Current 1981-90 Photovoltaics...... —30% efficiency —45% efficiency —megawatt power levels —megawatt power levels —wavelengths below 1 micron —wavelengths below 1 micron Heat engines ...... —Piston engine: Otto or diesel cycles —Turbine —50% efficiency —75% efficiency —1-10 kW —megawatt power levels —wavelengths near 10.6 microns —wavelengths near 5 microns Thermionics ...... —40% efficiency —50% efficiency —1-10 kW —megawatt power levels —wavelengths near 10.6 microns —wavelengths near 5 or 10 microns Photochemical cells ...... —Photoassisted dissociation of water —Photoassisted dissociation of water —15Y0 efficiency —30% efficiency —wavelengths near 0.4 microns —wavelengths near 0.6 microns Optical diodes ...... —Evaporated junction arrays — Evaporated junction arrays —not ready to convert power —50% efficiency —megawatt power levels —respond to wavelengths from UV to over 10 microns

SOURCE: George Lee, “Status and Summary of Laser Energy Conversion, “ in Progress in Astronautics, vol. 61, AlAA, N. Y., July 1978, pp. 549-565. low Sun-synchronous orbit and relay satellites the significant difference in space basing (i. e., (laser mirrors) both in LEO and CEO. One geo- LEO rather than CEO) which it presents com- stationary relay serves each power satellite. pared to the reference system. Because of the Based on an analysis of five candidate systems significant uncertainties present in the laser in three power ranges, Lockheed selected a systems concepts and the relative lack of tech- CO, EDL powered by a wave energy exchanger nology base for laser devices, the optimum (EE) binary cycle and a similar binary cycle for laser system would undoubtedly look rather ground power conversion. different from any system so far devised. The specific 500 MW system selected is dia- A laser system that used photovoltaic arrays gramed in figure 21; hardware details of the to collect and convert the Sun’s energy would power satellite appear in table 7, and the Over- . suffer from the fundamental difficulty that the all system characteristics are summarized in overalI efficiency of the system wouId be quite table 8. low compared to projected reference system efficiency .45 The major limiting factors are the A major potential advantage of the laser projected efficiencies of the laser itself (50 per- system is that it could be demonstrated via a cent for an EDL), the atmospheric transmis- subscale 500-kW pilot program using the space sion (84 to 97 percent), and the conversion effi- shuttle to deliver the power and relay satellites ciency of the terrestrial receptor (40 to 75 per- into LEO orbits. cent). When multiplied together with the Other laser systems are possible. For exam- higher efficiency of other system components, ple, Rockwell44 has investigated a geosyn- they result in an overall efficiency of 17 to 36 chronous laser SPS powered by photovoltaic percent after photovoltaic conversion of sun- ceils and using 20 to 24 100-MW CO EDL light to electricity to power the laser. When the lasers. The CO laser was chosen because it has efficiency of the solar cells (17 percent) is greater overall efficiency and is lighter than a taken into account, the overalI system efficien-

C02 laser. cy falls to only 2.8 to 6 percent compared to the projected reference system efficiency of 7 This study will use the LEO-based C0 laser 2 percent. Although this decrease would con- system in its subsequent analysis because of

‘*Beverly, op. cit. 45D0E, op. cit.

Ground site SOURCE: W. S. Jones, L. L. Morgan, J. B. and J. “Laser Power Conversion Analysis: Final Report, Vol. Lockheed Missiles and Space Co., report No. NASA report No. CR-159523, contract No. 137, Mar. 15, 1979.

Figure 21 .—Components of the Laser Concept

Synchronous relays

Occulted , Power

SOURCE: W. S. Jones, L. L. Morgan, J. B. and J. “Laser Power Conversion System Analysis: Final Report, Vol. 11,” Lockheed Missiles and Space Co., report No. NASA report No. CR-159523, contract No. 137, Mar. 15, 1979 Ch. 5—Alternative Systems for SPS • 85

Table 7.—500 MWe Space Laser Power System

Power generation Spacecraft, EE/binary and structure, Transmitter aperture Collector Solar cavity cycle conditioning Laser radiators, etc. and optical train Unit efficiency (%) . . . . . 85 86 73.5 93.1 23 — 98.7 System efficiency (%) . . 85 73.1 53.7 50.0 11.5 — 11.4 Power in (MW)...... 7,913 6,726 5,784 4,251 3,958 — 910 Power out (MW)...... 6,726 5,784 4,251 3,958 910 — 899 Orbital weight (kg) . . . . . 242,850 517,750 1,326,330 717,660 1,809,000 128,653 97,811 Spacecraft 4,108 Telescope (2) 89,812 Structure 94,433 Beam reduction 5,379 Radiators 6,032 Phasing array 1,539 Stabilization Optical train 1,181 24,080

Space Atmospheric Ground Thermal Binary Electrical transmission Space relay transmission receiver cavity cycle generation Unit efficiency (%) . . . . . 95 99 85 96 98 75.5 98 System efficiency (%) . . 10.8 10.7 9.1 8.7 8.5 6.5 6.3 Power in (MW). , ...... 899 854 845 718 690 676 510 Power out (MW)...... 854 845 718 690 676 510 500 Orbital weight (kg) . . . . . – 105,438 — — — — — Transmitter 44,703 Receiver 46,729 Optical train 945 Spacecraft 5,900 Radiators 5,762 Structure 1,023 Miscellaneous 376

SOURCE: W. S. Jones, L. L., Morgan, J.B. Forsyth, and J. Skratt, “Laser Power Conversion System Analysis: Final Report, Vol. 11,” Lockheed Missiles and Space Co., report No. LMSC-D673466, NASA report No CR-159523, contract No. NAS3-21 137, Mar 15, 1979.

Table 8.—Laser Power Station Specification stitute a potential problem for the laser system, it must be emphasized that many other Solar power collected (MW)...... 7,913.0 Collector diameter(m)...... 2,710.0 complex factors (e. g., the smaller terrestrial Electrical power to laser(MW) ...... 3,958.0 receivers, or lower mass in GEO), might com- Laser power output (MW) (20 lasers pensate in complex ways for lower efficiency. at 45.5 MW each)...... 910.0 Transmitter, aperture diameter (m)...... 31.5 When added up, the combination might make Secondary mirror diameter (o)...... 3.0 the laser system more acceptable overall than Transfer mirror size (m) ...... 3.0 x 4.2 the microwave systems. ’b Mirror reflectivity (%)...... 99.85 Optics heat rejection (MW) ...... 11.8 Radiator area (m2)...... 2,656.7 Mirror operating temperature (“C) ...... 200.0 “Abraham Hertzberg and Chan-Veng Lau, “A High-Tempera- ture Ranklne Binary Cycle for Ground and Space Solar AppIica- SOURCE: W. S. Jones, L. L., Morgan, J. B. Forsyth, and J. Skratt, “Laser Power tions, ” m “Radiation Energy Conversion in Space, ” K W, Conversion System Analysis: Final Report, Vol. 11,” Lockheed Missiles and Space Co., report No. LMSC-D673466, NASA report No. Billman (cd,), Progress in Astronautics and Aeronautics, vol. 61 CR-159523, contract No. NAS3-21137, Mar 15, 1979. (New York, AlAA, July 1978), pp 172-185. 86 . Solar Power Satellites

MIRROR REFLECTION

Instead of placing the solar energy conver- increasing the orbit altitude and mirror size, sion system in orbit as in the reference SPS, which increases the size of the illuminated several authors have suggested using large or- ground circle and thereby permits the use of biting mirrors to reflect sunlight on a 24-hour larger ground stations.52 The orbiting mirrors basis to ground-based solar-conversion sys- themselves could probably be quite large (up tems. 47 48 49 50 to 50 km’ each) with very low mass density53 and still maintain their required optical sur- Typically, this option would use plane mir- face flatness in the presence of disturbing rors (fig. 22) in various nonintersecting low- forces. altitude Earth orbits, each of which directs sunlight to the collectors of several ground- A mirror system would offer the following based solar-electric powerplants as it passes potential advantages: over them (the so-called “SOL ARE S“ concept). ● The space segment would be simple and Each mirror would be composed of a thin of low mass. It would consist only of film reflecting material stretched across a sup- planar reflective thin-film mirrors. porting structure made up of graphite-rein- ● It would minimize the need for large-scale forced thermoplastic. As they pass within space operations, since recent designs range of the terrestrial receiving station, the allow terrestrial fabrication and packag- mirrors would acquire the Sun and the ground ing with automatic deployment i n space. station nearly simultaneously. They would ● The system would be modular and highly maintain pointing accuracy by means of built- redundant, i.e., there would be many iden- in reaction wheels. tical mirrors capable of mass production. ● The mirrors would operate at low-orbit al- Two typical “limiting cases” have been iden- titudes, thus not requiring the CEO trans- tified from among several alternatives.51 one portation system of some other alterna- wouId use a 1,196-km circular equatorial orbit 0 tives. (O latitude) serving 16 equatorial ground sta- ● It would eliminate the need for develop- tions each generating about 13 CW (baseload, ing microwave- or laser-transmitting tech- with minimum storage) and another 6,384-km nology. 40 ‘-inclination circular orbit serving four 375 ● The mirrors would reflect ordinary sun- GW ground stations at 300 latitude. Additional light, thus eliminating many of the poten- ground stations in each case (to accommodate tial damaging environmental effects due demand growth) could be achieved simply by to laser or microwave transmission. ● It could be used for a variety of terrestrial 47 Hermann Oberth, “Wege zur Raumschiffahrt, ” Oldenburg- uses where enhanced 24-hour sunlight Verlag, Berlin, 1929; also see “Ways to Spaceflight, ” NASA technical translation TT F-662 wouId be useful. SOLARES couId increase 48 Krafft A Ehricke (for example), “Cost Reductions in Energy the solar product fivefold over the same Supply Through Space Operations, ” paper IAF-A76-24, 27th lrr- system operating on ambient sunlight. ternationa/ Astrorraut;ca/ Congress, Anaheim, Calif , Oct. 10-16, ● 1976. Demonstration would be very inexpensive “K, W. Billman, W, P Gilbreath, and S W Bowen, “introduc- compared to laser or microwave options. tory Assessment of Orbiting Reflectors for Terrestrial Power Gen- eration,” NASA TMX-73,230, April 1977 ‘“K, W. Billman, W. P. Cilbreath, and S W Bowen, “Orbiting Mirrors for Terrestrial Energy Supply, ” in “Radiation Energy Con- version in Space,” K, W, Billman (ed ), Progress in Astronautics ‘2K W Billman, “Space Orbiting Light Augmentation Reflec- and Aeronautics Series, VOI 61 (New York Al AA, July 1978), pp tor Energy System: A Look at Alternative Systems,” SPS Program 61-80 Review, June 1979. “K. W. Billman, W. P. Gil breath, and S W. Bowen, “Solar “John M Hedgepeth, “Ult[ ghtweight Structures for Space Energy Economics Revisited: The Promise and Challenge of Or- Power, ” in “Radiation Energy Conversion in SpaceJ” K W, Bill- biting Reflector for World Energy Supply,” DOE SPS Program man (ed ), Progress in Astronautics and Aeronautics, vol. 61 (New Review, June 8,1979. York Al AA, j uly 1978), pp. 126-135.

Ch. S—Alternative Systems for SPS ● 87

Figure 22.–The Mirror Concept (SOLARES)

Photo credit: National Aeronautics and Space Administration

SOURCE: W. Bill man, “Space Orbiting Light Augmentation Reflector -. System: A Look at Alternative Systems,” Review, June 1979.

On the other hand, mirror systems would ● The mechanisms needed to keep the mir- possess the following potential disadvantages: rors pointed accurately might be complicated. ● They would require a large number of satellites each with individual attitude con- ● The mirrors might cause unwanted weath- trol. Maintenance might be expensive and er modifications around the ground sta- difficult to accomplish. tions (see below and ch. 8). 88 ● Solar Power Satellites

● Scattered light from the mirrors and the Table 9.—SOLARES Baseline System light beams in the atmosphere would in- configuration: terfere with astronomical research (see Space system 2 ch. 8). 4,146km inclined orbit, 45,800km total mirror area Ground system ● The large power production per site (10 to 6 sites with DOE 1986 goal solar cells @ 15% efficiency 135 GW) and necessary centralization of 11 0/0 overall system conversion efficiency, ~~-circle the electrical supply from them would not area = 1.168km2 each, 135 GWe each be attractive to the utilities (see ch. 9). Impact: Total system would produce 3.24 times current U.S. con- ● 2 2 The large area of the receiving sites (100 sumption, total area = 84 x 84km (52 x 52 mi ) 2 to 1,000 km ) would be likely to make Baselined costs (in 1977 dollars) land-based siting extremely difficult if not Implementation schedule impossible from a sociopolitical stand- 5-year development, design, test, and evaluation (DDTE) 2-year manufacturing and transport fleet facilities point (see ch. 9). preparation 6-year space and ground hardware construction System complete about 1995 The Mirror System Direct costs estimate (billions of dollars) Facilities ...... $ 47.30 54 The “baseline” Mark 1 SOLARES design Hardware...... 885.65 (table 9) would require a total mirror area of Total direct ...... $932.95 2 2 Indirect costs estimate (billions of dollars) nearly 46,000 km . If each mirror were 50 km , 15% contingency on direct costs ...... $139.94 about 916 of them would be necessary for a Design, development, test, and evaluation ...... 43.80 global power system that would produce a Interest a: Facilities ...... 23.58 total of 810 GW from six individual sites, or Hardware ...... 101.26 about twice 1980 U.S. electric generation. It DDTE ...... 41.01 was chosen for comparative purposes because Total indirect...... $349.59 it demonstrates the potential for large scale Total cost ...... $1,282.54 Indirect cost factor...... 1.38 energy output that might be achieved with mir- Installed cost per rated output ($/kWe)b...... 1,508 rors. It is by no means the optimum SOLARES Capacity factor(%) ...... 95 system. A low-orbit version (altitude 2,000 km) 1995 O&M costs: with 15 smaller ground stations (10,000 to Fixed ($/kW-y)...... 3 Variable (mills/kWh)...... 2 13,000 MW output) might be more feasible or Levelized capital cost (mills/kWh)C ...... 27.2 Levelized O&M cost (mills/kWh)d ...... 4.5 desirable. One of the principal features of the e SOLARES concept is that it could be used for Levelized busbar energy cost (mills/kWh) ...... 31.6 any energy use where enhanced sunlight would Comparison baseload power systems (CIRCA 1995): Conventional coal/nuclear mixf be used to advantage. By using many more Levelized busbar energy cost (mills/kWh)e ...... 45 smaller mirrors, the mass per unit area could Ambient sunlight photovoltaicf g be minimized, and the total mass in orbit for Levelized busbar energy cost (mills/kWh)...... 115 the entire baseline system then becomes about a4Y@ first year, 8% per annum until positive cash flow after Year 11. blncludes all direct costs, 157” contingency, interest during implementation at 4X105 tonnes. Thus, the entire SOLARES 8% per annum. c15% fixed charge rate 30 years at 60/0 annual inflatiOn. baseline system would require only the same d30 years at 6% annual’ inflation, e15y& fixed charge rate. mass in space as eight 5,000 MW reference sys- fsee text; these d. not include their historically eXtenSive R&D costs that are tem satellites. Included, in SOLARES costing. 91Jses same terrestrial costing algorithm as SOLARES that results in indirect Several Earth-based energy production cost factor of 1.37. SOURCE: K. W. Billman, W. P. Gilbreath, and S. W. Bowen, “Solar Energy - methods currently under development might Economics Revisited: The Promise and Challenge of Orbiting Reflector for World Energy Supply,” DOE SPS Program Review, be used in conjunction with orbital reflector June 8, 1979. systems: 1 ) photovoltaic arrays of varying sizes are projected for commercial deployment in plants should become commercially feasible the late 1980’s, and 2) solar-thermal electric in selected locations about the same time, possibly also for “repowering” of existing coal- or oil-fired fossil-fuel plants with solar boilers. 54 Billman, et al., “Solar Energy Economics Revisited. The Promise and Challenge of Orbiting Reflector for World Energy Much of the economic disadvantage of both Supply, ” op. cit types of solar-electric powerplants is associ- Ch. 5—Alternative Systems for SPS Ž 89 ated with the energy storage needed to allow of the accelerated evaporation produced by them to serve as intermediate or baseload the high-intensity solar radiation. plants. Should these plants prove to be even If the orbiting mirrors can disperse clouds of marginally successful, relieving their storage moisture around the SOLARES ground station, needs by keeping them I it for 24 hours a day by what effects may they have on the climate sunlight from orbiting reflectors would en- nearby? Large orbiting mirrors have been sug- hance the attractiveness of these terrestrial op- 56 gested for use in climate modification, but tions. their possible detrimental side effects have not The various benefits of a mirror system must been studied (see ch. 8). However, even if be weighed against the percentage of time the reflected sunlight could be shown to have a ground-based energy production facilities salutary effect on certain regions of the Earth, would be obscured by clouds, smog, fog, and there is no reason to believe, without further other atmospheric obstruct ions. However, study, that regions whose weather patterns there is some evidence” that the concentrated could benefit from enhanced sunlight would sunlight provided by the orbiting mirrors necesssariIy coincide with the SOLARES would tend to disperse water-based obscura- ground stations. tions such as clouds and fog, as a consequence — *’I Bekey and J E Nagle, “Just Over the Horizon in Space,” “Ibid Astronaut/es and Aeronautics, May 1980.

SPACE TRANSPORTATION AND CONSTRUCTION ALTERNATIVES

Space transportation and construction (with shuttle size vehicles at high launch rates could the possible exception of SOLARES) are com- be cheaper than developing and using larger mon to all the options. NASA contractors who launch vehicles (see section on costs). Perhaps developed the transportation, construction, the most obvious approach is to upgrade the and assembly plan for the reference system shuttle-based space transportation system to devoted considerable effort to the process perhaps five times the capability (i.e., total of winnowing out a host of alternative ap- mass to space in a given time as represented by proaches. Nevertheless, several other construc- payload size, launch rate, and turn-around) of tion/assembly schemes have been proposed for the present shuttle.57 various phases of SPS program development. The need to conduct relatively sizable ex- If feasible, they would mostly serve the pur- periments, and possibly prototype or demon- pose of reducing costs by using technology stration projects in geostationary orbits rather developed for other programs or by reconfigur- than in low-Earth orbits, would pose a serious ing the reference system scenario. Because transportation problem. Current space-shuttle transportation costs are a significant percent- upper stages, or “orbital transfer vehicles, ” are age of any systems cost (see section on costs not capable of carrying large payloads to geo- below), it would be important to explore these stationary orbit and are not able to support alternatives fulIy. any servicing operations there, since these units are not reusable. Transportation Several innovative approaches have been Transportation strategy in the early develop- suggested that circumvent the need for devel- ment phase and engineering verification is to oping new vehicles. One such approach em- use the shuttle or an upgraded shuttIe to their ploy; an in-orbit propel ant processing facility maximum capacities. In these, as well as later demonstration and production phases, using ‘7 Salkeld, et al,, op. cit.

83-316 0 - 81 - 7 90 ● Solar Power Satellites

built into one of the shuttle’s big “throwaway” sion. This concept is far more ambitious than propellant tanks to convert water into hydro- the in-space propellant processing scheme; fur- gen and oxygen –the best propellants for high- thermore, it depends on a device that, al- performance rocket engines. The water re- though tested extensively on Earth in experi- quired as the feedstock for this process would mental high-speed trains and in the laboratory, be carried into LEO as an “offload” on every has yet to be demonstrated at the scale and ac- space shuttle flight whose payload is less than celeration levels required by the orbital trans- the maximum shuttle capability. The hydrogen fer application. A modest research effort on and oxygen, after being liquefied and stored in this concept is currently being supported by the propellant processing facility’s tank, are NASA’s Office of Aeronautics and Space Tech- then used as the propellants for a reusable low- nology. thrust “space tug” whose principal component The production phase of the SPS program is also a leftover shuttle propellant tank. The would present a number of opportunities for tug, which replaces the cargo orbital transfer transportation alternatives that could not only vehicle of the reference system, would carry reduce production costs, but could also miti- SPS prototype or demonstration hardware up gate environmental and other impacts. Be- to CEO. Although such a system is rather com- 58 cause of the high proportion of total space seg- pletely defined, considerable technology ad- ment construction costs (both nonrecurring vancement and development would be re- and recurring) taken up by transportation, quired, e.g., for the in-orbit electrolysis and many of the proposed innovations center on liquefaction plants, the space-tug-develop- alternatives to the family of four transporta- ment, and the system logistics and integration. tion vehicles selected for the reference system. Cost estimates have not yet been released. Nevertheless, this concept represents an in- The most direct approach to transportation teresting suggestion for eliminating the de- cost reduction would be to improve the HLLV, velopment of a major new (or upgraded) since it absorbs the bulk of transportation launch vehicle just for an SPS demonstration, development and operations costs. The most thereby reducing the “up-front” costs of any likely technological alternative appears to be sizable SPS prototype or demonstration proj- the use of fully reusable single-stage-to-orbit ect. (SSTO) vehicles. 62 Very advanced winged SSTO vehicles that could reduce LEO payload Another scheme would use an electro- 59 delivery costs to the order of $1 5/km are pro- magnetic propulsion device called a “mass jected as becoming practical in the last decade driver” to provide orbital transfer thrust in- of this century, provided sufficient demand stead of the chemical-rocket-powered space exists. 63 tug. The mass driver is simply a solar-powered linear electric motor, which derives its thrust For orbital transfer the personnel and cargo by accelerating chunks of waste mass (e.g., orbital transfer vehicles selected for the chopped-up or powdered shuttle propellant reference system probably represent the best tanks) into space at high exhaust velocities. 60 61 available technology in the two principal op- Since it uses electricity, its energy could come tions: chemical and electric propulsion. directly from the Sun via photoelectric conver- Alternatives for routine high-mass payload 58 Central Dynamics Corp (Convair Dlvlslon), “Utilization of hauling might include solar sails, laser propul- Shuttle External Tank in Space, ” unpublished presentation, j une sion, and various forms of electric propulsion 1978. 5~F, Chiiton, B, H ibbs, H. Kolm, G K O’Neill, and J. phil lips, other than the ion (electrostatic) rocket de- “Electromagnetic Mass Drivers,” in “Space-Based Manufactur- scribed for the reference system, e.g., elec- ing From Nonterrestrial Material s,” G K C)’Neil I (cd.), Progress in Astronautics and Aeronautics, vol. 57 (New York AlAA, August 62 Beverly Z. Henry and Charles H Eldred, “Advanced Technol- 1977), pp. 37-61. ogy and Future Earth-Orbit Transportation System s,” in Space bochllton, et a]., “Mass-Driver Application s,” ibid , PP. 63-94. Manu(actur;ng Facilities //, jerry Grey (ed ) (New York: Al AA, “Gerard K O’Neill, “The Low (Profile) Road to Space Manu- Sept 1, 1977), pp 43-51 facturing,” Astronautics & Aeronautics, March 1978, pp. 24-32. “lbld Ch. 5—Alternative Systems for SPS ● 91

tromagnetic (plasma) thrusters or the mass teroidal materials could be even more favor- driver discussed above. None of these options able. The primary drawback is the high “up- has been studied in enough detail to make front” cost of establishing the necessary min- choices about them at the present time. ing base on the Moon and the space-based facility needed to construct and assemble the Space Construction SPS. Hence, it is not likely that nonterrestrial materials would be used in the prototype, As currently designed, the space component demonstration, or even the early phases of SPS of the reference system would be constructed production. However, if a commitment is in CEO. However, it may be more cost effec- made to produce a large-scale SPS system in tive to build the necessary facilities and CEO, the lunar materials supply option could satellites in LEO and transport them to CEO well be less expensive than the Earth-launched fully constructed. Such a scenario would re- option (including payback of the initial invest- duce the number of personnel needed in CEO merit) . 64 It has been argued that by “bootstrap- as well as lower the total mass that must be ping” the operation (i. e., using nonterrestrial transported there. material right from the beginning, not only to Introducing one of the LEO scenarios (i. e., build the SPS but to build all the necessary laser or mirrors) would open up significant facilities as well), there is no need for any new changes in the construction and transportation launch-vehicle development (a major element option for the SPS. Even a change in one major in the “up-front” investment); i.e., the present component of the reference system satellite space shuttle can provide all the Earth-launch space transportation needed to implement an could alter the ways in which the transporta- 65 tion and construction components are con- operational multi-SPS network. figured. For example, if the photovoltaic cells Decisions on the nonterrestrial materials op- were to be replaced by solar thermal conver- tion clearly hinge on the results of current and sion systems, it would be attractive to con- projected SPS technology studies and experi- struct satellites in LEO and transport them to ments. Sufficient research on the two techno- CEO on their own power because they would logical factors unique to nonterrestrial materi- suffer less from passage through the Van Allen als development—the mass driver (both for radiation belts. lunar materials transfer and for in-space pro- Of all the alternative options for SPS con- pulsion) and lunar materials mining and proc- —should be done so that a struction in the production phase, the prospec- essing capability tive use of nonterrestrial materials is perhaps decision to proceed with either the Earth or the most innovative and, ultimately, capable nonterrestrial materials options could be prop- of the maximum potential return on invest- erly made. Other study and research requirement. ments for the nonterrestrial materials option include system analyses (including design of The basic premise of the nonterrestrial ma- an SPS that maximizes the use of lunar materi- terials option is that the cost, energy and mate- als), more intensive searches for appropriate rials requirements, and environmental impact Earth-approaching asteroids, and establishing of lifting the enormous cumulative masses capabilities for the host of space operational needed to establish and operate a system of functions needed for other space programs. many satellite power stations off the Earth can be markedly reduced by utilizing first lunar As is clear from the preceding discussion, it materials, and eventually materials obtained is difficult to establish a priori alternatives to from asteroids. The fundamental physical prin- construction, assembly, and transportation, ciple that supports this premise is that it takes over 20 times as much energy to launch an ob- “Davld L Akin, “Optimization of Space Manufacturing Sys- terns, ” in Space Manufacturing ///, Jerry Grey and Christine Krop ject to geostationary orbit from the Earth as it (eds ) (New York. AlAA, November 1979) does from the Moon, and the situation for as- b50’Nelll, op cit 92 . Solar Power Satellites

since each of the SPS alternative options essentially developed space shuttle; 3) max- would call for a different approach. General imizing the common utilization of technology guidelines can be identified, minimizing and development efforts by other programs transportation and construction costs during having related requirements (e.g., large com- the evaluation, development, prototype, and munications antennas and other large space demonstration phases by: 1) utilizing a phased, structures, spacecraft power generation, con- step-by-step approach (e. g., ground-based ex- trol and transmission, etc.); and 4) developing periments, only then followed by dedicated new transportation vehicles and construction space experiments); 2) maximizing use of the hardware only when economically necessary.

SPS COSTS

Although knowledge of the overall costs of Figure 23.—Reference System Costs a an SPS program will be essential to making a (dollars in billions) decision about developing the SPS, current cost estimates are inadequate. Today’s projections are based on extrapolations from current technology and in most cases assume major advances. Thus, the technical uncertainties of the concept are too great to provide a firm basis for economic analyses. Here, as in most other areas, it is only possible to develop the foundation for future analysis that would seek to reduce the current uncertainties.

Reference System Costs

The most detailed cost estimates have been made by NASA66 for the reference system (fig. 23). According to these estimates, which are based on detailed hardware specifications and associated transportation and industrial in- f restructure, achieving the first complete reference system satellite will require an investment of $102.4 billion over a 20-year period. Figure 24 illustrates one estimate67 of how the costs could be allocated over time. Each additional copy of the satellite and associated terrestrial facilities would cost $11.3 billion. Expenses are divided into the following phases:

● Research — $370 million. This phase of SPS development (table 10) is by far the small- est, constituting less than 0.4 percent of the total SPS program. About half of these

bbPiland, op. cit. “Woodcock, “Solar Power Satellite System Definition Study,” aNASA estimates—1977 dollars. op. cit. SOURCE: National Aeronautics and Space Administration Ch. 5—Alternative Systems for SPS ● 93

Figure 24.— How Cost Could Be Allocated Table 11 .—Engineering—$8 Billion — Millions Percent of dollars of total SPS...... $ 370 5 Test article hardware ...... 210 3 LEO base (8 man) ...... 2,400 30 Manned orbital transfer vehicle. . . 1,200 15 Shuttle flights...... 870 11 Shuttle booster...... 2,900 36 Management and integration . . . . 61 1 Total...... $8,000

NOTE: Percentages do not total 100% due to rounding errors. SOURCE: National Aeronautics and Space Administration.

Table 12.—Demonstration—$23 Billion

Millions Percent o of dollars of total Years Demonstrator: DDT&E ...... $2,700 12 SOURCE: National Aeronautics and Space Administration. Hardware...... 2,500 11 Pilot production facilities ...... 400 2 Shuttle DDT&E and fleet ...... 3,000 13 Construction: Table 10.—Research—$37O Million DDT&E ...... 3,100 13 Hardware...... 3,000 13 Millions Percent Space operations (4 years of dollars of total operations, construct bases, and demonstrations) ...... Power generation ...... $ 79 21 2,800 12 Personnel orbital transfer vehicle Power transmission ...... 40 11 (DDT&E and hardware)...... 1,700 Structures and control...... 22 6 7 Electric orbital transfer vehicle Space construction ...... 25 7 (DDT&E) ...... 1,800 Space transportation ...... 20 5 8 Demonstration rectenna ...... System studies...... 19 5 1,800 8 Management and integration . . . . 200 Research flight test ...... 165 45 1 $370 Total...... $23,000 SOURCE: National Aeronautics and Space Administration. SOURCE: National Aeronautics and Space Administration.

costs are chargeable to the development ciated rectenna and ground facilities to of the transportation system. collect and disperse electrical power to ● Engineering–$8 billion. This part of the the grid. The demonstrator requires a sec- program (table 11) contributes the com- ond generation shuttle and orbital trans- plex engineering knowledge necessary for fer vehicle to provide the transportation creating a useful space structure. The capabiIity to GEO. work includes developing an engineering ● Investment—$57.9 billion. By far the test article in LEO, capable of generating largest percentage (57 percent) of the non- 1 MW of power. It is the direct precursor recurring costs of the reference system are to the demonstrator and provides the test- devoted to this phase (table 13). In addi- ing ground for constructing and using col- tion to providing for the transportation lector and transmitting subarrays, a rotary and construction capabilities for the joint and satellite attitude control. space component, it also includes the ● Demonstration –$23 billion. This phase of costs ($7.8 bill ion) for developing the ter- the reference program (table 12) culmi- restrial factories needed to produce satel- nates in a 300-MW satellite and the asso- lite components. 94 ● Solar Power Satellites

Table 13.—SPS lnvestment—$57.9 Billion alone vary by a factor of 30 ($40 to $1 ,250/kg). Millions of Percent ● dollars of total Photovoltaic cells. GaAs cell cost esti- Heavy lift launch vehicle ...... $16,600 29 mates are extremely optimistic given the Development...... $10,500 18% current state of technology. Break- 0 Fleet (6 boosters, 7 orbiters) ... $ 6,100 11 /0 throughs will be needed to reach the Electric orbital transfer Vehicle (21 x 284)...... 6,000 design goals for mass, efficiency, and Construction bases ...... 17,200 30 costs. Silicon cell cost estimates are less Development...... $ 4,300 8% optimistic but will still require significant Hardware and launch ...... $12,900 22%. SPS development ...... 2,200 4 simultaneous reductions in mass and cost Ground-based factories and an increase in efficiency to achieve (klystrons, solar cells, etc.) . . . . . 7,800 13 the SPS goal (2 g/W, $0.17/Wp, and 17- Launch and recovery sites...... 7,300 13 Program management and percent efficiency). integration...... 800 1 ● Slip ring. It is not well enough defined to Total...... $57,900 appraise the slip ring components or their

SOURCE: National Aeronautics and Space Administration. operational capabiIity. ● Satellite electrical systems. The degree of detail is insufficient to judge the credibili- Though these are the best estimates currently ty of the cost estimates of the subsystem. available, they suffer from an unavoidable lack of specific engineering details, as well as Thus, the $102.4 billion estimate of “front from insufficient manufacturing experience end” costs and the $11.3 billion estimates for for most of the system components. Moreover, each satellite may be an optimistic estimate of in some areas, (e. g., klystrons, slip ring, phase SPS costs. control) current technology is inadequate to On the other hand, if unexpected break- define solutions to engineering problems. throughs were to occur in space transporta- Thus, the estimates could eventually turn out 68 tion, rectenna or satellite technology, the costs to be high or low. The DOE SPS Cost Review of the reference system could be lower than examined five different elements of the SPS now estimated. Since NASA estimates already reference design and concluded that the pro- assume some technological breakthroughs jected costs are “based on optimistic assess- (e.g., in solar cell production, space construc- ments of future technological and manufac- tion, rectenna construction), they are more turing capabilities. ” likely to be low than high. In either case, the ● Rectenna support construction. Projected estimates reflect a troublesome feature of the costs were found to be low by a factor of reference system —the high costs that are nec- 3 to 5. Automated production might essary to demonstrate the feasibility of the SPS reduce costs to a level more in keeping (about $31 billion). A further $71 billion would with the reference system estimates, but be needed to build and use a single reference significant advances over today’s meth- system satellite (investment of $57.9 billion ods would be needed. and a first satellite costing $13.1 billion). ● Graphite fiber-reinforced thermoplastic. Because the initial costs have a direct bearing Currently used for golf clubs, fishing rods, on financing the project, they are more fully and for any other use where low weight discussed in chapter 9. and high stiffness are required, this is the A number of opportunities exist for reducing recommended material for the satellite SPS development expenses. Some involve pur- truss work. The proposed structures are suing alternative concepts; others, revising the insufficiently defined to specify the costs. reference system. Because the reference sys- Estimates of future costs for the materials tem is by no means an optimal design, improvements could lead to significant cost ‘*J. H. Crowley and E J. Ziegler, “Satellite Power Sy5tems (SPS) Cost Review,” DOE/TIC-11190, MaV 1980 reductions. Common to all potential systems Ch. 5—Alternative Systems for SPS ● 95

would be the division of SPS development into private investment in space is strong for other the phases outlined above: research, engineer- reasons. Under these combined circumstances, ing verification, demonstration, and invest- the total risk to the U.S. taxpayer would be ment, with increasing commitment of re- substantialIy reduced. sources in each successive phase. For micro- One interesting option for reducing trans- wave and laser systems, space transportation portation costs of a CEO SPS would be to and construction would constitute a high per- assemble the satellite in LEO and send it to centage of the system costs in all phases. It is CEO under its own power. This might be in these areas that there would be a high particularly applicable to the demonstration potential for reducing overall costs. phase of the reference program, since it would The precise costs of an SPS program would avoid the need for premature investment in an also depend strongly on the nature and scope expensive manned geosynchronous construc- of national and global interest in space. If tion/assembly facility. commercial ventures in space grow at a strong Whatever their potential savings, all of these enough rate (e. g., for telecommunications sat- possibilities could only be evaluated after the ellites, space manufacturing, etc.), the current proper scale of a demonstration satellite had shuttle and its related technology would be in- been determined. This decision, in turn, would adequate, and pressures would be strong for depend on considerable terrestrial and space- developing expanded space capabilities. The based testing, some of which will take place in explosive growth of the domestic airline in- other space programs (see ch. 5). dustry since the 1930’s has been suggested as the appropriate model to use to investigate Because the HLLV would be used later on in this eventuality. 69 the production phase of the reference SPS absorbs the bulk of transportation costs, it is of Much of the technology and experience considerable interest to find less expensive needed for space construction (manned LEO ways of transporting mass to space. Some of and GEO bases, large-scale antennas, studies the alternative high-capacity transportation of space productivity, etc. ) and space transpor- vehicles have been discussed earlier in this tation (manned and unmanned orbital-transfer chapter. The heavy Iift launch vehicles achieve vehicles, shuttIe boosters, HLLVS, etc.) of SPS their cost reductions by economies of scale. It would be developed for other programs as has been suggested that smaller vehicles, well. Of these, the SPS program should bear perhaps only slightly larger than the current only its share. By charging only those costs space shuttle, could be used instead of the that are unique to SPS to the SPS program, its 71 much larger HLLV. The smaller vehicles front end costs would be reduced by a signifi- would use higher launch frequencies to cant amount. Seen in this light, the massive achieve the same or better benefits. According space capability needed for mounting an SPS to this proposal, the minimum-cost individual program would be less of an anomaly (given payload necessary to launch as many as five the future evolution of space technology), ’” reference SPS satellites to orbit is about 50 and SPS would need to shoulder fewer of the tonnes (compared to the Shuttle’s 30 tonnes). development costs for this capability. The prospects for employing routine airline- There is also the possibility that a percent- Iike launch practices opens a whole new ap- age of the investment phase could be shoul- proach to the logistics of major space manu- dered by private investment, thereby reducing facturing enterprises as well as providing the burden to taxpayers. This would be all the potential cost reductions for SPS. more likely to happen in a milieu in which

“C, R. Woodcock, “Solar Power Satellites and the Evolution of Space Technology, “ AIAA Annual Meeting, May 1980. “R. H Miller and D. L. Akin, “Logistics Costs of Solar Power 701 bid. Satellites,” Space So/ar Power Review, VOI 1, pp. 191-208,1980. 96 ● Solar Power Satellites

ALTERNATIVE SYSTEMS

Systems other than the reference system The Laser System might be more or less costly, depending on factors such as the achievable efficiency, the The largest unknowns for the laser system mass in orbit, and the state of development of are the efficiency, specific mass and the cost the alternative technologies that make up of the transmitting lasers themselves. This is these systems. At present, these alternatives because the technology of high-power CW are much less defined and their costs accord- lasers is in a relatively primitive state (current ingly even more uncertain than the reference CW lasers achieve outputs of 20 kw or greater, system costs. The following discussion summa- operated in a so-called loop move, i.e., the rizes available cost data and the greatest cost Iasant is recirculated). Space lasers for SPS uncertainties of the alternative systems. would have to operate at much higher outputs (megawatts) and at higher efficiencies (i.e., 50 The Solid-State System v. 20 percent) for current lasers. Concepts such as the solar pumped laser and the free electron ● The unit cost of the solid-state devices is un- laser are completely untried in a form that known. However, the semiconductor indus- would be appropriate to SPS. Therefore their try has considerable experience in producing costs are even more difficult to ascertain. In large numbers of reliable solid-state com- general it can be said that the cost of the ponents at low cost, and the learning curve system would be tied to the overall efficiency for such production is well-known. In princi- of the system and the amount of mass in ple, it should be possible to make a realistic space, but considerable study and some devel- prediction of costs when the appropriate de- opment would be needed to make suitably vice or devices are well characterized. reliable projections. ● Solid-state efficiencies. Present efficiencies ● Transportation. The laser systems that have are much lower than for the klystron. Cur- been explored project higher mass in orbit rent research is aimed at increasing their than for the reference system, which may operating efficiency (to reach at least 85 per- drive the cost of the laser system up. How- cent). ever, if a substantial portion of this mass is ● Mass in space. Current estimates of the mass in LEO rather than in CEO, the overall trans- per kilowatt of delivered power72 suggest portation costs might not exceed the trans- that the mass in space would be higher than portation costs of the reference system and that of the reference system making the could turn out to be lower. transportation costs higher as well. ● Demonstration. Because the laser system is Since many components of the solid-state intrinsically smaller it should be possible to system are shared with the reference system mount a demonstration project for consid- (e.g., the graphite fiber reinforced thermo- erably less than for the reference system. plastic support structures, the photovoltaic arrays, the rectenna design, etc.), it would be ● Terrestrial component. The ground stations possible to generate realistic relative costs if would have to have a certain amount of re- the above uncertainties are reduced. dundancy in order to accommodate laser transmission when cloudy weather obscures one or more receivers. The precise amount of redundancy would depend on the particular location and would include extra trans- 7*G. Hanley, “Satellite Power Systems (SPS) Concept Defini- tion Study,” vol. 1, Rockwell International SSD-8O-O1O8-I, Oc- mission lines as well as extra ground tober 1980. receivers.

Ch. 5—Alternative Systems for SPS ● 97

The Mirror System ducing the same overall output computed on identical assumptions would cost 115 Figure 25 summarizes mirror system cost m i I Is/k Wehr. estimates for the SOLARES baseline case73 based on the DOE 1986 cost goals for photo- Since electricity production from the mirror voltaic cells. These “up front” cost estimates, system would depend heavily on the use of ter- which include contingency and interest on the restrial solar photovoltaic or solar thermal borrowed money, lead to an estimated level- systems, cost variations of either conversion ized busbar energy cost of 31 mills/kWehr system would have a strong effect on total compared to 1990 estimated costs of nuclear/ system costs. Figure 26 summarizes the effect coal mix of 45 mills/kWehr. I n comparison, a of varying several system parameters on the strictly terrestrial system of photovoltaics pro- cost of electricity delivered to the busbar in the SOLARES system. The three most sensitive 73 et “Solar Energy Economics Revisited: The Promise and Challenge of orbiting Reflector for World Energy parameters are solar cell efficiency, solar cell Supply, ” cit. cost per peak kilowatt and total space cost

Figure 25.—Elements and Costs, in 1977 Dollars, for the Baseline (photovoltaic conversion, 4,146 km, inclined orbit) SOLARES System

Solar cells

NOTE: Total costs are proportional to the areas of the circles. Interest and contingency constitute 33 percent of the total SOLARES costs. SOURCE: K. W. Billman, W. P. Gilbreath, and S. W. Bowen, “Space Reflector Technology and Its System Implications” AlAA paper 79-0545, AIAA 15th Annual Meeting and Technical Display, 1979.

98 ● Solar Power Satellites

Figure 26.—Sensitivity of the SOLARES Mirror (transport, construction, mirrors in space). A System to Variations in System Parameters cost over-run of about 2 times (to $1,000/pk kWe) could be tolerated before a busbar cost of 45 milis/kWehr wouId be reached. Similarly, a space system total cost over-run of a factor of 4.25 could be tolerated. Finally, because of the projected high energy production per unit of mirror mass in space, a twenty-three-fold increase in space transport cost (or $1 ,380/kg) would still result in a production cost of 45 mills/kWehr. For comparison, the charge for transporting mass to space by means of the space shuttle is estimated to be between $84 and $154 (1975 dollars). ”

74 National Aeronautics and Space Administration, “Space Transportation Reimbursement Guide,” JSC-11-802, May 1980 % Variation of parameters

SOURCE: Ken Billman, W. P. Gilbreath, and S. W. Bower, “Space Reflector Technology and Its System Implications” AlAA paper 79-0545 AlAA 15th Annual Meeting and Technical Display, 1979, Chapter 6 SPS IN CONTEXT Contents

Page Table No. Page Energy...... 101 16. Description of Milestones of Major Introduction ...... 101 Breeder Programs ...... 116 Overview ...... ,101 17. Summary Assessment...... ,.125 Determinants of Demand...... 102 18. Major Environmental Risks...... 127 Energy Supply Comparisons ...... 104 19. Terrestrial and Space Insolation Implications...... 131 Compared...... 128 20. Terrestrial Insolation at Different The Effects of SPS on Civilian Space Latitudes and Climates ...... 129 Poilcy and Programs ...... 135 21. Costs of Onsite Photovltaics...... 131 Space Policy...... 135 22. Range of Energy Demand in 2030,....132 Current and Projected Space Projects. . .137 23. Upper Range of SPS Use . ..,...... 135 Institutional Structures...... 139 indirect Effects and ’’Spinoffs”...... 139

LIST OF FIGURES LIST OF TABLES Figure No. Page Table No. Page 27 Recent and Projected Solar 14. Criteria for Choice, , ...... 105 Photovoitaic Prices. ., . . . + ...... 114 15. Characteristics of Five Electrical 28 Levelized Lifecyle Cost of Electricity ..124 Technologies...... 110 29 Quarttified Health Effects...... 126 Chapter 6 SPS IN CONTEXT

ENERGY

Introduction problems that would result from potential supply interruptions and to improve the U.S. trade Because of its long development Ieadtime, deficit. To do this, concentration must be solar power satellites (SPS) will not be avail- placed on lowering demand growth by increas- able to any extent before the early part of the ing the efficiency of energy use, and switching next century and will therefore do very little to to the use of more abundant domestic fuels. relieve our dependence on imported oil. SPS’s Of the two, improving energy efficiency will be primary use would be to replace old power- the major new source of energy because of the plants and meet any new demand for elec- much longer Ieadtime needed to bring on new tricity. Consequently, the potential value of fuel supplies such as coal and nuclear. Do- the SPS must be determined in competition mestic oil and natural gas can be developed with other future electricity sources and in the more quickly, but it is not likely that they will context of U.S. and global electricity demand. contribute to reducing oil imports since both This chapter examines this topic in detail by will probably decline in production for the looking at the future demand for energy, and decade. A recent OTA technical memoran- electric power in particular, in the United dum’ estimates a 25-to 45-percent drop in U.S. States, and the various supply options that oil production by 1990. Thte use of nuclear could compete with the SPS. Global energy de- energy will increase, but at a slower rate than mand and the SPS in a worldwide context is ex- in the 1970’s. Finally, solar and biomass energy amined in chapter 7. production will grow rapidly during the 1980’s but the absolute magnitude will be low com- Overview pared to oil imports. Therefore, although an increase in the amount of coal, solar, biomass, The U.S. energy future can be divided into and possibly nuclear energy sources is ex- three time periods according to the supply op- pected, they will probably not be able to con- tions that will be available. These periods are tribute enough by themselves to relieve the roughly the next 10 years (near term), from pressures caused by U.S. dependence on im- 1990 to approximately 2020 (the midterm or ports. transition period), and beyond 2020 (the long term). Although these boundaries are not hard Transition Period: Midterm and fast, they roughly define periods in which In the period from 1990 to 2020, substantial particular energy supply forms will dominate. supply shifts will occur. Although the period will begin with heavy dependence on coal, oil, Near Term and natural gas, it will end with a much greater In the near term, there will be no significant reliance on renewable and inexhaustible ener- change from our current reliance on oil, natu- gy resources. U.S. dependence on imported oil ral gas, and coal. Currently about 92 percent of will almost surely come to an end if for no our Nation’s energy supply comes from these other reason than that the availability of oil on fuels. About one-quarter of the total is im- the world market will have dropped substan- ported (almost all in the form of oil). Because tially. World oil production may drop as much of finite suppIies, overalI consumption of these as 20 percent by 2000 and fall off sharply liquid and gaseous fossil fuels must eventually thereafter. The dominant fuels during this be reduced. However, the most important goal ‘Office of Technology Assessment, U.S. Congress, “World over the next decade is the reduction of oil im- Petroleum Availability, 1980-2000,” technical memorandum, Oc- ports in order to avoid the severe economic tober 1980, OTA-T M-E-5

101 102 ● Solar Power Satellites

period are likely to be coal (for synthetic fuels, Determinants of Demand direct combustion, and electricity generation), natural gas, and possibly conventional nu- SPS would fit most easily into a high electric clear. During this period, strong growth of re- growth future. Such a future is contrary to renewable and inexhaustible sources such as cent low growth trends. In fact, many conser- solar and biomass can be expected. Uranium is vation initiatives have been directed at reduc- a small enough resource that conventional ing the use of electricity because of the high nuclear must be considered a transition energy energy losses at powerplants. Nevertheless, source. However, the supply of coal appears to changes in relative fuel prices and gains in the be substantial enough to play a major role well efficiency of electric generation and use could into the 22d century. Whether these fuels con- dramatically change the picture. tribute significantly beyond the midterm de- The energy technology choices the United pends on the successful resolution of their States and the world will make in moving short- and long-term environmental and safety through the three periods described above will questions. be primarily dictated, as always, by relative costs. Until recently the dominant factor deter- It is also during this period that SPS and mining the development of energy tech- other long-term candidates such as breeder re- nologies has been the type of resource and its actors and perhaps fusion may begin to reach availability. The abundance of oil and natural commercial status. The transition period will gas, and the ease with which it could be be the time when a number of long-term tech- transported and burned, dictated the de- nologies will compete with one another for a velopment of most of the energy-using equip- role in the future on the basis of economics ment currently in existence. Some of this and public acceptance. This competition will equipment could have been powered more ef- also depend heavily on the relative economic ficiently by electricity, but this advantage was efficiency of different ways of using energy, as often dwarfed by the cost advantage these will be discussed below. fuels had over electricity. However, many applications such as electric motors can be made Long Term significantly more efficient, reducing the fixed In the long term, the United States and the cost penalty. world will be almost totally fueled by in- In the past few years the relative prices of exhaustible energy sources. Although rapid these energy forms have changed because of growth of sources such as the SPS during the the rapid increase in oil and natural gas prices. first decades of the century may be seen, it will Current average electricity prices are about not be until the middle of the next century that twice that of oil and four times that of natural they could become as commonplace as coal, gas. In 1960, the ratio of electricity to oil and electric, or even nuclear plants are today. natural gas prices was 7 to 1. Even though the costs of new powerplants are rising rapidly, It is not clear which renewable and in- those of electricity will probably rise more exhaustible sources will dominate. It may be slowly than oil and natural gas, primarily that small-scale, onsite solar systems coupled because of the relative abundance of coal and with an extremely energy-efficient economy uranium. It is even possible that synthetic fuels will be the ultimate future. It may also be that from coal and biomass may be more expensive a mix of technologies such as onsite solar, than electricity from coal, particularly as biomass, fusion and/or SPS will be used. newer, more efficient coal combustion tech- However, the choice will be made in the transi- nologies are introduced. tion period and will be based primarily on the projected costs of competing supply systems The total cost to the energy user also in- and demand technologies. cludes the cost of the energy consuming equip- Ch. 6—SPS in Context ● 103

ment. Electric powered equipment is often through the use of motors. Electricity is also cheaper than gas or oil fired counter parts. used for industrial electrochemical processes This advantage will become increasingly im- such as in aluminum and steel production, for portant as the prices of oil and gas narrow the specialized induction-heating applications and gap with the price of electricity. for microwave and infrared furnaces. A small but crucial amount is used to power the Na- The implication of these effects is that election’s electronic systems. Finally, electricity is tricity may become the cheapest energy form, used in the crudest form possible, namely for when both supply and demand are considered, direct conversion to heat. for many applications that could use a multi- plicity of energy forms. The reason is that the Although these uses are more varied than for price differential between electricity and the the other major fuels, they account for less other energy forms (liquid and gaseous fuels, than 12 percent of the total end-use energy de- direct solar, etc.) will likely be small enough mand in this country. The other 88 plus percent that it could be overcome by cheaper and is direct combustion to provide direct heat, more efficient electric end-use technologies. steam and mechanical drive. As indicated, for Some of these, such as heat pumps for space electricity to penetrate this latter market it will and water heating, are already in use, while be necessary to make technical advances to others, such as inexpensive electrochemical give electricity a cost advantage at the end-use processes and long-life storage batteries, re- that can compensate for its higher cost at the quire further development, [f such develop- production point. ment is successful and electricity does become To do this requires making use of the special the cheapest energy form for most uses, then character of electricity as an energy form. electric demand growth could become quite Electricity is a high-quality fuel (thermo- rapid even though total energy demand may dynamically work that is heat at infinite tem- grow very slowly or not at all. perature). Therefore, it can be used for any If this holds, solar power satellites will have kind of mechanical work or it can be con- an easier market to penetrate than if the elec- verted to heat at any temperature. The best tric utilities continue their recent slow growth. known example of the latter property is the Thus, the fate of SPS rests as much on the abili- heat pump for space heating. This is now being ty to create energy efficient electrical end-use applied to water heating and certain drying ap- technologies as it does on the relative eco- plications with a substantial reduction in

nomics of other electric generating technol- energy use over electric resistance heating and ogies. One caveat must be added, however. If apparent cost advantages over solar. demand technologies for fuels keep pace with In the industrial area, there is considerable the efficiency improvements of electric de- potential for increased use of electricity. For mand technologies, such dramatic switchin g instance, in steel making it can be used for the may not occur. plasma-arc process and direct-electrolytic reduction of iron. Although these processes have Electric Demand Technologies been arourd for several years, technical de- To see if such a future is technically possible velopment is still needed. In a nearer term ap- a closer look is taken at current and potential plication, the direct reheating of steel by high, uses of electricity. Because of electricity’s pulsed electric currents could result in a sig- unique properties it has been used for nificant reduction in fuel use compared to specialized tasks such as lighting because of direct-fired processes, and also reduce mate- the high temperature needed to excite the visi- rial loss by eliminating oxide formation that ble spectrum. Here, electrical energy is con- occurs with direct firing. In other areas ad- verted to visible electromagnetic radiation as vances have been seen recently in the efficien- well as to heat. Nearly 60 percent of all elec- cy of electric motors that are now competitive tricity is used to perform mechanical work with steam drives in many applications such as 104 Ž Solar Power Satellites

mechanical presses for metal forging. A more Conclusion speculative but very interesting area is the use It is likely that as technologies using elec- of laser or microwave radiation to drive in- tricity are improved or new efficient uses are dustrial chemical reactions, instead of heat. found, improvements will be made in using other future nonelectric energy sources such In ground transportation the principal prob- as biomass and direct solar. While all of these lem is the development of long-lived, light- developments are many years away, it is this weight, reliable storage batteries. EIectric environment in which the SPS will compete. drive using motors with precise solid-state The success or failure of these new electric speed control can be made very efficient, as has been demonstrated on many of the world’s technologies will have a great deal to do with determining whether or not a market exists for railroads. Advances have recently been made in battery technology but the general feeling is SPS as well as the other large-scale, electric- generating technologies. that “ideal” batteries are at least a decade away. Energy Supply Comparisons The industrial sector is presently only 13- Introduction percent electrified, while the transportation sector only uses a negligible amount of elec- Comparisons with other energy technol- tricity. Thus, these are the markets that elec- ogies, both current and future, are a critical tricity must penetrate to become the dominant part of assessing a proposed new energy tech- energy form. However, some new technologies nology. A host of criteria, only some of which have the potential to reduce industrial de- are readily quantifiable, is available for com- mands without creating new markets for elec- parison purposes. Costs, environmental im- tricity. In the chemical industry, for instance, pacts, scale, complexity, versatility, safety, biogenetic methods of feedstock synthesis and health risks are some of the more impor- could replace thermochemical methods, re- tant factors of choice that ultimately deter- ducing fuel usage without substituting elec- mine the relative desirability of a given energy tricity. About half the present industrial elec- technology. For technologies currently in tric demand could be offset by cogeneration, a place these factors are generally well known. technology that is not strictly a demand tech- For future technologies they are more often nology but which could nevertheless reduce only poorly known. Nevertheless, choices electricity needed from the grid. I n the trans- among future energy technologies must be portation sector, battery research as a key to made, either in the R&D phase, or, later, in the electric vehicles must compete with the effi- marketplace. ciency improvements possible with high- mileage advanced vehicles using synthetic or Criteria for Choice biomass-derived liquid fuels. The buildings Whenever decisions to proceed with or halt sector is already the most heavily electrified the development of a given technology are and some electric technologies, such as com- made, it is important to lay out the framework mon appliances, are nearing saturation. of choice, to develop a set of criteria by which one may judge the relative benefits and draw- The achievement of highly efficient, electric backs of different technologies. In addition to demand technologies would change not only providing a basis for choice, such a list can the balance of fuels now used but also the sec- also help to identify the essential distinctions toral usage patterns of electricity, with between technologies and highlight areas that dramatic growth in the industrial and transpor- will need further R&D. tation sectors, and less in the buildings sector which has shown the greatest postwar growth Table 14 lists 32 criteria developed in an in electric demand. OTA workshop that are often used in compar- Ch. 6—SPS in Context ● 105

Table 14.—Criteria for Choice solar thermal technologies, terrestrial solar photovoltaics, advanced fission (the breeder), Plant description 1. Scale of power output (range in megawatts) and fusion. If the health and safety problems 2. Power output in relation to load profile (baseload, of coal are satisfactorily solved, it could also intermediate, peaking) be a major electric supply technology in the 3. Versatility (other output besides electricity) 4. Complexity (high, medium, low) and maintenance period that SPS could become available. In ad- requirements (controllability) dition, there may also be a component of con- 5. Reliability (percent of time available to the grid) ventional nuclear power still operating in the 6. Nominal capacity factor (percent time operating) 7. Material requirements second and third decades of the 21st century 8. Labor requirements (the timeframe after 2010 that is most likely for 9. Land requirements SPS deployment). 10. Construction Ieadtime (years) 11. Lifetime (what are key determinants) The data that OTA generated for these tech- costs nologies are supplemented by the electrical 12. Opportunity costs of RD&D (dollars and people) 13. Net energy ratio supply comparisons which Argonne National 14. Operating costs (cents/kWh) Laboratory made for the Department of 15. Capital costs ($/kW) Energy (DOE/SPS) assessment program.3 DOE 16. T&D costs (cents/kWh) 17. “Decommissioning” costs chose to study conventional and advanced Impacts coal technologies, light water reactors, liquid 18. Institutional (organization and ownership) impacts metal fast breeder reactor (LMFBR) breeders 19. Safety and health risks (magnitude and distribution) fusion, the reference system SPS, and ter- 20. Environmental risks (magnitude and distribution) 21. National security risks of normal or unintended use restrial photovoltaics operating in a peaking 22. Military vulnerability mode. Their data will be discussed along with Deployment consideration the results that OTA obtained. Coal and con- 23. Time period to commercialization ventional nuclear power will be presented first 24. Geographic location; location of plant with respect to load centers to provide a reference for the future energy 25. Compatibility with other technologies and utility grid technologies in the discussions that follow. Other 26. Probability for success (high, low, medium) THE COAL BENCHMARK 27. Initial demonstration requirements (large or small) 28. Resource constraints (domestic, international) The coal resources of this country are 29. Risks/impacts of RD&D failure (chance it may become almost incomprehensibly large. Even if pro- prematurely obsolete) 30. Relative uncertainties to be resolved by RD&D (e.g., duction were to triple, in that case coal would sensitivity of efficiency to design parameters) serve about half the present U.S. energy needs, 31. Is it a viable example for rest of world? known recoverable reserves would not be ex- 32. Nature of R&D process (public, private, classified) hausted until late in the next century. Es- SOURCE: Office of Technology Assessment timated additional reserves could take this production well into the 22d century. Thus, for ing electrical generating technologies. Most fit all practical purposes, the supply of coal is in- into four broad categories: plant description, exhaustible. costs, impacts, and deployment considerations. These criteria establish a context for Unlike any other long-term energy source, evaluating the SPS in relation to other future coal can be exploited with known, proven energy technologies. technology at costs that are competitive now. Advanced coal technologies such as com- Five Future Energy Technologies bined-cycle gasifiers and magnetohydrody- In the timeframe that the SPS would be most namics, are not vital to coal’s future but could likely to play a role in the U.S. energy future, the other energy sources that are likely to ‘M E Samsa, “SPS and Alternative Technologies Cost and contribute wilI be predominantly the renew- Performance Evaluations, ” The Final Proceedings of the Solar Power Sate//;te Program I?ev;ew, CON F-800491 (DOE), 1980. able and inexhaustible ones. OTA has chosen ‘Program A$$e$sment Report Statement of F;nd/ngs, SPS Con- to study the SPS in comparison to terrestrial cept and E valuation Program, DO F/E R-0085, 1980

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improve the efficiency and economics of coal- bers, but also because the equipment in use fired electric power. Thus, of all the options has generally shown disappointing reliability. for large-scale, long-term production of elec- However, current systems appear to be consid- tricity, coal is the least uncertain technolog- erably better than early designs, so utilities ically and economically and it is appropriate can, if they are careful, be confident that their to view it as a benchmark for evaluating the equipment will function reliably and effec- others, including SPS. tively.

Technological and economic criteria are not The regulatory approach has been to ensure the only alternatives to consider. Any energy that the impacts are controlled to the point source must have generally acceptable health where it is clear that known damages are and environmental impacts. Coal evokes de- sharply reduced. As mentioned above, it ap- pressing memories of scarred landscapes, suf- pears that this goal has been achieved. As fering miners and smokey skies. Today, this more information is gained, it is possible that reputation is no longer deserved. Modern coal control can be loosened without increasing the mining and combustion techniques, when risk. For instance, new data on the damage properly applied, have reduced virtually all caused by sulfur oxides and sulfates, and bet- these objectionable impacts to the point where ter data on the long range transport and chem- damage is clearly a small fraction of what it ical transformation of these and other pollut- once was. ants might allow more selectivity in emissions The actual future of coal, however, is much control. Thus, the costs of controlling impacts less certain than its potential. Issues arising may be reduced rather than increased in the when expanded mining and use are considered future. Such a reduction would improve coal’s can be divided into three categories: interrup- competitiveness with nuclear power or SPS, tions, control costs, and risks. These will be unless some of the unproven risks are con- discussed in some detail because if coal does firmed. not realize its potential, the reasons will prob- There are three major risks to long-term coal ably be found here. combustion that could limit expansion or Interruptions are intermittent events that make it much more expensive: public health

prevent scheduled plans from being fulfilled. effects, acid rain, and carbon dioxide (C02). Strikes by miners and transportation break- Coal combustion pollutants have been linked downs are obvious examples. Opposition by in- by statistical analyses to tens of thousands of tervenors that prevent facilities from being deaths per year. These studies are highly con- built might be included here. These factors troversial and have been neither proven nor can’t be completely eliminated, but proper disproven. If they are generally accepted, con- planning can reduce disruption. The major siderable reduction of sulfur and nitrogen long-term effect is to deter potential users oxides would probably be necessary. This from turning to coal if they have other options reduction would probably call for greater use and are concerned about the reliability of the of coal cleaning before combustion, combus- coal supply. tion modifications and higher efficiency flue- gas desulfurization systems. Such changes The cost of controlling coal’s negative im- would be expensive but unavoidable if the pacts is high. Reclaiming surface mined lands public demands cleaner air because of con- and reducing the emissions of combustion cerns over health risks. have received the most attention. For instance, the Clean Air Act Amendments of 1977 have The documentation for damage by acid rain required the use of the “best available control is better than for public health effects, but is technology” for limiting emissions of sulfur still not conclusive. Acid rain is evidently oxides. Utilities have been concerned not only caused by the same pollutants suspected in the because of the expense of the flue-gas scrub- public health issue, but the scientific under- Ch. 6—SPS in Context ● 107

standing of pollutant transport and chemical will be required before enough is known to conversion is poor. Furthermore, while acidifi- make intelligent decisions about the signifi-

cation of certain lakes and streams is strongly cance of the effects of increased CO2 in the suspected, extensive damage to terrestrial eco- atmosphere. The contribution of fossil fuel

systems is only surmised. If this damage is combustion to the CO2 buildup, the results of proved and found too costly, the remedy this buildup on the heat balance and climate, would be the same as for public health effects. and the effects of climate changes must all be However, it must be emphasized that proof of studied extensively. At some point, however, it damage is insufficient. The pollutants must be may be necessary to limit coal combustion in

traced back to their source in order to know order to limit CO2 emissions since it is highly where to implement controls. Otherwise inef- unlikely that any practical means of removing

fectual or overly expensive control strategies CO2 from the flue gases will be devised. may be implemented. In summary, as far as we can tell now, coal is The final risk, excessive CO released to the 2 capable of supplying most of the electric atmosphere, is by far the most intractable. The power this country is likely to need for many adverse impacts that have been suggested generations. The effects of the release of extra dwarf those of any other human activities with CO, to the atmosphere are sufficiently in the possible exception of nuclear war, The C0 2 doubt that other options must be prepared in produced by burning fossil fuels and clearing case they are required. However, until we forests accumulates in the atmosphere. Some know that it constitutes a serious problem the of the CO that is produced is absorbed in the 2 development of other options must be justified oceans, but the dynamics of the CO balance 2 on the basis that they will be cheaper or more are not well-understood. The concentration in attractive in some other way than properly the atmosphere is increasing by 5 percent per control led coal. year since 1958. C02 is transparent to most of the incoming sunlight that warms the Earth. CONVENTIONAL NUCLEAR Normally much of this is radiated back to Conventional nuclear plants totaling 55,000 space in the form of infrared radiation, but MW of power are now operational and another CO, tends to absorb and block this longer 106 reactors totaling 118,000 MW are either on wavelength radiation. This mechanism, the 5 greenhouse effect, is an essential ingredient in order or under construction. This is a substan- maintaining the proper temperature balance tial base for the nuclear technology, but it is on the Earth. However, if sufficient quantities questionable whether it will be fully realized of CO are added to the atmosphere, addi- or expanded because of public opposition, 2 licensing problems, tional heat will be trapped to warm the Earth financial uncertainties, significantly. and eventualIy resource Iimitations.

A number of studies of atmospheric CO2 Public opposition has been especially visi- levels predict that concentration will rise to ble. While public opinion polls still show sup- two to eight times today’s level in the 21st and port for nuclear energy, this support has been 22d centuries. While there is continuing discus- weakened for several reasons. Low-level radia- sion about the effects of this buildup, the mation release and other problems with routine jority of the scientific community agrees that operations contribute to public concern. Pub- the probability of global warming and other lic support has also eroded because of con- climate changes is sufficiently high to warrant tinued lack of a suitable site and demonstrated exceptional attention.4 Changing climate pat- means for nuclear waste disposal. Further mis- terns, even if they turned out to be ultimately haps such as the accident at Three Mile Island beneficial, would cause enormous disruption, could condemn the technology in the eyes of especially with agriculture. At least 10 years many who now reluctantly accept it. Finally,

4 0ffice of Technology Assessment, U S Congress, The Direct ‘Department of Energy, “U S Central Stations Nuclear Gener- Use of Coal, OTA-E-86, 1979 ating Units, r’ September 1980 108 ● Solar Power Satellites

the possibility that nuclear energy could con- $2 billion. Not many utilities can raise that tribute to nuclear weapons proliferation dis- much capital, even when the projected costs turbs many, though it is debatable whether of power at the busbar are favorable. Even renunciation of the nuclear option by the now, many plants are being built as joint ven- United States would materially reduce this tures by several companies. A continuation of risk. high interest rates could delay many plans for capital-intensive projects. And after an expen- Most of these problems, except prolifera- sive reactor starts operation, the utility bears tion, can be ameliorated by improved technol- an additional economic risk due to the possi- ogy, procedures, and regulations. But if im- bility of unplanned shutdowns. The Three Mile provements are not made quickly, public Island (TMI) accident and the Browns Ferry f ire opinion could swing against nuclear power in led to lengthy shutdowns that forced huge ex- the United States as it has on occasion in other penditures by the owner utilities, which then Western democracies (e.g., Sweden and Aus- had to generate or buy expensive replacement tria). Even if opponents remain in a minority, power. The present financial difficulties of the they can find many opportunities to trouble owner of Three Mile island, General Public the industry through legal actions, regulatory Utilities, illustrate how critical this concern appeals and ballot initiative. None of these will be for other utilities. may kill a particular project, but they could discourage utility executives from choosing Availability of fuel will eventually be a the uncertainty and frustration associated with serious constraint if conventional reactors are nuclear power as long as they have other op- used in the midterm to long-term future, with- tions such as coal. out a shift to advanced nuclear breeders. The Committee on Nuclear and Alternative Energy Utility decisionmakers also have to consider Systems (CONAES) estimated that enough ura- licensing and financial uncertainties. At pres- nium exists in this country to fuel at least ent, many design criteria for nuclear plants are 400,000 MW for the lifetime of the reactors (40 so poorly defined that it is virtualIy impossible years). ’ This would allow the construction of to get a new reactor licensed. ’ This problem another 227,000 MW of capacity. If ordering of may be resolved over the next few years, but new reactors resumes in 1985 and continues at recent trends have not been reassuring. For in- the rate of 10 reactors per year, the last one stance, a review now underway—to determine wouId be ordered in 2008. Because of retire- if fundamental changes in reactor designs are ments, by 2050 nuclear power would be back necessary to contain melted fuel cores in case to near its present level. Peak energy output of severe accidents— is expected to last sev- under this scenario would be about 5.6 (end eral years. use) Quads in 2015. However, discovery rates Some regulatory rulemaking problems stem for uranium ore and imports and exports of from a lack of conclusive data. Others appear uranium could change the total availability in to reflect the Nuclear Regulatory Commis- an unpredictable way. sion’s lack of a clear picture of what it wants The greatest single long-term uncertainty to accomplish and how to do it. Both types of facing the industry is the future electricity uncertainties have to be resolved before the growth rate, just as it is for the SPS. Over the utilities wiII consider ordering many more reac- next several decades, moderately high growth tors. rates might require much more nuclear power, Utility companies also face uncertainty con- but as discussed in this chapter, the growth cerning both the capital available to build rate may be more modest. However, low plants and the risk of a long-term shutdown. growth need not preclude nuclear, and might The cost of a new nuclear plant is now close to ‘f nergy In Transition, Committee on Nuclear and Alternative ‘Office of Technology Assessment, U S Congress, Nuclear Energy Systems (CONAES), National Academy of Sciences, Powerp/ant Standardlzat/on, OTA-E-1 34, April 1981 VVashlngton, D C , 1979 Ch. 6—SPS in Context Ž 109

enhance the attractiveness of nuclear com- it is not restricted for use with a single plant. A pared to other future central power options, recent study by the National Academy of such as SPS, that require large deployments to Sciences’ concludes that when wind, photovol- justify the development cost. taics, or solar thermal is used in a utility system, “it is typically not desirable to have Nuclear energy can have a future if its prob- dedicated storage but wiser to provide the lems are addressed effectively and decisively. backup energy from the grid.” Except for a To some extent this is happening. The accident small amount of storage to handle short-term at TM I has revealed weaknesses in reactor variations of sunlight in solar thermal applica- plant design and operator training, to which tions, the conclusion that dedicated storage is the industry and the NRC are responding with not appropriate for terrestrial renewable elec- initiatives such as the Institute for Nuclear tric technologies is generally well-accepted. Power Operations and the Nuclear Safety Analysis Center. As a result of the events in the Currently, electrical generation is fueled past 2 years, both regulators and utilities seem largely by oil, natural gas, coal, fissionable more conscious that extreme safety is in every- material, and stored water. For the time period one’s interest. when the SPS is most likely to find applicabili- Whether these measures will ensure safety ty, there may not be as great a diversity of in the future and enhance the industry’s public energy supply technologies connected with the image without pricing the technology out of utility grid as is now enjoyed; hence terrestrial reach is still an open question. solar technologies may be used in a different mode than the one that seems most desirable FIVE FUTURE TECHNOLOGIES now (i. e., peaking or intermediate). It is also The following discussion summarizes the desirable to compare all the future electric salient characteristics of the four central technologies on a common basis. For this renewable or inexhaustible energy technol- reason, OTA has prepared cost estimates for ogies that have been chosen for comparison solar thermal and photovoltaics operating in a with the SPS. While each of these alternatives baseload mode. Because photovoltaics also is compatible with centralized electricity pro- possess the unique property among these duction in a utility application, they are not future energy systems of being modular on a equally applicable for baseload power produc- very small scale, its use in a dispersed mode— tion. Photovoltaics and solar thermal sources both connected to the electric grid and inde- vary over the course of a day and the season in pendent of it– will be discussed in a separate a fashion that makes them well-suited for section. In the future, it would be also worth- peaking applications. Fusion, the breeder and while to compare SPS to an energy scenario SPS would work most efficiently producing composed of a number of dispersed solar tech- constant power 24 hours per day, so they are nologies working in complementary fashion. naturally suited for baseload power produc- The following discussion will give the major tion. The applicability of photovoltaics and characteristics, cost sensitivities and uncer- solar thermal can be broadened to cover in- tainties, factors affecting deployment, and termediate and possibly baseload applications foreseeable impacts of the different renewable by the addition of storage capability, but over and inexhaustible energy sources. First, a short the next 10 to 20 years there may be little summary of each technology will be given, fol- cause to do so, for two reasons. The first is that lowed by comparisons. Table 15 presents the the most cost-effective application of solar relevant characteristics of each of the 5 tech- thermal and photovoltaic systems is likely to nologies in matrix form. be as fuel savers until all the oil and gas-fired generating facilities have been retired from *“Energy Storage for Solar Applications,” Committee on Ad- utility systems. Second, electric storage is far vanced Energy Storage Systems, National Academy of Sciences, more versatile and cost effective for a utility if 1981 110 ● Solar Power Satellites

Table 15.—Characteristics of Five Electrical Technologies

Criteria Fusion Breeder SPS Solar thermal Photovoltaics Plant description Scale of power 500-1,500 MW 500-1,500 MW 1-100 GW (lasers 10 kW to greater 10 kW-100 MW output smaller) than 100 MW Power output in Baseload Baseload Base load Peaking, intermediate, Peaking, intermediate, relation to load baseload (with stor- baseload (with storage profile age, but expensive at expensive) high-capacity factor) Versatility Also large-scale, high- Also large-scale, low- Centralized, limited ver- Also cogeneration, Cogeneration? temperature process temperature process satility. Some military high-temperature proc- - heat; synfuels, pro- heat; synfuels; pro- connection and ess heat duction of fissile duction of fissile relevance to space materials materials colonies and space manufacturing Complexity High Medium High Low Lowest Reliability Between 0.6 and 0.75 Same as LWR (fuel No good reason to Between 0.6 and 0.9, Greater than 0.9 ( = 1- cycle reliability?) think it’s worse than Iike other steam time for repair) steam technologies. plants Between 0.6 and 0.9 (laser-exception) Nominal capacity 0.6 to 0.75 Same as LWR Between 0.6 and 0.9 Without storage: 0.2 to Without storage: 0.2 to factor 0.25. With storage: UP 0.25. With storage: UP to 0.9 to 0.9. Also depends on region Material Design specific, can None Can design around, Plentiful, domestic Plentiful, domestic requirements design around; stay common material, so- materials; need to materials, like nuclear away from specialized phisticated process- build manufacturing alloys ing industry Labor Like LWR Like LWR Few and skilled for Moderate to large, de- Moderate to large, requirements space construction, centralized larger decentralized larger less skilled for receiver construction Land Same as LWR. Less Same as LWR Comparable to other 5 to 10 acre/MW 10 acre/MW incre- requirements than 1 acre/MW (in- centralized solar mental addition could cluding fuel cycle) systems; 6.5 be zero acres/MW or less Construction 5 to 12 years? 5 to 12 years (including Similar to other cen- 5 years for 1OO-MW Short; minimum 48 Ieadtime licensing) tralized technologies, plant hours for 7 kW 5 to 12 years Lifetime Greater than 30 years Greater than 30 years Greater than 30 years; Greater than 30 years Greater than 30 years (first wall material) (replace steam design like other generator; systems, but limited experience Costs of RD&D $20 Billion to $30 $10 billion to $15 $40 billion to $100 Low $0.5 billion plus $1 billion to $2 billion billion (?) billion to achieve first $0.5 billion to $1.0 operating satellite billion Net energy Unknown l-year payback 2- to 20-year payback 1- to 2-year payback 2- to 20-year payback balance Operating costs Almost no fuel costs. 1 to 2¢/kWh 0.3 to 1.5¢/kWh; low as 1 to 4 percent of capital 1 percent; $20/kW/yr; Same as LWR, but percentage of costs; $40 to less for centralized less confidence delivered cost $60/kW/yr Capital costs $2,000 to $2,500/kW; $1,500 to $2,000/kW $1,500 to $17,000/kW $1,500 to $3,000/kW $2,000 to $3,000/kW lower for a 5-GW plant (peak) ($1.60 to $2.20/PW) (without storage) T&D costs Same as any central Same as any central Similar or greater than Centralized—same as Centralized—same as system system other central systems other systems; decen- other systems; decen- (reliability). Need to tralized is negligible tralized is negligible consider outage problem Decommission- Minor Minor Push out of orbit. Small Negligible Negligible ing costs at 4-percent discount rate over 30 years Impacts Institutional im- Similar to present Similar to present Requires new manage- Decentralized— medi- Decentralized— medi- pacts (owner- institutional structure institutional structure ment organization; in- um to high impacts; urn to high impacts; ship) ternational involve- centralized— similar centralized— similar ment possible to present infra- to present infrastructure structure Ch. 6—SPS in Context ● 111

Table 15.—Characteristics of Five Electrical Technologies (continued)

Criteria Fusion Breeder SPS Solar thermal Photovoltaics

Safety and health Safer than PWR Fuel cycle? Same as Microwave bioeffects Small risks PWR (higher power uncertain; ionizing Low; possible safety density, lower radiation in GEO hazard with decentral- pressure) ization in event of fire Environmental Small for routine opera- Small for routine opera- Upper atmosphere ef- Small Low possible manu- risks tion tion fects uncertain facturing risk of PV National security Designs other than Significant weapons Not efficient weapon None, possible benefits None, possible benefits implications hybrid less significant Proliferation potential but transportation ca- of exporting benign of exporting benign than breeder - pabilities significant technology are good technology are good Military Same as any central Same as LWR Slightly greater than Low Low vuInerability ized powerplant other central powerplants, depends on space capability of other nations Deployment considerations Time to commer- 30 years plus (Developed) 15 to 20 Long (greater than 20 Between 5 and 10 years Decentralized—5 years; cialization years domestic (Iicen- years) centralized— 10 years sing) Geographic Ioca- Low population area Low population area Low population, no Decentralized—very Decentralized—very tion with re- water needed; mixed close; centralized— close; centralized— spect to load S. W.-less than or S. W.-less than or centers equal to other sys- equal to other systems. Geographic de- tems. Geographic dependence high pendence high Compatibility Good Good Penetration may be Iim- Goes down with higher Goes down with higher with other tech- ited to 20 percent. percentage penetra- percentage penetra- nologies and Competes with other tion; negligible prob- tion; negligible utility grid technology. Nothing lems obviously unsolvable Other Probability for Low to medium High Low to medium High High commercial success Demonstration Large, but not as large Moderate cost for 500 Large cost (0.3 to 1 Small (1OO-MW Small (community sys- requirements as SPS to 1,000 MW. About $1 GW) aggregate of 2 to 3 tems are medium) billion demos) Resource None None Manageable Small Small constraints Risks of RD&D High, but for next 10 Technology is here, but High—big program; Negligible Negligible failure years little risk, $20 public views regarding depends on program billion waste? size (wait until HLLV available) Relative High, complex Small High Small (O&M costs) Cell costs uncertainties Is it a viable ex- Yes Proliferation? for de- Yes, if t works Easier to digest in Easier to digest in ample for the veloped countries small to moderate small chunks; need rest of the only? chunks manufacturer capac- world? ity, but good example Nature of RD&D Magnetic—public; Much public money Public funds for Needs to be demon- Need not be demon- process inertial —classified spent, remainder RDD&T. Then private strated by Government strated by Govern- might be private, but capital with private partici- ment, large private for regulatory uncer- pation; industry will contribution tainties develop

