Volume I Solar Power Satellite Phase 1, Final Report Executive Summary System Definition Study D?80-25037-1 mm!I!w!i!i GENERAL @ EL Arthur D Little Inc (NASA-CR-160370) SOLAR POUER SLTELLITE Soh Power Satellite System Detinition Study Conducted for the NASA Johnson Space Center Under Contract NAS9-15636 Vdutne I PHASE I, FIK.4L REPORT Executive Summary DISe25037-1 Approved By: A@!%Ak-\ G. R. Woodcock Study Manager Boeing Aerospace Company Ballistic Missiles and Space Division P.O. Box 3999 Seattle. Washi~:gton 98! 24 1.0 INTRODUCIX)N AND BACKGROUND 1.1 History Solar power has long been recognized as an ideal source of energy for mankind. it is naturdly available and plentiful. does not disturb the envi- ronment. e.g.. by creation of wastes. and is itself free. About ten years ago. a way of utilizing solar energy to generate electricity on a 24-hour continuous basis was proposed by Peter Glaser of A. I). Little. His proposal w7as to place the solar - . - collectors in space. where they can collect sunlight continuously. can readily he ainied at the sun. and Figure 1. Solar PowSatdlites: The Pnkiple where very large cwllector areas wn be obtained with relatively little investment in mateial through the NASA Lewis Research Center to inves- resources. Ener~collected by these solar power tigate basic technical feasibility of the SPS concept. sritrllites (SPS's) woitld be tra~~smittedto Earth by The conclusions of that study were that the system electromagneti~ ,ncrlns. The origins1 Glawr pro- is technically feasible and could provide baseload posal. and rnost of the subsrqucnt studies. have electricity from solar powcr for use on Earth. assunled tile us of radio frequency s! stems in the Additional studies and experiments. partly funded microwsve frt.quenc! range. Recently. the possibil- by NASA over the period 1973 to 1975. estab- ity of laser br-aming has also bee11 r~.~opnized. lished the feasibility of efficient enersy transmis- sion at microwave frequencies. In 1975 a demon- The solar power satellite principle is illus- str~tionconducted at JPL trinsmitted more than trated in tipurr. I. In a geostationary orbit 36.000 30 kilowatts over a distance greater than a mile brn above tlie Earth's equator. ezch SPS would be with a reception and conversion efliciency of 81 illuminated by sunlight over 90'; of t!ie time and percent. in contirii~oi~slinc-of-sight contrict with its ground receiving starion. Electrical power produced on the In the 1975 to 1977 time period. NASA satellite by photovoltaic or heat engine conversion conducted a technical assessment of SPS and began of the sunlisht woi~ldbe converted to electrornag- inhouse studies at the Johnson and Marshall Space netic enerpy at high efficiency. ancl formed into a Centers. The Department of Energy conducted its narrow heam precisely sinied at the SPS pround own assessment: SPS was discussed in congressional stations. Tlic ground station receiving antennas hearing. These activities led to development of an would reconvert the energy into electricity for dis- SPS Development and Evaluation Progiarn Plan tribution. Solar pcwer satellites are intended to jointly sponsored by DOE and NASA. The princi- serve as producers of baseload electricity for utility pal niilestones irr this plan are: service. SPS's are seen not as .I si~bstitutefor other solar energy options. b::t JS 3 conlplenirnt that Reference System Definition Report. Oct. 1978 would allow solar rner$y to more co~iiplrtelyserve (Complete) humaniry s cncrgy needs. Preliminary Program Recommendations. May 197q Updated Program Recommendations. Jan. 1980 Dr. Glascr's original proposal W-:IS published Final Program Recommendati~ns,June 1980 in 1968 in Science magazine. In 197 1 and 1973 a small contractor study tea111 was formed including (Also during thi.: period. NASA-funded Arthur D. Little, Grumman, Raytheon and Spec- space transportation system studies indicated that trolab. This tearn was awr~rdcd ;I study contract the high traffic volumes required to support an SPS program could lead to cost reductions far below reductions in photovoltaics mass production those projected for the space shuttle. The potential might not be achieved.) The silicon photovol- for such cost reductions was seen as significant to taic system offers less risk with a more mature the economic practicality of SPS.) technology hut an energy conversion system roughly 40 percent gore massive tlldi galliun~ As 3 result, plans were for~llulated by arsenide. NASA to conduct solar power satellite system defmition studies in 1977 in order tc support the 2. Analyses c,f the power transmission system fust milestone of the DOEINASA evaluation plan. confurned the basic feasibility indicated by These would increase by roughly an onier of mag the