DOCSLIB.ORG

Orbital Slots for Everyone?

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Orbital Slots for Everyone? CENTER FOR SPACE POLICY AND STRATEGY MARCH 2017 ORBITAL SLOTS FOR EVERYONE? JOSEPH W. GANGESTAD THE AEROSPACE CORPORATION © 2017 The Aerospace Corporation. All trademarks, service marks, and trade names contained herein are the property of their respective owners. Approved for public release; distribution unlimited. OTR201700473 JOSEPH W. GANGESTAD Joseph W. Gangestad, Ph.D., is an expert in orbital mechanics and space-system architectures at The Aerospace Corporation. In addition to publishing several scholarly journal articles in the field of astrodynamics, he authored the articles on “Celestial Mechanics” and “Orbital Motion” for the McGraw-Hill Encyclopedia of Science and Technology. He is also the author of Good Grad! A Practical Guide to Graduate School in the Sciences and Engineering. ABOUT THE CENTER FOR SPACE POLICY AND STRATEGY The Center for Space Policy and Strategy is a specialized research branch within The Aerospace Corporation, a nonprofit organization that operates a federally funded research and development center providing objective technical analysis for programs of national significance. Established in 2000 as a Center of Excellence for civil, commercial, and national security space and technology policy, the Center examines issues at the intersection of technology and policy and provides nonpartisan research for national decisionmakers. Contact us at www.aerospace.org/policy or [email protected] Foreword “New Space” entrepreneurs propose constellations that number in the thousands of satellites, and in the rapidly evolving space industry, they may very well succeed. But constellations of this size bring greater risk for collisions and the creation of debris, and no organization is responsible for assessing how they may impact the broader space community. In a future world of mega- constellations, is the unregulated status quo for orbit selection a sustainable path? The History of Regulating Orbits With unfettered access to nearly any place in space, Geosynchronous Earth orbit (GEO) has long been rec- some orbits have become popular and crowded, such ognized as prime—and scarce—real estate. Starting as as sun-synchronous orbits in LEO, which provide a a measure for spectrum management, the international base for weather monitoring and Earth observation. community agreed in the 1960s to regulate the assign- Satellites in these orbits suffer from substantially more ment of slots in the GEO belt through the International day-to-day collision risk, which also elevates the long- Telecommunications Union (ITU). Today, any compa- term risk to the overall space environment. ny or nation planning to launch a satellite to GEO must The Future Population in Space apply to the ITU for an orbital slot, and popular regions over North America, Europe, and eastern Asia have be- The traditional space industry is growing at a sober come so congested that few or no slots are left for new pace, looking to loft one, two, or a handful of large, entrants to the market. high-capacity satellites at a time. The operator of to- day’s largest private constellation, Iridium Satellite With most of the regulatory focus on GEOs, orbital as- Communications, looks only to replenish its current signments for low Earth orbit (LEO), medium Earth architecture, which numbers in the tens of satellites. orbit (MEO), and highly eccentric orbits (HEOs) have been left unregulated. In the United States, the Federal “New Space” entrepreneurs, however, are determined Communications Commission (FCC) requires any op- to disrupt the communications and imaging industries, erator seeking a com- setting their sights on munications license offering continuous, also to submit a report Imagine having a collision as ubiquitous space-based verifying that a satellite services, which demand satisfies internation- disruptive as the 2009 Iridium- massive constellations. ally accepted debris- Cosmos collision every year… Since late 2016, no few- mitigation require- er than five well-fund- ments, but the FCC is ed companies from agnostic to the orbit the United States and itself. Spectrum management motivated some bilateral abroad have proposed and trilateral coordination on navigation constellations mega-constellations for global coverage: OneWeb plans in MEO (e.g., GPS vs. Russia’s GLONASS vs. Europe’s to launch up to 1,320 satellites to LEO and 720 to MEO; Galileo, all in the same orbit regime), but these interac- Boeing proposes launching up to 2,956 satellites to LEO; tions occurred at the nation-state level. SpaceX intends to provide broadband communications 2 with 4,425 satellites for Ka-band and another 7,518-satellite constellation for V-band; Telesat Canada seeks to field 2017 2025? two constellations each of 117 satel- lites; and Planet—recently merged with Terra Bella—will have no fewer than 67 satellites in LEO to image the entire surface of the Earth every day. By the mid-2020s, more than 15,000 new satellites could be in space, with their orbits selected