SOURCE: Office of Technology Assessment. 112 ● Solar Power Satellites

1. Central Solar Thermal.– Solar thermal its effective capacity factor will be about 23 technology is the oldest of the technologies percent in a location such as the southwestern under study. It may also be the one that is United States. Addition of a modest amount of nearest to commercial application, since a storage (sufficient for 3 hours of extended pilot plant is already under construction in this operation per day) will increase the capacity country. The concept involves simply collect- factor to about 40 percent and make it possi- ing concentrated solar radiation to heat a ble for the plant to supply part of the late- working fluid in a central receiver (boiler), afternoon electric consumption peak that oc- which in turn drives a turbine to generate elec- curs in many utilities. Because it is desirable to tricity. It has the versatility to provide either smooth out the effects of short periods of electricity or process heat (steam) for in- cloud cover, it is likely that the technology will dustrial applications. incorporate at least a small amount of thermal storage (up to 1 hour). Solar thermal plants Two generic systems have been proposed for could be made to operate in a baseload mode the solar thermal approach: line-focus and with the addition of a large amount of storage, point-focus systems. In the line-focus scheme, but this increases the system’s conversion loses the Sun’s radiant heat is reflected and focused and raises the overall cost per kilowatt in- by parabolic trough mirrors onto tubes con- stalled. Solar thermal will, therefore, probably taining the working fluid. The working fluid is be better suited for intermediate or peaking pumped to a central site where it may be used uses since its daytime availability corresponds to drive an irrigation pump, produce hot water closely with the peak of the electricity load or steam for a factory, or produce a combina- profile in many areas. tion of heat and electricity for a small community. The line-focus approach is also Solar thermal plants will be intermediate in favored for process heat applications such as scale between today’s coal or nuclear plants enhanced oil recovery, but is not being ac- and small onsite generators. They can be ex- tively considered by DOE for central electric pected to be deployed relatively quickly– per- applications. haps within 5 years for a 100-MW plant. In the point-focus or “power tower” system, The technical feasibility of solar thermal a field of reflectors (called “heliostats”) is technology is established. Engineering ques- focused on a central receiver atop a tower in tions remain about the materials to be used in the center of the field. Although there are the design of the central receiver. What is at several designs, a heliostat is basically a flat stake in making the technology commercially reflective surface mounted on a computer- viable is whether plants can be produced eco- monitored gimbal that allows it to automati- nomically. The single most important factor is calIy track the Sun’s course across the sky. The the cost of heliostats, which accounts for heliostat/power tower approach is being pur- about one-half the cost of solar thermal de- sued by DOE as a central generating system, signs. Present cost estimates range from $1,000 though not exclusively so. * It can be used for to $3,000/kW of capacity installed. electrical generation either in a stand-alone Much of this high cost reflects the cost of system or as a method for repowering existing materials. Savings realized from future auto- fossil-fueled power stations. The place of solar mated production techniques are built into thermal in a utility system —whether it serves these projections. Thus, the economic viability as a peaking, intermediate, or baseload unit— of solar thermal technology depends on attain- depends on the storage capability of the solar ing heliostat cost goals. thermal plant. Without any auxiliary storage, The research, development, and demonstra- *In 1980, DOE initiated six major studies of the applications of tion (RD&D) costs associated with the solar the power tower to a variety of industrial heat demands, ranging from low-quality steam for uranium leaching to high-tem- thermal development are expected to be in the perature steam for reforming methane to ammonia, range of $0.5 billion to $1 billion. In addition Ch. 6—SPS in Context ● 113 to continuing tests and studies to reduce helio- even though costs have dropped and per- stat costs, R&D for efficient and cost effective formance improved over the past decade storage methods, improved receiver designs in line with DOE projections. Further cost and transport fIuids are also needed. reductions to ($95/m2) $0.70/peak watt) and performance improvement to 13.5- 2. Solar Photovoltaics. This technology is the percent efficiency are the DOE goals for newest of the terrestrial solar options under 1986. study and it is conceptually the simplest, since ● The cadmium sulfide/copper sulfide tech- it converts sunlight directly to electricity nology is another approach that is com- without any working flu ids, boilers or genera- mercialIy available and holds promise for tors. Because the essential element—a semi- improvement. This material can be used conductor wafer or “cell” — is modular at a in thin films because of its high ab- very small size, the technology has a versatility in scale of deployment that surpasses any sorbance of sunlight, with a reduction in fabrication costs and materials require- other option. Photovoltaic (PV) cells have already proved feasible in small-scale applica- ments. Experimental cells have achieved tions for both space and terrestrial purposes. efficiencies of 9 percent, with limited lifetime. Improved cells have the poten- However, central PV systems have not been 2 tested yet, even in a pilot plant size. Because tial for cost reductions to $10/m at 10- percent efficiency. A number of other the technology is so intrinsically modular, the R&D program is not geared to the demonstra- cadmium sulfide technologies are under study for thin film and standard cells. tion of a series of prototype plants but to the ● improvement of the cost and performance The gallium arsenide technology is characteristics of the celIs. another alternative that has achieved efficiencies up to 24.5 percent in experimen- A variety of different semiconductor materi- tal cells. The material can be fabricated in als is being developed for possible use in cen- thin films (with experimental efficiencies tral PV systems. When sunlight falls on wafers to 15 percent) and can withstand concen- of these materials, it produces a direct current trated sunlight at high temperatures. Its of electricity. The efficiency of this process major disadvantage is that commercial depends on many semiconductor properties, production is still some time away and and how well those properties match the wave- costs remain much higher than for single- length spectrum of sunlight. Typically, the crystal silicon. materials produce a direct current (DC) voltage ● The polycrstalline and amorphous silicon level of about 0.5 volts. Some of the more technologies have the potential for orders promising PV developments include the four of magnitude cost reductions compared technologies discussed below. to the single-crystal silicon technology, but the experimental cell efficiencies • The single cell silicon technology is the have so far only reached 9 to 10 percent. most highly developed, and its introduc- (The probable maximum is estimated to tion dates back 23 years to the beginning be at least 15 percent for the amorphous of the National Aeronautics and Space technology in thin film cells.) These tech- Administration (NASA) space program. Its nologies are not limited to silicon, but are properties are well understood and cells currently being investigated along with sold commercially for small-scale applica- other novel materials concepts. tions routinely achieve efficiencies of 10 to 13 percent; experimental cells have All the technologies discussed above are achieved 15 percent and the theoretically candidates for use in flat-plate arrays of cells probable maximum is 20 to 22 percent. that absorb unconcentrated sunlight. Gallium The single most important barrier to com- arsenide is also an example of a high-effi- mercial use is the high production cost, ciency material that can be used with a con-

174 ● Solar Power Satellites centrating system. Concentrating systems in- A central plant might produce 200 MW from 8 volve different tradeoffs and are further from modules. Storage could be added to extend the commercial viability than flat-plate systems. capacity factor of the plant, at additional Both line- and point-focus collectors are under system cost. As discussed in the introduction consideration for PV concentrating systems. to this section, the economic merit of Costs of concentrating systems can in principle dedicated storage for utility-based PV systems be low, since the receiving area needs only to has been seriously questioned. be covered with a thin reflective sheet, but the The pace of technological breakthroughs in technology is not developed enough to make PV technology is impressive. Today single- project ions yet. crystal silicon cell arrays cost 15 percent of Up to half the cost in a flat-plate design ter- what they did in 1974, as can be seen in figure restrial solar photovoltaic plant today is for 27. It is on further orders-of-magnitude cost the cells themselves. Other requirements for a reductions that both terrestrial and SPS PV complete plant are materials for packaging systems depend. Such price reductions are and supporting arrays of celIs, support struc- common in the semiconductor industry for tures, cabling to connect the arrays and products with large markets (e.g., digital modules, and power conditioning equipment watches, hand calculators, and now hand com- to convert the DC voltage to alternative cur- puters), but they are nearly unheard-of in the rent compatible with the utility grid. About 300 energy industry. Therefore, planners familiar cells would be combined into one panel, 30 with conventional thermal and nuclear energy panels into one array, and 10,000 arrays into technology sometimes find them difficult to one module supplying 25 MW of peak power. accept. The goals for the DOE PV program are

Figure 27.— Recent and Projected Solar Photovoltaic Prices

n Ch. 6—SPS in Context ● 115

for array prices of $2.80/peak watt in 1982, and 0.7 percent U-235. Only the U-235 is usable $0.70 in 1986, and $0.15 to $0.40 in 1990 (all in directly in a conventional reactor. With con- 1980 dollars). At the 1990 level, complete sys- ventional reactors, uranium resources would tems are expected to cost $1.10 to $1 .80/peak be exhausted relatively rapidly by an expand- watt. ing nuclear energy base. Breeder reactors on the other hand, can extract 100 times as much Although significant breakthroughs have oc- energy from a ton of uranium ore and thus ex- curred in the past 5 years, the principal thrust tend the nuclear energy resource by several of PV research is still directed toward the iden- centuries. tification, selection, and engineering refinement of the cheapest possible semiconductor In a breeder, the core of the reactor is sur- materials. A concomitant part of this effort is rounded by a blanket of the type of uranium the development of suitable mass-production not burnable in conventional nuclear plants. techniques (now being most intensively pur- This uranium captures neutrons escaping from sued for single-crystal silicon and cadmium the chain reaction in the core and is trans- sulfide) to open the way for mass market muted into plutonium, a premium value penetration. It is upon the outcome of this nuclear fuel. In this fashion, a breeder two-pronged effort (development of cells and “breeds” new fuel that is extracted from the development of better manufacturing tech- blanket, converted into fuel rods, and later niques) that the success of central terrestrial burned in the same or another reactor. An ad- PV plants will depend. vanced breeder will produce about 10 percent The time-scale for commercial readiness of more fuel than it burns. A different fuel cycle central terrestrial PV plants could be as short could use thorium in the blanket. Thorium is as 5 years or as long as 15 years. The balance of an element similar to uranium, but it cannot be a central PV plant uses familiar building used directly as a fuel. In the blanket, it materials and readily available power-handling transmutes to U-233 which is a good fuel. equipment. Once arrays are available, plant construction Ieadtime should be short. Ac- Breeders may also be distinguished by the cording to the DOE program, commercial different types of coolants used to carry heat readiness could occur in the early 1990’s. If the from the core to the generating side of a RD&D program for PV cells is accelerated this nuclear plant. Because the interconnections date could be earlier; on the other hand, slip- between the core and the generators are quite page in the schedule for cell development complex, requiring considerable engineering could delay commercial introduction. refinement, the choice of coolant defines conceptually different types of breeders as much Subsequent deployment of central PV sys- as or more than the choice of fuel. Early in tems would be paced by the rate of growth of its program, the United States emphasized national manufacturing capacity for PV cells. breeders with liquid metal (usually molten To achieve substantial penetration of central sodium) coolants and the reactor concept that PV in the time period of 1990 to 2010 will re- evolved —the liquid metal fast breeder or quire an aggressive program for PV man- LMFBR– has become the reference system for ufacturing plants. It is possible that decen- breeder research in other countries, represent- tralized PV centralized terrestrial and SPS ing more than 95 percent of the dolIar effort energy systems could all be competing for the devoted worldwide to breeders. Thirteen reac- output of the PV industry during this period. tors using the LMFBR concept have been built, 3. Advanced Fission (Breeder Reactor).– Con- the most successful being the French Phenix ventional reactors use uranium ore very ineffi- reactor, and seven countries with major ciently because only a small fraction of the breeder programs (table 16) have all empha- uranium is tapped for energy. Natural uranium sized the LMFBR type. Alternatives are helium consists of two isotopes 99.3 percent U-238 gas, molten salt coolants, and water. 116 ● Solar Power Satellites

Table 16.—Description of Milestones of Major Breeder Programs

Federal Republic France of Germany Japan Reactors Rapsodie (24 MWt) KNK-I (58 MWt) Joyo (100 MWt) Phenix (250 MWe) KNK-11 (58 MWt) Monju (300 MWe) Super Phenix (1,200 MWe) SNR-300 (300 MWe) SNR-2 (nominally 1,600 MWe)

1. 1960—GFK, Karlsruhe project 1. 1967-Joyo conceptual design begins 2. 1969—Joyo safety evaluation 2. 1964—Design study for 1,000 MWe 3. 1970—Joyo construction begins LMFBR 4. 1977—Joyo goes critical 3. 1966—SNEAK startup 5. 1968—Monju preliminary design 4. 1975—SNEAK experiments for SNR 6. 1969—Monju conceptual design 300 7. 1973—Monju safety evaluation 5. 1967—INTERATOM F.R.G. and 8. 1978—Monju construction begins BENELUX cooperation begins -10. 1986—Demo plant begins 6. 1972—KNK-I goes critical -11.1991 —Demo plant goes critical 7. 1976—KNK-11 goes critical -12. 1988—Commercial plant 1 con- 8. 1969—SNR-300 safety report struction begins 9. 1970—SNR-300 company established critical 10. 1971—SNR-300 revised safety report -14.1991 —Commercial plant II con- 11. 1972—SNR-300 sodium fuel pumps struction begins tested 12. 1973—SNR-300 construction begins critical 13. 1974—SNR-300 steam generators and IHX test 14. 1975—SNR-300 specification of fuel and cladding 15. 1980—SNR-300 goes criticala 16. 1974—SNR-2 company established 17. 1976—SNR-2 preliminary designa 18. 1981 —SNR-2 construction beginsa

as~h~d”l~ as of 197& In 1980, the SNR program currently in flux. SNR-301) designed but not yet licensed. SNR-2 not Yet designed. Entire Pro9ram will sli P substantially, but the new schedule is not known at this time. SOURCES: France: U.S. Energy Research and Development Administration, The LkfFBR Program In France, ERDA 76-14, March 1976; M. D. Chauvin, “The French Breeder Reactor Program,” 1976. Federal Republic of Germarty: U.S. Energy Research and Development Administration, The /_ J14FBR Program in Germany, ERDA 76-15, June 1976. Jepem Report of Ad Hoc Study Committee organized by Japanese Government Science and Technology Agency, October 1977. SOURCE: International Energy Associates Limited, 1980.

United Kingdom United States U.S.S.R. Reactors DFR (60 MWt) Clementine (25 kWt) BR-5 (10 MWt) PFR (250 MWe) EBR-1 (1.2 kWt) BOR-60 (60 MWt) CFR (commercial size) Fermi (200 MWt) BN-350 (1 ,000 MW) EBR-11 (16.5 MWe) DN-600 (600 MWe) Clinch River (375 MWe) Fast Flux Test Facility (equivalent of 160 MWe) PLBR (commercial size) CBR (commercial size)

1. 1953—first nuclear power program 1. 1946—Clementine goes critical 1. 1958—BR-5 goes critical begins 2. 1951—EBR-1 goes critical 2. 1965—BR-5 operates full core 2. 1964—second nuclear power pro- 3. 1963—Fermi goes critical 3. 1969—BOR-60 goes critical gram begins 4. 1966—Fermi shuts down 4. 1973—BN-350 goes critical 3. 1963—DFR goes critical 5. 1983 -EBR-II goes critical 5. 1973—BN-600 construction begins 4. 1984-PFR construction begins 6. 1971–SEFOR (U.S. and F. R. G.) 6. 1979—BN-600 goes critical 5. 1972—PFR goes critical goes critical 7. 1975—1,600 MWe reactor design underway Ch. 6—SPS in Context ● 117

Table 16.—Description of Milestones of Major Breeder Programs (continued)

United Kingdom United States - U.S.S.R.

aThi~ ~a~ the IJ,S, program in 1978, Currently there ,~ no planned pLBR schedule, penal Ing final ~eclsions on CRBR. CRBR iS “in Construction, ” but has been in a holding pattern for 2 years. SOURCES: United Kingdom: Prepared by IEAL from compilation of U.K. documents. United Statas: U.S. Energy Research and Development Administration, .LIquKI k4efa/ Fast Breeder Reactor Program, January 1977; U.S. Energy Research and Development Administration, The LMFBR Program in France, ERDA 76-14, March 1976; Ford Foundation, Nuc/ear Power Issues and Choices: Report of the AJuc/ear Energy Po/icy Study Group, 1977. Note on U.S. program: Items 9-15 refer to the program as it stood in April 1977, The plan and schedule has been in revision since then, but it is not yet available. U. S. S. R.: United States Nuclear Power Reactor Delegation, “Report of the ~Jnited States Nuclear Power Reactor Delegation Visit to the U. S. S. R,, June 1-13, 1975,” 1975. SOURCE: International Energy Associates Limited, 1980. As a source of centrally generated electric- erators) are not extrapolatable to commercial ity, the breeder has been proven feasible at the size. France, together with the Federal pilot plant scale and at an intermediate Republic of Germany and Italy, is now build- scale but awaits demonstration at commercial ing a 1,250-MW reactor incorporating an im- scale —that is the 1,000-MW size of new con- proved design – Superphenix – at Creys- ventional reactors. Its operating character- Malville. Due to go critical in 1985, it will be istics are expected to be similar to a conven- the first commercial prototype breeder. tional (light water) reactor, except that it will have higher thermal efficiency and therefore The time until commercialization of the less thermal pollution. Breeders may also in breeder is 5 to 20 years depending on which principle be used for industrial process heat. breeder technology (French or U. S.) is meant. The Russian breeder BNR-600 produces elec- On the face of it, commercial readiness will tricity and desalinated water. occur in 1985, assureing success of the Super- phenix. After that, France plans an aggressive The technology was demonstrated at a pilot program of breeder deployment, starting a new plant scale in the United States in 1963, when a plant every 2 years for the rest of the century. * 10-MW reactor named EBR-II started produc- The French central utility (EdF) has already ing electricity in Idaho. Between the 1960’s ordered the first two of these “commercial” and 1970’s, technical leadership shifted from plants. Progress on the U.S. plant comparable the United States to France. The Phenix which to the Phenix (the Clinch River breeder) has has produced electricity for more than 5 years stalled, and its technology is outmoded in at Marcoule, France, demonstrated successful some respects. Some argue this intermediate scaling from 10 to 250 MW, but suffered some plant step should be skipped to go to a com- technical problems that required the plant to mercial-size or nearly commercial-size plant. shut down for more than a year. Its breeding ——— rate is considered too slow for commercial use, *A reevaluation of these plans is apparently underway in and some components (especially steam gen- France following the recent election 118 ● Solar Power Satellites

The Ieadtime for constructing a conventional questions are less important. Unless the nuclear plant in the United States is 12 years breeder costs are so high that it is uneconomic and design and construction of a full-scale compared to other options, the major concerns breeder prototype under the same ground rules are related to light-water reactors. These will could take 15 years. Thus, U.S. breeder tech- not greatly affect the SPS decision. nology could be commercialized sometime in Deployment of the breeder is predicated on the 1990’s, depending on the development se- the continued expansion of light-water reac- quence. tors. The problems facing the industry are The major difference between the French complex and difficult as discussed in the sec- and American technologies is whether the tion on conventional nuclear reactors above. If reactor vessel uses a “loop” or “pool” method these problems are not resolved, the fission op- of bathing the core with Iiquid sodium coolant. tion will be foreclosed, at least as a major The pool method is simpler, has more thermal energy source. Fusion may also be threatened. inertia, and is considered by the French to be The breeder exacerbates some of these prob- an added safety factor. The loop method is lems. Proliferation of nuclear weapons will be more similar to conventional reactor technol- considerably harder to control if breeders are ogy and has been tested on an intermediate- worldwide articles of commerce. While this scale U.S. breeder used for fuel development might not have a direct bearing on a utility’s (the FFTF). Britain and France espouse the pool decisionmaking process, the safeguards imp- approach; the United States and Japan use the lemented to prevent diversion might be quite loop method; and the Soviet Union and the onerous, and public opinion could be hostile. Federal Republic of Germany are testing both. Health and safety issues will be important because of the plutonium and the operating In principle, a U.S. utility could order a characteristics of the reactor. Waste disposal Superphenix reactor now for delivery in the will not be qualitatively different, but the vast- early 1990’s and in that sense the breeder ly greater potential of breeders to produce could be said to be commercially available waste make the problem greater, especially if already. But no utility would invest in a central disposal sites are difficult to find. While these nuclear plant without reasonable assurance it problems, individually or collectively, need would be reliable and could be Iicensed in this not be overwhelming, they can all adversely af- country. The licensability of the French tech- fect a utility’s inclination to order a nuclear nology is an open question. pIant. As long as a utility has a choice within a The RD&D cost of commercializing the reasonable economic range, it is likely to breeder is uncertain because the national select the less controversial options. Thus, policy for 1976-80 was to not deploy the while breeders could in principle supply all the breeder. It is also dependent on the demon- electric power needed in the 21st century, they stration strategy chosen (i. e., whether to go may in fact supply Iittle or none. straight to a commercial prototype). Estimates 4. Fusion.– Of the future energy sources made by the U.S. program managers in 1975 of considered here as competitors to the SPS, fu- $10 billion to $15 billion for commercial dem- sion is the furthest from realization. Fusion onstration should stilI apply. consists of nuclear reactions that are created The obstacles that the breeder program by bringing together light nuclei at speeds must overcome before commercialization are great enough to exceed their mutual repulsive not primarily technical. There is little doubt force. The result of this reaction is the creation that a strong breeder RD&D effort could result of nuclear energy that is carried off by neu- in a reactor that utilities could order in a few trons and/or charged particles, depending on decades. The questions are economic and in- the nature of the reactants. In order to create stitutional and generic to nuclear power. For this reaction it is necessary to: 1 ) raise the the purposes of this discussion, the economic temperature of the fusion fuel to very high Ch. 6—SPS in Context ● 119

levels and, 2) confine the fuel for sufficient Particular difficulties in understanding the time. The criterion to be met by these two con- behavior of the fusion fuel in its very hot ditions is that more energy is released by the (plasma) state explain why scientists have had nuclear reactions than is used to heat and con- so much difficulty making progress in fusion fine the fuel that is in a wispy, gaseous form research (which began in 1954). (plasma). Fusion is unique among future energy tech- Since the fusion reaction would be rapidly nologies because it has not yet been proven cooled by the reactor walls, containment by technically feasible—that is to say, no con- solid materials is not possible. Such an ap- trolled fusion reaction has yet operated in a proach would quench the plasma. This dif- self-sustaining fashion or produced electricity ficulty, incidently, would also make a fusion even on a small scale. It has a broad range of reactor easier to turn off, making it safer than potential applications, e.g., electricity produc- fission. Two alternate approaches are being tion, high temperature process heat, synthetic taken: using a magnetic field in one of many fuel production, and fissile fuel production. possible shapes that have been proposed, The fusion community can point to a recent (magnetic fusion); and using a laser or ion string of successful experiments as evidence beam to produce a miniexplosion of the fuel in that fusion is on the verge of a scientific solid form so that confinement occurs by the breakthrough. One of the goals is “break- inertia of the fuel (inertially confined fusion or even, ” meaning the achievement of positive ICF). The second approach draws on nuclear net energy production. DOE expects break- weapons work for some of its research and is even to be achieved before 1985, and a recent partially classified. The discussion to follow review by the research oversight board of will center on the magnetic approaches. DOE9 concluded that fusion was ready to Among different magnetic confinement con- move from the research stage to the engineer- cepts—or types of “magnetic bottles” —the ing development stage. Nevertheless, the leading contender is a toroidal shape called weaker understanding of the principles of con- the tokamak, after the Russian acronym given trolled fusion compared to other energy tech- by its inventors. As a reactor, it would be con- nologies means that more emphasis is neces- siderably more complex than a conventional sarily being placed on basic research. Con- powerplant. The mixture of deuterium and sequently, the engineering-related considera- tritium fuel planned for use in first-generation tions that influence commercial readiness and fusion reactors burns at a very high tempera- acceptability—that is the technical, eco- ture, 100 million 0 C. The natural current in a nomic, and environmental factors — are more tokamak system is not sufficient for heating uncertain than for breeders, solar thermal, PV the fuel that hot, so additional and complex or SPS. heating systems are required. The fusion core Despite the high degree of uncertainty, will be large enough that electrical losses in much more can be said about the engineering the magnets would be a significant drain on features of fusion than was possible a few the output of the plant, unless superconduct- years ago, based on a set of thorough and ing magnets are developed specifically for fu- detailed engineering studies. Using the toka- sion applications. Other complexities arise mak as a reference system, a powerplant is from the fuel requirements and operating re- likely to be in the range of 500 to 1,500 MW, quirements. Any fusion system must breed half with 1,000 MW being the nominal planning its fuel (the tritium component), and tokamak size. A tokamak fusion reactor would operate systems currently under development must as a baseload plant, with capacity factors, con- operate in a pulsed (few hour) mode rather struction Ieadtimes, plant lifetimes, land, than a continuous power mode. labor, and materials requirements similar to These factors make fusion more complex than either conventional reactors or breeders. 9ERAB Report (DOE), 1980 120 • Solar Power Satellites conventional nuclear plants. The high-tech- there is no conceivable possibility of a run- nology core would constitute a substantially away reaction. But first-generation fusion larger percentage of the total plant than for plants will use relatively large quantities of conventional (or breeder) nuclear plants, and tritium, a radioactive gas harmful to humans. fusion would have some unusual maintenance Advanced fusion fuel cycles would greatly problems that arise from the character of the reduce the quantity of tritium that must be fusion reaction itself. Since the nature of the handled. To make fusion safe, the problem of fusion core must be considered hypothetical handling industrial quantities of tritium with- until technical feasibility is proven, the eco- out routine small emissions will have to be nomics of fusion is perhaps the most uncertain solved. There will also be a substantial waste characteristic at this time. Two different engi- disposal problem, because the “first wall” of neering studies prepared at the University of the containment chamber for magnetic sys- Wisconsin 10 and Argonne National Labora- tems will have to be replaced every few years tory” put the busbar costs at 75 and 44 mills/ due to radiation damage. Since the replace- kW respectively (in 1980 dollars). able “wall” may be up to 1-m thick, the quantity of waste could be high, measured in the tens Because of the special character of fusion, or hundreds of tons per reactor per year. This estimates of the timetable to commercial read- material will be highly radioactive and wilI pre- iness vary widely. A recent survey of opinion sent a long-term waste disposal problem, found the majority of estimates to fall be- though the radioactivity will not be as long- tween 2000 and 2025, with some as early as Iived as conventional fission reactor wastes. 1990 and a few extending to the 22d century or The amount and lifetime of radioactive never. 2 It appears unlikely that fusion will be material can possibly be reduced substantially commercialized before 2010— the earliest Iike- by using other materials for the first wall Iy date for SPS – and the present DOE program without changing the nature of the fusion reac- is on a schedule calling for “demonstration” in tion. Analogous changes for fission reactors 2015, with the dates 1995 or 2000 considered are not possible since the waste material possible at increased cost. The DOE program generated is an inherent part of the fuel ele- calls for two steps after breakeven in 1985, the ment. Finally, fusion carries some proliferation first a fusion engineering demonstration in risk because the energetic neutrons of the fu- 1990 that produces thermal power but no elec- sion reaction comprise a high quality source tricity. Pending success with this plant, a fu- for producing weapons material. It is con- sion demonstration plant would be started by ceivable that unless proper safeguards are about 2000, that could produce 500 to 1,000 developed, a world full of fusion reactors MW of electricity. However, more steps are could be highly proliferation prone. However, likely to be needed prior to commercializa- there are many other technologies that are tion. Fusion research is in such an early phase available or could be available for the same vis-a-vis other technologies that it is difficult to purposes earlier, more readily, and more determine reliably the path to “commercial” cheaply than fusion. fusion. To a degree, fusion may also inherit the To be commercialized, fusion must also find public acceptance problems of nuclear fission. public acceptability. From an environmental, Fusion is a different technology, with fewer in- health, and safety standpoint, the principle ad- trinsic risks but greatly increased complexity. vantage of fusion over fission power is that But since it is a nuclear technology, even if it turns out to be relatively benign compared to ‘O’’ NUWMAK A Tokamak Reactor Design Study, ” Fusion En- fission, it may remain associated with conven- glneerlng Program, Nuclear Engineering Department, University of Wisconsin UWFDM-330, March 1979 tional nuclear power in the public mind. 1‘Argonne National Laboratory, Start;re “’’Chase Delphi Study on Fusion, First Round Results, ” Chase The greatest uncertainty in the development Manhattan Bank, September 1979 of fusion remains the physics associated with Ch. 6—SPS in Context • 121

breakeven. Although many of these uncertain- factors most important for the other central ties can be resolved by small experiments base load technologies. costing on the order of $1 million to $10 Scale of Power Output. – Plants must be million, complete resolution will still require a designed on a scale that can be readily inte- few large sophisticated experiments, costing in grated into the existing grid at the time of de- excess of $1 billion. It should be noted, ployment. Using the rule of thumb that no one however, that the nature of the fusion reactioc plant should comprise more than 10 to 12 per- is such that a demonstration reactor wouId recent of the system’s capacity to guarantee in- quire very little increase in scale or cost from tegrity of the grid during a plant failure, the these large experiments. The total cost to de- largest plant that could be presently accom- velop fusion to the stage of commercial modated by a single utility in the United States viability depends significantly on the cost of would be 2,500 MW, and that only by the Ten- this “hardware” and is projected by DOE to be nessee Valley Authority. (See ch. 9. for a $20 billion to $30 billion. If more than two ma- discussion of this issue.) Cooperative agree- jor steps are needed before a commercial pro- ments among utiIities on the same grid can ex- totype can be built, the cost will be somewhat pand the maximum acceptable size. Current higher. baseload plants generate from 500 to 1,300 5. Comparisons of Central Electrics. -Because MW. Both fusion and breeder plants are plan- each of these future electric technologies is ned to fit closely within this range. Very large designed for use in a central plant mode, they powerplants (greater than 1,500 MW) were the are best compared in the context of a utility rule in fusion planning several years ago, but company’s needs. If each of the different tech- encouraging new research results coupled with nologies were at the same stage of develop- new interest in smaller powerplants allowed ment, comparison based on projected power fusion engineering designers to direct efforts costs would be the most powerful and appro- toward conceptual designs in line with present priate method of analysis, particularly if all powerplant scales. Larger plants would mean were close to commercial maturity. But the improved economies of scale for the breeder five are at quite different states of technical (as it would for fusion), but for utility com- maturity — so much so that even the defini- patibility reasons (as well as licensability), the tions used for “commercial” maturity used in projected size of the breeder has also been the different programs may be qualitatively kept below 1,500 MW. different. Lacking information that may take 5 Solar thermal and solar PV pIants achieve to 20 years to acquire, a close look was taken their economies of scale at much lower out- at other characteristics, with particular atten- puts–100 to 200 MW maximum. Both can tion to properties–such as complexity, health function economically at still smaller scales. effects, and safety — which past experience has Photovoltaics are modular and economic at a shown to be closely related to both capital and few kilowatts or less. operating costs< Only the reference system SPS appears to After costs, the most important issue the have economies of scale that make it imprac- utilities must consider in deciding to risk tical at a size that can be accommodated by capital on a particular investment in a genera- the present utility systems. Whether it could be ting technology is the way in which a plant is accommodated in future utility systems de- expected to function and its associated im- pends on the growth of future electric de- pacts. Can the proposed technology be suc- mand. Smaller microwave systems or a laser cessfully integrated in the grid and meet the system would fit the utility grid more readily. associated requirements for reliability and capacity? These issues are discussed for the Reliability and Capacity Factor. – Prior to SPS in chapter 9. This section will highlight the the demonstration of a technology, both its

83-316 0 - 81 - 9 122 ● Solar Power Satellites capacity factor and its projected reliability are climate. In the Southwestern United States, the subject to considerable uncertainty. However, capacity factor of a plant without storage it is expected that breeders will operate much would be 23 to 25 percent. Storage for a solar as conventional light water reactors do today, thermal or solar PV plant redistributes the col- with capacity factors of 60 to 75 percent and lected energy to other times of day, but does forced outage rates (that is, unplanned shut- not appreciably change the amount of energy downs) of less than 15 percent. CoIIected per year per acre of plant area. The steam and electric generation parts of The SPS would circumvent the 25-percent fusion plants are expected to be similar to con- capacity factor limitation of terrestrial solar ventional reactors and breeders. But the fusion plants by being exposed in space to direct core will be much more complex than the sunlight 24 hours per day all year (except for nuclear parts of a conventional or breeder brief, predictable eclipses if located in geosta- plant. One indication of this is that the fusion tionary orbit, or unpredictable cloud cover if a core is expected to represent a much larger laser or mirror system). The question with SPS fraction of the plant investment (50 v. 10 per- is not solar capacity but availability. As with cent for nuclear). Because of the vast uncer- fusion, it is impossible to predict just how tainties surrounding the actual operating reliable the SPS wouId be. As a system it is very characteristics of fusion technology, it is im- complicated, involving a massive transporta- possible to predict what capacity factors and tion system, untried satellite technology, and forced outage rates are likely to be. It is clear large ground systems. Reliability factors as that to compete with breeders or light water high as 95 percent have been predicted for the reactors, fusion should be just as reliable and operation of the satellite and rectenna com- capable as they are. bined, 13 but they have not taken into account Solar thermal is a steam technology, with a the entire SPS system, including maintenance balance of plant that will be similar to, though and repair. Research on transportation and smaller than, that for a conventional baseload space platforms will provide considerable in- plant. The solar-thermal part will be chiefly sight into the expected reliability of the vulnerable to failure of the heliostats or the satelIite. boiler. The heliostat fields could have tracking or maintenance problems, the boilers could Complexity. –Given the extreme range of have materials and integrity problems due to physical requirements for a sustained, con- the high solar flux. Nevertheless, it is projected trolled fusion reaction, fusion is clearly the to operate with reliability similar to other most complex technology under considera- steam technologies —60 to 90 percent. tion, requiring a plasma hotter than the core of the Sun, powerful large superconducting Solar PV is the simplest technology, without magnets bigger than any yet built, and steam systems or moving parts or (necessarily) materials problems in a radiation environment high solar flux, if flat plate systems prove most more severe than that of the breeder. The economic. Because it is simple, the reliability reference system SPS is less complex than fu- of solar PV is expected to be very high (greater sion, since it uses more nearly proven technol- than 90 percent). There may be unsuspected ogies. Nevertheless, the overall engineering durability problems with some solar PV cells, and logistics problems of the SPS could make however. Although PV are an intrinsically sim- it an undertaking that approaches the com- ple technology, it currently has higher material plexity of fusion when all the technical hurdles and manufacturing costs than other alter- are considered. It should be noted, for in- natives. Both solar thermal and solar PV have an inherent limitation of plant capacity factor, due to the daily and yearly variation of am- ‘” SPS/Utlllty Grid Operations, ” sec 14 of Boeing Corp , re- bient sunlight, which differs with latitude and port No D 180-25461-3 Ch. 6—SPS in Context Ž 123

stance, that the SPS as it is described in the commercial prototype pIant. It is the cost of reference system could only begin to be lost opportunities in other areas for which the assembled as a system after major break- money could have been spent. A component throughs in two other technologies—space of the opportunity cost is the cost of the com- transportation and PV — are achieved. mercial prototype itself, which is the demonstration cost. The breeder is considerably less complex than either the SPS or fusion, but is more com- The busbar cost is the actual cost of produc- plex than conventional nuclear systems. The ing electricity with a technology when capital main potential difficulties are the nuclear costs, fuel costs (if any) and operation and properties of the breeder core, the peculiari- maintenance costs have been considered. For ties of the liquid metal coolant, and the poten- current technologies, these costs are well- tial difficulties of the breeder fuel cycle. known and therefore detailed comparisons be- Although these factors are incremental addi- tween technologies are possible. However, tions to the complexity of a nuclear pIant, they even for current technologies the task can be are the driving factors behind the projections difficult–witness the debate over whether that the breeder will cost 25 to 100 percent coal or conventional nuclear is cheaper. For more than a light water reactor (LWR). future technologies, the task is much more uncertain. Therefore, cost estimates of delivered The solar thermal plant is also a steam electricity are of Iittle use in deciding between system that has much of the complexity of technologies in early development stages. Fur- other steam systems, such as coal or nuclear, thermore, technologies reach commercializa- mitigated by the reduced size of the plant and tion at different times. Therefore, cost es- the modularity of the heliostat field. There timates for one technology are more reliable may be special problems in having a central than for another, with the most fully de- plant boiler at the top of a tall tower, but solar veloped technologies having the most thor- thermal plants appear to be less complex than oughly tested cost data. For example, coal nuclear, fusion or SPS technologies. Their com- plant costs are well known, but breeder costs plexity may be comparable to current base- are less so, and fusion costs are much less so. Ioad coal technologies. Though it is a current technology, the future Central PV plants have by far the least com- costs of PV for onsite, central, or SPS plants, plexity of the alternatives discussed here, for depend strongly on the future costs and effi- two reasons. First, the basic technology is sim- ciencies of PV cells and are consequently un- ple, modular, and should be manufactured certain as well. A final note on busbar cost es- cheaply if the experience with mass-produced timates is that as a technology matures, the semiconductor products holds as expected. projected cost may fall (as has happened with Second, the additional technology needed for computers) but much more often rises. The a central plant is electrical rather than me- maturation effect of costs during R&D has chanical or thermal, and is already proven at been particularly borne out in aerospace and the appropriate scale. energy technologies.14 15 Costs. –The cheapest acceptable technol- Although busbar cost estimates are useful in ogies available in any future time period will the research phase to identify cost sensitivities be the ones deployed, so cost is the most im- and indicate preferred research directions to portant — and most problematic —factor. Two reduce costs, they become crucial at the aspects of technology cost will be discussed.

The busbar cost is the cost at which truly com- “U S General Accounting office, “Need for Improved mercial versions of the various electric tech- Reporting and Cost Estimating on Major Unmanned Satellite nologies will produce power. The opportunity l’roject~, ” PSAD-75-190, 1975. “F W Merrow, S W Chapel, and C Worthing, “A Revtew of cost is the total cost of RD&D for a technology (-ost E ~tlmatlon in New Technologies Impllcatlons for Energy from inception through the construction of a I’recess Plants, ” R-2481-DOE, Rand Corp , 1979 124 ● Solar Power Satellites deployment phase. The DOE prepared cost all cases), and the assumption of baseload estimates for coal, light water reactors, coal operation for each technology. As noted gasification systems using combined cycle above, these numbers may be indicative but systems, LMFBR breeders, peaking terrestrial are Iimited in their use because the uncertainty PV plants, fusion and the SPS (fig. 28). ” The range represented by the range of costs means figure indicates the high and low ends of the different things for each different technology. range of estimates for each technology in Factors that are small contributors to the 2000. It shows that capital costs do indeed in- estimated costs may have uncertainties that crease with complexity, rising steadily for coal, are substantial (such as nuclear waste disposal LWR, LMFBR, fusion, and SPS systems. Costs costs) but are difficult to identify and measure. are also relatively high for the terrestrial PV. Finally, baseload operation is not necessarily Although it is an unlikely circumstance, the the most attractive operating mode for solar chart indicates that alI could cost the same in thermal and solar PV though it provides a basis 2000. for comparison.

OTA prepared estimates that considered RD&D Costs. –One of the most difficult these future electric technologies including fu- tasks in choosing the wisest course for RD&D is sion (but not combined cycles), in terms of to maintain the proper balance between the their busbar costs in 2010. The resuIts are given risks and the potential payoffs associated with in table 17, using common financial consid- a particular line of research. The goal is to erations, equal capacity factors (65 percent in minimize the risk and maximize the payoff. In energy research, the risk is associated with the “Program Assessment Report statement of findings, SPS Con- expenditure of RD&D funds for a project that cept and Evaluation Program, DOE/E R-0085, 1980 could conceivably fail. The hoped-for payoff is Figure 28.—Levelized Lifecycle Cost of Electricity cheap energy. The associated RD&D funds required to pursue some of the future electric options under consideration are so great that it is Iikely that not al I can be pursued at an optimum rate. By according priority to some, opportunities for payoffs from others will be foregone.

As the matrix of table 16 makes clear, SPS wiII have the highest front-end costs by a considerable margin, followed by fusion and the breeder. The solar thermal and solar PV systems will have lower RD&D costs, in the range of $0.5 biIIion to $2 billion.

The costs of the breeder will be large–in the range of $10 billion to $15 billion— assuming the United States does not change Levelized generation cost (1978 mills/kWh) the present policy of developing domestic rather than foreign technology. But this figure is nevertheless comparable to the front end costs of other centralized energy technologies. Cumulative RD&D for light water reactors, for instance, is estimated to have total led $10 billion. Fusion’s costs will be the same or

SOURCE: Program Assessment Report Statement of Findings, SPS Con- somewhat higher, estimated at $20 billion to cept and Evaluation Program, DOE/E R-0085, 1980. $30 billion, including a commercial prototype Ch. 6—SPS in Context ● 125

Table 17.—Summary Assessment

Prospective economic-cost Relative Commercial range a (1 980 $) environmental Engineering/ readiness Technology (mills per kWh) costs Scientific technical Commercial (year) Satellite power system ...... 80-440 Unknown Provenb Unproven — 2005-2015 Solar photovoltaic with storage 65-86 Negligible Proven Proven Unproven Late 1980’s Solar thermal with storage. . . . 62-89 Negligible Proven Proven ● Unproven Late 1980’s Breeder reactors ...... 58-73 Substantial Proven Proven Proven 2000 Fusion ...... 44-75C Moderate- Unproven — — ? substantial LWR-201O ...... 58 Moderate- Proven – Proven Proven Operational substantial LWR-1980 ...... 47 — — — — —

aPlant starting in 2010. bEnvironmental impact still unknown, other aspects generallY accepted.

CNote this range reflects differences between two studies’ estimates (footnotes 1 Cl and 11 On p 120). aMassive scale-up of known technologies. SOURCE: OTA working paper.

plant. Fusion and the breeder may thus com- tal impacts, and operating structure are similar pete with each other for R&D funds. to current LWR technology. As technologies used in the centralized mode, the solar tech- The costs of the SPS will be substantially nologies will not require different institutional higher than for any of the other options, at an attention than do any other peaking or inter- estimated figure of $40 biIIion to $100 bilIion. 7 mediate plant. As dispersed plants, they are The high number assumes all space develop- likely to be subject to a much different regula- ment and pIant investment costs are allocated tory regime’ 8 and utility structure that encom- to the SPS (see ch. 5), while the lower number passes a much broader technological scope assumes the total cost but allocates $60 bill ion than is now the case. to other space programs that could benefit from the same technical capability. SPS, however, because it is a space system requiring very high capital investment, would The SPS RD&D cost is so high that commit- likely involve an institutional structure very ment to it could foreclose fusion or the unlike those in use today in the utility industry breeder. As such, a decision at some point in (see ch. 9). The main point is that the utilities the future to commit to the SPS would be a are unlikely to want to invest directly in decision with potentially far-reaching con- satellites, or perhaps even rectennas. It will sequences. create far fewer regulatory and capital prob- In fact, the SPS is the first proposed energy lems for the utilities for them to buy power option whose RD&D costs enter the budgetary from a single SPS corporation and incorporate range that has previously been limited to very It directly into their grid. A national SPS high-technology, high-cost national defense monopoly would necessarily be federally, as programs such as the MX missile system. That welI as internationally regulated (see ch. 7). system, as proposed, will cost” $34 billion to National Security Risks. – Both of the nu- $50 billion. Thus, from a policy point of view, c I ear technologies u rider the SPS is qualitatively different from any consideration (breeders and fusion) can be used to generate other proposed long-range energy solution. weapons material and therefore they carry Institutional Impacts. — Neither fusion nor some risk of increasing nuclear weapons pro- fission requires much that is new institution- liferation. The terrestrial solar technologies ally because their size, health and environ men- —.—

“Office of Technology Assessmentr U.S. Congress, “Decentralized Electric Energy Generation Systems,” upcoming 170TA Workshop on Technical OptIons, December 1979 report, fal I 1981 126 • Solar Power Satellites

seem to have purely beneficial national securi- Figure 29. —Quantified Health Effects ty effects, however. They can be exported and used around the world for peaceful purposes. 77 Because they would be used in relatively small Operation and units, they would be much less vulnerable than 10.0 maintenance, public any larger unit and less of a military risk for a r Operation and country selling the technology. maintenance, occupational Construction, mfr. SPS would have indirect military potential, largely from the technology that would be developed for space transportation and space construction. However, the system itself would serve as a poor weapon. The question of vulnerability of an SPS system to nuclear or other attack is a different issue. On the whole it is Iit- tle more vulnerable than any of the larger terrestrial electricity options (see ch. 7). LWR CG/CC LMFBR CTPV SPS MCFusion Economic Risks of RD&D Failure.— In & cc

general, the risks of failure are tied directly to SOURCE Program Assessment Report Statement of Findings, SPS Concept the opportunity costs for the different central and Evaluation Program, DOE/ER-0085, 1980. electric technologies. Therefore, the risks are higher for fusion and SPS than for any of the SPS and fusion, most of the issues are in this others. However, the financial risks of failure category. The difficulty of quantifying issues may be mitigated if some of the RD&D costs for SPS and fusion is a function of the uncer- are recoverable for other uses. For example, tainties about the final configuration these the space spinoffs from developing the SPS technologies will take as well as the lack of ex- could be significant (an upgraded shuttle, perience with them upon which to base esti- space platform technology, an orbital transfer mates of fatalities. This is an area that needs vehicle technology, high powered microwave considerable further study, not only for SPS or laser transmission devices), which would but in every other comparative study of energy reduce the economic risks. Here, as in the technologies. The major needs are to put all strictly research phase of an SPS program, it is the data on as common a basis as possible and very important to be cognizant of other space to quantify risks where they are currently un- and energy programs that could benefit from quantified (see ch. 8 for a summary of SPS dollars spent on SPS research and vice versa. health and safety risks). Safety and Health Risks. –OTA pursued no Environmental Risks. –As with health and independent study of health and safety risks of safety risks, OTA attempted no independent the five technologies. This assessment has analysis and has relied on the comparative therefore relied on the work of Argonne Na- assessment study of Argonne National Labora- tional Laboratory that was funded by the SPS tory.20 Table 18 summarizes the most impor- office of DOE. ’9 The reader is referred to its tant environmental effects for each of the report for a comprehensive treatment of the technologies under study, plus coal. The nu- problem (see also app. D). The Argonne study clear technologies have been grouped together attempted to quantify risks in terms of the because their effects are common to all the number of fatalities that would occur per year nuclear technologies. for a specified plant output (see fig. 29). Some of the issues are unquantifiable, and for the ‘“L J H abegger, J R Gasper, and C D Brown, “Health and Saft’tV Pr~~llmlnary Comparative Assessment of the SPS and ‘(’G R Woodcock, “Solar Power Satellites ~nd the Evolution Other F nt’rgy Alternatlve~, ” DOE report No DOE/E R-0053, April of Space Technology, ” presented at A I AA Meeting, May 1980 1 98() Ch. 6—SPS in Context . 127

Table 18.—Major Environmental Risks

Coal Nuclear SPS Air pollution Catastrophic events Atmospheric changes Atmospheric changes Land use Bioeffects from microwaves,

(CO2, particulate) Thermal discharge waste lasers, reflected light Esthetic deterioration disposal Electromagnetic disturbance Land use Land use

SOURCE: Office of Technology Assessment

Other factors. – How well would SPS com- jor resemblance to terrestrial technologies is pete with other baseload electric tech- the fact that it produces electricity. However, nologies? This question can ultimately be perhaps more important is the fact that answered only in the context of overall de- breeders could play a significant role in sup- mand for electricity, considerations that are plying electricity 10 to 20 years before the SPS, taken up at the end of this chapter. However, if thus giving them an automatic competitive ad- demand for electricity is such that SPS may be vantage. needed to supply a portion of that demand, Although the fusion program has not yet then the competitive position of SPS vis-a-vis proven that it is possible to generate more the other technologies will depend primarily energy than is fed to the fusion process, the fu- on its being cost competitive, and presenting sion community is confident that the produc- comparable health or environmental hazards tion of electricity from fusion is a matter of to the other technologies. Other utility con- continued R&D. The costs are more uncertain cerns such as its reliability and rated capacity than for SPS. However, fusion has a strong factor have direct and obvious economic im- followlng inside and outside the fusion com- pacts that are subsumed in the condition of its munity. Furthermore, the utilities are already being cost competitive. It is too early to tell actively pursuing fusion studies. Therefore, if whether SPS can compete effectively. What is fusion’s costs turn out to be competitive with clear, however, is that factors beyond the SPS, it too may be chosen over SPS because it scope of control of an SPS program may deter- has a strong following and because beyond the mine more effectively whether SPS is com- first wall, it is similar to other nuclear options petitive than the important concerns over in the way in which it generates electricity. costs or health and environmental effects. The However, it may not be capable of making a effects of reduced coal useage are examined significant impact on the supply of electricity below. However, before the United States untiI welI after SPS, i.e., not until 2030 or later. needs to decide whether it is prudent to continue or expand coal burning (c 2000), it must Because several proposed versions of the make a decision about the use of breeder reac- SPS are designed to use PV cells, a terrestrial tors (c 1990). If we institute a strong breeder PV system constitutes an obvious comparison program, then SPS is less likely to be needed to the SPS. The satellite or SOLARES ground than otherwise, simply because breeders are site would receive continuous sunlight. A ter- apparently cheaper to build and operate than restrial system, however, receives constantly the SPS. They have the further competitive ad- varying sunlight. Table 19 compares the peak vantage that they strongly resemble LWRS, and total annual insolation in space, at a both in operating characteristics and in health, SOLARES ground station and in Boston and safety and environmental impacts.21 Thus, util- Phoenix for an optimally tilted flat-plate, non- ities are more Iikely to purchase breeders than tracking solar collector. Therefore, a terrestrial to take on a brand new technology whose ma- PV in Phoenix the size of a reference system rectenna would, in theory, be capable of pro- “E. P Levine, et al , “Comparative Assessment of Environmen- tal Welfare Effects of the Satellite Power Sytem and Other ducing as much electricity on a yearly basis as Energy Alternatives, ” DOE report No DOE/E R-0055, April 1980 the reference satellite. However, the output of 128 Ž Solar Power Satellites

Table 19.—Terrestrial and Space Insolation Compared

Average annual Area needed to produce 1,000 MW Peak insolation (per insolation (per (per continuous output on Earth square meter) square meter) (17-percent efficiency cells) Space...... 1.3 kW 11,800 kWh 10 km2 SOLARES GND Station (29° latitude)...... 1.3 kW 9,734 kWh 6 km2 Boston...... 0.8 kW 1,430 kWh 44 km2 Phoenix ...... 1.0 kW 2,410 kWh 26 km2 Equivalent rectenna area for reference system—35° latitude...... — — 28 km2 —. SOURCE: Office of Technology Assessment,

such a central terrestrial system would be sub- Dispersed modes of generating electricity ject to short-term and seasonal variations in are first and foremost attractive in remote output due to fluctuations in insolation regions where the electricity grid has not yet brought out by cloud cover. This effect is il- penetrated. It is in these areas where windmills lustrated in table 20 for the Boston and and PV, with storage, are now being installed Phoenix areas. The daily insolation for the even though their cost is high relative to the month of December is 28-percent less than for price of grid-supplied electricity. the average month, resulting in 28- percent less As experience with these technologies PV output for the same sized array. Phoenix, grows, and their price decreases due to deeper by contrast, experiences average insolation market penetration and increased commensu- values only 14 percent lower than the average rate production, they are likely to penetrate in July, its month of lowest insolation. areas that are now served by the utilities. Such a shift will be aided by the Public Utilities Decentralized Electrical Generation Regulatory Policies Act of 1978 (PURPA) that Although technologies that are capable of requires utilities to purchase electricity from producing electricity in a dispersed mode may renewable-based powerplants at their avoided not be direct competitors of centralized cost of power. To date, State regulatory com- technologies, they will compete for a percent- missions have established prices that are equal age share of overall electricity supply in this to, or higher than, the retail price of electricity. country and the world. In 1977, the residential If this practice should continue into the mid- sector of the electrical market constituted 36 1980’s, onsite electrical generating systems will percent of this Nation’s demand for electricity. not only provide energy for their owner’s use, If a significant portion of this demand as well but will become income generators as well. as part of the demand for commercial and in- This shift will be further aided by the attrac- dustrial consumption can be met by dispersed tiveness of modular units that allow a home- technologies such as solar PV, wind, and owner or community to become relatively self- biomass at costs that are competitive with cen- reliant and independent of large-scale generat- tralized electricity, then the demand for cen- ing systems over which they have little control. trally produced electricity will drop. Low de- Additionally, onsite systems can be erected mand for centrally produced electricity will in rapidly and incrementally, allowing a close turn reduce the need for new, large-scale match of supply to local demand. Under such generating technologies and place them in a conditions, it can be expected that there would poor competitive position with respect to be a rapid increase in demand for small-scale proven technologies. Thus, it is of considerable systems. interest to investigate the role that dispersed electrical technologies may play in the Na- The role of dispersed electrical generating tion’s energy future. technology in the Nation’s electrical supply is Ch. 6—SPS in Context ● 129

Table 20.—Terrestrial Insolation at Different Latitudes and Climates Boston: Latitude 42.2

Jan. Feb. Mar. Apr. May June - July Aug. Sept. Oct. Nov. Dec. kWh/m 2 3.4 3.7 4.1 4.0 4.4 4.3 - 4.6 4.4 4.4 4.1 3.0 2.8 kWh/m2/month 104 104 126 119 135 129 142 137 131 126 90 85

Total insolation per year 1,430 kWh/m2 Average daily insolation: 3.9 kWh/m2

Phoenix: Latitude 33.3

Jan. Feb. Mar. Apr. May June - July Aug. Sept. Oct. Nov. Dec. kWh/m2/day 6.0 7.0 7.4 7.5 6.6 6.2 5.7 6.2 7.0 7.3 6.7 6.0 kWh/m 2/month 184 195 228 225 204 186 178 185 218 227 200 185 — Total insolation per year 2,414 kWh/m2 Average daily insolation: 6.6 kWh/m2

SOURCE: Solar Photovoltaics: Applications Seminar, Planning Research Co

the subject of another OTA study that will nected to the utility grid or stand alone. discuss the full array of dispersed electrical Meeting this cost goal is important for the SPS, technologies: wind, PV, and biomass. How which in the reference design, is highly sen- ever, because much of the technology for con- sitive to PV array costs (34 percent of satellite structing space-rated solar cells will be ap- costs). plicable to terrestrial applications and vice versa, this report explores the possible role of The total penetration of PV and other decen- dispersed PV systems in filling part of this tralized energy technologies into the residen- country’s electrical needs in the time frame of tial, commercial, and industrial sectors of the the SPS. energy economy will depend on a number of Dispersed Photovoltaic Systems. —The most interrelated factors in addition to cost. The important single characteristic that makes PV following summary indicates the most impor- of considerable interest for dispersed uses is tant ones. their relative insensitivity to economies of scale for generating electricity because PV are ● Average Available Sunlight. –The best modular, allowing considerable flexibility in areas for dispersed PV are the same ones their location. Economies of scale are very im- where centralized applications are most portant in their production, however. The pres- plausible, i.e., in desert climates such as ent high cost of PV (about $7/peak watt) is the Southwestern United States. However, largely due to a very small production capaci- the variation of regional average insola- ty. About 4.5 MW (peak) of terrestrial capacity tion across the continental United States were produced globally in 1979, by only a is less than a factor of two. Changes from dozen manufacturers. Demand exceeds sup- year to year are considerably less. Both ef- ply, however, even at $7/peak watt and thus fects are smaller than variations in energy the market will surely expand, especially consumption and price patterns. Thus, as new manufacturing techniques allowing regional or annual insolation variations cheaper PV are developed. All indications are are not likely to be a strong determinant that continued reduction in price in line with of PV penetration. This will be even more DOE cost goals will accelerate the demand for true in areas where biomass and wind PV cells for all applications and in particular systems can work in complementary for dispersed systems that are either con- fashion with PVs. 130 ● Solar Power Satellites

● Storage. – Advances in storage technology they could have the opposite effect on the could have a significant effect on the mar- use of PVs. ket penetration of PV systems, particular- ● Cost of Photovoltaics. – Single-crystal ly for remote and stand-alone applica- silicon cells are highly energy intensive. tions. It is generally agreed, however, that Thus, the energy cost of producing them is low-priced storage, if it is ever developed, high, and if energy prices increase, the is a decade or two away. cost of the cells will be higher than the ● The Use of Centralized Photovoltaic Sys- DOE goals. New production techniques tems. — Using PV for peaking or inter- for amorphous silicon or other materials, mediate generating capacity will enhance however, may lead to less energy inten- the development of low-priced PV cells sive cells, and the problem could be and the auxillary equipment (mounting avoided. panels, inverters, etc.) and speed the in- ● Reliability y. –One of the major reasons for troduction of dispersed PV systems to preferring centralized power generation is marginal areas (i. e., areas where the cen- the high reliability of electrical service. trally generated electricity is cheaper than Dispersed systems must be reliable in onsite generation). order to capture a significant portion of ● Conservation. –Conservation has already the electricity market. The PV themselves resulted in important reductions in per- are extremely reliable. However, the asso- capita energy use. In the Washington, ciated equipment is subject to a higher D. C., area for example, use of electricity is failure rate. Market penetration will increasing by only 1.4 percent a year,22 a therefore depend on a highly reliable sharp contrast to the 7 percent yearly in- product and effective, timely service to crease in consumption that was common repair failures. in the mid-1 970’s. Continued price in- ● Institutional Effects. – PURPA regulations creases for energy will increase the desire wiII enhance the use of dispersed-systems. to conserve energy and make the total If these regulations are retained and if needs of a residence, for instance, much they are carried out effectively on the less. The Virginia Electric Power Co., for local level, then they will be effective in example, reports that in its service area speeding the introduction of dispersed all-electric homes, used about 24 MWhr/yr electrical capacity. However, a number of in the mid-1 970’s, but consumed only 19 negative effects (e. g., low reliability, high MWhr for 1979,23 a 20-percent drop. De- costs, etc.), could cause such regulations creases in total consumption make it to be repealed if they are found to work more likely that PV systems can be sized inefficientIy. to meet the needs of the residential sec- In summary, it can be said that the future of tor < dispersed electric systems, and PV in par- ● Other Dispersed Sources of Electrical ticular, is subject to considerable uncertainty. Power. –The acceptance of wind and bio- If cost goals are met, and the effect of the mass for dispersed electrical generation, other factors is positive overall, then dispersed or as substitutes for electricity, may en- electrical systems could make a significant hance the desire for photovoltaics as indi- contribution especially in a future in which the viduals and the utilities become accus- demand for electricity is relatively low. As tomed to working with dispersed sources. table 21 illustrates, the cost per kilowatt-hour However, if other sources failed to make a for grid-connected PV systems, though subject significant impact because they were ex- to considerable uncertainty, is competitive pensive or because they didn’t work well, with baseload systems. By combining several different kinds of dispersed sources of elec-

?>wfa5h;ngton Post, Mar 25, 1981, P D-9 tricity (e.g., wind, PV, and biomass), the pros- “Washington Post, June 23,1980, p B-1 pects for dispersed PV sales becomes even Ch. 6—SPS in Context ● 131

Table 21.–Costs of Onsite Photovoltaics (1980¢/kWh)

Household Industry Without storage With storage* Without storage With storage* Boston Phoenix Boston Phoenix Boston Phoenix Boston Phoenix Roof replacement...... 3.0¢ 1.8¢ 9.0¢ 7.O¢ — — — — Flat on roof ...... 3.9¢ 2.3¢ 9.9¢ 7.6¢ — — — — Columns on roof or ground ...... 8.3¢ 4.9¢ 14.7¢ 10.4¢ 8.O¢ 4.7¢ 18.9¢ 12.9¢

NOTE: These costs were developed assuming photovoltaic arrays costing $35/m2 and 17-percent efficiency in space (18 percent on ground). Further details of the assumed systems can be found in app. B. ● Assumed a 80-percent capacity backup generator, SOURCE: Office of Technology Assessment.

stronger than when used alone. As in the case tricity demand scenarios for 2030. The lowest of the baseload technologies, these figures assumes no change from our present end-use must be seen as indicative of the range of costs demand for electricity, the highest uses the that may be attained and should not be used as 1979 Energy Information Administration (E IA) a basis for comparison at this time. Con- high projection for 2020 extrapolated to 2030, siderable development wilI be needed to deter- and the mid-level is halfway between. These mine whether the various cost goals can be futures were chosen as an exercise to illustrate met. the way various technologies might be used and the constraints placed on this selection. Implications OTA does not treat these demand levels as forecasts of what will occur, but as a plausible Introduction range of future end-use demand. The discussions just completed illustrate that the future of the SPS, assuming it can be The extremes of the three scenarios are developed technically, depends on a variety of characterized by zero growth in electricity de- factors. These include the future demand for mand for the low scenario, and an average electricity and how SPS compares with other growth of 2.8 percent per year for the high supply technologies. There are two questions scenario from 1980 to 2030. The growth in the to be answered: 1) is the SPS necessary at all? high scenario is not steady, however, but starts 2) if so, when do we need it? The section on de- at 4.1 percent in the 1980-95 time period, and mand showed that future electricity needs are declines to 1.9 percent by the end of the sce- highly uncertain and are dependent on techno- nario in 2030. logical developments that can profoundly influence the costs of various end use technol- The low scenario represents a conservation- ogies. The section on supply contained discus- oriented energy strategy, in which the in- sion of several technologies that would com- creases in industrial output and residential and pete, partially or completely, with the SPS to commercial space are offset by improved effi- supply electricity for the long term. The sec- ciency of electricity use for industrial proc- tion gave criteria for choosing between these esses and drives, and residential and commer- technologies and the range of uncertainty cial heating, air conditioning, lighting, and ap- about their potential success. From the discus- pliances. The end-use electricity level in the sion it is clear that a variety of factors beyond low scenario, taken from the CONAES sce- purely technical success will determine which nario A, assumed electricity demand at a con- supply technology(ies) wiII emerge. stant level of 7.4 Quads for 1980 to 2010, and To see this more clearly, OTA chose three extrapolated the same constant level to 2030. hypothetical U.S. energy futures in order to ex- That level is very close to the actual end-use amine possible future supply mixes. They were electrical consumption in 1979 which was 7.6 chosen to span a wide range of possible elec- Quads. The total primary energy consumption 132 ● Solar Power Satellites

in the CONAES scenario A is 74 Quads, com- were chosen to illustrate the way various tech- pared to actual use in 1979 of 78.9 Quads.24 nologies might be used and the constraints that might be placed on their selection. The high scenario represents a major expansion of the use of electricity in all sectors. The To characterize the mix of supply technol- scenario is taken from the E 1A Series C projec- ogies possible under these scenarios, a number tion from the Long-Term Energy Analysis Pro- of questions was addressed. Among these gram. The total primary energy use in this questions were the numbers and kinds of tech- scenario is 169 Quads. The scenario projects a nologies that would contribute to the supply major shift in residential fuel use, with elec- mix under the various scenarios, the maximum tricity supplying 60 percent of all residential reasonable SPS contribution under each sce- needs and 55 percent of residential heating. nario, the most likely technologies to replace (Water and space heating alone are projected SPS were it not deployed, and the relative im- at 8 Quads end-use electricity in 2020.) Elec- plementation rates of the various technologies tricity is expected to provide 70 percent of the under different demand conditions. The exer- commercial energy demand in 2020. In this cise carried the simplifying assumption that project ion, EIA forecasts that the industrial one technology could be substituted for sector wilI grow faster than any other sector, another These questions cannot be answered and that industrial use of electricity will triple precisely, but their discussion leads to in- or quadruple by 2020. Total energy use in the teresting insights into the potential role of SPS. industrial sector in the scenario is 63 Quads in 2020. Electricity’s share of the industrial Low-Demand Future energy sector rises from 11 to 20 percent. The For this case, end-use energy demand for dominant supply technologies in the scenario electricity is selected to be 7.5 Quads (today’s are coal and nuclear, with coal providing 60 level). A zero electric growth future is likely to percent, nuclear 33 percent, and hydro and be the result of substantial conservation – other renewable the remainder. The E 1A sce- probably resulting from high energy prices — nario was extrapolated to 2030, using the same and the failure to develop end-use technol- electric growth rate as assumed in 2010 to ogies that use electricity at a lower net cost 2020, namely 1.9 percent. According to the ex- than technologies using liquid or gaseous fuels trapolation of this scenario, the total energy and direct solar. The principal feature of this use in 2030 is 196 quads and the total electri- future is that electricity demand can be satis- city use is 30.2 Quads (end use). fied without SPS, fusion or breeder reactors. The middle scenario is chosen to be the mid- The supply potential of coal, hydro, ground point between the high and low scenarios at based solar (including wind) and conventional each of the decades projected. The end-use nuclear would be more than sufficient to meet figures for each of these three scenarios are demand Even if coal were to be phased out given in table 22. due to negative findings about the CO, buildup, its share could probably be absorbed by OTA does not suggest these demand levels other sources. Zero growth in electricity de- as forecasts of what will occur. These futures mand gives the nation considerable time for

24[ner~y jn Trans;tjon, OP c I t developing new technologies. In this situation utilities would only need to Table 22.—Range of Energy Demand in 2030 replace retiring plants. Therefore they would have considerable latitude in choosing tech- End-use electrical Primary total Scenario (Quads) energy (Quads) nologies. Further, a zero growth rate would not High ...... 30.2 196 favor large plants because they would add too Mid ...... 18.8 135 much capacity at one time. Therefore, small- Low ...... 7.4 74 scale, dispersed technologies may play a major SOURCE: Office of Technology Assessment. role in this future. If any of the new tech- Ch. 6—SPS in Context ● 133

nologies under discussion are introduced they 2030, this mix may be insufficient. Yearly coal will have to appear in relatively small in- production could probably not be expanded crements in order to maintain system reliabili- too much beyond this (tripled) level without ty. For example, one could expect SPS to pro- straining other sectors of the economy, and by vide no more than 1 to 2 Quads at any given 2030 the Nation may be near its uranium re- time to the 7 to 8 Quad total. This would act source limits. Therefore, to ensure supply strongly against an SPS the size of the ref- beyond 2030 and to replace retiring nuclear erence system since it would only require 7 to plants, some level of new, centralized tech- 15 units of 5,000 MW at a 90-percent capacity nologies would probably be needed. factor to supply this much energy. Therefore deployment of any SPS would depend on an in- If coal and conventional nuclear remain ac- ternational demand for electricity and/or the ceptable, it is not likely that all three of the development of much smaller units than the major centralized technologies under develop- reference system (perhaps on the order of 500 ment would be needed. The contribution they MW). A similar argument could be made about could make by 2030 would be small because of fusion and breeder reactors, although current the time needed to bring them on line and the development plans show the size of eventual fact that they would be starting from a zero commercial plants to be 1,000 MW or less. base sometime near 2010. A 10-percent contribution to 20 Quads would require anywhere In summary, a scenario that shows little or from 60,000 to 100,000 GW, depending on no increase in electricity demand for the next capacity factor. Unlike the low demand future, several decades does not appear to be attrac- this would allow SPS units of up to 5,000-MW tive for accelerated SPS development, particu- size to be added if continued growth past 2030 larly of the reference system. At the same time, is expected. A 2 percent per year growth rate development of other central, baseload supply means about 0.4 Quad/yr added at that time. options ultimately competing with SPS could This could be supplied by three SPS plants per also be slowed. The choice among these, if year at the reference design size, in addition to needed at all, would primarily depend on baseload units to replace retired pIants. This is which ones could most economically be de- stiII a small enough increment that smaller SPS veloped in smaller sizes. pIants appear to have an advantage. In addition, this demand increment is still not too Middle Demand Future large to rule out its being met by onsite solar, wind, and centralized solar. All have much In this case net electricity demand reaches lower energy densities than fusion or breeders, about 20 Quads in 2030 representing about a 2- however, and eventually their contribution will percent growth rate per year that is close to be limited by available area. About 25 m2 are that which the Nation is now experiencing. required to supply a continuous kilowatt of Although this is about 2.5 times current elec- solar electricity assuming PV conversion effi- tric energy demand, it too could be met with- ciencies of 20 percent. The entire 0.4 Quad out using the SPS, fusion or the breeder reac- could be supplied by about 125 mi2, not an tor. For example if two-thirds of the 20 Quads unreasonable area. were produced by coal, it would require a tri- pling of present yearly production, which is If coal is not acceptable because of C02 within the Nation’s capability. Current esti- then there will have to be a substantially larger mates of domestic uranium reserves are suffi- contribution by the newer technologies. In this cient to supply another 6 Quads in 2030. In ad- case it is plausible that all three, plus substan- dition, a major contribution from terrestrial tial ground based solar, would be needed. solar (wind, onsite PV) can be expected to help Such a replacement could be achieved with meet increased intermediate and peak load these new technologies but it would be a demands that coincide with solar peaks (space sizable effort. If coal supplied just half of the heating and cooling). If growth continues past electricity in the case discussed above, about 134 ● Solar Power Satellites

10 Quads of new electric energy would have to and breeders. Breeders are likely to supply the be found, requiring 300 to 500 GW. If new bulk of this by 2030, provided they are accept- plants were on the order of 1,000 MW in size, a able, since they are the closest to commercial construction rate of 15 to 25 per year would be readiness. Even so, as much as 200 GW of SPS needed assuming they were first available in could be needed by 2030. The SPS develop- 2010. Under this future of constrained coal, ment would have to be accelerated if it is to then, there would appear to be sufficient de- meet a goal like this. The same holds true for mand for al I technologies to be introduced at a fusion, which could also be required to supply rate that would pay for their development in a around 100 GW by 2030. reasonable period. Also, it is not Iikely that any one technology wouId be relied upon to supply The mix of technologies will be determined the entire 10 Quads at the end of this 20 year substantially by constraints such as environ- phasing-in period. An even three-way split, for mental concerns, capital, land and water avail- example, would mean that SPS would supply ability, materials Iimitations and labor require- about 100 to 150 GW by 2030. ments. For example, limited water would favor SPS and ground-based solar PV. Limited cap- High-Demand Scenario ital, however, would favor the least capital- intensive technologies such as coal and act This future assumes a final demand for elec- against the SPS. In any event, these constraints tricity of 30 Quads (about four times the cur- will be very important at this demand level rent level), meaning a growth rate of about 2.8 because of the large number of powerplants percent per year. At that rate, about 0.8 needed Quad/yr would be added in 2030. If one assumes an increase in net conversion effi- If coal must be phased down or eliminated ciency from today’s 29 to about 35 percent and then even larger demands will be put on the an increase in capacity factor from 42 to 55 new technologies. For example, if coal and percent, then this total demand could be met conventional nuclear couId only meet one- by an installed generating capacity about third of the demand, an additional 600 GW of three times today’s figure. Efficiency and capacity would be needed. In this case it is capacity factor will almost certainly have to probable that an all-out breeder program increase if a 30-Quad demand is to be met. would be needed. This should not affect the Total system capacity would be in the range of SPS– in fact, more satellites may be needed– 1,200 to 2,400 GW (1,800 GW at 55-percent but it could actually reduce fusion’s contribu- capacity factor). tion since it is a competing nuclear technology. The terrestrial, onsite solar contribution To be able to supply this much electric will have to be large in either case but is very energy, all technologies would probably be unlikely to be able to supply even one-half of needed. Further, larger plants are likely since a the 30 Quads. Even 20 percent of the demand demand increment of 0.8 Quad/yr would re- would require a very large deployment of PV quire about 40,000 to 50,000 MW of new ca- systems — nearly 400 GW of dispersed gen- pacity per year. Therefore, addition of plants erating capacity. ranging from 1,000 to 5,000 MW would not cause any significant short- or long-run over- Conclusion capacity problems. Because of the large amount of capacity needed, conventional nu- The size of future electric demand will be clear and coal will probably be able to supply the major determinant in the amount of SPS only about two-thirds of the total (i. e., about capacity installed, assuming successful de- 1,200 GW) before they reach the limits dis- velopment and competitive price. Table 23 cussed above. Thus, about 600 GW must be shows estimates of the upper range of SPS supplied by hydro, ground based solar, geo- capacity available for each future for the case thermal, and some combination of SPS, fusion of fulI coal development and coal phaseout. Ch. 6—SPS in Context Ž 135

Table 23.–Upper Range of SPS Use (in GW) struction schedule. The mid scenario, however, gives somewhat ambiguous results, although Future (Quads) With coal Without coal the smaller size SPS systems appear generally 7.5 0 0-30 20.0 0-60 100-200 to be more desirable. 30.0 100-200 100-200 For the first two scenarios it is unlikely that SOURCE: Office of Technology Assessment alI three major, centralized supply technologies will be needed simultaneously, even if coal cannot be used. Onsite, dispersed solar In addition to determining the upper range will be able to make up a larger percentage of of the contribution of SPS the demand level the needed capacity and could eliminate the and rate of growth will also determine the need for any new centralized technology in the preferred unit size. For the low scenario, low demand case. In all cases, coal can be the smaller plants would be preferred since over- dominant source and continue in that role for capacity problems caused by adding too much several years past 2030. Finally, as the demand at once would probably more than offset gains for electricity increases, decisions about ca- made by any economy of scale. For the upper pacity mix will become more and more de- future, however, for even the largest SPS pro- pendent on physical and labor constraints be- posed plant size, it is unlikely that too much cause of the sheer size of the capacity re- can be added at once for any reasonable con- quirements.

THE EFFECTS OF SPS ON CIVILIAN SPACE POLICY AND PROGRAMS

The effects of SPS development on the U.S. with minor modification and changes of em- civilian space program would be great, though phasis. The 1958 Act states that “activities in their precise type and magnitude would de- space should be devoted to peaceful purposes pend on the kind of SPS built, the overall for the benefit of all mankind,” to promote the speed of the development program and the “general welfare and security of the United status of space capabiIities at the time. An SPS States “ The Act specifies that civilian ac- program would stimulate more rapid develop- tivities shall be directed by NASA, and mili- ment of space transportation, large-structure tary/defense operations by the Department of assembly and manned-mission capabilities, Defense. The specific aims of the space pro- and automated operations. SPS development gram include: expansion of knowledge, im- would also have a bearing on national space provement of space transportation, “the pres- policy and institutional structures, both Gov- ervation of the role of the United States as a ernment and private sector. The following leader in aeronautical and space sciences,” discussion will examine four areas: 1) space and cooperation with other nations. NASA was policy, 2) current and future space projects, 3) established to “plan, direct and conduct institutional structures, and 4) indirect effects aeronautical and space activities. ”25 and “spin offs.” These general goals and this framework have been reaffirmed subsequently, most Space Policy recently in the “Directive on National Space The Nation’s space policy is a reflection of Policy” and the “White House Fact Sheet on broad national goals. The principles guiding — the U.S. civilian program were first enunciated ‘5 ’’Natlonal Aeronautics and Space Act of 1958, as Amended, ” in Space Law, Selected Basic flocuments, Senate Committee on in the 1958 National Aeronautics and Space Commer[ e, Science, and Transportation; U.S. Government Print- Act, and have been periodically reaffirmed ing Of flee, 1978; pp 499-503 136 ● Solar Power Satellites

U.S. Civil Space Policy,” both issued in 1978. In further the economic goals that have been em- these documents the Carter administration phasized in recent policy proclamations. committed the United States to increase scien- The political end of U.S. preeminence in tific knowledge, develop useful commercial space, though no longer stressed as strongly as and Government applications of space tech- during the Apollo program, would also be nology, and “maintain United States leader- served by commitment to an SPS. (This ship in space technology. ” Establishing and assumes that the project would be successful; maintaining satisfactory relations between the failure of such a high-visibility effort could be civil and military programs was recognized as extremely damaging to U.S. prestige. Interna- and the National Security a priority issue, tional cooperation might tend to mitigate this Council was charged with providing coordina- danger. ) tion for all Federal agencies involved in space. Cooperation with other nations, including joint The SPS program would not be focused on programs and the development of a stable increasing basic scientific knowledge, but legal regime allowing all nations to use outer- much of the research and experimentation re- space for peaceful purposes, were emphasized quired would provide some scientific gains; in as important goals. The investment and direct addition, the infrastructure for SPS (e. g., plat- participation of the private sector in space ac- forms, transportation vehicles) could be used tivities was addressed in the context of remote- for a multitude of scientific projects in space. sensing systems. NASA’s responsibilities for There is some danger, though, that focusing the operation, as opposed to research, de- the national space program on such a major velopment, and testing, of applications sys- applications project as SPS would divert re- tems have yet to be clarified.26 sources and attention, at least temporarily, from scientific missions. The U.S. civil space program can thus be said to have an ongoing set of policy goals: The effects of SPS on the U.S. policy framework will depend on how it is financed and ● scientific — increasing knowledge, managed. Civil-military relations could be ● political — maintaining U.S. preeminence, altered. Although the SPS is not technically and suited to be used as a weapons system, much ● economic–developing useful commer- of SPS technology and infrastructure, especial applications. cialIy the transportation vehicles, would have It also has a continuing policy framework: military uses (see ch. 4). Furthermore, it is unlikely that a project with the scope and im- ● separation of civil and military programs pact of SPS could be approved by Congress (with various mechanisms for coordinat- without at least the tacit consent of the De- ing different efforts), partment of Defense (DOD). In the foreseeable ● cooperation with foreign countries and future, DOD requirements for aerospace ex- agencies, and pertise and facilities will be great, and SPS may ● separation of NASA R&D and prototype be seen as a competitor for scarce resources development programs from commercial unless direct defense benefits can be realized. applications (an unclear relationship). Although an SPS program would not be run by Would an SPS program alter the basic thrust the military, it might be necessary for the civil of U.S. policy? I n terms of goals, an SPS pro- and miIitary sectors to be more closely coor- gram would be primarily an applications effort dinated than has previously been the case. for commercial purposes, and hence would Foreign cooperation and joint ventures might be encouraged not only by the desire to

26’’ Description of a Presidential Directive on National Space improve international relations but by more Policy, j une 20, 1978, ” and “White House Fact Sheet, U.S. Civil direct economic considerations. (see ch. 7). Space Policy, Oct 11, 1978,” in Space law, pp 558-564. These considerations would be strong enough Ch. 6—SPS in Context • 137

to provide for a greater degree of shared number of smaller scale operations and scien- responsibility than in any equivalent U.S. pro- tific missions centered around use of the Shut- gram to date, unless U.S. military involvement tle and other components of the Space Trans- proves an insuperable obstacle. International portation System (STS). The lack of a single, participation might be such that the project clear, overriding project goal for the civilian could no longer be run as a U.S. venture with space program has been criticized for squan- limited foreign cooperation, but would be- dering NASA and contractor capabilities, and come a truly multinational effort with no leaving the United States without a visionary dominant U.S. role. and profitable use for the new transportation capabilities under development. This problem The relation between public and private will undoubtedly be addressed during the participants would be a major issue in any SPS 1980’s, but jurisdictional and philosophical program. Policy in this area has not been clear- differences, as well as budgetary constraints, Iy established, though there is precedent for may make consensus difficuIt to achieve. detaching applications projects, such as satellite communications and Landsat, from NASA For the next 5 years, NASA plans to concen- after development is completed. NASA has trate on a number of areas: those most directly conducted all U.S. civilian launches on a relevant to SPS include: reimbursable basis; it is unclear what would 1. Transportation and Orbital Operations: happen if private firms wished to build and/or Transportation efforts will concentrate on launch their own vehicles, as has been sug- meeting shuttle schedules but also in- gested for the shuttle. If, as is presently the clude other elements of STS: the inertial case, a Federal SPS program were managed by upper stage, for placing payloads in geo- DOE or some other agency besides NASA, synchronous orbit (CEO) (under devel- NASA might be responsible for only a limited opment by the Air Force); Spacelab, for part of SPS development and NASA restric- manned and unmanned experimentation tions and policies might not apply. (joint program with ESA); development of orbital transfer vehicles such as an elec- Current and Projected Space Projects tric orbit transfer vehicle (EOTV); systems to handle payloads outside of the Shuttle; SPS would be strongly affected by current and free-flying platforms. Each of these space programs and capabilities, and in turn programs will be important for improving might also determine what many of those programs would be. However, since an SPS devel- our capability to move and work in space, and hence directly relevant to SPS. The opment decision is unlikely to be made before key element is the Shuttle, which must 1990, and may not be possible until 2000, (see work and work well if these projects are to ch. 4), SPS will not shape NASA projects conducted during the next decade (though it may proceed during the 1980’s. Delays in Shut- affect long-range planning). tle operations, or in building additional orbiters, will not only retard these projects Historically, NASA has devoted the major but also might prevent SPS-specific re- portion of its resources to a single major proj- search flights as envisioned in one of the ect, first the Apollo lunar-landing program, policy Options from taking place in the and then the Space Shuttle. However, there are late 1980’s (see ch. 4). currently no plans for a similar “centerpiece” 2 Immediate Applications: In this area, project to follow the Shuttle; the White House space processing experiments to be con- Fact Sheet asserted explicitly that: “it is ducted on Spacelab could be important in neither feasible nor necessary at this time to determining the proper kinds of materials commit the United States to a high-challenge for SPS construction, as well as prospects space engineering initiative comparable to for direct processing of raw materials in Apollo.” Instead, present plans call for a orbit. Communications and remote-se ns-

83-316 0 - 81 - 10 138 ● Solar Power Satellites

ing development will involve work with tion, and operations, by the end of the 1980’s; microwave transmission, lasers, and mir- and 4) a permanent facility in GEO, eventually ror systems, as well as detailed studies of manned, by the late 1990’s. Meeting goals the upper atmosphere,27 which will be wouId involve: vital in determining the environmental ef- • augmenting the Shuttle’s thrust, perhaps fects of launch effIuents and energy trans- via a Iiquid booster; mission beams. ● developing EOTVs, such as the low-thrust 3. Solar Radiation:The Solar Maximum Mis- ion-propelled Solar Electric Propulsion sion (launched February 1980) and the up- System (SEPS) for service to geosynchro- coming International Solar Polar Mission, nous orbit; scheduled for 1983, will study solar radia- ● equipping the Shuttle and its modules tion and its effects on the near-Earth with a 25-kW add-on electrical power sys- space environment. Such information tem; and could be important in designing SPS solar ● carrying-on a ground and space-based ef- cells and in adding to our knowledge of fort to fabricate and assemble precision the effects of radiation on SPS workers: structures in orbit .29 ionizing radiation in CEO is a potentially serious obstacle to human effectiveness All of these projects could have direct bear- and could be decisive in determining the ing on SPS and on any future decision to pro- optimal “mix” between automated and ceed with SPS development. Some of the human-controlled operations. longer term aims, such as SEPs, might overlap 4 Humans in Space: The studies of Shuttle with an SPS development program, that would crew performance as well as specific provide a strong impetus for their completion. Spacelab experiments will provide a basis NASA is not the only body with plans for for determining the long-term effects of space. DOD goals, though largely classified, weightlessness and cramped quarters, and include large platforms, orbital microwave for designing appropriate equipment to radars, and space-based lasers. DOD require- improve manned performance. 28 ments couId drive NASA projects such as Shut- The above projects are already underway tle thrust augmentation, or lead to separate and are those for which funding or explicit development of SPS-useful equipment. planning are in place. NASA has also outlined Other long-range projects have been sug- other, longer term plans that would be impor- gested by many individuals and organizations, tant to SPS. NASA’s Office of Space Transpor- in and out of government. In the transporta- tation Systems’ long-term goals are predicated tion area, these include very large fully on the assumption that “the growth of U.S. reuseable launchers; laser-propulsion; 30 Iight- civilian space programs in the 1990’s will prob- sails, to power low-acceleration transfer ably continue to be moderate and evolu- vehicles or deep-space missions; 31 and mass- tionary, rather than rapid or ‘Apollo-like,’ “ drivers to lift material off the lunar surface, or and that “space projects will increasingly have as a solar-powered propulsion system for to demonstrate significant economic return or space vehicles.32 Other than the building of perform essential services to obtain approval.” full-scale permanent colonies, SPS is the The specific goals are: 1 ) routine operation of largest space project proposed to date, in the STS by the mid-1 980’s; 2) routine operation of unmanned large low-Earth orbit (LEO) plat- 2’1 b[d Pp 190-205 forms by the mid-1980’s; 3) a permanent (l ‘ A Hertz berg, K Sun, W Jones, “Laser Aircraft, Astronautics manned facility in LEO for research, construc- and Aeronautics, March 1979 p 41 “K Eric Drexler, “Spinoffs To and From SPS Technology: A Preliminary Assessment,” OTA Working Paper, June 1980, p. 9 Z7N~t10nal Aeronautics and space Adm Inistration, ~AsA f’ro- ‘2(, O’NeIll, G Driggers, B. 0’Leary, “New Routes to Man- gram P/an, F;sca/ Years 1987 Through 7985, 1980, p 107 ufacturing In Space, ” Astronautics and Aeronautics, October *a Ibid, pp 3-5 1980 Pp 4651 Ch. 6—SPS in Context ● 139

terms of expense, returns, timeframe, and consuming and wasteful. SPS would require a amount of people and materials placed in or- much clearer and stronger coordinating mech- bit; if developed it would be a spur to all forms anism than currently exists for national space of cheaper space transportation. programs, since not only NASA and DOE but a number of other departments and agencies SPS’s effect on space projects would depend would be involved. 34 to some extent on the type of SPS that would be developed, the size of each unit, and the Extensive NASA involvement in SPS would size of the entire system (as well as the scope require clarification of NASA’s appropriate and type of space program in place at the role in commercial applications ventures, and time). A geosynchronous microwave SPS simi- perhaps modification of NASA’s charter. Both lar to the reference design would require ex- underlying policy— i.e., to what extent NASA tensive transfer vehicle capacity and hence shouId operate applications systems, such as lead to accelerated development of EOTVs, Landsat and communication satellites—and chemical-powered personnel vehicles, and specific procedures for turning over patents, manned GEO construction stations. A laser- technology, and hardware to private industry SPS in LEO, on the other hand, would require or other Government agencies, have been sub- relatively little LEO to GEO transfer capacity. ject to continuing controversy. * A mirror-system might need even less up- It is probable that a separate public or graded Iift or construction capacity in order to quasi-governmental body would eventually be be fully deployed (see ch. 5). set up, outside of NASA and DOE, to manage A large SPS system consisting of many satel- an SPS program. Such a decision would be in- lites would tend to have greater economies of fluenced by, among other things, the desired scale, leading to the development of more and mix of public and private funding, and the different sorts of vehicles, and greater mass- degree of international involvement. Possible production and automation. In-orbit process- forms such a body might take are discussed in ing of lunar or asteroidal raw materials would chapter 9, Financing Ownership and Control, also be feasible only if a very large system and in chapter 7. were built, to justify the front-end costs of lunar mining and orbital processors. Indirect Effects and “Spinoffs”

Institutional Structures There would be three kinds of indirect effects of SPS development: Would an SPS program require a change in ● technology and hardware developed for current national institutions? The completed SPS that could have other uses (and that SPS Concept Development and Evaluation otherwise would not be developed or Program33 was a joint DOE/NASA effort, with wouId be developed at a much slower DOE providing most of the management and pace), NASA providing technical support. A decision ● uses of the SPS itself other than providing to have further SPS research, development, terrestrial baseload electric power (and and demonstration efforts managed by DOE that would otherwise not be provided for), would likely prove awkward, since the bulk of and the up-front development costs would be for ● economic/technological changes and ba- space systems; hence DOE would have to pass sic shifts of national attitudes most of its SPS funding to NASA, or attempt to develop its own contractor relations and in- SPS developed technologies and hardware: house space capability, which would be time- Most, though not all, of these spinoffs would relate to space capabilities. We have already

“Satellite Power Systems Concept Development and Evalua- ‘[J( )1 re[)ort on \ PS .1 nd Government dgenc Ief — In press tion Program, “Program Assessment Report Statement of Find- *See OTA assessment, Space Policy and Applications, in ings,” November 1980, DO E/E R-0085 preparation 140 ● Solar Power Satellites

seen that NASA’s transportation plans include some of this technology could also be used for many elements directly useful to SPS, which ground-based solar projects. SPS development would tend to accelerate or Space or ground-based industries using SPS- modify. Although the reference system calls developed technology or hardware could, at for heavy-lift launch vehicles able to carry 400 least temporarily, compete with SPS for scarce tons to LEO, and a 5,000-ton payload EOTV, resources. A mechanism for allocating prior- the exact types of vehicles needed cannot yet ities might have to be established to resolve be specified. The proper mix between size, competing claims. numbers, and types of vehicles depends on many unknown factors, including the type of Alternative SPS uses; Depending on the elec- system, its location, and the number of satel- tromagnetic environment (i.e., on the type of lites to be built. system used and the amount and type of shielding available), the SPS platform, whether The combination of improved and cheaper in (GEO or LEO, could be used as a station for a robotics and teleoperation, transportation, variety of communication and remote-sensing possible new construction materials (such as equipment. A GEO SPS wouId be especially graphite composites), and human expertise, useful, due to the relatively small number of would make possible many commercial space positions available. Remotely operated optical activities. Large communications platforms, astronomy devices could be placed near or on scientific and industrial research facilities, SPS as a way of escaping the interference processing plants for chemical and raw mate- faced by Earth-based telescopes. Given a large rials —these are a few possibilities. Past ex- amount of space traffic associated with in- perience teaches that commercial exploitation creasing industrial and military space flights, follows in the wake of the development of new the SPS station could become a focal point for capabilities, and cannot be accurately fore- local storage, refueling, and rest and relaxation seen. 35 for crews – a kind of spaceport. Living quarters Space industrialization could be greatly for maintenance crews and construction enhanced by the use of extraterrestrial raw workers could be expanded and upgraded into materials. SPS could lead to lunar or asteroidal occasional (and, initially, very high-cost) mining by fostering the development of trans- tourist accommodations. port and robotics capacity, as well as by pro- SPS electricity could be used in orbit, either viding a major market for processed products at the satellite itself or at remote sites such as aluminum, steel, silicon, and oxygen. equipped with receiving antennas, to provide The most detailed studies have examined min- power for industrial activities. Processing, ing the lunar surface, and launching raw especially of extraterrestrial raw materials, materials to orbiting processors via an elec- could require large amounts of electrical trically powered mass driver. Others have sug- power that might be more efficiently supplied gested mining or capturing a small asteroid, by a central SPS than by building specific elec- preferably a carbonaceous-chondrite asteroid trical capacity. rich in carbon and high-grade iron/nickel ore.36 Establishing such facilities, which might be Some SPS designs, especially the mirror- done in the later stages of SPS development, systems, might produce enough power to be could considerably reduce the costs of used for local climactic modification. This transporting material to high orbits. would require more precise understanding of weather systems than is now available. Orbital On the ground, SPS would require large- mirrors have also been suggested as a way of scale automated production of solar cells; providing nighttime illumination of cities and/or of cropland to enhance growth. 37

‘5 Woodcock, op cit , p 12 3’Drexler, op. cit , pp 10-11 ‘“Woodcock, op cit Ch. 6—SPS in Context . 141

Special mirror surfaces that reflect only SPS might prove equally stimulating. Others specific wavelengths would need to be de- argue that these resources would have been veloped for such purposes. available anyway, and could have been used in more efficient ways. Generic economic and social effects: A successful SPS could be instrumental in provoking Arguments about long-term social vitality an economic upsurge by stimulating new pro- aIso often revolve around the Apollo ex- duction in the aerospace and energy indus- perience. The optimism and vision that tries, and new industries altogether in space characterized the “Apollo decade” are con- fabrication, solar cells, antenna construction, trasted with the pessimism, uncertainty, and and so on. Specific technical advances neces- sense of limits of the post-Apollo 1970’s. Skep- sary for SPS and Iikely to provide economic tics, however, argue that Apollo represented a spinoffs have been mentioned. The likelihood misguided effort to escape from more pressing of a revolutionary new product, comparable in social and political problems, and that the effect to the transistor or microchip, resulting space program lost public support when this from SPS is unpredictable. Estimates of the ag- became apparent39 (see ch. 9). Whether the gregate economic and technical effects of United States will regain some of its former en- large research and engineering projects, such thusiasm for large high-technology projects as Apollo or nuclear reactors, vary enormous- wiII depend partly on the success of current ef- ly. Some credit a large portion of the U.S. forts, such as the Space Shuttle, and on the economic vitality and technical leadership in magnitude and type of benefits that such proj- the 1960’s, especially increases in research, ects offer. engineering, and project management skilIs, to Federal investments in the Space program .38 “Klaus Helss, “New Economic Structures for Space In the ‘8 Drexler, op clt , pp 8-9 I Ightlei, Astronautics ancf Aeronautics, January 1981, p 17 CHAPTER 7 THE INTERNATIONAL IMPLICATIONS OF SOLAR POWER SATELLITES Contents

Page Page

Introduction ...... 145 Use of SPS Launchers and Construction Facilities ...... 171 Degree and Kind of Global Interest in SPS .146 Military Uses of SPS ...... 172 Economic Interest...... 146 ownership and Control...... 173 Noneconomic Interest ...... 153 Foreign Interest...... 174 Legal Issues...... 154 Europe ...... 174 Status of the Geosynchronous Orbit. . . .155 Soviet Union ...... 174 Environmental Considerations ...... 156 Japan ...... 175 Military and Arms Control Issues ...... 156 Third World ...... 175 Common Heritage and the Moon Treaty. 158 Study Recommendations ...... 175 Advantages and Disadvantages of Multinational SPS...... 159 Unilateral Interests...... 160 Multilateral Interests ...... 162 LIST OF TABLES Possible Models ...... 163 Table No. Page National Security implications of Solar 24. Primary Energy Demand...... 146 Power Satellites...... 167 25. End-Use Electricity Demand ...... 147 Vulnerability and Defensibility...... 168 26. Amount of Global Installed Capacity ., .. ..147 Current Military Programs in Space .. ..170 27. SPS Market in 2020/2025...... 151 Chapter 7 THE INTERNATIONAL IMPLICATIONS OF SOLAR POWER SATELLITES

INTRODUCTION

The development of solar power satellites organizations such as the United Nations and (SPS) requires consideration from the perspec- its specialized agencies; multilateral groups tive of its international implications. First, as a such as the Organization for Economic Coop- space technology SPS would operate in a eration and Development (OECD) and OPEC; global medium, outside of any national terri- and regional groupings such as the Common tory, which is subject to international law em- Market and the European Space Agency (ESA). bodied in existing treaties and agreements. On the substate level there are numerous in- Secondly, as a major energy project the SPS terests, including those of private companies, would affect supply and demand for what is by public utilities, and governmental agencies, far the largest commodity traded on interna- that often conflict and that seek to influence tional markets, one that is of vital interest to national decisions. Furthermore, the role of the all countries. Thirdly, because of its tremen- large multinational corporations in interna- dous cost and technical sophistication an SPS tional relations is in some areas very great and system could have a strong effect on the econ- often independent of direct government con- omies of states involved in its construction. trol And finally, development of an SPS and of the launchers needed to build and maintain it may However, for the SPS, national decisions and give its builders significant military and/or interests are likely to predominate. Although economic leverage over other states. the rise of energy as a major global concern has led to the formation of numerous interna- This chapter will look at the SPS primarily tional organizations (such as the International from a political perspective, because in the Energy Agency) and to intense discussion of final analysis SPS development will depend on the global dimensions of energy prices and national efforts, instigated by national leaders, shortages, the overall impact has been to place paid for– in large part– by public funds. The decisions about energy consumption and pro- United States is the only country in which duction more and more firmly in the hands of there is any likelihood that there would be national governments. In general, it seems that significant private-sector responsibility for SPS the role of the state in furthering peace and decisions. The importance of national efforts security, stability, prestige, and economic well- would be especially crucial in the near future being has not been supplanted by other enti- when SPS projects are in the R&D and proto- ties. type construction phases. Forecasting. – Because SPS is a project Actors. – If SPS is developed, Government which, if pursued, will not reach fruition for at involvement would be guaranteed because least 20 years, assumptions must be made SPS would affect vital national interests in a about future political and economic develop- number of areas, e.g., external security, pres- ments. Since radical changes are by definition tige and influence, and economic growth. unpredictable, these will be unavoidably con- Energy policy in itself has become a central servative. In general, it is assumed that the component of national planning in most coun- basic political and socioeconomic alinements tries. of today’s world are likely to continue. In the Nonstate actors would be involved as well. past, fundamental realinements of the interna- On the international level these include global tional political structure have often been the

145 146 ● Solar Power Satellites

result of major wars or of deep-seated altera- creasing skepticism in American and European tions in political and social expectations, attitudes towards the space program and neither of which can be confidently predicted. nuclear energy in the Iate 1960’s and early Even relatively small shifts in public support 1970’s, for instance, has decisively affected for various programs can have large effects; in- our current space and energy capabilities.

DEGREE AND KIND OF GLOBAL INTEREST IN SPS

National and regional interest in the SPS will recent energy forecasts to be much lower than stem from an evaluation of the ways an SPS those of only a few years ago. Since OTA system would affect all the components of na- believes that IIASA’s analysis may tend to tional interest outlined above. The degree and overestimate future energy demands (see app. kind of interest shown will vary from nation to C), especially in the advanced industrialized nation. In deciding what institutional structure countries, the following figures should be used to use for SPS development, it is crucial to with some caution. take these various foreign interests into ac- The IIASA projections for primary energy count. In this case, interest can be divided — demand are based on an integrated model in somewhat arbitrarily— into economic and non- which supply and demand are matched on a economic components. The economic interest global basis (see table 24). (See app. C.) in SPS would be focused on SPS’s ability to provide electricity, and hence on the local de- Historically, the rate of growth in electrical mand for electricity over the time SPS be- demand has been approximately twice as high comes available. Noneconomic concerns as that of total energy demand. IIASA predicts would include prestige and national security that it will remain higher, but by a factor of 1.4 interests. instead of 2.0.3 Currently, electricity accounts for an Economic Interest average of 11 percent of global end-use A recently completed study by the interna- energy, ranging from 6.5 percent in developing tional Institute for Applied Systems Analysis countries to 12 percent in the OECD. By 2030, (IIASA), Energy in a Finite World,1 provides the IIASA expects this figure to rise to 17 percent (in both high and low scenarios), with develop- most up-to-date projections of long-range future global energy demand. The IIASA study ing countries using 13 percent and OECD 21 uses a global model with several different percent, reflecting an annual increase in usage 4 scenarios, broken down on a regional basis. of 2.6 percent (low) to 3.4 percent (high). We will present the high and low estimates to give the entire range of predictions; it should ‘Finite World, op. c it , p. 482. be noted that the lower estimates are closer to ‘Ibid those of some recent U.S. studies, such as Energy in Transition 1985-2010, by the National Table 24.—Primary Energy Demand (Quads) Academy of Sciences.2 (See app. C.) In general — 1975 2000 2030 the slowdown in gross national product (GNP) — Low High Low High growth over the past several years, and the OECD...... 146.8 200.3 224.5 266.3 393.4 sharp rises in oil prices in 1979, have caused SU/EE (Soviet Union, E. Europe) ...... 55.0 98.9 110.3 149.4 219.1 ‘Energy in a Finite Worid, A Global Systems Analysis, Energy Developing ...... 37.7 107.0 148.9253.8 453.1 Systems Program Group, International Institute for Applied Sys- Global Total...... 239.5406 .2503.7669.5 1,065.6 tems Analysis (Cambridge, Mass.: Ballinger Publishing Co,, 1981). ‘Energy in Transition 1985-2070 (Washington, D. C.: National S6URCE: Energy in a Finite World; conversion to Quads done by the Office of Technology Assessment. Academy of Sciences, 1979). Ch. 7—The International Implications of Solar Power Satellites ● 147

Electricity use is affected by many factors, Soviet Union — up to 55 percent of coal pro- including changes in end-uses, (such as heat duction in North America by 20306 (see app. C). pumps or electric cars), saturation of demand, and the cost and availability of fuel (see ch. 6). Regional Variations Table 25 shows the IIASA figures for end-use In order to understand how different coun- electricity demand. tries might view SPS, it is crucial to highlight Assuming 70-percent load factors and 15- the major regional differences that will affect percent losses in transmission and distribution, demand for electricity. Foremost among them IIASA estimates for installed generating ca- is the question of regional or national self- pacity in 2030 are shown in table 26. sufficiency.

Although the IIASA report is pessimistic SELF-SUFFICIENT AREAS about the possibility of extensive use of alter- In the 50-year time-frame considered, it ap- native energy sources, such as fusion or pears possible for three major consuming ground-based solar, by 2030, it points out that regions — North America, Soviet Union/Eastern a breakthrough in fusion or solar-cells would Europe, and China –to achieve energy self- change the supply and cost of electricity dras- sufficiency. This would require rapid develop- tically. Cheap photovoltaics might encourage ment of indigenous sources of North American a shift towards a “hydrogen economy, ’’with oil shale, tar sands, and Western coal; for the electricity produced in high-insolation desert Soviet Union, untapped oil, gas and coal re- areas being “stored” and transported as hydro- 5 serves in Central and Eastern Siberia; for gen. China, development of oil and coal deposits Barring such developments, future baseload and expanded exploration in Western China. In electrical demand will be met overwhelmingly all three cases very substantial growth in by coal and nuclear sources (see app. C). IIASA nuclear and/or solar, hydro, and other gen- also predicts that coal will be used extensively erating sources would also be required. With for producing liquid fuels, especially in coal- the possible exception of U.S. and Soviet coal, rich regions such as North America and the none of these regions is likely to export significant energy supplies, since indigenous growth will absorb most new capacity even ‘I bid., p. 163. under optimistic scenarios.

Table 25.–End-Use Electricity Demand (Qe) The costs of achieving regional self-sufficiency would be very high. Development of 1975 2030 North American oil shale and tar sands, for in- — Low High stance, on a scale sufficient to produce oil and OECD ...... 12.5 35.3 50.2 gas in quantities comparable to the large com- SU/EE ...... 3.9 15.5 25.4 mercial oilfields of today, will cost hundreds Developing...... 1.8 23.3 41.3 Global Total ...... 18.2 74.1 116.9 of billions of dollars. Such development will also be “dirty” environmentalIy, involving ex- SOURCE: .Errergy in a Finite Wor/d, p. 659. These numbers should be taken as approximations, since they are based on IIASA estimates of the per. tensive surface-mining, and hence expensive to cent of end-use demand that will be met by electricity. For graphic presentation, see Energy, p. 481. clean up and to regulate. In the Soviet Union, currently the world’s Table 26.—Amount of Global largest oil producer, finding the capital for ma- Installed Capacity (GWe) jor energy investments during the 1980’s will be difficult. Inefficiencies in central planning 1975 2000 2030 practices are likely to be magnified as de- Low High Low High 1,600 3,550 4,390 6,320 9,845

SOURCE: Energy in a Finite World,p. 483. “1 bid , p 669, 148 ● Solar Power Satellites

mands for consumer goods and services in- pean or Japanese shortages. Investment in or crease. legal control of foreign assets provides little insurance against price rises or expropriation, China’s energy production potential is not when the local government is so inclined. well enough known to predict future supplies with any certainty. Oil, coal, and oil shale are The underdeveloped energy-poor regions known to be present in large quantities. Cur- vary greatly in their levels of development and rent modernization plans call for sizable their degree of energy dependence. In virtually energy investments. all cases oil-price rises have seriously hampered economic growth.9 In some instances ENERGY-DEPENDENT AREAS the increases have spurred development of in- Regions without sufficient local resources digenous sources– nuclear plants in Brazil, will include Western Europe, Japan, and large Argentina, and India; biomass in Brazil; portions of the (currently) developing world. numerous small-scale hydro and solar projects Western Europe and Japan can be expected to suited for decentralized generation. It is in the invest heavily in nuclear plants, especially fast less developed countries (LDCs) that the great- breeders. est proportional surge in energy demand and electrical usage will come over the next 50 Unfortunately neither Western Europe nor years, rising from 12 percent’” to 31 to 35 per- Japan is in a good position to exploit alternate cent of global electrical demand (see app. C). nonnuclear technologies to alleviate depend- Decentralized systems can be effective in ence on imported oil. Except for a relatively regions without developed utility grids and small part of Southern Europe, average annual where demand is for small units for domestic, insolation is low—only 1,000 kWh/m2 in Cen- agricultural, and light industrial use. But the tral Europe, compared to 2,500 kWh/m2 in baseload power needed for extensive growth Arizona. ’ Hydroelectric resources are limited and modernization will be expensive and in and already extensively developed. There are short supply. no large wooded areas to provide biomass, and regional cropland in densely populated regions ENERGY-EXPORTING AREAS is scarce. Current energy-exporters include OPEC It is likely that Western Europe and Japan members as well as a few non-OPEC oil pro- will try to develop assured foreign sources for ducers, such as Mexico, Malaysia, and the future needs. This may take the form of joint Soviet Union. Over the next 50 years, many development of capital-intensive North Ameri- current oil-surplus states will cease to export, can energy projects, gaining through partial due to increased domestic consumption and/or ownership an assured source of supplies. decreased output. The time and rate at which Foreign interest in U.S. coal, including invest- current oil production in exporting countries ment in mines and shipping facilities, has ac- will diminish depends on the rate of consump- 8 celerated since the 1979 rise in oil prices. tion as well as future discoveries. IIASA However, it is unlikely that national policy in predicts only small increases in exporting the United States and Canada will permit country production through 2030, with de- extensive ownership of energy resources by mand increases being met primarily by coal foreign countries or enterprises, or significant liquefaction and unconventional oils. The exports of nonrenewable fuels, even to friendly report emphasizes that: “The ‘energy prob- countries. Though the size of the capital re- lem,’ viewed with a sufficiently long-term and quirements may allow for foreign participa- global perspective, is not an energy problem, tion, it will not be enough to alleviate Euro- strictly speaking, it is an oil problem, or, more

‘K. K. Reinhartz, “An Overview of European SPS Activities, ” — Firta/ Proceedings of SPS Program Review, Department of Energy, ‘See Energy in the Developing Countries, World Bank, August’ April 1980, p. 79. 1980, pp 3-6 8See “The Coal Ships,” Washington Post, Oct. 13,1980, p, 1. ‘“I bid , p 44. Ch. 7—The International Implications of Solar Power Satellites ● 149

precisely, a liquid fuels problem.’’11 As de- pared to the cost of mining (because of its mand grows over the next 50 years, the ability bulk), especially overseas and in areas without of countries to import such fuels to make up extensive rail Iinks, While oil and gas are for local shortfalls will dwindle, and prices will suitable for small-scale household use, coal is rise sharply. expensive to store, and prohibitively dirty to use (especially in urban areas). And increased In summary then, the 50-year forecast is for burning of coal could have disastrous environ- an increase in demand for energy of some mental consequences, including acid rain and three to four times, and an increase in demand global temperature increases (see ch. 6). IIASA for electricity of some four to six times with predicts a 10 to 1.50 C average increase, rates being somewhat higher in the currently through 2030, depending on high or low growth developing regions. These forecasts are based rates, on a declining rate of growth in GNP, averag- ing some 2.7 percent (in the low scenario) to 3.7 Nuclear plants are characterized by widely percent (high scenario) per year. (Compared to publicized environmental dangers. Even if a global average of 5 percent from 1960 to these can be resolved, public opposition to 1975.) In general, energy scarcity will cause nuclear power, as well as the rapidly increasing higher prices, reducing demand and increasing costs of building new nuclear capacity, have supply. The question is whether future supplies already delayed the production of nuclear will be so high cost as to force a radical change generators, especially in the United States in Iiving standards and growth rates. Maintain- (where alternative fuels are more readily ing a moderate rate of growth in the developed available than in many other countries). Fur- countries and a somewhat higher growth rate thermore, the spread of nuclear technology, in the developing world —to provide for popu- especially breeders, into more and more parts lation increases as well as the prospect of real of the world will almost inevitably make it increases in living standards —will place de- easier for more states to manufacture nuclear mands on energy resources that guarantee that weapons. Since uranium is concentrated in energy costs will consume a larger proportion scarce deposits, largely in North America, the of national income than in the past. IIASA Soviet Union, and parts of Africa, many areas predicts an increase of 2.4 to 3.0 times in the will be inclined to depend increasingly on proportion of gross domestic product (GDP) breeders. The safeguards and restrictions set spent on energy. Even if IIASA’s projections up by the United States to prevent prolifera- prove to be on the high side, future energy tion have been only partially successful when sources can expect to be competitive within a the main reason for building reactors has been very high-cost ceiIing. prestige-they will be even less effective as energy needs make nuclear plants essential. SPS Contribution For these reasons, SPS may be attractive as SPS could begin to provide electricity by an alternative to other methods of generating 2010-20 and could be a substantial source of electricity. In addition, unpredictable factors new power within the selected 50-year period. such as a major nuclear accident or the failure None of the global projections to date has con- of alternative energy sources could spur inter- sidered the possible impact of an SPS system est in the SPS. SPS would by no means replace on future energy scenarios. The rise in elec- coal or nuclear power within the next 50 years, trical consumption is expected to be met by but could reduce otherwise excessive reliance large increases in coal-fired generators and on these technologies. nuclear plants. However, there are serious problems with both methods. Economic acceptance of an SPS system would depend on several factors. Overall costs Coal, like oil, is abundant only in certain of delivered power will be crucial; these must areas. Unlike oil, it is expensive to ship com- be competitive with other systems. Perhaps I I Fjnjte wor/d, Op. cit., P 653 equally important would be the division of 150 ● Solar Power Satellites

these costs between developers, owners, and building and deploying the satellite portion of users and the way these are shared between the system is probably beyond the reach of participating countries. Development of an most of the present LDCs over the next 50 SPS system would require large amounts of years, so that relying on SPS power might be capital and a high level of technical/engineer- seen as undercutting efforts to develop an in- ing expertise. There are three distinct areas digenous energy infrastructure. Payments to with capital and expertise: 1 ) North America; 2) foreign companies for such power would be a the rest of the OECD countries (i.e., Western drain on scarce foreign exchange reserves com- Europe and Japan); 3) the Soviet Union and pared to development of local resources, Eastern Europe. Assuming that extensive co- which cause ripple effects in the economy. operation between the Soviet Union and other User governments would be sensitive about countries is unlikely (see p. 161), the two possi- depending on a foreign high-technology energy ble collaborators have somewhat different in- source, even if costs and other aspects are terests. North America has the requisite tech- favorable. nical/industrial capacity in space transporta- What is the potential global market for SPS? tion and related areas, but is potentially To date, only the studies by Maurice Claverie energy rich, while Europe and Japan have in- and Alan Dupas have attempted to estimate creasing expertise in aerospace and face con- this in any detail. Their recent papers12 present tinued large energy shortfalls. If the future in- a possible methodology for making SPS projec- terest of these possible participants were es- tions. Unfortunately, their results are based on timated, North American interest would rate as energy demand projections completed in 1976 potentially moderate to high and West Euro- and 1978 that are now considered to have con- pean and Japanese (along with some other in- siderably overestimated future electricity de- dustrialized areas–South Korea, Taiwan, mand’ 13 14 (see app. C). South Africa, Australia) as potentially very high. In North America, capital and interest in From these projections Claverie and Dupas SPS would be competing with coal and synfuel estimate the maximum demand for large elec- development, as well as nuclear energy; in the tric powerplants (LEPP) (see map in app. C), rest of OECD, primarily with nuclear develop- and calculate SPS demand assuming either 10- ment. In general, development of technologies percent or 50-percent market penetration by 5 using renewable or inexhaustible fuel sources, gigawatt (CW) SPSs (see table 27). (such as SPS, but also fusion, ground-based Even allowing for the high estimates of the solar, and biomass) would be preferred to energy projections used, the Claverie-Dupas depletable ones. calculations must be considered very rough upper estimates of future demand; in particu- The possible cooperative mechanisms for lar, cost comparisons with alternative sources SPS development and operation will be dis- were not taken into account. Claverie and cussed later (see Advantages and Disad- Dupas attribute much of SPS’s potential at- vantages of Multinational SPS, pp. 159-163). It is tractiveness to environmental and political important here to see that potential SPS users factors rather than strict cost advantages. 15 with limited initial capital and expertise to — contribute to an SPS system might need spe- ‘*M Claverie and A. Dupas, “Preliminary Evaluation of Ground and Space Solar Electricity Market in 2025,” 29th IAF cial incentives to participate in buying SPS Congress, October 1978; “The Potential Global Market in 2025 power. A major economic consideration for for Satellite Solar Power Stations, ” May 1979; “Possible such SPS users might be the lack of direct and Limitations to SPS Use Due to Distribution of World Population and World Energy Consumption Centers, ” 31st IAF Congress, indirect spinoffs from SPS participation. September 1980 Ground-based antenna construction would re- ‘ ‘Edison Electric Institute, Economic Growth in the Future (New York McCraw-Hill, 1976), pp. 215-234 quire large amounts of unskilled labor, but “World Energy Conference, Wor/cf Energy Demand (New York: would provide few technical or managerial IPC Science and Technology Press, 1978) posts. The capability to participate directly in ‘5Claverle and Dupas, “Potential Market, ” op cit., p. 4. Ch. 7—The International Implications of Solar Power Satellites ● 151

Table 27.–SPS Market in 2020/2025 (G We) range from 5 GW down to 0.5 GW (see ch. 5). Development of smaller sizes would greatly 10% of New LEPP 50% of New LEPP improve the market penetration of SPS by miti- CWEa WECb CWR WEC gating two serious obstacles: the large size of OECD...... 135 75 685 365 and the problems of SU/EE...... 40 260 195 reference rectennas, Developing . . . 50 85 430 435 inserting large blocs of power into utility grids. Global ...... 275 200 1,375 995 Rectenna size in the 5 GW reference design *WR - Case Western Reserve. bWEC. World Energy Conference. is 10 x 13 km at 350 N., including a 2 km buf- SOURCE: Adapted from Claverie and Dupas, Potential G/oba/ Market, p. 4. fer zone. Reducing the size of the design to 1.5 GW would necessitate a receiving antenna only 6.5 X 5.5 km, lowering costs and making Within the limits of this study the Claverie- siting more feasible. In European demand Dupas estimates using the IIASA projections centers, mostly located from 450 to 650 N., cannot be duplicated. However, by using IIASA’S estimates of installed capacity in 2030, rectennas would need to be much larger. high population densities, a rough estimate of global demand can be Given Europe’s made. We can assume that 20 percent of ca- many experts have suggested placing recten- 17 pacity will be reserve, to guard against nas offshore in shallow North Sea waters. Similar problems would be faced in the North- outages, and that of the remaining 80 percent, 65 percent will be baseload. Moreover, if we eastern United States, Japan, Eastern China, accept Claverie and Dupas’ estimate that 10 and India. Though apparently feasible, placing percent of world demand will be met by decen- rectennas offshore would add considerably to tralized sources, then the global estimate of their cost. the maximum possible demand for installed Even more important, a reduction in size baseload capacity in 2030 would be: 80 per- would enable SPSs to be used by smaller utility cent (peakload) x 65 percent (baseload) X 90 grids, since utilities in developed countries do percent = (approximately) 47 percent of total not generally make use of single generating 16 installed capacity. Using the IIASA estimates units supplying more than 15 percent of the (tabIe 26) of 6,320 (low scenario) to 9,845 (high) utility’s total capacity, because of the need to GWe, then we get 2,970 to 4,627 GWe as the ensure against generator failure (see ch. 8). potential demand for baseload capacity. Conversely SPSs, even in less than 5 GW units, The amount of new capacity supplied by may be a spur to integration of utility grids in SPS would depend on the percent met by SPS order to make use of the SPS’s large power in- as opposed to alternate generating sources. If crements. Currently, there is widespread in- we assume 10-percent market penetration tegration of national grids in both Eastern and there would be demand for 295 GWe (low) to Western Europe. Western Europe has an inter- 465 GWe (high); if market penetration were as connected high-voltage network, with routine high as 50 percent (which is not probable, at commercial exchanges of power, which is co- least by 2030) there would be demand for 1485 ordinated by organizations such as the “Union to 2315 GWe. However, it should be noted that pour la Coordination de la Production et du 18 conventional generators built from 1990-95 on Transport de l’Electricity.” In Eastern Eu- will still be in operation by 2030; since SPS rope, Comecon has established an integrated would not be available until 2010-15, the new 150-GW grid including all of Eastern Europe capacity market will be considerably smaller and the Ukraine. than the total demand.

The number of satellites this demand repre- ‘7P Q Collins, “Potential for Reception of SPS Microwave sents would depend on their size; estimates Energy at Off-Shore Rectennas in Western Europe,” Fina/ Proceedings, p. 529. “See: “SPS-The Implications for the Utility Industry,” “Arnaldo M, Angelini, “Power for the 80’s: A Challenge for working paper for OTA workshop, July 1980, p, 12, Western Europe,” Spectrum, September 1980, p. 44. 152 ● Solar Power Satellites

Successful integration of national grids is Geographical location may also be an impossible only where there is an expectation of portant factor to developing countries. If the long-term stable relations with neighboring SPS were located in geostationary orbit, it countries. Unfortunately, though LDCs could would cost more to beam power to areas benefit greatly from regional interconnections, located far north or south of the equator. such expectations are rare in developing Europe, as we have seen, is at a disadvantage; regions where integration may be necessary to the Soviet Union is in a similar position. accommodate large blocs of power, and to Equatorial and tropical states, on the other share the costs of building expensive recten- hand–most of them LDCs–would be in bet- nas. Countries and regions with a successful ter positions to build small-size rectennas. history of cooperation in other areas would be Cheaper power could be an incentive to indus- most likely to join together for SPS integration trial development and foreign investments. as well. In addition, an equatorial position is optimal In many developing regions, where the bulk for launching payloads into orbit, since the of the population lives in rural areas, the Earth’s rotational speed at the equator (ap- feasibility of large centralized power plants is proximately 1,000 mph) is higher than at other reduced by a lack of costly infrastructure, places on the Earth’s surface. Spaceports for especially transmission lines and end-use sending up SPS construction material might capabilities. In such an environment decen- profitably be located near the equator, pro- tralized generating capacity is preferable to viding benefits for the countries in which they SPSs or other large plants. It has been sug- are placed in the form of rents, infrastructure gested19 that such countries may be able to investments, and training of local administra- make use of large amounts of electricity for tors and technicians. producing liquid fuels, such as methanol, di- Earlier it was assumed that the Soviet Union, rectly from the basic elements; such fuels can barring some radical change in its political and be easily integrated into economies that cur- social institutions, would not participate in a rently depend on kerosene or wood for cook- cooperative SPS venture, except with its East ing and heating. However, using electricity in European allies. As a major space power, the this fashion would not be economically feasi- Soviet Union has the ability to go it alone, ble. Methanol can be produced from coal at a though without a global market for its product projected cost of $0.50 to $1 .00/gal. But at the costs would be considerable. The Soviet 5q/kWhr, the cost just to separate from water Union has a number of economic reasons to the amount of hydrogen necessary to make a consider an SPS system, including its increas- gallon of methanol also lies between $0.50 and ingly remote and expensive conventional $1.00. There would be the further expense of energy resources, and the large investment it providing the necessary carbon (which could has put into its space program (currently esti- be provided from carbon dioxide taken from mated at some 1.5 to 2 percent of GNP, com- the atmosphere). However, producing meth- pared to 0.3 percent in the United States21). anol from biomass or from coal (in which the The large distances involved in providing elec- hydrogen, carbon, and oxygen necessary to tricity to many areas within the Soviet Union manufacture methanol are already present) are an incentive to develop a system in which would be far more cost effective. A more power can be sent directly to the area being reasonable need for SPSs might be for energy- served, without transmission lines and without intensive uses such as desalination of sea- transporting fuel long distances, The Soviet water or fertiIizer production. 20 These projects Union has a penchant for big projects, espe- might be coordinated on a regional basis. cially when competing with the West. How- “J. Peter Vajk, Doomsday Has Been Cancelled, Peace Press, ever, currently there is no firm indication that 1978, Z“”D. Criswell, P. Glaser, R. Mayor, et al., The Role of Space Technology in the Developing Countries,” Space So/ar Power “Walter A McDougall, “The Scramble for Space,” Wi/son Review, vol. 1,1980, p. 99. Quarter/y, fall 1980, p. 81. Ch. 7—The lnternational Implications of Solar Power Satellites ● 153

the Soviet Union intends to proceed with an another, as Khrushchev used to claim, they are SPS. still a vehicle for peaceful competition, and a way of impressing allies and potential allies Noneconomic Interest with individual achievements. Because of its scope and visibility, the SPS would be a major Any SPS system would have numerous non- symbol of successful efforts in advanced tech- economic aspects relating to national prestige nology. “Visibility” here is meant literally:23 a and security, and different national and re- completed SPS, even in geosynchronous orbit, gional interests can be expected to conflict. would be easily visible to the naked eye. The There are three separate “arenas” in which impact of such an effort would be direct and such confIicts might arise. great. It is unlikely that the Soviets could allow a U.S. or Western SPS to go unchallenged. If Within OECD they felt they could not compete successfully, Although cooperation between the United they would be likely to try to block construc- States and other OECD allies is probable, there tion by emphasizing environmental dangers or would likely be a high degree of competition supporting Third World demands for shared centered around economic interests. Control control over orbital positions. On the other of any joint program, the division of respon- hand, a Soviet SPS effort would encourage sibilities between countries, and the apportion- U.S. projects by acting as a spur to public ment of economic benefits to be gained from opinion and raising fears of Soviet ascendancy. contracts let during R&D and construction, are all potential problem areas. In the case of SPS, North-South the industries involved —aerospace and ener- Many Third World states would be antago- gy—are high-prestige ones in which many nistic to SPS development, insofar as control countries wish to develop independent capa- of the system rests with industrialized coun- bilities. Fear of economic and technological tries, West or East. These states would be con- dominance by the United States, or of U.S. cerned about increased economic and techni- failure to follow through on program commit- cal dependence on the “North,” and the ments, may be a spur to accelerated develop- limited opportunities for meaningful participa- ment of European or Japanese launch vehicles tion in an SPS system. The SPS could be and construction facilities. The ESA’s Ariane charged with diverting funds from develop- expendable launcher program has been largely ment projects and with increasing the gap be- motivated by worries about such dependence, tween the developed and underdeveloped especially by France, Ariane’s prime mover. worlds. International forums such as the Japan has announced plans for a new genera- United Nations and its specialized agencies tion of launchers, and non-OECD countries could be used as foci for investigations of any such as Brazil and India have built sounding proposed SPS systems and for discussion of rockets and satellites. Increased competition legal measures to bloc them or to give the with the United States can be expected over LDCs various sorts of leverage. the period of SPS development.22 Many developing countries have invested East-West heavily in industries such as steel and oil re- fining in part because of the prestige value of Development of an SPS by the Soviet Union such large and advanced sectors. Energy pro- would have major international consequences. duction is a prominent example–witness Since Sputnik, each side has reacted to the ac- atomic reactors and hydroelectric projects tions and statements of the other. Although such as Egypt’s Aswan Dam. The SPS could be space successes may no longer be seen as resented because it is unavailable to LDCs; proof of the superiority of one social system to *’See” Jerry Grey, Enterprise (New York: William Morrow & Co., 221 bid., pp. 71-82. 1979), p 225

83-316 0 - 81 - 11 154 ● Solar Power Satellites

only the receiving antennas could be built on The oil-exporting states are in a special posi- home territory with local resources. Converse- tion. An SPS would by no means eliminate oil ly, large amounts of scarce capital might be demand and may prove beneficial by helping spent trying to buy an SPS (if they are for sale) to reduce pressure on exporters to increase and the lift capacity to service it in an attempt production to satisfy rising export needs. to “keep up” with the advanced countries. Countries with large populations and relatively small reserves, such as Nigeria, Indonesia, The “South” is by no means monolithic, and, China and Malaysia, may view SPS as insur- if SPS were built, many states would be poten- ance against the upcoming depletion of their tial supporters, some because of the benefits oil supplies and may choose to invest some of of less expensive electricity and others their current earnings in the hope of long-term because of the prospects for future participa- gains. On the other hand, exporting countries, tion. The most likely supporters of an SPS especially those with long-term reserve poten- would be energy-poor countries with a rapidly tial such as Saudi Arabia, have no immediate developing urban-industrial base, such as use for an SPS and may be tempted to side Brazil, Argentina, Kenya, Turkey, India, and with other LDCs —for political and cultural South Korea. Any system that reduces Western reasons — in attempts to put pressure on the imports of OPEC oil reduces pressure on prices West for greater LDC control. Soviet support and means less expensive supplies for for such measures could cause the SPS to vulnerable LDC importers. It has been argued become a highly polarized issue in which the that firm plans for building an SPS would of Soviet bloc and the nonalined states seek con- themselves put a “cap” on oil price rises by cessions from the West— a not uncommon sending a signal to exporters that Western im- phenomenon in recent international affairs. ports will drop in the future. z’

Z4HOuSe committee on science and Technology, SpS Hearings on Ff. f?. 2335, 96th Cong., March 1979, pp 132-180,

LEGAL ISSUES

The United States and other space-capable The most important and comprehensive of states are currently bound by a number of the currently applicable agreements, all of agreements that would affect SPS develop- which have been ratified by the major space ment.25 Much of existing international law has powers, is the 1967 Treaty on Principles Gov- been formulated at the United Nations (U. N.) erning the Activities of States in the Exploration by the Legal Subcommittee of the Commit- and Use of Outer Space, Including the Moon tee on the Peaceful Uses of Outer Space and other Celestial Bodies . In 1979, COPOUS (COPUOS). COPUOS has been in existence agreed on a final version of a new treaty, the since 1959, when it began with 24 members. It so-called “Moon Treaty, ” which has so far not now has 47, with membership expanding as been signed by the United States or other ma- international interest in space matters has in- jor powers. The Moon Treaty applies to the creased. COPUOS decisions have been made Moon and other celestial bodies, but not to by consensus rather than by outright voting.26 Earth orbit. In addition to COPUOS, important decisions on frequency allocations and orbital 25 See Stephen Gorove, SPS lrrternatjona/ Agreements, DOE/NASA contract No, EG-77-C-01-4024, October 1978; Carl Q. positioning are made by the International Christol, SPS International Agreements, DOE/NASA contract No Telecommunications Union (ITU), a special- EG-77-C-01-4024, October 1978. ized U. N. agency. 2’Eilene Galloway, “Consensus DeCISiOrlrnaklrlg of UNCOPUOS,” )ourna/ of Space Law, vol. 7, No. 1 Ch. 7—The International Implications of Solar Power Satellites . 155

As a new arena of human exploration, legal and Western Europe —as legally and scientif- norms with respect to outer space have had to ically untenable. Control over the orbit by a be defined. This has been done through a grad- few states would prevent free and equitable ual process shaped by actual usage, the exten- access to a crucial position by space-capable sion of existing law, and the explicit adoption countries. of common principles and regulations. The equatorial claim must be SPP - ‘ -- ‘ - The outstanding international legal issues context of various attempts by tr that might affect SPS development are: to gain leverage over ec~ - activities otherwise o - 1. the status of the geosynchronous orbit, seven Bogota sig~- and the source of jurisdiction over the Ecuador, lnd~~ placement of satellites; (Brazil 2. provisions against environmental disturbances; 3. the military uses of space and arr- trol implications; and 4. issues relating to the -“ facilities and ber ‘“ tion of the kind” p“

‘ is ., torums ..Y of special geosynchronous use ..pport among many coun- likely to be discussed further when ~~ considers the definition of outer Ace next year, 28 and when the ITU convenes a special administrative radio conference on ‘Y u . . .dl ..~ct ~eiimitation be- orbital use in 1984 or 1985. i Ider the jurisdiction of the Even if parts of the orbit cannot be appro- , y ing underneath the area con- priated by sovereign states, there is still the d-and outer space has never been de- problem of allocating positions and of decid- ,led. In recent years a number of states ing competing claims to scarce orbital slots. located on the Equator have claimed jurisdic- The question here is part technical and part tion over the geosynchronous orbit on the legal: How much space is there, and what con- grounds that it is not part of “outer space” but stitutes infringement? This is dependent on the is determined by the Earth’s gravitation, and is state of technology, since “infringement” is a limited natural resource requiring national not so much a problem of two or more objects control. In December 1976 eight equatorial trying to occupy the same place as of electro- countries issued the Bogota Declaration assert- magnetic interference between nearby satel- ing their position and laying claim to the lites (see ch. 8). SPS satellites would not only orbital segments lying over their respective ter- be very large but would, especially if using ritories. microwaves, radiate a great deal of energy at The equatorial states’ claims have been re- radio frequencies. Each SPS would have to be jected by the majority of other nations— allocated a position and frequency to mini- including the Soviet Union, the United States, ‘“See Gorove, SPS Agreements, op. cit., pp. 14-21; and Delbert 27space Law se/ected Basic Documents, 2d cd,, U.S Smith, Space Stations: /nternationa/ Law and Po/icy, Westview Government Printing Office, 1978, p 26 Pre~s, 1979 156 ● Solar Power Satellites

mize interference with a rapidly growing reallocation clearly has considerable support number of satellites (see ch. 8). Many spectrum among have-not states. Established users such users have worried that SPS operation would as the United States remain opposed to a priori disrupt communications and sensing tasks, assignment of slots and frequencies. Again, the others that the initial SPSs would use up the ITU debate is part of LDC attempts to gain available electromagnetic space, preventing leverage. SPS development could be affected exploitation by latecomers. Since the accept- by attempts of disaffected states to block able limits vary with the size and type of SPS development by denying frequency alloca- used, the size and type of future commu- tions, or by making consent contingent on con- nications satellites, and advances in trans- cessions by states with the most interest in mission technology, it is impossible to say at SPS.31 this time how many SPSs could be built without unacceptable interference. Environmental Considerations

Allocation of frequencies and positions has The 1967 treaty states, in article VI 1, that to date been the province of the ITU, whose each state is “internationally liable for dam- 1973 convention states that stations “must be age” to others caused by its activities in established and operated in such manner as space. 32 The 1973 “Convention on Interna- not to cause harmful interference of other tional Liability for Damage Caused by Space members, or of recognized private operating Objects” amplifies on these responsibilities.33 agencies, or other duly authorized operating agencies which carry on radio services, and Hence, SPS developers might face lawsuits which operate in accordance with the provi- or other forms of grievance if the SPS damaged sions of the Radio Regulations.”29 Whether the the global or local environment. The extent of ITU would have jurisdiction over noncommu- various environmental effects is unknown and nications satellites such as SPSs is unclear.30 In in need of further research (see ch. 8). Even if November 1979, at the ITU’s World Adminis- operation of any one SPS had no effect outside trative Radio Conference, the United States of the state making use of it, designing a raised the question of allocating a frequency globally marketable system to meet widely position for future SPS testing; the proposal varying national standards could add signifi- was referred to a specialized study group for cantly to costs. The possibility of large Iawsuits evaluation and future decision. could make insurance expensive or impossible to procure; large risks in the nuclear industry Allocation decisions by the ITU have been made it necessary for the Federal Government characterized by debate over the first-come to provide insurance, and similar provisions first-served tradition, whereby first users have might have to be made for SPSs. priority in the use of frequencies and orbital slots. Newly space-capable states as well as Military and Arms Control Issues LDCs and others who intend to develop such capabilities in the future have urged, since The 1967 treaty commits states “not to place 1971, that all states have “equal rights” to fre- in orbit around the Earth any objects carrying quencies and positions, and the ITU has called nuclear weapons or any other kinds of both the radio spectrum and the geostationary weapons of mass destruction” (art. IV) and in orbit “limited natural resources” that “should general to carry on activities “in the interest of be most effectively and economically used.” A maintaining international peace and security number of LDCs have proposed that space be and promoting international cooperation and reserved for their future use. Since there is no understanding” (art. III).34 The 1977 “Conven- legal basis for permanent utilization or ownership of positions, the possibility of future 3’ Ibid , pp. 21-33, 32 Space Law, op. cit., p. 28. zgspace Law, P 87 Op. cit., “Ibid , pp. 49-69. 3oGOrove, op. cit., PP. 27-33. “lbld , p. 26. Ch. 7—The International implications of Solar Power Satellites Ž 157

tion on the Prohibition of Military or Any for shuttle construction. In the absence of Other Hostile Use of EnvironmentaI Modifi- their own SPS program, obstructionist tactics cation Techniques” prohibits the activities im- by the Soviet Union could be expected. plied, with “environmental modification tech- Although unlikely, use of the SPS for niques” defined as “any technique for chang- directed-energy weaponry, either directly, or ing the dynamics, composition or structure of as a source of energy to be transmitted to the Earth, including its biota, lithosphere, remote platforms, or for tracking, would be hydrosphere and atmosphere.” (art. 11).35 These regulated by the 1972 Anti- Ballistic-MissiIe general principles obviously allow for criticism (ABM) Treaty between the United States and of some SPS designs as having weather modifi- the US.S.R. Article V of the treaty states that cation potential, requiring restrictions or “each party undertakes not to develop, test, or redesign to reduce such effects. Whether an deploy ABM systems or components which are SPS’s microwave or laser capabilities would sea-based, air-based, space-based, or mobile class it as a weapon of “mass destruction” and land-based.” hence make it illegal under the 1967 treaty is unclear, but it is very likely that such charges Use of the SPS for ABM purposes would would be made in the event of SPS deploy- hence be banned. Since any laser or micro- ment. Development of an SPS might entail re- wave SPS is potentially capable of being so negotiation of relevant treaties or special sys- used, the Soviet Union (or the United States if tem design to minimize its usefulness as a the tables were turned) would undoubtedly in- weapon. sist on assurances and inspection provisions to prevent such developments. The ABM treaty Military satellites for communications and provides for inspection and verification by remote sensing are currently used by several “national-technical means, ” i.e., by remote countries, and presumably use of the SPS plat- surveillance. Onsite inspection has historically form for such purposes would not constitute a been refused by the Soviet Union, although the change in accepted practice. The Soviet Union 1967 treaty, and the “Moon Treaty,” include has tested antisatellite satellites on several oc- provisions for mutual inspection of lunar and casions, and the United States and Soviet celestial facilities. SPSs would need to be Union have conducted informal talks (cur- monitored by Earth- and space-based recon- rently suspended) on limiting antisatellite naissance means. weapons. The Soviet Union has complicated matters by stating that it considers the Space Although the ABM treaty is of “unlimited Shuttle an antisatellite system, an unaccept- duration” there has been considerable senti- able proposal for the United States.36 U.S. Air ment in the United States for its abrogation or Force involvement in the shuttle program and renegotiation in order to provide a defense for Department of Defense (DOD) plans for mili- America’s increasingly vulnerable land-based 37 tary missions provide Soviet negotiators with ICBMS. Abandonment or substantial change their rationale. Insofar as the Soviet Union is in the treaty might allow for development of making this argument for bargaining purposes directed-energy weapons in conjunction with in the absence of a similar Soviet system an SPS system. Renewed negotiations may (similar to Soviet proposals to ban atomic have to take SPS development into account, weapons in the period when it lacked its own perhaps by specifying SPS designs that make it and to prohibit satellite reconnaissance in the unusable as a weapons system. An SPS that early 1960’s) such a charge could also be made used lasers as its energy-transmission medium against heavy lift launch vehicles (HLLVs) used would be particularly destabilizing and it is possible that arms control considerations jSAgreernent Governing the Activities of States on the Moon would prevent such a system from being built. and Other Ce/estia/ Bodies, pts, 1 and 2, U.S Government Print- ing Off ice, May 1980, p. 256. -—— “’’Soviets See Shuttle as Killer Satellite, ” Aviation kVeek and “See Carries Lord, “The ABM Question, ” Commentary, May Space Teclmo/ogy, Apr. 17,1978, p. 17 1980 758 ● Solar Power Satellites

Common Heritage and the Moon Treaty voted for a “declaration of principles” that prohibited activities “incompatible with the in- The 1967 treaty states, in article 1, that “The ternational regime to be established.”42 Until exploration and use of outer space . . . shall be the regime is more clearly defined, it is im- carried out for the benefit and in the interests possible to tell whether current activities will of all countries, irrespective of their degree of be incompatible or not. The effect of this economic or scientific development, and shall climate of uncertainty and of the possibility 38 be the province of all mankind.” The draft that future regulations may make mining un- version of the Moon Treaty adds (art. IV). “Due profitable has been to keep sea-bed mining regard shall be paid to the interests of present consortia —several of which were formed in and future generations as well as to the need the 1970’s—from proceeding with the large to promote higher standards of living and con- capital investments needed for commercial ex- ditions of economic and social progress and ploitation. development in accordance with the Charter of the United Nations. ”39 The exact meaning of Article Xl of the draft Moon Treaty provides these provisions is unclear, beyond a negative for a regime (to be established sometime in the duty not to interfere with the activities of other future) with the following provisions: states or to harm their interests. A positive in- 1, The Moon and its natural resources are terpretation that “would impose on space the common heritage of mankind . . . powers the obligation either to permit other 5. States parties to this agreement hereby countries to use the former’s space vehicles or undertake to establish an international to share the financial benefits of its space ac- regime, including appropriate procedures, tivities, ”40 has been made by some LDCs but to govern the exploitation of the natural has not received widespread support. Since resources of the Moon as such exploita- 1958, U.S. policy has been to encourage inter- tion is about to become feasible . . . national cooperation. U.S. launch capabilities 7. The main purposes of the international have been available to all countries, on a reim- regime to be established shall include . . . bursable basis, for peaceful and scientific pur- (d) an equitable sharing by all States poses. Parties in the benefits derived from In 1970, A. A. Cocca of Argentina proposed a those resources, whereby the interests draft treaty in UNCOPUOS which provided and needs of the developing countries, that the natural resources of the moon and as well as the efforts of those coun- other celestial bodies be “the common herit- tries which have contributed either age of mankind.” This terminology was bor- directly or indirectly to the exploration rowed from similar language used in the Law of the Moon, shall be given special of the Sea negotiations in 1967 for regulating considerate ion. 43 seabed resources that lie outside of national Moon Treaty opponents have argued that jurisdiction. the treaty, like the proposed Law of the Sea, In the course of the Law of the Sea negotia- would delay or prevent commercial invest- tions (not yet concluded) “common heritage,” ment in space activities, and would in any case has come to mean common ownership, “by substitute a state-run international body for 44 mankind as a whole” (art. CXXXVII), 14 with private enterprises. Because of the already commercial exploitation to be regulated by a developed technology for deep-sea mining yet-to-be-formed “international regime” which (most of it U.S.), the Law of the Sea negotia- will distribute part of the returns among par- tions have become absorbed in detailed dis- ticipating countries. In 1970, the United States cussion of the regime to be established, while

3aSpace Law, op. cit., p. 25 — 8 -89 39 Agreement, Op, Cit., pts. 1 and 2, PP 8 “Agreement, op cit , pt. 3, August 1980, pp. 295-307 ‘“Smith, op. cit., p. 92. “Agreement, op cit , pts. 1 and 2, pp 91-92, “Agreement, op. cit., pts. 1 and 2, p 74 “See ‘ 1-5 Memorandum” in Agreement, op cit., pp. 377-378 Ch. 7—The International Implications of Solar Power Satellites ● 159

in the Moon Treaty such details have been left heritage” resource requiring explicit allocation to the time when exploitation of lunar or other by an international body. celestial resources is “about to become feasi- In the course of the Moon Treaty negotia- ble.” The eventual outcome of the Law of the tions the United States was a consistent sup- Sea may have an important bearing on the porter, along with virtually all the Third World shape of a future outer space regime. participants, of the common heritage provi- Since the Moon Treaty would not apply to sions, while their most persistent opponent was objects in Earth orbit, SPS would not be direct- the Soviet Union.46 The U.S.S.R. did not accede ly affected. However, the Treaty could have to these provisions until 1979. While the several indirect effects. First of all, in several United States generally interpreted common scenarios large-scale SPS construction beyond heritage in such a way as to allow for some de- an initial demonstration system is economical- gree of private unilateral commercial de- ly feasible only if the satellites are built from velopment, the Soviet Union expressed fears lunar or asteroidal material (see ch. 5). Such that the treaty would lead to an unacceptable prospects would be dependent on a regime suprastate body. The Soviet position was that such as is envisioned in the Moon Treaty, such a body would infringe on the sovereign which would have to grant permission to min- rights of states. The Soviets have also opposed ing companies to extract minerals and build allowing private or nongovernmental bodies to facilities. engage in space activities. Both the 1967 treaty (art. Vl) and the proposed Moon treaty (art. Secondly, it can be argued that solar energy IXV) provide for state supervision of and re- is a celestial resource under the jurisdiction of sponsibility for the activities of nongovern- the proposed regime, and that SPSs (and other mental entities. This “state-centric” approach space-craft) must be granted permission to use 45 is typical of Soviet attitudes in international it. Though such an argument is unlikely to negotiations. find general acceptance, it could be used by interested states to try and gain additional As a result of concerns generated by the Law leverage. of the Sea negotiations, as well as antitreaty lobbying by “pro-space” organizations such as Thirdly, adoption of the Moon Treaty would the L-5 Society, U.S. support for the draft provide a powerful precedent that could af- Moon Treaty has been limited. U.S signature fect the evolution of a future SPS project. It has been discussed in the Senate Subcommit- would legitimize developing countries’ claims tee on Science, Technology, and Space, and by to receive benefits on a par with states that a special interagency committee chaired by have actually invested in launch or construc- the State Department. Prospects for U.S. ap- tion facilities, and give impetus to arguments proval currently appear to be slight. that the geostationary orbit is a “common — “Conversation with Eilene Galloway, September 1980, “Agreement, op. cit., pts 1 and 2, pp 27-38

ADVANTAGES AND DISADVANTAGES OF MULTINATIONAL SPS

No matter what country or organization and regions. However, from the point of -view were to build an SPS, it is clear that construc- of any national government— and to a lesser tion would involve some cooperation with and degree of private corporations as well–it accommodation of the interests of other states would be preferable, other things being equal, 760 ● Solar Power Satellites

to build the SPS as a strictly national venture combination of events, and if cooperation with and to own and operate the system on a uni- foreign governments or corporations is re- lateral basis. jected because of fears that it might slow down the project or otherwise reduce its Unilateral Interests domestic usefulness, it is possible that a unilateral effort would be undertaken. From a corporate viewpoint, it is much There are several other factors that might in- easier to do business within a country than to crease the attractiveness of a unilateral crash do so across national boundaries. Multina- project similar to the Manhattan or Apollo pro- tional ownership or control would complicate grams. Three requirements for such decisions decisionmaking, reduce flexibility, and in- are: 1 ) a crisis, requiring immediate action, troduce a multitude of political strains that which threatens basic national interests; 2) the any company would prefer to avoid. To the extent that foreign markets are attractive, the existence of a workable plan to resolve the company wouId prefer to retain domestic own- crisis; 3) decisive leadership by persons in posi- ership and to sell completed units abroad, tions to implement such plans. ” In the Man- minimizing foreign entanglements. hattan and Apollo cases, the crises involved challenges to national interests that placed a From the point of view of governments that premium, not only on developing the atomic might consider investing in SPS, the desire to bomb or the ability to go to the Moon, but on do so alone would be very strong, for reasons doing so first. of prestige, security, and economics. At present only the United States and the Soviet The SPS would have important economic, Union could even consider such a unilateral ef- prestige, and security implications. Unilateral development by the Soviet Union or the fort. In the longer term, however, it is con- United States would provide a strong impetus ceivable that a European consortium or for the other to do so as well, as long as the perhaps even a single European state—most project could also be justified on other likely France– could also undertake such a project. So could Japan, with possible cooper- grounds. The strength of this impetus would depend on the state of future U.S.-Soviet rela- ation from China, South Korea, and other regional powers with technical expertise and tions. In the 1950’s nuclear weapons and their financial resources. delivery systems were seen as vital to the existence of the state; the space programs of the Is it likely that the United States or the 1960’s as symbolic of each state’s social and Soviet Union would build an SPS in the near economic superiority. It is unlikely that the future? Such a program would be undertaken SPS would be as crucial to East-West competi- only if there were serious doubt that alter- tion as these earlier technologies, unless the native energy sources will be available in the SPS or the launchers needed to build it be- future, or that their costs will be acceptable. come vital elements of military systems. For

This would have to mean that the C02 and en- the reasons given in the next section, Nationa/ vironmental problems of large-scale coal use Security Implications of SPS this is possible were seen to be acute and imminent, or that but unlikely. Hence an equivalent desire to nuclear reactors were deemed unacceptable build the first system–an SPS “race”- is im- due to a major accident and public disap- probable. proval. In addition, alternatives to the SPS such as fusion, ground-based solar cells, and Within the United States certain interests would favor unilateral as opposed to multilat- possible other future technologies, would have to fail to fill the gap (see ch. 6). In the event of eral development. Businesses likely to benefit some such crisis SPS studies must be sufficient- from development, such as aerospace indus- ——. Iy advanced to provide very high assurance “]ohn 1 ogsdon, The Decision To Go To rhe Moon (Cambridge, that such a system would work. Given this M,tss Ml T Press, 1970), p 181 Ch. 7—The International Implications of Solar Power Satellites ● 161

tries or large construction firms, might prefer a such arguments are likely to be less telling unilateral effort that would provide them with there than in the United States. Although vari- most or al I of the contracts, as well as the pros- ous Soviet ministries would seek a say in SPS pect of foreign sales. However, others might development, none has the technical or mana- fear that a unilateral development would dis- gerial competence to displace the military in courage foreign buyers. Some utilities and oil such a project.49 companies might oppose an SPS altogether if In the United States, the Government spon- it competes with energy sources in which they sors two largely separate space programs, a have already invested. Since unilateral devel- civilian one run by the National Aeronautics opment would almost undoubtedly mean a and Space Administration (NASA), and a mili- government-dominated and financed project, tary one run by the Department of Defense. such businesses would be likely to argue that Both draw extensively on expertise and ex- the SPS is unfairly competitive and to demand perience from a large number of private firms. compensation. While an SPS project in the Soviet Union could In the Soviet Union there is no private sector not help but be dominated by the military, a and hence no question of public v. private U.S. project, even one run by the Government, development. Though it is possible that non- could be shared between the military, Gov- Communist states such as India and France, ernment-civilian, and private sectors. Various both of whom have engaged in cooperative combinations could be developed to provide a space projects with the Soviet Union before, desirable mix between public and private, mili- might participate in small ways, it would be tary and civilian authorities.50 In the past, unprecedented for the Soviet Union to engage Government-sponsored projects that might in extensive joint planning or operations with provide guidance and precedent for an SPS nonallied states. Such cooperation in sensitive, program have included the Panama Canal, the high-technology areas involving space ca- Tennessee Valley Authority, and the Interstate pabilities, which in the Soviet Union are run by Highway System. (See ch. 9, Financing, Owner- the armed forces and considered top-secret ship, and Control. ) What is important is the military programs, is especially unlikely. flexibility available to U.S. planners, a flexibili- Hence an international SPS program is not a ty not found in the Soviet Union, which, if a real option for the Soviet Union, given its pres- multinational effort is preferred, makes it ent political and economic institutions. possible to accommodate international partners on various terms. Within both the United States and Soviet Union, the military may argue for a unilateral Both Western Europe and Japan have more program in order to enhance SPS’s military urgent requirements for reliable energy sup- usefulness, which would be destroyed if sen- plies than the two current space powers. The sitive information had to be shared among impetus for SPS development wouId be similar neutral partners or partners who could not be to that for the United States, but the need is trusted not to reveal technical or other details more imminent, and the costs of alternatives, to unfriendly states. In the United States, in the absence of indigenous fossil fuels, are resistance to military involvement is likely to higher. Could an SPS be built in an acceptable be strong, partly to avoid foreign charges of period without extensive U.S. assistance aggressive intent, and also to prevent possible (assuming Soviet assistance is improbable)? military interference in the project’s efficien- 48 cy, as with the Space Shuttle. However, given “See Soviet Space Programs 1977-7975, vol. 11, ch, 2, “Orga- the military’s role in the Soviet space program, nization and Administration of the Soviet Space Program, ” August 1976, pp. 63-82. ‘°For discussions of these issues, see Peter Vajk, 5PS Finan-

“The price for Air Force support of Shuttle funding in Con- c;al/Management Scenarios, DOE/NASA contract No. EG- gress was substantial redesign of the original Shuttle model, low- 77-C-01 -4024, October 1978, Herbert Kierolff, SPS F;nan- ering performance and increasing costs See Jerry C rey, Enter- c;al/Management Scenarios, DOE/NASA contract No. EG- prise (New York: William Morrow & Co , 1979), pp. 66-68. 77-C-01 4024, October 1978. 162 ● Solar Power Satellites

The requisite technical and financial base is estimates a 22-year, $102 billion program for available; strong aerospace industries exist; na- the reference design.52 (See ch. 5, Costs. ) Al- tional and multilateral space programs, such though the R&D costs would be much lower as the European Space Agency (ESA), are in than construction costs, they would be the place. However, both ESA and Japan lack the hardest to finance, and the ones where interna- depth of U.S. industry’s aerospace expertise, tional cooperation would be most valuable. its worldwide tracking and relay networks, and The number of satellites needed for a global above all experience in and development of system would clearly be much larger than for a manned space-vehicles. The most sophisti- U.S. system alone. However, the R&D/proto- cated non-American launch vehicle is ESA’s type costs are essentially the same whether the Ariane, which is still being test-flown and is system is unilateral or multilateral. Since the scheduled to begin commercial operations in very long 30-year period of investment before 1982.5’ The Ariane is a high-quality three-stage payback is the project’s weakest link, it would expendable booster, but it is far smaller than be desirable to spread these costs between a the large U.S. Saturn rockets used for the large number of possible investors. And by Apollo program. And it is far behind the U.S. widening the available pool of capital and ex- Space Shuttle in capabilities, payloads, and pertise, an international effort would have less cost effectiveness (at least to LEO). Since the of an inflationary impact on resources, thus Shuttle itself is too small and expensive for keeping costs down. full-scale SPS construction, ESA is at least two However, it should be realized that an inter- generations of vehicles away from being able national consortium, whether involving private to develop an SPS unilaterally. Producing the firms or government agencies, will tend gen- requisite lift capabilities in an independent erally to increase the overall costs. Under the program would be extremely costly and time- best of circumstances there are costs associ- consuming. ated with doing extensive business across It is clear that any unilateral SPS program borders, with coordinating efforts in different depends on a dramatic and unpredictable in- languages and geographic areas, and with bal- crease in the sense of urgency about medium ancing the divergent national interests of and long-term energy supplies. Even if such an foreign partners. Without careful management increase were to occur, such efforts would be and a high degree of cooperation from the very expensive for any one country or region to states involved, these extra inefficiencies can undertake, especially since crash programs are eliminate any advantage gained from interna- necessariIy more expensive than ordinary ones; tionalizing the project. The experience of Euro- money is traded for time. pean collaborative efforts has been that costs rise as the large number of participants in- Multilateral Interests creases the managerial superstructure and project complexity .53 There are three reasons why interested parties may wish to abandon their preference for The Global Market autonomy in favor of an international effort. These are: 1) to share the high costs and risks; We have previously discussed the SPS’s po- 2) to expand the global market; 3) to forestall tential global market. An international venture foreign opposition and/or promote interna- may improve the marketing prospects of the tional cooperation. system. First of all, potential users and buyers wouId be less concerned about becoming de- costs pendent on a particular country or corporation, which may infringe on national sov- The exact costs of developing, manufactur- .—— ing, and operating a SPS are unknown; NASA 5*K Ierolff, op. cit., pp. 4-5 5 JTestlmony of Dr. Wolfgang Fink, /nternationa/ Space Ac- “Edward Bassett, “Europe Competes With U.S. Programs, ” tivities, 95th Cong., November 1978, U.S. Government Printing Aviation Week and Space Technology, Mar 3,1980, p, 89. Office, p 12 Ch. 7—The lnternational Implications of Solar Power Satellites ● 163

ereignty. Many states, especially LDCs, are pants would use their leverage for concessions concerned about such a situation, particularly in unrelated political or economic areas. How- with regard to U.S. firms. Over the past 15 to ever, mere participation would not forestall 20 years, LDCs have made great efforts to gain opposition. If member interests are not mutu- indigenous control over local industries and ally compatible, opposition is only moved resources, often resorting to nationalization from without to within. The best check on in- and expropriation. The accumulation of finan- ternal obstructionism would be for the major cial and legal expertise by LDC governments participants to indicate their willingness to go means that future dealings with foreign firms it alone, if necessary, rather than allow internal will be more cautious and equitable than in obstacles to destroy the project. Since orga- the past. Also, it is often politically more feasi- nizations quickly develop their own constit- ble for a neutral or nonalined state to deal with uencies, within and without governments, an internationally controlled consortium than which have an interest in maintaining the orga- with a U.S. or Japanese or West European firm, nization, a credible threat to go it alone must especially when internal opposition to such be backed up by national leaders and by in- relationships is strong. vestment in the requisite systems.

A consortium that offered direct participation and ownership to a large number of Possible Models states would improve its marketing position Intelsat, Inmarsat even more. Such participation/ownership, even if on a small scale, would help to familiarize How might such an organization be con- members with the organization’s operation structed, and what are the types of problems and finances, and assure potential buyers that that might be faced? Here it is helpful to look they were not being deceived. A financial at historical examples of international orga- stake would provide an incentive to see that nizations in the space and energy fields. We the system worked efficiently and was suited will look briefly at Intelsat and Inmarsat; at for the needs of a variety of users. cooperative efforts in nuclear power; and at the European Space Agency (ESA). Widespread participation by many countries with different financial stakes and energy re- Of existing bodies, Intelsat and its near- quirements would also present a host of prob- relative, Inmarsat, have been mentioned most lems. Even small investors could be expected often as possible models for an international to lobby for a proportionate share of the SPS project. Intelsat is attractive because it benefits, including profits and contracts, and has been efficient and profitable, and because for a say in policy and management decisions. it has succeeded in including a large number of Investors with similar interests can be ex- participating states. pected to band together. Often, small-stake Intelsat was founded in 1964, largely at the participants with less to lose are willing to use prompting of the United States, to provide in- any available forum to further ideological or ternational satellite telecommunication serv- economic interests unrelated to the business at ices. The initial agreement provided for joint hand. A balance must be struck between the ownership and investment in proportion to the advantage of open participation and the dan- use of the system by each participating coun- ger that such participation could undermine try, and for renegotiation in 5 years to take ac- the organization’s credibiIity and competence. count of experience and new developments.54 At first, Intelsat was dominated by the United Forestalling Opposition, States through its semipublic participant, Com- Promoting Cooperation sat; LDC participation was minimal, and the Because of the importance of the SPS and “Jonathan Galloway, The Po/;t;cs and Technology of Sate//;te the size of the financial stake involved, major Communications (Lexington, Mass.: Lexington Books, 1972), SPS participants could expect that nonpartici- p 75 764 ● Solar Power Satellites

Soviet Union and East Bloc countries refused, Above all, Intelsat came into being through to join, preferring to establish a separate orga- the. dominant interest and investment of a nization, Intersputnik. The permanent agree- single participant, the United States. U.S. ments reached in 1971 reduced Comsat control determination to institute a global communi- and made it easier for low-use countries to par- cation satellite system was due in large part to ticipate. In 1979, Intelsat had 102 members, the Kennedy administration’s desire, at a time with the U.S. share being 24.8 percent.55 (See when the Soviet Union seemed superior in app. E.) manned and unmanned space capabilities, to achieve a space success before the Soviets that Inmarsat is designed to provide positioning would pay off in terms of global prestige and and maritime services between ships and ship- the furtherance of U.S. national interests. The to-shore. Organized similarly to Intelsat, it is 1958 National Aeronautics and Space Act expected to begin operations in 1981, leasing which established NASA proclaimed that its initial satellite services from lntelsat.56 (See space activities “should be devoted to peace- app. E.) ful purposes for the benefit of all mankind.”59 Though Intelsat has functioned relatively In addition to the scientific and commercial smoothly and has shown a good return on in- benefits, improved international communi- vested capital, serious disagreements between cation was seen as a foreign policy plus for the participants have arisen. Many of these dis- United States, that would involve other states agreements have revolved around the allo- as participants under U.S. leadership. The cation of procurement and R&D contracts, technology for such activities was well ad- with member countries competing for pres- vanced and judged to be superior to that of the tigious and high-value shares. Given the pre- Soviet Union. dominant position of U.S. aerospace firms, The centralized management structure thus much of the pressure has been for equitable created, combined with U.S. technical leader- shares for European and Japanese companies. ship and its status as the largest single user of However, some participants, especially LDCs the system, gave Intelsat initial national sup- and others without indigenous aerospace ca- port that was vital in allowing it to operate ef- pabilities, have objected to distributing con- ficiently and with a minimum of delays. The tracts on a geographical or political basis, promise of future renegotiations placated charging that it drives up costs.57 Non-U. S. con- those, such as France, who objected to the ini- tract shares have risen over time (23 percent of tial phase of U.S. dominance. By contrast, the Intelsat 5, the latest model satellite, is foreign establishment of Inmarsat, despite its close built), 58 and future use of ESA’S Ariane launch- adherence to the Intelsat model, took 4 years er and purchase of European communication of negotiations and some 9 years before the satellites may raise this significantly. (See app. start of actual operations. E.) At the outset of Intelsat negotiations in What do the Intelsat and Inmarsat model 1963, and even at the time of renegotiation in tell us about a possible “lntersunsat?” The 1969-71, the U.S. position vis-a-vis Europe and relatively smooth functioning of Intelsat is the Third World was much stronger than it has largely a result of its initial organization, which been since or is likely to be again, not only in had certain peculiarities not likely to be re- space technology but in general economic per- peated in the future. formance and military strength. This across- 55 Comsat Annual Report 1979, p. 23. the-board preeminence made palatable-a U.S. “’’Operating Agreement on Inmarsat, ” 1976; in Space Law, position that would today probably not be p. 445. Szjoseph N, pelton, G/oba/ communications %’te//jte po/icY: tolerated. Intelsat, Politics, anci Functionalism (Mt Airy, Md.: Lomond Books, 1974), p. 76. ‘a’’lntelsat Being Readied for November Launch,” Aviation 5“’National Aeronautics and Space Act,” 1958; in Space Law, Week and Space Technology, Oct. 27,1980, p 51. p 499 Ch. 7—The International Implications of Solar Power Satellites ● 165

In the foreseeable future, U.S.-European international political debate. ”61 The large size equivalence in technical and economic capa- and importance of SPS contracts would create bilities and the increased self-confidence of strong pressures for geographical allocation; the Third World countries, who were effective- here the experience of the North Atlantic ly excluded from the initial Intelsat arrange- Treaty Organization (NATO) may be more rele- ments, will make a repeat of the U.S. position vant than that of Intelsat. impossible. With regard to an SPS, the United The above is not meant to dismiss Intelsat’s States would not necessarily be the largest experience. Valuable lessons from Intelsat are user, nor would it have a monopoly on engi- the importance of corporate-style independent neering expertise. And the political impetus management; weighted voting by investment provided by Soviet competition, which was share and usage; and interim arrangements vital to the formation of Comsat and Intelsat, that allow a project to begin work and gain ex- is likely to be missing or muted. perience before establishing a permanent The swift and effective establishment of ln- structure. And the positive example of Intel sat telsat depended on several other factors. One and the experience gained in its operation will was the prior existence of international and na- prove helpful in the future. tional entities dealing with global communications. Bodies such as the ITU provided tech- Other Models nical background and legal precedents for Besides Intelsat, with its distinctive com- dealing with communication satellites, and na- bination of state and designated-entity par- tional telecommunications agencies had long ticipation, there are other possible models for experience with short-wave and cable trans- international cooperation, including: 1) joint- missions. No such equivalent exists for the SPS. ventures by privately or Government-owned The initial costs of Intelsat were compara- multinational corporations, on the model of tively low; as of 1980 (through 16 years of Aramco, or the recently formed Satellite operation) a total of somewhat over $1 billion Business Systems, jointly owned by Comsat, had been invested in R&D and procurement. In IBM, and Aetna Insurance, 2) state-to-state addition, the basic research had already been agreements coordinating national space pro- done, and paid for, by the United States; it was grams, such as ESA and its predecessors, ELDO a proven technology with a predictable mar- and ESRO; 3) international agreements on the ket. The SPS would be several orders of magni- development and use of atomic power, such as tude more expensive, would take decades to Euratom; 4) U.S. bilateral arrangements be- produce, and is far riskier. One consequence tween NASA and foreign agencies or com- of communication satellites’ low cost—and panies. the existence of established communication entities—was that the basic decisions, both at PRIVATE CONSORTIUM the beginning and later on, were made by ex- Agreements for joint financing and manage- pert bodies with little public awareness. 6o This ment by nationally based companies can pro- prevented sharp polarization and allowed vide extensive informal coordination across negotiators to give and take without risking boundaries and facilitate the raising of capital outcries at home. SPS negotiations would not on diverse financial markets. (See ch. 9, Financ- take place in this atmosphere. As one observer ing, Ownership, and Control. ) Two major dif- notes, “An SPS is not likely to come into being ficulties would face such an attempt. From the through the nonpolitical activities of technical company’s viewpoint the very high initial in- agencies . . . Decisions about SPS at the inter- vestments and the uncertain legal and regula- national level will be made . . . by the political tory constraints would inhibit commitment leaders of major nation-states in the context of without government guarantees. Many dis-

“john Logsdon, “International Dimensions of Solar Power Sat- ‘OPelton, op. cit., p. 44 ellites Collaboration or Competition?” July 1980, p 3. 166 • Solar Power Satellites

cussants have concluded that public sector fi- The late 1960’s also produced strong pres- nancing would likely be essential for any SPS sures, as in the United States, for projects with project. ’z From the state perspective, especial- economic payoffs, rather than abstract rely outside the United States, there would be research or prestige programs. After Apollo, the luctance to rely on private sector development United States began to look for ways to reduce and control of energy supplies, as well as the costs of its proposed Space Transportation potential antitrust problems (especially in the System. One way was increased cooperation United States) caused by a concentration of with Europe. While France remained suspi- companies. cious that such offers were designed to fore- stal I independent European programs, Ger- ESA many welcomed NASA proposals for joint de- Within Western Europe there have been velopment as a way to gain access to U.S. tech- ongoing efforts to coordinate national space nology and to use of the Space Shuttle. Hence, programs so as to compete with the United whiIe France continued to emphasize launcher States and the Soviet Union. In the early 1960’s development, Germany turned to production two organizations were founded: ELDO (the of Spacelab for NASA. European Space Vehicle Launcher Develop- In 1973, ESRO and ELDO were joined to- ment Organization), aimed at designing and gether as the 9-member European Space Agen- building a European launch vehicle (the cy. Its major projects to date have been: 1) the “Europa” rocket); and ESRO, (European Space Ariane launcher, a $1 billion effort which is 64- Research Organization) to conduct basic re- percent French financed and flown from search. Both groups, and especially ELDO, suf- France’s spaceport in Guiana, South fered from a lack of direction and from America; 65 and 2) Spacelab, an $880 million divergent national interests. ’3 Allocation of project, 55-percent German financed, being contracts was based on the principle of “fair built in West Germany. Other ESA projects return;” contributions to the organization were have included regional remote sensing, mete- in proportion to each state’s GNP, and con- orological, and maritime satellites, and a re- tracts were supposed to be let in similar ratios. gional communications satellite (L-Sat) being This produced intense disagreements and developed under the guidance of Great Bri- delays, exacerbated by cost increases which tain. 66 had to be allocated evenly among the participants. The formation of ESA has not eliminated intra-European difficulties and the problem of In the late 1960’s Europe began to pay in- coordinating national programs. A report in ln- creased attention to the so-called “technology teravia charges that “individual states are tir- gap” between it and the United States. In 1967, ing of the paper-passing and consensus-seeking J. Jacques Servan-Schreiber’s book The Amer- that is involved in getting programs started and icean challenge “polemicized the U.S. eco- keeping them alive within the framework of an nomic invasion of Europe and aroused a pop- international civil-service organization.’’” One ular interest in technology comparable to the resuIt may be a turn towards commercial alter- Sputnik aftermath in the United States.’’64In- natives. With the completion of Ariane a new terest in joint space efforts increased; the firm called Arianespace has been formed, failure of ELDO to produce a reliable Europa made up of European industries, banks, and rocket was heavily criticized, with France and the French National Space Agency, to market Germany claiming their willingness to produce the launcher commercially and in competition it on their own. ‘*See Vajk and Kierolff for further discussion “’’The French Space Effort, ” Interavia, June 1979, p, 508. ‘ 3 See Mihiel Schwarz, “European Policies on Space Science “Edward Bassett, “ESA Planning New Telecommunications and Technology 1960-1978, ” Research Policy, August 1979, pp. Satellite,” A v;ation Week and Space Technology, Dec 31, 1979, 205-242, p 12 “Henry Nau, Nationa/ Po/itics and /nternat;ona/ Technology “’’European Space Programs: An Industrial Plea for Integrated (Baltimore: Johns Hopkins University Press, 1974), p. 55 Effort,ll Interav;a, August 1979, p. 785, Ch. 7—The International Implications of Solar Power Satellites ● 167

with the U.S. Space Shuttle. 68 If successful, been especially motivated by noneconomic Arianespace will provide an example of how considerations. 69 an internationally financed and developed Development of an SPS should not suffer spacecraft can be turned over to a commercial from the extreme obstacles to positive coop- operating group, which could be a model for eration faced in the nuclear field: the military similar development of the SPS. However, all- uses would be less important, the costs much in-all the history of European collaboration higher, and the economic need greater. The in- provides more “dont's” than “do’s” for a tense politicization of nuclear development future SPS effort. shows an extreme case of the forces that can come into play during the development of a NUCLEAR POWER major new technology. International nuclear cooperation is the only model that compares with the SPS in its U.S. BILATERAL ARRANGEMENTS financial and political scope, though the The United States has been very successful security aspects of nuclear power are largely in establishing useful bilateral arrangements unique. Like SPS, nuclear power is a baseload with foreign governmental agencies and orga- electricity source requiring large investments nizations, such as ESA. NASA has been em- and a high degree of technical competence, powered to enter into exchanges of informa- with widely perceived environmental dangers. tion and services, in coordination with other The overall picture of nuclear cooperation parts of Government, such as the State Depart- shows a field where development and opera- ment. NASA has provided launch services, tion, though expensive, is not prohibitively so, technical assistance, and remote sensing and where considerations of national prestige (Landsat) imagery to a large number of foreign and security are extraordinarily high. “Have” customers.’” The network of relationships built countries have had Iittle reason to promote the up over the years could be helpfuI in promot- spread of nuclear technology, except as a prof- ing a multilateral SPS. Direct bilateral co- itable export or a form of foreign aid. The ex- operation with major potential partners in pense of initial development has been justified Europe and Japan might be the best way to ini- as a military necessity (as in the U.S. submarine tiate foreign cooperation and create a climate reactor program). Cooperation is largely moti- conducive to the expansion of the enterprise, vated by the need for agreed-on international especially in the initial less expensive R&D standards and regulations to prevent accidents stages. Such agreements would take substan- and inhibit proliferation. Strictly economic or tially less time to negotiate than regional or energy-supply considerations have played a global ones. ” small role, except as window-dressing, while political and competitive needs have been the “June Sabato and Jairam Ramesh, “Atoms for the Third prime movers. Nuclear development in Third World, ” Bu//et;n of Atomk Scientists, March 1980, p. 39. ‘“Stephen M. Shaffer and Lisa R. Shaffer, “The Politics of in- World countries, such as Brazil and India, has ternational Cooperation: A Comparison of U.S. Experience in Space and Security,” Monograph Series in Wor/d Affairs, vol. 17, “’’New Commercial Organization to Take Ariane Responsibili- book 4, University of Denver, 1980, pp. 15-26. ty,” Aviation Week and Space Technology Apr. 7,1980, p. 45, “Go rove, op. cit., p. 50,

NATIONAL SECURITY IMPLICATIONS OF SOLAR POWER SATELLITES

The potential military aspects of an SPS will fears that the satellite will be vulnerable to be of major concern to the international com- attack, or that it may be used for offensive munity and to the general public. There are weapons (see ch. 9, Public Opinion). Such con- 168 ● Solar Power Satellites

cerns may be decisive in determining the pace ability to transfer power. However, in many and scope of SPS development, and the mode countries, especially LDCs, SPS losses might of financing and ownership that is used. There not be easily replaceable since SPSs, if used, are three basic aspects to consider: 1) SPS would be likely to provide more than 20 per- vulnerability and defensibility; 2) the military cent of total capacity on a national basis. uses of SPS launch vehicles and construction An attack on SPS would also depend on facilities; and 3) direct and indirect use of SPS other factors. If the attacker relies on its own as a weapons system or in support of military operations. Of these it is the second, the exten- SPSs, it may fear a response in kind. If the satellites were owned by a multinational con- sive capability of new launchers and large sortium the attacker might be hesitant to of- space platforms, that will constitute the most fend neutral or friendly states involved. If they likely and immediate impact. were manned— it is unclear whether perma- Vulnerability and Defensibility nent personnel would be required for SPS — the attacker might be reluctant to escalate a con- There are two main segments of any SPS, the fIict by attacking manned bases. ground receiver and the satellite proper. Since The unprecedented position of the SPS, reference-system rectennas or mirror-system located in orbit outside of national territory, energy parks would be very large and com- gives rise to uncertainties as to how an attack posed of numerous identical and redundant would be perceived and responded to. If the components, they would be unattractive SPS is seen as analogous to a merchant ship on targets; the smaller antennas of other designs the high seas, attacks would be proscribed would be slightly more vulnerable. The satel- unless war were declared and outer space were lite segment would be vulnerable in the ways proclaimed a war zone. Otherwise, any attack outlined below, but in general no more so than would be tantamount to a declaration of war. other major installations. Its size and distance In practice, however, experience has shown would be its best defenses. that attacks on merchant vessels have not caused an automatic state-of-war, though they Would SPS Be Attacked? have often played a crucial part in bringing The reasons for attacking a civilian SPS one about. would be that it is expensive and prestigious, not easily replaceable, and that it supplies an It is more likely that the SPS, because of its essential commodity, baseload electricity. In function and/or its stationary position (for cer- determining whether to target an SPS in the tain designs), would be perceived as similar to event of hostilities, the crucial consideration a fixed overseas base or port rather than a ship. would be how much of a nation’s or region’s An attack would then be taken more seriously, electricity is supplied by SPS. In most especially if lives were lost. It will be impor- developed countries, utilities maintain a tant for national leaders to clarify what status reserve of approximately 20 percent of their an SPS would have, particularly in times of total capacity, in order to guard against crisis. A low priority assigned to SPS could en- breakdowns and maintenance outages. If SPS courage enemy states to attack it as a way of supplied no more than the reserve margin, its demonstrating resolve or as part of an escala- loss could be made up; however, given an SPS tor response short of all-out war. system consisting of many satelIites particular regions or industries would be Iikely to receive How Could SPS Be Attacked? more than 20 percent. Making up for losses There are essentially five ways the satellite would require an efficient national grid to portion of an SPS could be destroyed or dam- transfer power to highly affected areas. aged: 1) ground-launched missiles; 2) satellites Increased use of high voltage transmission or space-launched missiIes; 3) ground or space- lines and other measures should increase U.S. based directed-energy weapons; 4) orbital Ch. 7—The International Implications of Solar Power Satellites Ž 169

debris; 5) disruption or diversion of the energy for lasers or microwaves cannot be presently transmission beam. predicted.

A missile attack from the ground on a geo- A missile attack with a conventional war- synchronous SPS would have the disadvantage head might be difficult due to SPS’s very large of lack of surprise, due to the distances in- size and redundancy. The most vulnerable volved and the satellite’s position at the top of spot on the reference and other photovoltaic a 35,000 km gravity well; missiles would take designs would be the rotary joint connecting up to an hour or more to reach, geosynchro- the antenna to the solar cell array. Laser nous orbit. An attack from prepositioned geo- transmitters would be more vulnerable due to synchronous satellites would be faster and less their smaller size, though they would also be detectable. However, a laser or mirror SPS in easier to harden. Attackers would be tempted low orbit could be reached from the ground in to use nuclear weapons, either directly on the a matter of minutes. Lasers or particle beams, satellite, or at a distance. I n space a large (one which might be used to rapidly deface the megaton or more) nuclear blast at up to 1,000 solar celIs or mirrors rather than to cause struc- km-distance could cause an electrical surge in tural demage, would have virtually instanta- SPS circuitry (the electromagnetic pulse (EMP) neous effect. effect) sufficient to damage a photovoltaic SPS72 (though it would have no effect on a Placing debris in SPS’s orbital path, but mov- mirror-system). Such an attack would be par- ing in the opposite direction —such as sand ticularly effective against a large SPS system, designed to degrade PV cells or mirrors– as it could destroy a number of satellites would have the disadvantage of damaging simultaneously. However, like an orbital debris other satellites in similar orbits, and of making attack, it has the problem of damaging all the orbit permanently unusable in the absence unhardened satellites indiscriminately within of methods to ‘sweep’ the contaminated areas the EMP radius. Furthermore, any use of clean. The relative ease and simplicity of this nuclear weapons would constitute a serious method, however, could make it attractive to escalation of a crisis and might not be con- terrorists or other technically unsophisticated sidered except in the context of a full-scale groups. Any explosive attack could have war. similar drawbacks, although since the resultant debris would be traveling in the same Could the SPS Be Defended? direction as most other satellites (which move with the Earth’s rotation) the ensuing damage Defense of orbital platforms can be accom- would be SIight. plished in three ways: 1) evasion; 2) hardening against explosive or electronic attack; 3) anti- If technically feasible, disrupting SPS’s missiIe weaponry. microwave or laser transmission beam, either by interfering directly with the beam or its All of the SPS designs being considered pilot signals, or by changing its position so that would be too large and fragile to evade an it misses its receiving antenna, would be a incoming attack. SPSs may be equipped with highly effective way to attack the SPS. Since small station-keeping propulsion units but not the effects would be temporary and reversible, with large engines for rapid sustained move- such an attack might be favored in crisis situa- ment. tions short of all-out war. Disruption using Hardening against explosive or debris attack metallic chaff would be ineffective against a wouId require rigid and heavy plating. Such ef- microwave beam, due to its very large area. forts would be prohibitively costly, except Laser beams could be temporarily deflected by perhaps for a few highly vulnerable areas. clouds of small particles or by organic com-

pounds that absorb energy at the appropriate ‘*Peter Vajk, “On the Military Implications of Satellite Power frequency. Electronic interference possibilities System s,” Linco/rI Proceedings, April 1980, pp. 506-507

83-316 0 - 81 - 12 170 ● Solar Power Satellites

Hardening against EMP bursts or electronic such capabilities will remain in the hands of warfare would require heavier and redundant the larger developed nations (including a circuitry as well as devices to detect and block number of countries that can be expected to jamming attacks. If incorporated in SPS enter this category in the future). designs from the beginning, these might be The state of technology obviously bears on sufficiently inexpensive to justify inclusion. the question of whether terrorists or criminals Different designs may differ in their vulner- could attack an SPS. Politically motivated ter- ability to such attacks —the photoklystron rorists are generally strong on dedicated man- variation, for instance, would be less suscep- power, not technical expertise. The SPS would tible to EMP than the reference design. be a symbolic high-visibility target, but ter- Antimissile weaponry, whether in the form rorists would be more likely to attack SPS of missiles or directed-energy devices, could launch-vehicles, which would be vulnerable to be placed on the SPS to defend against missile simple heat-seeking missiles, than to threaten and satellite attack. Though potentially highly the SPS directly. effective against incoming missiles, such However, a believable threat of direct at- weapons would be useless against long-dis- tack by terrorists or small powers could be a tance nuclear bursts or remote lasers. Further- spur to defensive measures such as hardening more, they would have unavoidable offensive or antimissiIe devices, which wouId not stop an strategic uses against other satellites and inter- attack by a major power but might be effective continental ballistic missiles (ICBMs), and against lesser threats. would hence invite attack. For these reasons major defensive systems are unlikely to be Sabotage of the SPS through the construc- placed on civilian SPSs. Attacks would be tion force, either for political purposes and/or more effectively deterred by political arrange- for ransom, could not be ruled out. Careful ments and by the use of separate military screening of construction workers — who forces. would be few in number— can be expected, along with supervision while in orbit. The un- Who Would Attack? avoidable conditions of life and construction In most instances an attack could only be in space would make it difficult, especially at carried out by a technically sophisticated na- first, to smuggle explosives or sabotage- tion with its own launchers and tracking sys- devices into orbit. However, a major expansion tems. Threats by such a space-capable power into space involving large numbers of person- against other space-capable powers —say by nel would, in the long run, provide opportuni- the U.S.S.R. against the United States—are ties for sabotage that probably cannot now be possible in the context of a major crisis or ac- foreseen. tual war where the attacker is willing to risk Under current conditions any installation, in the consequences of its actions. Threats space or on the ground, is vulnerable to long- against inferior or nonspace-capable states, range missiles, or to dedicated terrorist groups. such as SPS-using LDCs, might be made at a Reasonable measures to mitigate threats to much lower crisis threshold. SPS should be undertaken, but the dangers It is unclear which states will be capable of themselves cannot be eliminated. projecting military power into space over SPS’S lifetime. It is possible that technical advances Current Military Programs in Space will allow even small countries to purchase off-the-shelf equipment enabling them to at- At present a number of nations use space for tack an SPS, in the way that sophisticated sur- military purposes. The United States and face-to-air missiles (SAMs) are now widely Soviet Union operate the bulk of military satel- available to attack airplanes. However, it is lites, but China, France, and a few other coun- more probable that, over the next 50 years, tries also have military capabilities. The preva- Ch. 7—The International implications of Solar Power Satellites • 171

lent uses involve satellites in low and high or- than particle beams), most experts say that, if bits for communications and data transmis- at all feasible, they will not be available until sion, weather reporting, remote surveillance of the end of the decade. foreign territory and the high seas, and inter- ception of foreign communications. The cru- High-energy lasers and particle beams are cial character of these satellites, especially in desirable because of their speed and accu- providing information on strategic missile racy–light speed for lasers, an appreciable fraction of that for particle beams–making placements and launches, is such that any future war between superpowers will un- them ideal for attacking fast-moving targets such as satellites and incoming missiles. They doubtedly include actions in space to destroy 73 may be deployed on naval vessels, antiaircraft or damage enemy satelIites. positions, and in space. Space-based directed- For these reasons both the United States and energy weapons ‘could theoretically attack the U.S.S.R. are working to develop antisatel- satellites at great distances — up to a thousand lite (A-sat) weapons. The Soviets have in the miles — since their beams would not be at- past tested “killer satellites” capable of tenuated and dispersed by the atmosphere. rendezvousing with objects in orbit and ex- Most importantly, they could also be used to ploding on command. ” 75 The United States engage attacking ICBMs, providing an effec- has not yet tested A-sat weapons in space but tive ABM capability that would radically is developing a sophisticated orbital intercep- change the strategic nuclear balance. Such tor designed to be launched from an F-15 uses depend on attaining very accurate aiming fighter. ” Neither system is capable of reaching and tracking, and extremely high peak-power geosynchronous satelIites without being capabiIities. placed on larger boosters, but such development is probably only a matter of time. Use of SPS Launchers and The United States and U.S.S.R. have held in- Construction Facilities formal talks in the past on limiting or banning A-sat weapons; the most recent such discus- The most important military impact of SPS sion took place in June 1979. These talks have development would likely be military use of been complicated by Soviet claims that the SPS launchers and construction facilities. In Space ShuttIe is an A-sat system. The talks are order to build an SPS it would be necessary to currently “on hold. ” develop a new generation of high-capacity reusable lift vehicles to carry men and An outgrowth of A-sat concern has been the materials from the ground to low orbit. A sec- rapidly increasing interest, on both sides, in ond vehicle, such as an EOTV, would probably laser and particle-beam weapons. ” Although be used for transportation to geosynchronous some have predicted that such weapons couId orbit. be deployed within a few years (especially lasers, whose technology is more advanced In addition, techniques and devices for constructing large platforms and working effectively in space would have to be developed, 73 Clarence Robinson, “Space-Based Systems Stressed,” Avia- along with life support systems and living tion Week and Space Technology, Mar. 3, 1980, p. 25. 74Soviet Space Programs 1977-1975, VOI 1, staff report for Com- quarters for extended stays in orbit. mittee on Aeronautical and Space Sciences, 1976, pp. 424-429. 75Craig Covault, “New Soviet Antisatellite Mission, ” Aviation Improved and cheaper transportation would Week and Space Technology, Apr. 28,1980, p. 20, allow the military to fly many more missions, “Craig Covault, “Antisatellite Weapon Design Advances, ” Aviation Week and Space Technology, June 16, 1980, pp. orbiting more and larger satellites and servic- 243-247 ing these already in place. New construction 77 See articles in Aviation Week and Space Technology of July techniques would enable large platforms for 28, 1980; also Richard Burt, “Experts Believe Laser Weapons Could Transform Warfare in 80’s, ” New York Times, Feb. 10, communications, surveiIlance, and/or di- 1980, p. 1. rected-energy uses to be rapidly deployed. The 172 ● Solar Power Satellites

military would have the further option of fly- broad area (see ch. 5, Electromagnetic Com- ing manned or unmanned missions. patibility).

Without SPS, advanced launch-vehicles and Certain laser designs would be sufficiently construction devices may not be built or, at powerful and focused to cause some immedi- best, be done so much less quickly. The mili- ate damage to people and structures, but tary may hence have a strong interest in par- would not be optimally designed for weapons- ticipating in their development, as they have use. An SPS would use a continuous laser with the Space Shuttle. Whether the military rather than the high peak-power pulsed lasers would actively support the SPS in order to needed for military missions. For such uses, in- benefit from such developments might depend creased focusing of the beam would be re- on whether they think SPS funding would quired, as well as appropriate tracking direct resources away from other military pro- mechanisms. If so equipped, a laser SPS could grams. be used directly against satellites and ICBMs, and also against targets on the ground such as An ongoing SPS construction project with a ships, planes, and oil refineries. Such uses high volume of traffic into space could pro- would be greatly facilitated if a laser SPS were vide opportunities for the military to disguise placed in low orbit, with energy relayed to the operations or incorporate them in normal SPS ground via geosynchronous mirrors. Since a activities. Such a possibility would likely cause sun-synchronous SPS in low-Earth orbit would any unilateral SPS project to be closely moni- of necessity pass directly over many different tored by foreign observers. countries (including the Soviet Union), it could The most significant use of a fleet of be seen as potentially more threatening than a military-capable SPS launchers and crews geosynchronous satellite that remains fixed would be in providing a “break-out” capability above one spot. A geosynchronous laser might whereby, in time of crisis, large numbers of have difficulty tracking low-flying ICBMs and communications and surveillance satellites, satellites, due to its position 35,800 km from antisatellite weapons, or directed-energy plat- the target. forms could be placed in orbit on short notice. This would be similar to the way a national Since the key requirement for directed- merchant shipping or air cargo fleet is viewed energy weapons is a large power supply, any as a military asset, and often supported in SPS that generates electricity directly [i.e., any peacetime because of its strategic signifi- design except the mirror-system) can be used cance. Fear of such uses might be a spur to the to power such weapons. These weapons could development of antilauncher weapons, analo- be built into the SPS platform or placed at a gous to attack submarines or merchant raiders. distance in lower orbits and supplied by lasers from the SPS. The question is whether rela- Military Uses of SPS tively small directed-energy weapons can be designed with autonomous power supplies, Direct Use of SPS perhaps from nuclear reactors. Since weapons used against ICBMs must be capable of firing a The energy transmission beams of the SPS large number of very rapid bursts in order to could have direct military uses. A microwave engage a fleet of 1,000 or more missiles, it may system in geosynchronous orbit would not be that SPS power, if available, would be the generate a beam intense enough to cause most efficient and economical way to supply direct damage to people or installations; it future laser or particle-beam platforms. might be enough to cause minor irritation or panic if used against populated areas. An in- Direct use of the SPS in this way would of tense microwave beam might be used to inter- course make attack in time of war inevitable. fere with short-wave communications over a Extensive defensive armament would have to Ch. 7—The International Implications of Solar Power Satellites • 173

be built in; the offensive weaponry could also energy levels are not high enough, in current be used to defend against missile attacks. designs, to change weather patterns significantly (see ch. 8, Environment). Such use would Any testing, deployment, or use of directed- be prohibited by the 1980 “Convention on the energy weapons in space is presently prohib- Prohibition of Military or any Other Hostile ited by the 1972 ABM Treaty and other space Use of Environmental Techniques.” treaties. A proposed SPS would probably be a topic of future arms control negotiations to Nighttime illumination could be significant, clarify and limit its military implications (see especially in cases of guerrilla warfare or ur- discussion on pp. 156-1 57). ban terrorism where attacking forces rely on Indirect Military Uses darkness and surprise as equalizers. However, fragile Solares mirrors could probably not be In addition to these direct uses, a laser SPS adjusted quickly enough to deal with sudden could be used to supply power to military military developments; rapid deployment of units, providing increased mobility to ground mirrors by the military for specific uses would forces that could dispense with bulky fuel sup- probably be more effective. plies in remote and roadless areas. Given adequate tracking capability it might even be pos- Ownership and Control sible to supply mobile units such as ships, planes, or other satellites equipped with Any of the military uses discussed clearly de- thermoelectric converters, increasing their pend on who owns, operates, and builds the range and allowing them to carry more arma- SPS system. If SPSs are unilaterally owned by ments or cargo. 78 national governments, their military use is far more likely than if run by private enterprise or A geosynchronous SPS is at an advanta- by a multilateral consortium. Fears of military geous position for numerous communications involvement could be an incentive to estab- and positioning uses, military as well as lishing a multinational regime to operate or civilian. Its large size would make it easy to regulate SPSs, and to prohibiting militarily ef- attach equipment to it; the military’s need for fective SPS designs. redundancy makes it convenient to use all available platforms, as does future crowding A key question would be who has effective of geosynchronous positions. Operation of a control over SPSs in a time of crisis. If a private microwave SPS, however, could interfere with SPS consortium, having its own launchers and communications uses unless switched off. crews, has a monopoly on SPS control and expertise, then governments might be hard- SPS’s power and position might make it pressed to take over SPSs on their own. A suitable for electronic warfare uses, such as limited defensive capability would help to jamming enemy command-and-control links. deter any national takeovers. However, This would require the addition of specialized governments might stipulate that in an equipment. emergency they be allowed to commandeer The mirror designs use reflected sunlight SPSs for defense purposes. rather than energy transmission beams. How- A nongovernmental owner can be expected ever, it has been suggested that the reflected to resist any attempts to use SPSs for military light could be used for weather modification functions rather than supplying electricity to or for nighttime battlefield illumination. The commercial users. The threat of Iawsuits or “See Michael Ozeroff, SPS Military Implications, DOE/NASA diplomatic protests at electricity interruptions report, October 1978, pp. 13-1 6; also A Hertz berg, K Sun, and W. Jones, “Laser Aircraft,” Astronautics and Aeronautics, March caused by military preemption might help to 1979, p. 41, deter such actions. 174 ● - Solar Power Satellites

FOREIGN INTEREST

Interest in SPS has been expressed outside of detailed work on the system proper has been the United States, especially in Europe but also done outside of designs to reduce the size of in Japan, the Soviet Union, and some develop- rectennas; European participants have relied ing countries. on U.S. projects for technical information. Suspension of NASA/ DOE research efforts due Europe to lack of fiscal year 1982 funding will have an adverse effect on foreign studies and has led to ● The first significant European study of SPS great disappointment among foreign SPS ex- was done in 1975 by a German firm under perts. 84 A major difference between U.S. and contract from West Germany’s space re- European efforts is that while in the United search organization. States SPS has attracted interest from energy ● In England, the Department of Industry experts and the DOE, European studies have been the exclusive province of organizations funded a study, completed in early 1979, involved in space research .85 that led to a further effort by British Aerospace to investigate the implications of SPS for British industry. ” Soviet Union

● In France, the work of Claverie and Dupas The Soviets have initiated no major known on global demand for SPS has already been studies of SPS, though there have been un- mentioned. verified claims of a Soviet SPS project. It is impossible to tell with certainty what the degree ● The ESA began SPS assessments in 1977, of interest or expertise is; U.S. experts feel the publishing a-number of papers in the ESA Soviets are relying on Western reports and are Journal of 1978. Ruth and Westphal per- far from developing the launchers, microwave formed a study in 1979,80 which examined transmission expertise, and advanced solar offshore sites for rectenna placement, and in cells necessary to consider an SPS.86 Recent 1980 a major report on ground receiving sta- signs of interest include a paper entitled tions was published by Hydronamic B.V. of “Satellite Power Stations” published by scien- the Netherlands.81 In 1978, Roy Gibson, then tists from M.V. Lomonosov State University, director of ESA, said ESA was “intensely in- Moscow in December 1977.8788 At the 30th terested” in SPS,82 and ESA has supported a Congress of the IAF in Munich, September group within the IAF for SPS investigation. 1979, the Solar Power Bulletin reported that: In June 1980, an International Symposium “Although the Soviets were reluctant to dis- on SPS was held at Toulouse, France, with close their level of commitment to a solar representatives from many European coun- power satellite program, Chief Cosmonaut tries and agencies.83 Beregovoy commented ‘that if the United In general, the European studies have fo- States puts up an SPS first, we will con- cused on the European requirements for possi- gratulate you, and if ours goes up first, we will ble contributions to an SPS system. Little expect congratulations from you’. ”89

“K. K, Reinhartz, “An Overview of European SPS Activities,” in Firra/ Proceedings of the SPS Program Review, U.S. Department “Conversation with Jerry Grey, of the Al AA, Oct. 15,1980. of Energy, July 1980, pp. 78-88. “K K Relnhartz, op cit., p 80 80J. Ruth and W. Westphal, “Study on European Aspects of ““Conversations with James Oberg, Johnson Space Center, SPS,” ESA report No CP(P) 1266. and Charle\ Sheldon I I, Congressional Research Service, Septem- “A. R. Bresters, “Study on Infrastructure Considerations for ber 1980 Microwave Energy G round Receiving Station,” Hydronamic Proj- “ 5ovlet fpace Programs 1971-/975, VOI 1, staff report, Library ect, p, 495, November 1980 of ( ongres~, 1976, p 529 ‘*In Jerry Grey, “The Internationalization of Space, ” Astro- ““See statement of Peter Claser In House Hearings on SPS, 96th nautics and Aeronautics, February 1979, p 76 Cong , March 1979, p 218 83 See Peter Glaser, “Highlights of the International Sym- ““5pace \o/ar Power Bu//etin, Sunsat Energy Council, February posium on Solar Power Satellites,” July 1980, 1980, p 1 Ch. 7—The International Implications of Solar Power Satellites ● 175

Japan and by sessions on SPS at international con- ferences such as those of the IAF. Reaction has The Japanese have expressed interest and generally been cautiously optimistic. At the In- funded studies within the National Space ’De- ternational Symposium in Toulouse, Dr. Mayur velopment Agency, though no permanent of- of India’s Futurology Commission claimed: fice for SPS exists. Japanese interest in space “There is no conflict between small scale exploration and industrialization is strong and technologies and the SPS.” Dr. Chatel, former includes plans for several new series of Chief of the UN’s Office of Science & Tech- go Launchers. nology, proposed an international working party to coordinate national programs and per- Third World form assessments. ” The SPS has been placed on the agenda of the upcoming U.N. energy Information about SPS has been spread to conference in Nairobi in the summer of 1981. the Third World by discussions at COPUOS

‘“James Harford, “Japan Showcases Crowing Space Prowess,” Astronautics and Aeronautics, December 1980, pp. 120-125. ‘ l Glaser, op cit

STUDY RECOMMENDATIONS

It is crucial to continue updating long-term development and foreign military space pro- projections as new information becomes avail- grams, and arms-control negotiations. able about developments in the space and U.S. energy and space experts often tend to energy fields. Close attention should be paid pay little attention to the foreign implications to: 1 ) future global electricity demand under of their programs. Since SPS is a system that various scenarios and on a detailed regional may make sense globally but not domesticalIy, basis; 2) evaluation of the impact that possible neglect of the international dimension could external events —wars, oiI embargoes, wide- lead to an unjustified foregoing of SPS devel- spread famine— couId have on U.S. and Euro- opment. In making plans for future R&D pro- pean energy needs; 3) the feasibility of a grams, attention should be paid to involving unilateral SPS System given a global market, and informing potential partners as well as to including estimates of profitabiIity; 4) monitor- considering the ways in which a global system ing of Law of the Sea negotiations and the re- might differ, technologicalIy and institution- sulting international regime with special atten- alIy, from a domestic one. tion to the implications for the Moon Treaty and other space agreements; and 5) weapons Chapter 8 ENVIRONMENT AND HEALTH Contents

Page

Introduction ...... 179 42 Microwave Exposure Limits . .212 43 Research Needs To Help Reduce Environment...... 182 Uncertainties Concerning Public Power Transmission Effects on the Health Effects Associated With Atmosphere and Weather ...182 Exposure to SPS Microwaves Power Atmosphere ...... 183 Densities and Frequency. . .213 Space Vehicle Effects...... 187 44 SPS Development . . . . .217 Electromagnetic Interference ...... 190 45 Estimated Sound Levels of HLLV Terrestrial Activities...... 196 launch Noise . . . .220 Receiver Structure: Weather 46 Representative Noise Levels Due to Modification ...... 205 Various Sources ...... 220 Health and Ecology ...... 207 47 Community Reaction to HLLV Launch Terrestrial Effects ...... 207 Noise~ ...... 221 48 Sonic Boom Summary. . .221 ionizing and Nonionizing Radiation 49 Types of Radiation Found in the Defined...... 209 Different SPS Orbits ...... 223 Space Environment...... 221

LIST OF FIGURES LIST OF TABLES

Table No. Page 30. Regions of the Atmosphere. . . . .183 28. Summary of SPS Environmental 31. Examples of SPS Microwave Impacts ...... 180 Transmission Effects on the 29. Major SPS Environmental Ionosphere and Telecommunication Systems...... 184 Uncertainties ...... ,.182 32. Summary of SPS Atmospheric Effects, .188 30 Power Transmission Impacts...... 184 3 3. Receptor Site Protection Radius as a 31 SPS Space Transportation Vehicles. ...188 Function of the Perimeter laser Power- 32 Exhaust Products of SPS Space Density Level. . , ...... 197 Transportation Vehicles ...... 189 34. Microwave Power Density at Rectenna 33 Space Vehicle Impacts , ...... 189 as a Function of Distance From 34 Summary of Electromagnetic Effects. .192 Boresight...... , . . . , . . .197 35. SPS Systems Land Use...... 198 35. Rettenna/Washington, D.C. Overlay. . .198 36. Summary of Land Requirements...... 199 36. Offshore Summary Map ...... 200 37. Summary of Environmental Impacts of 37. Satellite Power System — Societal Rectenna Construction and Operation Assessment ...... 201 38. Regional Generation and at a Specific Study Site . . . . . 203 Rectenna Allocations ...... 202 38. Summary of Materials Assessment 39. The Electromagnetic-Photon Spectrum, 209 Results ...... 205 40. SPS Microwave Power-Density 39, Annual Environmental Effects of SPS. .206 Characteristics at a Rectenna Site. .. ..211 40. Terrestrial Health and Ecological 41. Comparison of Exposure Standards . .. 216 Impacts...... 208 42. Program Funding...... 216 41. Characteristics of Exposure to 43. Factors Pertinent to Space Worker Reference System Microwaves ...... 211 Health and Safety ...... 222 Chapter 8

ENVIRONMENT AND HEALTH

INTRODUCTION

As a large-scale energy system operating in jeopardizing the economic or technical viabili- both the space and terrestrial environments, ty of the SPS concept. the solar power satellite (SPS) is unique. And The SPS environmental effects and the cost because it is a new concept, our understanding of reducing them must be viewed in the con- and experience of a number of the environ- text of energy technologies, energy needs, mental impacts associated with SPS are lim- other space activities, and the incremental ited. The great uncertainties surrounding these effect on human health and the environment. effects make comparisons between SPS and Preliminary comparative assessments indicate other energy technologies especially difficult. that, in general, those health and environ- While one advantage of SPS is that it would mental impacts of the reference system SPS avoid many of the environmental risks typi- that can presently be quantified would prob- cally associated with conventional energy op- ably be no more severe than for other large- tions such as coal and nuclear, it also would sc aIe electricity generating technologies generate uncommon environmental effects although the uncertainties for SPS are that presently cannot be quantified or com- high). 1 2 3 4 I n fact, when compared to coal, pared to those of other powerplants. The large SPS would be an order of magnitude cleaner uncertainties also tend to provoke public de- (see app, D). However, if an SPS program is bate. In light of past controversies over the pursued, further comparative analysis between siting of powerplants, transmission Iines and energy options would be required as more is other facilities, it is clear that environmental learned about the unquantifiable impacts that issues could play a key role in public consid- could not be incorporated in the present eration of SPS (see ch. 9). studies A good portion of this chapter dis- This chapter will outline the environmental cusses these latter effects for SPS. and health impacts of SPS that are currently The discussion in this chapter relies heavily thought to be most important. It will identify on the data and analysis generated by the De- research needs and highlight areas of con- partment of Energy (DOE)5 and the National troversy. As with other aspects of SPS, the en- Academy of Sciences (NAS). 6 7 The reader is vironmental effects have been evaluated most fully for the reference system. Some of this ——-. —— data is also applicable to the other SPS tech- 11 j Ha begger, J R Gasper, and C D Brown, Hea/th and Safe- tv Pre/lrnlrtary Cor-nparatlve Assessment of the Sate//ite Power nical options, differing only in extent or $vstem / SPS) and Other Energy Alternatives, DOE/NASA report degree, but information on the full range of No DO I IF R-0053, April 1980 their environmental effects is limited. ‘CI t Newsom and T D Wolsko, Pre/irnfnary Comparative As- SCJS smen t o t Land Use for Satellite Power Systems and A Iternatl ‘.te At the current stage of development, SPS en- F /ectrlc t nergy Technologies, DOE/NASA report No [ )OE I R-0058, April 1980 vironmental studies can play an important role ‘D A Kellermeyer, C/imate and Energy: A Comparative Assess- in determining concept feasibility, technical ment of the SPS and Other Energy A /ternatives, DOE/NASA report design, and cost. For example, bioeffects re- No DO} F R-0500, January 1980 ‘F P Levine, M J Senew, and R R Clr[llo, Comparative search might influence the choice of frequen- Assessment of Environmental Welfare Issues Associated With the cy which, in turn, couId determine hardware \ate//lte Power System and Alternative Technologies, DOE/NASA design and Iand use. Thus, many of the effects report ho [)OE/E R-0055, April 1980 5Envlronmenta/ Assessment for the Sate//ite Power System Con- currently identified might be minimized by ap- cept Development and Evacuation Program, DOE/NASA report propriate choices of design. However, it is also No DOt /E R-0069, August 1980 possible that one or more risks might be iden- “Comrnlttee on Satellite Power Systems, National Research ( ounc!l Open Committee Meetings Jan 31-Feb 1, 1980, Apr tified in the development process that could 910, 1980, j U Iy 1-2, 1980, Oct 1-2, 1980 not be reduced to an acceptable level without ‘(’ H l>odge (rapporteur), Workshop on Mechanisms Under/y-

179 780 ● Solar Power Satellites referred to the DOE documents for more de- would be required before decisions could be tailed discussions. While those studies have made regarding the environmental viability of not identified any environmental reasons not SPS. What is not clear is how long it might take to continue with SPS development, it is very before our confidence in the resolution of evident that much more study and research some environmental impacts such as micro-

(continued from p. 179) wave bioeffects would be high enough to Ing Effects of Long-Term, Low-Level, 2450 MHY Radiation on make development or deployment decisions. Peep/e, organized by the National Re\ear( h (-ouncil, Committee on Satel I Ite Power Systems, E nvlrontmental Studms floard, Na As table 28 illustrates, there is a great diver- tlonal Academy of Sciences, July 17-17, 1980 sity of environmental and health impacts. Of

Table 28.—Summary of SPS Environmental Impacts

System component Occupatlonal health characteristics Environmental impact Public health— and safety and safety Power transmission b Microwave — blonospheric heating could — Effects of low-level —Higher risk than for disrupt telecommunications. chronic exposure to micro- public; protective Maximum tolerable power waves are unknown clothing required for density is not known — Psychological effects of terrestrial worker Effects in the upper microwave beam as weapon —Accidental exposure to ionosphere are not known —Adverse esthetic effects high-intensity beam in —Tropospheric heating could on appearance of night sky space potentially severe result in minor weather but no data mod if i cat ion — bEcosystem: microwave bioeffects (on plants, animals, and airborne biota) largely unknown; reflected light effects unknown — bpotential interference with satellite communicant ions, terrestrial communications, radar, radio, and optical astronomy

Lasers —Tropospheric heating could —Ocular hazard? —Ocular and safety modify weather and spread —Psychological effects of hazard? the beam laser as weapon are —Ecosystem: beam may possible incinerate birds and —Adverse esthetic effects vegetation on appearance of night — bpotential interference sky are possible with optical astronomy, some interference with radio astronomy —— Mirrors — bTropospheric heating —Ocular hazard? —Ocular hazard? could modify weather —Psychological effect of —Ecosystem: effect of 24- 24-hr sunlight hr light on growing — b Adverse esthetic effects cycles of plants and cir- on appearance of night cadian rhythms of animals sky are possible — bpotential interference with optical astronomy Transportation and space operation b Launch and recovery —Ground cloud might pollute —Noise (sonic boom) may — Space worker’s hazards: air and water and cause exceed EPA guidelines ionizing radiation possible weather modi- —Ground cloud might affect (potentially severe) HLLV fication; acid rain air quality; acid rain weightlessness, life PLV probably negligible probably negligible support failure, long b COTV — Water vapor and other — Accidents-catastrophic stay in space, Ch. 8—Environment and Health ● 181

Table 28.—Summary of SPS Environmental Impacts—Continued —— — System component Occupational health characteristics Environmental impact — Public health and safety and safety POTV launch effluents could explosion near launch construction accidents deplete ionosphere and site, vehicle crash, toxic psychological stress, enhance airglow. Result- materials acceleration ant disruption of com- —Terrestrial worker’s munications and satellite hazards: noise, trans- surveillance potentially portation accidents important, but uncertain — bpossible formation Of noctiIucent clouds in stratosphere and mesosphere; effects on climate are not known — bEmission of water vapor could alter natural hydrogen cycle; extent and implications are not well- known — bEffect of COTV argon ions on magnetosphere and plasmasphere could be great but unknown —Depletion of ozone layer by effIuents expected to be minor but uncertain —Noise Terrestrial activities Mining —Land disturbance —Toxic material exposure —Occupational air and (stripmining, etc.) —Measurable increase of water pollution —Measurable increase of air and water pollution —Toxic materials exposure air and water polIution — Land-use disturbance —Noise —Solid waste generation —Strain on production capacity of gallium arsenide, sapphire, silicon, graphite fiber, tungsten, and mercury

Manufacturing —Measurable increase of —Measurable increase of —Toxic materials exposure air and water pollution air and water pollution —Noise —Solid wastes —Solid wastes — Exposure to toxic materials— Construct ion —Measurable land —Measurable land —Noise disturbance disturbance —Measurable local —Measurable local increase —Measurable local increase increase of air and water of air and water pollution of air and water pollution pollution ——.. —Accidents b Receiving antenna — bLand use and siting— — Land use— reduced — Waste heat major impact property value, esthetics, — Waste heat and surface vulnerability (less land roughness could modify for solid-state, laser weather options; more for reference and mirrors) b High-voltage — bLand use and siting— — bExposure to high light intensitity — Exposure to high transmission lines major impact EM fields—effects intensity EM fields— b (not unique to SPS) — Ecosystem: bioeffects of uncertain effects uncertain powerlines uncertain al mpacts based on sps systems as currently defined and do not account for offshore rece!vers or possible mitigating sYStem rnodificatlons bResearch priority. SOURCE: Office of Technology Assessment 182 ● Solar Power Satellites

most concern are: 1) the biological effects of Table 29.—Major SPS Environmental Uncertainties electromagnetic radiation produced by the Reference and solid-state systems power transmission and distribution systems; ● Microwave bioeffects - 2) the atmospheric effects of electromagnetic —Low-level, chronic exposure ● Launch effluent effects radiation and launch effluents and the re- —Ions in the magnetosphere sulting impacts on telecommunications and air —Natural hydrogen cycle quality; and 3) the land requirements and siting —Ionospheric depletion —Noctilucent clouds considerations for ground-based receivers. The ● Microwave heating of the ionosphere greatest environmental uncertainties are Iisted Effects on telecommunications ● in table 29. Land use Laser system ● Laser bioeffects The first part of the chapter will deal with . Tropospheric heating the potential environmental impacts resulting ● Launch effluents from the construction and operation of SPS • Land use systems. These and other effects will then be Mirror system ● Weather modification addressed in the second section as they pertain • Land use to human health and ecosystems. Detailed dis- ● Biological and psychological effects of 24-hr light cussion of a number of impacts is found in ap- Systems comparisons pendix D. SOLi~~E Of~c;of Technology Assessment

ENVIRONMENT

One of the consequences of constructing couId deplete portions of the ionosphere, alter and operating an energy system in space is that the natural hydrogen cycle and magneto- the extent of the environment that is directly sphere dynamics and modify weather and air affected by the system is much broader than quality near the launch site. The effects of the for Earth-based powerplants. For example, power transmission system on the atmospb” both the transmission of SPS power and the in- are a function of the frequency of the jection of launch effluents will directly affect For the laser and mirror systems, the mo~ every layer of the atmosphere. The purpose of nificant potential impact is heating of this section is to discuss the state of knowledge near-Earth atmosphere, which might alter of the predominant environmental impacts of weather. If the microwave beam were to alt SPS, especially those that are fairly unconven- the ionosphere, it couId disrupt telecom tional and to outline areas where further re- mu n i cat ions. search would be needed. Biological effects, i.e., human health and safety and ecological In order to understand clearly these and the impacts, are deferred to the second part of the other more conventional environmental im- chapter. pacts described in this chapter, it is worthwhile to review the properties and structure of the The two major environmental concerns at atmosphere as illustrated in figure 30 and dis- the present time are: 1 ) the effect on the at- cussed in box A. mosphere of the transportation and power transmission systems; and 2) electromagnetic interference with communications systems Power Transmission Effects on and astronomy.8 With respect to the former, the Atmosphere and Weather the effluents emitted from the launch vehicles Current SPS designs transmit energy to Earth using microwaves, lasers or reflected light. 8Program Assessment Report, Statement of Findings, Satellite Power Systems Concept Development and Evaluation Program, Since the atmospheric effects of power trans- DOE/NASA report No DO E/E R-0085, November 1980 mission are highly frequency dependent, each

Ch. 8—Environment and Health ● 183

Figure 30.— Regions of the Atmosphere

Solar radiation excites, disassociates and ionizes atmospheric constit- uents. The ionosphere in particular is a region of marked abundance of free electrons and ions. The properties of the ionosphere vary with latitude, time of day, season and solar activity. When electromagnetic waves enter the ionospheric plasma, they will be refracted and slowed down. Depend- ing on the frequency of the incident wave and properties of the ionosphere, the wave can be totally reflected. It is this phenomena that makes many radio frequency communication systems possible. 100

Regions of the atmosphere

SOURCE: Program Assessment Report, Statement of Satellite Power Systems Concept Development and Evaluation Program, DOE/NASA Report, November 1980 of these will be discussed separately. Table 30 mosphere. While attenuation of the micro- summarizes the impacts of most concern. wave beam by clouds and rain in the troposphere could cause a slight modification of Microwaves’ cloud dynamics and precipitation,9 absorption

As the beam from a microwave satellite traveled towards Earth, it would heat the at-

784 • Solar Power Satellites

Table 30.—Power Transmission Impacts of microwave energy is most important in the ionosphere. Of particular concern are the ef- Microwaves Upper ionosphere telecommunications effects unknown; fects of ionospheric heating on telecommuni- experiments and improved theory are needed cation systems that rely on the ionosphere to Lower ionosphere impacts are thought to be negligible transmit and reflect radio waves. Changes in for a number of telecommunications systems; scaling laws must be verified and effects on telecommunication the ionospheric properties due to heating can systems operating in the 3 MHz to 20 MHz range must be degrade (or in some cases, enhance) the per- tested formance of telecommunication systems by The maximum power density for which telecommunications effects are insignificant is not known and must be absorbing or scattering the radio signals (see determined fig. 31). Specifically, these effects could result Tropospheric heating is not thought to be significant in losses, fading, and scintillation of the elec- Lasers tromagnetic signals. It is also possible that the ● Thermal blooming in the troposphere may degrade the beam SPS pilot beam itself could be affected by the ● Tropospheric heating may cause increased cloud forma- heated ionospheric layers. tion, turbulence and weather modification ● Effects on the mesosphere, stratosphere, and thermosphere and continental cloud distribution and albedo In the course of the DOE assessment several are thought to be inconsequential experiments were conducted to test the extent Reflected light of heating and the effect on telecommunica- ● Weather modification in vicinity of ground sites is possi- tions in the lower ionosphere. These experi- ble, but unquantified . Photochemistry of the ozone layer is not thought to be af- ments demonstrated that while heating does fected occur the effects are not serious for the tele-

SOURCE: Office of Technology Assessment.

Figure 31 .—Examples of SPS Microwave Transmission Effects on the Ionosphere and Telecommunication Systems

F-region

ion

SOURCE: Prograrn Assessment Report, Statement of Findngs, Satellite Power Systems Concept Development and Evalua- tion Program, DOE/NASA Report, DOE/ER-0085, November 1980 Ch. 8—Environment and Health ● 185

communication systems tested. Some retain. In order to test these theories, the ground- searchers have even suggested that the pro- based heating facilities will have to be up- posed power density of 23 mW/cm2 could be graded doubled without significant impact to telecommunications in the lower ionosphere. In sum, it appears that effects on telecom- However, more research is needed in order to munications in the lower ionosphere would determine the power density threshold in the probably be negligible, but more study of the lower ionosphere, and for this the power densi- upper ionosphere effects is needed. By making ty of the existing heating facilities will have to the heating facilities more powerful, the fol- be increased. Additional study is also required lowing research can be conducted: to ascertain the effects in the lower ionosphere on telecommunication systems that operate at ● Lower ionosphere: verify scaling theory; frequencies greater than 3 MHz (i.e., 3 to 100 and test additional telecommunication MHz) range. In addition the effects of multiple systems (e. g., VHF, UHF, satellite-to- microwave beams need to be determined. ground)

Our knowledge of upper ionosphere (F re- ● Upper ionosphere: refine and verify F- gion) heating is less advanced than in the D & E region scaling laws and ionospheric phys- regions. Few underdense experiments (i. e., the ics and then test effects on representative beam travels through the region as opposed to telecommunications systems for SPS being reflected, which is termed an overdense equivalent heating. condition) to simulate SPS heating have been attempted. Recent experiments’ 2 suggest that ionospheric irregularities can be created when Lasers the Platteville heater operates in an underdense mode and that these irregularities in- The most significant potential environmen- duce scintillations in very high frequency satel- tal effects associated with the SPS laser system Iite-to-aircraft and satellite-to-ground trans- appear to be local meteorological changes and mission links. Further work would be required, beam spreading due to tropospheric heating. however, to establish whether scintillations would occur if SPS heated the upper iono- Tropospheric heating would result from sphere. Presently, the theoretical scaling energy absorption by aerosols and molecules models that would extrapolate these results to and from the dissipation of receptor waste SPS conditions in the F-region are very uncer- heat. Attenuation by scattering from molecules and by absorption and scattering from aerosols would be greatest for short wave- IOEnvironmental Assessment for the Satellite Power System – Concept Development and Evaluation Program – Effects of iono- lengths. Thus scattering would be only signifi- spheric Heating on Telecommunications, DOE/NASA report No cant for visible wavelength lasers, while aero- DO E/ ER-10003-Tl , August 1980 sol effects become important to infrared lasers 1‘W E Gordon and L M Duncan, “Reviews of Space SC I- ence — SPS Impacts on the Upper Atmosphere, ” Astronautics and only under hazy or overcast conditions. Aeronautics, VOI 18, No 7,8, July/August 1980, p 46 ‘ 2 S Basu, A L, Johnson, J A Klobuchar, and C M Rush, “Pre- liminary Results of Scintillation Measurements Associated With The absorption of laser energy would lead to Ionosphere Heating and Possible Implications for the Solar Power Satellite, ” Ceophysica/ Research Letters, VOI 7, No 8, a process called “thermal blooming, ” in which August 1980, pp 609-612 a density gradient acts as a gaseous lens that

83-316 0 - 81 - 13 186 ● Solar Power Satellites

can spread, distort or bend the laser beam.13 ing the water from aerosol droplets. After pass- The severity of the thermal blooming would be ing through the beam, the cloud fog would a function of several parameters, including the recondense. Portions of noctilucent clouds in frequency and intensity of the laser, the wind the mesosphere might also be vaporized. The velocity, atmospheric density, absorption and possible environmental consequences, such as altitude. Laser wavelengths that have high at- alteration of the continental cloud distribution mospheric transmittance would be less likely or albedo, would be slight but research would to suffer from thermal blooming. Thermal stiII be needed. blooming could also degrade and spread the Preliminary analysis indicates that the po- beam. It is clear that if spreading did occur it tential impacts in other atmospheric regions would be less critical for the space-to-Earth would be negligible. 18 In the stratosphere, SPS beam than for Earth-to-space transmission ozone would not be affected for wavelengths (i.e., laser pilot beam) that would be deflected greater than 1 micron. Possible perturbations earlier in its path. of the plasma chemistry by the laser beam in Tropospheric heating would be likely to in- the mesosphere and thermosphere are be- duce meteorological alterations. It is unlikely lieved to be small and inconsequential, since that global climate changes could result since the interactions would be confined to the laser the absorption of laser energy would be less beam volume; ionospheric heating would also than the typical natural variations of the at- be negligible. ” However, research would be mosphere; it would take the deployment of needed in order to validate this conclusion. 200,000 to 400,000 laser systems before the In the near term, environmental studies global climate might be affected. ” The poten- could concentrate on the following areas: tial local weather effects include changes in wind patterns, evaporation of sections of Ž Thermal blooming — increase theoretical ground fogs and clouds and elevated tempera- understanding and refine models; in- tures. None of these effects are expected to ex- vestigate enhancement of thermal bloom- ceed those associated with conventional nu- ing by clouds; study transmission and ther- clear powerplants of comparable power mal blooming as a function of laser fre- rating. ’5 The most significant potential impact quency, time of year, and receptor al- would be updrafts above the receptor site, titude and location. which might induce cloud formations (a prob- ● Induced clouds–study the extent and lem for the beam) and severe turbulence in the consequences of induced clouding. lower troposphere. Increased turbulence is not necessarily an adverse effect; the upward con- Reflected Light vective air movement would promote vertical The mirror system would reflect about 0.8 mixing and the dispersal of waste heat. 16 How- kW/m2 of light to Earth, somewhat less than ever, the turbulence could present a hazard to the illumination due to the Sun.20 The primary aircraft that flew in the affected region. For atmospheric effect of this additional light this and other reasons, it has been suggested would be tropospheric heating. Coupled with that aircraft be restricted from flying through the sensible heat release at the energy con- transmission areas. 7 version site, the weather might be measurably The laser beam would be capable of boring modified as convection, cloud formation, and holes through thin clouds and fog by evaporat- —— .— ‘“t Li Wa Ibrlclge, La$er %te//lte f>ower ~y$tem~, Argonne Na- 13R E Beverly, Sate//ite Power Systems (SPS) Laser Studies, t Iona I I aboi-atory, AN L E S-92, January 1980 Technical Report–Laser Environmental Impact Study, VOI 1, ‘“llt’k erly, op clt Rockwell International report No SSD 80-0119-1 “K W’ BI I I man, W P G Ilbreatll, and S W Bowen, “ Solar “Ibid I nergy 1 c onornlcs Orbltlng Reflector~ tor World Energy, ” In ‘Slbld I+o;t h’1~ ,]nd $tI// Beautlfu/ A4acro-Fngineerlng Revisited, F P “[bid Davidson, et al (eds ) (Boulder, Colo American A$soclatlon for “Ibid. I he A(ivancement of Science, We>tvlew Pre\$, 1980), PP 2~3-3 J9 Ch. 8—Environment and Health ● 187

rainfall above the site are increased. While no potential photochemistry effects if dichroic assessment has been made of the magnitude or mirrors were used in space. 25 consequences of this potential impact, the More detailed study is required before rea- weather effects of other “heat islands” of the sonable comparisons can be made between same scale, such as New York City that re- 2 the mirror system and the other SPS technical leases about 0.6 kW/m of heat, can be used options. Research priorities include: for comparison. ” Weather impacts on a global scale are not anticipated since the mirror ● weather modeling and large-scale com- system would add less than 0.015 percent to putations applicable to large mirror sys- the normal solar heat input. 22 Large-scale com- tem size, putations on weather models applicable to the ● the effects of dichroic mirrors on the sys- mirror system size are needed to quantify the tem’s environmental impacts, and effects for different locations. Additionally, ● possible ground-based experiments to the heating effects of the orbiting refiector simulate mirror system heating. system could be simulated on the ground, using solar heated ponds or other means Space Vehicle Effects* without the need for a demonstration satellite and hence at a relatively low cost and at an There are two major environmental effects early time. 23 associated with the space transportation segment of SPS: the injection of rocket exhaust Once the potential weather impacts are products into the atmosphere (see fig. 32) and more clearly understood, the system design noise generated at the launch site (see Health and economics could be reevaluated to ac- and Ecology). The severity of these impacts commodate possible environmental concerns. would depend on the size and frequency of For example, one might redesign the system to launches, as well as the composition of rocket reflect less Iight to Earth or use heat dispersion fuels and fIight trajectory. devices on the ground and in space to reject the heat into areas that would have the mini- Assessment of the potential SPS effects on mal impact. Dichroic mirrors in space for ex- the atmosphere is hampered by the unprece- ample, could selectively reflect to Earth only dented scale of SPS transportation require- those wavelength bands that would be con- ments as well as an incomplete understanding verted with highest efficiency at the receiving of the atmosphere. The reference design, for site. It may also be found that the weather example, requires that a heavy lift launch vehi- modification induced by the mirror system cle (HLLV), five times larger than the Saturn V, heat is actually beneficial to the receiving re- be flown one to two times per day for 30 gion by preventing cloud impingement over years.”) The other reference system space vehi- site. cles and launch schedules are shown in tables 31 and 32. In addition to tropospheric heating, other possible environmental impacts have been The effects of SPS exhaust products on the suggested. The mirror system beam might per- atmosphere are also uncertain because much turb the photochemistry of the atmosphere, of our theory and experience with the effects particularly the ozone layer. However, pre- of launch effluents stem from the space shut- liminary analysis indicates that the effect tle, which uses solid-fuel boosters. Since the would be negligible.24 Further study is needed SPS HLLV would be fueled with liquid propel- to confirm this finding and to investigate the lants, the composition and distribution of the

‘ 1 Kenneth f31 I I man, E PR 1, Private ( ommun I( atlon “K BII I man, W P G Ilbreath, S W Howen, “Solar t ner,gy Re- - ‘ 1+1 I In)(i n, private ( ommu n 1( at Ion vlslted W Ith Orbit Ing Ref Iector$, N A 5A, A me\ J(’t’ ,1 1)1) [ ) tor (l(~ta I Is ‘‘f311 I man, private commun Icatlon ‘ / II L ~r(]nm(~n(,]/ ! >~c~~ment for the $ate//Itc Power ‘iy~tem “BII I man, G Ilbreath, and Bowen, Solar Energy F conom I( ~, ‘ ( ( )n( f>p( 1 )fII f]/oprrrcnt ,] nc] F ~ .I /[Ia (Ion Prcj#r,]m, [JOE E R-()()()!), Op (-It A[lgu\t 1‘)80 188 ● Solar Power Satellites

Figure 32.—Summary of SPS Atmospheric Effects reference system launch effluents would differ from that of the shuttle.

The major space vehicle impacts of the ref- Alteration of erence system are identified in table 33. Pres- satellite environment ently, the greatest uncertainties are associated Alteration of plasmaspheric with four potential effects27 (treated in more and magnetospheric LEO to GEO populations and dynamics detail in app. D): Orbit transfer people carrier> chemicals ● cargo carrier > ions I n the magnetosphere, the emission of ions from COTVS and POTVS would substantially increase the ambient concen-

Ionospheric depletion trations of these particles. Because of our poor understanding of the complex dynamics and composition of this region, potential impacts can be identified, but the likelihood and severity of these effects are highly uncertain. Possible effects include enhancement of Van AlIen belt radiation and changes in magnetospheric and plasm aspheric dynamics that could perturb ionospheric electricity, tropo- o spheric weather, and satellite communi- cat ions. SOURCE: Environmental Assessment for the Satellite Power System Concept Development and Evaluation Program, DOEI/R-0069, August 1980. —— — ‘Pro~r,]m As~e\\ment Report, $tatement o F~ndin,q\, op clt

Table 31 .—SPS Space Transportation Vehicles

Launches b Operating Main exhaust Name Function Propellants per year altitude (km) products c Heavy-lift Transport CH4/O2 (stage 1) 375 0-57 C02, H20 launch vehicle material H 2/02 (stage 2) 375 57-120 H 20, H2 (HLLV) between Earth H2/O2 (circular- 375 450-500 H 20, H2 and LEO ization/deorbit) Personnel Transport Details not 30 0-500 C 2, H20, H2 launch vehicle personnel available (PLV) between Earth (probably same and LEO as HLLV) Cargo orbit- Transport Argon 30 500-35,800 Ar+ plasma transfer vehicle materials H 2/02 H2O, H2 (COTV) between LEO and GEO Personnel orbit- Transport H 2/02 12 500-35,800 H2O, H2 transfer vehicle personnel (POTV) between LEO and GEO . %HJOZ: liquid methanelliquid oxygen HJOZ: liquid hydrogenlliquid oxygen. bAssuming construction of two (silicon option) 5-Gw satelliteslyear. CCOZ: carbon dioxide HzO: water H,: hydrogen Ar + : argon ion. SOURCE: Environmental Assessment for the Satellite Power System Concept Development and Evaluation Program, DOE/ER-0069, August 1980, Ch. 8—Environment and Health Ž 189

Table 32.—Exhaust Products of SPS Space Transportation Vehiclesa

Altitude Total Atmospheric range mass Mass of specific emission products (t) b c region (km) Source (t) C0 2 co H 2 O H2 Ar + Troposphere 0-0.5 HLLV, PLV 650- 260 117 260 13 — 0.5-13 HLLV, PLV 2850 1140 513 1140 57 — Stratosphere 13-50 HLLV, PLV 3027 1210 546 1210 61 — Mesosphere 50-80 HLLV, PLV 758 199 90 450 19 — Thermosphere 80-125 HLLV, PLV 2031 — — 1960 71 — LEOd HLLV, PLV 33 — . 443 1— LEO POTV 460 — — 443 11 — Exosphere GEOd POTV 153 — — 147 6— 477-GE0 COTVe 985 — — 0 0 985f

aMass emissions per flight. bpLV emissions would be ~hemi~all~ similar t. those of the l+LLV, but are not Otherwise determined at ttlls time. The numbers shown are emissions Of the HLLV OIIiy ct = metric ton = 1000 ‘g. dLow earth orbit (LEO) is at 477 km; geosynchronous earth orbit (GEO) is at 35,800 km

eln addition t. mass emissions, the argon plasma en~lnes of the COTV would inject a significant amount of energy into this altitude range. Also ar90tl pla.sllla el19illeS would be used for satellite attitude control and stationkeeping control at GEO; these em Isslons are unknown at present and have not been included. fAr+ mass for the silicon Photovoltalc cell option For the gallium aluminum arsenide Opt!on, the Ar+ mass Would be 212 t. SOURCE: Environmental Assessment for theSatell)te Power System Concept Development and Evaluation Program,DOEIER-0069, August 1980.