earlier studies and detailed microwave link nitude the degree of depth of design and cost def~ error analysis confirmed attainability of ade- nition for SPS systems. One such study was quate efficiencies. Integrated power transmis- awarded to Boeing through the Johnson Space sion system conceptual designs were devel- Center; the other study was awarded to Rockwell oped ~vnsideringRF. electrical, mechanical, through the Marshall Space Flight Center. These and thermal factors. studies crea trd reference system designs including the solar power satellites. ground receiving stations, 3. Space transportation systems were designed space transportation systems, space construction to accomplish the SPS transportation opera- systems and other support systems. The results tions at acceptabie cost. indicated that SPS's could be built by the year 2000 with a likelihood of economic benefit. The 4. Space construction approaches and construc- principal !indings of these studies might be summa- tion base designs were developed for construe rized as follows: tion of 10,000 megawatt SPS's in geosynchro- nous orbit at a rate of approximately I per I. Examination of energy conversivri options led year. to a preference for silicon photovoltaicx in the Boeing study. and gallium arsenide photovol- nie principal system elements from that taics in the Rockwell study. (Both studies sug- study were the point of departure for the current gested thermal engine SPS designs as a hedge study. The preferred SPS defined by Boeing is illus- agai7i.t the possibility that expected cost trated in figure 2. -- 44-lktEU*NTyB*V USTRMIOMIV @)1PMLMIV RRIfJO LENGTH Figure 2. Reference Photovoltaic System Description 1.2 Objectives 4. Define the most economically prudent path to minimizing these uncertainties to the point The overall intent of the systems definition that confident decisions can be made to pro- studies, past and present, may be summarized as ceed or not to proceed with development of fdows: this energy system. 1. Assess the technical feasibility of solar power The specific objectives of the present study satellites based on forecasts of technic. cap* are: bility in the various applicable technologies. Select the most appropriate technological (1) to verify, maintain and update the presently- paths leading to the most environmentally defined elements of the system, benign and economically practical systems. (2) complete the definition of the total system. Defme the areas of high leverage research. and (3) prepare a series of phns required for technol- 2. Define the characteristics of SPS systems that ogy advancement and SPS program may be derived if a development were to pro- implementation. ceed. Awss performance, cost. operational characteristics. reliability, and the suitability Phase I of the present study. reported here- of SPS's ss power generators for typical com- with, has concentrated on the first two objectives. mercial electricity grids. Phase 11 will emphasize end-toend operations analyses and the third objective. These objectives 3. Assess the uncertainties inherent in the sys- and the timing of the study are designed to support tem characteristics forecasts, based on tech- the NASA program recommendations in fulfill- nological unczrtrtinties, on cost estimating ment of the DOEINASA evaluation plan. uncertainties, and on uncertainties that arise from incompleteness in the data base. 2.0 STUDY APPROACH AND STUDY TEAM The JSCIBoeing and MSFC/Rockwell SPS NASA in developing the reference system report, system definition studies of 1977 and early 1978 beginning with a thorough critique of the JSC/ proceeded largely independently of one another Boeing reference system, followed by analyses of and developed system concepts with a number of options and critique items. The reference design significant differences. NASA then developed a ref- was updated at the end of Phase I. The overall erence SPS system description based on NASA schedule is shown in figure 3. inhouse studies as well as on Boeing and Rockwell contract results. The Study Contract Team included Boeing as prime contractor and General Electric, Grum- The present study is divided into two man, Arthur D. Little, and TRW as subcontractors. phases; the first lasted 7 months and the second Principal task areas and the study team leaders for will last 9 months. Phase I accomplisheci additional each contractor are shown in figure 4. analyses of the options and issues identified by U Figure 4. Study Conmt Team Organization (?%a= I Tasks Shown) Figure 3. Study Plan Overview 3.0 STUDY RESULTS The presecltation of study results in this be built and tested to verify annealability as executive sumniary has been grouped under three well as survivability of the rest of the array major headings: