SPACE SOLAR POWER REVIEW Volume 4, Numbers 1 & 2, 1983 Special Issue: Energy from Space PERGAMON PRESS New York / Oxford / Toronto / Paris/ Frankfurt /Sydney,
SPACE SOLAR POWER REVIEW Published under the auspices of the SUNSAT Energy Council Editor-in-Chief Dr. John W. Freeman Space Solar Power Research Program Rice University, P.O. Box 1892 Houston, TX 77001, USA Associate Editors Dr. Eleanor A. Blakely Lawrence Berkeley Laboratory Colonel Gerald P. Carr Bovay Engineers, Inc. Dr. M. Claverie Centre National de la Recherche Scientifique Dr. David Criswell California Space Institute Mr. Leonard David PRC Energy Analysis Company Mr. Hubert P. Davis Eagle Engineering Professor Alex J. Dessler Rice University Mr. Gerald W. Driggers L-5 Society Mr. Arthur M. Dula Attorney; Houston, Texas Professor Arthur A. Few Rice University Mr. I.V. Franklin British Aerospace, Dynamics Group Dr. Owen K. Garriott National Aeronautics and Space Administration Professor Norman E. Gary University of California, Davis Dr. Peter E. Glaser Arthur D. Little Inc. Professor Chad Gordon Rice University Dean William E. Gordon Rice University Dr. Arthur Kantrowitz Dartmouth College Mr. Richard L. Kline Grumman Aerospace Corporation Dr. Harold Liemohn Boeing Aerospace Company Dr. James W. Moyer Southern California Edison Company Professor Gerard K. O’Neill Princeton University Dr. Eckehard F. Schmidt AEG—Telef unken Dr. Klaus Schroeder Rockwell International Professor George L. Siscoe University of California, Los Angeles Professor Harlan J. Smith University of Texas Mr. Gordon R. Woodcock Boeing Aerospace Company Dr. John Zinn Los Alamos Scientific Laboratories Editorial Assistant: Edith R. Mahone Editorial Office: John W. Freeman, Editor-in-Chief, Space Solar Power Research Program, Rice University, P.O. Box 1892, Houston, TX 77001, USA.
ENERGY FROM SPACE John W. Freeman Editor Space Solar Power Research Program Rice University A Special Issue of SPACE SOLAR POWER REVIEW Pergamon Press New York • Oxford • Toronto • Paris • Frankfurt • Sydney
ISBN 0-08-030942-9 ISSN 0191-9067 Copyright ® 1983 Pergamon Press Ltd. Published as Volume 4, Numbers 1 and 2, of Space Solar Power Review and supplied to subscribers as part of their subscriptions. Also available to nonsubscribers.
SPACE SOLAR POWER REVIEW Volume 4, Numbers 1 & 2 1983 Special Issue: Energy from Space CONTENTS David C. Webb I Introduction Peter Jankowitsch 3 Energy from Space: A Vision of the Future Peter E. Glaser 11 Evolution of the Solar Power Satellite Concept: The Utilization of Energy from Space John M. Logsdon 23 Solar Power Satellites: The Institutional Challenge Jerry Grey 31 International Cooperation Robert O. Piland 35 A System Study of the Solar Power Satellite Concept Maurice J. Claverie 49 Market Potential and Possible Limitations for Alain P. Dupas Satellite Solar Power Stations J. Ortner 61 Space Research in Small Countries Frank P. Davidson 65 Macro-Engineering: An International Perspective C.A.S. Fawcett 71 Financing a Solar Power Satellite Project Derek Fraser 79 Insurance of Major Space Projects Manabu Nakagawa 83 An Asian Perspective: “Fin de Siecle” MacroInsurance Center on an Equatorial Island indexed in Current Contents, International Aerospace Abstracts, Energy Data Base, Energy Research Abstracts, and Engineering Index. ISBN 0-08-030942-9 ISSN 0191-9067 (611)
D. Kassing 87 European Questions Related to Satellite Power Systems Maxwell W. Hunter II 99 Transportation: Options and High Payoff Choices William C. Brown 119 An Electric Propulsion Transportation System from Peter E. Glaser Low-Earth Orbit to Geostationary Orbit Utilizing Beamed Microwave Power C.G.J. Wagner-Bartak 131 The Shuttle Remote Manipulator System: Canadarm—A Robot Arm in Space Makoto Nagatomo 143 Space Station: An Early Experimental Solar Power Satellite Ing B. Stoy 155 Power-Economical Considerations for the Integration of Terrestrial and Extraterrestrial Solar Generators into Existing Power Generation Systems Gordon R. Woodcock 169 Space Solar Power in Perspective Rashmi Mayur 183 Unispace 82: A Report of the Conference
0191-9067/83 $3.00 + .00 Copyright ® 1983 SUNSAT Energy Council INTRODUCTION This issue of Space Solar Power Review publishes some of the papers offered at a two-day symposium on “Solar Energy from Space” that was an integral part of the Non-Governmental Organizations (NGOs) Conference at the Second United Nations Conference on the Exploration and Peaceful Uses of Outer Space, Vienna, Austria, August 9-21, 1982. The caliber of the speakers and their international background reflects the importance attached to the SPS concept around the world. As such, it was important for this subject to be one of the central issues to be discussed at the NGO meeting. On behalf of the organizing committee, I would like to take this opportunity to publicly express our deep appreciation to Dr. Peter Glaser, who, as chairman of the International Committee on Energy from Space, put together such an excellent program. Another person who played a major role in this effort was Mr. Fred Osborn, whose untimely death in August, 1982, has so saddened all of us who knew him. Through the SUNSAT Energy Council, Fred worked tirelessly for the solar power satellite concept. He will be greatly missed — not only on that account but also as a friend and a gentleman in the true meaning of the term. The symposium proved a great success. Due to the separation of facilities, not as many government delegates were able to attend as had been hoped. But they were all aware of the subject matter and were greatly impressed by the high level of speakers who addressed the issues. The greatest impact of the symposium, however, resulted from the “Resolution on Energy from Space” that was forwarded by the NGOs to the governmental conference on behalf of the international council and became an official part of the proceedings. The resolution was reviewed by committee and undoubtedly influenced the formulation of the paragraphs on energy from space appearing in the final report of the conference. It is heartening to know from this and the numerous expressions of interest and concern about the issue at Unispace ’82 that the question of energy from space is very much in the forefront of people's minds — particularly those from the nonindustrial nations who are so well aware of their need for large amounts of inexpensive energy to aid in their development. It may take some years longer, particularly with the present worldwide recession, but the time for solar power satellites is fast approaching. It is essential therefore that a dialogue on the issues is kept open through conferences such as our own. The committee on NGOs at Unispace ’82 is proud to have played a part in maintaining this discussion. Dr. David C. Webb Chairman NGOs at Unispace 82
digitized by teh Space Studies Institute
0191-9067/83 $3.00 + .00 Copyright 1 1983 SUN SAT Energy Council ENERGY FROM SPACE: A VISION OF THE FUTURE PETER JANKOWITSCH Austrian National Assembly Parliament A 1017 Vienna, Austria Abstract — The SPS is one of the most promising nonpolluting power generation options which could contribute to meeting global energy demands in the 21st century. With proper organization and foresight, the nations of the world may one day collaborate in establishing a satellite solar power system to resolve their energy needs. INTELSAT and INMARSAT have emerged to provide exciting examples of the feasibility of such international efforts. The implications of SPS deployment are international in scope. An SPS would use outer space and radio frequency spectrum resources that are within the international domain. SPS would be subject to the present legal regime governing activities in outer space which encompasses two international organizations and three treaties. The world energy crisis of the seventies provided a severe, yet perhaps overdue awakening to nations of this planet long accustomed to abundant and inexpensive energy access. The era of abundant fossil fuels has ended. For nations in which energy had not yet achieved great status, the energy crisis constituted a grave setback to all established plans of economic and social development. As a result, the decade of the eighties will prove a period of intensive energy research and experimentation as national priorities are reexamined and adjusted to suit today's energy realities. For nations across the globe, the search for energy resources has seriously begun. For the developing countries, however, this search is both vital and urgent. Huge energy supplies will have to become available if the developing countries are to approach the economic level of industrialized countries. The future energy resource requirements of developing countries will be more than four times the total world energy production of 1970. As industrial countries will remain major users of the world’s energy resources, the prospect of supplying the equivalent of 30 billion metric tons to meet the aspirations of developing countries and the resulting global environmental effects, demonstrate that solar energy would have to play an increasingly important role. Solar energy could provide for virtually unlimited amounts of nonpolluting energy to meet all conceivable future needs. Yet, today, we are using practically no solar energy. Instead, we are burning cheap oil and gas and cheap oil and gas are limited resources. In principle, we have infinite energy in a finite world; whereas, in reality, we are using finite energy in a world that was, until recently, perceived to be infinite. Obviously, we cannot easily switch from the way we use our energy resources now to a future where we will use renewable resources. The advantages of solar power, whether collected in space or on Earth, are several. First among these is its flexibility in application on Earth. Solar energy can be used for heating, for producing synthetic liquid or gaseous fuel, for providing elec-
tricity and for the purification and distillation of water. Other uses, such as water heating, irrigation, timber and crop drying and drop protection, are also being tested in various countries. Solar power does not pose the danger of nuclear power plants whose wastes must be buried for thousands of years. It is a clean course of energy. Technically, the strength and constancy of the sun's rays in outer space as compared to their condition upon reaching Earth is of considerable importance. Each square meter of Earth’s surface exposed to sunlight at noon receives a total potential power input 100,000 times larger than the power produced in all the world’s electrical generating plants together. A solar power satellite placed in the geostationary orbit receives sunlight approximately 30% stronger than that received upon the ground and can provide a predictable supply of energy despite weather disturbances or interruptions by the diurnal cycle on Earth. As a result, it has been estimated that a satellite solar power system in the geostationary orbit could collect at least four times the solar energy which would be received on Earth. The SPS is one of the most promising power generation options which could contribute to meeting global energy demands in the 21st century. Its successful implementation (together with terrestrial solar energy conversion methods) could lead to the elimination of energy-related concerns. The successful development of the SPS would counteract the trends toward a stagnant society with prescribed limits to growth, and an aversion to risk taking. Therefore, in a broader sense, the development of the SPS goes counter to the frame of mind where every new technological development is “viewed with alarm” rather than "pointed to with pride” as an accomplishment. Our civilization has successfully unlocked the last frontier — space — which promises to lead to the extension of peaceful human activities beyond the confines of the Earth’s surface. On the basis of the increasing confidence in the feasibility and promise of the SPS, this option deserves serious consideration as humanity faces the challenges posed by the inevitable transition to renewable sources of energy. It seems altogether appropriate that the sun, which was the source of life, should continue as a fountain of energy for as long as it continues to shine. A satellite solar power system offers a single and general solution for global supply. Once such a system is in place, receiving stations could be constructed on a country or regional basis, offering a variety of methods for the supply of energy. Several countries might join together in constructing such a station, each slowly developing its own network of energy supply lines sustained by that primary regional energy source. Other nations might construct their own such stations and supply interested countries on a commercial basis. The commitment required to implement such a system would be unprecedented and yet its potential for energy supply is equally beyond the limited means of any single national energy programme. In terms of a global debate concerning the merits of a satellite solar power system, the developing countries would initially receive the most striking benefits. For example, the cost of one watt of electricity