Table 33.—Space Vehicle Impacts ● The injection of water vapor in the upper atmosphere would significantly increase Troposphere ● Ground cloud nuclei and heat could have a measurable the water content relative to natural lev- effect on weather els. One possible consequence is an in- ● NO emissions are small compared to typical powerplant, X crease in the upward flux of hydrogen but in conjunction with ambient concentration could exceed projected EPA standards atoms through the thermosphere. If an Stratosphere and Mesosphere accumulation of hydrogen results, the ● aEmission of water vapor may cause noctilucent clouds dynamics of the thermosphere and ex- in the mesosphere; climatic effects would probably be osphere could be affected. Satellite drag small, but uncertain a could also be increased. Models of the . Water and NOX are not expected to significantly alter ozone, but uncertainties remain natural hydrogen cycle are needed to Ionosphere a quantify and simulate the effects of SPS ● Formation of large ionospheric hole in F-region from on global scale. water and other effluents should not adversely affect HF telecommunication signals over distances significantly ● The injection of rocket exhaust, particu- larger than the ionospheric depletion, impacts on other larly water vapor, into the ionosphere telecommunications systems are not known; more studies are needed; long-term depletion around launch could lead to the depletion of large areas trajectory possible of the ionosphere. These “ionospheric a ● D&E region effects are poorly understood; impacts on holes” could degrade telecommunication telecommunications from depletion of the ionosphere are possible systems. While the uncertainties are ● Possibility of enhanced airglow and Perturbation of Van greatest for the lower ionosphere, ex- Allen belts, but likelihood is-unknown’ periments are needed to test more ade- Thermosphere and Exosphere a quately telecommunications impacts and ● Large increase in water content might alter the natural hydrogen cycle and affect the dynamics of the region to improve the theoretical understanding Plasmasphere and Magnetosphere of chemical-eIectricaI interact ions ● aArgon ions and hydrogen atoms might enhance Van throughout the ionosphere. Allen belt radiation, generate ionospheric electric currents that would interfere with public utilities, modify ● Another consequence of increasing the auroral response to solar activity and affect weather and concentration of water in the upper at- satellite communications, but probability and severity are mosphere might be the formation of noc- unknown ● The effects of the satellite structures are thought to be tilucent clouds in the mesosphere. While negligible or easily remedied global climatic effects of these clouds are aResearch priorities. thought unlikely, uncertainties remain, SOURCE: Office of Technology Assessment especially with respect to the persistence 790 ● Solar Power Satellites

of the clouds as a function of tempera- cles. 29 While the economics and technical ture. feasibility of this concept have been evaluated, the possible environmental impacts The transportation system for other SPS op- have not been studied and require consid- tions could be substantially different from that eration for the reference system. For example, the mirror system and the bulk of the laser system satellites operate in low-Earth orbit (LEO). The Electromagnetic Interference magnetospheric effects associated with trans- Each SPS transmission option, whether porting materials to geostationary orbit (CEO) microwave, laser, or mirror, has the potential would therefore not be a problem for these for affecting other users of the electro- systems. Environmental impacts are also deter- magnetic spectrum. In general, where such ef- mined by the frequency of launches, which fects occur they will be detrimental to one user depends on the size of the vehicle, and the or another, since most systems now depend on total mass in orbit. For the same size launch the relative purity of the wavelength band they vehicle and total system power, it appears that use. the mirror system, which is the least massive per kilowatt of the four alternatives, would re- Sharing the same air or ground space is pos- quire the least number of flights, whereas the sible by operating at different frequencies and laser system would require the most. at specified power levels. This is most obvious for radio frequencies, where the frequency Other transportation scenarios have been band width and power levels at which systems proposed (see ch. 5). With respect to the can operate are assigned by national agencies reference system, some of the environmental working in accord with national and interna- effects could be mitigated by changing the tional standards. Where potential for inter- flight trajectory of the HLLV, the rocket fuel of ference occurs in the radio frequency spec- the COTV or other transportation characteris- trum, the power level and antenna character- tics that present a problem. Laser propulsion, istics of such interference are strictly regulated for example, has been suggested as an option. in order to keep it below the available technol- The tradeoffs associated with these design ogy’s ability to filter out undesirable effects. changes would need to be studied as the SPS The principle is to assure that electronic sys- concept evolved. tems are compatible with one another, i.e., As an alternative to the HLLV, it has been that interference from one system does not argued that economies of scale result from degrade the overall performance of a second. increasing the number and frequency of Because of the large amounts of power that launches of a vehicle much smaller than the the microwave, laser, or mirror SPS systems 28 proposed HLLV. However, it is not clear how transmit through the atmosphere, and the ex- the effects of more launches of a smaller tensive area covered by a full satellite de- rocket compare to the impacts of fewer flights ployment, potential interference effects would of a larger one. be much greater than any other system which A very different approach in the construc- now use the electromagnetic spectrum. They tion of SPS wouId be the utilization of nonter- would also be commensurately more difficult restrial materials. This could significantly to ameliorate. Affected parties would include reduce the amount of terrestrial materials that users of space and terrestrial communications need to be transported to space, and hence and sensor systems, radar systems, various ter- reduce the environmental impacts associated restrial control devices, computers, radar and with the frequent launch of transport vehi- radio telescopes, optical telescopes, and

‘“D L Aklns, “Optlmlzation of Space Manufacturing Sy$- . terns, ” In Space Manufacturing From Non- Terre\ trla/ Materla/\, J ‘‘J (irev, $ate//lte Power $y~tem rechrrlca/ Optlons and Eco- Grey and C Krop (eds ) (New York Al AA, November 1979) non)l{ \ c ontractor report prepared for OTA, Nov 14, 1979 Ch. 8—Environment and Health ● 191

microprocessors. SPS systems using micro- compatibility with other spectrum users. waves for power transmission would generate Receivers also generally include sufficient fil- the greatest potential interference because tering to prevent degradation by the residual communications systems and passive receivers undesired signals. However, the magnitude of of alI sorts share this portion of the spectrum, the power level at the central frequency and in as well as other electronic equipment (e. g., harmonic frequencies for a microwave SPS computers, control devices, sensors) that are would be so great that the possibility of de- susceptible to microwave energy. The refer- grading the performance of CEO and LEO sat- ence system is designed to transmit at 2.45 ellite receivers is significant. Examples of seri- GHz, the center of the Industrial, Scientific, ous interference include the 2.50 to 2.69 GHz and Medical band (ISM). direct broadcast satellite band, the 7.3 to 7.45 GHz space-Earth government frequency slot,’” This analysis focuses on the affected users and the S-band National Aeronautics and on an area-by-area basis. It is based on the Space Administration (NASA) space communi- presumed characteristics of the three transmis- cations channel. sion options of table 34. However, it should be emphasized, that the precise characteristics of I n addition to the direct effects from micro- the transmission beams are as uncertain as wave power transmissions, geostationary com- other details of the proposed alternative sys- munications satellites may experience “multi- tems. Not only are the characteristics of the path interference” from geostationary power systems and their components poorly known, satelIites due to the latter’s sheer size. I n some the theory is inadequate to extend known data cases, microwave signals traveling in a straight to other frequencies, angles, or distances. Iine between two communications satellites Nevertheless, it is possible in most cases to in- wouId experience interference from the same dicate broadly the sources of potential in- signal reflected from the surface of the power terference and their effects on other users of satelIite lying between them. Communications the spectrum. satelIite uplink channels would be degraded by multi path interference from the SPS vehicle during orbit periods when the SPS is at a lower Potential Affected Users of the Electromagnetic Spectrum aItitude than the adjacent communications satelIites. SPACE COMMUNICATIONS These adverse effects would necessitate a All artificial Earth satellites use some por- limit on the spacing that a geostationary satel- tion of the electromagnetic spectrum, either lite must have from a power satellite in order for communication, remote-sensing or tele- to operate effectively. The minimum necessary metering data. All would be affected in some spacing would depend directly on the physical way by the SPS. design of the satellite, the wavelength at which it operates, the type of transmission device ● Geostationary satellites. These would be most strongly affected by the microwave sys- used (i.e., klystron, magnetron, solid-state tems. They would experience microwave inter- device), and the satellite antenna sidelobe ference from the fundamental SPS frequency magnitudes, transmitted power, orbit perturba- (e.g., 2.45 GHz for the reference design) and tions, and intermodulation product frequency noise side bands, spurious emissions in nearby distribution and amplitudes. bands, harmonics of the fundamental SPS fre- Because a microwave SPS as currently con- quency, and from so-called intermodulation figured must share the geostationary orbit with products. All radio frequency transmitters gen- other satellites, the value of the minimum erate harmonics and minor spurious components in addition to the desired signals. The “’John R Juroshek, “The SPS Interference Problem – Elec- tronic S} ~tem Effects and Mltlgatlon Techniques, ” The Final f’ro- unintentional outputs are fiItered to satisfy na- ceedlng~ ot the 5olar Power Satellite Program Review, Conf tional and international regulations about 800491 f[lOE), pp 411-438 192 ● Solar Power Satellites

Table 34.—Summary of Electromagnetic Effects

System Spectral region Affected systems Mechanism/effect Microwave Microwave ● Power radiation at central Terrestrial Scatter in atmosphere, from frequency (2.45 GHz or some rectenna other choice) LEO satellites Pass through SPS beams Radio astonomy receivers Scatter from rectennas, atmosphere Deep space communications Direct interference ● Harmonics of central frequency GEO satellites Direct interference Radio astonomy receivers Direct interference ● Spurious noise near central GEO satellites Direct interference Radio astronomy receivers Scatter from rectennas ● M u I i path interference GEO satellites Two-beam interference Infrared ● Thermal radiation from Radio astronomy receivers Direct interference (raised all satellite components background). Satellite appears as spurious source Infrared astronomy receivers Satellite appears as spurious source All wavelengths (reflected sunlight) ● Diffuse reflections ● Specular reflections Optical telescopes Sky background increased. Ž Glints Portions of sky obscured. Laser Microwave ● No discernible effect None Infrared ● Central beam radiation Infrared receivers near terrestrial receiver . Thermal radiation from all Radio astonomy receivers Direct interference (raised components background). Satellite appears as spurious source All wavelengths (reflected sun/ight) ● Diffuse reflections Optical telescopes ● Glints Probably no effect Mirrors Microwave ● No discernible effect None Infrared ● Thermal radiation from all Radio astronomy receivers Direct interference (raised components background). Satellite as spurious source All wavelengths (reflected radiation) ● Specular reflection to Optical telescopes near General sky brightening terrestrial station terrestrial station ● Diffuse reflection Optical astronomy Sky background obscured around satellite ● Glints from structural Effect probably small components

SOURCE: Office of Technology Assessment necessary spacing has emerged as one of the rameters that are needed in order to calculate most critical issues facing a geostationary SPS. the minimum required spacing. In addition, However, in the absence of a specific design, it even if the design parameters were known ac- is impossible to characterize the exact form curately, the theory of phased arrays is insuffi- and nature of the potential interference pa- ciently developed at present to predict the Ch. 8—Environment and Health ● 193

minimum spacing with any accuracy. Es- owing in the path from orbit to terrestrial timates range from ½0 to 10. 31 The lower Iimit station by the large SPS vehicles, and would probably be acceptable. However, a receiver interference thresholds that could minimum spacing much greater than 10 would, be exceeded by the unintentional emissions result in too few available geostationary slots from the SPS platforms. They use a range of to allow both types of users to share the orbit optical and microwave sensors, particle over the continental United States. detectors, computers, and communication devices. Although the optical sensors are not In 1980, some 80 civilian satellites shared damaged by a microwave beam, increased the geostationary orbit worldwide, and by 1990 device noise can result in microwave inter- that number is expected to increase substan- ference in related parts of the satellite. ” A tially. Even though improvements in technol- number of shielding and filtering techniques ogy will lead to a reduction in the total number are available to ameliorate potential inter- of satellites necessary to carry the same ference. These would need to be tested for volume of telecommunications services, total specific satellite and deployment scenarios. service demand is expected to rise dramati- Such satellites could protect their uplink cally. At present the minimum spacing for communications receivers from adverse in- domestic geostationary satellites is 40 in the terference by shutting down for that short 6/4 GHz communication band and 30 in the period (a few seconds) during SPS power 14/12 GHz band. At these spacings, a total of beam traversal, or it might be feasible for 90 6/4 GHz band satellites and 120 14/12 GHz the SPS to shut down for the satellite band satellites could theoretically coexist at passage. ” For short-term SPS shutdown, geostationary altitudes, in the absence of SPS. high-capacity battery storage would have to Additional satellites could use other frequency be Included in the ground segment (see ch. 9, bands without interfering with the above satel- sec B). This shutdown presents a severe con- lites, though this would ultimately be limited trol problem (reduce power, start up again), by the station-keeping capability of the vari- as well as serious network load transfer com- ous satelIites. Multiple use platforms represent plexities. It may also be possible for some one possible option to reduce contention over satellites to fly orbits that would not in- orbital spaces. tersect the SPS beam. For example, satellites The laser and mirror systems in LEO would traveling in an equatorial orbit at altitudes not interfere substantially with geostationary lower than 1,000 km would not intersect SPS satellites. Even in the unlikely event that such beams directed to rectennas at 350 latitude a satellite were to pass precisely between a or greater. Computer and processing/control geostationary satellite and its ground station, circuit functions can be protected by im- the time of passage as well as the apparent size proved module shielding and intercon- of the occluding power satellite would be so nection noise filtering. small as to cause only a slight diminution of The laser and mirror systems might interfere the signal. with nongeostationary satellites by causing ● Other satellites. In addition to geostationary reflected sunlight to blind their optical sensors satellites that would operate at the same or by occluding communications beams. Of altitude as the GEO SPS, there are numerous the two systems, the mirror system would be remote sensing, communications, and navigation satellites in various LEOs that may “W H Grant, E 1 Morrison, J r , and K C Davis, “The EMC pass through an SPS microwave beam. Pro- Impa[ t of SPS Operations on I.ow Earth Orbit Satellites, ” The posed high-Earth orbit (HEO) satellites I inal Pro( eeding~ of the Solar Power Satellite Program Review, would also be affected because of shad- Conf -80(M91 (DOF ), pp 411-434 ‘‘P K ( hapman, “ E ncounter$ Between SPS Power Beams and Satel Iitei In 1 ower Orbits, ” [he F\na/ Proceedings of the Solar ‘1 E Morrison, et al , SPS Effect$ on L[ ~) and GE() Sate//ite$, Power \,]te//lte Program Review, Conf -&100491 (DC) E), pp NTIA publication (In pres$) 4284 W 794 ● Solar Power Satellites

most problematic because of the large size of mit far better rejection of unwanted signals the mirrors and their orbital speed. To date, no than is now necessary. This appears to be tech- one has calcuIated the possible adverse effects nically feasible; primary concerns would be due to this cause. modifications to the shielding of sensitive circuitry. The initial estimate of the cost of modi- ● Deep space communications. Because deep fying terrestrial electronic equipment is in the space probes generally travel in the plane of range of 0.1 to 5 percent of the unit cost (ap- the solar system (known as the ecliptic), they proximately $130 million for the 1980 estimate would be especially affected by a geosta- of the inventory of susceptible equipment). tionary microwave SPS. As seen from the Earth, the ecliptic crosses the Equator in two The EMC evaluation program determined places. A microwave SPS would effectively that most terrestrial electronic equipment prevent ground communication with the would be unacceptably degraded by SPS inter- probe when the latter happens to lie near the ference for power levels possible within a 50- part of the ecliptic that crosses the Equator. to 75-km distance of a rectenna site. The most This interference is especially serious for sensitive equipment, such as high capacity deep space vehicles because it is essential to satellite terminals and radio astronomy re- be able to communicate with them at any ceivers would be adversely affected at dis- time for the purposes of orbit control and tances of 100 to 200 km. for timely retrieval of stored data. The Mitigation techniques have been evaluated susceptibility problem is more serious than for radars, computers and processors, sensors, normal satellite communications links be- and muItichannel terrestrial microwave com- cause of receiver sensitivities and the low munications. With the exception of the most signal-noise ratios imposed by the long sensitive receivers, modifying shielding and distances from Earth station to probe. grounding procedures and using rejection It would be possible to avoid such inter- filters in radar and communications receivers ference by establishing a communications would allow most systems to operate with the base for deep space probes in orbit. As we SPS interference levels expected at the recten- penetrate deeper into space, this may be ad- na site boundary. Special mitigation tech- visable for other reasons. Such a communica- niques for more sensitive systems involving in- tions station would effectively add to the cost terference cancellation methods have been of the SPS. considered, but they must be tested to determine the range of protection possible. TERRESTRIAL TELECOMMUNICATIONS AND ELECTRONICS EFFECT ON TERRESTRIAL ASTRONOMY Both civilian and military terrestrial tele- AND AERONOMY communications and electronic equipment None of the proposed SPS systems could wouId suffer from a number of possible effects benefit astronomical research except insofar of a microwave beam. Direct interference can as they would indirectly provide a trans- occur from the central frequency and har- portation system for placing large astro- monic emissions. In addition, scattered and nomical facilities in space. Their detrimental reflected radiation from the rectenna and effects would vary depending on the system structure intermoduIation products could chosen. The impacts of a microwave system cause additional interference problems for ter- would likely be severe for both optical and restrial receivers. At the very least, rectennas would have to be located far enough from crit- ‘1 Morrl\on, “SPS Susceptible Systems Cost Factors – lnvest- ical sites such as airports, nuclear powerplants, 111 ent 5 u (m m a ry and M It I gat Ion Cost I nc rernent E st I ma tes, ” I n and miIitary bases to render potential inter- l)res~ ‘P A t kstron and C M Stokes, “Work$hop on Satellite ference as small as possible. In addition, most I)ower ~y~tem~ (SPS) Effects on Optical and Radio Astronomy, ” equipment would have to be modified to per- ( ont 7’)05141 (DOE) Ch. 8—Environment and Health • 195

radio astronomy. An infrared laser system36 sky would be permanently blocked from would have fewer detrimental effects on both view. The relay satellites located in CEO forms of astronomy than the reference system. would not be Iikely to interfere with optical The mirror system would have its most serious observations. However, large moving sat- effect on optical astronomy. ellites would present optical astronomy with another observational obstacle. Scattered ● Optical astronorny. For the reference sys- light from them would vary in intensity as tem, diffuse reflections from the satellite the satellite passes near a celestial object of structures would cause the greatest degra- interest, making calibration of the nearby dation for terrestrial telescopes. Because background radiation very difficult if not they appear to remain stationary along the impossible. Photographic exposures of faint celestial Equator, reflected Iight from a sys- celestial objects may last from 1 to 3 hours tem of 15 to 60 satellites would meld to- and individual photographs cannot be gether to block observation of faint objects added effectively. The laser satellite would over a large portion of the sky near the interfere with infrared astronomy studies in- Equator for telescopes located between the volving wavelengths adjacent to the trans- longitude limits of the satellites. Some mission wavelength of the beam. major foreign, as well as most domestic ob- The mirror system, which would involve a servatories would be affected. Observations number of large, highly reflective moving of bright objects would be possible, but de- mirrors in LEO, wouId have very serious graded in quality. In addition, reflected light effects on optical astronomy. While the pre- from the LEO construction base could be ex- cise effect has not been calculated, it would pected to interfere with observations of render a large area around the ground sta- faint sources in its vicinity. Telescopes in tions totally unacceptable for telescopic orbit, such as the U.S. Space Telescope, to viewing. Because of diffuse reflections from be launched in 1984, will travel in nonequa- the atmospheric dust and aerosols above the torial orbits and therefore would not be ground station, the individual mirrors would affected significantly by a reference system create moving patches of diffuse light that SPS. The danger of pointing directly at a would preclude studies of faint objects that geostationary satellite will increase the com- lie in the direction of the satellite paths. plexity of the telescope-pointing mech- Radio astronomy. Radio astronomy would anism. Astronomical photometry and spec- suffer two major adverse affects from micro- trometry instrumentation, and high res- wave systems: 1) electromagnetic interfer- olution telescope tracking systems would be ence from the main PS beam, from harmon- degraded if located within 50 to 60 km of a ics, from scattered or reflected SPS signals, rectenna site. The EMC evaluation program and from reradiated energy from rectennas; indicated the necessity of improving sensor and 2) increasing the effective temperature and sensitive circuit shielding, and main- of sky noise background, which has the ef- taining a minimum separation distance of 50 fect of lowering the signal-to-noise ratio of to 60 km between rectenna sites and tele- the radio receivers. Studies of faint radio ob- scopes using sensitive electronics to remove jects near the Equator would be rendered SPS induced degradation. impossible. In addition, rectennas would The effect of diffuse reflections from a have to be located more than 200 km from laser SPS in LEO could be expected to cause radio observatories and in terrain that would fewer problems for observations of diffuse shield the observatories from reradiated objects near the Equator because the laser microwave energy. Also of concern to radio collection and transmission satellite would astronomers is the possibility that expected be constantly in motion. Thus, no part of the failures of the klystron or other microwave emitting devices would resuIt in spurious

‘“C Baln, Potential of Law for 5P$ Power rran$ml$~lon, SPS noise signals that would further disrupt CDEP, October 1978 radio astronomy reception. 196 ● Solar Power Satellites

Neither the laser nor the mirror systems Terrestrial Activities would contribute to the first effect. However, they would raise the effective temperature of The terrestrial environment would be af- the sky background. Low-level measurements fected by SPS in a number of ways. The con- such as scientists now routinely conduct, for struction and operation of receivers could example, to measure the amount of back- alter local weather, land use, and air and water ground radiation from the primordial explo- quality. The mining, manufacturing, and trans- sion of the universe would thus be extremely portation associated with SPS could also 37 difficult if not impossible from terrestrial sta- adversely affect the environment. tions. Many other types of sensitive radio astronomy observations would be seriously Land Use and Receiver Siting degraded. Land use and receiver siting are important The susceptibility of radio astronomy re- issues for SPS, especially from a political ceivers results from their high sensitivity, and perspective (see ch. 9, Issues Arising in the the wide range of observing frequencies in the Public Arena).* This is due in part to the microwave spectral region. Mitigation tech- microwave and mirror system land require- niques effective for other electronic equip- ments for large contiguous areas for receiving ment are only marginally useful because of the stations and transmission lines. In siting sensitivity factor and associated dynamic receivers, tradeoffs wouId have to be made be- range. A preliminary review of interference tween a number of parameters such as the to- canceling techniques indicates that this pography and meteorology of the candidate method has a high probabiIity of providing re- locations, local population density, land and jection of SPS signals to a level that would transmission line costs, electromagnetic in- allow rectenna sites to be located within a 100- terference, and electricity demand, as well as to 150-km range from radio astronomy fa- environmental impacts. The construction and cilities. Detailed design and testing at a radio operation of SPS receivers wouId have measur- astronomy receiver is necessary because of the able effects on the ecology, soil, air and water 38 unique aspects of integrating a canceler func- quality, and weather of the receiver area. tion into such complicated and sensitive Since many of these impacts are site-specific, receivers. an extensive program wouId have to be carried out in order to locate and assess each pro- Space basing of radio telescopes, especially posed site. on the far side of the Moon, would eliminate the impact of SPS and other terrestrial sources The severity and extent of the environmen- of electromagnetic interference. However, tal impacts of SPS ground receivers and trans- such proposals, though attractive from the mission lines would also depend on which SPS standpoint of potential interference, are un- system is deployed. For example, as shown in likely to be attractive to astronomers for many table 7, the baseline mirror system (1) would decades because of their high cost and relative deliver power to a few, extremely large sites, inaccessibility. whereas the laser system might be designed to

● Optical aeronomy. Much of our knowledge of the upper atmosphere is gained by night- “5ate//lte Power System, Concept t3evelopment and Eva/ua- time observations of faint, diffuse light. tlon Program, reference system report, DOE/E R-0023, October Some of the observations that are made to- 1978 day must be carried out in the dark of the ‘The majority of remarks made In this section pertain to land- based receiver sites as specif]ed by the technical systems ad- Moon. The presence of satellites whose in- ciressed In this report It IS Important to note, however that off- tegrated brightness is equal to a quarter ~hore receptor sltlng that may alleviate some of the problems Moon would effectively end some studies of ,) ~soc Iated with land-based s Ites IS a I so possible ‘“ fnbjronmental Assessment for the Satelllte Power System the faint airglow and aurora. Other observa- ( oncepf lleve/opment and Eva/uatJon Program, DOE’E R-0069, tions would be severely limited in scope. Augu~t 1980

Ch. 8—Environment and Health ● 197

generate the same amount of power at a great Figure 34.—Microwave Power Density at Rectenna number of sites, each of which is two to three as a Function of Distance From Boresight orders of magnitude smaller than the mirror sites. Smaller mirror system (1 1) sites are also 2.45 GHz possible. 50 23 mW/cm2 For safety purposes, buffer zones would be established around each site. For the laser design, the infrared power density at the edge 10 of this zone would be 10 mW/cm2 (see fig. 33). As shown in figure 34, the microwave power 5 density at the edge of the reference system exclusion boundary would be 0.1 mW/cm2. If microwave standards become considerably more stringent, SPS land requirements could in- 1.0 crease. For example, if the power density at the edge could not exceed 0.01 mW/cm2 (the Soviet standard), then each site would require almost 1,700 km2 of land.39 In addition to land for receivers, about 20 to 850 km2 would be needed for launch facilities.40 This could be made available through expansion of the Kennedy Space Flight Center

“J B Black burn, Power Mapping of for DOE/NASA Report HCP/ R-4024-10, October 1978

.01

Figure 33.— Receptor Site Protection Radius as a Function of the Perimeter Laser Power-Density Level .005

.001 o 5,000 10,000 15,000 20,000

Ground radius, m

SOURCE Satellite Power System, Concept Development and Evaluation Pro- gram, reference system report, DOE/ER-0023, October 1978.

in Florida, although environmental considerations might preclude this option. Transmission line, mining, and transportation land uses are not considered in table 35. More analysis is 10’ needed to determine these impacts and to ex- 10-3 10– 2 10- ‘ 10” 10’ plore tradeoffs between centralized and dis- Perimeter power density, W/cm2 persed electricity systems with respect to transmission line siting. In table 36, the SPS ref- SOURCE: R. E. Beverly, Satellite Power Systems Laser Report—Laser Environmental vol. erence system is compared to other electricity Rockwell International report, SSD 80-0119-1. powerplants. 198 ● Solar Power Satellites

Figure 35. —Rectenna/Washington, D.C. Overlay The taper of the solid-state power-transmission system makes offshore siting particularly attractive. A few preliminary technical studies have been conducted,” including an offshore rectenna siting study,42 (see fig. 36). However, little attention has been paid to the environmental ramifications of offshore siting. Areas of special concern include the effects on weather and ecosystems from thermal release and the effects of microwaves on aquatic life and birds that might be attracted to the receiver

Land-use problems might also be alleviated by innovative receiver designs that would permit multiple land use under the receivers, such as crop agriculture, biomass production and aquaculture.43 Again, however, until the biological effects of microwaves and reflected sun Iight are better understood, the environmental impacts and hence viability of these

Washington , D C ideas are largely unknown.

SOURCE: Office of Technology Assessment.

Some of the environmental, societal and in- .—— 4 J Freeman, et al , So/ar Power Sate//ite Of f$frore Rectenna stitutional problems associated with land-use Stur/y, contract report No NAS 8-33023, prepared for Marshall and receiver siting might be remedied by siting $pace Flight (-enter, May 1980 receivers in shallow offshore waters. For some ‘ ‘i]tellite Power $y\tem [5PS] Rectenna $Itlrrg A vallablllty and Ll~~trlhurjon of Nor-n jna//y E/jglb/e Sites, DC) E/E R-10041-TI O, No- land-scarce areas such as New England and vem ber 1980 Europe, this concept is particularly desirable. ‘ Crey, [Jp c It

Table 35.—SPS Systems Land Use

Number of Total land area sites for (kmz) SPS system km2/site km2/1,000MW 300,000 MW for 300,000 MW m 2/MW-yra Reference ...... 174.0 35.0 60 10,400.0 1,280 Solid statec ...... 50.0 33.0 180 9,000.0 1,230 Laser Id...... 0.6 1.2 600 360.0 44-35 e Laser Ilf ...... 40.0 80.0 600 24,000.0 2,960-3,550 e Mirror If ...... 1,000.0 7.4 - ’29 2,200.0 274-329 e For comparison Washington...... 174.0 New York City...... 950.0 Chicago...... 518.0 a These “nlt~ are presented for ~O~ParlSOn with table 36, The values for the reference and solid-state designs assuf’rle a so-year lif@tirne and a capacity factor Of ().9. b Rectenna at 34o latitude covers a $jkrn x lskrll (1 ITkrnt) elliptical area, Microwave power density of edge of rectenna is 1.0 mW/cm2. If an exclusion boundary iS Set at 0.1 mW/cm2, then the total land per site is approximately 174 kmz (2 km extra on each side for buffer zone). J. B. Blackburn, Sate//ire Power System (SPS) Mapping of Exc/usion Areas for Rectenrra Sites, DOE/NASA report No. HCP/R-4024-10, October 1978, Does not include land for mining or fuel transport. C The solid-state sandwich design is described in J Grey, safe//j~e power sys~em ~ecffr’rjca/ op~lo~s and Economics, contractor report prepared fOr OTA, NCrV, 14, 1979. d Laser 1 and Laser 11 are two laser systems considered by DOE, Both deliver the same amount of power but the beam of Laser I iS more narrow (and hence more intenSe) than that of Laser Il. See C. Bain, Potentia/ of Laser for SPS Power Transmission, SPS CDEP, October 1978. e The values for the laser and mirror systems assume a 30-year lifetime and Capacity faCtOrs of 0.75-09 f Minor system parameters are defined by SOLARES System as described in K. Blllman, W P Gllbreath, S. W. Bowen, “Solar Energy Revisited With Orbiting Reflectors,” NASA, Ames, g The SO LARES system is designed to deliver 810 GVV to 6 sites; 2 SOLARES sites actually ~)rovlde 270 GW, Ch. 8—Environment and Health ● 199

Table 36.—Summary of Land Requirements

Purpose Construction Plant — Fuel Disposal Transmission CG/CC Quantity —a 7.2-150 m21MW-yr 1,800-4,520 5 m21MW-yr 300 m21MW-yr m2/MW-yr (480 km)b Duration —c 30 yr 30 yr —c 30 yr Location —c —c —c —c —c

FBC Quantity —a 5.2-16.8 m2/MW-yr —c 1.4 m2/MW-yr 300 m2/MW-yr (assume same as combined cycle) Duration —c 30 yr —c —c 30 yr Location —c —c —c —c —c

L WR Quantity —a 57-174 m2/MW-yr 31 m2/MW-yr 4m2/MW-yr 225-1000 m 2/MW-yr (480-1600 km)b Duration —c 30-40 yrs 30 yr 1 06 years 30-40 yrs (20 m2/MW-yr “permanent”) Location —c —c —c —c —c

LMFBR Quantity —a 76-133 m2/MW-yr 5 m2/MW-yr —c 200 m2/MW-yr (plant life- (80 km)b time) and .25 m2/MW-yr (permanent) Duration —c 30 yr —c —c 30 yr Location —c —c —c —c —c .— TPV Quantity —a 600-3,800 m2/MW-yr neg 1d neg 1d 300-3,000 (depending on cell m2/MW-yr efficiency and (480-4,800 km)b capacity factor) e e Duration —c 30 yr NA NA 30 yr Location —c Southwest NA NA —c

STE Quantity —a 2,260-6,650 m2/MW-yr neg1d neg1d 300-3,000 m2/MW-yr 480-4,800 km)b Duration —c 30 yr NA NA 30 yr Location —c Southwest NA NA —c

OTEC d 2 Quantity —a neg1 neg1 neg1 d 300 m /MW-yr (480 km)b e e Duration —c NA NA N A e 30 yr e Location —c NA NA NA —c

SPS Quantity 20-850 km2 1,480 m21MW-yr g neg1d neg1d 300-1,000 (launch) (rectenna) f m2/MW-yr (480-1,600 km)b e e Duration 30 yr 30 yr NA NA 30 yr Location Florida? —c NA NA —c

approximately the Sum of plant and transmission requirements. ‘N A-Not applicable

bDistance to load center. flncludes buffer zone, rectenna proper OcCIJpleS about 50°1. Of total. cData lacking; some categories are discussed I n test 9Assuflles 200 krnz per rectenna site. ‘Negligible. SOURCE: D. E. Newsom and T. D. Wolsko, Prelirnmary Cornparatwe Assessment of Land Use ~Or Satelhte Power Systems and Altemafive E/ecmc Energy Technologies, DOE/NASA report No. DOE/ER-0058, April 1980.

200 ● Solar Power Satellites

Figure 36.—Offshore Summary Map

Offshore siting study - dark areas are not eligible for rectenna siting

SOURCE: Satellite Power System of 1OO41-TIO, November 1980.

If SPS is to be deployed on a multinational Atomic Energy Commission lands, and unac- scale, the siting constraints may be different ceptable topography. Sites were also excluded from those in the United States. This is espe- if they were found within a specified distance cialIy true with respect to microwave exposure from military installations, nuclear power- standards, which in some countries are more plants and other facilities that might suffer stringent than in the United States (see Health from electromagnetic interference with the and Ecology, Microwaves). The environmental SPS microwave field. standards of other nations and their effects on In figure 37, ineligible grids were marked SPS siting requirements need to be explored in with an “x.” In this first exercise 40 percent of more detail. the United States remained eligible. After the A siting study for the continental United application of additional “potential” exclu- States has been conducted for the reference sion variables that were categorized as having system to determine if 60 candidate sites can an unknown or adverse, but potentially cor- be found. ” The United States was divided into rectable impact (e. g., agricultural lands and grids, each approximately the size of a rec- flyways of migratory waterfowl), 17 percent of tenna. Grid squares were eliminated from con- the United States remained eligible. In general, sideration if they violated a set of “absolute” the greatest number of eligible sites was found exclusion variables that included inland wa- in the West, Southwest, and in the northern ters, high population density areas, marsh- regions of the Midwest; the least number of eli- lands, military reservations, habitats of endan- gible sites occurred in the Mid-Atlantic States, gered species, National recreation areas, where 3 to 10 percent of the land was eligible (31 to 83 grids, depending on the criteria for B. and B A “Satellite Power System eligibility). The exclusion variables that had Siting Study, ” in Proceedings of the Power Program Review, Apr 22-25, 1980, DOE/NASA the greatest incremental effect in rendering report No Conf -800491, July 1980 land ineligible included topography, popula-

Ch. 8—Environment and Health • 201

Figure 37.—Satellite Power System—Societal Assessment

SOURCE: Satellite Power Svstem (SPS) and of Nominally Eligible Sites, DOE/ER- 1OO41-TIO, November 1980. tion and electromagnetic compatibility’ (abso- squares. By imposing the constraint that eligi- lute variables) as well as private agricultural ble sites had to fall within a 3 x 3 grid pattern, lands, flyways, and Federal dedicated and pro- the amount of eligible sites dropped dramati- tected lands (potential variables). cally, especialIy in the Mid-Atlantic region and the Southeast. A less restrictive requirements The siting study also revealed an important of 2 x 2 grid patterns produces a considerably point about the siting of smaller rectennas. less drastic result. Smaller site sizes could increase the likelihood that sites identified as eligible (in the first The siting results (from the application of application of absolute exclusion variables) “absolute variables”) were then correlated would remain so upon closer examination in a with the distribution of projected electrical “validation” process. However, they would be demand.46 Based on one projection of future unlikely to make previously excluded grid electricity demand, it was concluded that the squares eligible. Therefore, it was concluded only potential site scarcity would occur in the that smaller rectenna size (i. e., one-fourth or Mid-Atlantic region (see fig. 38). In most other one-half the rectenna area) would not make a regions there wouId be about 100 times more substantial difference in the siting process. 45 eligible grids than “required” sites. Scarcity of large load centers relative to allocated recten- The effects of eliminating isolated sites were nas could be a problem in sections of the Mid- also considered on the assumption that local west and West. variations and the problems associated with public or private land acquisition would make A prototype environmental assessment was siting more difficult in areas that did not con- conducted for a rectenna site in the California tain a large number of adjacent eligible grid desert (Rose Valley, 250-km north of Los

“A “Relationship of Eligible Areas to Projected *This was also an important constraint for the siting of off- Demand, “ in The Final Proceedings of the Solar Power shore Program Review, Apr 22-25, 1980, DOE/NASA report No “Ibid -800491”, July 1980

83-316 0 - 81 - 14

202 ● Solar Power Satellites

Figure 38.—RegionaI Generation (2000) and Rectenna Allocations

18.40/o

600

Note: This is based on the EIA Leap Series C (1978) protection of electricity the year 2000 which assumes a 4 10/. growth rate per year from 1977-1995. See chapter VI or discussion on alternative electricity growth rates SOURCE. A. of Areas to Projected Elect Demand,” Proceed/rigs Power Satellite Program Apr 22-25, 1980, DOE/NASA No conf -800491, July 1980

Angeles).” The major environmental impacts much larger than the minimum requirements (excluding microwave effects) and possible be located in the site selection process. In ad- solutions are summarized in table 37. dition, the study recommends that: 1) rectenna panels be light and open to allow passage of The assessment emphasized that large sunlight and rain; 2) natural characteristics of amounts of contiguous land area must be com- the site be considered in the panel and diode/ pletely committed to the project, totally dipole design, e.g., taking account of possible displacing existing land use and completely attraction birds and rodents might have to the altering the existing natural environment. in- panels for resting or nesting; and 3) the design vestigators also noted that after the site minimize the use of materials. boundaries are selected, there is no flexibility in the siting of individual rectenna structures, Finally, investigators note that the siting of so that areas particularly sensitive to SPS im- receivers in the Southwestern United States pacts could not be avoided. To alleviate ad- will be especially hampered by land-use converse effects, they recommend that land areas flicts with other energy sources, archaeological sites and military programs. In particular it is ype Environmental Assessment of the Impacts of Siting pointed out that 15 percent of the California and Constructing a Satellite Power System Ground Receiv- ing Station DOE/NASA report No DOE/E R-O072, August Conservation Area is reserved for defense pur- 1980 poses. Ch. 8—Environment and Health Ž 203

Table 37.—Summary of Environmental Impacts of Rectenna Construction and Operation at a Specific Study Site

Technical area Rectenna construction Rectenna operation Mitigation

Air quality and climatology . Probable standards . No significant air quality ● Adequate dust suppression violation for nitrogen impacts. program during construction oxides, particulate, ● Unknown, but possibly would mitigate particulate and hydrocarbons. significant microclimateic impacts. ● No climatic impacts. effects at or near ground . Extending construction surface schedule would reduce emission peaks for hydrocarbons and nitrogen oxides. ● Pending further research, project modifications might be needed for ground surface microclimate impact

● Noise ● Substantially elevated . No significant impact. Improved noise control noise levels, but in technology by construction areas with low popula- time frame for vehicles, tion density, equipment, and processes ● Possible impacts on would mitigate impacts. noise-sensitive ● During construction, noise- species. sensitive habitats should be avoided to maximum extent possible during breeding and nesting seasons.

Geology and soils ● Geologic impacts less ● Seismicity has potential . Thorough seismic and soils important than for facility destruction studies required as part of geologic constraints. or loss of efficiency site-specific engineering. ● Study area very active (alinement v. satellite). ● Careful soiI-stabilization/ ● seismically, but within ● Soil productivity impacted age/erosion-control normal range for for project life: depends programs required. southern California. on extent and degree of ● Soils impacts signifi- construction—phase and cant: large disturbed ongoing operations dis- area, compaction, turbance. wind/water erosion. ● Soils constraints: diversity of soils types implies variability in engineering properties (e.g., shrink/swell potential, corrosivity to metals/concrete).

Hydrology and water quality ● Project requirements: . Project requirements minor ● Careful soil stabilization/ 2-14 x 106 m 3 unless major revegetation drainage/erosion- (depends on dust program undertaken. control program required. suppression methods Revegetation could require ● Ground water withdrawal used). 27 x 106 m 3/yr impacts could be ● Meeting project needs for 3 yr, that could alleviated by importing from groundwater cause water table water from outside would lower water drawdown. study area. table 0.2-1.5 m/yr; ● Proper sewage control would reduce under- program necessary during flow to adjoining construct ion to prevent valley, could lower water quality degradation). water level in nearby lake; might con- taminate usable water through hydraulic connection with unusable ground water. 204 ● Solar Power Satellites

Table 37.—Summary of Environmental Impacts of Rectenna Construction and Operation at a Specific Study Site-Continued

Technical area Rectenna construction Rectenna operation Mitigation

Flora ● Land disturbance ● Impacts similar to ● Reestablishment of would completely construction phase. preexisting fIora modify site’s ● Microclimate changes at problematic; major floral communities. ground surface a key and difficult revegetation ● Possible indirect issue for severity program required. impacts on flora from and potential for ● Careful placement of hydrologic changes, mitigation of floral ancillary facilities necessary air and water impacts. to minimize impacts pollutants, and on sensitive habitats. personnel activities ● Careful planning, ● No endangered design and construction/ species present operations practices at Rose Valley/ necessary to minimize Coso; one rare indirect impacts (e.g., species present. water quality degradation). Fauna ● Land disturbance ● Impacts similar to ● Reestablishment of would completely construction phase. preexisting fauna modify site faunal ● Impacts closely problematic; closely communities. related to fIora linked to strategy ● Possible indirect impacts. and success of impacts on fauna ● Microclimate changes floral mitigation. from hydrologic at ground surface ● Careful placement of changes, air and a key issue for ancillary facilities pollutants, personnel severity and potential needed to minimize activities, and loss for mitigation of impacts on sensitive of feeding areas fauna impacts. habitats. for nearby fauna. ● Careful planning, Surface water design, construction, sources for O&M practices, and migratory water construction scheduling and land birds needed to avoid would be lost indirect impacts (Playas) and and to avoid jeopardized (Little sensitive habitats Lake). during breeding and ● One protected species nesting seasons. (Mohave ground squirrel) found in Rose Valley. Land use ● Total displacement Same as construction ● Major impacts could of existing site phase not be mitigated. uses (e. g., It might be possible farming grazing, to achieve joint recreation). use of rectenna ● Minor loss of sites but this mineral resources remains speculative. (cinder, pumice). ● Minor indirect (growth-related impacts. ● Potential land acquisitior/use conflicts with Navy (China Lake NWC), energy (geothermal), wilderness, archaeological resources, native American use and access to cultural and religious sites. SOURCE: Prototype Environmental Assessment of the Impacts of Siting and Constructing a Satellite Power System (SPS) Ground Receiving Station (GRS), DOEINASA report No. DOE/ER-0072, August 1980. Ch. 8—Environment and Health ● 205

Receiver Structure: Weather Modification cant than those associated with nuclear plants of comparable power. 50 Other DOE studies have investigated the potential of the rectenna for modifying local Resources weather. They indicate that the surface roughness and albedo of the rectenna structure and The construction and operation of SPS the waste heat generated by rectenna opera- couId strain supplies of some critical materi- tion (750 MW per site) would have a small, but als, as shown in table 38. The most serious detectable impact on regional weather and cli- problems arise for the solar cell materials (e. g., mate. 48 49 In particular, rectennas would per- gallium, gallium arsenide, sapphire, and solar turb the average surface heat exchange by grade silicon) and the graphite fiber used for about 10 percent. SPS land-use changes could the satellite structure and space construction alter temperature (on the order of 10 C), cloud facilities of the reference system. 51 It appears density and rainfall. However, it is important that the silicon SPS systems pose less serious to note that these effects would be no greater problems than the gallium arsenide option, but than those attributable to other nonindustrial this may be due to the immature state of gal- urban activities. For example, the waste heat lium arsenide technology. The most serious re- generated by typical coal and nuclear plants source strain for the galIium arsenide system is range from 750 to 6,000 MW. The waste heat gallium; for the silicon option, large amounts rejected at laser receptor sites, would also proof electricity might be needed to produce the duce weather effects that would be less signifi- cells.

48 Environrnerrta/ Assessment for the Sate//ite Power System Concept Development and Evaluation Program, op cit. “Proceedings of the Workshop on Meteorological Effects of Sat- ‘OBasu, Johnson, Klobuchar, and Rush, op clt ellite Power System Rectenna Operation and Related Microwave “ R R Teeter and W M jamieson, Preliminary Materia/s Transmission Prob/ems, Aug 23-25, 1978, DOE/NASA report No Assessment for the Sate//ite Power System (SPS), DOE/NASA Conf -7808114, December 1979 report No DOE/E R-0038, January 1980

Table 38.—Summary of Materials Assessment Results

World Percent Percent production SPS Net world supplied as growth percent of percent resource cost Parameter byproduct rate demand imported consumption $Ikw a Threshold value ...... 50% 10% 100/0 50% 200% $50/kw Gallium...... A A A — — — Graphite fiber...... — A A — — A Sapphire...... — A A — — A Silicon SEG ...... – A A — — A Gallium arsenide...... — A A — — A Electricity...... — — — — A — Arsenic/arsenic trioxide...... B — — B — — Kapton ...... — B B — — — Oxygen (Iiq) ...... – B B — — — Silica fiber ...... — B B — — — Silver...... B — — B — — Silver ore ...... — — — B B — Glass, borosilicate ...... — — B — — — Hydrogen (Iiq) ...... — B — — — — Mercury ...... — — — B — — Mercury ore ...... — — — B — — Methane...... — B — — — — Petroleum...... — — — — — B Steel ...... — — — — — B Tungsten ...... — — — B — —

Note: “A” signifies problem of serious concern “B” signifies problem of possible concern. aparameter Value above Which a potential problem exists. Materials in this table exceeded these values where an “A” or “B” is recorded. SOURCE: R. R. Teeter and W. M. Jamieson, Prelimlrrary Materials Assessment for ttre Satellite Power System (SPS), DOEINASA report No. DOE/ER-0038, January 1980. 206 ● Solar Power Satellites

Most of the resource constraints identified Mining, Manufacturing, and Transportation stem from limitations in production capacity The minerals extraction, materials process- rather than exhaustion of reserves. SPS could ing, manufacturing, and transport activities compete for graphite composite with the auto- associated with SPS could result in a meas- mobile industry and, depending on its time of urable increase in air and water pollution and introduction, with terrestrial photovoltaic sol id wastes. 52 For example, the potential envi- technologies and the electronics industry for ronmental impacts of mining include water semiconductor materials. The demand by SPS pollution from leaching and drainage mod- for a few materials such as gallium, tungsten, ifications, air pollution from fugitive dust and and mercury could also increase U.S. depend- land disturbance from strip mining, subsidence ence on foreign sources. Further analysis and spoil piles. Manufacturing would produce wouId be required to determine the severity of stack emissions, process effluents and solid the resource limitations identified for the wastes. In table 39, order-of-magnitude esti- reference system and possible measures that mates have been made of some of the environ- wouId circumvent them. mental impacts resulting from these reference While no assessment has been made of the system activities. The incremental domestic material requirements for any of the other SPS processing of materials required for SPS can technical options, a few observations can be also serve as a rough guide to increased pollu- made. The solar celI, graphite, and transportation levels. tion materials that are problematic for the While these exercises help identify the reference design might also be used in the potential scope and extent of environmental three other options. The solid-state design calls impacts, a thorough and quantitative assess- for silicon or gallium arsenide devices in the ment is presently lacking. However, it is transmitting antenna as well as in the solar col- anticipated that most impacts would be con- lector. While the solid-state satellites would be ventional in nature and could probably be smaller than the reference design, the solid- minimized by methods currently used in indus- state material needs per unit energy would be try 5‘ There is no information on similar effects greater. Therefore, if the reference design were to strain supplies of semiconductor materials, ‘ /’rfj[o/ I I)(I I nvlronrrrent,]/ A >je~smerrt ot the /rrrpactj ot fi(lng ,2 n(l ( on\ [ rj 1 f t /nLJ ,] S

due to the other SPS technical systems. Studies needed to determine the incremental effect of should be conducted as the design parameters SPS on the environment relative to other elec- become more clear. Analysis would also be tricity generating faciIities.

HEALTH AND ECOLOGY

Human health and safety could be affected workers will be discussed. With the exception by launch and space activities, mining, manu- of power-transmission effects, most of the facturing, and transport, and the construction health and safety risks described here pertain and operation of SPS receiving antennas and to the reference system only. There is not powerlines. These effects and the public enough information on the personnel require- concern about them are likely to be most ments, industrial activities and environmental pronounced closest to launch and receiver fa- impacts to treat adequately the other tech- cilities. Long-term exposure to low-level elec- nical options. It is assumed that many of the tromagnetic radiation from SPS power trans- effects would be similar to those of the ref- mission and distribution is a critical issue, erence system, varying only in intensity and involving potential health effects about which degree. It is important to note that some of the very Iittle is known. For SPS space workers, ex- impacts identified for the reference system posure to ionizing radiation is of the utmost could be minimized or avoided by worker concern. Other important terrestrial impacts training, protection devices, or changes in the are shown in table 40. While the effects of system design, but the effect of these measures some SPS activities such as mining and man- on concept feasibility and cost need to be ufacturing are fairly conventional and could examined in more detail. be routinely assessed, the uncertainties of other health and ecological impacts, such as exposure to microwaves, are great. When ex- Terrestrial Effects perimental data does exist it is rarely directly applicable to SPS. Furthermore, extrapolation The primary sources of potential health and from experimental animal to human health ecological effects are electromagnetic radia- and safety standards is tenuous and uncertain tion from the power transmission and distribu- without a good theory on which to base the ex- tion systems and noise and pollution from trapolation. For other impacts, such as ex- launches, mining, manufacturing, and con- posure to ionizing radiation, it is not clear if struction (see table 40). The risks to the ter- existing standards should apply to SPS. More restrial worker are usually greater than to the stringent standards can strongly influence SPS general public because of the increased fre- design, cost, and social acceptability. Ecologi- quency, duration, and intensity of occupa- cal effects of SPS are also extremely uncertain tional exposure to certain hazards (although as little attention has been paid to this com- occupational exposure could be more easily plex area. controlled by protective devices). Estimates of SPS hazards have in many cases been extrapo- This second part of the chapter will identify lated from other technologies, such as the the health and ecosystem impacts that pres- space shuttle. Risk analysis would improve as ently appear most significant. The first section the system design becomes more clear. How- will address the bioeffects of terrestrial ac- ever, the major uncertainties associated with tivities on the public, SPS workers and eco- some effects (e. g., electromagnetic radiation) systems. In the second section, the implica- rest in the state of biophysical knowledge and tions for the health and safety of SPS space not SPS specifications. 208 ● Solar Power Satellites

Table 40.—Terrestrial Health and Ecological Impacts Electromagnetic Radiation

Microwaves Over the last few decades, the development ● Effects of public and ecosystem exposure to low levels and proliferation of technologies that utilize uncertain electromagnetic radiation has been astound- ● Occupational exposure higher; may require protective clothing ingly rapid and widespread. However, there is Laser Light a growing concern about the biological conse- • Hazard to people and other living organisms directly ex- quences of exposure to the radiant energy posed to beam these devices employ. Terrestrial life as we ● Hazard to slow airplanes, birds, and insects flying through the beams know it has evolved in response to a very Reflected light (mirror system) specific spectral distribution, diurnal and ● Ocular effects not expected to be significant; potential seasonal cycle, and intensity of solar and ter- hazard with binoculars not known . Psychological impacts on public, effects on the restrial radiation. It is possible that the alter- photoperiod of plants and circadian rhythms, and naviga- ation and enhancement of the ambient election of wildlife are unknown tromagnetic environment brought about by Reflected light (from reference system) modern technologies could have a profound ● Plants and animals would probably not be unduely affected, but many effects are uncertain. The human eye impact on biological entities and human could be damaged if SPS reflected light were viewed for health. too long or with magnifying devices. High-voltage transmission lines SPS would increase the local levels of non- ● Effects of public and ecosystem exposure to elec- ionizing radiation (see fig. 39) in a few areas of tromagnetic fields not well demonstrated but still uncer- the spectrum, e.g., microwaves, infrared laser tain (not unique to SPS) light, or reflected sunlight from the power- Noise ● Without preventative measures, construction noise from transmission system .54 The distribution of certain machinery could exceed occupational standards; power from the receiving site via transmission no significant public or ecosystem effect is anticipated lines would also increase exposure to very low ● Launch noise and sonic booms couId present problems for public and ecosystems. Workers would wear heavy frequency or static field radiation at some protective devices locations. Light reflected from the surfaces of Air Pollution space structures and vehicles would be visible • Without preventative measures, construction of recten- from Earth. Space workers involved in the con- nas couId violate standards for certain emissions such as hydrocarbons and particulate struction and operation of SPS could also be ● Mining, manufacturing, and transport emissions are ex- exposed to high levels of nonionizing and pected to be comparable to industrial and energy produc- ionizing radiation in space. ing processes (except coal) ● Launch effluents are not thought to exceed emissions standards unless ambient levels are high but studies MICROWAVES must be refined There is not enough relevant data currently Ž Effects on ecosystems are unclear available to assess reliably the biological risks Water Pollution ● Construction and revegetation could deplete or con- to humans, plants, and animals exposed to SPS taminate local water, depending on site microwaves. The data base that does exist is in- ● Onsite facilities would be needed to treat polluted water complete, often contradictory and usually not at launch site directly applicable to SPS.55 In particular, Safety • Risks to public, workers, and ecosystems from the handling and transport of toxic and explosive materials such as rocket propellants 54P Lorraln and D R Corson, E/ectrornagnetic Fie/ds and • Occupational risk of catastrophic explosion or launch ac- Waves (San Francisco W.H Freeman, 1970) 5 sprel;m ,nar y fn v;ronmenta/ Assessment for the Sate//ite power cident higher than that for public and ecosystems System [SPS) Revision 1, DOE/NASA report No DOE/E R-0036, SOURCE: Office of Technology Assessment. January 1980

Ch. 8—Environment and Health ● 209

Figure 39.—The Electromagnetic-Photon Spectrum

Bolometer Sparks Lamps

Thermopile Hot bodies Magnetron Klystron

Travelling-wave Crystal tube

Electronic Electronic circuits circuits

AC generators 210 ● Solar Power Satellites

there is a lack of information on the bioeffects wave beam if other protective measures prove of chronic exposure to microwaves at low- insufficient. Additional research would be repower densities. Data is presently lacking on quired to clarify the risks and protective empirical dose-response relationships at these criteria for short-term exposure. Possible syn- low levels as well as on the theoretical mech- ergisms between the space environment (e. g., anisms of interaction between Iiving organisms ionizing radiation, weightlessness) and micro- and microwaves. Improved theory would facil- waves must be explored as well as the plausi- itate extrapolations (which are currently ten- bility of simultaneously shielding microwaves uous and oversimplified) from experimental and ionizing radiation (see Space Environ- animal data to the prediction of human bio- ment). It is also imperative that understanding effects. of the long-term effects improve substantially (see below) before a reliable occupational This knowledge is also required for the quan- safety threshold can be determined. In addi- tification of SPS microwave risks, without tion, possible disparities between SPS micro- which no useful assessment of the SPS microwave levels and occupational standards in this wave concepts can be made, If an SPS pro- and other countries (see table 42) should be ad- gram is pursued, the study of microwave bioef- dressed, especially if SPS were to be a multi- fects should receive top priority. Microwave national system. The effects on system cost research and future microwave standards and feasibility of implementing protective could play a large role in determining the measures, complying with safety standards, design and feasibility of SPS systems. and reducing the risks of long-term effects will ● SPS microwave risks. The SPS reference sys- need to be analyzed. tem microwave environment is illustrated ’in Public and ecosystem exposure to SPS mi- figure 40. Table 41 presents the public, occu- crowaves is presently of greatest concern. It pational, and ecosystem exposure levels. has been estimated that the 60 satellite refer- Since the power densities emitted by the ence system would raise the ambient micro- solid-state system are lower as a function of wave level in the continental United States to distance from the rectenna center than the a minimum of 10-4 mW/cm2. 57Although not reference system, they will not be specifi- directly comparable, this level is two orders of calIy addressed here. magnitude greater than the median population No quantitative risk assessment for SPS exposure to FM radiowaves.58 (Ambient micro- workers has been performed or is currently wave and radio frequency levels are inturn 106 possible. Occupational exposures would need times greater than natural levels of solar and to be controlled by adequate protective cloth- terrestrial radiation.) It therefore appears that ing and shielding, dosimeters (all of which are the general population and ecosystems would not presently available), and possibly changes be exposed to levels significantly higher than in system design.56 The extent of the necessary current background microwave radiation. protection has yet to be determined. For oc- The health risks of chronic exposure to cupational exposure engendering the greatest microwaves, especially at these low levels (i. e., risks, (e. g., space workers and terrestrial personnel working above the rectenna) it might be necessary to shut off or defocus the micro- . “lbld “R A Tell and E D Mantiply, “Population Exposure to VHF and U H F Broadcast Radiation in the United States, ” Proc. IEEE, 56prOgram A Ssessment Report, Statement of F;nd;ws, oP c It 68(1 ) 6-12, 1980 Ch. 8—Environment and Health . 211

Figure 40.—SPS Microwave Power-Density Characteristics at a Rectenna Site

I Power denisity is rectenna center

0.02 mW/cm2

10 km 13 km at 35@ 0.1 mW/cm2 at rectenna site exclusion boundary

SOURCE: Enwrorrnrenta/ Assessment for the Sate///te Power System Concept Development and Eva/uat/on Program, DOE/ER-0069, August 1980

Table 41 .—Characterization of Exposure to Reference System Microwaves — 4 2 2 Outside buffer zone —— Between 10- mW/cm and 0.1 mw/cm Public Airplane flying through beam Less than 23 mW/cm2 (shielding) Terrestrial workers Rectenna field Up to 23 mW/cm2 (may be higher if reflections occur) Space workers Transmitting antenna Up to 2.2 W/cm2 Rectenna field: Ecosystems (plants, Under Outside buffer Less than 0.1 mW/cm2 wildlife, airborne rectenna biota) Inside buffer Between 0.1 mW/cm2 and 1.0 mW/cm2

Rectenna field: above Up to 23 mW/cm2 rectenna SOURCE: Environment/ Assessment for the Sate//ite Power System Concept Development and Eva/uat/on Program, DOE/ER-0069, August 1980. 212 ● Solar Power Satellites

Table 42.—Microwave Exposure Limits

Frequency (G Hz) Occupational (mW/cm2) Occupational duration Public (mW/cm2) United Statesa ...... 0.01-100 10.0 No limit None U. S.S.R.b ...... 0.3-300 0.01 Workshift 0.001 Canada C...... 1-300 5.0 8 hours 1.0 Czechoslovakia ...... 0.3-300 0.01 8 hours 0.0001 Poland...... 0.3-300 0.2 10 hours 0.01 Sweden d ...... 0.3-300 1.0 8 hours 1.0

aThi~ is a ~uid~li”~ ~nlY and is “Ot ~nf~~C.abl~; the ~tarldard~ i“ the united Kingdom, German Federal Republic, Netherlands and France are similar to that Of the U.S. guideline; ANSI will probably recommend 5 mWlcm2 as a new occupational exposure limit. ANSI and EPA are presently considering a new population limit. bo,l mwlcmz for rotating antennas. ccanada is proposing a 1 ITrw/cITIz limit at 10 tdHz to 1 GHz ‘requency. d5 mwlcm~ at o.01 to 0.3 GHz for 8 hours. SOURCE: Adapted from L. David, A Study of Federal Microwave Standards, DOEINASA report No. DOEIER-1OO41-O2, August 1980.

less than 1.0 mW/cm2) cannot be analyzed with through the beam. Birds in flight are often near the current data base. While appreciation for their thermal Iimit and exposure to micro- the complexities of the interaction between waves might result in thermal overloading. ” microwaves and biological systems (see app. DOE has initiated three laboratory studies to D) has grown in recent years, the state of test the effects on bees, birds, and small knowledge, particularly with respect to low- animals at SPS frequency and power densities. power microwaves, is immature and incom- (See app. D.) While no significant effects have plete; hence, no assessment for SPS can be been observed to date, the research is far from conducted at this time. However, a DOE re- completed. view of the existing scientific literature iden- ● Research needs. A workshop organized by tified the biological systems that might be the National Research Council (NRC) recent- most susceptible to microwaves. 59 For the pub- ly identified the principal research priorities lic and ecosystems outside of the rectenna, for the bioeffects of exposure to low-level DOE tentatively concluded that effects on the SPS microwaves.63 These are listed in table reproductive systems would be small; risks to 43. Basically, three kinds of laboratory special populations (e. g., people taking medi- studies are needed: cation, children, older and pregnant people, etc. ) and effects on behavior would be uncer- 1 animal laboratory experiments to estab- tain and effects on the immune and blood lish effects empirically as well as dose- systems appear unlikely. No cancer, devel- response relationships; opment or growth effects would be expected. 2 studies of mechanisms of interaction at Again, however, the data base on low level different levels of biological organization chronic exposure that supports these conclu- (e.g., atoms, molecules, cells, organs); and sions is incomplete and more research would 3. improvement of dosimetry, instrumenta- be required to satisfactorily assess potential tion and models. effects. While limited resources might dictate that For ecosystems (and SPS workers) at the these studies be carried out only at the SPS rectenna site, effects on physiology, behavior, reference system frequency and power densi- development, reproduction and the thermo- ties, it is clear that research at many fre- regulatory, immune and blood systems might quencies and power densities would help to be possible.60 Of particular concern are the elucidate the fundamental mechanisms of effects on insects and birds that might fly interaction that allow extrapolations to be made between frequencies, irradiance and 59A. R. Valentine, “Environmental Assessment Overview,” In The Final Proceedings of the Solar Power Satellite Program Re- blEnvlronmental Assessment for the Satellite Power System view, Apr 22-25, 1980, DOE/NASA report No Conf -800491, July Concept l)evelopment and Evaluation Program, op cit 1980. ‘Zlbld ‘“I bid “Dodge, op cit Ch. 8—Environment and Health • 213

Table 43.—Research Needs To Help Reduce Uncertainties Concerning Public Health Effects Associated With Exposure to SPS Microwave Power Densities and Frequency — Local or general thermal effects Effects on calcium ion efflum in brain tissue 2 ● Long-term experiments at power densities< 0.1 mW/cm ● Studies to determine bioeffects using 2450 MHz as the at whole body, organ, and organelle levels, testing for bio- carrier frequency or studies to determine whether the logical endpoints such as alteration of enzyme reaction power density “windows” are carrier-frequency depend- rates and cell membrane confirmational changes. ent. ● Studies of basic physical interactions of electromagnetic ● Studies to establish the interaction mechanism (the in- fields with molecular components of living tissue, to de- teraction site) of the modulated fields and ELF fields on velop models of biological effects or phenomena. (For ex- calcium ion efflux. ample, biophysical experiments are required to deter- ● Studies to determine whether the phenomenon will occur mine the role of microwaves at SPS frequencies and in- under the modulation and power characteristics ex- tensities at the molecular level and their action on ionic pected of the SPS microwave beam. conductivity. Any responses, biological, biochemical, or ● Studies to determine whether the calcium ion efflux physical, should be investigated from the point of view of phenomenon correlates with Russian and East European alteration of enzyme reaction rates, and cell membrane findings of neurological/behavioral decrements in people phase transitions and confirmational changes.) and animals exposed to low levels of microwaves. ● Better dosimetry techniques for calculating and measur- ● Experiments to determine whether other ions—sodium, ing (such as a probe that could be used within an potassium, magnesium–are similarly affected. organism to measure in a nonperturbing way) internal Effects on organized structures field patterns. ● Studies of changes in behavioral responses under Interactions with drugs or other chemicals simulated SPS conditions, using behavioral tests (such ● Repeat selected experiments showing effects (including as time-based schedules of reinforcement) that are both the potential of microwaves as a cocarcinogen), using sensitive and reliable measures of such effects. carefully controlled dosimetry and statistical analysis. ● Studies of long-term effects. ● Develop and test hypotheses to explain effects. ● Neurological and blood-brain barrier experiments at low ● Long-term dose-response experiments at power den- levels. 2 sities around 0.1 mW/cm and with a larger number of ● Determine the neurological and physiological drugs at whole body, organ, and organelle levels. significance of behavioral responses. Immunological effects ● Molecular level studies on biological relaxation times. ● ● Repeat selected Russian research at 1 to 500 mW/cm2 Consideration of long-term animal experiments at 2,450 levels; repeat selected U.S. work to validate it. MHz to evaluate, if possible, whether there is any trend ● Mechanistic and molecular biological experimentation. toward life shortening in animals. ● Long-term studies, particularly autoimmune response. ——.. SOURCE: C H. Dodge, (rapporteur), Workshop on Mechanisms Under/y/ng Effects of Long-Term Low-Level, 2.450 MHZ Rad/at/on on Peep/e, organized by the National Research Council, Committee on Satelllte Power Systems, Environmental Studies Board. National Academy of Sciences, July 15.17, 1980 species. It may also be possible that frequen- limited usefulness for exposure to low levels of cies other than 2.45 GHz would be used for microwaves because the variability of the re- SPS. If a much different frequency were used, sponse is small and might be masked by other however, low-level microwave research would effects. It is also not clear how many people have to be done at that frequency as well, would need to be observed. Nonetheless a because different frequencies cause different coordinated program of prospective epide- responses, miology (as opposed to retrospective studies that rely on medical records many years after In addition to laboratory experiments, epi- exposures) and laboratory research is essential demiological studies are also needed.64 It has to bridging the gap between biological effects been argued that such studies are currently of observed in a laboratory animal and human limited usefulness; they are very expensive, dif- health standards. ficult to accurately document (i.e., it is difficult to determine the dose to which individ- Special attention must also be paid to ef- uals are exposed) and may overlook important fects on ecosystems. To date, nearly all studies biological endpoints.65 In addition they have have been conducted in a controlled labora-

“Office of Science and Technology Policy, A Technica/ /7e- tory environment on a relatively few species. view of the Biological Effects of Non-lonlzlng Radiation, Wash- Virtually nothing is known about the effects of ington, D C , May 15, 1978 65paul Tyler, Armed Forces Radiological Research Institute, microwaves on a complete ecosystem and no private communication, July 30, 1979 studies have been performed that even ap- 214 • Solar Power Satellites

preach the projected time scale of SPS opera- Standards Institute (ANSI) which in 1966 tion (i.e., 30 to 100 years). With respect to SPS, recommended a maximum permissible ex- it must be determined if animals and airborne posure of 10 mW/cm2, averaged over any 6- biota would be attracted to the beam or would minute period (1 O to 100 GHz).70 This ra- avoid it. What impact would microwaves have tionale also forms the basis of the current on the navigational systems of birds and in- U.S. occupational guideline (which in 1975 sects (as well as aquatic life for offshore was ruled advisory rather than a mandatory rectennas)? What effect would exposure to standard”) as promulgated by the Occupa- microwaves have on the productivity of plants tional Safety and Health Administration and their susceptibility to drought? How would (OSHA) which adopted the ANSI recommen- SPS affect the local food chain? The effects on dation in 1971. Presently, there is no official micro-organisms, such as bacteria, fungi, and recommendation for general population ex- algae should be invest igated. 66 posures in this country.

● Microwave standards. The biological con- The reasoning underlying the U.S. guideline sequences of exposure to low-level micro- is currently in dispute and OSHA and ANSI are 72 73 waves are poorly understood because of considering new recommendations. The inadequate and sporadic support of micro- confIict centers around the assumption that wave bioeffects research in general and only thermal effects result from exposure to because the bulk of research performed in microwaves. While it is generally acknowl- this country has focused on the bioeffects at edged that exposure to microwaves of 10 levels of 10 mW/cm2 or greater.67 This em- mW/cm 2 or greater will result in heating, the phasis stemmed from a belief that the only effects and consequences of exposure to lower biologically significant damage from ex- power densities are controversial. Experiments posure to microwaves is due to heating. In documenting behavioral and neural changes fact, occupational guidelines developed in and the enhancement of calcium efflux from 74 the 1950’s through the Department of De- brain cells in particular have suggested the fense and its contractors in response to con- existance of other effects at power densities cerns about exposure of radar personnel below 1.0 mW/cm2. These phenomena are were based on biological injuries (e. g., thought by some to result from direct interac- cataracts, burns) from acute exposure to tions with the electromagnetic field rather microwaves on the order of 100 mW/cm2. It than as an indirect consequence of heating. was concluded that humans could well tol- Some of the mechanisms that have been postu- erate exposures to power densities 10 times lated for non ionizing radiation include: 68 2 smalIer (i. e., 10 mW/cm ) without suffering 1. distortion of the shapes of individual serious or permanent damage. 69 This reason- molecuIes or rearrangement of a group of ing was accepted by the American Standards molecules that might transiently or per- Association (now the American National ——.. ‘“L David, A Study of Federal Microwave Standards, DOEI ““0 P Gandhi, “ Blohazarcf~ ot Microwave Beams From Prc~- NASA report No DO E/E R-10041-02, August 1980 7 posed Satel Ilte f]ower St~tlon~’, I n 1 ~ea /th /rnp/lcatlon$ of New ‘General Accounting Office, Efforts by the Errvironrnenta/ Pro- f nergy Tccfrno/oKlc\, W N Rom and V [ Archer (eds ) (Ann Ar- tection Agency to Protect the Public From Environmental Non- bor, MI( h Ann Arbor Scien{ e Publ l~her~ I n( , 1980) Ion\zrng Radiation Exposures, Washington, D C , Mar 29, 1978 “7P Tyler, “Overview of Radlatlon Rt’sear( h Past, f’resent and ‘ A W (;uy, “Non-l onlzlng Radiation. Doslmetry and lnterac- Future, ” I n B Io/oHIca / / ffec ( $ 0 f Nom Ion IZ Inx Racf Ia t Ion, P Tyler tlon, ” I n Non-Ionizing Radiation, proceedings of a Toplca I Sym- (ecf ) (New York Academy of Science\, annal~, VOI 247, 1975) posium, Nov 26-28, 1979, The American Conference of Govern- ““R Bower\, et al , ( ommun~catfon~ for a Mof)I/e $ocrety (Bev- mental I ndustrlal Hyglenlsts, I nc , 1980 erly H I I Is, Ca I If \age PLI bl I cat Ion\, 1978) ( Bel I [ aboratorles and “‘Z R (;laser, “Basis for the NIOSH Radiofrequency and Mi- General F Iectrl[ rec ommencfeci () 1 nlW ( m’ and 1 () rnW/cm’ crowave Rad Iatlon Criterl a Document, ” In Non-Ionizing Radia- re~pect Ively as maxr m um perm I\\ I ble expofure I Im Its ) tion. proceedings of a Topical Symposium, Nov 26-28, 1979, The ““N H Steneck, H j Cook, A j Vancfer, and C 1 Kane, “The American (-onference of Governmental I ndustrlal Hyglen ists, Origln$ of U S Safety Standard\ tor Microwave Kadlatlon, ’ Int , 1980 $c/cnce, VOI 208, pp 1230-1237, j une 1 ], 1980 “Dodge, Op clt Ch. 8—Environment and Health ● 215

manently alter the function and replica- “microwave sickness” has been isolated as a tion process of a biological unit;75 distinct occupational disease in the U. S. S. R.” 2. reorientation of dipole molecules in the It has also been argued that the Soviet ex- microwave field and polarization of mol- posure levels are based on the occurrence of a ecules that control membrane perme- biological effect whereas the U.S. guideline abiIity; 76 reflects levels of known biological damage 3. biological electromagnetic interference in (with a safety margin). ” Moreover, it has been which the microwave field disrupts or en- claimed that the Soviet standard has been set hances the transfer of biological informa- without regard to the practical feasibility of tion in the form of electromagnetic meeting such low levels. It is further argued energy between molecuIes and celIs; 77 that in any case the standards are not en- and forced, especially in the military sector, 4. field receptor interactions where neural although this would be difficult to sub- tissue acts as a receptor of weak fields. 78 stantiate.

The discussion of low-level effects is For many years the flow of information be- hampered by the experimental difficulties of tween East European and Western researchers isolating the various possible mechanisms. was restricted. Translation problems some- Most U.S. microwave experts acknowledge the times also contributed to misunderstandings.83 need for research on low-level effects, but re- This situation has improved considerably, and main skeptical about their biological signifi- attempts are being made in the United States cance, especially at the proposed SPS single to replicate many of the low-level experiments frequency of continuous radiation. performed in other countries (although the United States still has not sponsored any The controversy over low-level effects has clinical studies). Western literature is also been fueled by the disparity between U.S. and beginning to acknowledge the possibility of U.S.S.R. research and exposure standards (see behavioral response and selective sensitivity table 14)—the Soviet standard is three orders of organs to low levels .84 Partly for these of magnitude lower than the U.S. guideline. reasons, it is anticipated that new ANSI guide- Some U.S. authors have attributed the differ- lines will be established that are more stringent ent standards to dissimilar research philoso- 79 than the present exposure levels (see fig. 41). At phies. For example, microwave studies the SPS frequency of 2.45 GHZ, the maximum thought most valid by U.S. scientists are those occupational exposure that is now being con- performed in a controlled laboratory environ- sidered is 5 mW/cm2. * EPA is also considering ment, whereas Soviet researchers rely on clin- — .— 80 ical and “subjective” data as well. In fact, “C H Dodge and Z R Glaser, “Biomedical Aspects of Radio based on the complaints of radar personnel, Frequency and Microwave Radlatlon A Review of Selected Sovi- et, East F u ropean, and Western References” I n Bio/ogica/ Effects “K D Straub, “Molecular Absorption of Non-Ionizing Radia- of E Iectromagnetic Waves: .Se/ected Papers of the USNC/URSl tion in Biological Systems” In The Ph yslca / Basis of Electromag- Annual/ Meeting, L L Johnson and M Shore (eds ), Boulder, netic Interactions With Bio/ogica / Systems: Proceedings of a COIO , October 1975, USDHEW, (report No (FDA) 77-8010/8011), Workshop, University of Maryland, june 15-17, 1977, L Taylor Washington, D C 1976 and A Cheung (eds ), US DHEW, 1978, report No [FDA) 78-8055, “[1 Mlchaelson, In Symposium on the Bio/ogica/ Effects and Washington, D C , April 1978 Health /mp/lcations of Microwave Radiation, S Cleary (ed ), “A S Pressman, E/ectromagnet~c F)e/ds and Life (New York RI( hn~ond, 1969, USDHEW, report No BRH/DBE 70-2, 1970, pp Plenum Press, 1970) 76-81 “lbld “‘F’rzemyslaw Czerskl, Department of Genetics, National Re- “D R Justesen, et al , “Workshop on Radiation: Scientific, sear( h I nstltute of Mother and C h ild (Poland), private commu n i- Technological, and Soclologlcal Implications of Research and catlon Sept 5, 1979 on Biological Effects of Radio-Frequency E Iectromagnetic Radi- “’C H Dodge and Z R Claser, “Trends In Non-ionizing Elec- ations, ” In Proceedings of the 1978 Conference on U.S. Technical tromdgnetlc Radlatlon Bioeffects Research and Related Occu- Po/icy (New York. IEEE, 1979) pational Health Aspects,” Iournal of Microwave Power, VOI 12, “W C Milroy and S M Michelson, “The Microwave Contro- No ~ 1977, Pp 319-334 versy, ” /nternationa/ journa/ of Envlronmenta/ Studies, VOI 4, p *Thl\ level has been criticized by the National Resources 123, 1973 Defense Councrl as being arbitrary and not found with any ‘“D R J ustesen, Veterans’ Admlnlstratlon, private communi- recognition of possible nonthermal effects, see ch, 9, Pub/ic cation, J u Iy 16, 1979 /5 $11(?’> 216 ● Solar Power Satellites

Figure 41 .—Comparison of Exposure Standards Figure 42.— Program Funding

101

,00 1

SOURCE: A. W. Guy, “Nonionizing Radiation: Dosimetry and Interaction,” in Nonionizing I?adiationj Proceedings of a Topical Symposium, Nov. 26-28, 1979, The American Conference of Governmental Industrial Hygienists, Inc., 1980. FY-77 FY-78 $7.6 M $10.1 M the development of exposure guidelines for SOURCE: Fifth Report on “Program for Contro/ of Electromagnetic Po//ution of the Environment: The Assessment of Biological Hazards of Nonion- the general population, although it does not Izmg Electromagnetic Radiation, ” NTIA report No. 79-19, U.S. Depart- have the jurisdictional authority to enforce ment of Commerce, March 1979. standards. It is conceivable that future public standards could be established at 1.0 mW/cm2 elude the Department of Health and Human or below.85 The impact of more stringent Services (the Bureau of Radiological Health/ standards on SPS design and concept viability Food and Drug Administration, for example, should be addressed. sets emission standards for electronic products Agencies. At present, the study of the bioef- such as microwave ovens); the Department of fects of nonionizing radiation falls under the Labor (which sets occupational guidelines); jurisdiction of 13 Federal agencies.86 The allo- and EPA (which sets environment guidelines cation of funds (currently about $15 million for other Federal agencies). per year) is shown in figure 42. The agencies The Federal effort has been coordinated at primarily responsible for regulation and the various times by other Federal agencies, but a establishment of microwave guidelines87 in- clear, dedicated, well managed and ade-

*’David, op. cit. quately funded national program in micro- 8bF;fth Report on “program for Contro/ of Electromagnetic po/- wave bioeffects research is currently lacking. Iution of the Environment: The Assessment of Biological Hazards To some extent, the ineffectiveness of the of Nonionizing Electromagnetic Radiation, ” NT I A report No 79-19, U.S. Department of Commerce, March 1979. agencies responsible for the management of 87 David, op cit the Federal program is due to lack of control Ch. 8—Environment and Health ● 217

over the allocation of research funds .88 It is not contribute significantly to basic under- also often the case that within each of the standing. In addition, long-term continuous research and regulatory agencies, microwave studies are needed and project-specific re- research receives low priority on the agency’s search is sporadic and unpredictable. agenda. jurisdictional ambiguities have Nonetheless, unless the Federal research ef- caused some agencies to take a limited ap- fort is consolidated into fewer agencies and proach to research and protection. Multi- given greater support, it is likely that an SPS agency effort has also made public partici- program would be required to sponsor micro- pation and education difficult. wave bioeffects studies as it did in the DOE Often, the most cohesive and vigorous reassessment. If the current climate continues, search and evaluation of microwave bioeffects this research would not only gather informa- take place in conjunction with one particular tion specifically relevant to SPS, but would technology such as a radar facility. This is not probably be quite fundamental in nature. If a always the best arrangement since in the past, microwave SPS program is pursued, the devel- user agencies with vested interests have often opment of SPS would entail the involvement been responsible for the assessment of health of the Federal agencies shown in table 44. and environmental impacts. Moreover, funda- State agencies might also be affected. mental research is needed in order to elucidate Conclusion. DOE-sponsored microwave the mechanisms of interaction; technoiogy- studies stimulated thinking about the design of specific research is helpful but usually does microwave bioeffects experiments, tended to 68 Tyler, op cit clarify research needs and obstacles and con-

Table 44.—SPS Development

SPS development phase Microwave aspect Agency involvement — —— . . .—. . .. —- . . . . - . Basic research ...... Environmental and public health effects DOE,-- EPA, HEW/FDA, NASA evaluation MPTS technology Applied research ...... Conduct experiments and further define DOE, NASA, HEW/FDA, Department of health and safety risks of MPTS to Labor/OSHA EPA public, the environment and SPS workers Exploratory development ...... Preliminary standards development HEW/FDA, DO E/EV, EPA, HEW/FDA, radiation exposure standards Bureau of Radiological Health, Department occupational health and safety of Labor/OSHA standards development Technology development ...... Final standards for MPTS chosen HEW/FDA, DOE/EV, EPA, DOL/OSHA occupational health and safety standards finalization Engineering development...... Preparation of environmental impact Council on Environmental Quality Demonstration ...... Guidelines for health and safety Department of Labor/OSHA (worker) enforcement Guidelines for public health and safety HEW/FDA-Bureau of Radiological Health, environmental impact statements EPA, Council on Environmental Quality Commercialization...... Review guidelines for worker Department of Labor/OSHA health and safety Review guidelines for public health HEW/FDA, EPA and safety Production ...... Enforcement of guidelines for Department of Labor/OSHA worker health and safety Enforcement of regulations for EPA public health and safety Operations ...... Enforcement of guidelines for worker Department of Labor/OSHA health and safety Enforcement of guidelines for public EPA health and safety

SOURCE: L. David, A Study of Federa/ M/crowave Standards, DOE/NASA report No DOE/ER-10041 .02, August 1980.

83-316 0 - 81 - 15 218 Ž Solar Power Satellites

tributed to an increased study capability. focus the laser beam if a plane did happen to While the results of these studies are useful, fly through it. the time and resource constraints of the SPS The primary risk to the public and nearby assessment program precluded a thorough re- ecosystems outside of the direct beam wouId search agenda; in particular, no studies on be due to laser light scattered from clouds, long-term exposure to low levels of micro- dust and the receptor site. This “spill over” of waves could be initiated and little more could laser power (less than 1 percent) would neces- be done to improve our theoretical under- sitate establishing a buffer zone surrounded by standing. In spite of the general acknowl- an opaque, talI fence.93 As shown in figure 33, edgment by the microwave community of the it has been estimated that a protection radius need for studies of chronic, low-level exposure, of 300 to 800 m wouId be required in order to practically no such studies are underway or limit public exposure at the perimeter to 10 planned. Clearly, if many of the fundamental m W/cm a recommended maximum whole- questions about the bioeffects of microwaves body irradiance limit.94 More research would are to be resolved within the next one or two be needed to verify this exposure guideline decades, a more comprehensive, dedicated na- and to investigate the effects of chronic ex- tional research program will be needed. posure to low level laser radiation. For visible LASER LIGHT Iaser beams, the risk of ocular damage could be increased at the receiving site if magnifying The biological risks associated with the laser devices were used. Prolonged occupational ex- system have been assessed only to a very Iim- posure at infrared power densities greater than ited degree. The power density of the focused 10 mW/cm2 would be of particular concern, laser system beam would be sufficiently great especially for the cornea. Workers at receiving to incinerate biological matter.”’ Safety meas- sites wouId probably be required to wear pro- ures (such as a perimeter fence and pilot beam tective clothing and eye goggles. system) would have to be devised in order to avoid beam wandering and the direct exposure Hazards outside of the site have not been of the nearby public and ecosystems. Less easy assessed. It is unlikely that wildlife or vegeta- to protect would be birds and insects flying tion at the receptor site would survive.95 The through the beam; without some sort of warn- etfects of the low level laser Iight on eco- ing device they wouId be incinerated.90 It is not systems outside of the receptor area are not known if air-borne biota would be aware of the known It is possible that certain infrared sen- beam, and if so whether they would be at- sitive Insects would be attracted to the laser tracted to or avoid it. Siting studies should beam, but this requires further study .9’ consider migratory flyways and local bird The bulk of research on the biological ef- populations. fects of lasers is not directly applicable to the It has been suggested that aircraft be re- infrared lasers that have been suggested for stricted from the power beam area.91 While it SPS Most studies have concentrated on the is not expected that jets and their passengers effects on the eyes and skin of visible and near would suffer any damage in traversing the infrared lasers in a puIsed mode. The standards beam due to their high speed and infrared re- that have been promulgated pertain predomi- flectivity, slower flying, less reflective aircraft nantly to short-term occupational exposure to could be affected. More important, laser light specularly reflected from an airplane would 92 ——— present an ocular hazard to the public. A ‘ ‘Beverly, op clt radar warning system might be devised to de- ‘“[3 H Sllney, K W Vorpahl, and D C Wlnburn, “Envlron- nlenta I H ea Ith Hazards From H lgh-Powered I nfra red Laser De- “’Beverly, op clt V I <-e $ ‘ ‘ \rch Envlronmenta/ Ffea/th, VOI 30, April 1975, pp ‘OWalbrldge, op clt 174170 9’ Beverly, op clt “‘W~lhrldge, op clt 92 Walbrldge, op clt ““lhl(i Ch. 8—Environment and Health ● 219

lasers operating in a controlled indoor environ- fects would occur. Nonetheless, research ment such as a laboratory or medical facility. should be conducted in this area. The effects Few studies have examined the effects of of changing the night sky also need to be chronic exposure at SPS-like power densities studied for ecosystems both near and distant and under SPS environmental conditions. A from the site. Ecosystems could also be in- summary of known effects on the skin and directly affected by weather modification in- eyes is presented in appendix D. duced by the mirror system.