myopically with- in the context of their own needs and with no consideration for the impact on the global space enterprise. Figure 1: The crowded space environment today, showing all tracked objects, and what it may When the System Breaks look like a decade from now, with proposed mega-constellations. This unprecedented proliferation of ◆ Option 1: Do Nothing. Although technical analysis satellites, particularly in LEO, will bring with it dra- paints a grim picture in terms of debris risk and col- matic jumps in the risk of collision, debris generation lisions, the proposed mega-constellations are borne and its cascading effects for future collisions, and the from a vibrant entrepreneurial spirit in the space in- number of close-approach warnings for active satellites. dustry that hasn’t been seen since the dawn of the Aerospace recently performed an analysis1 looking at Space Age. Expanding the regulatory regime to all the implications for the global debris environment if orbits could have a stifling effect on innovation or just a couple of these mega-constellations are realized. limit market access only to large entities that have Its findings suggest that by the late 2020s and beyond, the resources and connections to ensure a smooth space could be far less hospitable than today: regulatory process. By doing nothing, it is possible that the benefits of these mega-constellations and a ◆ The number of collisions will increase tenfold or booming new space industry would outweigh the more, producing possibly one collision per year. costs on the global space enterprise, possibly even Imagine having a collision as disruptive as the 2009 spurring new innovation into the development of Iridium-Cosmos collision every year. robust, resilient satellites and architectures that can ◆ Mega-constellations would increase the number operate in the riskier space environment. of close-approach warnings by a factor of ten to ◆ Option 2: Refine and Impose Stricter Disposal one hundred. Using today’s thresholds, more than Requirements. Satellites today are required to sat- 25,000 warnings would be issued each day, all of isfy a set of disposal requirements that were drafted which must be adjudicated by the operators that re- well before the age of CubeSats, microsatellites, and ceive them. mega-constellations. In a world of mega-constella- ◆ After 200 years, the number of objects on orbit tions, Aerospace analysis has shown that the current greater than 10 centimeters in size could exceed 25-year rule for natural disposal would lead to more 500,000, a factor of five greater than without the than 100,000 baseball-sized objects in LEO by the mega-constellations. year 2100, and 500,000 by the year 2200—and that’s What Can Be Done? only from the constellations that would be launched in the 2020s. The current disposal requirements are Decision makers have only a few years before the con- clearly inadequate to prevent a tragedy of the com- sequences of unregulated mega-constellations are upon mons overtaking all the space around Earth. New us. In that time, there are three broad courses of action disposal requirements should be considered for that could be followed: promulgation both within the United States and 3 internationally, and enforced more assiduously than ◆ Option 1, Do Nothing: What is the cost versus ben- they are today. However, the analysis suggests that efit of letting the free market have its moment to even reducing the on-orbit lifetime of these mega- shine? Can some technical challenges to surviving constellations to only one year could still generate a hostile debris environment surely not be solved hundreds of thousands of baseball-sized objects in the 2020s? Will this laissez-faire approach likely over the next 200 years, largely due to the increased yield a net benefit or net loss for the space commu- frequency of collisions while the constellations are nity? Who wins? Who loses? active. ◆ Option 2, Disposal: What should new disposal re- ◆ Option 3: Orbit Licensing. Just as every operator quirements be? Are they qualitatively different from in space must acquire a license for radio-frequency how we view such requirements today? Who should spectrum, regardless of orbit, it may be necessary enforce the requirements, and how? What should to expand the licensing regime to the orbits them- the consequences be for failing to meet them? selves, whether in LEO, MEO, or GEO. Licensing ◆ Option 3, Orbit Licensing: Exactly how much li- for orbits, along with the aforementioned disposal censing is necessary or optimal? Can some orbit requirements, would regimes be left alone allow for an enter- and unregulated for prise-level assessment There is still time to elect a the foreseeable future? of the impact of a pro- Do only certain aspects posed satellite or con- policy response that both of the orbit need to be stellation, both on the encourages innovation and licensed? What are rea- debris environment sonable thresholds for as a whole and on the preserves the habitability of risk that would drive operations of satel- licensing decisions? lites already in orbit.
Load more

Recommended publications
  • In-Depth Review of Satellite Imagery / Earth Observation Technology in Official Statistics Prepared by Canada and Mexico
    In-depth review of satellite imagery / earth observation technology in official statistics Prepared by Canada and Mexico Julio A. Santaella Conference of European Statisticians 67th plenary session Paris, France June 28, 2019 Earth observation (EO) EO is the gathering of information about planet Earth’s physical, chemical and biological systems. It involves monitoring and assessing the status of, and changes in, the natural and man-made environment Measurements taken by a thermometer, wind gauge, ocean buoy, altimeter or seismograph Photographs and satellite imagery Radar and sonar images Analyses of water or soil samples EO examples EO Processed information such as maps or forecasts Source: Group on Earth Observations (GEO) In-depth review of satellite imagery / earth observation technology in official statistics 2 Introduction Satellite imagery uses have expanded over time Satellite imagery provide generalized data for large areas at relatively low cost: Aligned with NSOs needs to produce more information at lower costs NSOs are starting to consider EO technology as a data collection instrument for purposes beyond agricultural statistics In-depth review of satellite imagery / earth observation technology in official statistics 3 Scope and definition of the review To survey how various types of satellite data and the techniques used to process or analyze them support the GSBPM To improve coordination of statistical activities in the UNECE region, identify gaps or duplication of work, and address emerging issues In-depth review of satellite imagery / earth observation technology in official statistics 4 Overview of recent activities • EO technology has developed progressively, encouraging the identification of new applications of this infrastructure data.
    [Show full text]
  • Astrodynamics
    Politecnico di Torino SEEDS SpacE Exploration and Development Systems Astrodynamics II Edition 2006 - 07 - Ver. 2.0.1 Author: Guido Colasurdo Dipartimento di Energetica Teacher: Giulio Avanzini Dipartimento di Ingegneria Aeronautica e Spaziale e-mail: [email protected] Contents 1 Two–Body Orbital Mechanics 1 1.1 BirthofAstrodynamics: Kepler’sLaws. ......... 1 1.2 Newton’sLawsofMotion ............................ ... 2 1.3 Newton’s Law of Universal Gravitation . ......... 3 1.4 The n–BodyProblem ................................. 4 1.5 Equation of Motion in the Two-Body Problem . ....... 5 1.6 PotentialEnergy ................................. ... 6 1.7 ConstantsoftheMotion . .. .. .. .. .. .. .. .. .... 7 1.8 TrajectoryEquation .............................. .... 8 1.9 ConicSections ................................... 8 1.10 Relating Energy and Semi-major Axis . ........ 9 2 Two-Dimensional Analysis of Motion 11 2.1 ReferenceFrames................................. 11 2.2 Velocity and acceleration components . ......... 12 2.3 First-Order Scalar Equations of Motion . ......... 12 2.4 PerifocalReferenceFrame . ...... 13 2.5 FlightPathAngle ................................. 14 2.6 EllipticalOrbits................................ ..... 15 2.6.1 Geometry of an Elliptical Orbit . ..... 15 2.6.2 Period of an Elliptical Orbit . ..... 16 2.7 Time–of–Flight on the Elliptical Orbit . .......... 16 2.8 Extensiontohyperbolaandparabola. ........ 18 2.9 Circular and Escape Velocity, Hyperbolic Excess Speed . .............. 18 2.10 CosmicVelocities
    [Show full text]
  • Electric Propulsion System Scaling for Asteroid Capture-And-Return Missions
    Electric propulsion system scaling for asteroid capture-and-return missions Justin M. Little⇤ and Edgar Y. Choueiri† Electric Propulsion and Plasma Dynamics Laboratory, Princeton University, Princeton, NJ, 08544 The requirements for an electric propulsion system needed to maximize the return mass of asteroid capture-and-return (ACR) missions are investigated in detail. An analytical model is presented for the mission time and mass balance of an ACR mission based on the propellant requirements of each mission phase. Edelbaum’s approximation is used for the Earth-escape phase. The asteroid rendezvous and return phases of the mission are modeled as a low-thrust optimal control problem with a lunar assist. The numerical solution to this problem is used to derive scaling laws for the propellant requirements based on the maneuver time, asteroid orbit, and propulsion system parameters. Constraining the rendezvous and return phases by the synodic period of the target asteroid, a semi- empirical equation is obtained for the optimum specific impulse and power supply. It was found analytically that the optimum power supply is one such that the mass of the propulsion system and power supply are approximately equal to the total mass of propellant used during the entire mission. Finally, it is shown that ACR missions, in general, are optimized using propulsion systems capable of processing 100 kW – 1 MW of power with specific impulses in the range 5,000 – 10,000 s, and have the potential to return asteroids on the order of 103 104 tons. − Nomenclature
    [Show full text]
  • AFSPC-CO TERMINOLOGY Revised: 12 Jan 2019
    AFSPC-CO TERMINOLOGY Revised: 12 Jan 2019 Term Description AEHF Advanced Extremely High Frequency AFB / AFS Air Force Base / Air Force Station AOC Air Operations Center AOI Area of Interest The point in the orbit of a heavenly body, specifically the moon, or of a man-made satellite Apogee at which it is farthest from the earth. Even CAP rockets experience apogee. Either of two points in an eccentric orbit, one (higher apsis) farthest from the center of Apsis attraction, the other (lower apsis) nearest to the center of attraction Argument of Perigee the angle in a satellites' orbit plane that is measured from the Ascending Node to the (ω) perigee along the satellite direction of travel CGO Company Grade Officer CLV Calculated Load Value, Crew Launch Vehicle COP Common Operating Picture DCO Defensive Cyber Operations DHS Department of Homeland Security DoD Department of Defense DOP Dilution of Precision Defense Satellite Communications Systems - wideband communications spacecraft for DSCS the USAF DSP Defense Satellite Program or Defense Support Program - "Eyes in the Sky" EHF Extremely High Frequency (30-300 GHz; 1mm-1cm) ELF Extremely Low Frequency (3-30 Hz; 100,000km-10,000km) EMS Electromagnetic Spectrum Equitorial Plane the plane passing through the equator EWR Early Warning Radar and Electromagnetic Wave Resistivity GBR Ground-Based Radar and Global Broadband Roaming GBS Global Broadcast Service GEO Geosynchronous Earth Orbit or Geostationary Orbit ( ~22,300 miles above Earth) GEODSS Ground-Based Electro-Optical Deep Space Surveillance
    [Show full text]
  • Detecting, Tracking and Imaging Space Debris
    r bulletin 109 — february 2002 Detecting, Tracking and Imaging Space Debris D. Mehrholz, L. Leushacke FGAN Research Institute for High-Frequency Physics and Radar Techniques, Wachtberg, Germany W. Flury, R. Jehn, H. Klinkrad, M. Landgraf European Space Operations Centre (ESOC), Darmstadt, Germany Earth’s space-debris environment tracked, with estimates for the number of Today’s man-made space-debris environment objects larger than 1 cm ranging from 100 000 has been created by the space activities to 200 000. that have taken place since Sputnik’s launch in 1957. There have been more than 4000 The sources of this debris are normal launch rocket launches since then, as well as many operations (Fig. 2), certain operations in space, other related debris-generating occurrences fragmentations as a result of explosions and such as more than 150 in-orbit fragmentation collisions in space, firings of satellite solid- events. rocket motors, material ageing effects, and leaking thermal-control systems. Solid-rocket Among the more than 8700 objects larger than 10 cm in Earth orbits, motors use aluminium as a catalyst (about 15% only about 6% are operational satellites and the remainder is space by mass) and when burning they emit debris. Europe currently has no operational space surveillance aluminium-oxide particles typically 1 to 10 system, but a powerful radar facility for the detection and tracking of microns in size. In addition, centimetre-sized space debris and the imaging of space objects is available in the form objects are formed by metallic aluminium melts, of the 34 m dish radar at the Research Establishment for Applied called ‘slag’.