REFLECTED LIGHT FROM THE MIRROR SYSTEM LIGHT REFLECTED FROM REFERENCE SYSTEM The light reflected by the mirror system to The transportation vehicles, construction Earth would be visible at night as a general and staging bases, and the satellite structure of glow at up to 150 km from the receiving site. ” the orbiting satellite systems will reflect The potential health impact of most concern is sunlight, discernible on Earth. Some specular ocular damage from either the scattered light reflections from reference system components or from direct exposure to reflected light as may be exceptionally bright due to their large the mirror image sweeps across the Earth dur- size, low altitude, and reflectivity. 1oo Most ing orientation maneuvers. Since the CoIIective specular reflection would be restricted to intensity of all the mirrors at one site would be small, fast moving spots or “glints” as the equal to that present in the desert at noon, it structures and vehicles change orientation. appears that the intensity of Iight would be too The worst cases, which may exceed acceptable low to be of danger to the observer. One in- limits, occur for reflections from the solar vestigation revealed that under the worst con- panels of the OTVS while in LEO, and the back ditions (i.e., staring, no blinking) it would be of the solar panels in CEO. Diffuse reflections, safe to view the mirrors directly for at least 2.4 brighter than most stellar sources would make minutes. ” No information is available regard- the LEO OTV staging base visible during the ing the ocular effect produced when an indi- day It may be possible to reduce most of these vidual views the mirrors with a binocular or reflections by controlIing the orientation, sur- telescope. The psychological effects of a “24- face curvatures, solar panel alignment and sur- hour day” or aIterations of the sky near the face quality of the vehicles and structures. sites also needs to be studied. Reflection of visible light from the components of other SPS technical options may be The ecological impacts have not been as- similar to the reference system depending on sessed. It is known that the polarization, fre- the orbit and size of transportation vehicles quency and intensity of light as well as the and space structures. percentage of daylight hours influence the behavior, navigation, and lifecycle of many The effects on the public and ecosystems species of wildlife and vegetation; many have yet to be evaluated in depth. One study species have inherent biological clocks or cir- found that the reflections from the reference cadian rhythms that are triggered by the diur- system would be bright but not dangerous to nal and seasonal variations of sunlight.99 the human eye101 unless viewed for too long or However, ecosystems in the area surrounding with a magnifying device. Studies would be the receiver site would be exposed to low further needed to evaluate the ground illu- levels of incremental sunlight and so it does mination in terms of human exposure limits not appear Iikely that significant biological ef- and to explore any possible psychological effects While DOE has tentatively concluded that plants and animals would not be unduly 97 Billman, private communlcatlon, op clt ‘*M T Hyson, “Sunllght ReflectIons From a Solar Power Satel- lite or SOLARES Mirrors Should Not Harm the Eyes, ” In The Flr-ra/ “’(’D [ Llemohn, D H Tlngey, and B R Sperber, “Character- Proceeding of the Solar Power .$atellite Program Review, Apr izat lorl of Reflected L Ight From the Space Power System, ” In The 22-25, 1980, DOE/NASA report No Conf -800491, July 1980 Findl Proceed)ngb of the Solar Power Satellite Program Revfew, “McGraw-Hi/l Encyclopedia of Science and Technology, VOI Apr IL 25, 1980, DO E/NAsA report No Conf -800491, ) uly 1980 10 (New York McGraw-Hill Book Co , 1977) ‘‘“ I+v\on, op cIt 220 • Solar Power Satellites

affected by the reflected light, ecosystem ef- Table 46.—Representative Noise Levels fects are largely uncertain. More research Due to Various Sources

would be needed to investigate how altera- Source or description of noise - Noise level (db) tions of the day and night sky could influence Threshold of-pain ...... 120 behavior, navigation, and Iifecycles of wildlife Riveter 95 and vegetation. Elevated train” ...... 90 Busy street traffic...... 70 Ordinary conversation ...... 65 Noise Quiet automobile ...... 50 Quiet radio in home ...... 40 Noise is generated during rocket launches Average whisper ...... 20 and the construction of receiving stations. Rustle of leaves...... 10 Threshold of hearing ...... 0 With respect to the latter, the highest noise — —. — levels would result from heavy equipment SOURCE Errv/ronrnenfa/ Assessment for tire Satelllte Power System Concepf used to prepare the site and build the support Development and Evaluatlorr Program, DO EIER-0069, August 1980 structure. The DOE prototype siting study con- concluded that launch noise wouId not inter- cluded that it would be unlikely that signifi- fere significantly with speech (interruption for cant noise-related impacts on the public and 2 minutes at 30 km twice a day), but that inter- most animals located 2 km or more from the ference with sleep could occur 30 km from the prototype construction site would occur. ’02 site Table 47 presents an estimate of the For some machinery, occupational noise number of people annoyed by the noise as a standards would be exceeded. Mitigation function of distance. Sonic booms would also measures include ear protection devices, muf- be generated; pressure levels are shown for flers for machinery, and special insulation in HLLVs and PLVs in table 48. The HLLV sonic factories. booms would not cause injury but would in- Very high noise levels would be associated voke gross body movements and might inter- with launch vehicles during ascent and reentry. fere with sleep. It has been suggested that the Table 45 presents the estimated noise pro- trajectories of launch vehicles should avoid duced by the HLLV. Table 46 is exhibited for population areas. comparison. A preliminary assessment indi- The effects of noise on wildlife include star- cates that the OHSA standard of 115 db(A) tle responses and disruption of diurnal and would be exceeded within 1,500 m of the reproductive cycles that could be particularly launch pad, and the EPA guideline violated significant in endangered species habitats. It within 3,000 m.103 Using the Kennedy Space has been suggested that wildlife would adapt Center as a prototype launch site, the study 4 to the noise, but this is not clear. ’0 While the noise generated by the space shuttle is not ex- “)’ Protot ype Envlronmenta/ Assessment of the /mpacts of $Irlrrg and Construct~ng a Sate//fte Power $ y~rem ( SP$) Ground /7ecelv- pected to be serious, the effects of HLLVs Irrg Stat Ion (C RS), op c It wouId be greater because of the increased fre- “’JEnvlronmenta/ Assessment for the \ate//lte Power System — —.. Concept Development and Eva/uat/on Pro#ram, op clt “ ‘Ibid

Table 45.— Estimated Sound Levels of HLLV Launch Noise —— Distance from launch pad . Sound level and duration 300 m 1,500 m 3,000 m 9,000 m 30,000 m OASPL a (dB) ...... 149 136 130 120 109 A-level b [db(A)] ...... 130 114 105 89 72 Duration(s) ...... 12 42 54 77 77 aOASPL: overall sound pressure level expressed In decibels (db) above the level corresponding to a reference pressure of 20 pa (pa= Pascal = 1 N/mz) bA-ievei: Weighted average sound level over the frequency spectrum In accordance with the Performance of the human ear

SOURCE: Env/ronmenta/ Assessment for the Sate//lte Power System Concept Deve/opmerrf dftd Eva/uat/on Program, DOE/ER-0069, August 1980 Ch. 8—Environment and Health Ž 221

Table 47.–Community Reaction to HLLV decrease in ozone corresponds to a 2-percent Launch Noise increase in biological harmful ultraviolet radiation that reaches the Earth, 107 the effects Percent of people highly Distance from launch point (m) annoyeda of SPS on the ozone layer has been studied. 300 ...... 90 preliminary analysis concludes that the change 1,500 ...... 45 in ozone brought about by SPS launch efflu- 3,000 ...... 24 ents would be negligible, but further study is 9,000 ...... 5 108 30,000 ...... 1 requ i red. aBa~edon a24.hraverage of thenowe The deployment of SPS would also require SOURCE Env/ronmenta/ Assessment for the Sate///(e Power System Concept the mining, production, and transport of cer- Deve/opmentand Eva/uat/on Program DOE/ER-0069, August 1980 tain toxic materials. Some toxic materials such as hydrocarbons could also be released from Table 48.—Sonic Boom Summary (Pa) fuel burning in the launch and recovery of ——— space vehicles. Rocket propellants such as liq- Vehicle Launch Reentry u id hydrogen are of special concern because HLLV booster . ‘1 ,200 190 they are toxic, flammable, and explosive. 109 A HLLV orbiter ...... — 140 PLV booster...... 770 140 spill of liquid oxygen would adversely affect PLV orbiter...... — 70 local ecosystems. However, no information is

SOURCE Env/ronmenfa/ Assessment–for the Sate///te Power System Concept available to quantify the exposure or risk to Deve/opmenf and Eva/uat/on Program DOE/ER-0069, August 1980 the public, workers or ecosystems. An incremental increase in the risk of catastrophic ex- plosions or fire is thought possible, especially quency and level of noise, due especially to because of the large amount of fuels involved; sonic booms. the occupational risk, of course, being consid- Terrestrial workers would be exposed to erably higher than that for the public. noise levels higher than the general public and Launch and recovery accidents are not likely wouId require hearing protection. 105 Possible to have any more impact on the public than hearing damage and pyschological effects conventional aircraft accidents, although it should be studied in Iight of the unprece- has been suggested that flight trajectories dented frequency and size of launches. avoid populated areas. The noise and shock waves from a catastrophic explosion of an Other Risks HLLV could possibly blow out windows and doors in buildings up to 15 km from the launch Quantitative studies are needed to deter- pad ‘‘ mine SPS impacts on air and water quality and the generation of solid wastes. It is currently Space Environment assumed that these impacts would be comparable to typical industries and powerplants (ex- Many space workers would be needed to cept coal) and that unusually high risks would construct and maintain an SPS system. The not be encountered by the public and terres- reference design, for example, requires 18,000 trial workers that could not be minimized or person-years in space; 112 workers would serve )() corrected. ‘ The effects on ecosystems are ten 90-day tours over 5 years. Other SPS de- less certain. signs may have different personnel require- DOE has concluded that acid rain from the ments, but they will not be specifically ad-

SPS launch ground cloud would be localized, “)’} Hamer, “Ozone Controversy, ” Editor/a/ Research Reports, temporary and minimal. Because of the conse- VOI 1, No 11, 1976 quences of ozone depletion, i.e., a l-percent ‘ ‘“l bl[i ““l bld ‘ “)1 bid “)’lbld ‘ ‘ ‘ Ibid “’hlbld ‘‘ ‘Program Assessment Report, Statement of Findings, op clt 222 • Solar Power Satellites

dressed here. The health effects of the space considered, the health and safety of space per- environment are potentially serious, but highly sonnel should be a high-priority research task, uncertain; experience with people in space is The principal health and safety risks of the limited to a few highly trained astronauts who space segment of SPS are illustrated in figure lived mostly in LEO for a maximum of a few 43. Effects on the general health and safety of months. 113 NASA’s current ground-based pro- space workers such as acceleration and gram as well as future activities with the space weightlessness are discussed in appendix D. shuttle and space operations center will yield information relevant to SPS space worker The most serious potential health risk of the health and safety. DOE does not consider the space environment is exposure to ionizing radi- potential health effects an obstacle to con- ation. The types of radiation found in the tinued planning and development of SPS, 114 different SPS orbits are listed in table 49. but if this and other space projects are to be Exposure to radiation in CEO and in transit between LEO and CEO are of most concern because, under the reference system scenario, workers spend approximately 91 percent of

Figure 43.— Factors Pertinent to Space Worker Health and Safety

Space structure charging High voltages Electric and \ / Construction

Transport ce debris accidents eoroids

accidents

Construction accidents o

Space debris Life p failure Transport accidents

transport accidents acceleration/deceleration

SOURCE Program Assessment Report Statement of Findings Satelltte Power Systems ;oncept Development and Evaluation Program, DOE/NASA report No DOE/E R-0085 November 1980 Ch. 8—Environment and Health ● 223

Table 49.—Types of Radiation Found in the Estimates of the radiation dose for exposed Different SPS Orbits SPS space workers are uncertain. Few measure- GEO ments have been made of the radiation fIux in 117 ● Radiation belts GEO. It is also difficult to quantify the radi- —Electrons—dominant when shielding is less than ation levels at any one time because solar 3gm/cm2 aluminum —Bremsstrahlung —produced by electron interactions with storms that significantly increase the levels are shielding—dominant when shielding is greater than currently impossible to predict. Moreover, 2 3 gm/cm aluminum there is considerable controversy over the —Protons—low energy—stopped by minimal shielding ● Galactic cosmic rays models that are used to estimate the amount —Protons of energy absorbed in the human body as well —Helium ions as the biological consequences of the ab- —High-energy, heavy ions 118 ● Solar particle events— i.e., particles accelerated to high sorbed radiation. The most significant long- energies during a solar f I are term effect of ionizing radiation is cancer. —Protons Cancer risk depends on a number of factors in- —Heavy nuclei cluding the total I-fetime dose-equivalent; Travel Between Orbits • Radiation belts dose rate; duration of exposure; and the age, —Bremsstrahlung radiation produced by electrons sex, and susceptibiIity of the exposed —Protons person. 9 LEO . South Atlantic Anomaly DOE has estimated that space workers for —Protons the SPS reference design (which includes mod- —Electrons—low energy—stopped by minimal shielding est shielding— 3 g/cm2 aluminum for habitat SOURCE: Margaret R. White, Lawrence Berkeley Laboratory, private com- 2 munication, Feb. 12, 1981 and work stations and 20 to 30 g/cm for the storm cellar, used during solar particle events) their time in the higher orbit where the radia- would receive 40 reins per 90-day tour or 400 115 tion environment is the most severe. In GEO, reins for the planned 10 tours.120 This estimate except under the unusual circumstance of a could be inaccurate (probably too high) by a large solar flare, the major part of the radia- factor of 5 or 10.2’ However, the biological im- tion dose in the reference system would be due pacts could actually be higher than this dose to bremsstrahlung produced by the interaction wouId indicate if HZE bioeffects are taken into of high-energy electrons with the shielding account and/or a solar particle event occurs. I n material. The biological effects of this kind of spite of the large uncertainties, it is almost cer- radiation are reasonably well understood, and tain that reference system exposure would ex- innovative shielding might reduce this dose. ceed current Iimits for radiation workers as radiation from the high-energy, However, recommended by the National Council on Ra- heavy ions (HZE) in galactic cosmic rays can- diation Protection and the International Com- not be stopped by conventional shielding and 122 mission on Radiological Protection. For their biological effects are currently very comparison, the general popuIation receives poorly understood. From theoretical con- 123 about 0.1 rem/year on the average; occupa- siderations and preliminary experiments it appears that they may be much more effective in ‘ 7M~rgaret R White, Lawrence Berkeley Laboratory, private causing biological damage than other types of communlcatlon, Feb 12, 1981 ‘‘ “Program Assessment Report, Statement of Findings, op. c It ionizing particles. Thus, though they con- ‘ “1 1 Lyman, “Hazards to Workers From Ionizing Radiation tribute a small fraction of the total radiation In the S PS E nvlronment, ” in The Final Proceeding of the Solar dose in the reference system, they are of major Power $ate//ite Program Review, Apr 22-25, 1980, DOE/NASA report No Conf -800491, July 1980 concern with regard to the health of space ‘J{)lonlzlng Radiation Risks to Sate//lte Power .Systems (SPS) workers.116 WorLer>r op clt ‘” Program Assessment Report, Statement of Findings, op clt ‘ “ionizing Radiation Risks to Satellite Power Systems [SPS) ‘‘Zlbld Workers, LBL-9866, November 1980, advance copy ‘‘ ‘Committee on the Blologlcal Effects of Ionlzlng Radiation, 1“M R White, Environmental Assessment for the Satellite The F f fects on Populations of Exposure to Low Leve/s of Ionizing Power System, Non-Microwave Health and Ecological Effects, Racflat/on (BE/R ///), National Academy of Sciences, 1980, DOE, in press (1981) tvpesc rlpt edltlon 224 ● Solar Power Satellites

tional exposure limits (for blood terming risks associated with the reference system organs) are 3 reins for 90 days and 5 reins over couId be reduced with additional or innovative 1 year;124 and the NAS maximum recom- shielding. Analysis is needed to determine if mended exposure limit (for bone marrow) for better shielding techniques can be devised that astronauts is 35 reins for 90 days, 75 reins over would not incur a greater weight or cost pen- l-year period and 400 reins for Iife.125 If space alty. Studies are also needed to examine to worker careers were 5 years, with 90 days in what extent additional shielding mass will in- space alternated with 90 days on Earth, it crementally reduce risks of exposure to most would be expected that for each 10,000 radiation (because secondary radiation can be workers in space, between 320 to 2,000 addi- produced as the thickness is increased),129 or if tional cancer deaths in excess of normal can- shielding materials can be developed to stop cer mortality would occur.126 An issue critical HZE particles. to SPS design and economics is whether the DOE has concluded that as presently de- radiation standards developed for astronauts signed, the reference system construction should be applied to SPS workers.127 scenario is unacceptable.130 Risks could be Risks could be reduced in a number of ways. reduced if personnel spent more time in LEO. For example, the time per tour and the number More study is required to improve the current of tours per worker could be decreased. Ro- assessment and to explore the impacts on the bots and teleoperation could be used to re- system Cost and feasibility of modifications of duce the number of people required in space. the reference system in order to minimize ion- It is also essential that accurate, quick and izing radiation hazards. rugged dosimeters be developed that monitor I n sum, research priorities include: the real-time radiation flux and energy levels to which each individual is exposed.128 in- ● measurements of radiation flux in CEO. struments would also have to be developed to This can be done with CEO satellites; the warn personnel in GEO of solar storms or other space shuttle and space operations center unforeseen high radiation events so that they wilI provide data on LEO; can move to shelters. Considerable improve- ● study of the bioeffects of HZE particles; ments in dosimeter technology are needed ● continued study of radiation bioeffects since present devices are not very accurate and refinement of models; and take a long time to display radiation ● improvement in dosimetry techniques and levels. Shielding is also crucial Some of the shielding technology; and ● for SPS, improved analysis of exposure ’24W Schimmerling and S Curtis (eds ), Workshop on the Radi- risk, and shielding techniques, considera- ation Environment of the Satellite Power System (SPS], Sept 15, tion of exposure limits, and assessment of 1978, DOE, Conf -7809164, December 1979 1251b;d the viability of workers in space: tradeoffs

‘2’Whke, Environment/ Assessment for the Sate//ite power between human health, system feasibility, System, Non-Microwave Health and Ecological Effects, op cit and economics. ‘*’Program Assessment Report, Statement of Findings, op cit ‘2’ Environmental Assessment for the Satellite Power System 12“ProgrJm Assessment Report, Statement of Findings, op cit Concept Development and Evacuation Program, op clt ‘ ‘“l bld Chapter 9 INSTITUTIONAL ISSUES Contents

Page Financing, Ownership, and Control ...... 227 Space and Energy Sectors ...... 227 Government-Private Sector Relat ons .., ...... 227 Phases of SPS Development...... 229 Possible Models ...... 230 The Implications for the Utility Industry ...... 23.5 Introduction . . . 235 The Utilities’ Planning Process...... 235 Engineering Implications of the SPS for the Utilities Grid . . . 239 Regulatory Implications of SPS ...... 243 General Implications for the SPS ...... 245 Issues Arising in the Public Arena ...... 247 The SPS Debate ...... 247 Siting ...... 258

TABLES

Table No. Page 50. Characteristics of the SPS System ...... 236 51. Major Grid Contingencies . . .237 52. Potential for Power Variations From the Reference System SPS . . . .241 53. Major Issues Arising in SPS Debate ...... 250 54. Potential Benefits and Drawbacks of SPS “Technical Options . . . 259

FIG U RE

Figure No, Page 44. Phases of R&D ...... 238 Chapter 9 INSTITUTIONAL ISSUES

FINANCING, OWNERSHIP, AND CONTROL

The questions of who would finance, own, Energy and control a solar power satelIite (SPS), and to what extent, are interrelated. As a project that EIectricity is provided by public and private would involve the Nation’s space and energy utilities, which are regional monopolies reg- sectors, as well as several Government agen- ulated by State authorities. R&D and construc- cies, there are numerous issues to be con- tion of generating equipment—turbines, nu- sidered regarding the proper allocation of risks clear reactors, switching gear— is done by pri- and responsibilities. The following discussion vate firms, who sell to utilities. The utilities will examine: 1 ) current policy and structure of operate and maintain equipment, build trans- the space and energy sectors; 2) the relation mission lines, and market electricity to end- between Government and private-sector activ- users Due to severe capital constraints and a ities; 3) the importance of distinguishing be- lack of expertise in space operations, utilities tween the different phases of SPS develop- are unlikely to own and operate SPS in the way ment and operation; and 4) possible historical they currently do with other types of power- and hypothetical models for an SPS project. plants, though they may well be responsible for the ground-receivers. In the case of SPS, there is a question as to who would carry out Space and Energy Sectors these various activities,

Space Although energy production in the United I n the United States, space capabilities have States has traditionally been handled in a been primarily instigated and funded by the decentralized manner by private industry, in- Federal Government (with much of the actual creased sensitivity to the importance of energy development and construction done by private issues since the 1973 oil embargo has led to firms under contract to the National Aero- various attempts at formulating a national nautics and Space Administration (NASA)). energy policy, centered in the newly created Launchers, launch facilities, and tracking net- Department of Energy (DOE). DOE’s scope and works are currently Government monopolies responsibilities in areas such as basic research that may be leased to private companies, and engineering have yet to be determined; Government agencies, or foreign countries for funding is being provided for projects in specified purposes. Only certain payloads are photovoltaics, conservation, nuclear power, built and owned by nongovernmental bodies. synfuels, and other areas. DOE can be ex- Within the Government, NASA is responsible pected to have a prime role in any SPS project. for R&D of civilian space-systems that, when development is completed and the operational Government-Private Sector Relations stage begins, are turned over to another part of What would be the degree of Federal in- Government or to the private sector. Scientific volvement with the SPS at different stages, missions, such as deep-space probes, are run such as R&D, construction, and operation; and by NASA, as are launch facilities such as Cape in different areas, especially financing, trans- Canaveral. Military and intelligence opera- portation and transmission, and marketing? tions are largely separate even in the R&D phases, with control exercised by the Depart- The arguments for Federal involvement cen- ment of Defense (DOD) or specific intelligence ter around fears that the private sector will not agencies. be able to undertake an SPS project, because

227 228 ● Solar Power Satellites

of the very high costs and risks, and the long ments. Uncertainty, whether technical, politi- and uncertain payback period. There is also cal, or economic wilI deter potential investors. concern that private-sector development, even The incentives required to spur any private if economically feasible, might be detrimental interest would in themselves involve draw- because of monopoly by a single firm or con- backs. A company taking a major risk on SPS sortium, and environmental and international would expect to be compensated by exclusive policy considerations requiring public control. patents and other guarantees, in effect with a Cost estimates for different SPS scenarios monopoly. Government regulation would have are very imprecise; the most comprehensive to take risks into account by allowing a very estimates have been done by NASA for the high rate of return, i.e., allowing the owners to reference design and calI for a total invest- charge high rates for SPS electricity. A private ment of $102 billion (1977 dollars) over 22 monopoly charging above-average prices years for construction of the first 5-GW SPS, could prove to be politically embarrassing. i.e., before any return on investment (see ch. 5). An SPS system will require a great deal of The key questions are whether the private sec- political support both locally, nationally, and tor can or would raise these amounts of internationally: land-use conflicts, monopoly capital, and how investment costs and considerations, environmental standards, tax management responsibilities might be shared incentives, and radio frequency allocations are between Government and industry. a few of the political issues that SPS will need Though the reference figures are highly ten- to confront. Private development and owner- tative, the general magnitude of the project ship may be seen as leading to an excessive and its division into discrete stages are likely concentration of power outside effective pub- to be similar regardless of what design is used. lic control None of the alternatives has been examined in nearly the detail of the reference design, large- Difficulties With Federal Involvement ly because the technologies are less well-devel- Any large long-term project, public or pri- oped. The following discussion will focus on vate, dealing with advanced technology may reference figures but should be applicable to suffer from financial and management prob- any SPS system of similar magnitude. lems: lack of coordination between parts of the program; inadequate supervision of con- Difficulties With Private Involvement tractors; financial and production bottlenecks A total investment of $40 billion to $100 in specific areas that delay other parts of the billion over 22 years–with additional much program; inaccurate initial estimates of costs larger investments to build a complete sys- and completion times, and so on. However, tem —would be unprecedented for private-sec- Government programs often have special con- tor financing of a single project. straints that need to be taken into account. Without a profit motive and the discipline of Private capital can be raised by borrowing, responsibility to owners and stockholders, issuing bonds or stocks for sale to the public, there is less incentive to reduce costs. Civil or from profits. Especially in the first years, service regulations can interfere with hiring borrowed funds would be available, if at all, and firing and limit salary ranges, decreasing only at prohibitively high interest rates. Stocks flexibility and making it difficult to retain per- and bonds would be unlikely to attract large sonnel Annual Government funding produces investors when profitabiIity Iies some 30 years uncertainties and leaves programs vulnerable in the future. Both institutional investors and to political pressures and pork-barrel com- large corporations allocate only a small pro- promises. Government-funded R&D in the pub- portion of their funds for high-risk long-term lic domain requires special supervision, since projects; in some cases, such as pension funds, without the incentive of exclusive rights to there are legal limitations on high-risk invest- patents and processes, firms doing research Ch. 9—institutional Issues ● 229

may tend to inflate costs and draw out delivery mercial operation, that internal procedures scheduIes. 1 Any extensive Government funding and structure are appropriate to private owner- could divert funds from other space, energy, ship, and that the transition from development and R&D programs, whose backers might ask to operation proceeds smoothly. for compensation. The SPS would consist of a number of dis- Explicit Federal involvement may increase tinct systems, each of which must be devel- the probability of military participation in oped separately and simultaneously: e.g., some or all SPS activities, complicating most transportation, energy conversion and trans- forms of international cooperation and mission, orbital construction, and ground sta- possibly leading to detrimental changes in the tions launchers and solar cells, for instance, SPS design or operating characteristics. may be useful and profitable regardless of Finally, a federally financed or owned SPS whether SPS is built or not. Should their would increase centralized control over an im- development be charged to SPS? If so, their portant sector of the economy and would lead use and sale might help to offset the risks of to greater politicization of America’s energy the program as a whole; on the other hand, industry. their development adds considerably to the SPS cost. It can be argued that public funding Phases of SPS Development should be reserved for those parts of the project that private investors will not handle and Federal v. private investment is not an that segments with near-term commercial ap- either/or proposition. I n general, Federal in- plications should be left to the private sector. volvement would be necessary in the early As in any complex program, there is the ques- stages, and become increasingly less so, tion of internal apportionment of risks and assuming the system remains technically and benefits. Successful items can help to sub- financially feasible, as the project becomes sidize less profitable projects, provided funds operational. The basic problem is how to dif- are transferable from one division to another, ferentiate between the various and overlap- allowing for risky high-return investments, but ping stages and ensure adequate management also for Edsels. and continuity throughout. In the case of SPS it is essential that each SPS development can be divided into suc- component be developed on time and to the cessive stages (as described in ch. 5): research, proper specifications for the system as a whole engineering, demonstration, and so on. Federal to function. Management must be given suffi- financing and management of the research cient authority to produce appropriate prod- and engineering phases might turn into a com- ucts., even if particuIar divisions suffer; say, if bined Federal-private program as more directly SPS solar cell designs are not optimal for commercial phases were undertaken. The ground-based users. Major investors in a pri- question is at what point and to what degree vately funded SPS wiII have their own particu- private investors will be willing to enter the lar interest–aerospace companies in launch- project. On the one hand, investors would ers, electronics firms in microwave hardware, prefer to see as much as possible paid for by utilities in delivered power — that could com- the Government; but early investors would promise the project’s overall goals. Govern- have an advantage in setting program pri- ment supervision, whether by partial owner- orities and establishing a dominant position. ship, reguIatory oversight, or appointment of Involvement of owners and operators at the d i rectors, may mitigate certain confIicts but is earliest possible stages would help to ensure no guarantee of smooth saiIing. Federal con- that the completed system is suited for com- cern for a broadly conceived public interest may be affected by a desire for continued con- I Mark Cersovltz, “Report on Certain E conornlc Aspects of the SPS Energy Program, ” OTA ( ontrdf I No ()} 3-26700, 1980, pp trol and supervision, or by the interests of par- 1719 ticuIar agencies. For instance, DOD may place 230 ● Solar Power Satellites

emphasis on booster and LEO to CEO trans- operates specific faciIities (on a cost-reim- port development for its use (see ch. 7), bursable basis) for research and launches. perhaps affecting launcher design or the allo- ● Advantages. – NASA is already in place, with cation of program funds. NASA may wish to 22 years of experience. It has well-estab- emphasize and prolong the R&D phase. An- lished relationships with private contractors, nual budget review may increase costs by cre- other parts of the Government, and foreign. ating uncertainty and requiring project mana- companies and Government agencies. It has gers to spend large amounts of time drawing the technical and administrative expertise to up and justifying annual budgets. evaluate most of the major components of the SPS, many of which— interorbit transfer Possible Models vehicles, assembly and construction facilities — are part of current NASA plans. Perhaps the best way to further examine possible financing and management scenarios ● Disadvantages. –Annual funding for NASA is through historical and hypothetical models projects creates difficulties in implementing that might be applicable to SPS. In each in- long-term plans that are likely to go in and stance there are several questions to be asked: out of political favor. It also hampers 1) Is it complete: can this model support an agreements with foreign firms and agencies, SPS program from start to finish, or is it ap- that have had problems in the past when plicable only to certain phases or components? NASA budget cuts have forced cancellation 2) How are risks apportioned: who pays, and of joint programs. Legislative changes to who reaps the benefits of a successful project? permit ongoing funding would greatly im- 3] How efficient and flexible is it: can it adapt prove NASA’s position. to changing economic and technical circum- NASA’s emphasis on R&D and prototype stances, and can it attract support from a development (NASA’s ability to participate variety of sources, particularly foreign in- in commercial ventures is unclear and sub- vestors? ject to restrictions) could create problems in developing a commercial product such as Historical Models SPS; NASA might have to relinquish control NASA after the demonstration phase. There is often reluctance to complete R&D phases, NASA is an independent Government since completion means loss of the project. agency with a general mandate to engage in Coordination with eventual users and own- R&D and testing and to conduct launches for ers may be underemphasized. Amending civilian space activities. Although NASA has in NASA’s charter to allow for beginning-to- the past centered its efforts on high-visibility end development and operation would alle- manned projects, such as Apollo and the viate this problem, but might be harmful to Space Shuttle, it has also conducted major the agency’s R&D mission. programs in telecommunications, remote- The broad scope of NASA activities has sensing, and the sciences, such as the Viking meant that, within and without the agency, and Voyager interplanetary probes. there have been conflicts over the relative NASA is funded by general tax revenues ap- priority of scientific v. applications, or propriated annually by Congress. NASA funds manned v. unmanned missions. The SPS are overwhelmingly—90 to 95 percent— spent could be criticized for diverting funds and on outside contracts with private firms, re- attention from competing programs; intra- search centers, and other Government agen- agency squabbling might interfere with the cies, foreign as well as domestic. NASA itself project. Excessive concentration on SPS helps to set priorities and policies, oversees could prevent NASA from accomplishing and coordinates contractor performance, and other tasks, although many aspects of SPS Ch. 9—Institutional Issues . 231

development would be applicable to other in having it undertaken by an established space activities. agency. Funding all, or even a large part, of the ● Disadvantages. — It is not clear at what point SPS through general tax revenues would pro- private financing would become available duce strong pressure for continued Govern- on a large scale, and hence how much must ment control. Since the risks are borne, in- be spent out of general taxes. The larger the voluntarily, by the general public, justifica- public part of the investment, the more tion in the form of visible public benefits likely are the public-interest problems may have to be provided. These benefits outlined previously. couId take the form of electricity-rate reduc- Financing through bonds does not provide tions, tax-reductions, or other types of for the type of accountability available returns. Turning SPS or SPS technology over through congressional appropriation, or to private profitmaking firms may be unac- through public ownership via the stock mar- ceptable. Such a prospect could discourage ket Specific arrangements for public over- private interest; this difficulty is common to sight, given the monopoly position of such all publicly financed ventures. an entity, would have to be made. Owner- TENNESSEE VALLEY AUTHORITY (TVA) ship of patents and products generated by public investment would have to be clari- TVA, the Nation’s largest utility, was estab- fied, given the possibility of competition be- lished in 1933 to provide power for a region tween private firms and the authority in the that commercial utilities were not willing to latter stages of development and operation. develop. Until 1959, TVA received annual Federal appropriations; since then it has raised HIGHWAY TRUST FUND capital by issuing bonds, the amount of which Since 1956 the Federal Government has is subject to congressional approval, as well as spent over $7.5 bill ion (in current dollars) to by charging customers for its services. At that finance the Interstate Highway System and a time, TVA was forbidden from expanding its number of other road and highway programs. service area, in order to avoid competition The money for these investments has been with private utilities. In 1978 TVA’s borrowing channeled through the Highway Trust Fund, authority was raised to $30 billion.2 A TVA- which receives revenue from taxes on gasoline type independent authority, initially financed and diesel fuels, on heavy trucks, and other by tax revenues and authorized at some point sources. These funds are not spent by the to issue self-backed bonds, could be a possible Federal Government, but apportioned to the model for SPS development and operation. States to pay for their share of highway Ž Advantages. — Initial Federal financing systems. would allow for pursuit of R&D and proto- The rationale for Federal financing was that type development. Adoption of TVA prac- an improved road-system would aid the Na- tices, such as the absence of civil service re- tion’s defenses, as well as improve commerce quirements, would free the authority from by decreasing transportation costs. The system certain Government inefficiencies. Issuing was planned on a national scale, but takes ad- bonds would subject the issuer to the finan- vantage of existing State highway departments cial judgments of investors and make the to implement the proposed network. No cen- risks of the project more palatable, since tral construction or maintenance firm was much of the investment would be voluntary needed 3 rather than by congressional or executive decision. The concentration of a newly The distinctive feature of the system is its established authority on a single-project use of specific taxes on a commodity directly wouId avoid the internal conflicts inherent related to the project. Through the tax on gaso-

“’increasing the TVA Bond Celling, ” hearings before Senate ‘Porter (’ wheeler, Hjghwa y A \\[jtance Programs A Ffl\torlca/ Environment and Publlc Works Committee, Feb 23, 1979 ~~erfpf,( ~lve, Congre$slonal Buclget Of flee, FebrUaw 1978 232 ● Solar Power Satellites

line and diesel fuel, transport users have con- oil by 1992. The corporation is instructed to do tributed in proportion to their total trans- so by, in decreasing order of preference: 1) portation expenditure. An additional tax on price guarantees, purchase agreements, or heavy commercial trucks has ensured that loan guarantees; 2) loans; 3) joint ventures. The large users, who were responsible for a high corporation’s goal is to faciIitate private-sector proportion of maintenance costs, would con- synfuel production, and to produce synfuels it- tribute appropriately. Unlike tolls or direct selt only as a last resort. Initial funding was set fees for highway usage, revenue could be col- at $20 billion, with total funding of up to $88 lected before the roads themselves were com- billion envisioned. Funds are to be provided pleted. An analogous tax to finance a fund for from the windfall-profits tax on domestically SPS might be levied on current domestic and produced oil. 5 commercial electricity consumption (though A possible SPS corporation would resemble from a strictly financial point of view the tax the Synfuels Corp. in being a high-cost energy need not be directly related to energy con- production plan with a specific goal and time- gumption. ) table It would differ in that it would involve ● Advantages. —The use of a designated tax creating a single firm rather than funding nu- provides more assured and predictable fund- merous private enterprises. ing than general revenue taxes that need to ● Advantages. — The Synfuels Corp. has the ad- be reallocated on a yearly basis. By taxing vantage of a discrete goal and timetable, electricity consumption the costs would be with maximum flexibility as to achievement. borne by the future beneficiaries of SPS. If The etmphasis on price and loan guarantees desired, taxes on other forms of energy to encourage rather than replace conven- could also be imposed; all energy taxes tional financing arrangements should re- would have the added benefit of encourag- duce the cost, assureing projects are suc- ing conservation. As private investment was cessful. Direct Government control will be found, the tax could be reduced, or revenues avolded, unless no private ventures what- couId be spent elsewhere. ever are forthcoming. The size of the tax, if levied on electricity alone, would not have to be large to gener- ● Disadvantages. – It is far too early to tell ate significant revenue. A tax of 2 mills/kWh whether the Synfuels Corp. will accomplish would produce over $4 billion per year (at Its goal, or wiII do so without exorbitant current consumption rates) while raising costs Critics fear that an indiscriminatory consumer costs by less than 5 percent.4 ‘shotgun“ approach may result in funding numerous uncompetitive ventures, in the ● Disadvantages. — A tax on electricity may hope of finding one that works; while the cause consumers to switch to other forms of revenue taken from the oil companies in energy, harmin utilities Higher electricity g taxes may prevent the development of addi- costs will inflate prices of electricity- tional fuel sources. The promise of “easy” intensive products, such as alum inure. Government money and soft loans may dis- The organizational framework to manage courage efficient financial and managerial the SPS will have the same difficulties as practices. other Government agencies, especialIy in While the Synfuels Corp. can pick and handling the transition to private ownership. choose from a number of relatively well- U.S. SYNTHETIC FUELS CORP. developed and predictable projects, the SPS Corp would have to generate its own The Synfuels Corp. was established in June organization. The SPS Corp. couId not, espe- 1980 with a specific mandate to produce the cially at first, simply be a channel for fund- equivalent of 2 million barrels per day of crude ing to private firms, or for loan guarantees. — -- —---- ‘Peter Vajk, SPS FInancIa/, Mandgernent 5( en,]rlo~, DO F con- ~ n(’r~~ $~)( (/r/[y A et, Publ IC Law %9,24, 96th Cong , j une )(), tract No EC77-C-01 -4024, October 1978, p ;6 19H() ill [{ Ch. 9—institutional Issues ● 233

COMSAT have many of the difficulties already men- Comsat was founded in 1962 as a federally tioned. chartered corporation to establish and run satellite communications (see ch. 7). Comsat PRIVATE JOINT-VENTURES did not receive direct Federal funding, but was A private SPS project could be undertaken given the fruits of extensive and continuing either by an established firm, a new company, NASA research on telecommunications satel- or a joint-venture of existing companies and lites,6 as well as the right to use NASA launch financial institutions. For the reasons men- services on a reimbursable basis (which does tioned (high cost, uncertainty, long period not reflect R&D costs). The Government re- before payback, and too many eggs in one bas- tained a measure of control through Comsat’s ket) no single firm, whether new or established, operating charter and by appointing board iS Iikely to undertake SPS development un- members, who were initialIy divided between aided Government, communications common carri- A joint-venture or consortium is formed ers, and private investors. Capital was raised when a single project or enterprise is of in- by issuing stock, which from the outset was terest to several parties, no one of which is well-received by investors. As of 1979, Comsat wilIing to finance or manage it on its own, as stock was held overwhelmingly by noncom- with the Alaskan pipeline. Or, companies may mon carriers; 3 of 15 Board members were be legally prevented from exercising sole own- Presidential appointees, the rest being elected ership for antitrust reasons, while a single by stockholders. system may be technically desirable. For in- ● Advantages. — A Comsat-styled SPS corpora- stance, the Federal Communications Commis- tion would be independent of direct Govern- sion (FCC) required Comsat and IBM to add a ment control and free to operate as a pri- third partner (Aetna Insurance) when forming vate, profitmaking corporation. Government Satellite Business Systems (SBS). In any con- supervision would be provided without the sortium, partners are Iikely to have a particuIar need for onerous restrictions. Comsat has interest in the consortium’s success above and been highly successful internationally via its beyond immediate profitability. In SBS’s case, participation in lntelsat, and a “Solarsat” IBM Corp. and Aetna intend to be major corporation might find it easier to engage in customers of the system, and IBM Corp. will international activities than would a Gov- suppIy operating equipment. 7 ernment agency. Such an organization could ● Advantages. — Potential major partners in an inherit the results of Government-financed SPS consortium would be: aerospace com- R&D and engineering with less of a political panies, oil/energy firms (including possible outcry than if control were to be turned over emergent industries in photovoltaics, syn- to established private firms such as aero- fuels, or other energy sources); and electric space or oil companies; Comsat was estab- utiIities. A consortium that could draw on lished in large part to prevent AT&T from the resources of firms in these major indus- gaining a satelIite communications monopo- tries would find it easier to borrow money, ly. selI stocks and bonds, and use profits for ● Disadvantages. — Issuing common stock SPS investment. According to most esti- would not suffice to raise capital for the mates, the utility industry alone will be early development stages. The transition spending hundreds of bilIions of dolIars over from Government to private funding would the next 30 years to replace old generators and build new capacity; an SPS project ‘NASA communications research was phased out under the wouId not constitute an unmanageable pro- Nixon admlnlstratlon, which looked to Comsat and the private portion of total industry investment, sector to maintain U S preem Inence In commun Icatlon satel I tte technology However, In 1978 the Carter admlnl~tratlon —.— reinstated NASA’s leading role In communlcatlon> R&D, largely ( ourt Upholds SPS, ” Avlatlon Week and Space Technology, to offset foreign government R&D effortj Vldr 1 ( I 1980, p 22

83-316 0 - 81 - 16 234 ● Solar Power Satellites

● Disadvantages. – However, there would still wish to support SPS could sell their stock for be difficulties in funding the initial phases. immediate returns. While aerospace and electronics firms Although such a scenario has the advantage wouId begin to benefit relatively early in the of diffusing SPS ownership, it is difficult to see project, oil/energy companies and utilities how SPS shares would retain their full value on (that have the bulk of the resources) will see the market; if they did, funding via taxes would returns only towards the end. utilities in par- not have been necessary in the first place. ticular, as part of a publically regulated in- Shareholders would instead be left with deval- dustry, will find it difficult to set rates so as ued pieces of paper, unless they are purchased to raise funds for R&D or speculative pur- by the Government —with tax dollars — to poses, as opposed to purchase of more es- maintain a reasonable price. This would tablished technologies. For instance, the $2 amount to a straightforward Government sub- billion Great Plains coal gasification project sidy. was to be financed by a surcharge on gas rates charged by consortium members. Al- STAGING COMPANY though DOE approved the rate hikes, cus- The staging company is essentially a boot- tomers — such as General Motors—and strap operation whereby sufficient revenues State officials protested against being asked are generated during the R&D phase to attract to subsidize synfuels investments.8 The Fed- further capital. The firm would invest its initial eral district court then disallowed DOE’s ac- funds in existing aerospace and high technol- tion, effectively blocking the project. ogy companies, gaining patent rights and new Consortia are more likely to arise in the in- technology—via joint ventures—as well as vestment and operation phases, when indi- conventional investment returns. The success vidual members’ interests are more clearly of the company’s first investments, and its in- defined, and risks have been reduced. The creasing expertise, would attract further very high costs and large size of a full-scale speculative investors; the staging company is SPS system, as well as the monopoly dangers in effect a mutual fund. Eventually, the com- of a system under the control of single company would begin to finance SPS R&D directly, pany, may make inter- or intra-industry con- concentrating on those aspects with near-term sortia attractive. returns. At some point conventional financing would become available for the investment Hypothetical Models and operation phases. In discussing possible SPS financing sce- Such an approach is unlikely, unless its first narios, some writers have proposed completely investments turn out to be in budding Xeroxes novel methods with no historical precedent. or IBMs, to raise the $33 billion estimated to Foremost among them are the Taxpayer Stock be necessary for the reference design R&D and Corp., a new form of Government financing; prototype phases. In 1978 Christian Basler and a private approach, the staging company.9 established International Satellite Industries, TAXPAYER STOCK CORP. Inc., to test his concept; it failed when neither New York nor California would allow ISI stock Under this method, taxpayers would receive to be sold. 10 shares in a public corporation, financed by general tax revenues, in proportion to the percent of taxes used to finance SPS. Shareholders Conclusions could then trade their shares on the market, as It is clear from the review of possible models with any other corporation. Those who did not that there are many ways to finance the latter stages of a successful SPS program, but that

‘Robert D Hershey, “Gasification Plant Rising Amid Many Snags, ” New York Times, Nov 17, 1980, p 1 ‘(’(’ onversatlon with Stephen Cheston, President, Institute for ‘For further discussion see Vajk, op clt , pp 32-40 the \oclal \clence Study of Space, December 1980 Ch. 9—lnstitutiona/issues . 235

the initial phases would in all likelihood have Second, at all phases careful attention must to depend on some sort of Federal funding. be given to public policy concerns: environ- Some combination of the suggested methods mental protection, regional interests, and mili- may prove attractive. tary involvement. Private companies must not think SPS can be developed in secrecy or with- In establishing an SPS organization, atten- out reference to a wide public environment tion should be paid to several factors. First, (see ch 8, Issues Arising in the Public Arena). there should be provisions for stopping the project if it becomes unfeasible. Large initial Third, early and continuous efforts should investments wiII create considerable momen- be made to involve and inform potential inter- tum, which may cause wasteful development national partners to attract investment aid, to continue unless authority is given to ter- forestall competition, and ensure that the minate. This is especially true for Government global market for SPS is kept in mind when enterprises. technical and managerial decisions are made. A narrow focus on domestic concerns, by Gov- ernment or industry, may jeopardize SPS un- necessarily. (see ch. 7, International Implica- “Gersovitz, p 36 tions).

THE IMPLICATIONS FOR THE UTILITY INDUSTRY

Introduction of a new plant render it highly unlikely that the SPS could become part of utility grids until The interest of the utilities in the SPS would several years after a commercial prototype depend on technology related factors such as were built. Although SPS could force some reg- stability and reliability, as well as those more ulatory changes, there seem to be no strong directly related to the economics of electricity regulatory barriers to implementing SPS. generation and distribution (i. e., siting, capital investment and Government regulation). Each Table 50 summarizes the projected charac- of these factors would require more study as teristics of the SPS that would be of interest to more is learned about the various SPS alterna- the electrical utilities. tives. From what is now known, it appears that the technical barriers to integrating SPS into The Utilities’ Planning Process the utility grid are solveable, particularly if the units of SPS generated power are of the order The Current Situation of 1,000 MW or less. It is also apparent that for Because of the recent rapid rise of all energy the utilities to develop sufficient confidence in costs and subsequent efforts to conserve, the SPS, one or more units would have to be tested utilities find themselves in an uncertain posi- over time. tion for the future. In the past, the utilities ex- More troublesome are the economic risks of perienced fairly steady, high peakload growth SPS. When considering adding a new pIant, rates, resulting in a correspondingly high rate utilities must plan far ahead of actual system of growth (7 percent) of generating capacity, a integration for the associated transmission rate that leads to a doubling of capacity every lines and other generating capacity (i.e., in- 10 years. Recently, however, average peakload termediate or peaking plants to supplement growth has fallen sharply. Lower economic the baseload powerplants). Failure of the SPS growth rates and price-induced conservation to meet expected implementation deadlines efforts have had a strong effect on consump- would result in severe economic loss for the tion I n response, the average growth of in- utiIity. The need for extensive trials and testing stalled generating capacity has also fallen. The 236 ● Solar Power Satellites

Table 50.—Characteristics of the SPS Systems

The reference Solid-state sandwich Mirror system 15 System characteristics system” design” Laser system” (baseline SOLARES)

Delivered power from each 135 GW (10 GW satellite (at the busbar) 5,000 MW 1,500 MW 500 MW possible) Total system of...... 300 GW Not projected Not projected 810 GW over 6 Implementation rate ...... 2 per year for — — 7 30 years Start of deployment...... A.D. 2000 2010-2020 2010-2020 2010-2020 (estimate) (estimate) (estimate) Lifetime of each satellite 30 years 30 years 30 years ? Transmission frequency ... , 2.45 gigahertz 2.45 gigahertz 10 microns (infrared) Reflected sunlight — (i.e , microwave) I.e., continuous spectrum Designed capacity factor ., 90 percent 90 percent 70-80 percent ? Rectenna size...... 10 km x 13 km at 6.5 x 5.5kw at 35° Iat. 36 meter diameter 39-km diameter 35° Iat. plus 1 km plus 1 km buffer buffer Terrestrial conversion mode. Microwave dipole Microwave dipole Thermal conversion Thermal, photovoltaic antenna-rectifier and antenna-rectifier and conversion inverters inverters Major potential causes of Maintenance, Maintenance, ecilpses During any thick cloud During any thick cloud Of SatelIite? (max 2 ½ h r interruption. satelIite eclipses cover, maintenance maintenance near equinoxes) (max. 21/2 hr near equinoxes)

1 “’Sa tellite Power System Concept Development and Evalua- (Lockheed Missiles and Space Co , report No LMSC-D67 Mbb, tion Program Reference System Report DOE report No NA5A report No CR-1 7952 ], contract No NASA ;-211 37, Mar 1 ~, DOE/E R-0023, October, 1978 1979 13G. M. Hanley, et al , “Satellite Power Systems (SPS) Concept K W II II I man, W P G I I breath, and S W Bowen, ‘Orbiting Definition Study, ” First Performance Review, Rockwell Interna- Mirror\ t<)r Terre$trlal E nergv Supply, ” In ‘ Radlatlon F nergv Con- tional Report No SSD79-0163, NASA MSFC contract No ver~lon in ~pacej Progre\s In A $tronaut~cj & Aeronauflc\ Serle\, NAS8-32475, Oct. 10, 1979 K W EIII lman (ed ), VOI bl (New York Al AA, July 1978), pp 14 W. S. Jones, L L Morgan, J. B. Forsyth, and J P Skratt, (>1 ~lo “Laser Power Conversion System Analysis: Final Report, Vol. I l,” SOURCE Off Ice of Technology Assessment U.S. total of installed electrical generating tween reserve margins, types of capacity, and capacity in 1978 and 1979 rose by an average reliability requirements. They are also sharply rate of 3.1 and 3.2 percent respectively, rates reducing the amount of new capacity, delaying

that cause a doubling of capacity every 22 Installation of some plants, canceling others, years. Growth rates in some sections of the Although on average the difference between country have been zero or negative in the total capacity and average annual load is same time span. greater than ever before, some industry ex- As the high growth rate of electricity de- ecutives have expressed concern that these mand and subsequent expansion of the utility pl,lnned reductions in generating capacity wi II industry has subsided, the industry has had to Ie,ive the United States seriously deficient if rethink its posture with respect to adding new the current trend towards lower growth of capacity, I n addition to the uncertainties of peak demand reverses itself. others, generally future demand, increasing costs for fuel, more outside the industry, have suggested that in- stringent environmental standards, public op- creased conservation measures can bring the position to nuclear powerplants and techno- need tor new generating capacity to zero or logical changes are also affecting the planning lets, Ieavlng the industry, on the average, in process. What is perhaps of most concern, the posit ion of simply replacing or refurbishing however, is the increasing difficulty private outmoded plants utilities face in raising the large amounts of Planning Process capital needed for building new capacity or U S generating capacity in 1980 was about replacing old, inefficient plants 600 glgclwatts. * The peak load that this capaci- In response, the utilities are placing more — ——. .— emphasis on understanding the interaction be- 1 ~ IX< I ,1, i t t (c; w ] or IJOWpr I \ e(\u,1 I ( 01 ,()()() rmegc)w,itt \ Ch. 9—institutional Issues ● 237

ty is expected to serve is about 410 GW. To After projecting the peak load requirements meet this load, the generating capability is of the system, utility planners add an amount composed of about 10 to 15 percent of peak- of generating capacity equal to that which ing units, 20 to 25 percent of intermediate and might be unavailable because of scheduled 60 to 65 percent of baseload generating units. maintenance. System reliability will then be A planning reserve margin of 20 to 25 percent achieved if sufficient excess capacity over and above peak demand is required to allow the above this amount is available to cover one or utility to continue to serve the customer when more of the sorts of contingencies I isted in any of the operating units fails and when un- table 51.17 This method tends to treat the usual load peaks occur. system in gross terms and does not generally allow for important details of a given system For a given utility system, the reserve is such as the variations of peak load throughout related directly to the expected reliability of the year or the percentage of time it will be the total system. Although the exact amount of t apable of generating given levels of power at reserve needed is currently debated within the tlifferent seasons. For this, a more sophist i- industry, I b the rule of thumb that most utility ( ated analysis would be needed. systems use to calculate their necessary reserve is that they must have no more than one Planning for New Technologies generating outage or failure to meet expected demand in 10 years, a failure that may be as The SPS is one among many new technol- short as a minute or as long as several hours. I n ogies that the utilities are considering in plan- practice, this criterion results in some days of ning for the future. These include regiona/ line voltage reductions and a few days of ap- technologies such as ocean thermal energy peals to customers for conservation, but a very conversion and geothermal; intermediate or low probability of outage in any one year. peaking technologies such as wind, solar thermal and solar photovoltaic without storage; A utility is not simply a set of generating ,~nd baseload possibilities such as advanced plants, transmission lines, and transformers. It coal, breeder reactors and fusion. I n addition, is a complicated interactive network in which ~ome utilities are considering grid connected individual components affect each other dispersed technologies such as solar thermal, through an intricate set of feedback loops. A solar photovoltaics, wind, and fuel cells. Plan- failure in one part of the system may set off a ning for such a mixed bag of technologies is a failure in another part. Adequate reliability is complicated and time-consuming process. As ensured by building enough redundancy into figure 44 illustrates, the time from the initial the system to meet most contingencies, conception of a new technology to actual in- whether from system failure or from unex- tegration into the utilities’ grid can be extreme- pected surges in demand. ly long– up to 40 years or more. Not only must The amount of redundancy required for a utility suppliers develop the components of given system depends heavily on the reliability the individual technology, they must make it of the equipment in the system and the util- technological Iy and economical Iy attractive to ities’ experience with them. To calculate the ‘ Ibl(j necessary reserve, the utilities generally use several methods, the simplest of which, called Table 51 .—Major Grid Contingencies the contingency outage reserve criteria, will serve to illustrate the most important features 1. Loss of the largest generating unit in the system of reserve planning. 2. Loss of the two largest generating units in the system 3. A failure in the largest transmission facility in the system 4. A combination of the above 5. An error of a specific magnitude in load projection “A Kaufman, L T Crane, J r , B M Daly, R J Profozich, and SOURCE A Kaufman, L T Crane, Jr., B. M. Daly, R J. Profozlch, and S. J. S j Bodily, “Are the Electrlc Utllltles Gold Plated?” committee Bodily, “Are the Electrlc Utilitles Gold Plated?” colnmlttee print, print, 96-1 FC 12 Committee on Interstate and Foreign Com- 96-IFC 12. Committee on Interstate and Foreign Commerce, United merce, United States House of Representatives, 1979 States House of Representatives, 1979. 238 ● Solar Power Satellites

Figure 44.— Phases of R&D ● Reliability. – Plants that are highly capital intensive must operate at high capacity fac- I — I tors in order to minimize electricity costs. Thus, numerous forced or unplanned shut- 1000 downs for a given plant would make its technology less desirable. In general, a new technology can be expected to sustain a higher V) 100 rate of forced or unplanned shutdown than G a more mature one. Current mature nuclear s plants and coal plants with scrubbers sustain 10 forced outage rates as low as 15 and 19 percent of their total availability respectively. 1 As the industry gains even more experience, 0 10 20 30 40 it wil I probably be able to reduce this rate Years even more.

SOURCE: R L Rudman and C. Starr, 1978 “R&D Plannlng for the Electric Utlllty ● Ease of Maintenance. — It is extremely im- Industry, ” In Energy Techrro/ogy v Government I nstltutes, Inc , Washington portant to be able to maintain and repair components of the generating system quick- Iy and easily. Nuclear and fossil fuel plants the utilities and, in addition, develop a large currently experience planned outage rates supportive infrastructure. Thus, the vast bulk of 15 and 10 percent, but utility experts of the time spent in the long chain of technol- believe that these rates can be reduced by ogy development is in the phases following several percent. Here again, mature technol- scientific feasibility— newly conceived tech- ogies fare better than newer ones. However, nologies are not I ikely to fill near-term supply the percentage of maintenance doesn’t tell deficiencies. the whole story. The timing of the mainte- Assuming that an engineering demonstration nance is also important. If it is possible to of a new technology is successfu 1, its ultimate plan maintenance during periods when elec- fate would depend on several factors whose in- tricity peak loads are lower, the adverse ef- fluence can only be seen dimly at the time fect on the utility is thereby reduced. when scientific feasibility is proved. Com- RESOURCE AVAILABILITY parative costs are a prime consideration, but public acceptance, the complexities of the Here, fossil or other depletable energy technology, and the ease with which it can be sources wil I suffer in competition with re- integrated into the existing utility infrastruc- newable sources such as wind-, solar-, fusion-, ture are also important (see ch. 6). The utilities or breeder-generated fissile material. Further, use some or all of the following criteria to because the Sun or wind are more available in judge a new technology: 18 some regions of the country than in others, terrestrial renewable technologies wil I vary in ECONOMIC CRITERIA their attractiveness. ● Cost to the User. — Bus bar costs are important but an expensive long-distance trans- SYSTEM CAPABILITY AND FLEXIBILITY mission and distribution system may price a ● Control and Operating Characteristics. — The technology that is otherwise competitive at more stable a power system, the better. the busbar out of the market. This problem Short-term transient outages must occur could apply to any very large, highly cen- under conditions that allow the utility grid tral ized faci I ity. to accommodate them as a matter of course. ‘“R L Rudman and C Starr, “R&D Plannlng for the Electrlc Utility Industry,” In f nergy Techrro/ogy V (Washington, D C ——— Government In$tltute$, I nc , 1 978) “1 bld Ch. 9—institutional Issues “ 239

● Ability to Tolerate Abnormal Events. –A sys- Iector would be based in space. Others are tem that is otherwise acceptable to the characteristic of all large-scale baseload utilities may fail to be adopted because it is technologies. In this section, we will proceed easily disturbed, i.e., small perturbations in through each technology, citing the most im- operating mode lead to wide swings of elec- portant effects each alternative will have on trical output. the utilities.

● Unit Rating. –Although economies of scale The Reference System are very real in generating equipment, smal Ier capacity units may often be desir- ● 5,000-M W Capacity. – Because of the grid able, because they are easier to repair and reliability requirements, the large size of the replace than the large ones. reference system plant would limit the number of individual utilities or utilities’ systems ● Environment/ Issues. — Environmental im- that could accommodate it. As a rule of pacts produce an economic cost that, while thumb, a utility generally will not purchase a often impossible to specify, have a strong ef- single unit that ~wou Id constitute more than fect on the acceptability of a given tech- 10 to 15 percent of the utility’s total nology. I n addition, some technologies may generating capacity. ” In other words, a have environmental side effects that are single plant must be no more than one-half unacceptable no matter what price the uti I i- of the system’s total reserve capacity of 20 ty is willing to pay (e. g., the potential effects to 25 percent. of the addition of large amounts of carbon If a utility could accommodate a first SPS dioxide to the atmosphere). of 5,000 MW, it could accept another pro- LICENSING vided it met a less stringent application of the penetration rule. In other words, the sys- “Licensing . . . is currently the largest single tem would benefit somewhat by redundancy issue facing al I new technologies. ”2° The issues of generating units provided there was a low that will affect the licensing procedure such as probability of both failing at once. siting, health and safety, and environmental As an example, for a utility to accept a concerns must be identified and reckoned with 50,000-MW satellite, it must have a system early in the development of the technology. capacity of 5,000/0.13 = 38,000 MW. This They also have a direct effect on the cost of a exceeds the capacity of any single current technology. utility. Assuming current average rates of Once a generating technology has proven its growth of 3.2 percent for the industry, it commercial feasibility, it generally takes would exceed the capacity of all utilities another 20 years or so for it to be used save TVA in the year 2000. It might, of significantly. The complexity of the tech- course, be possible for a group of several nology, institutional barriers, market growth utilities with the appropriate total capacity (housing, industry, etc. ) market initiative and adequate grid interconnections to take (dispersed v. central use), and system size will on 5,000 MW of power. According to the all have their effects on the rate at which a rule for reserve capacity, for the group to given technology will penetrate the total utili- then assume another 5,000 MW, its total ty market. capacity would have to be large enough for the two satellites together to constitute 20 Engineering Implications of the SPS percent or less of a system capacity of for the Utilities Grid 50,000 MW. The exact percentage any given consortium of utilities would be willing to The SPS would make numerous special —— demands on the utility grids. Some are related ‘ ~ J Donalek and ) L Wtlysong, “lJtillty Interface Re- to the fact that the primary generator or col- quirements for a Soiar Power System, ” Harza Erlglrleerlrlg CO , DOE contract No 31-109-38-4142, report No DO E/E R-0032, Sep- ‘“l bid tember 1978 240 ● Solar Power Satellites

accept would depend on its view of the Short-term variations would be much probability of two SPS units and another more serious. Around the equinoxes, the unit or transmission line failing at the same satel I ite wou Id I ie in the Earth’s shadow for a time (see table 52). short period each night around midnight. As an additional consideration, it should These “eclipses” of the satellite would vary also be noted that supplying 5 GW of re- trom a few seconds duration at the start of serve power from elsewhere in the system the 31-day eclipse period to a fu I I 72 minutes would put a great strain on the dispatching at the equinox and then decrease again to capability of the uti I ity. zero. Because the antenna array wou Id requ i re a warmup period of 15 to 60 minutes, ● Lack of Inertia in SPS Power Generation. — outages at the rectenna would vary from 30 The frequency stability of a utility system is to 140 minutes. Because the eclipses would directly related to the rotating mass or be highly predictable and would occur at mechanical inertia of its collection of midnight in late March and September when generators. It is, in effect, analogous to a loads are often low (typically 40 to 60 per- giant flywheel kept in motion by numerous cent of the peak for summer peaking small driving elements on its rim. Just as a systems), they wou Id be unlikely to con- flywheel adjusts only slowly to a sudden stitute a problem for the system’s reserve removal or addition of individual driving capacity. * However, following the load elements, the utility network takes several swing during the shortest eclipses would seconds to adjust to the loss or gain of place a strain on the ability of the utility to megawatts of power. A generator added to respond because of the need to replace the system adds additional mechanical iner- 5,000 MW very rapidly unless storage were tia as well as power. Because the SPS [n place. reference design wou [d add power but no Without short-term storage, the rate at additional inertia, i.e., it might come on or which SPS power would decrease during an go off line virtually instantaneously, it eclipse would undoubtedly pose control would create surges that would be difficult problems for the grid. As the satellite for the system to accommodate. In order to entered the Earth’s shadow, it would lose use SPS-generated power, the utilities would power at the rate of 20 percent per minute, have to develop new modes of ensuring fre- too fast for the grid to respond. In general, quency stability and control since the pres- the maximum power fluctuation a grid can ent operating mode depends implicitly on accommodate is about 5 percent per min- the mechanical inertia of the system. One ute. However, it would be possible to shut possibility is to add short-term (15 minutes down the satellite at an acceptable rate to 1 hour) battery storage capacity to the somewhat ahead of the eclipse. rectenna. Such an adjustment would add a The satellites and rectennas would require smal I amount to the cost of SPS power. replacement or maintenance of numerous components (klystron amplifiers, solid-state ● Variations in SPS. – Rectenna power output amplifiers, laser components, photocells, wou Id vary seasonal Iy because of the eccen- dipole antennas, etc.) several times a year. tricity of the Earth’s orbit. As currently Normally the outages associated with designed, the SPS would deliver 5,000 MW routine maintenance could be scheduled when the Earth is at maximum distance from during periods of low electricity demand the Sun. At its closest approach during the and are estimated22 to constitute a loss of

northern winter, each rectenna will deliver * I he cfelmands on different utility systems vary regionally about 10 percent more power, or 5,500 MW. Thu\, the truth of this statement must be examined on a reglon- However, because the variation has a year- by-r(~glon basis “ I Grev “Satellite Power System Technical Options and Eco- Iong period, it would be relatively easy to nomics, ‘ OTA working paper, Solar Power Satelllte Assessment, adjust for it continual Iy. 197’4 Ch. 9—institutional Issues . 241

120 hr/yr of SPS power. Assuming mainte- anism for controlling the position of the nance could be scheduled during eclipse beam on the rectenna, which would be ac- periods, the total time the satellite would be complished by a pilot beam directed from unavailable due to maintenance could be the rectenna to the satellite in space. Be- considerably less than this. cause of the finite time of travel in space for Boeing23 has summarized the various an electromagnetic signal, the time between losses of power to which the referenced SPS sensing a position error at the rectenna and might be subject (table 52). Conspicuously correction of it at the rectenna would be missing, however, is the possibility of about 0.2 see, causing an oscillation in satellite equipment failure. It will be of con- power output at a frequency of 5 Hz. Again, siderable interest to everyone concerned to the 5,000 MW nominal output would strain identify as many potential sources of the capabilities of the utility grid to follow unp/anned SPS shutdown as possible. the resultant load variations if short-term Other possible variations in the amount of storage capacity were not made a part of the transmitted power have to do with the mech- SPS system.

● 2“’SPS/Utillty Grid Operations, ” sec 14 of DI 80-25461-3, Boe- Power Reception, Transmission, and Distri- ing Corp bution. –At the rectenna, the power collec-

Table 52.—PotentiaI for Power Variations From the Reference System SPS

Average Average duration of Maximum yearly Frequency of outage per Total power energy Time to Source of power Range occurrence occurrence outage reduction loss maximum Scheduled hrlyr variation percent per year minlyr . GW GW hr power loss Yes No Spacecraft maintenance o-1oo 2 2 X 3,600 120 5 600 6 min x Eclipse ...... 0-1oo 62 3,376 total 56.26 5 281.3 1 min x 71 maximum per/occurrence Eclipse with shutdown and startup...... 5,270 87.8 439 1 min x Wind storm...... 75-1oo 0.01 5,260 87.6 1.25 109.5 5 min x Earthquake...... 90-100 0.01 1,800 30 0.5 15 10 sec x Fire in rectenna system ... . 80-100 0.01 840 14 1 14 30 min x Meteorite hit of spacecraft equipment. 90-100 0.01 1,200 20 0.5 10 100 ms x Rectenna equipment failure ...... 91.5-100 1 50 0.833 0.425 0.35 100 ms x Precipitation ...... 93.3-1oo 50 1 0.833 0.335 0.28 lm x Pointing error...... 94.8-100 5,000 0.6 0.833 0.29 0.24 1s Ionosphere...... 98.5-100 20 10 3.32 0.15 0.24 Is x Ground control ecluir)ment failure . . . . 95-1oo 5 3 0.25 0.25 0.06 0.3 s x Aircraf~ shadow...... 99.99-1oo 20 20 m 0.3 0.0005 0.0015 1s x 1 m maxi occurrence Total without shutdown/startup: 331 hour (3. i’i’Yo) 1,030.8(2.350/~) without shutdown/startup: 362 hour (4.1 20/. ) 1,188.5(2.71 %)

SOURCE: “SPS/Utiiity Grid Operations”, sec 14, D180-25461-3, Boeing Corp. 242 “ Solar Power Satellites

tion system would be divided up into units capacity of the reference SPS less than its of 320 MW or less. The loss of any one or maximum capacity, thereby causing it to be even a combination of several power blocks more expensive. would present few problems for the grid ● Rectenna Siting. — The land requirements for because they would be relatively small com- the SPS reference system are “large (see ch. pared to 5,000 MW. Transmission would be 8). At 350 latitude the rectenna plus its ex- over four to five 500 KV lines or eight 345 clusion area would cover an elliptical area KV lines. The loss of one of the transmission some 174 km2 in extent. By comparison, the lines should not affect the stability of the city of Chicago is 57o km2, and Washington, system or the operation of the SPS. In the D. C., 156 km2. Finding available land far event of decreased load requirements, some enough from population centers and mili- excess power could be absorbed by the tary installations (to make potential electro- rectenna as heat. Sharp drops in power de- magnetic interference slight) and near mand (e. g., an open circuit due, say, to a loss enough to the load centers to make trans- of several transmission lines) might cause mission costs acceptable would not be a overheating of the rectenna diodes if the trivial exercise. Rectenna siting would in- system were unable to dissipate the excess volve the various regulatory agencies and power quickly enough. Hence, protective wou Id have to be addressed by uti I ities very measures would be required. early in the overal I planning process. Maintenance of the dipole antennas and Utilities in far northern latitudes would rectifiers in the rectenna might present a ma- generally find siting more difficult because jor expense for the utility. Although the the necessary rectenna area and rectenna mean time to failure is projected to be 30 exclusion area increases with increasing years,24 this would mean that on the aver- latitude. Some of the most acceptable loca- age, 7 to 8 diodes (in the rectifier circuit) tions are in the Southern and Southwestern could be expected to fail every second, zs United States where terrestrial photovol- leading to an overall failure rate of 3 percent taics and solar thermal devices will also be per year. Increased quality control of the most economic to operate. Offshore siting manufactured components might mitigate wou Id also be possible, though this option some of the replacement needs by decreas- wou Id require extensive study. ing the failure rate. This procedure, though more expensive per unit, might be less ex- The Solid-State Variation pensive than replacing failed components. The sol id-state sandwich appears to be more Operating Capacity Factor. – In order to economical to build and place in orbit in maximize capital investment, the SPS, if de- smaller units (about 1.5 GW),26 mitigating- veloped, should be operated as close to its automatical [y problems arising from the con- “nameplate rating” as possible, i.e., 5,ooO trol of 5 GW of power from the reference MW. However, during periods of very light system I n addition, a smaller rectenna would load (e.g., at night during the spring and fall) make it possible to place the rectenna closer even current baseload nuclear and coal to load centers or in offshore locations. units must sometimes be run at less than fu II capacity in order to follow the load swing. Because it is a microwave system, it would Such factors would make the real operating share the same stability problems that the reference system wou Id experience. “R Andryczyk, P Foldes, j Chestek, and B Kaupang “Solar Power Satelllte Ground Stations, ” IEEE Spectrum, July 1979, Laser System “Satellite Power Systems Utility Impact Study,” EPRI AP-I 548 TPS 79-752, September 1980 J C Bohn, j W Patmore, H W The laser system would present a different Falnlnger ‘5A D Kotin, “Satellite Power System (SPS) State and Local set of challenges and opportunities for the Regulations as Applied to Satellite Power System Microwave — Recelvlng Antenna Faclllties, ” DO E-H CPIR-4024-05, 1978 ) h H a n I ev, op c It Ch. 9—institutional Issues ● 243

utilities. Because it can generate electricity by used to generate electrical energy — or employing infrared radiation to heat a boiler, perhaps, hydrogen. How it might be integrated it could perhaps be used to repower existing into existing uti I ities is unclear. As an electrical coal, oil, or nuclear facilities. A ground-based system, it would require long transmission thermal collector would generate steam that lines leading from the energy parks to the could be used directly to drive a turbine. In ad- point of end use. However, hydrogen gen- dition, the scale of the proposed satellite/ erated at the site could be transported by ground system (100 to 500 MW) would fit exist- vehicles to other destinations. ing utility capacity quite wel 1. For cases where This concept appears to require a national the laser were used for repowering an existing grid in order to make effective use of the large facility, no new transmission lines would be generating capacity of the site (from 10 to 135 needed. GW). Stability would be much less of a prob- On the other hand, several intrinsic Imitat- lem for SOLARE S than for the microwave sys- ions of the proposed laser system would make tem because of the large number of satellites it difficult for the utilities to integrate it into that would reflect sunlight, the inclusion of their grid: storage in the system, and because of the independent blocks of ground-based photovol- ● Weather Limitations. — Although lasers of talcs or solar thermal plants at the site. the overall power and power density of the proposed laser system could burn The SO LARES proposal would be subject to through light cloud cover, heavy clouds similar problems with clouds as the laser con- would make it unusable. Thus, it would be cept. However, the additional radiant energy unsuitable in areas where clouds cover rnlght be great enough to dissipate clouds that the region for more than a few percent of would form in the region. For this reason, large the year. It might be possible to use it in mirrors have also been proposed for weather regions where there are more receiving mod i f I( at ion.27 stations than lasers to support them. Then, if station A were covered by clouds, for Regulatory Implications of SPS28 example, the laser feeding that station could be redirected to station B that was Although this area has received only a cur- under no cloud cover. The resulting extra sory investigation at this time, it is clear that laser radiation at station B could then be the potential for new forms of financial sup- used to generate more electrical power at port and management structures for the SPS that station to compensate for the loss of might engender new regulatory modes. I n gen- power at station A, assuming that B had eral, the SPS is I ikely to lead to greater cen- the necessary extra capacity. This arrange- tralization of the Nation’s utility structure, ment could work wel I for selected parts of leading in turn to a strong need for coordina- the country, i.e., where the likelihood of tion between neighboring Public Utility Com- cloud cover forming simultaneously over missions or perhaps to completely new struc- several stations was smal 1. However, since tures for regulating utilities. cloudy conditions tend to occur over large sections of the Nation at one time, Local v. Regional Control the practicality of this notion would be Utilities have generally entered into a limited. greater degree of cooperation with utilities in other States than have their associated Mirror System regulatory agencies. This state of affairs will A mirror system would be the most highly centralized technology of the four alter- ‘ Va)k, op clt ‘“M Cer$ovltz, “Report on Certain Economic Aspects of the natives. Its proposers envision a few energy SP~ Energy Program, ” OTA Working Paper, SPS Assessment, parks in which the increased daylight would be 1980 244 ● Solar Power Sate//ites

have to change with increasing use of high- siting a rectenna. A single 5,000-MW rectenna capacity generating units and greater grid in- could serve a large population, one which is terconnections. A move toward regional plan- very likely to be distributed across State I ines. ning and control will likely also come about Coordination of regulatory authority could because of the current disparity between come from voluntary interstate agreements or States in siting and other regulations, making it from federally mandated regional planning. more attractive for utilities to build in States The current debate about energy parks where regulations are not as stringent or to would be instructive in identifying and resolv- purchase power from utilities that have a ing some of these issues. Along with this, the surplus of generating capacity. trends toward regional izing economic control In order to regulate their processes, new re- on energy facilities and instituting a national gional regulatory agencies are likely to be set power grid could provide the institutional up long before SPS could be part of the utility framework for addressing siting issues for a grid, leading to greater grid interties. The in- rectenna or SOLARE S energy park. troduction of an SPS would undoubtedly hasten the process because the larger the grid, Rate Structure the more easily outages from a single rectenna The magnitude of the capital investment or a laser receiver could be handled. The that SPS and other future technologies would intermediate-scale sol id-state system would fit require wou Id certainly cause some alteration into this kind of structure easily, but a larger of the utility rate structure. Just what form scale SPS such as the reference system or these alterations might take is currently SOLARES would necessitate an even more unclear because they depend heavily on the widespread system than is now envisioned. form that the SPS companies would take and Although the laser system might be used to how they might be f inanced. repower inter mediate-s i zed generating facilities, the ever present possibility of For example, if the utilities were to own in- massive cloud cover would require system individual SPS plants, they would wish to interties in order to make the most efficient use clude their capital costs during construction of the available laser satellites. (current work in progress) in the current rate base. Most States are presently unwilling to Site Decisions* allow this. However, the extraordinarily high capital costs of other sorts of new generating Siting would be a major issue for each one capacity may make this scheme a necessity. of the alternative technologies and would also (In the other hand, if SPS power were to be require the development of regional coopera- bought directly from an SPS corporation and tion. A major question in SPS siting decisions is sold to the customer, the concern about add- who would have the control; local, State, ing capital costs during construction to the regional, or national entities? Currently, State rate structure would be eliminated for the util- or local regulatory boards make the ultimate ity regulatory agency and shifted to another decisions concerning plant siting. The Nuclear sector of the economy (though they would still Regulatory Commission and the Environmen- be reflected in busbar costs). tal Protection Agency review these decisions. Except for Federal or State land, the planning SPS Corporations and the Utilities. for a 174 km’ rectenna would likely involve several local jurisdictions, one more of whose Currently, the utilities purchase equipment land use regulations may not be compatible and knowhow from competing corporations with an SPS rectenna. However, if the need for who build and service generating equipment. SPS power were great, there might be ade- Because of the scale of investment necessary quate reason to supercede local regulations in to supply the supportive infrastructure for building an SPS, the SPS corporation might *See also chs 8 and 9, pt C wel I evolve as a monopoly, requ i ring Ch. 9—institutional Issues . 245

monopoly-type regulation on the Federal level. of grid-dispatch that we have already dis- Whether generating plants or power are sold, it cussed. is likely that the Federal Government wou Id be ● Reserve Requirements. –The criterion that heavily involved in the regulation of SPS rates any two units (e. g., transmission I ine, gener- and in siting, reliability, and other aspects of ating plant, etc. ) in a utility system must con- integrating the SPS into the utilities’ structure. stitute less than 20 percent of the total sys- Such a state of affairs would be likely to lead tem capacity leads to a minimum size for to a greater degree of centralization of the any single utility system for a given SPS electrical industry whether a national power capacity (see Planning Process). Thus, two grid were instituted or not. 5,000-MW plants could be accommodated by a utility system with total capacity of General Implications for the SPS 33,000 to 50,000 MW or greater. Smaller Centralization v. Decentralization utilities’ systems could accommodate appropriately smaller SPS plants. But in Two opposing forces currently affect the making decisions about whether to proceed utilities industries— a move towards greater with SPS or not, it is important to estimate centralization and an opposite trend towards how much total SPS capacity the U.S. greater decentralization. On the one hand, utilities grid overall could accommodate. economies of scale, shared facilities, and the The projected total capacity of the benefits of regional planning make greater reference system is 300 GW. Could the util- centralization attractive. On the other, the ities grid in 2030 or 2040 accommodate that desire of individuals, communities, and many capacity? companies for a greater degree of energy self- Simply scaling up from the individual util- reliance for economic or social reasons sug- ity or utility grid, using the 20 percent gests that the utilities will have to adjust to an criterion, 300 GW total SPS capacity implies increased demand for grid-integrated dispers- 1,500 CW total electrical capacity in 2030 or 29 ed systems. The utilities are just beginning to 2040, about 2‘A times current capacity. address these issues squarely. Market pres- It is clear that under these stringent condi- sures may make dispersed units increasingly tions, a low electricity demand would pre- more attractive (see ch. 5, Energy in Context) at clude development of SPS from the utilities the same time that the Federal Government point of view. The 20-percent requirement is supports the development of new central tech- certainly overly stringent, since in effect, it nologies. The main issue for the utilities to ad- implicitly assumes that the entire SPS fleet dress is how to accommodate both ends of the wou Id fail at one time (i. e., no reserve power scale in their planning. would be available from other utilities). On the other hand, satellites that would be sub- Market Penetration ject to eclipse (i. e., all those in geostationary From the point of view of the utilities that orbits) would be eclipsed in groups, not sin- would either purchase SPS generated power gly. For a few days around the equinoxes, ap- for distribution in a grid or purchase receiver proximately 18 satellites would be eclipsed installations to incorporate directly into their at once. * Roughly speaking this means that own systems, the ultimate total volume of SPS a band of Earth some 1,250-miles wide in generated power would depend on a number longitude would suffer SPS power outage at of factors in addition to cost. Even if the one time. Thus, there is a distinct limit to the busbar cost of SPS electricity was highly com- amount of lost generating capacity that petitive with other future options, SPS market nearby utilities could supply during the penetration could be limited by reliability eclipse period. Utilities and their regulatory requirements and by the technical difficulties commissions would only be I ikely to in-

“D Morris and J Furber, “Decentralized Photovoltalcs” OTA ‘A ~atelllte placed at each degree of longitude corresponds to Working Paper, SPS Assessment, 1980 15 ~atel I ltes per hour of time 246 ● Solar Power Sate//ites

crease their proportion of SPS beyond the 20 beam-focusing apparatus. In the microwave percent or so of reserve capacity if they design, a pilot beam sent from the rectenna were consistently able to draw power from to the satellite antenna would control the beyond the “shadowed” region, or if the phasing of the beam transmitters. With the March/September night peaks are low loss of the pilot beam, the SPS power beam enough to offset this difficulty. In other would quickly defocus, a safety feature that words, the larger the grid served by SPS the would prevent accidental or intentional smaller the reserve capacity that would be wandering of the beam. The laser beam required in any one region. would be controlled in a similar manner. It For the country as a whole then, a 20-per- would be important to design this apparatus cent penetration for the reference SPS or to be insensitive to minor perturbations in any geostationary SPS must be seen as an operating mode, yet sensitive enough to average limit. Utilities with appropriate maintain its safety qualities. Orientation of backup could accept more. Others, because the reflecting mirrors of the SOLARES sys- of their size, location, or special needs tem would be entirely mechanical and would only accept less than 20 percent. would be controlled by built-in thrusters. Be- A 20-percent penetration of SPS would cause the mirror system would be highly re- constitute 120 GW in the low scenario and dundant, the loss of one mirror would not be about 490 GW in the high one. At a 90-per- catastrophic. It would also be essential to cent capacity factor, the contribution of design the SPS to be as free as possible from electrical energy from SPS would be 3.2 human error. As the nuclear industry real- Quads in the low scenario and 13 Quads in izes, designing a technologically complex the high scenario (44 percent of the total system in which the potential for human er- electrical energy consumed in both cases). ror is small is a difficult and complex task. Here again, experience with operating ● Vu/nerabi/ity. –Another aspect of SPS that systems wculd be essential to utility accept- the utilities would certainly investigate in ance. comparison with other generating options is its vulnerability to hostile actions~” (see ch. System Comparison 7), and to unforeseen technical failure. Of perhaps far more concern to the util- The most acceptable SPS option for the cur- ities would be any vulnerability to technical rent utilities to pursue may be the solid-state or failure (especially common mode failure) or a similarly sized microwave. It would provide to human error. As noted earlier, the utility baseload power with minor weather inter- grid would experience some difficulties in ference at a scale more in keeping with current adjusting to planned outages from the ref- uti I ity practice (i e., 1.5 GW). If future utility erence SPS. Unplanned ones would be far systems develop the capability and the ex- more difficult to adjust for, though they are perience to handle larger increments of gen- a common feature of utility operation. The erating capacity, an SPS similar to the potential for unplanned failure of any of the reference system would be more acceptable, alternative SPS options would only be fully though siting problems might be very great. known if a decision is made to proceed with The laser and mirror concepts, though offer- one option and a full-scale demonstration ing some interesting potential, suffer from were built and tested extensively. severe weather constraints. The possibility that Perhaps the most technically sensitive laser SPS could be used to repower fossil fuel component of the satellite system is the plant~ wou Id make it of particular interest in regions of relatively low cloud cover. One of the significant drawbacks of the mirror con- ‘“P Vajk, “The Military Impllcatlons of Satellite Power Sys- cept is that it wou Id require the utility and tems” NASA/DOE SPS Program Review Meeting, April 1980, Lin- coln, Nebr overal I energy industry to make a radical Ch. 9—institutional Issues . 247

change from its current structure because of associated large energy parks could well slow its very high degree of centralization (10 to 135 its development to beyond 2020. GW per site). This would be particularly true for an SPS system operating in other countries Rate of Implemental ion where the grid system is either nonexistent or The reference system assumes additions of very smalI (see ch. 7, International Issues). 10,000 MW per year to the grid. Assuming elec- Timing of Grid Integration. tricity demand makes feasible 10,000 MW additions to U.S. generating capacity, it is unlike- If SPS followed the pattern of other new Iy that the rate would begin at that high level. energy technologies it would take a long time Again, the utilities would want to have con- to be integrated into the utilities structure. The siderable experience with the first SPS before reference system scenario31 suggests that the they would be willing to invest in additional first SPS could be deliverig power to the grid units. Thus, it is more likely that the annual in about 20 years time. But nuclear power, rate of implementation would begin at less which has been used for generating steam for than 5,000 MW on the average and build to 30 years, and became an active option for the higher levels as utilities gain experience and utilities in 1960 still constitutes only 9 percent (onfidence in SPS. of the country’s total capacity (54,000 MW). * Planning for SPS In the face of this past experience, it seems more Iikely that the demonstration and testing Acceptance of SPS by the utilities would de- phases of the SPS would be longer and there- pend on a number of factors, not the least of fore involve higher costs than can presently be which would be utility involvement in planning envisioned. The utilities are faced with pro- for SPS. But for the utilities to invest their time viding reliable power to their customers. Look- and money in such an effort, they would have ing at SPS from a utilities standpoint, it seems to be convinced that it is worth their while. highly unlikely that the first SPS would be part Thus, SPS must be considered to be economi- of the utility grid before 2010. calIy, environmentally, and socially acceptable compared with the other future energy This estimate is based on technology similar options. Much depends on a comparative to the reference system technology. Develop- analysis of the available options. And because ing a laser SPS might take considerably longer comparative assessment is necessarily a proc- because we simply have less experience with ess carried out over many years, the utilities high-powered lasers. The SOLARES system must Involve themselves in all phases of that would be technically easier to build, but the in- process. A comparative assessment done to- stitutional and political barriers to creating the day, though instructive, is as a snapshot compared to a motion picture. As we know more about each technology in the comparative ““Satellite Power System Concept Development and Evalua- group, the particular parameters will change, tion Program Reference System Report, ” op clt * Nuclear power actual Iy produce~ 13 percent of the electricity leading to a reassessment of the desirability of sold each technology.

ISSUES ARISING IN THE PUBLIC ARENA

SPS Debate miIitary issues surrounding new technologies, The supersonic transport, nuclear powerplants, Public involvement in the development of PAVE PAWS radar facilities and high-voltage technologies has grown significantly in the last transmission Iines are examples of technol- two decades. Debate has focused on the en- ogies that have been subject to recent public vironmental. health and safety. economic and controlversy. Since SPS wouId probably be a 248 ● Solar Power Satellites

federally funded technology (at least in the particular, as important means in overcoming research, development, and demonstration — terrestrial energy and resource limits.33 To the RD&D phases) with long-term and widespread L-5 Society, which has been the most vocal SPS ramifications, public input in the development lobbyist, the satellite system is “a stepping process is crucial, especially in the early stone to the stars, ”34 an important milestone stages. Moreover, the potential effectiveness towards the society’s goal, the colonization of of public resistance to technological systems, space Groups Iike the Aerospace Industries and the public’s interest in direct participation Association of America35 and the SUN SAT makes public understanding and approval im- Energy Council, a nonprofit corporation perative for the development of SPS. established to explore the SPS concept,36 37 believe that SPS is one of the most promising The assessment of likely public attitudes options available for meeting future global towards SPS is difficult, however, because SPS energy needs in an environmentally and social- is a future technology. At present, public Iy acceptable manner. Professional organiza- awareness of SPS, while growing, is minimal. tions such as the American Institute of Even if opinions about SPS were well-formed 38 Aeronautics and Astronautics and the in- today, it is likely that these attitudes would 39 stitute of EIectrical and EIectronics Engineers change with time. Public thinking could be in- support continued evaluation of the concept. fluenced by the other energy and space technologies, perceived future energy demand and Opponents of SPS characteristically support general economic and political conditions.32 terrestrial solar and “appropriate” tech- The state of SPS technology and estimated SPS nologies and are often concerned about envi- costs couId also be important determinants. In ronmental issues. The Solar Lobby40 41 and the addition, the degree of public participation in Environmental Policy Center,42 for example, the SPS decisionmaking process could play a fear that an SPS program would drain re- part in future opinions about the satellite. sources and momentum from small-scale,

Most public discussion on SPS has been con- — ‘‘Iblcf fined to a small number of public interest and “C Hen$on, A Harlan, and T Bennett, “Concern$ of the L-5 professional organizations. OTA has drawn Society About SPS, ” The Final Proceedings oi the ~olar Power heavily on the views of these groups because %te//lte Pro~ram Review, Apr ,22-25, 1980, DOE, Cent-800491, jUIV 1980 p 542 they represent selected constituencies that ‘ 5 Aerospace Industries A$soclatlon, Statement submitted for couId play a key role in influencing future the record In So/ar Power ‘5ate//lte, hearings before the Subcom- public thinking and motivating public action. m Ittee on 5pace Sc Ience and Appl lcatlon~, U S House of Repre- sentatlve~, Mar 28-30, 1979, pp 241-242 While OTA cannot determine whether or not ‘“P (; Iclwr, “Solar Power Satelllte Development – The Next the public would ultimately accept SPS, these Steps, Apr 14, 1978, In So/ar Power Sate//lte, hearings before the interest groups can help identify the issues and Sub( omrnlttee on Space Science and Appl lcatlon~, U S House ot Reprewntdtlves, Apr 12-14, 1978, No 68, pp 165-178 philosophical debates that may arise in the 1‘I Freeman (ed ) Space .So/ar Power f3u//etln, VOI 1, No 1 and future. 2, SLJNSA T [ nergy Council, 1980 ‘“ So/,?r Power ‘$ate//ltes, AlAA Posltlon Paper, Nov 29, 1978, prepared by the AlAA Technical Committee on Aerospace Power Interest Groups Svstem\, ,]nd the AlAA Technical Committee on Space Systems ‘<’H Brown, “Statement on ‘Solar Power Satellite Research, A small number of public interest and pro- Development, and Evaluation Program Act of 1979,’” In So/ar fessional organizations have expressed their P~jwer ‘i.~re//lres, hearings before the Subcommittee on Space views on SPS. In general, many of the indi- S( Ience dnd Appllcatlons, U S House of Representatives, Mar 28- W, 1979, No 15, pp 4-8 viduals and groups that support the develop- “’(’l tlzen \ Energy Project, Solar Power Satelllte$ News Up- ment of SPS also advocate a vigorous space d’]te, Solar Power Satellite Fact Sheet, Coal ltlon Against Satelllte program. SPS proponents, represented by orga- Power \y\tems Statement (newsletters), 1980 “~ [)(>[ O$S, ‘ Solar Power Satellite, ” Sun T/me\, July 1979, pp nizations like the OMNI Foundation, view the 4.5 exploitation of space in general, and SPS in “G C)e Loss, testimony In $o/ar Power Sate//lte, hearings before the Subcommittee on Space Science and Appllcatlons, “Solar Power Satellite Public (lplnlon l~>ue~ Workshop, A U S House of Representatives, Mar 28-30, 1979, No 15, pp Summary, Feb 21-22, 1980, Office of Technology Assessment 109-114 Ch. 9—Institutional issues ● 249

ground-based, renewable technologies. They noted that in most of the discussion, it is argue that compared to the terrestrial solar op- assumed that SPS would be a U.S. project (at tions, SPS is inordinately large, expensive, cen- least in the near term). If the question of SPS tralized, and complex and that it poses greater were posed in an international context, it is environmental and military risks. The Citizen’s possible that the flavor of the following Energy Project has been the most active lob- arguments wouId be altered considerably. Cur- byist against funding SPS and has coordinated rently, public discussion is focused on the the Coalition Against Satellite Power Systems, question of R&D funding. It is anticipated that a network of solar and environmental orga- as public awareness grows, the environmental, nizations. 43 Objections to SPS also have been health, safety, and cost issues will receive raised by individuals in the professional more public attention. Questions of centraliza- astronomy and space science communities tion, military implications and the exploitation that see SPS as a threat to the funding and of space could also be important. practice of their respective disciplines.44 45 While there is a wide spectrum of support for R&D PROGRAMS SPS in the advocates’ community, ranging The primary purpose of an SPS R&D pro- from cautious support of continued research gram in the near term would be to keep the to great optimism about the concept viability SPS option open. However, opponents argue and deployment, almost all opponents object that it makes little sense to investigate this to Government funding of SPS research, devel- complex, high risk technology when other opment, and deployment. more viable alternatives exist to meet our future energy needs.47 In particular, they fear If the SPS debate continues in the future, it that SPS would divert funds and valuable is likely that several other kinds of groups human resources from the terrestrial solar would take a stand on SPS.46 For example, anti- technologies, which they perceive as more en- nuclear groups could oppose SPS on many of vironmentalIy benign, versatile, less expensive the same grounds that they object to nuclear to develop, and commercially available sooner power: centralization, lack of public input, than SPS.48 Opponents also argue that a Gov- and fear of radiation, regardless of kind. Anti- ernment R&D program for SPS would fall easy military organizations might also object to SPS prey to bureaucratic inertia, and that no mat- if they foresaw military involvement. It is likely ter what the results of R&D, the program that community groups would form to oppose would continue because the investment and the siting of SPS receivers in their locality if the attendant bureaucracy would be too great to environmental and military uncertainties were stop. 49 Moreover, opponents believe that not adequately resolved or if public participa- political inertia will be generated from the tion in the siting process was not solicited. relatively large amount of money that is Rural communities and farmers in particular presently allocated to organizations with a could also strongly oppose SPS on the grounds vested interest in SPS as compared to those that, like highways and high-voltage power- groups opposed to SPS. In addition, they are Iines, it would intrude on rural life. concerned that studies evaluating SPS for the Issues purpose of making decisions about R&D funding do not compare SPS with decentralized The issues that repeatedly surface in the SPS solar technologies; they argue that without this debate are shown in table 53. It should be kind of analysis, the public would be unwilling to make a commitment to SPS funding.

“Citizen’s Energy Project, op. cit. ““’’Solar Threat to Radioastronomy, ” New Scientist, Nov. 23, 1978, p. 590. “K Bossong and S. Denman, “A Critique of Solar Power Satel- “sPeter Boyce, Executive Officer of the American Astronomi- lite Technology, “ INSIGHT, March 1980 cal Society, prwate communication 48Cltlzen’s Energy Pro}ect, op. cit “’Solar Power Satellite: Pubiic Opinion Issues Workshop, A “Solar Power Satellite: Public Opinion Issues Workshop, A Summary, Feb. 21-22,1980, Office of Technology Assessment ‘$urrtrriary, Feb 21-22, 1980, Office of Technology Assessment

83-316 0 - 81 - 17 250 ● Solar Power Satellites

Table 53.—Major Issues Arising in SPS Debate*

Pro Con R&D funding ● SPS is a promising energy option ● SPS is a very high-risk, unattractive technology ● The Nation should keep as many energy options open ● Other more viable and preferable energy options exist as possible to meet our future energy demand Ž An SPS R&D program is the only means of evaluating ● SPS would drain resources from other programs, the merit of SPS relative to other energy technologies especially terrestrial solar technologies and the space sciences ● SPS R&D will yield spinoffs to ether programs ● No matter what the result of R&D, bureaucratic inertia will carry Government programs too far cost ● SPS is likely to be cost competitive in the energy ● SPS is unlikely to be cost competitive without Govern- market ment subsidy ● Cost to taxpayer is for R&D only and accounts for small ● Like the nuclear industry, SPS would probably require portion of total cost; private sector and/or other nations ongoing Government commitment will invest in production and maintenance ● Projected cost are probably underestimated considerably ● SPS will produce economic spinoffs Ž The amount of energy supplied by SPS does not justify the cost. Environment, heath, and safety ● SPS is potentially less harsh on the environment than Ž SPS risks to humans and the environment are poten- other energy technologies, especially coal tially greater than those associated with terrestrial solar technologies . Major concerns include: health hazards of power transmission and high-voltage transmission lines, land-use, electromagnetic interference, upper atmosphere effects, and— ‘(sky lab syndrome” Space ● Space is the optimum place to harvest sunlight and ● SPS is an aerospace boondoggie; There are better other resources routes to space industrialization and exploration than SPS ● SPS could be an important component or focus for a ● SPS is an energy system and should not be justified on space program the basis of its applicability to space projects ● SPS could lay the ground work for space industrialization and/or colonization ● SPS would produce spinoffs from R&D and hardware to other space and terrestrial programs International considerations ● One of the most attractive characteristics of SPS is its ● SPS could represent a form of U.S. and industrial na- potential for international cooperation and ownership tions’ “energy imperialism,“ it is not suitable for LDCs ● SPS can contribute significantly to the global energy ● Ownership of SPS by multinational corporations would supply centralize power ● SPS is one of few options for Europe and Japan and is well suited to meet the energy and resource needs of developing nations ● An international SPS would reduce concerns about adverse military implications Military Implications ● The vulnerability of SPS is comparable to other energy . Spinoffs to the military from R&D and hardware would systems be significant and undesirable ● SPS has poor weapons potential . Vulnerability and weapons potential are of concern ● As a civilian program, SPS would create few military spinoffs Ch. 9—institutional Issues ● 251

Table 53.—Major Issues Arising in SPS Debate* —Continued

Pro Con Centralization and scale ● Future energy needs include large as well as small- • SPS would augment and necessitate a centralized in- scale supply technologies; urban centers and industry frastructure and reduce local control, ownership, and especially cannot be powered by small-scale systems participation in decisionmaking alone ● SPS would fit easily into an already centralized grid ● The incremental risk of investing in SPS development is unacceptably high Future energy demand . Future electricity demand will be much higher than . Future electricity demand could be comparable or only today slightly higher than today with conservation . High energy consumption is required for economic ● The standard of living can be maintained with a lower growth rate of energy consumption ● SPS as one of a number of future electricity sources ● There is little need for SPS; future demand can be met can contribute significant y to energy needs easily by existing technologies and conservation ● Even if domestic demand for SPS is low, there is a • By investing in SPS development, we are guaranteeing global need for SPS high energy consumption, because the costs of development would be so great ———. aArguments mainly focus on the SPS reference system. SOURCE: Office of Technology Assessment.

Advocates, on the other hand, view SPS as a spond to claims of bureaucratic inertia by potentially viable and preferable technology. so citing several cases in which large projects, They argue that an R&D program is the only such as the SST and the Safeguard ABM sys- means of evaluating SPS vis-a-vis other energy tem, were halted in spite of the large invest- technologies. Moreover, if the Nation can af- ment. 54 They argue that at the funding levels ford to spend up to $1 billion per year on a currently discussed for R&D, the risk of pro- high-risk technology like fusion, it could cer- gram runaway is very low. tainly afford SPS research that would be much 51 less expensive. proponents maintain that SPS COST research will yield many spinoffs to other Economic issues have played center stage in technologies and research programs whether the SPS debate. Almost every journal account or not SPS is ever deployed. 52 53 They also re- of SPS (particularly those critical of the satellite) has highlighted its cost.55 56 57 The

‘“P. Glaser, “Solar Power From Satellites, ” Physics Today, Feb- ruary 1977, “Solar Power Satellite: Public Opinion Issues Workshop, A “Solar Power Satellite: Public Opinion Issues Workshop, A Summary, Feb. 21-22, 1980, Office of Technology Assessment summary, Feb. 21-22, 1980, Office of Technology Assessment. 52P Glaser, “Development of the Satellite Solar Power Sta- “J Marinelli, “The Edsel of The Solar Age,” Environrnenta/Ac- tion, ” in So/ar Power from Sate//ites, hearings before the Sub- tion, July/August 1979, committee on Aerospace Technology and National Needs, U S “R Brownstein, “A $1,000,000,000 Energy Boondoggle; Sci- Senate, Jan 19,21,1976, pp 8-35 ence Fiction Buffs Will Love It, ” Critica/ Mass )ourna/, June 1980. ‘IT A Heppenheimer, Co/onies in Space (City, State: stack- “L Torrey, “A Trap to Harness the Sun,” New scientist, J UIY pole Books, 1977) 10, 1980 252 ● Solar Power Satellites

predominant questions revolve around R&D cantly increase as SPS is developed. Further- priorities and capital and opportunity costs. In more, the U.S. taxpayers would be required to addition, the calculation of costs themselves support this increase and to maintain an ongo- and cost comparisons between technologies ing commitment to SPS above and beyond the could be subject to extensive scrutiny and RD&D costs, just as they have for the nuclear debate. industry. ” The National Taxpayers Union, in particular, sees SPS as a “giant boondoggle Proponents argue that the only cost open for that will allow the aerospace industry to feed public discussion is the cost of RD&D to the its voracious appetite from the federal taxpayer. 5859 The bulk of the SPS investment trough.”68 Opponents argue that SPS would would be carried on by the private sector in not alleviate unemployment substantially competition with other inexhaustible energy because it provides unsustainable jobs to the alternatives. Furthermore, much of the RD&D aerospace sector alone.69 Most opponents also cost could be returned from other space pro- do not believe that SPS will be cost com- grams such as nonterrestrial mining and in- petitive and argue that the amount of energy dustrialization that build upon the SPS techno- produced by SPS would not justify its large in- logical base. ’” Advocates also contend that an vestment cost. 70 SPS program would produce economic spinoffs by providing domestic employment and The most critical issue for opponents is the by stimulating technological . innovation for question of opportunity cost, i.e., the cost of terrestrial industry.61 Some proponents also not allocating resources for other uses.71 They argue that as an international system, SPS argue that a commitment to SPS R&D would could lead to the expansion of world energy jeopardize rather than stimulate the develop- and space markets. 62 63 In addition, in a global ment of other energy technologies. Opponents scenario, the United States would bear a small- also argue that SPS might foreclose oppor- er portion of the development costs. Finally, tunities for alternate land use, Federal non- advocates believe that in spite of the large in- energy R&D funding, allocation of radio fre- vestment costs, SPS would be economically quencies and orbital slots, resource uses and competitive with other energy technol- jobs. ogies. 64 65 ENVIRONMENT, HEALTH, AND SAFETY Opponents argue that the present cost esti- Opponents contend that the environmental mates are unrealistically Iow.66 They expect risks and uncertainties of SPS far exceed those that like other aerospace projects and the 72 of the terrestrial solar options. They are most Alaskan pipeline, the cost of SPS would signifi- concerned about the effects of microwaves on

5’Solar Power Sate//ite: Pub/ic Opinion /ssues Workshop, A human health, airborne biota and communica- Summary, Feb. 21-22, 1980, Office of Technology Assessment. tions systems. Critics of SPS also argue that it “K Heiss, testimony in So/ar Power Sate//ite, hearings before would severely strain U.S. supplies of certain the Subcommittee on Space Science and Applications, U S materials, thereby increasing our reliance on House of Representatives, Mar 28-30, 1979, pp 132-158 ‘“G. Driggers, letter and statement submitted for the record In foreign sources. 73 In addition, opponents ques- So/ar Power Sate//ite, hearings before the Subcommittee on Space Science and Applications, U S House of Representatives, — pp 407-416 “Solar Power Sate//ite: Pub/fc Opinion Issues Workshop, A “Glaser, “Solar Power Satellite Development–The Next Summary, Feb 21-22, 1980, Office of Technology Assessment Steps,” op clt “J Creenbaum, National Taxpayers Union, letter to the ‘2 So/ar Power Sate//ite: Pub/ic Opinion Issues Workshop, A Senate Energy and Natural Resources Committee, expressing Summary, Feb. 21-22, 1980, Office of Technology Assessment views on H R 12505, July 7, 1978 “Heppenheimer, op. cit “Richard Grossman, Envlronmentallsts for Full Employment, “P. Glaser, “The Earth Benefits of Solar Power Satellites, ” private communication, July 25, 1979 Space Solar Power Review, VOI 1, No 1 &2, 1980 7“Bos\ong and Denman, op clt 5 ‘ R. W Taylor, testimony in So/ar Power From Sate//ites, pp 7 ’ 50/ar Power Sate//ite Pub//c Opinion Issues Workshop, A 48-51. Summary, Feb 21-22, 1980, Office of Technology Assessment “K, Bossong, S, Denman, So/ar Power Sate//ites or How to 7’Citizen’s Energy Project, op clt Make So/ar Energy Centralized, Expensive and Environmenta//y “] Hooper, Star Gazer’s A/ert, update to “Pie In the Sky” Unsound, report No. 40, Citizens Energy Project, June 1979 (newsletter), The Wilderness Society Ch.. 9—institutional Issues ● 253

tion putting Earth resources in space where becoming more important. Opponents, on the they cannot be recycled or retrieved. ” Oppo- other hand, contend that environmental con- nents also cite the large amount of land cerns will remain predominant and that the needed for receiver siting, high-voltage trans- public perception of environmental risks will mission lines, the effects of launches on air uItimately dictate costs. and noise quality, the potential for unplanned Historically, public involvement in techno- reentry of LEO satellites (“Skylab Syndrome”), logical controversies has often been spurred reflected sunlight from the satellites and by concerns about the environmental risks. En- potential adverse effects on climate and ozone vironmental issues couId be very important in as serious problems. 75 future public thinking about SPS as well.82 It is Advocates, on the other hand, maintain that also Iikely that SPS would serve to bring con- compared to other baseload or large-scale troversies over the impacts of other technol- energy technologies, SPS would incur less en- ogies to the forefront, most notably the bio- vironmental risk. 76 77 78 In particular, its effects of microwaves and high voltage trans- climatic effects would be far less severe than mission Iines (60 cycle). While the public might those of fossil fuels and its bioeffects would be concerned about all environmental impacts probably be much less hazardous than those (see table 28), those that most immediately af- of coal and nuclear. Proponents claim that the fect people’s health and well-being would principal advantage of SPS as opposed to ter- dominate discussion. Moreover, environmen- restrial solar and hydroelectric is that it would tal issues would be most focused and ueless land per unit energy.79 Most advocates amplified at the siting stages of SPS devel- are confident that while electromagnetic inter- opment (see Siting section). Public acceptance ference and some atmospheric effects could of SPS wilI depend strongly on the state of be a problem, acceptable methods can be knowledge and general understanding of en- found to mitigate most of the environmental vironmental hazards. It will also depend on the impacts of SPS. Some proponents also argue institutional management of the knowledge; that one of the major benefits of SPS is that it who determines the extent and acceptability transports to space many of the environmental of the public risk may be just as important as impacts typicalIy associated with the genera- the data itself. tion of power on Earth.80 Moreover, air and The most critical environmental issue for the water pollution and resource strains could be reference system at present is the biological ef- alleviated if the Nation mined the Moon or fect of microwaves, not only because the un- asteroids. Some advocates have also stressed certainties are so great, but also because of the the importance of weighing environmental existing controversy over microwave bioef- concerns against the needs for inexpensive fects in general. As the proliferation of micro- energy.81 A few contend that while environ- wave and radio frequency devices has in- mental issues have ranked high in the public creased dramatically, this issue has received mind, convenience and the cost of energy are considerable attention in the public arena. A great many newspaper and journal articles,83 “DeLoss, “Solar Power Satellite, ” op clt as well as television segments on 60 minutes 75 Solar Power Satellite: Public Opinion Issues Workshop, A and 20/20,84 and Paul Brodeur’s book, The Zap- Summary, Feb 21-22, 1980, Office of Technology Assessment “C laser, “Solar Power Satellite Development–The Next ping of America: Microwaves, Their Deadly Steps,” op clt Risk and the Cover-Up85 signal growing public zTHeppenhelmer, oP. c ‘ t “G. O’Nelll, The High Frontier: Human Co/onies in Space (New York William Morrow & Co , Inc , 1977) “lbld 7’Glaser, “The Earth Benefits of Solar Power Satellites, ” op “S Schlefelbeln, “The Invlslble Threat, ” Saturday Review, cit. Sept 15, 1979, pp 16-20 ‘“C W Driggers, “SPS Significant Promise Seen, ” The Energy 84A Bachrach, Satellite Power System [SPS] Public Acceptance, Consumer, September 1980, pp 39-40 October 1978 “Solar Power Satellite: Public Opinion Issues Workshop, A “Paul Brodeur, The Zapping of America (New York W W Nor- Summary, Feb. 21-22, 1980, Off Ice of Technology Assessment ton & Co Inc , 1977)

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concern over the increase of “electronic (NRDC) claims that the NIOSH criteria docu- smog. ” ment that will form the basis of the NIOSH standard, fails to provide a scientifically and The press has been particularly suspicious of medically sound standard; while it admits the the motives and conclusions of the apparently existence of many low-level effects, it pro- small, closed community of microwave re- poses a thermal standard and fails to ade- searchers and decisionmakers in the 1950’s and quately address low-level non-thermal ef- 1960’s. Suggestions of vested interests, con- fects.89 NRDC argues that the proposed stand- spiracy, and coverups stem from the confiden- ard was arbitrarily chosen, just like its tial classification of microwave research by predecessor. NRDC recommends that the radio frequency users such as the military and criteria document be recommissioned, that a the microwave device industry and the lack of balanced team of experts work with NIOSH attempts to solicit public input.86 Whether or and another review the document and that a not such motives in fact existed, the public and temporary emergency standard of 1 mW/cm2 press, fearful of the word “radiation,” have ex- for 10 MHz to 300 GHz, be promulgated. pressed little confidence in “official” claims that microwaves are as safe as they are pur- In spite of the proliferation of microwave ported to be. ovens, public resistance to the siting of technologies that use the radio frequency por- The political edge of the scientific con- tion of the electromagnetic spectrum has been troversy has also been sharpened by several in- strong and often effective. Local residents cidents over a 10-year period of microwave ir- have opposed the construction of broad- radiation of the U.S. embassy in Moscow. The casting towers and radar installations, as well peak power of the modulated field was 18 as high voltage transmission Iines (ELF radia- microwatt, far below the U.S. guideline.87 tion). (See Siting section.) Although neither electronic jamming or surveillance seemed to be the purpose of the SPACE waves, there was concern about attempted behavior control and health hazards that led SPS would represent a giant leap in our pres- to Project Pandora and other studies. These in- ent commitment to space. To some, this space vestigations tended to conclude that the em- component and its supporting infrastructure bassy workers did not encounter health haz- wouId be an unnecessary and expensive com- 90 ards traceable to their exposures.88 Few follow- mitment, while others enthusiastically em- up studies have been conducted however, and brace SPS as the first step towards an extrater- 91 suspicions still exist. Public opinion seems to restrial future for human kind. Others argue have been influenced by the extensive publici- that a commitment to space is desirable, but ty these episodes have received. Articles ques- that SPS would be the wrong route to get there. tioning the ethics and motives of the State It is likely that the discussion of the SPS con- Department leave the reader feeling that the cept would precipitate extensive debate over issues were never adequately resolved. national priorities, domestic space policy and the international and military implications of Most recently the proposed American Na- space. tional Standards Institute and National institute of Occupational Safety and Health Proponents of SPS argue that space is the 92 (NIOSH) microwave standards have been criti- optimum place to harvest sunlight and other cized. The Natural Resources Defense Council resources that are needed for an Earth plagued by overpopulation, resource limitations, and a threatened environment. Many envision a ‘bIbid. 87 Schiefelbein, op. cit. “’Lou I~ Slesln, letter to Dr Anthony Robbins, NIOSH, from 88A. Lilienfeld, et al , Foreign Service Hea/th Status of Foreign NRDC, j Uiy 11, 1979 Service and Other Employees From Selected Eastern European 9(’ Cltlzen’s Energy Project, op clt Posts Fina/ Report, Department of Epldemlology, the John 9’Henson, Harlan, Bennett, op clt Hopkins University, July 31,1978 92 Brownsteln, op clt Ch. 9—Institutional issues . 255

future in which the U.S. mines, industrializes space. A growing public interest in space and colonizes space as a hedge against these utilization or exploration and increased ap- limits to growth.93 94 95 SPS is one step in this vi- preciation of the pragmatic benefits of space sion, for it not only would deliver energy to could put SPS in a favorable light.102 Equitable Earth but would also spur the development of international agreements about the use of hardware, management, expertise and energy space could also spur support for SPS. On the for use by other space activities. In fact, some other hand, ambiguous space agreements, in- proponents have suggested that without SPS, ternational conflicts, or the escalation of the space program will atrophy;96 that SPS space weaponry couId turn public opinion would give NASA a clear context in which to away from SPS. Negative public thinking plan other space projects. Some advocates see about space activities and SPS could also stem SPS, like Apollo, as a way to restore the fron- from the technical failure of a major space tier spirit by dispelling the gloom associated vehicle or satelIite. with limits to growth.97 98 INTERNATIONAL CONSIDERATIONS Many opponents, on the other hand, call SPS Beyond its immediate implications as a an aerospace boondoggle. ” They argue that space system, there are other international SPS, as an energy system, should not be justi- issues associated with SPS. The satelIite system fied on the basis of its applicability to other is seen as a possible focus for either global space pro jets. Moreover, it is argued that it is cooperation or global conflict by advocates not necessary to go to space in order to gener- and opponents alike. ’03 However, opponents ate technological spinoffs; the Nation can en- are especially skeptical of the feasibility of a courage technological competence and inno- muItinational system; they doubt that interna- vation in more direct and less expensive tional cooperation would occur until most of ways. 100 Some critics of SPS also argue that the existing conflicts on Earth are resolved. SPS would serve to escalate and accelerate SPS opponents are most concerned that SPS confrontations in space. would represent U.S. “energy imperialism” by In the future, public opinion about space dominating the cultural and technical develop- and SPS in particular will be influenced by the ment of lesser developed countries (LDCs).104 relative status of space programs in this and Reliance on the industrial nations would im- other countries.101 For example, the pursuit of pinge on third world attempts at energy in- SPS programs in other nations might act as an dependence. Furthermore they argue that SPS impetus for the United States to participate in wouId do Iittle to alleviate the near term or develop its own SPS. In light of the ex- energy needs of LDCs, whereas most terrestrial perience with Skylab, it is clear that the suc- solar technologies could. Opponents also fear cess or failure of U.S. space projects such as that control of SPS by multinational corpora- the space shuttle will have a marked effect on tions would accelerate the movement of eco- public thinking. Grassroots organizations sup- nomic and political power away from individ- portive of space, and the popularity of science uals and communities.105 fiction and space-oriented entertainment, The characteristic of SPS that is most at- could also play a role in determining attitudes tractive to some proponents, on the other toward the exploitation and exploration of hand, is the potential for multinational cooperation. 106 107 In fact, a few contend that “Glaser, “Development of the Satellite Solar Power Station, ” op cit ‘“l bid c t 94tieppenhreimer, oP ‘ ‘)’1 bid 950’ Neill, op. cit ‘)41 bid 9’Peter Glaser, private communication ‘(’5 Bossong and Denman, “A Critique of Solar Power Satellite 97Glaser, “Solar Power Satellite Development–The Next Technology, ” op cit Steps, ” op. cit ‘l’G laser, “The Earth Benefits of Solar Power Satellites, ” op 98 Heppenheimer, oP C’t Clt 99 Greenbaum, op cit ‘“7P C laser, “The Solar Power Satellite Research, Develop- ‘OOOfflce of Technology Assessment, op cit ment and Evaluation Program Act of 1979, ” testimony In So/ar 101 Ibid Power Satellite, 1979, pp 215-224 256 Ž Solar Power Satellites

this is the only feasible arrangement for SPS;108 apparent how the military implications of SPS a multinational SPS would alleviate many of would be viewed. For example, a perceived the problems associated with a unilateral SPS, military potential of SPS and its supporting in- e.g., military implications and high costs. Pro- frastructure might be seen as a real benefit to a ponents also argue that SPS would enhance public concerned about both national security the economies and industrial development of and energy needs. 5 Many might even expect a LDCs by meeting their primary energy needs.109 military presence in space. The laser system They maintain that electricity from SPS could would probably engender more concern over be used to produce methanol, transported to military applications than the microwave or rural areas in labor intensive pipelines for mirror designs. Clearly, future opinion will be heating, cooking, and small industries.110 SPS influenced by the state of space weaponry in might also be used for mariculture to provide this and other nations, future agreements food. SPS advocates maintain that for oil- and about the use of space, and the state of ter- sun-poor Japan and Europe, SPS is one of the restrial weapons as well as arms limitations very few energy options available. Some and the perceived military stature of the also argue that the deployment of SPS would United States relative to the rest of the world. slow the proliferation of nuclear technology in the third world. 2 CENTRALIZATION AND SCALE Debate over future energy strategies often MILITARY IMPLICATIONS involves questions of general social values Military issues are intimately related to rather than a narrow choice of specific tech- space and international considerations. Pro- nologies. One of the issues fundamental to this ponents stress that SPS microwave and mirror debate is that of centralization of energy pro- systems would be ineffective weapons and no duction. The degree of centralization underlies more vulnerable than a terrestrial power- many of the other issues discussed here in- plant. ’ While some believe that a military cluding siting, ownership, public participation, presence in space is unavoidable, it is clear military implications, and the choice between that there are better ways to achieve military terrestrial solar and SPS. competence than with SPS. A primary concern Opponents of large-scale technologies ob- for opponents is that SPS would provide a ject to society’s increasing reliance on com- technological base that would further military plex technologies and centralized infrastruc- capabilities and serve to escalate military con- tures that, they argue, tend to erode the viabili- flicts. 114 Many opponents feel that, like the ty of democratic government by concentrating shuttle, military involvement with SPS is inevi- economic and political power in the hands of a table and that because of its vulnerability, SPS few, and reducing individual and community would accelerate the need for a military control over local decisions.116 Critics of SPS presence in space. Opponents are also con- argue that it would augment and necessitate cerned that because of their highly centralized centralization by requiring a massive financial- nature, SPS satellites and receiving stations management pyramid.117 Utility, energy, and would be targets for attack from terrorists and space companies and Federal agencies would hostile nations. combine into a simple conglomerate, in which [t is likely that the military issue will be of small business would play little or no part. great concern to the public, although it is not They reason that decisions about local energy

‘08 Glaser, private communication, op clt development, receiver and transmission line ‘09 Heppenheimer, op cit siting and economic and environmental plan- ““D Criswell, P. Glaser, R Mayur, B O’Leary, G O’Neill, and ning would necessarily be made by Federal J Vajk, “The Role of Space Technology in the Developing Coun- tries,” Space So/ar Power Review, VOI 1, No 1 & 2, 1980 1l’Bachrach, op clt 1‘ ‘Ibid 1’2Driggers, op cit ‘“Bossong and Denman, “A Critique of Solar Power Satellite “’Office of Technology Assessment, op clt Technology, ” op cit 1141bld ‘‘ ‘Citizen’s Energy Project, op clt Ch. 9—Institutional Issues Ž 257

and industrial decision makers at a national or In generaI, advocates of large-scale technol- perhaps multinational Ievel.118 Many oppo- ogies Iike SPS maintain that centralized sys- nents argue that decentralized solar technol- tems are more reliable and easier to implement ogies are preferable to SPS because they than dispersed technologies. Centralized employ a wider range of skilIs, encourage par- powerplants also produce environmental im- ticipation of small firms, are more directly ac- pacts that are localized and hence directly af- cessible to the individual consumer and fect fewer people. It is argued that dispersed equitably allocate their negative environmen- power generation does not reduce centralized tal impacts to the same people who receive the decisionmaking; in order to be economic these benefits. In addition, unlike SPS that must be systems will require mass production, stand- built in large units to be economic, terrestrial ardization, and regulation and an extensive solar technologies can flexibly accommodate distribution and service network.124 Central- large or small variations in energy demand. ’ ized technologies, at least, are more conve- Moreover, unlike SPS, they do not require nient from the user’s perspective. Advocates large contiguous land areas, a large initial in- also contend that centralized technologies and vestment, large energy backup units or a na- infrastructures are a better means of ensuring tional utility grid to ensure adequate reliabili- equity among the Nation’s citizens.125 For ex- ty. Dispersed energy technologies are also con- ample, many people, predominantly in the in- sidered more appropriate for lesser developed ner cities, wilI continue to rely on centralized nations because they are better matched to delivery systems because they cannot afford end-use needs, produce relatively small im- the capital costs to do otherwise. pacts on local culture and environment and While the public might not couch the prob- don’t require foreign financing, materials, lem in terms of “centralization, ” it is clear that complex infrastructures or hardware.120 Op- people will be concerned about technologies ponents of SPS also view its scale as a severe and systems that appear to prevent them from detriment from an energy planning perspective directly influencing the conditions of their because the incremental risk of investing in an own Iives.126 Public thinking about SPS will SPS development program would be unaccept- then be determined by the extent of public par- ably high; a case of “too many eggs in one ticipation in the planning and decisionmaking basket.121 process, experience with centralized and Most proponents of SPS argue that the Na- dispersed technologies, attitudes towards tion’s energy future will be characterized by a energy, space, and utility conglomerates as mix of centralized and dispersed energy gener- well as the perceived influence and benefits ating systems, but that only centralized tech- (e g., convenience) of centralized technologies. nologies like SPS will be able to meet the needs of industry, large cities, transportation FUTURE ELECTRICITY DEMAND and fuel production.122 In addition, the cen- Those in favor of SPS tend to foresee an tralized nature of SPS facilitates its adoption energy future characterized by high electricity into the existing electricity infrastructure.123 consumption and an expanded power grid.127 Some organizational centralization may result, Many equate economic well-being to high but this will occur in the utility and aerospace energy growth rates.128 Even if the United sectors, already strongly centralized, and so it States is not able to absorb all of an SPS will not cause a significant new concentration “H Brooks, “Critique of the Concept of Appropriate of power. Technology”, In Appropriate Technology and Social Values — A Cr~tlca/ Appraisa/, F Long and A Oleson (eds ) (Cambridge, ‘ “Office of Technology Assessment, op clt M,iss Balllnger Publlshlng Co , 1980) ‘“DeLoss, testimony in So/ar Power Sate//lte, op clt “Offlc P of Technology Assessment, op clt ““Off ice of Technology Assessment, op cit 2’)1 bid “’DeLoss, “Solar Power Satellite, ” op clt 170fflc e of Technology Assessment, The Energy Context of “’Office of Technology Assessment, op clt SP} Work ~hop, A Summary, September 1980 ‘“R Stobaugh and D Yergin, Energy Future (New York Ran “Off Ice of Technology Assessment, Solar Power Sate//ite dom House, 1979) Public Op/rrlon Issues Workshop, A Summary, Feb 21-22, 1980 258 ● Solar Power Satellites

system, they argue that on a global scale there Siting will always be high demand.129 130 Proponents Historically, public debate over the in- also argue that if SPS is able to provide relatively cheap, environmentally benign and troduction of a technology has been most pro- plentiful energy, then it will be consumed and nounced at the siting stage. It is during the demand will be high. ’3’ Some argue that no siting phase that public opposition to a tech- matter which demand scenario is finally real- nology has been most vocal, organized, and ef- ized, we need to investigate every possible fective. Citizens have taken direct action electricity option today, so that we have ade- against the siting of powerplants, airports, prisons, high-voltage transmission lines and quate choices in the future. military facilities by forming local and na- Most opponents, on the other hand, envision tional groups, publicizing their cause through an energy future dominated by conservation the media, taking legal action, demonstrating, and solar technologies.123 Some believe that and occasionally resorting to civil disobedi- electricity should play a minor role in our ence and violence.137 In general, siting con- energy supply mix because of its thermo- troversies revolve around issues of environ- dynamic inefficiency.133 Furthermore, most op- mental effects, health and safety risks, re- ponents contend that even if electricity de- duced land values and fair compensation, pri- mand were to increase somewhat, it could be vate property rights, opportunity costs, vul- satisfied with existing technologies.134 They nerabiIity to attack, and public participation in argue that by developing large-scale energy land-use decisions.138 It is clear that in the systems such as SPS, we are guaranteeing high absence of national land-use policies, conflicts energy use because the investment in their over land-use priorities will escalate as the development is so great. population grows, and friction between rural Public attitudes about SPS will depend on and urban America and local communities and regional or national decision makers will in- the relative cost and availability of energy, the advancement and proliferation of electrical crease ‘‘9 end-use technologies, attitudes towards energy For SPS, siting is a major issue. * SPS would companies and forecasters of electricity de- be particularly prone to siting difficulties mand, and the sense of energy security as because of its large contiguous land re- determined by domestic supply v. reliance on quirements, its potential military implications, foreign sources. 35 and its use of nonionizing electromagnetic radiation (e. g., microwaves or lasers) in power SPS Technical Options transmission and distribution. This last factor How might future public reaction to alter- is most important because of considerable native SPS systems differ?136 Table 54 iden- uncertainties associated with the environmen- tifies some of the relative benefits and draw- tal and health risks of electromagnetic radia- backs of the proposed SPS systems as they tion as well as possible interference with electromagnetic systems. These uncertainties and might be perceived by the public. -—- — ‘“L ( aldwell, L Hayes, and I MacWhlrtey, Citizem and the / nvtronment Case Stucfles in Popu/ar Act/on (Broom lngton, Ind I ndlana University Press, 1975) ‘2’O’Neill, op cit. ‘ “OftIce of Technology Assessment, op clt ‘30Glaser, private communication, op clt ‘ “lbl(l ‘J IOffice of Technology Assessment, The Energy Context of *It ts assumed that SPS receivers would be sited on land Off- SPS Workshop, Op. clt shore locations are also possible and might alleviate many of the I J21bld ~PS Ian(j-use problems, but are not specifically addressed here ‘“A B Lovins, “Energy Strategy The Road Not Taken?” - Also not considered here are possible multiple land uses If it can Foreign Affairs, October 1976 he shown that land can safely and economically be used for ‘ “Office of Technology Assessment, The Energy Context of iltlng 5 PS receivers and other uses (e g , agriculture, pasture SPS Workshop, op. clt land) simultaneously, then siting on private land might not be a ‘‘sOffIce of Technology Assessment, So/ar Power Sate//ite: problem However, In the absence of detailed assessments on the Pub/ic Opinion /ssues Workshop, op clt ( osts and environmental Impacts of multiple uses, it IS assumed ‘Jblbid I n th IS section that I and IS dedicated to SPS receivers alone Ch. 9—institutional Issues ● 259

Table 54.—Potential Benefits and Drawbacks of SPS Technical Options

Advantages Disadvantages Laser system . Does not use microwaves ● Possible weapon . Of SPS systems, requires less land area per site and ● Health and safety impact of beam wanders can deliver smaller units of energy ● Weather modification Mirror system ● Most environmentally benign of SPS systems ● Largest land requirements per site ● Least weapons potential of all SPS systems ● Illumination of night sky ● Least complex to demonstrate, most immediately ● Weather modification reliable system . May fall out of low-Earth orbit ● Possibly least expensive system Solid state . Can deliver smaller units of power than mirror or • Microwave bioeffects reference system ● Electromagnetic interference ● Land per site is smaller than mirror or reference system . Satellites in GEO (in vulnerable to unplanned reentry) and can be placed over the ocean ● Less weapons potential than lasers . Fairly well-developed technology Reference system ● Satellites in GEO (invulnerable to unplanned reentry) . Microwave bioeffects and can be placed over the ocean • Electromagnetic interference ● Less weapons potential than lasers ● Fairly well-developed technology

SOURCE: Office of Technology Assessment

their institutional management have been over the construction of a powerline through responsible in part for controversies over the 8,000 acres of prime farm land. ’43 After attend- siting of a great many other technologies that ing public hearings and installing solar and utilize the radiowave spectrum. Community re- wind devices in their homes to reduce their de- sistance to the siting of radar installations, pendence on the utilities, some became frus- broadcasting towers, and high-voltage trans- trated with what they perceived as the un- mission lines, for example, has been particular- responsiveness and dishonesty of the utilities ly strong and unexpectedly effective. and finalIy resorted to demonstrations, destroying utiIity towers and equipment. Citizens groups have actively opposed transmission lines in a number of States including The siting controversies most relevant to the Oregon, New Hampshire, lowa, and Mon- SPS microwave systems are the disputes over tana.140 As a result of public action in New the Navy’s Project SEAFARER (Surface ELF* York, the State Public Service Commission has Antenna for Addressing Remotely-Deployed expanded the minimum right-of-way for new Receivers), a 25,600-mi2 underground radio lines and established an Administrative Re- antenna for communication with nuclear sub- search Council to study and assess health marines; and the Air Force’s PAVE PAWS (Preci- risks.”’ The legislatures of a few New York sion Acquisition of Vehicle Entry Phased Array counties have adopted resolutions opposing Warning System), a radar system.’” When the the construction of 765 KV lines. ’42 In Min- Navy attempted to locate SEAFARER at differ- nesota, farmers battled with the public utilities ent times in Wisconsin, Texas, New Mexico, Nevada, and Michigan, it encountered vehe-

140’’ The New Opposition to High-Voltage Lines, ” Business Week, November 1977 14’H Nuwer, “Minnesota Peasant’s Revolt, ” Nation, VOI 227, ‘41A. Marino and R Becker, “H Igh Voltage Lines. Hazard at a Dec 9, 1978 Distance,” Environment, VOI 20, No 9, p 6-15 * E 1 F (extremely low frequency) radio waves ‘“K Davis, “Health and High Voltage, ” Sierra C/Ub 6u//etin, ’44P Flrodeur, The Zapping of America, Their Deadly Risk and JulV 1, August 1978 Cover-[/p (New York W W Norton & Co , 1977) 260 ● Solar Power Satellites

ment local opposition. Residents in these com- cases, communities would prefer to leave a munities were concerned about the health haz- site overgrown than consent to any kind of ards of ELF radiation. Ranchers in Texas were development. For SPS as well as other power- also worried about the effects on livestock. plants, dumps, mines, and military installa- Opponents raised other issues including vul- tions, siting in remote areas could be a dif- nerability to nuclear attack, private property ficult task, especially in parts of the country rights, and decreased land values. 45 Referenda where residents have already mobilized defeated SEAFARER’s construction in several against other large-scale projects.151 According counties in Michigan, and in an unprecedented to another workshop participant, one farmer, action, the Governor of Michigan rejected the when asked about the SPS proposal, re- military program.146 The Governor of Wiscon- sponded, “I’ve had enough. I’m ready to get sin also accused the Navy of suppressing en- my gun out.”152 vironmental impact studies that reported Another factor that emerges from siting con- possible environmental and health hazards.147 troversies is that while concerns over the en- Although the ELF program is still being funded, vironmental and health risks of a technology it has yet to find a new site. are very important to nearby residents, this Legal action has also been taken against the issue may mask related concerns such as un- Air Force’s plans to build PAVE PAWS in Cape sightliness and devaluation of local property Code, Mass., and Yuba City, Calif.148 Fear of vaIues153 that may be more important to the adverse microwave bioeffects, especialIy long- Iocal community. For example, in the Min- term, low-level effects, sit at the heart of the nesota powerline dispute, the fundamental controversy. While the Air Force stressed that issue for many of the farmers was the question health risks were negligible and emphasized of land-use, i.e., farmland v. right-of -way. ’54 the need for national security, local groups However, this issue was channeled into en- argued that the data did not support the claim vironmental and health concerns that had that PAVE PAWS will not jeopardize their greater political leverage in the courts and to health. 149 which the utilities and the general public were more responsive. While the health effects of Several key observations can be made from ELF radiation were the most frequently ar- these disputes. First, farmers, ranchers, and ticulated concern of communities opposing rural Americans are becoming an increasingly SEAFARER, it is clear that to some residents, active social force working against the intru- economics really lay at the heart of the con- sion of urban America on their rural quality of troversy 155 These people were primarily con- life. As one OTA workshop participant familiar cerned that Iand values might decrease if with powerline siting controversies remarked, potential buyers worried about the health ef- “Developers say that high voltage transmission fects, and might not have opposed the siting if lines wouldn’t make any more noise than a they had been justly compensated. Other resi- highway would and the reaction of people is dents were most concerned that the presence ‘What do you mean? –That’s why we’re out of SEAFARER would make their land more here. We don’t want to be near the high- vulnerable to military attack; this would ways’ . . , . (Rural Americans) are sacrificing threaten their safety and could also reduce the the kind of life they are out therefor, for the vaIue of their land.156 energy excesses of urban America.150 In many

‘“c Ellis, “Sanguine/SEAFARE R,” Sierra C/ub Bu//etin, VOI 61, ‘‘I blci No 4, April 1976 ‘)lbld “’Brodeur, op clt 5‘1 bld 147S Schiefelbein, “The Invisible Threat, ” Saturday Review, ‘“1 bld Sept 5,1979, pp 16-20 “$joseph Thlel, Texas State Department of Health, private ‘40 Brodeur, op cit cc]mmunlcatlon, Nov 28, 1979 ‘4’S. Kaufer, “The Air Pollutlon You Can’t See, ” New Times, ‘“P Boffey, “Project SEAFARER Critics Attack National Mar 6,1978 A( ademy s Review Group,” Science, VOI 192, June 18, 1976, pp ““Office of Technology Assessment, op clt 121 )-1 21 -i Ch. 9—institutional Issues ● 261

This second observation also points to the had been more open. Public participation complex interrelationship between environ- should be solicited whenever and wherever mental and health risks, costs, land and air use, possible, ideally even before the siting stage. private property rights, esthetics, and public Too often, residents become frustrated and re- control over local decisions. For SPS, it is clear sentful towards developers and officials who that the choice of transmission frequency and make inadequate and occasionally dishonest’ power distribution as well as public radiation attempts to involve the public in meaningful standards could have a great bearing on the decisionmaking. This practice has led the pub- area of land that would be required as a buffer lic to seek other forums to voice complaints, zone, the number of people potentially af- thereby delaying decisions and driving up fected, compensated, and/or relocated, and costs. SPS developers must be well-informed hence the cost of developing SPS. In addition, about the environmental, economic, and mili- the size of each SPS unit and its location could tary implications of SPS and shouId arrange for determine the extent, number and therefore open dissemination and discussion of that in- cost of transmission lines that would have to formation. In addition, no matter what objec- be sited. The cost of a proposed energy facility tive research findings are, public perceptions such as SPS can also be increased if developers of potential hazards are largely influenced by do not solicit public participation and disputes public confidence (or lack thereof) in “offi- and court battIes delay construction. Siting cial” interpretation of that data (see Environ- should therefore be considered as early as ment, Health, and Safety). Whether justified or possible in the development process; public in- not, the public is considerably more cautious put is an essential element in the development and fearful of the biological effects of and design strategy. microwaves and other electromagnetic radiation than are many representatives of Govern- Finally, it is clear that many of the siting ment and industry. But until the uncertainties disputes might have been resolved earlier and are resolved to the public’s satisfaction, the more easily if the channels of communication past cases strongly suggest that local resist- between developers and the local community ance to SPS receivers could be substantial. APPENDIXES Appendix A ALTERNATIVES TO THE REFERENCE SYSTEM SUBSYSTEMS

Solar-Thermal Power Conversion ators of the space-based thermal powerplant therefore become the key limitation on perform- The basic operational principle involved in solar- ance, and counteract the beneficial effect of thermal-electric power systems is identical to that potentially high-cycle efficiency. The most effec- of virtually al I conventional ground-based power- tive space-based thermal power cycle, then, is gen- plants, with a solar furnace replacing the fuel-fired eralIy the one that minimizes the radiator mass. furnace or nuclear reactor normally used to heat the power-cycle working fluid. The 10-MW dem- The Brayton and Rankine Cycles onstration plant at Barstow, Calif., is such a solar- The two “simple” solar-thermal cycles con- powered thermal cycle. Virtually all components sidered for SPS are the Brayton and Rankine of such power systems have been extensively used cycles—the cycles used on Earth for gas turbines and/or tested on Earth, and hence solar-thermal and steam turbines, respectively. In the Brayton cy- systems for potential space applications in the SPS cle, a compressor compresses a gaseous working time frame would enjoy the availability of a large fluid, that is then heated by solar energy concen- body of applicable technology, hardware, and ex- trated into an “absorber” by large, diaphanous perience. Significant problems are foreseen, how- thin-film solar mirrors having a concentration ratio ever, in reducing the mass and complexity of space- of perhaps 2,000-to-l, then discharges its waste based powerplants to levels that make them com- heat to a radiator. It then returns to the compressor petitive with the reference system photovoltaic and repeats the cycle. power source. The Rankine cycle utilizes the same basic energy The basic rationale for considering thermal source as the Brayton cycle —typically, a 2,000-to-l power cycles is their inherently high energy conver- solar concentrator mirror focused on an absorber sion efficiency. High-performance thermal cycle – but employs a condensable liquid, or, frequently, power generators on Earth routinely attain overall ordinary steam. The solar energy impinging on the efficiencies of more than 40 percent, as compared absorber boils and superheats the steam, which with the 17-percent projected efficiency for the ref- then drives a turbine. The steam then condenses in erence-system photovoltaics, and it is quite prob- the radiator at constant temperature. The condensable that material and component developments ed water is then pumped back up to high pressure during the next decade or two could extend overall and forced into the boiler (absorber) to complete operational thermal-cycle efficiencies for ter- the cycle. restrial units to over 50 percent. Unfortunately, The Brayton and Rankine cycle options were re- however, the space environment is such that these jected for the reference system, despite their efficiency levels, even with advanced-technology relatively high efficiencies, because of the high power-conversion hardware, are extremely difficult radiator mass, the lower projected reliability of to achieve. The fundamental problem is that of rotating machinery, and relative complexity of or- heat rejection; that is, in accordance with the dic- bital assembly operations as compared with the tates of the Second Law of thermodynamics, it is photovoltaic options. However, recent develop- necessary that any heat engine reject to its environments in high-temperature heat exchangers and tur- ment some of the energy it receives (the ubiquitous 1 bines, and particularly innovative designs of heat- “thermal pollution” of Earth-based powerplants). pipe and other radiators2 3 now make Brayton-cycle On Earth, effective heat rejection at the low tem- turbines more attractive. peratures needed for high thermal efficiency is readily accomplished by using vast quantities of “’Review Study of a 13rayton Power System for a Nuclear Electr!c Jpace( raft, j PL contract 955W08, Garrett-AlResearch report No 31- cool water or air. In space, on the other hand, all 1288A ()( t 9, 1979 heat rejection must be accomplished solely by ‘Yale C F astman, “A Study of the Appl Icatlon of Advanced Heat Pipe radiation, a process that depends on the fourth Technology to Radiators for Nuclear Spacecraft, ” Thermacore, Inc , Lan- c a~ter Pa E)ec 1, 1975, a I so see Ya Ie C E astm an, ‘‘Advanced Heat PI pes power of the radiator’s temperature. Hence effi- [n Aero$pace Power System s,’ A IAA paper No 77-501, St I. OUIS, Mo , Mar cient heat rejection in space can be accomplished I -1, 1977 only at high temperatures, which by the Second ‘)ohn Hedgepeth and K Knapp, “Preliminary Investlgatlon of a Dust Radiator tor Space Power System s,” Astro Research Corp report No ARC- Law results in reduced thermal efficiency. The radi- rN 10’14 Mar 1978

265 266 ● Solar Power Satellites

Other Thermal Cycles materials cost less than either of the two selected materials, their efficiencies are low and there is lit- Other thermal cycles have also been con- tle experience in their production. Other factors 4 5 sidered, to be used independently or in con- considered by the National Aeronautics and Space junction with the Brayton or Rankine cycles in Administration before selecting the two reference a combination. The most Iikely prospects are system options were total system mass, materials 6 7 the thermionic and the magnetohydrodynamic availability, susceptibility to radiation damage, 8 (MHD) cycles or the wave-energy exchang- development status, manufacturing processes, and 9 10 11 12 13 er. energy payback. Other potential photovoltaic None of these seems particularly well adapted materials that were rejected due to obvious pro- for use in an independent mode in space, although blems with one or more of the above factors in- any one of them may have potential when used in clude selenium and various selenides, cadmium combination with either the Rankine or Brayton cy- telluride, copper sulfide, gallium phosphide, ir- cle. The primary consideration for these cycles is idium phosphide, and a number of higher order in- the tradeoff between high efficiency and high organic compounds. radiator mass. Principal areas requiring research and/or additional development are in the high- Concentration temperature solar collection and absorption portions of all systems and high-performance heat- Another important parameter is the concentra- rejection devices, as well as extensive testing and tion ratio (CR). The selection of CR = 2 for the pilot operations to establish the required levels of reference-system gallium arsenide option was reliability and reductions in cost uncertainties. strongly Influenced by cell temperature considerations.14 Should cell technology develop that would Photovoltaic Alternatives retain high efficiency at elevated temperatures, higher concentrations might prove cost effective, Alternative Materials since both the mass and the cost of reflector materials are considerably less than those of Alternative photocell materials considered be- photocelIs. fore selecting the reference system options of There is good experimental evidence that the single-crystal silicon and galIium aluminure-ars- gallium aluminum-arsenide/gal lium-arsenide cells enide were amorphous silicon, polycrystalline sili- selected for the SPS could utilize much higher con- con, cadreium suIfide, copper iridium selenide, and centration ratios to gain higher overall efficiency. polycrystalline gallium arsenide. Although all these There has been considerable development in con- ‘Daniel L Gregory, “Alternative Approaches to Space-Based Power centrating photovoltaic subsystems for terrestrial Generation, ” /ourrra/ of Energy 1, March-April 1977, pp 85-92 use during the past 2 years, and it is possible that ‘Wllllam P C Ilbreath and Kenneth W Billman, “A Search for Space Energy Alternatives, ” In “Radlatlon Energy Conversion In Space, ” Prog- passive rather than active cooling may be possible. res~ In Astronaut/c$ & Aeronautics, vo/ 61, Al AA, N Y , ] uly 1978, pp 107-125 ‘G O , Fitzpatrick and E j Brltt, “Thermlonlcs and Its Appllcatlon to Multicolor Photocell Systems the SPS, ” Ibid, pp 211-221 ‘(For example), W Phllllps and J Mondt, “Thermlonlc Energy Conver- Photocells respond to only a part of the avail- sion Technology Development Program, ” Progress report No 630-36 (for able solar spectrum that impinges on them. It is June-September 1978), Jet Propulsion Laboratory, Pasadena, Callf , Nov 15, 1978 possible to achieve more efficient utilization of the ‘C V Lau and R Decher, “MHD Conversion of Solar Energy, ” In solar spectrum by: 1 ) manufacturing a single photo- “Radlatlon Energy Conversion In Space, ” K W Blllman (ed ), Progress In cell from various materials, each responding to a Astronautics & Aeronautics, vo/ 61, Al AA, N Y , July 1978, pp 186-200 15 “Robert T Tausslg, Peter H Rose, John F Zumdleck and Abraham different wavelength band; or 2) using separate Hertz berg, “Energy Exchanger Technology Applied to Laser Heated celIs, each optimized for a different spectral region Engines, ” Ibid, pp 465-478 and using an optical system to split the incident 1(’W E Smith and R C Weatherston, “Studies of a Prototype Wave Superheater Faclllty for Hypersonic Research ‘ report No HF-1056-A-I, light into the corresponding spectral ranges. contract AFOSR-TR-58-I 58, AD207244, Cornel I Aeronautical Laboratory, Buffalo, N Y , December 1958 ‘1 W Iame$, and R L Moon, “CaAs Concentrator Solar Cells, ” Pro- “Abraham Hertzberg and Chan-Veng Lau, ‘A High-Temperature cee(lIrtw 01 /he I T th Photovo/talc Specfa/lsts Conference, 1975, pp Ranklne Binary Cycle for Ground and Space Solar Appllcatlons, ” In 40,? 408 “Radiation Energy Conversion in Space, ” K W Blllman (ed ), Progress In Richard j Stlrn, “Overview of Novel Photovoltaic Conversion Tech- Astronautics & Aeronautics, vo/ 61, Al AA, N Y , July 1978, pp 172-185 niq~i IPS at H Igh I ntenslty Level s,” In “Radlatlon Energy Conversion In “Arthur T Mattlck, “Absorption of Solar Radlatlon by Alkali Vapors, ” ~pal e K W Blllman (ed ), Progress In Astronautics & Aeronautics, VOI Ibid, pp 159-171 fl / I Uly 1978 pp 136-151 ‘ ‘A jay Palmer, “Radlatlvely Sustained (“eslum Plasmas for Solar E lec- ‘‘ I aan, ] url~~on, “Multlcolar Solar Cel I Power System for Space, ’r Ibid, trlc Conversion,” Ibid, pp 201-210 pp 1 5/! 158 Appendix A—Alternatives to the Reference System Subsystems ● 267

Although the technology for both approaches is the vacuum-tube devices. Further, their small known, it is far from having been proved practical, size and potentially low unit cost facilitate con- and will require considerable research and devel- venient research and development activities. opment effort before being considered for future The basic problem with solid-state devices is operational systems. The second approach appears their low-temperature capability, which implies to be the most promising in principle. However, it low power, coupled with their low-voltage out- suffers from a lack of basic data on the photovol- put. Additional potential problem areas are un- taic materials that might be used for it. Despite certain efficiency, current high cost for high-per- their attractiveness from the standpoint of effi- formance units, and a host of as yet unresolved ciency, both systems also require either higher transmission, control, and power distribution mass or concentrator systems, which may require complexities.20 However, these devices are still active cooling. Again, vastly more research is in the early stages of being evaluated for the SPS needed to determine the overall effectiveness of application, and it is Iikely that studies of the ex- these concepts. tent devoted to vacuum-tube devices during the past few years can reduce the present uncertain- Alternative Microwave ties associated with sol id-state power conversion and transmission. Power Converters A major area for concern with the solid-state devices is the paucity of data and experience on I n addition to the klystron, several other devices phase control. Although the same generic type of may be capable of converting satellite electric retrodirective control is projected as for the power to microwaves and transmitting them to reference system, much research, analysis, and Earth. The solid-state amplifier, based on semicon- technology advancement will be needed to ductor technology, could result in a significant and beneficial change of the entire system. The latter define its phase control capabilities to the necessary level of confidence. serves as one of the four systems considered in this assessment. Crossed-Field Amplitier. Thls device in the term Photoklystrons of an “amplitron, ” was originally suggested for the reference system in place of the klystron The photoklystron combines the principles of a (linear beam amplifier). Another form of this de- conventional klystron transmitting tube and the vice, the magnetron, appears to have consider- photoemitter in a single device. Sunlight falling on able merit, * particularly in reducing the spurious a photoemissive surface generates a current of noise and harmonics generation of the electrons oscillating in such a way as to emit radio microwave antenna. I n smaller form (1 kW), this frequency electromagnetic waves. If used on the is the familiar unit that powers microwave ovens. SPS, the resultant microwaves could be beamed to The latter devices are reliable and cheap. Earth by using a resonator waveguide. Whether working devices of the 70-kW capacity Potential advantages of the photoklystron over needed for the reference system antenna will the photovoltaic array/klystron are that it could in- prove to be cost effective and possess the re- crease the useful portion of the photoelectric quired signal characteristics must await design energy spectrum as compared with photovoltaics 21 and testing, individually and in a phased array. (it may reach efficiencies as high as 50 percent as So/id-State Devices. The principal motivation for compared with 15 to 20 percent for conventional considering solid-state devices” is their extremely photovoltaics), and that it would greatly simplify 22 high reliability;17 18 projected failure rates are the entire space segment of the SPS as compared 100 times lower than those of the reference-sys- with the reference system, by (a) eliminating the tem vacuum-tube klystrons or amplitrons.19 A solar celI arrays altogether, (b) eliminating the need secondary advantage of solid-state devices is for on board power distribution, (c) eliminating the their potential for lower mass per unit area than rotary joint and sliprings, (d) reducing the individual klystron power and heat dissipation require- *W C Brown, Microwave Beamed Power Technology Improvement ments (there would now be many more klystrons PT-5613 J PL contract 955-104, May 1980 “G M Hanley et al , “Satelllte Power Systems (SPS) Concept Deflnl- ‘(’lbld tion Study, ” First Performance Review, Rockwell International report No ‘‘C Ibraeth and Blllman, op c[t SSD79-0163, NASA MSFC contract NAS8- 12475, Oct 10, 1979 “}ohn W Freeman, Wllllam B Colson and Sedgwick Slmons, “New ‘nGordon R Woodcock, “SolId-State Microwave Power Transmitter Re Method\ for the Conversion of Solar Energy to R F and Laser Power, ” In view, ” Boeing Aerospace Co DOE SPS Program Review, June 7, 1979 Space ‘danufacturlng 1 I l,’ Jerry Grey and Chrlstlne Krop (eds ) Al AA, ‘Vlbid New York November 1979 268 ● Solar Power Satellites

distributed over a much larger area), thereby in- ated baseload electricity may prove extremely dif- creasing the lifetime of individual klystrons, (e) ficult, it has been suggested that rectennas be reducing individual klystron cost, and (f) reducing located in shallow offshore waters. * The costs of rectenna area requirements, since the transmitting such siting would certainly be higher for a given antenna is much larger than that of the reference area than for comparable land-based sites, but the system. system costs might be cheaper overall because of One suggested system (fig. 10) consists of a large cost reductions in rectenna size. The considerable elliptical array of photoklystrons, constituting the body of relevant experience that was developed for collector and antenna. A large mirror (that could offshore airports would be useful for studying this also be a concentrator) would reflect sunlight to possibility. The land areas that have been con- the photoklystrons. Note that even though the mir- sidered for offshore airports are comparable to the ror and antenna must rotate with respect to each needs of SPS rectennas (e. g., 50 to 20 kmz). other to maintain proper Sun-facing and Earth- It may be possible to reduce the necessary area facing attitudes, as in the SPS reference system, of an offshore rectenna by eliminating most of the there is no need for a mechanical connection be- buffer zone and “flattening” the power distribution tween them; in fact, their relative alinement is not of the beam across the rectenna. Though potential- at all critical. ly costly, the option may be taken very seriously by Small working models of photoklystrons exist, the European community for whom rectenna siting but have not yet demonstrated any of the system on land would prove most difficult. It may also find characteristics needed for a practical and cost- ef- uses along the shores of densely populated areas in fective SPS. Hence the concept still remains just the United States. that: a highly interesting and promising prospect for further intensive study.

Offshore Rectennas

Because siting a rectenna near the coastal pop- ‘Rice Unlverslty, Solar Power Satelllte Offshore Rectenna Study NASA ulation centers that will have most of SPS-gener- CR 1348, November 1980 Appendix B DECENTRALIZED PHOTOVOLTAIC MODEL

Estimating the busbar costs for a house or in- Battery lifetime (deep cycles) –2,000 dustrial plant power station, whether connected to Battery initial costs ($/kWh capacity)–$49/kWh the grid or stand-alone, may involve somewhat dif- Battery O&M cost (¢/kWh discharged) –O.038¢/kWh ferent assumptions than for a central power sta- Battery total cost (¢/kWh discharged): 4.3¢/kWh Battery housing and related costs ($/kWh capacity)– tion. For one thing, the homeowner’s access to cap- $6.4/kWh ital is different than that of the utility. In addition, Backup generator, residential –$306/kW the tax liabilities are different and arise from a dif- Industrial cogenerator steam turbine–$1,446/kW ferent conceptual framework. Percent backup in system with storage–60 percent In order to compare most directly the busbar costs of a decentralized photovoltaic technology with the centralized terrestrial case and with the Sample Calculation solar power satellite, OTA has adopted the case of The following equations apply, assuming there decentralized systems leased by a utility to an in- are no variable O&M costs and no fuel costs. dividual owner. The choice to calculate the costs Busbar costs (¢/KWh) = Ievelized capital cost/levelized this way represents neither a preference nor a pre- output + Ievelized fixed O&M/levelized output diction on the part of OTA for the way in which dis- Levelized capital cost = FCR X initial capital cost persed photovoltaic systems will be marketed in ($/100m2) x 100 ¢/$ the future. The costs so calculated are the costs to FCR (fixed charge rate)= CRF (i/N) + T the utility and do not reflect the price to the consumer. They therefore are directly comparable to CRF (i/N) = capital recovery factor = 1 the busbar costs of electricity from the solar power 1-(1 + i) – N satelIite. where: For homeowners who would prefer not to con- I = weighted cost of capital tinue to rely on a central structure for their power, N = economic life = book life leasing equipment from a utility may not be an ac- T = Ievelized income taxes =(t/(l-t))(CRF( i/N) -1) ceptable arrangement. Many, however, will not x P – (TD – 1/N) wish to accept the relatively high capital invest- TD = tax alIowance for accelerated tax ment and subsequent maintenance which an in depreciation** CRF (i/N) x ((2 x (M – (1/CRF(i/M)))/(M X stallation requires and wilI prefer leasing to pur- (M+ 1)X i)) chase. M= tax life Household and Industrial Photo voltaics: Levelized output = kWh/year/100m2 array costs and efficiencies Levelized fixed O&M= O&M($/100m2/yr)X1000/$ X System assumptions: AF(e,i,N) Array efficiency–18 percent* AF(e,i,N) = CRF(i/N) X (1 – ((1 + e)/(1 + i))N)/(i – e)) X Degradation – 5 percent first year, stable thereafter (1 + e) Systems life– 30 years* where e = apparent escalation rate (inflation rate) Inverterefficiency—90 percent Financial assumptions: Battery efficiency– 75 percent round trip I = 0.10 Array cost — $35 m2* t = 0.30 Additional installation costs assuming roof replace- e = 0.06 ment — $0.0 N = 30 years for array Additional installation costs assuming array flat on = 6 years for batteries 2 roof — $1 3/m M= 20 years Additional installation costs assuming array on ground – Example– 2 $80/m A household 100m2 array mounted on the roof in Operation and maintenance–1 percent of initial costs Boston generates 22,017 kWh/yr: per year Cost of array .$3,500 Lightning protection: Lightning protection $ 500 Household – $500 Power conditioning ., ... $ 650 Industry– $0 Structural support ., .. $1,300 Inversion and power conditioning–$82/kW Total ... ., .$5,950

‘Assumptions of SPS reference system * *A~sume\ sum-of-the-years dlglt~ depredation method

269 83-316 0 - 81 - 19 270 • Solar Power Satellites

O&M costs/year = 1 percent capital costs = $59.56 Busbar costs (¢/kWh) = FCR = 0.12504 74,450—— + 11,233 = 3.9¢/kWh Levelized capital cost= 0.125 X 5,956 X 100 22,017 22,017 = 74,450 ¢/l00m2/year Levelized fixed O&M = 9,705 ¢/100m2/year Appendix C GLOBAL ENERGY DEMAND FORECASTS

1. IIASA’s predictions were influenced by several factors: 1 ) most of the analysis was done prior to the 1979 rise in oil prices; 2) there was an optimistic view of the growth of nuclear capacity (to some 50 to 60 percent of global generating capacity by 2030); 3) participation in the study by the Soviet Union and other centrally planned economies, who for political reasons projected very high economic and energy-use growth rates; 4) low expectations for conservation and alternative energy sources. 2. Predictions of future energy demand are based on estimates of underlying economic and demographic factors, and of the relation between overall economic and population growth and energy demand. IIASA’s population and GDP growth rate projections are as follows:

Population projections by region, high and low scenarios (10’ people) (Finite World, p. 429)

Population base Region year 1975 Projection 2000 2030 I (NA)-North America 237 284 315 II (SU/EE)-Soviet Union/East Europe ...... , 363 436 480 Ill (WE/JANZ)-West Europe/Japan, Australia 560 680 767 Iv (LA)- Latin America 319 575 797 v (AF/SEA)-Southern Africa& Asia ...... 1,422 2,528 3,550 VI (ME/NAF)-Middle East/North Africa 133 247 353 Vll (C/CPA)-China/Central Planned Asia 912 1,330 1,714 World . 3,946 6,080 7,976 NOTES: 1975 data are mldyear estlmates from Unlted Nations Monthly Bulletin of Statistics Januar~ 1978

Historical and projected growth rates of GDP, by region, high and low scenarios (percent/yr) High scenario Historical Scenario projection Region 1950-60 1960-75 1975-85 1985-2000 2ooo-15 2075-30 I (NA) 3.3 34 43 33 24 20 II (SU/EE). 10.4 65 5.0 40 35 35 Ill (WE/JANZ) 50 52 43 34 25 20 Iv (LA) 5.0 61 62 49 37 33 v (AF/SEA). 39 55 58 4.8 38 3.4 VI (ME/NAf) 70 98 72 5.9 42 38 Vll (C/CPA) 8.0 61 50 4.0 35 30 World 5.0 50 47 38 30 27 I + Ill (OECD). 4.2 44 4.3 34 2.5 20 IV + V(Developing) 47 6.5 6.3 51 39 35

Low scenario Historical Scenario projection Region 1950-60 1960-75 1975-85 1 985-2000 2000-15 2015-30 I (NA) 3.3 34 31 20 11 1.0 II (SU/EE). 10.4 65 45 3.5 2.5 20 Ill (WE/JANZ). 50 52 32 2.1 1.5 1.2 Iv (LA) 5.0 6.1 47 3.6 30 30 v (AFI/EA) 39 55 48 36 28 24 VI (ME/NAf) 70 9.8 56 4.6 27 21 Vll (C/CPA) 8.0 61 33 3,0 25 20 World 50 50 3.6 27 19 17 I + Ill (OECD) 42 44 3.1 21 13 11 IV + V + VI (Developing) 47 65 5.0 38 29 26

SOURCE Energy In a F/n/te World, A Global $ystems Ana/ys/s, Energy Systems program croup lnt~matlonal In$tltute for Applied svstems Analvsls (Cambridge, Mass Balllnger Publlshlng Co , 1981) p 431

271 272 ● Solar Power Satellites

3. In general, the IIASA study places great emphasis on the development of nuclear power, and especially on an explosive growth in fast breeders after 2000. Although a number of countries, including France, Japan, and the Soviet Union, have announced aggressive plans to install breeders over the next several decades, it should be remembered that questions still remain as to breeder reactor safety, reliability and operating costs. (See ch. 6 for a comparison of breeders and other baseload power sources.) IIASA’s high expectations for breeder development are by no means universalIy shared. Percent of global secondary electrical demand met by nuclear power–llASA

1975 2000 – 2030 Low High Low High Conventional reactors 20 271 294 19,2 22.9 Breeders 0.0 044 067 40,6 38,2 Total 20 275 303 498 611

SOURCE Energy in a Finlte World, p 580 4. These higher estimates for the amount of coal used for synfuels depend on a number of assumptions, including the greatly increased use of nuclear power to replace coal in electricity generation. 5. The following CONAES study estimates for the U.S. should be compared with the IIASA estimates for North America (see No. 1, p. 271 for population and economic figures; assume Canadian population is approximately 10 percent of total), Population in 2070—279 million (Bureau of Census Series I I projection, with no allowance for illegal immigration). z Average growth in GNP, 1980-2010—2 percent per year ] Primary energy demand (Quads) CO AfAES4 [United States on/y - 2010) Low [A] Medium [B] High (C) 70 90 130 IIASA 5 (North America-Canada approximately 10 percent of total) 2000 2030 Low 99 131 High 120 180 Direct comparisons are difficult because of the different time frames and geographical areas examined. The CONAES A projection, no growth in energy demand over the next 30 years, has no parallel in the IIASA study. The IIASA low scenario is slightly higher than the CONAES series B projections; the high scenario is approximately equal to CONAES C. Population estimates are compatible; however, CONAES’ 2 percent per year average GNP growth rate is much lower than IIASA’s high scenario. It is approximately equal to the low scenario forecast. Insofar as the two studies are comparable, CONAES’ estimates are somewhat lower than IIASA’s, with the more radical CONAES A projection much lower. The difficulty lies in determining what this might mean on a global scale. Lower estimates for the United States may hold true for other Western industrialized areas, but cannot be extended to developed centrally planned economies or to the developing world, where growth rates are expected to be higher than in the OECD. The CONAES report itself states that: “Even if energy conservation in the United States accomplishes a great deal domestically, it will be more than offset by demand growth in countries at the ‘takeoff’ stage of development “ Global energy consumption in 2010 is estimated to be probably three to four times what it is now, with electrical consumption rising at even faster rates. b 6. The Case Western Reserve and World Energy Conference estimates for future energy and electricity use are as follows:

‘Energy In Transltlon, 1985-2010 (Washington, D C , National Academy of S, Iences, 1979), p 626 z I bid , p 643 ‘Ibid , p 645 ‘1 bid , p 668 ‘Energy In a Ftnfte VVor/d A G/oba/ Systems Ana/ysls, Energy Systems Progr~m Group, I nternatlona I I nstltute for Appl led Systems Analysis (Cambridge, Mass Ballinger Publishing Co , 1981), p 44o ‘Energy In Transition, p 626 )

Appendix C—Global Energy Demand Forecasts ● 273

Energy demand (Quads

1975 2000 2025/2020 CWRU WEC C WRU WEC OECD ...... 146.8 3453 266.2 618,8 395.1 SU/EE ...... 55.0 98.3 126,1 205.7 235.0 Developing, ....,... 37.7 103.0 174.0 296,8 434.2 Global...... 239.5 5466 566.3 1,121.3 1,064.3

End-use electricity demand (Quads electric) (estimated by Clav. and Dupas from model data)

1975 2000 2025/2020 CWRU WEC CWRU WEC OECD ., 12,5 55.8 386 106,9 66.1 SU/EE : 3.9 152 216 353 353 Developing ., 1.8 102 135 40.2 465 Global, 18,2 812 737 182,4 1479 Compare these figures to the lower IIASA estimates in figure C-1. The worldwide distribution of LEPP in 2025 for the CWR model is:

Figure C-1 .—Large Electric Powerplants in 2025

160 140 120 100 80 60 40 20 0 340 320 300 280 260 240 220 200 180

60 F

E 40 D

c 20 B A 0 a b 20 c

d 40 e

f 60

8 Nb per zone

“Preliminary Evaluation of Ground and Space Solar Market in 2025, ” 29th IAF Congress, October 1978 274 ● Solar Power Satellites

7. The World Bank report on Energy in the DevelopingCountries projects energy use and demand over the next decade. From 1973-78, growth in electricity consumption in developing countries averaged 8 percent per year, compared to 3.5 percent in developed countries; the Bank estimates this will continue through the 1980’s. The Bank reports that in 1980 Oil-Importing De- veloping Countries (OIDC) invested $18.5 billion in electric power (70 percent for generation, 20 percent for distribution, 10 percent for transmission) out of a total of $24.6 billion invested in all forms of energy—over 75 percent. This is expected to more than double, to $39.7 bilIion/year, by 1990. The amount of installed capacity is estimated to be 241 gW in 1980, rising to 523.7 in 1990. Large increases will be made in gas and nuclear fired generators though absolute levels will remain relatively low; hydro power will remain the largest single source, at approximately 40 percent of the total, with oil generation declining rapidly from 37 to 25 percent. ’

‘Energy In the Deve/op/ng Countrle>, World Bank, August 1980, pp 42-49 Appendix D ENVIRONMENT AND HEALTH

DOE Comparative Environmental sites as opposed to the large contiguous land Assessment space needed for SPS and CTPV. The nuclear technologies require the least total land area. The Department of Energy (DOE) has sponsored ● While each technology would encounter ma- comparative environmental assessments between terial constraints, none appear insurmount- the following energy technologies: conventional able. Water requirements are listed in table coal (CC), coal gasification/combined cycle (CG/ D-2. CC), light water reactor (LWR), liquid metal fast ● All technologies considered are not energy breeder reactor (LMFBR), magnetically confined fu- producers when operating fuel requirements sion (MC F), central station terrestrial photovoltaics are excluded from the calcuIations. Otherwise, (CTPV), and the reference system solar power satel- only the inexhaustible technologies are net lite (SPS). An analysis was performed to quantify producers. and compare the effects of these technologies on environmental welfare (i. e., effects that are not Microwaves—Ionosphere Interaction directly related to health and safety such as weather modification, resource depletion and noise), While only a small fraction of the incident health and safety and resource requirements. Un- microwave energy is absorbed by the ionosphere, quantifiable health impacts were also identified, the resultant heating at microwave frequencies but were not ranked (see table D-l). The major con- could significantly alter the thermal budget of the clusions include:1 ionosphere. In the lower ionosphere (D & E regions) With respect to effects on the environmental a phenomenon called “enhanced electron heating” welfare, all of the energy options except for can occur if the microwave heating overwhelms coal (because of CO2 climatic alterations and the natural cooling mechanisms of the ionosphere. acid rain) are roughly comparable in magni- The resultant heating can then affect electron-ion tude, while different in nature. recombination rates, changing ionospheric den- As shown in figure D-1, it is apparent that the sities, or drive additional interactions. Furthermore, quantified public and occupational health in the E region it is possible that the microwave risks of all the technologies except coal are heating could enhance natural density irregulari- about the same in magnitude, but different in ties called “sporadic E“ that can cause scintilla- cause. The health effects that were not in- tions or scattering of radio frequency signals par- cluded in this analysis are Iisted in table D-1. ticularly in the very high frequency (VHF) band, Land use comparisons indicate that the land e.g., citizen-band and some television bands. z area required for SPS would be similar to that New experiments and theories were needed to for CTPV. Coal utilizes slightly less total land understand the effects of an SPS microwave beam area. This is distributed among many mining traveling through the ionosphere (an example of .—. ‘Program Assessment Report, Statement of Flndlngs, Satell Ite Power ‘W E Gordon and L M Duncan, “Reviews of Space Science–SPS im- Systems, Concept Development and Evaluation Program, DOE/E R-0085, pacts on the Upper Atmosphere,” Astronautics arid Aeronautics, july/ November 1980 August 1980, VOI 18, NoS 7,8, p 46

Table D.1 .—Unquantified Health Effects”

Solar technologies (CTPV, SPS) Nuclear technologies (LWR, LMFBR, MCF) Exposure to cell production emissions and hazardous System failure with public radiation exposure (including waste materials. disposal). Chronic low-level microwave exposure to the general and Fuel cycle occupational exposure to chemically toxic materials. worker populations (SPS). Exposure to HLLV emissions and possible space vehicle Diversion of fuel or byproduct for military or subversive uses. accidents (SPS). Worker exposure to space radiation (SPS). Liquid metal fire (LMFBR, MCF only). atW unquantified health effects were identified for the coal SYStem used. SOURCE: Program Assessment Report, Statement of Flnr)vrgs, Satellite Power Systems, Concept Development and Evaluation Program, DOEIER-0085, November 1980.

275 276 Ž Solar Power Satellites

LORAN-C), and MF (300 kHz to 3 MHz, AM).3 How- ever, neither Arecibo nor Platteville is equipped to generate a beam of SPS frequency and power density. Instead the experiments were performed at lower frequencies and power densities and the results extrapolated to SPS conditions using the scaling law: P SPS P HF ——= f2 SPS f2 HF

where Psps and PHF are the power of the SPS beam (i.e., 23 mW/cm2) and heating facility beam respectively, and f is the frequency of the beam (i. e., fsps = 2.45 GHz).4 This extrapolation is thought to be valid only if the primary heating mechanism is ohmic (i. e., heating by CoIIisions between ions). This assumption has been verified over a limited range of frequencies. By increasing the Platteville and Arecibo power densities and maximum frequency, confidence in the sealing theory could be improved. Experiments are also needed to test the effects of localized ionosphere heating on telecommunication systems operating at frequencies above 3 MHz. In the upper ionosphere (F region), effects on Table D.2.—Water Requirements for telecommunications and on the SPS pilot beam Alternative Energy Technologies stem primarily from a phenomenon called “thermal self focusing” which results when an elec- Cubic meters tromagnetic wave propagating through the iono- Technology per gigawatt year sphere iS focused and defocused as a resuIt of nor- 6 Conventional coal...... 77x 10 mal variations in the index of refraction. As the inci- Light water reactor...... 37x 10’ Liquid metal fast breeder reactor ...... 32X 1O6 dent wave refracts into regions of lesser density, Coal gasification/combined cycle...... 14x 106 the electric field intensity increases. Thermal pres- Magnetically confined fusion ...... 39x 106 sure generated by ohmic heating drives the plasma 3 Satellite power system...... = 1 x 10 from the focused areas, thereby amplifying the ini- Central station terrestrial photovoltaics . . . = 1 x 104 tial perturbation. Although the heated volume in SOURCE: Program Assessment Report, Statement of Findings, Satellite Power the D and E regions is confined essentially to that Systems, Concept Development and Evaluation Program, DOE/ of the beam, the heated particles in the F region ER-0085. November 1980. wiII traverse magnetic field Iines so that large-scale field-alined striations or density irregularities form. These striations reflect VHF and UHF radiowaves specularly, causing interference and the abnormal what is called “underdense” heating) because long-range propagation of the signals. Less is known about the effects of SPS-type almost all of the data generated in the past has focused on the “overdense” case, i.e., where the heating in the F region than the D and E layers. The ionospheric density is great enough to reflect the in- power scaling law in the upper ionosphere may differ from that in the lower regions (i.e., the scaling cident heating frequency. law for thermal self-focusing instability may follow Two high frequency (HF) ground-based heating 3 2 facilities have been used to simulate SPS heating in a 1/f dependence rather than the 1/f dependence valid for ohmic heating). Experimental data is the lower ionosphere. At Arecibo, Puerto Rico, ionospheric physics and heating mechanisms have been studied. The Platteville facility in Colorado Fnv/ronmental Assessment for the Satell/te Power System – Concept has tested the effects on specific radio frequency Development and Eva/uatlon Program – Effects of /onospher/c Heat/rig on Te/ecomm[/n[catlons, DOE/NASA report, DOE/E R 10003-TI, August 1980 navigation and broadcasting systems, namely VLF ‘t nv/ronmenta/ Assessment for the Sate//lte Power System – Concept (3 to 30 kHz, OMEGA), LF (30 to 300 kHz, Det eloprrrenf and Eva/uat/on Program, DOE/E R-0069, August 1980 Appendix D—Environmentant Health . 277

needed to improve theory and test the effects on nuclei could have a measurable, although short- telecommunications. term effect on weather. In particular, under certain A single SPS would cause the indicated iono- meteorological conditions, heat and moisture sphere perturbations within a VoIume approximate- could enhance convective activity, and induce ly equal to the power beam dimensions. For muiti- precipitation. While the frequency and degree of ple SPS deployments (e.g., the 60 systems defined such effects are uncertain, none of the projected in the Reference Design) the cumulative effects of weather effects are thought to be serious. Cloud- the perturbed volumes must be determined. One condensation and ice-forming nuclei would also be important question obviously concerns the possi- produced in the ground cloud. The effects of the bility of coupling between adjacent volumes, and latter on weather cannot be reliably estimated at determining beam separation constraints to elim- this time. The high abundance of the former in the inate mutual coupling. 5 ground cloud is thought to be meteorologically important; cloud-condensation nuclei could change The Effects of Space Vehicle Effluents the frequency and persistence of fog and haziness. on the Atmosphere It has been suggested that because of the large size and frequency of HLLV launches, cumulative ef- SPS reference system rocket exhaust products fects might occur. More research is needed not would affect every region of the atmosphere. In only for SPS, but of weather and climate phenom- table D-3, the atmospheric effects of most concern ena in general. are listed. As part of its assessment, DOE has also Research needs include: ● identified possible means of resolving these uncer- refine and test ground-cloud formation and tainties in the event that an SPS program is pur- transport predictive models as well as weather sued. and climate models, ● update ground-cloud composition as systems Troposphere 6 are developed; conduct appropriate observations of rocket launches, SPS launch effluents injected into the tropo- ● study effects on local weather of prospective sphere could modify local weather and air quality launch sites including possible cumulative ef- on a short-term basis. These changes would be due fects, and ● primarily to the formation and dispersion of a consider NOX effects and possible ways to launch site ground cloud that consists of exhaust reduce levels given a range of Iikely future gases, cooling water, and some sand and dust. standard levels and meteorological condi- While sulfur dioxide, carbon dioxide, and carbon tions; refine and validate theoretical models monoxide concentrations would not be significant, for simulating NOx dispersion, nitrogen oxides and water vapor are of concern. Nitrogen oxides (NOx, especially NO, in the Stratosphere and Mesosphere ground cloud, might under certain conditions, present problems for air quality. The projected ground The upper atmosphere has received considerable cloud concentrations themselves are not thought public attention in the last decade, largely as a to violate the short-term national ambient air qual- result of a number of studies examining the effects ity standards that are expected to be promulgated on the stratospheric ozone layers (which shield the in the near future, but if ambient concentrations Earth from biologically harmful ultraviolet radia- are already high, a violation could occur. NO and tion) of the supersonic transport, fluorocarbons, X and the biological generation of nitrous oxide SOX in the ground cloud could contribute to an in- 7 8 crease in localized acid rain but this is expected to etc. There is concern that while the potential ef- be small. fects on climate and terrestrial life of altering the The ground cloud will also contain about 400 to upper atmosphere couId be serious, our under- 650 tons of water. While having a negligible impact standing of the physics and chemistry of the region on air quality, water vapor, especially in associa- is Incomplete. For example, it is known that the tion with launch-generated heat and condensation chemical composition of the upper atmosphere plays a key role in maintaining the Earth’s thermal budget and is directly linked to the dynamics, cir- ‘E Morrison, National Telecommunlcatlons and Information Admln- Istratlon, private communlcatlon, Feb 17, 1981 ‘Most of this section IS derived from Ertv/ronrnenta/ Assessment for the The Aero\ol Threat, ” Newsweek, Oct 7, 1974, pp 74-75 Satell/te Power $ystem, Concept Development and tvaluatlon Program, “( I Imatl( Impact Committee, NRC, Fnv/ronmenta/ Impact of $tra(o- DO E/ ER-0069, August 1980 \phorlr I /IRh/ NAS, Washington, D C 1975 278 ● Solar Power Satellites

Table D-3.—Atmospheric Effects

Known Uncertainty Resolution Launch vehicles will inject large amounts of The frequency of occurrence of suitable Design and implement appropriate water vapor and thermal energy into meteorological conditions. The extent of observational programs associated with localized regions of the planetary boundary injection of cloud condensation and ice- rocket launches and conduct laboratory layer. The potential for inadvertent weather forming nuclei. The duration and scale of experiments to characterize better nuclei modification under suitable meteorological the effects of the nuclei and the thermal formed in the combustion of rocket conditions exists. energy inputs. The importance of propellant. Refine, test, and validate anticipated small increases in cloud theoretical models suitable for simulating population, precipitation, haze, and other the effects of rocket launches. Examine the meteorological effects to the environs of meteorological conditions appropriate to the launch site. potential launch sites. Evaluate the importance of changes in those conditions to the environs of those sites. Exhaust emissions and reentry products Chemical-electrical interactions in the Design and implement experiments aimed at from reference system heavy-lift launch ionosphere, the effectiveness of mitigating critical problems. Measure and analyze vehicles and personnel orbit transfer strategies, and effects on interactions through rocket experiments vehicles will modify ion densities at high telecommunications. combined with telecommunications tests. altitudes. In particular, injection of H2O and Apply results to improve theoretical

H 2 in the F-region will cause partial prediction capabilities. Provide guidance for depletion of the F-region. system operational mitigating strategies and alternatives. Ground clouds formed by HLLV launches Exact value of NO2 air quality standard to be Utilize a range or anticipate probable

will contain relatively high concentrations set. Actual ground-level concentrations of “standard values” for NO2 including the

of NOX that, in combination with effluents NO2 associated with vehicle launches under existing standard for California. Refine, from sources in the launch site environs, various ambient meteorological and air test, and validate existing modeling tech- will exacerbate existing air quality problems quality conditions typical of anticipated niques for simulating formation and

under certain conditions, launch sites. dispersion of NO2 in ground clouds. Utilize existing and acquire new data related to rocket launches for this purpose. Prepare a

climatology of expected NO2 ground-level concentrations under a range of meteorological and ambient air quality conditions typical of anticipated launch sites. HLLV flights will deposit a large amount of The quantitative increases. Whether the Obtain a better understanding of the natural water and hydrogen above 80 km. The globally averaged increase in water content hydrogen cycle and develop and implement globally averaged water content is likely to will be sufficient to alter thermospheric models to simulate the effects of rocket be increased by amounts ranging from 8 composition or dynamics in a significant propellant exhaust on a global scale. percent at 80 km to factors of up to 100 or way. Whether the increase will result in a more above 120 km. The injected water and chronic, global-scale partial depletion of the hydrogen will increase the natural upward ionosphere of sufficient magnitude to flux of hydrogen by as much as a factor of degrade telecommunications. Whether the 2. increased hydrogen flux will significantly increase exospheric density and/or modify thermospheric properties.

Injection of water vapor from HLLV The scale and persistence of the clouds, Design and implement observational launches in the altitude range of about 80 especially in view of poorly understood programs to obtain data on the occurrence to 90 km is likely to result in the formation co m p et i n g cooling and h eating and characteristics of high-altitude clouds of noctilucent clouds. mechanisms. Whether cumulative effects formed during rocket launches. Improve could arise and lead to globally significant knowledge of the natural atmosphere near effects such as changes in climate the mesopause and develop and implement models to better simulate the effects of water and hydrogen injection on cloud formation. Reference system personnel and cargo orbit Ultimate fate of effluents. Potential impacts Design and implement experiments in the transfer vehicles would inject substantial such as increased radiation hazards to magnetosphere to obtain data for improving amounts of mass and energy into the space travelers, auroral modifications, understanding of magnetospheric magnetosphere and plasmasphere. telecommunications, and terrestrial utility phenomena of interest and provide system interference, enhanced airglow emissions, design guidance where appropriate. and changes in weather and climate. —.—. SOURCE: Program Assessment Report, Statement of Firrdmgs, Satellite Power Systems Concept Development and Evaluation Program, DOEIER-0085, November 1980. culation and climate of the troposphere, but the els 10 One dimensional models predicting global mechanisms that couple the two regions are ex- average vertical transport of atmospheric constitu- tremely complex and not well understood.9 The ents are used most extensively, although less-refin- SPS assessment relies mostly on theoretical mod- ed two and three dimensional models are also

‘tncyc/oped/a of ‘ic(ence and Technology VOI 1 (New york McCraw- HIII Book Co , 1977] “’~u~ra note b Appendix D—Environment and Health ● 279

available. High-altitude experiments are needed to alter significantly the global climate, but in view of improve atmospheric theory and the data base for the poor understanding of the coupling between the SPS assessment. the mesosphere and troposphere, this expectation The most significant SPS impacts would arise requires further analysis. A large unknown is the ef- from the injection of rocket effluents, especially fect of the excess water content on temperature

water vapor and reentry NOX directly into the that may affect the likelihood and persistence of stratosphere and mesosphere. SPS vehicles emit the clouds. 7 CO, into the upper atmosphere but the amount is In the stratosphere, detectable depletion or extremely small relative to existing levels and to enhancement of the ozone layer from the emission the quantities generated by the consumption of of water and nitric oxide would be unlikely. While fossil fuels. The effects of any impurities in the water vapor tends to decrease ozone, nitric oxide rocket fuel, such as sulfur would be negligible. tends to increase it. The net effect of SPS reference Thermal energy is also injected by HLLV and PLV system effluents is thought too small (i. e., either a launches, but the effects are thought to be minor decrease or increase on the order of 0.01 percent) and transient. relative to the natural fluctuations of the ozone Increases in water vapor would be of concern concentration. 8 This conclusion requires further because its natural abundance in the upper at- verification as it is based on one-dimensional mosphere is very low. The most recent estimates in- models. dicate that the increase in the globally averaged In addition to the formation of noctilucent concentration of water vapor due to 400 HLLV clouds and perturbations of the ozone layer, the flights per year would be about 0.4 percent in the water vapor deposited in the stratosphere and stratosphere (30 km) and 8 percent in the upper mesosphere might contribute to a chronic partial mesosphere (80 km). 2 Increases near the latitudes depletion of the ionosphere. However, this is ex- at which the water vapor was emitted could be pected to be very small in comparison to the local higher due to a so-called “corridor effect” with in- depletions caused by rocket emissions directly into creases in water content up to 15 percent above 80 that region. ’9 Climatic effects might occur from km. ” At 120 km and above, it is estimated that the changes in the chemical composition of the upper global water content could be increased by a fac- atmosphere, although at present it is not possible tor of 100 or more. 4 to assess reliably any potential effects. Research The production of nitric oxide from the reentry priorities for SPS upper atmospheric effects in- of HLLVS is expected to increase significantly the cIude naturalIy occurring NO concentration and to ex- X ● hibit a pronounced long-term corridor effect in the update emissions inventory and estimates of 5 reentry NO ; NO distribution of the mesosphere. Stratospheric X X ● estimate magnitude of corridor effect and NO levels would also be altered due to downward x study possible temperature feedback mecha- diffusion from the mesosphere, but would be con- nisms; fined mostly to the lower stratosphere where their ● identify and augment existing experimental impact wouId be negligible. programs to make high-altitude measurements In the mesosphere, the injection of water could of water and NO concentrations, study high- induce luminous, thin, or “noctilucent” clouds of X ice crystals in the vicinity of the rocket exhaust. It altitude water release data; ● is estimated that the cloud would expand from a assess the possibility and climatic impacts of 2 16 noctilucent clouds; size of 1 to 1,000 km over 24 hours. This finding is ● develop scenarios of SPS impacts on a number based on theoretical calculations and observations of different background conditions including of other rocket launches that deposited far less future increases of C0 ; water into the mesosphere than that which is pro- 2 ● document and verify effects of effluents that jected for the HLLVS. The clouds are not thought to are now thought to have a minor impact on the

‘ ‘ Iblcl upper atmosphere; and ‘‘Iblcl ● determine telecommunicate ions effect of ‘ ‘Program A~ses\ment Report, Statement oi Finding>, Satelllte Power chronic, partial depletion of ionosphere (from Systems Concept Development and Evaluation Program, DOE/NASA Report, DOE/E R-0085, November 1980 water vapor injected in the stratosphere and “Environmental A$$es$ment for the $ate//tte Power \y$tem – Concept mesosphere). Development and Eva/ua tlon Program – A tmo~pherlc E ffect$, DOE/E R-0090, November 1980 ‘Ibid ‘‘Supra note 9 “$u prc? note 9 “Supra note 6 ‘5u[)r~ note 6 280 ● Solar Power Satellites

Ionosphere ozone layer, air conductivity, and hence climate could be affected by the effluents but no reliable The ionosphere is used extensively in telecom- conclusions can be made at this time. munication systems to propagate and reflect radio The effects of rocket exhaust products are better waves. The injection and diffusion of SPS launch understood in the F-region, but the impact of SPS propellants into the ionosphere could alter the den- effluents is still not certain. This region is sity of the electrons and ions that are responsible dominated by oxygen atoms that recombine more for the unique properties of the ionosphere, there- slowly with electrons than their molecuIar counter- by degrading the performance of the telecommuni- parts in the lower ionosphere. Exhaust products cations systems. Other effects might also occur, such as water, hydrogen and C02 emitted in the F- such as enhanced airglow and increased electron region become quickly ionized by charge exchange temperature, but the Iikelihood and consequences reactions with the existing atomicions.24 These of these impacts are yet to be determined. 20 molecular ions rapidly recombine with the iono- A reliable assessment of the effects of launch ef- spheric electrons, thereby causing a region of pro- fluents on the D-region of the ionosphere cannot be nounced depletion known as an “ionospheric made at this time. However, two apparently coun- hole.” It has been estimated that for each POTV z teractive effects have been postulated. ’ The emis- launch (which would occur once or twice a month), sion of water vapor into the D-region is Iikely to an ionospheric hole with an area two to three times deplete the ionospheric plasma density. This would the size of the continental United States25 would be reduce radio wave absorption in the daytime iono- formed and persist for 4 to 16 hours. z’ Each HLLV sphere and result in propagation anomalies. On the launch (one or two per day) would produce a hole 27 other hand, NOX, produced by frictional heating about one-tenth the size, lasting 4 to 12 hours. It during reentry, could engender the formation of has been suggested that a long-term low-level ions in the D-region. It is believed that enough NOX depletion on the order of 10 percent would develop would be deposited in the region to compensate for in a ring around the launch latitude as a result of the reduction of the plasma due to water vapor. A multiple launches .28 The probable consequence of recent lower ionosphere experiment suggests that this depletion ring is a small perturbation of VLF, anomalies in the propagation of VLF signals were H F, and possibly VHF wave propagation. due to the effects of rocket effluents. ” While the These findings were based on a number of theo- experiment was not conclusive, it is clear that de- retical models of the ambient and perturbed F- tectable effects might occur that warrant further region as well as several observations of rocket study. effluent-induced ionospheric holes. The models are As in the D-region, current understanding of the fairly well developed and theoretical mechanisms launch effluent effects on the E-region is not very are well understood, but care should be taken in advanced. Rocket propellants would be directly in- scaling up radiowave propagation effects. Further jected only into the lower E-region because HLLV study is required in order to predict accurately the 23 engines would be shut off at 124 km. Some ef- location, size, movement, and lifetime of the hole fluents would enter the upper E-region by upward as well as the cumulative effects of multiple diffusion. Exhaust products emitted above the E- launches. 29 An observation of ionosphere depletion region in LEO by PLVS, POTVS and HLLV could also inadvertently took place after a 1973 skylab flight diffuse and settle downwards. The impacts of these that produced a hole 1,000 km in radius.30 In 1977, effluents on the E-region, however are very uncer- experiments were conducted to purposefulIy pro- tain. It is possible that the deposition of ablation duce an ionospheric hole.31 The experiments, materials during reentry could augment a radio named Project LAGOPEDO tended to confirm the signal altering phenomenon called “sporadic E“ in which regions of greatly enhanced electron concentration are created. In addition, the coupling “E Bauer, Proceedings of the Workshop on the Mod/ f/cation of the Up- per Atmosphere by the Sate///te Power System (SPS) Propu/slon Eff/uents, between the ionosphere and magnetosphere, the DO E/NA$A Report Conf -7906180 “Supra note 14 ‘OSupra note 9 “Supra note 6 “ Ibid ‘7 Supra note13 “C Meltz and J A Darold, “VLF OMEGA Observations of the iono- ‘Ulbld spheric Disturbance produced by an Atlas HEAO-C Launch, ” In Pro- “Supra note 9 ceedings of the Workshop/Symposium on the Prellmlnary Evaluation of ‘“M Mendlllo, C Hawkins, and J Klobuchar, An Ionospheric Tota/ the Ionospheric Disturbances Associated WIIh the HEAO-C Launch, With Electron Content Disturbance Associated With the Launch of NASA Applfcatlons to the SPS Ertvfronmental Assessment, M Mendlllo and B $k ylab, Air Force Cambridge Research Laboratories, July 1974 Baumgardner (eds ), DOE/NASA report Conf 7911108, August 1980 “ Pongratz, et al , Lagoped~Two F-Region Ionospheric Dep/etion Ex- 2’Supra note 9 perlment~ Los Alamos Scientlflc Laboratory, LA-U R-77-2743 Appendix D—Environment and Health . 281

theory. Recently, DOE took advantage of the Thermosphere and Exosphere launch of NASA’s High Energy Astrophysical Ob- servatory (HEAO-C) by an Atlas/Centaur rocket in As discussed above in the Stratosphere and Meso- order to monitor the resultant large-scale (1 million sphere summary, HLLV flights are predicted to to 3 million km2) effIuent-induced ionospheric hole, substantially increase the natural water content which persisted for approximately 3 hours.32 The above 80 km. One consequence of this excess preliminary finding indicates that no severe long- could be an increase and, perhaps, doubling of the term impacts on HF radio signals occured as a upward flux of hydrogen atoms that result from the result, but that VLF transmissions (14 KHz) could breakdown of the molecular water vapor as well as have been affected.33 On the whole, not enough is molecular hydrogen emitted above 56 km by 37 known about SPS-induced ionospheric holes to HLLVS, PLVS and POTVS. While it is fairly certain make conclusions about their impacts on telecom- that an increase in the hydrogen flux would result, mu n i cat ions. the consequences of a perturbed hydrogen cycle In addition to telecommunication effects, other are quite uncertain. The hydrogen escape rate into potential effects of SPS rocket effluents deposited outer space could increase. Accumulation of in the F-region have been suggested .34 Enhanced hydrogen above 800 km might also occur, thereby airglow emissions could affect astronomy, remote possibly altering thermospheric and exospheric sensing, and surveillance systems. Past observa- dynamics and enhancing satellite drag. tions have noted enhancements on the order of 10 Research is needed to: kilorayleighs for certain visible and near infrared . improve understanding of the natural hydro- emissions. 35 The magnitude and significance of SPS gen cycle and dynamic processes of the ther- airglow emissions warrants further study. The injec- mosphere and exosphere; and tion of water vapor in the F-region might also per- ● design models to quantify hydrogen increases turb the thermal budget of that region. This would and simulate SPS effects on a global scale. increase the ratio of cooling by radiation and perhaps alter the Van Allen belts and the amount Plasmasphere and Magnetosphere of ionizing radiation in space. Also, as noted SPS reference system effects on the plasma- previously, the number of hydrogen atoms emitted sphere and magnetosphere result primarily from by HLLV launches in the upper thermosphere and the emission of COTV argon ions and POTV hydro- exosphere could be comparable to the number gen atoms as the vehicles move between LEO and naturally present. This could increase satellite 38 drag, alter the Van Allen belts, and affect radio GEO. The impacts of these effluents could be great, because the energies and number of ions and communications. The water budget of these regions is not well understood however, and so the atoms injected would be substantial relative to the ambient values. Unfortunately, the magnetosphere probability of these effects is not known. and plasmasphere are poorly understood. While Research should focus on the following areas: some potential SPS impacts have been identified as ● improve understanding of D&E region effects; shown in table D-4, their probability and severity ● refine studies of F-region ionospheric holes in cannot be assessed since no experimental data rele- order to predict location, size, movement, and vant to SPS exists for these regions. I n particular, lifetime; the consequences and the mechanism of interac- ● test effects on telecommunications systems tion between the argon ions and the ambient using D, E, and F regions; and plasma and geomagnetic field must be explored. ● assess airglow effects perhaps with the in- In addition to the exhaust products, the satellites volvement of the remote sensing and astron- 36 themselves could also have an impact on the mag- omy communities. netosphere by obstructing plasma flow, or producing dust clouds, electromagnetic disturbances, space debris, visible and infrared radiation, and high-energy electrons.39 Little emphasis has been placed on these potential effects, however, “M Mendlllo and B Baumgardner, Proceedings of the Workshop/Sum- because they are thought to be minor and easily poslum on the Preliminary Eva/uatlon of the Ionospheric Disturbances Associated W/th the HEAO-C Launch, W/th Appl{catlons to the SPS Env/- reinedied. ronmenta/ Assessment, DOE/NASA Report Conf 7911108, August 1980 “Ibid “Supra note 9 “Supra note 6 ‘5 Supra note13 ‘“Supra note 9 ‘blbld “lbld 282 ● Solar Power Satellites

Table D-4.—Satellite Power System Magnetospheric Effects

Effect Cause Mechanism System/activities impacted 1. Dosage enhancement of O + and Ar + in magneto- Thermal heavy ions suppress —Space equipment trapped relativistic sphere due to exhaust and ring-current-ion cyclotron —Modification of human electrons plasmasphere heating turbulence, which keeps space activity electron dosage in balance in natural state 2. Artificial ionospheric Ionospheric electric field Beam induced Alfven shocks —Powerline tripping current induced by argon beam propagate into ionosphere —Pipeline corrosion (probably unimportant) 3. Modified auroral response Neutrals and heavy ions in Rapid charge-exchange loss —May reduce magnetic storm to solar activity large quantities of ring-current particles interference with Earth and space-based systems 4. Artificial airglow 3.5 keV argon ions Direct impact on atmosphere —Interference with optical from LEO source Earth sensors 5. Plasma density disturbance Plasma injection Plasma instabilities —Signal scintillation for on small spatial scale space-based communications

SOURCE: Environmental Assessment for the Satellite Power System, Concept Development and EvaluationProgrammAtrnosptreric Effects, DOEIER-0090, November 1980.

If an SPS program is conducted, it is clear that shown in figure 40, p. 211. Atmospheric scattering the design of transport vehicles for the outer re- and attenuation due to absorption, in addition to gions of the atmosphere and the environmental as- losses at the rectenna would reduce the usable sessment of their impacts in these regions will be power at the rectenna to 5,000 MW. The following closely linked. Possible methods of reducing ad- radiative effects are the most important for the verse effects include the use of both chemical and reference system (fig. D-2): argon ion engines or an alternative propulsion sys- ● Out-of-band radio frequency emissions. The tem in the COTV, and lunar mining. reference system’s klystrons are estimated to Near term studies include: radiate energy at the following harmonic fre- • design and implement experiments in the quencies: 40 magnetosphere and the laboratory to test SPS Power level effects and increase theoretical understanding Frequency (C HZ) (times 6,720 MW) of magnetospheric phenomena. 245- (central frequency) 1 490- (second harmonic) -50d B(10-5) 7 35- (third harmonic) -90d B(10-9) The Electromagnetic Characteristics of 980- (fourth harmonic) -lOOd B(10 1O) the Alternative SPS SatelIites Although it is known that the antenna patterns for these frequencies would be rather dif- Microwave Satellites ferent from that of the reference system, current antenna theory is inadequate to predict a The satellite would generate microwave power detailed spatial pattern. at a frequency of 2.45 GHz or some other central Spurious sideband noise generation from radio frequency, thermal radiation, and reflected the klystrons outside of the central frequency sunlight at all solar wavelengths. In addition, it is estimated to be no greater than – 200 d B of would generate some power at multiples of the the central frequency at a separation of 8 to 10 central frequency (harmonics), and also spurious MHz from the center frequency. Filtering may noise on either side of the central frequency. be able to reduce this to levels which would Because the reference system is the only system for not cause appreciable interference in most which an attempt has been made to characterize a cases This is one constraint in the separation system completely, this report will use its necessary between an SPS frequency assign- characteristics as an illustrative model for all ment and the boundaries of the 2.45 GHz In- microwave systems. ternational Scientific and Medical band. These The space antenna would radiate a total of 6,720 considerations apply after the klystron tubes MW of microwave power towards Earth. The refer- have warmed up. Since, on the average the —— ence system design calls for the power distribution 4 ‘C, L) \rndt and L Leopold, “Environmental Conslderatlons for the over the face of the satelIite antenna to be gaussian MI( rowav(, [learn from a Solar Power Satel I lte, ” I )th /nter\oclety Energy with a 10-d B taper. The resuIting beam pattern is ( of)kerslrv) I nglneer~ng ( orrferrwce, San Diego, Callf , August 1978

Appendix D—Environment and Health ● 283

Figure D-2.–Overview of Potential SPS Electromagnetic=Compatibiiity impacts

noise & harmonics

SOURCE: Power (SPS), Concept Development and Evaluation Program p. 43,

100,000 klystrons in the antenna can be ex- ways41 42 1) diffuse reflections from the solar pected to fail at a rate of five per day, out of arrays, the antenna and the underlying struc- band radiation as they fail and as they warm ture; 2) specular mirror-like reflections from up after being replaced may be greater than the solar arrays and the antenna; 3) glints or during their operating period. specular reflections from the underlying struc- The reflected beam at 2.45 GHz, at the har- ture. Diffuse reflections would cause each monics, as welI as at other frequencies gener- satellite to appear as bright as the planet ated by the rectenna structure itself, would Venus at its brightest phase (magnitude – 4.3). result in a complicated power spectrum which Specular reflections would occur near the wouId change in time as the rectenna ages. equinoxes just at local sunrise or sunset (i. e., The radiation patterns are expected to be 100 on the same meridian as the satelIite) and or broader and partially directive. A capability wouId cause a 330-km wide spot of Iight sever- to monitor and locate rectenna intermodula- al times brighter than the full Moon to sweep tion emissions is required to allow timely

structural repair to assure no interference with 4 ‘ P A E and M Stokes (eds ), “Workshop on Power sensitive terrestrial and aircraft equipment. Effects on Optical and Radio Astronomy, ” CON F-7905143 Optical and thermal emissions. The reference (DOE ], I “Apparent 1 of Solar Power Satellites, ” satellites would reflect sunlight in three major Power 1980, pp 175190 284 ● Solar Power Satellites

across the affected area in a few minutes. ● Heat radiation. Because an appreciable Glints from components of the satellite’s amount of the sunlight which is intercepted by structure are not expected to be as serious as the laser satellite would be absorbed and re- the diffuse or specular reflections and in any emitted as heat, the satellite, whether in CEO event, may be significantly reduced or elimi- or LEO, would be a diffuse infrared radiator nated by proper structural design. and would radiate some energy at microwave In addition to reflecting sunlight, the satel- frequencies as well. lite would also emit thermal radiation of an • Laser beam characteristics. The two major pres- estimated intensity of 6.3 X 10 6 watts per ent laser alternatives operate near 5 microns square meter at the Earth. The precise wave- (CO laser) or 10 microns (CO2 laser) infrared length peak depends on the details of the char- wavelengths. Because the beams are highly acteristics of the satellite’s components (e.g., directive, they would be only slightly observ- type of cell, type of antireflection coating, able in the infrared except for receivers placed etc. ) but would Iikely fall in the 5 to 10 micron very near the laser ground stations. Scattered band. The thermal radiation is expected to ex- light from the beam would be detectable in ceed SIightly current interference levels. the lower part of the atmosphere.

Laser Satellites Mirror Satellites As with the other characteristics of laser systems, Because the mirrors are designed to reflect the electromagnetic characteristics of the laser sun Iight only, their emissions wouId be only sIightly satellite are ill defined. However, the following altered from the original solar spectrum (i. e., they general radiation effects can be expected. Quan- wouIdn’t radiate appreciable infrared or micro- titative data will be available only after the wave radiation). Those emissions would be large, systems become more highly defined. however, for the ground base into which the sun- In general, laser systems would reflect sunlight light is directly reflected (i.e., the equivalent of one from the laser platform and from the relay mirrors Sun). in LEO and CEO, if any. I n addition, they wouId ● Terrestrial observers away from the ground radiate thermal energy, most probably in the 5 to site would see moving patches of light about 10 micron region of the infrared. They would also 0.5 min arc across surrounded by an aureole of be detectable as a thermal source of microwave scattered Iight. The precise apparent bright- power. ness of the mirrors wilI depend on a number of ● Reflected sunlight. The brightness of Iaser sat- factors, e.g., the orientation of the mirror with ellites at CEO or LEO would depend on the respect to the observer, the relative position of mode of power CoIIection and conversion (e. g., the Sun from both the mirror and the observer, photovoltaic or direct solar pumped) and the the albedo of the reverse side of the mirrors, overalI size of the satellite. OpticalIy, the most and the atmospheric conditions above the important differences are that the LEO satel- ground station. Low-intensity scattered sun- lite would be brighter and perceived as mov- light from aerosols and dust high in the ating slowly by terrestrial observers. mosphere would be observable at up to 150 Because they would be smaller than the ref- km from the ground station. erence system satellites, individually they would also be less bright. However, there will be more of them. (If laser satellites could be The Interaction Between Biological made to operate with the same efficiency as Systems and Electromagnetic Waves the microwave designs, five 1,000-MW or ten 500-MW satellites would be needed to equal Microwave radiation is a form of electromag- reference system capacity. ) Laser relay mirrors netic energy which is used in numerous commer- in LEO and GEO would contribute both sta- cial, industrial, military, and medical devices in- tionary and moving sources of light. However, cluding microwave ovens, radar, diathermy equip- because of their small size (several meters), ment, and sealing instruments. The microwave they are not expected to be readily visible band accounts for frequencies ranging from 300 from Earth. MHz to 300 GHz, Appendix D—Environment and Health ● 285

The extent and consequence of exposure of plete. The existence of frequency windows, biological systems to microwaves depends on the i.e., effects observed over one specific range following characteristics of the incident energy, of frequencies is not well-understood. the biological organism, and surrounding environ- ● Intensity of incident wave. –The energy car- ment:43 ried by an electromagnetic wave per unit area ● Frequency of electromagnetic radiation. — The and time is called its power density and is frequency of radiation is the number of com- measured in units of milIiwatts per square cen- plete oscillations per second of an electromag- timeter (mW/cm2). Heating or thermal effects netic wave. The energy of the radiation is are generally thought to occur at power den- directly proportional to the frequency. Al- sities greater than 10 mW/cm2. Effects at much though the frequency of microwaves is high, it lower power densities have been postulated is not high enough for the quanta to ionize, but the existence and consequence of “non- i.e., to eject an electron from a molecule or thermal” phenomena remains in dispute. Pow- atom; hence microwaves are called “nonioniz- er density windows have been observed ex- ing. ” The bioeffects of X-rays and other ioniz- perimentally in which bioeffects are noted ing radiation are known to be more severe only over a specific range of power densities than those resulting from the nonionizing por- and not above or below. tion of the spectrum. Recently, the microwave community has The frequency also determines the depth of adopted the specific absorption rate (SAR) as a penetration when an electromagnetic wave is measure of the energy absorbed by a biologi- incident on biological material. I n general, the cal organism. The SAR is expressed in units of lower the frequency, the greater the depth of milliwatts per gram (mW/gm). It is a function penetration. For example, infrared waves pen- of the power density and weight of the ir- etrate no deeper than human skin, whereas mi- radiated organism. While the SAR provides crowaves (which are lower in frequency) pen- more information about the bioeffects of etrate through the skin and fat and into human microwaves than it does of the power density muscle. 44 The relationship between frequency alone, it cannot be used to entirely predict the or wavelength (frequency is inversely propor- effects of exposure to microwaves. The SAR is tional to wavelength) and the size of the irradi- averaged over the entire body; it does not con- ated body is also important. Resonance (i. e., sider energy absorbed differentially in specific most efficient absorption) will occur when the body parts. It also does not account for possi- length of an organism measures approximately ble nonthermal effects. Furthermore, it does half of a wavelength of the incident elec- not measure the “biological effectiveness” of tromagnetic field. For example, the resonance a microwave, i.e., its ability to induce an effect frequency at which the absorption rate is max- which is dependent on parameters such as the imized for the male human body is on the relation between the frequency and size of order of 70 to 100 MHz, whereas the maximum subject or body part. absorption rate for rats occurs at 2.45 GHz.45 ● Duration of exposure. – For thermal effects, Thus, an electromagnetic wave may elicit a the length of exposure may influence the very different response from organisms of two body’s ability to cool. Heating resulting from different sizes (assuming that the amount of long duration exposure of high-intensity waves energy absorbed is the dominant determinant may overwhelm the natural cooling system. At of a biological response). lower power densities, i.e., “nonthermal” Understanding of the functional depend- levels, the cumulative or long-term effects are ence of bioeffects on frequency is not com- not known. ● Waveform. – It is thought that the biological ‘ ‘For a more detailed discussion of the biophysics of microwave inter- consequences of exposure to continuous wave actions with blologtcal systems, see S Baranskl and P Czelskl, i310/oglca/ radiation is usually less severe than from that Effects of Microwaves, Dowden, Hutchlnson and Ross, Inc , Pennsylvania, 1976 which is pulsed or modulated, although basic “R D Phllllps, et al , Comp//atlon and A$$e$\ment of Microwave BIo- appreciation of the mechanisms of interaction effects A Se/ect/ve Rev/ew of tfre L Iterature on the Blo/og)ca/ L ffectj of is lacking, Microwaves In Re/at/on to tfre $ate///te Power $y~tem ($P\), final report, ● DOE/NASA, May 1978 Subject characteristics. – Bioeffects are spe- “E Berman, “A Review of SPS-Related Microwaves on Reproduction cies-specific, primarily because the factors and Teratology”, I n The Flna / Proceedings of the $o/ar Power Sate///te Pro- gram Rev/ew, Apr 22-25, 1980, DOE/NASA report Conf -800491, July which determine energy absorption such as 1980 size, structure, body, insulation, and heat dis-

83-316 0 - 81 - 20 286 ● Solar Power Satellites

sipation, and adaptive mechanisms vary with SPS-Related Microwave Bioeffects species. The composition and geometry of bio- Experiments (conducted by DOE, EPA) logical matter also determine the depth of penetration and wave characteristics; tissue, In conjunction with the SPS DOE assessment, muscle, and fat each exhibit different dielec- three studies were initiated and managed by EPA.46 tric and conductive properties. Thus, without • Exposure of bees to 2.45 GHz at 3, 6, 9, 25 and adequate theories of interaction, extrapola- 50-mW/cm 2. No statistically significant effects tions from animal studies to human bioeffects on behavior, development, or navigation have are extremely difficult. The sex, age, and state been observed following short-term exposure. of health of an irradiated subject may also be Long-term exposures are planned and should an important factor, since size and suscep- clarify this possible effect. It has also been tibility to certain kinds of effects may differ proposed that tests of effects on bee naviga- with respect to these parameters. It also ap- tion be carried out in the absence of sunlight pears that electromagnetic radiation may act (which may possibly mask microwave induced synergistically with drugs. The differential ab- effects). sorption of energy may result in hotspots. This ● Immunology and hematology studies of small relatively increased energy deposition in cells, mammals exposed for short durations to about organs or parts of the body relative to its sur- 20 mW/cm2, 2.45 GHz microwaves. No effects roundings could lead to very specific biologi- have been reported so far. cal effects after exposure. ● Experiments testing the effects on the behav- The orientation of the organism with respect ioral and navigational capability of birds sub- to the electric field component of the wave is jected to acute and chronic exposures of 2.45 also important —the most energy is absorbed GHz fields. Some mortality has resulted from when the electric field is parallel to the long exposure to 130 to 160 mW/cm2 microwaves axis of the body. In animal experiments, phys- and has suggested that species and body ge- ical restraints or sedation might influence ometry determine tolerance levels. Generally, study results. Measurement devices such as no statistically significant effects have been implanted probes could also alter the field detected at power densities of 0.1 to 25 distribution. The prediction of bioeffects may mW/cm2. Some birds chronically exposed to also be complicated by movement of the sub- 25 mW/cm2 have exhibited an increase of ag- ject in the field which changes the absorbed gressive behavior, although the number of energy dosage and may result in modulation birds is statistically insignificant. of the field. The effects of whole body irradiation may Laser Bioeffects differ from partial body exposure. In addition, for either whole or partial body irradiation, Lasers are unique among light sources because smaller body parts could resonate if the fre- of their capacity to deliver an enormous amount of quency used was in resonance with that part energy to a very small area at a great distance.47 of the body. The primary biological consequence of this proper- ● Environment. –The humidity, temperature, ty is heating. However, nonthermal mechanisms and air circulation of the surrounding environment will affect the ability of a heated biologi- ‘“C H Dodge, Rapporteur, Workshop on Mechanisms Underlying Ef- cal entity to cool. Objects near the elec- fects of Long-Term, Low-Level, 2450 MHz Radlatlon on People, organized tromagnetic field could also enhance, reflect, by the National Research Council Committee on Satelllte Power Systems, absorb or distort it. For SPS, the effects of the Environmental Studies Board, National Academy of Sciences, ] uly 15-17, 1980 space environment on the biological response 4 ‘E- Kle IrI ‘ Hazards of the Laser,” Hosplta/ Practice, May 1967, pp to microwaves are not known. 48-5 J Appendix D—Environment and Health ● 287

have also been suggested.48 For example, photo- either, but is absorbed by the cornea and lens. Most

chemical reactions are thought to be responsible of the radiation from the C02 laser is absorbed in for damage of biological organisms exposed to the 7 nm tear layer of the cornea. 56 Continuous irra- ultraviolet lasers.49 High laser power densities may diances of the order of 10 W/cm2 could produce le- also cause injury from shockwaves or high electric sions within the blink refIex.57 Corneal damage may field gradients.50 Biological electromagnetic in- be reversible or repairable but severe damage may terference effects have also been proposed.51 result in permanent scarring, blurred vision, and Clearly, the mechanisms of interaction between opacities. 58 The lens is particularly susceptible to laser light and biological entities are not complete- injury because of its inability to eliminate damaged ly understood. Like microwaves, little is known celIs. Lenticular damage characterized by cata- about the cumulative or delayed effects of chronic racts or clouding may occur at irradiance levels exposure to low levels of laser light.52 In general, that do not produce corneal injury. For example, the higher the power and the shorter the period, the “glassblowers cataracts” are thought to result from greater the damage.53 The extent of the effect also chronic exposure to 0.08 to 0.4 W/cm2 infrared 59 depends markedly on the characteristics of the irradiation. Proposed thermal limits for pulsed C02 radiated biological material. Of primary impor- lasers range from 0.2 to 1.0 W/cm2, ’0 but this tance is a tissue’s absorptivity, reflectivity, water recommendation requires further study. content, and thermal conductivity. Effects on the skin from absorbed radiation may The organ of the body most sensitive to laser vary from mild erythema (sunburn) to blistering radiation is the eye. The ocular media of the human and/or charring. 61 The principal mechanisms of in- eye transmit light with wavelengths between 400 jury by infrared radiation are thermal and are a and 1,400 nm. 54 There are two transmission peaks in function of tissue reflectance, spectral depth of the near infrared at 1,100 and 1,300 nm. Light in the penetration, and the size of irradiated area. Since visible and near infrared spectrum is focused thermal burns are produced at temperatures higher towards the retina. The refraction of the laser beam than that which causes pain, in most present oc- by the ocular media amplifies the light intensity by cupational situations the pain can serve as warning. several orders of magnitude.55 As a result, in this A definite sensation of warmth is produced from 2 spectral region the retina can be damaged at radia- C02 lasers at 0.2 W/cm over an irradiated area tion levels which are far less than those which pro- only 1-cm diameter, or 0.01 W/cm2 for full body ex- duce corneal or skin damage. posure. 62 Heat stress should not be overlooked. For lasers that emit wavelengths outside of the More research is needed to determine the effects visible and near infrared range, the ocular effects of chronic or repeated exposures. are quite different. At ultraviolet wavelengths, for As was the case for exposure to microwaves, the example, light is absorbed primarily by the cornea, determination of laser thresholds and standards is which can be injured by photochemical reactions. exacerbated by problems of detection and meas- Infrared radiation is not focused on the retina urement, instrument sensitivity, dosimetry, inter- species and interfrequency extrapolation, and lack

‘“V T Tomberg, “Non-Thermal Blologlcal Effects of Laser Beams, ” of complete knowledge of physiological systems, Nature, VOI 204, Nov 28, 1964, pp 868-870 mechanisms of interaction, and synergistic effects. “Department of the Alr Force, Ffea/th ~azdrd~ Contro/ for Laser Radla- tlon, AFOSH Standard 161-10, May 30, 1980 ‘“U \ Army Environmental Hyglence Agency, Laser and Opt/ca/ ‘[)lbld Haiard~ Course Manua/, Aberdeen Proving Ground, Md , 8th ed , ]anuary ‘‘M Zaret, “Laser Appl Icatlon In the F Ield of Medlclne, ” ZAMP, VOI 16, 1979 1965, pp 178-79 ‘‘D H Sllney, K W Vorpahl, and D C Wlnburn, “Environmental “M L Wolbarsht and D H Sllney, ‘Needed More Data on Eye Health Hazards From High-Powered Infrared Laser Devices, ” Arch En- Damage, ” Laser Focus, December 1974, pp 11-13 v/ronmenta/ Hea/tfr, VOI 30, April 1975, pp 174-179 ‘‘Supra note 47 ‘“ Supra note 47 “W T Ham, et al , “The Eye Problem In Laser Safety, ” Arch En- ‘9 Supra note 55 v/ronmenta/ Hea/th, VOI 20, February 1970, pp 1 ;6-160 ““Suprd note 49 “D H Sllney and B C Fresler, “Evaluation of Optical Radlatlon “ Ibid Hazards, ” App/ied Opt/es, VOI 12, No 1, j anuar~ 1973, pp 1-24 ‘2 Supra note 55 288 ● Solar Power Satellites

Experiments also make clear that the extent of the of recovery following return from space.69 For SPS, superficial or immediate lesion is no gage of total however, the effects of periodic weightlessness damage. ’3 over a long time period need to be investigated. The exposure limit for continuous wave infrared Moreover, ameliorative measures suitable for a lasers as recommended by ANSI is 100 mW/cm2 for large number of people with broad physiological exposures over 10 seconds and for smalI spot sizes characteristics must be investigated .’” on the skin or eyes.64 A whole body irradiance limit Workers would be exposed to electric fields of 10 mW/cm2 has been suggested .65 It should be generated by the collection and transmission of stressed that the protection standards for repetitive large amounts of electricity across the solar panel and chronic exposures and for wavelengths outside and antenna, but effects of electric and magnetic the visible band are based on a considerable fields on biological systems are not well-under- amount of extrapolation. Data obtained from non- stood.71 Research is needed to determine the bio- Iaser sources, such as bright, small-source lamps effects of magnetic fields generated by satellite and high luminance extended sources cannot accu- electric currents, as well as to assess the effects of rately and wholly represent the effects of laser field absence over extended stays in orbit, as CEO radiation in determining injury thresholds for is largely outside of the Earth’s magnetic field. ultraviolet and infrared lasers directly. Some space workers could also be exposed to high levels of microwaves. The effects of microwaves in General Health and Safety of a space environment deserves special attention. It SPS Space Workers* is known, for example, that microwaves can work synergistically with ionizing radiation to increase The human body’s tolerance to acceleration the biological effectiveness of the latter. ” depends on the duration and magnitude of the Research would be required to determine bio- acceleration, the positioning of the body relative to effects and if possible, to develop suitable the accelerating force, the restraint and support exposure Iimits and protective clothing. systems of the spacecraft and the time spent in a Psychological impacts must also be assessed, weightless state. ” Research is needed to quantify especially since there is little information on large, effects as a function of these parameters and to mixed gender groups working in close confinement determine the tradeoffs between short duration, for prolonged periods. Studies should also consider high acceleration and longer duration, lower accel- the effects on workers’ families and friends and eration effects. Studies should also evaluate the possible mitigation measures such as careful work- tolerance in the population that may fly in space er selection, recreation faciIities, social manage- (since variation in individual response levels are ment, etc. great) and explore possible ways to reduce harmful Space workers could be prone to greater safety effects. ” risks than their terrestrial counterparts because of Weightlessness is known to induce a number of the possible awkwardness of working without grav- physiological responses such as decreased heart ity.73 Risks also stem from the high-voltage equip- rate, shifting of fluids to the upper body, decrease ment and handling of toxic materials. There is a of muscle mass and loss of bone minerals .68 Most danger that spacecraft charging could produce of the observed effects have been temporary; only electric shocks great enough to injure or kill bone calcium loss appears to require a long period workers, although this might be avoided by a ju- dicious choice of spacecraft material. Catastrophic

b* Supra note 47 CoIIisions with meteoroids or space debris are also ‘“American Natlona/ Standard for the Safe Use of Lasers, ANSI (R) possible, given SPS’s large size. Extravehicular Z136 1-1979, American National Standard Institute activity may also create hazards. “D H S1 Iney and D L Cono\,er, “Nonlonlzlng Radlatlon” In /rrdustr/a/ Errv/ronmenta/ Hea//h, L V Cralley and P R Atkins (eds ) (New York Academic Press, 1975), pp 157-172 *See text for discussion of Ionlzlng radlatlon effects — 6bEnvironmen/a/ Assessment for the Sate///te Power ‘5 y$tern Concept L)e- ‘}’lbld ve/opment and Eva/uatJon Program, DOE/E R-0069, August 1980 ‘(’lbld “lbld 7‘ Jupra note 66 “Program Assessment Report, Statement of F/nd/ng~, Satelllte Power ‘ Baranskl and P Czerskl, L310/oglca/ Effects of M/crowave~, Dowden, System Concept Development and Evaluation Program, DOE/E R-0085, Hut, hlnson and Ross, Pennsylvania, 1976 November 1980 7 ‘\upra note 66 Appendix E EXAMPLES OF INTERNATIONAL COOPERATION

Part 1 Iy by nations, the other by designated agencies (“signatories”), one per nation; 4) that Intelsat Intelsat was preceded by the formation of a would be restricted to providing services between domestic company, Comsat. In 1962 the Federal countries, not within countries; 5) the interim Government, after extensive debate over the prop- agreements would last 5 years, at which point per- er degree of Federal involvement, chartered Com- manent arrangements wouId be agreed on. sat Corp. to provide a commercial communications One immediate result was the refusal of the satellite system “in conjunction and cooperation Soviet Union and East Europe to participate. The with other countries . . which wilI serve the com- Soviets used only a miniscule amount of global munication needs of the United States and other communications traffic, some 1 percent, and countries, and which wilI contribute to world peace would not join an organization dominated by the and understanding.’” Comsat was not directly United States and West Europe. They began devel- owned or run by the Government; it issued shares oping their own domestic system (Molniya), which of voting public stock (which were immediately later formed the core of their international system, over-subscribed), with 50 percent of these reserved Intersputnik, covering the Soviet Union, East for “common carriers” —AT&T, ITT, Western Europe, Cuba, and Mongolia. Union, and others. The Board of Directors con- When the interim agreements were renegotiated, sisted of three Presidential appointees, six common from 1969 to 1971, the basic structure was retained. carrier representatives, and six elected at large. However, a number of changes were made, many However, although Comsat was not directly fi- of them designed to reduce U.S. dominance and to nanced by the Government, it received and con- increase the direct role of national governments.3 tinued to receive the benefit of extensive NASA- Comsat was phased-out as the manager, manage- sponsored development of communication satel- ment being turned over to a Director General, lites and launch-vehicles, free of charge–some responsible to a Board of Governors composed (in several billion dollars worth. (NASA research on 1979) of the 27 largest participants or groups of par- communications satellites was cut back under the ticipants, representing a total of 83 signatories. A Nixon administration but reemphasized in the new voting structure was established to prevent de Carter administration’s October 1978 White House facto U.S. veto power. The minimum participation Fact Sheet, largely as a result of increased competi- was lowered to 0.05 percent. AlI signatories and tion from Japan and Western Europe.) states parties were entitled to receive free, tech- Under its charter, Comsat was allowed to enter nical information generated by Intel sat contracts. directly into negotiations with foreign entities with Intel sat was allowed to provide services to domes- the supervision and assistance of the State Depart- tic and regional satellite groups. Net property in ment. In 1963, a U.S. negotiating team proposed a 1980 is valued at $663 mill ion, with $523 million of framework for an international telecommunica- that in the space segment proper. Return on invest- tions satellite organization: lntelsat. In a series of ment in 1979 was better than 14 percent.4 meetings details were agreed on: 1) that Comsat wouId be the consortium manager2 and majority Part 2 owner, with an initial 61 percent of the shares; 2) that ownership and utilization charges, as well as Like Intelsat, Inmarsat is a commercial, profit- voting, would be in proportion to the use of the making venture with a corporate structure and in- system by each participant, readjusted on an an- dependent legal personality. Comsat is the U.S. sig- nual basis, and that membership would be open to natory, holding the largest original share at 17 per- alI ITU member nations, with a minimum 15-percent; Great Britain is second with 12 percent, the cent share needed for representation and voting; 3) Soviet Union third with 11 percent. ’ Initial cap- there would be two levels of agreement, one direct- italization was set at $200 milIion. Because it could participate on a more equitable

“’Communlcatlon> Satellite Act of 19b2, In Space Law, Se/ected Ela$fc basis, the Soviet Union joined Inmarsat; one conse- Documents, Senate Committee on (’ommerce, Science, and Transport tlon, Dec 1978, p 523 !R IC hard Col lno, The /rite/sat De flnlt/ve Arrangements (Geneva Euro- ‘Joseph N Pelton, G/oba/ Comrnunlcatlons Sate//(te Po/Icy lnte/sat, pean Broadcasting Union, 1973), p 11-12 Po/ItIcs and funct~onallsm (Mt Airy, Md Lomond Books, 1974), p 76 ‘Intel}at Annual Report 1980 Intelsat, Washington, D C , p 21 (p 55) “ Operating Agreement on Inmarsat,” 1976, In Space Law, p 445

289 290 Ž Solar power Satellites quence was Soviet insistence that nongovernmen- European bids were higher than U.S. ones, it was tal signatories —e.g., Comsat and Japan’s Kokusai argued that these were necessary to develop com- Denshin, Ltd.—be guaranteed by their govern- petition for the United States, and that it was unfair ments. It has been pointed out that the Soviet for U.S. firms to reap all the financial benefits. Union “is disinclined to enter mixed organizations Over time, U.S. firms began to subcontract exten- involving states and private enterprise, ” preferring sively abroad in an effort to reduce criticism of U.S. to deal only with other states. G contract dominance. In the permanent agreement, procurement pol- Part 3 icy was established with emphasis on the “best combination of quality, price and most favorable The vast majority of Intelsat signatories were delivery time.” However, in the event of equivalent government communications agencies. Only in a bids “the contract shall be awarded so as to stim- few instances, such as Comsat for the United ulate in the interests of Intelsat, worldwide com- States, and Interspazio for Italy, were the signa- petition” (art. 13).8 This loophole gave Intelsat the tories separate corporate entities designed for com- option of allocating contracts on a geographic munication satellite operations. One result was a basis as long as it determined that they were conflict of interest within agencies that were in- roughly equivalent. In recent years, approximately volved in other communication systems, especialIy 15 percent of the dollar value of Intel sat procure- underwater cables. Differences of opinion also de- ment contracts has been spent outside the United veloped between Comsat, which wanted to expand States 9 Intel sat into as many other areas, including domestic communications, as possible; and agencies that Part 4 wanted Intelsat’s scope restricted to international telephone and television relay. Unlike ESRO, which had its own facilities, ELDO At the beginning, Comsat, with headquarters in was entirely a coordinating body for separate na- Washington, D. C., was the managing agency; Amer- tional efforts. The initial planning called for a ican launchers were used through NASA; and the British first stage, a French second stage, a German satellites themselves were built by U.S. firms — third stage, and so on. Launches were to take place (Hughes for Intelsat I, II, IV, and IV-A; TRW for ln- in Woomera, Australia. The major countries had telsat III; Ford Aerospace for Intel sat V). The initial widely differing interests. France was interested in agreement was structured in such a way that U.S. an across-the-board capability to compete with the participation could never be less than 50.6 per- superpowers and demonstrate French independ- cent. 7 ence and prestige, an aim directly connected with Initially, participation by lesser developed coun- French military programs in nuclear submarines in numbers, tensions developed between LDCs, and intermediate range ballistic missiles. France Europeans, and the United States over the distribu- feared that the United States would not provide tion of benefits. One issue concerned the relative launch services for French military satellites or for investment between satelIites and ground stations. programs that promised to compete commercially Since users were responsible for building their own with the United States. Earth stations, LDCs and others with fewer re- Germany was more interested in private com- sources and lower usage urged Intelsat to increase mercial ventures, and was much more willing to the size and complexity of the satellite component cooperate with the United States. Great Britain, in order to reduce Earth-station costs. faced by the mid-1960’s with severe financial con- As European aerospace capabilities matured, straints and enjoying a close relationship with the members began to lobby for larger shares of In- United States, preferred less expensive programs in telsat R&D and procurement contracts. Even when telecommunications and remote sensing.

““ Intel sat Organ lzatlon Agreement, ” 1973, In Space Law, p 214 ‘Stephen Doyle, “lnmarsat Origins and Structure, ” 1976 “Conversation with ]ohn Donahue, Intelsat procurement office, Oc- ‘Pelton, op cit , p 58 tobel 1980 I j j j j j j j j ACRONYMS, ABBREVIATIONS, j j AND GLOSSARY j j j j j j j j j j j j j j j j j j j j j j j j j j j j j j j j Acronyms and Abbreviations

AF – audio frequency GEO – geostationary orbit AlAA – American Institute of Aeronautics and HEAO-C – High Energy Astronomical Astronautics Observatory-C ANSI — American National Standards Institute HEL – high-energy laser A-sat — antisatellite HEW – Department of Health, Education and Aramco – Arabian-American Oil Co. Welfare BBB — blood brain barrier HF – high frequency BRH – Bureau of Radiological Health HFAL – high frequency auditory limit Btu — British thermal unit HLLV – heavy-lift launch vehicle bui – brain uptake index HRP – horseradish peroxidase CB — citizens’ band HVTL – high-voltage” transmission line CEP – Citizen’s Energy Project Hz — hertz: a unit of frequency equal to — centimeter one cycle per second CMEA — Council of Mutual Economic HZE — high-atomic-number, high-energy Assistance (Comecon) (East Europe, particles Soviet Union, Cuba) IAF — International Astronautical Federation CNS – central nervous system ICBM — intercontinental ballistic missile CONAES – Committee on Nuclear and IEA — International Energy Agency Alternative Energy Sources (National IEEE — Institute of Electrical and Electronics Academy of Sciences) Engineers COPUOS – Committee on Peaceful Uses of Outer ISM — industrial, scientific, and medical Space (United Nations) ITU — International Telecommunication COTV — cargo orbital transfer vehicle Union Comsat – Communications Satellite Corp. kg kilogram cpm — counts per minute km — kilometer CW — continuous wave kw kilowatt (103 watts) dB – decibels laser — light amplification by stimulated dc – direct current emission of radiation DOD — Department of Defense LEO – low-Earth orbit DOE – Department of Energy LMFBR – liquid metal fast breeder reactor DMSO – dimethyl sulfoxide LORAN – long-range navigation EDL — electric discharge laser MHz – Megahertz (106 cycles per second) EEG — electroencephalogram m MPTS — microwave power transmission system EKG — electrocardiogram MW — megawatt (10’ watts) ELDO – European Space Vehicle Launcher mW/cm 2 — milliwatts per square centimeter Development Organization NAS — National Academy of Sciences ELF — extremely low frequency NASA – National Aeronautics and Space EMF — electromagnetic fields Administration EMP — electromagnetic pulse NATO — North Atlantic Treaty Organization EMR — electromagnetic radiation NBS – National Bureau of Standards EOTV — electric orbital transfer vehicle NIEMR — nonionizing electromagnetic radiation EPA — Environmental Protection Agency NIOSH – National Institute of Occupational ER — evoked response Safety and Health ESA – European Space Agency NRDC – Natural Resources Defense Council ESRO – European Space Research OECD – Organization for Economic Organization Cooperation and Development FCC — Federal Communications Commission (United States, Canada, Japan, West FDA — Food and Drug Administration Europe) FEL — free electron laser OMEGA — generic name for long-range CDL — gas discharge laser navigation GNP – Gross National Product OPEC – Organization of Petroleum Exporting GHz – gigahertz (109 cycles per second) Countries Gw – gigawatt (109 watts)

293 294 • Solar Power SateLLites

OSHA – Occupational Safety and Health SAM — surface to air missile Administration SAR — specific absorption rate OTA – Office of Technology Assessment SEPS — solar electric propulsion system PLV – personnel launch vehicle SPS — solar power satellite POTV – personnel orbital transfer vehicle SRBC — sheep red blood cells prf — pulse repetition frequencies SSTO — single stage to orbit space vehicle Q – Quad (quadrillion BTUS) STS — space transportation system Qe – Quad, electric t — metric ton (tonne); 1,000 kg R&D — research and development TVA – Tennessee Valley Authority rem – Roentgen equivalent man, the UHF — ultra high frequency quantity of ionizing radiation whose VER — visually evoked electrocortial biological effect is equal to that response produced by one roentgen of X-rays VHF — very high frequency RFP — radiofrequency radiation WHO — World Health Organization Glossary

Ablate—to remove by cutting, erosion, melting, heredity and variation by the methods of both evaporation, or vaporization. cytology and genetics. Aerosol—a suspension of insoluble particles in a Cytology– a branch of biology dealing with the gas. structure, function, multiplication, pathology, Albedo–the fraction of incident light or electro- and Iife history of cells. magnetic radiation that is reflected by a surface Decible– a unit for expressing the ratio of two or body. amounts of electric or acoustic signal power Ambient—the natural condition of an environmen- equal to 10 times the common logarithm of this tal factor. ratio. A ratio of 10 is 10 dB, a ratio of 100 is 20 Amplitude–the maximum departure of the value dB, a ratio of 1,000 is 30 dB, etc. of an alternating wave from the average value. Diffuse reflection— reflection of a beam incident on Artifact— a product of artificial character due to an a surface over a wide range of angles. extraneous agent. Dosimeter– a device for measuring doses of radio- Attenuation– a reduction in amplitude of electro- activity. magnetic energy. Ecliptic–the circle formed by the apparent yearly Beam width–the angular width of a beam of radia- path of the Sun through the heavens; inclined tion, measured between the directions in which by approximately 23.50 to the celestial equator. the power intensity is a specified fraction, usu- Electromagnetic energy– energy in the entire range alIy one-half, of the maximum. of wavelengths or frequencies of electromag- Bias current–the electric current applied to a netic radiation extending from gamma rays to device (e.g., a transistor) to establish a reference the longest radio waves and including visible level for operation. light. Biota—the plants and animals of a region. Electron— a subatomic particle with a negative Brayton cycle— a method of driving a turbine in electrical charge. which a gas is compressed and heated. The Endocrinology– a science dealing with the endo- most familiar use is for aircraft gas turbine crine glands, which produce secretions that are engines. An alternative to the Rankine cycle. distributed in the body by way of the blood- Bremsstrablung radiation– radiation from charged stream. particles that are decelerated in a magnetic Energy dose– the quantity of electromagnetic field. energy (in joules) that is imparted per unit of British thermal unit-quantity of heat needed to mass to a biological body. raise one pound of water one degree Fahrenheit Energy dose rate— the amount of electromagnetic at or near 39.2 ‘F. energy that is imparted per unit of mass and per Circadian–pertaining to events that occur at ap- unit of time to a biological body. proximately 24-hr intervals, such as certain bio- Epidemiology-a branch of medical science that logical rhythms. deals with the incidence, distribution, and con- Cloud condensation nuclei (CCN)–particles on trol of disease in a population. which water vapor condenses to form water Extended source—an extended source of radiation droplets, that in turn form clouds and fogs. that can be resolved into a geometrical image Convection-circulatory motion that occurs in the in contrast with a point source of radiation, that atmosphere due to nonuniformity in tempera- cannot be resolved into a geometrical image; a ture and density, and the action of gravity. source that subtends an angle greater than one Cortical tissues–tissue from the outer layer of gray arc min. matter of the brain. Exosphere–the outer fringe region of Earth’s at- Cosmic ray–atomic nuclei of heterogeneous, ex- mosphere. tremely penetrating character that enter the Field intensity–the magnitude of the electric field Earth’s atmosphere from outer space at speeds in volts per meter or the magnitude of the mag- approaching that of Iight. netic field in amperes per meter. Coupling–the mechanism by which electromag- Flux–the rate of transfer of particles or energy netic energy is delivered to a system or device. across a given surface. CW laser–continuous wave laser, as distinguished Frequency—the number of complete oscillations from a pulsed laser. A laser emitting for a peri- per second of an electromagnetic wave, meas- od in excess of 0.25 second. ured in hertz (Hz). One hertz equals one cycle Cytogenetics– a branch of biology that studies per second.

295 296 ● Solar Power Satellites

Geostationary Earth orbit (GEO)– the equatorial or- Kapton– Iightweight, tough plastic film. bit at which a satellite takes 24 hr to circle the Klystron— an electron tube used to generate and Earth so that it is stationary as viewed from amplify microwave current. Earth; altitude approximately 36,000 km. Laser– a device for generating coherent light radia- Geosynchronous Earth orbit–the orbit at which a tion. satelIite takes 24 hr to circle Earth. (The satelIite Low-Earth orbit (LEO) –altitude approximately 500 may or may not appear to be stationary above a km. point on Earth.) Luminance–brightness on a light source, equal to Harmonic frequency– a component frequency of an luminous flux per unit solid angle emitted per electromagnetic wave that is a multiple of the unit area of the source. fundamental frequency. Magnetron— a magneticalIy control led tube used Heliostat– a mirror device arranged to follow the to generate and amplify microwave radiation; Sun as it moves through the sky and to reflect the power sources for microwave ovens. the Sun’s rays on a stationary collector. Magnetosphere– a region of Earth’s outer atmos- Hematology-a branch of biology that deals with phere in which electrically charged particles the blood and blood-forming organs. are trapped and their behavior dominated by Heavy-lift launch vehicle (HLLV)– a proposed launch Earth’s magnetic field. vehicle used to transport large masses of ma- Mass driver– an apparatus for accelerating material terial from Earth to low- Earth orbit. in an electromagnetic field. Illuminance– irradiance; rate of energy per solid Mesoscale–on or relating to a meteorological phe- angle measured at a given point. nomenon approximately 1 to 100 km in horizon- Immunology— a science that deals with disease re- tal extent. sistance and its causes. Mesosphere– a layer of the atmosphere extending Intermodulation –the mixing of the components of from the top of the stratosphere to an altitude a complex wave with each other in a nonlinear of about 80 km. circuit. The result is that waves are produced at Microwave– a comparatively short electromag- frequencies related to the sums and differences netic wave, especialIy one between 100 cm and of the frequencies of the components of the 1 cm in wavelength or, equivalently, between original waves. 0.3 and 30 GHz ‘in frequency. Intrabeam viewing– viewing the laser source from Modulation–when a continuous series of waves of within the beam. The beam may either be direct electromagnetic energy is modified by pulsing, or specularly refIected. or by varying its amplitude, frequency, or Ion—an atom or group of atoms that carries a phase, the waves are said, respectively, to be positive or negative electrical charge as a result pulse-, amplitude-, frequency-, or phase-modu- of having lost or gained one or more electrons. lated. In order to convey information by radi- Ionizing radiation– radiation capable of producing ating electromagnetic energy, it must be modu- ions by adding electrons to, or removing elec- lated, trons from, an electrically neutral atom, group Morphology-a branch of biology that deals with of atoms, or molecule. the form and structure of animals and plants. Ionosphere—the part of Earth’s atmosphere begin- Multibiotic– having or consisting of many plants ning at an altitude of about 5 km extending and and animals. outward 500 km or more, containing free elec- Multipath radiation— in contrast with a so-called trically charged particles by means of which plane wave, that flows in a straight line through radio waves are reflected great distances space, an area or volume where electromag- around the Earth. netic waves arrive from different directions Irradiance (E)– radiant fIux density arriving at given because of reflection or multiple sources is said surface in units of watts-per-square-centimeter to be the site of multipath radiation. (W/cm2); illuminance (as measured by a detec- Neuroendocrine-of, relating to, or being a hormo- tor). nal substance that influences the activity of Joule (J)– unit of energy (1 watt-see) under the inter- nerves. national system. As a thermal unit, 1 joule Neutral particles– molecules, atoms, or subatomic equals 0.239 calories. Since the calorie is de- particles that are not electrically charged. fined as the energy required to heat 1 gram of Neutron–an uncharged elementary particle that water from 40 to 50 C, 4.184 joules is the has a mass nearly equal to that of the proton equivalent of one calorie. Glossary ● 297

and is present in all known atomic nuclei except Propagation —the transmission of electromagnetic the hydrogen nucleus. wave energy from one point to another. Noctilucent cloud— a luminous thin cloud seen at Proton– an elementary particle that is identical night at a height of about 80 km. with the nucleus of the hydrogen atom, that Nonionizing radiation— radiation of too low an ener- along with neutrons is a constituent of all other gy to expel an electron from a molecule or atomic nuclei, that carries a positive charge nu- atom. mericalIy equal to the charge of an electron. Ohmic heating-a heating mechanism in a plasma Pulsed laser– a laser that delivers its energy in short or other conducting medium. The free electrons pulses, as distinct from a CW laser; a laser in the medium are accelerated by an applied which emits for less than 0.25s. electric field and give up kinetic energy by col- Radiation pressure– all propagating electro- lision with other particles. magnetic waves exert a very sIight pressure on Phase—the measure of the progression of a peri- an absorbing object. odic wave in time or space from a chosen in- Rankine cycle– a Iiquid gas cycle used often for stant or position. steam turbines. A working fluid is heated until it Phased array– an array of antennas that is aimed as expands and drives a turbine. a group by adjusting the phase of the signal it Rectenna– a coined term for the SPS reference sys- sends or receives. tem receiving antenna that also converts the Photoionization– ionization (as in the ionosphere) microwave power to direct-current electricity. resulting from CoIIision of a molecule or atom Rectification-the conversion of an alternating cur- with a proton. rent to direct current. Photoklystron — a device for directly converting visi- Refraction– a deflection from a straight path under- ble light to microwave radiation. gone by a wave in passing obliquely from one Photon— a quantum of radiant energy. medium into another in which its velocity is dif- Photoperiod – the interval in a 24-hr period during ferent. which a plant is exposed to Iight, Root-mean-square—for an alternating voltage, cur- Photovoltaic cell– a cell composed of materials rent, or field quantity: the square root of the that generate electricity when exposed to light. mean of the square of the quantity during a Plasma–a collection of charged particles exhibit- complete cycle. ing some properties of a gas but differing from a Scattered power– power that is reflected or dis- gas by being a good conductor of electricity persed as the result of an obstruction in the and by being affected by a magnetic field. path of the primary power flow. Polarization–the electric (E) and magnetic (H) fields Side lobe— refers to power radiated from an anten- that comprise a propagating electromagnetic na in a direction other than the desired direc- wave may be fixed in relation to Earth’s hori- tion of transmission. zon, or they may rotate. By convention, the vec- Slipring–a metal ring to conduct current in or out tor of the E field is related to Earth’s horizon: if of a rotating member of a machine. the two are perpendicular, the wave is said to Solar flare– an explosion on the Sun which gener- be vertically polarized; if parallel, horizontally ates fast elementary particles. polarized. When the E and H fields are continu- Solar wind–a stream of particles generated by a ously rotating with respect to the horizon, the solarfIare. wave is said to be elIipticalIy polarized. Solid-state amplifier– an amplifier whose operation Power–the quantity of energy per unit of time that depends on a combination of electrical effects is generated, transferred, or dissipated. The unit within solids, e.g., a transisterized amplifier for of power, the watt (W), is defined as one joule electromagnetic waves. per second (j/s). Specific absorption rate (SAR)–the quantity of elec- Power density-the quantity of electromagnetic en- tromagnetic energy that is absorbed by a body ergy that flows through a given area per unit of per unit of mass during each second of time; ex- time. Formally, power density is specified in pressed formally in watts per kilogram (W/kg); watts per square meter (W/m2), but by tradition often, informally as milliwatts or watts per in biological effects studies it is usually ex- gram (m W/g or W/g). “Specific absorption rate” pressed in milliwatts per square centimeter is being considered by the National Council on (mW/cm 2). Radiation Protection and Measurements as the 298 • Solar Power Satellites

official nomenclature for expressing the dose Symptomatology– a branch of medical science con- rate of radio-frequency electromagnetic radia- cerned with symptoms of diseases. tions. Synonymous with energy dose rate. Teratology-the study of malformation or serious Specular or regular reflection– a mirror-like reflec- deviations from the normal development of tion. fetuses. Spurious power or frequency–electromagnetic en- Thermosphere–the part of Earth’s atmosphere that ergy produced at frequencies that are not easily begins about 80 km above Earth’s surface, ex- related to a specified operating frequency. tends to outer space, and is characterized by Stratosphere– an upper portion of the atmosphere steadily increasing temperature with height. above approximately 10 km (depending on lati- Troposphere– the portion of the atmosphere below tude, season, and weather) and in which tem- the stratosphere, which extends outward about perature changes little with changing attitude 15 km from Earth’s surface, and in which tem- and clouds of water are rare. perature generally decreases rapidly with Sun-synchronous orbit– a near polar orbit which altitude. keeps the satellite in full sunlight all the time Van Allen belt— a belt of intense ionizing radiation while Earth rotates beneath it. that surrounds Earth in the outer atmosphere. Susceptibility—the sensitivity of an electromagnetic Wave guide– a device for transmitting and guiding receiver to undesired electromagnetic waves radio-frequency waves that may resuIt in interference. o