    [Show full text]
  • Spacecraft Network Operations Demonstration Using
    Nodes Spacecraft Network Operations Demonstration Using Multiple Spacecraft in an Autonomously Configured Space Network Allowing Crosslink Communications and Multipoint Scientific Measurements Nodes is a technology demonstration mission that was launched to the International Space Station on December 6, 2015. The two Nodes satellites subsequently deployed from the Station on May 16, 2016 to demonstrate new network capabilities critical to the operation of swarms of spacecraft. The Nodes satellites accomplished all of their planned mission objectives including three technology ‘firsts’ for small spacecraft: commanding a spacecraft not in direct contact with the ground by crosslinking commands through a space network; crosslinking science data from one Nodes satellite to the second Nodes spacecraft deployed into low Earth orbit satellite before sending it to the ground; and communication, one ultra high frequency autonomous reconfiguration of the space (UHF) radio for crosslink communication, and communications network using the capability an additional UHF beacon radio to transmit of Nodes to automatically select which state-of-health information. satellite is best suited to serve as the ground relay each day. The Nodes science instruments, identical to those on the EDSN satellites, collected The Nodes mission consists of two 1.5- data on the charged particle environment unit (1.5U) CubeSats, each weighing at an altitude of about 250 miles (400 approximately 4.5 pounds (2 kilograms) and kilometers) above Earth. These Energetic measuring about 4 inches x 4 inches x 6.5 Particle Integrating Space Environment inches (10 centimeters x 10 centimeters x Monitor (EPISEM) radiation sensors were 16 centimeters). This mission followed last provided by Montana State University in year’s attempted launch of the eight small Bozeman, Montana, under contract to satellites of the Edison Demonstration of NASA.
    [Show full text]
  • Build a Spacecraft Activity
    UAMN Virtual Family Day: Amazing Earth Build a Spacecraft SMAP satellite. Image: NASA. Discover how scientists study Earth from above! Scientists use satellites and spacecraft to study the Earth from outer space. They take pictures of Earth's surface and measure cloud cover, sea levels, glacier movements, and more. Materials Needed: Paper, pencil, craft materials (small recycled boxes, cardboard pieces, paperclips, toothpicks, popsicle sticks, straws, cotton balls, yarn, etc. You can use whatever supplies you have!), fastening materials (glue, tape, rubber bands, string, etc.) Instructions: Step 1: Decide what you want your spacecraft to study. Will it take pictures of clouds? Track forest fires? Measure rainfall? Be creative! Step 2: Design your spacecraft. Draw a picture of what your spacecraft will look like. It will need these parts: Container: To hold everything together. Power Source: To create electricity; solar panels, batteries, etc. Scientific Instruments: This is the why you launched your satellite in the first place! Instruments could include cameras, particle collectors, or magnometers. Communication Device: To relay information back to Earth. Image: NASA SpacePlace. Orientation Finder: A sun or star tracker to show where the spacecraft is pointed. Step 3: Build your spacecraft! Use any craft materials you have available. Let your imagination go wild. Step 4: Your spacecraft will need to survive launching into orbit. Test your spacecraft by gently shaking or spinning it. How well did it hold together? Adjust your design and try again! Model spacecraft examples. Courtesy NASA SpacePlace. Activity adapted from NASA SpacePlace: spaceplace.nasa.gov/build-a-spacecraft/en/ UAMN Virtual Early Explorers: Amazing Earth Studying Earth From Above NASA is best known for exploring outer space, but it also conducts many missions to investigate Earth from above.
    [Show full text]
  • Pointing Analysis and Design Drivers for Low Earth Orbit Satellite Quantum Key Distribution Jeremiah A
    Air Force Institute of Technology AFIT Scholar Theses and Dissertations Student Graduate Works 3-24-2016 Pointing Analysis and Design Drivers for Low Earth Orbit Satellite Quantum Key Distribution Jeremiah A. Specht Follow this and additional works at: https://scholar.afit.edu/etd Part of the Information Security Commons, and the Space Vehicles Commons Recommended Citation Specht, Jeremiah A., "Pointing Analysis and Design Drivers for Low Earth Orbit Satellite Quantum Key Distribution" (2016). Theses and Dissertations. 451. https://scholar.afit.edu/etd/451 This Thesis is brought to you for free and open access by the Student Graduate Works at AFIT Scholar. It has been accepted for inclusion in Theses and Dissertations by an authorized administrator of AFIT Scholar. For more information, please contact [email protected]. POINTING ANALYSIS AND DESIGN DRIVERS FOR LOW EARTH ORBIT SATELLITE QUANTUM KEY DISTRIBUTION THESIS Jeremiah A. Specht, 1st Lt, USAF AFIT-ENY-MS-16-M-241 DEPARTMENT OF THE AIR FORCE AIR UNIVERSITY AIR FORCE INSTITUTE OF TECHNOLOGY Wright-Patterson Air Force Base, Ohio DISTRIBUTION STATEMENT A. APPROVED FOR PUBLIC RELEASE; DISTRIBUTION UNLIMITED. The views expressed in this thesis are those of the author and do not reflect the official policy or position of the United States Air Force, Department of Defense, or the United States Government. This material is declared a work of the U.S. Government and is not subject to copyright protection in the United States. AFIT-ENY-MS-16-M-241 POINTING ANALYSIS AND DESIGN DRIVERS FOR LOW EARTH ORBIT SATELLITE QUANTUM KEY DISTRIBUTION THESIS Presented to the Faculty Department of Aeronautics and Astronautics Graduate School of Engineering and Management Air Force Institute of Technology Air University Air Education and Training Command In Partial Fulfillment of the Requirements for the Degree of Master of Science in Space Systems Jeremiah A.
    [Show full text]
  • Brief Introduction to Orbital Mechanics Page 1
    Brief Introduction to Orbital Mechanics Page 1 Brief Introduction to Orbital Mechanics We wish to work out the specifics of the orbital geometry of satellites. We begin by employing Newton's laws of motion to determine the orbital period of a satellite. The first equation of motion is F = ma (1) where m is mass, in kg, and a is acceleration, in m/s2. The Earth produces a gravitational field equal to Gm g(r) = − E r^ (2) r2 24 −11 2 2 where mE = 5:972 × 10 kg is the mass of the Earth and G = 6:674 × 10 N · m =kg is the gravitational constant. The gravitational force acting on the satellite is then equal to Gm mr^ Gm mr F = − E = − E : (3) in r2 r3 This force is inward (towards the Earth), and as such is defined as a centripetal force acting on the satellite. Since the product of mE and G is a constant, we can define µ = mEG = 3:986 × 1014 N · m2=kg which is known as Kepler's constant. Then, µmr F = − : (4) in r3 This force is illustrated in Figure 1(a). An equal and opposite force acts on the satellite called the centrifugal force, also shown. This force keeps the satellite moving in a circular path with linear speed, away from the axis of rotation. Hence we can define a centrifugal acceleration as the change in velocity produced by the satellite moving in a circular path with respect to time, which keeps the satellite moving in a circular path without falling into the centre.
    [Show full text]
  • Space Sector Brochure
    SPACE SPACE REVOLUTIONIZING THE WAY TO SPACE SPACECRAFT TECHNOLOGIES PROPULSION Moog provides components and subsystems for cold gas, chemical, and electric Moog is a proven leader in components, subsystems, and systems propulsion and designs, develops, and manufactures complete chemical propulsion for spacecraft of all sizes, from smallsats to GEO spacecraft. systems, including tanks, to accelerate the spacecraft for orbit-insertion, station Moog has been successfully providing spacecraft controls, in- keeping, or attitude control. Moog makes thrusters from <1N to 500N to support the space propulsion, and major subsystems for science, military, propulsion requirements for small to large spacecraft. and commercial operations for more than 60 years. AVIONICS Moog is a proven provider of high performance and reliable space-rated avionics hardware and software for command and data handling, power distribution, payload processing, memory, GPS receivers, motor controllers, and onboard computing. POWER SYSTEMS Moog leverages its proven spacecraft avionics and high-power control systems to supply hardware for telemetry, as well as solar array and battery power management and switching. Applications include bus line power to valves, motors, torque rods, and other end effectors. Moog has developed products for Power Management and Distribution (PMAD) Systems, such as high power DC converters, switching, and power stabilization. MECHANISMS Moog has produced spacecraft motion control products for more than 50 years, dating back to the historic Apollo and Pioneer programs. Today, we offer rotary, linear, and specialized mechanisms for spacecraft motion control needs. Moog is a world-class manufacturer of solar array drives, propulsion positioning gimbals, electric propulsion gimbals, antenna positioner mechanisms, docking and release mechanisms, and specialty payload positioners.
    [Show full text]
  • Cislunar Tether Transport System
    FINAL REPORT on NIAC Phase I Contract 07600-011 with NASA Institute for Advanced Concepts, Universities Space Research Association CISLUNAR TETHER TRANSPORT SYSTEM Report submitted by: TETHERS UNLIMITED, INC. 8114 Pebble Ct., Clinton WA 98236-9240 Phone: (206) 306-0400 Fax: -0537 email: [email protected] www.tethers.com Report dated: May 30, 1999 Period of Performance: November 1, 1998 to April 30, 1999 PROJECT SUMMARY PHASE I CONTRACT NUMBER NIAC-07600-011 TITLE OF PROJECT CISLUNAR TETHER TRANSPORT SYSTEM NAME AND ADDRESS OF PERFORMING ORGANIZATION (Firm Name, Mail Address, City/State/Zip Tethers Unlimited, Inc. 8114 Pebble Ct., Clinton WA 98236-9240 [email protected] PRINCIPAL INVESTIGATOR Robert P. Hoyt, Ph.D. ABSTRACT The Phase I effort developed a design for a space systems architecture for repeatedly transporting payloads between low Earth orbit and the surface of the moon without significant use of propellant. This architecture consists of one rotating tether in elliptical, equatorial Earth orbit and a second rotating tether in a circular low lunar orbit. The Earth-orbit tether picks up a payload from a circular low Earth orbit and tosses it into a minimal-energy lunar transfer orbit. When the payload arrives at the Moon, the lunar tether catches it and deposits it on the surface of the Moon. Simultaneously, the lunar tether picks up a lunar payload to be sent down to the Earth orbit tether. By transporting equal masses to and from the Moon, the orbital energy and momentum of the system can be conserved, eliminating the need for transfer propellant. Using currently available high-strength tether materials, this system could be built with a total mass of less than 28 times the mass of the payloads it can transport.
    [Show full text]
  • GEO, MEO, and LEO How Orbital Altitude Impacts Network Performance in Satellite Data Services
    GEO, MEO, AND LEO How orbital altitude impacts network performance in satellite data services COMMUNICATION OVER SATELLITE “An entire multi-orbit is now well accepted as a key enabler across the telecommunications industry. Satellite networks can supplement existing infrastructure by providing global reach satellite ecosystem is where terrestrial networks are unavailable or not feasible. opening up above us, But not all satellite networks are created equal. Providers offer different solutions driving new opportunities depending on the orbits available to them, and so understanding how the distance for high-performance from Earth affects performance is crucial for decision making when selecting a satellite service. The following pages give an overview of the three main orbit gigabit connectivity and classes, along with some of the principal trade-offs between them. broadband services.” Stewart Sanders Executive Vice President of Key terms Technology at SES GEO – Geostationary Earth Orbit. NGSO – Non-Geostationary Orbit. NGSO is divided into MEO and LEO. MEO – Medium Earth Orbit. LEO – Low Earth Orbit. HTS – High Throughput Satellites designed for communication. Latency – the delay in data transmission from one communication endpoint to another. Latency-critical applications include video conferencing, mobile data backhaul, and cloud-based business collaboration tools. SD-WAN – Software-Defined Wide Area Networking. Based on policies controlled by the user, SD-WAN optimises network performance by steering application traffic over the most suitable access technology and with the appropriate Quality of Service (QoS). Figure 1: Schematic of orbital altitudes and coverage areas GEOSTATIONARY EARTH ORBIT Altitude 36,000km GEO satellites match the rotation of the Earth as they travel, and so remain above the same point on the ground.
    [Show full text]