is higher in the developing countries, particularly in rural areas, than in the developed nations. As a result, the sudden availability of electricity in a developing country at a cost of $1-2 a watt may make solar energy highly competitive with other energy sources. In contrast, the cost of one watt in a developed country might have to drop as low as 50 cents in order to compete with established lower energy costs. One further benefit which developing countries, in particular, would enjoy is the availability of energy for rural populations. The World Bank has estimated that “electricity reaches only 4, 15 and 23 percent of the rural populations of Africa, Asia
and Latin America, respectively.” With the capacity of a terrestrial solar power receiving station for distributing such energy, vast areas of the Third World might acquire access to electricity on a much wider scale. As electrical systems are generally more fully established in the developed countries, the effects of solar power inputs would be less marked. One study has indicated that to add one solar power satellite to the electrical system in a country such as the United States, its capacity would be changed by two percent, whereas to add one solar power satellite in India would increase India’s electrical capacity by 40%. Since no single nation possesses the combination of resources and commitment essential for the establishment of a satellite system, such a system could be considered only in the context of an international programme based on a large proportion of the cost and technological capability being provided by the developed countries. This in itself would pose a major problem as the developed countries would require convincing that such tremendous investment would actually have a corresponding return. The developing countries, in contrast, have the least to contribute and the most to gain. However, a clearer view of a possible arrangement is provided by the example of INTELSAT, the international satellite communications organization founded in 1964. Since its inception, INTELSAT has grown from a cooperative of eleven interested countries to a total in 1980 of 102 members. The successful functioning of the organisation is based upon each member holding “an investment share based upon its use of the system” (subject to a minimum share of 0.15%). The revenues of the system are derived from utilization charges and, after the deduction of operating costs, are distributed to members in proportion to their investment share as amortization of their investment and as compensation for the use of capital. The major advantage and safeguard of an international organisation such as INTELSAT is the dual role of members as both owners and users. Through INTELSAT, many developing nations which could not afford the initial technological cost of satellite communications have now become active users. Not only has their participation afforded them access to an advanced field of space technology, they are receiving the considerable benefits of satellite communications in their development process. Information access is presently of major concern to the developing countries. Through INTELSAT such information is being supplied. Though the developing countries have profited significantly from the INTELSAT arrangement, the developed countries have also realized substantial benefits. First and most basic, these countries now share in a communications network of dimensions far beyond those that a single country could have afforded. These countries, just as the developing countries, are also enjoying the decreasing costs of a system which can provide economies of scale and the most advanced technology. For example, the annual cost of INTELSAT telephone circuit in 1965 was $64,000. In 1980, that cost had declined to $10,080. Further, INTELSAT provided those countries already possessing some technical know-how with the opportunity for additional research and development on a major scale. INTELSAT has thus provided substantial benefits to both developed and developing countries. Although the technology and much of the initial cost was provided by developed countries, the functioning of the system ensured them an adequate return on their investment. The growth of INTELSAT membership provides the clearest possible evidence that its potential is being realized to the benefit of both developed and developing countries.
Just as the communications needs of the world are being answered through organisations such as INTELSAT, so too could the global community share in supplying its basic energy needs. On such a scale the concept of a solar power satellite system could become feasible and only by means of such a system could the world hope to satisfy its tremendous energy requirements. Leaving aside for a moment the overriding consideration of cost, the advantages of such a system for both developed and developing countries are considerable. In this context, the advantages perceived by the developed countries are of equal importance to those recognized by the developing nations for, without adequate incentive, the developed countries will have no rationale for their initial, and crucial, participation in such a project. A real commitment to broad foreign participation in SPS development should be expressed concretely in the structure and operating practices of the organization. The voting structure within INTELSAT, INMARSAT and the IEA provides many mechanisms for participation. Relations between potential foreign participants could be improved by creating an equitable arrangement for the sharing of SPS technology and manufacturing responsibilities. Voting arrangements, particularly within INMARSAT, provide examples of how the Third World could participate in decision making and the sharing of benefits. A possible first step toward involvement of other nations might be the establishment of a research and development effort under IEA auspices. No one can predict the events which will shape the world in the next few years. However, the continued demand of both developed and developing nations for increasing energy supplies appears a relative certainty. As a result, no potential energy source should be dismissed without serious consideration. Satellite solar power systems, today considered a dream, could one day become the world's major energy source. For the developing countries, in particular, the concept of a satellite solar power system offers a promise for the future, but it is a promise which can be realized only through rational assessment, sincere commitment and the cooperation of the more technically advanced and industrialized nations. With proper organisation and foresight, the nations of the world may one day collaborate in establishing a satellite solar power system to resolve their energy needs. INTELSAT and more recently INMARSAT have emerged to provide exciting examples of the feasibility of such international efforts. In looking toward long-term solutions for the future, a satellite solar power system could provide an unprecedented opportunity for international cooperation and the satisfaction therewith of the most pressing need ever to face the nations upon this everchanging planet. INTERNATIONAL IMPLICATIONS The implications of SPS deployment are international in scope. An SPS would use outer space and radio-frequency spectrum resources that are within the international domain. At the same time, energy delivered by the SPS could be shared globally by developed and developing nations alike. International participation in its deployment could contribute to the improvement of international relations with regard to equitable energy distribution and consumption. An important international issue which should be noted is that controls are expected to be exercised by international organizations through enforcement of treaties governing operations in space and new agreements (e.g., on microwave radiation, geostationary orbit, and radio-frequency assignment) that may be required because of the unique aspects of the SPS.
International Agreements The present legal regime governing activities in outer space, to which the SPS would be subject, encompasses two international organizations and three treaties: • The U.N. Committee on the Peaceful Uses of Outer Space (UNCOPUOS) • The International Telecommunications Union (ITU) • 1967 Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space, Including the Moon and Other Celestial Bodies (UN) • 1973 Telecommunications Convention and Final Protocol Treaty • 1972 Convention on International Liability for Damage Caused by Space Objects (UN) Within UNCOPUOS, there has been little direct attention given to the potential importance of collecting and transmitting solar energy from space to Earth. The committee has shown significant interest in outer space, however, as exhibited by the long-running international debate over the draft Treaty Governing the Activities of States on the Moon and Other Celestial Bodies (the Moon Treaty). Under the 1967 Principles Treaty, the space environment is considered to be open to all who are able to use it. The radio-frequency spectrum, the geostationary orbit, and solar energy are considered natural resources of the space environment. As such, they fall within the “province of all mankind” pursuant to the 1967 Principles Treaty. In the case of the SPS, the consideration of space and its environs as the “province of all mankind” raises the question as to who should benefit from the space resource. The finite geostationary orbit space and increasing competition for its use will influence slot availability for the SPS. Some nations argue that the long-term use of a geostationary orbit slot is the same as appropriating it and is, therefore, in violation of existing international agreements. States with space capabilities have clearly established a customary rule of law, whereby outer space exists beyond the sovereignty of any nation-state. This rule exists in the absence of a formal delimitation between airspace and outer space and in the face of the Bogota Declaration, issued by eight equatorial countries asserting sovereignty over the geostationary orbit above their territory. Attaining SPS orbital slots requires considering: [1] some consensus on the first come, first served principle; |2| demonstration of efficient economic use and benefit to all; and [3] recognition that permanent utilization (i.e., ownership) of the orbital slot is not legal. The International Telecommunications Union (ITU), an autonomous, specialized agency of the United Nations, is now governed by the Telecommunications Convention and Final Protocol. Under this and previous telecommunications conventions, the ITU allocates use of radio frequencies, including microwave frequencies. The ITU is also responsible for preventing broadcast interference. There is a trend at ITU to link the radio spectrum with geostationary orbit position. Since 1973, the position of the ITU has consistently been that the geostationary orbit is a limited resource along with the radio-frequency spectrum. However, since the SPS has a power transmission, rather than a communications transmission, function, the ITU may not have authority over it. The 1972 Liability Convention covers the subject of harm caused by orbiting space objects. The convention also prohibits adverse changes in the environment. Although there is a present lack of knowledge about the health and environmental effects of low-level microwave exposure, clearly, a launching State would be inter-
nationally liable for harm produced by microwave radiation emanating from a space object. Any organization operating the SPS must have general international acceptance of microwave exposure standards in order to be safe from potential negligence suits. International agreement on microwave exposure standards may be reached much faster if a framework of bilateral agreements has been established between countries. The primary conclusion, after considering the legal regime to which the SPS would be subject, is that there are no unusual prohibitions against SPS deployment which could not be dealt with through international agreements. In terms of liability for operation of the SPS and its component parts, the scope and quality of international tort laws offer encouragement to those who may wish to embark on SPS programs. A future international regime governing activities in outer space, including SPS, will be influenced by a series of other international activities, including • The Law of the Sea negotiations • The Moon Treaty debate • World Administrative Radio Conferences • Deliberations regarding the legal status of the geostationary orbit Negotiations to implement the new Law of the Sea will establish precedents for the management of “common heritage” resources among nations and private parties. The outcome of these negotiations could produce another model of an organizational structure to develop and operate the SPS on an international basis. The concept of an international agency, such as the Seabed Authority, controlling and equitably disposing of the benefits of resources exploitation on behalf of the world community appears as a powerful precedent-setting accomplishment. The Moon Treaty has been the subject of negotiations within the UNCOPUOS for about 10 years. The main points of contention are possible restrictions placed upon space resource nations (particularly the United States) in the exploitation of the resources of the solar system. If the Moon Treaty should be ratified in its present form, there would be no immediate impact on the SPS in its reference configuration. The geostationary orbit is not covered in the treaty, and only Earth resources are contemplated for SPS development. Since there is so much ambiguity associated with the language of the treaty, these activities would represent a powerful precedent, which legal experts would be unlikely to ignore. If the Moon Agreement is adhered to without reservation by the technologically advanced countries, they would be well advised to take appropriate steps and measures initiating the internationalization of SPS now, while research and development (R&D) of the system is in its early phase, rather than proceed unilaterally in the misconception and unrealistic expectation that the large-scale transmission of solar power by satellites would escape the common heritage constraints of the Moon Agreement either by tacit international approval or otherwise. At the 1979 World Administrative Radio Conference (WARC-79), Third World nations were in the majority for the first time. They had been expected to demand a larger share of the radio-frequency spectrum hitherto dominated by the industrialized nations. This expectation was based in part on ideological opposition to some of the U.S. proposals offered at WARC-79. The Third World nations also feared that they were not technologically competent enough to ensure their retention of a fair share of the radio-frequency spectrum. Questions concerning the use of the geostationary orbit also have been formally
considered in this forum at least since the WARC-71 revision of the radio regulations concerning coordination of geostationary satellite positions. The Law of the Sea negotiations and the Moon Treaty debate also indicate a strong Third World desire to share the benefits of applying advanced technology to the problems of resource utilization. The geostationary orbit debate is a manifestation of an underlying political dispute over the implementation and interpretation of the principles embodied in the 1967 Outer Space Treaty, as are the claims of the Bogota nations to segments of the geostationary orbit. It is recognized that as satellite technology advances, the present regulatory regime may not be sufficient to equitably distribute the benefits derived from use of this orbit. Many legal experts are of the opinion that in the near future (apparently well before the SPS is operational), a new agreement for the rational use of the geostationary orbit will be negotiated. The UNCOPUOS is expected to assume an expanded role in this matter. The most significant aspect of the SPS concept is the global implication of continuous power generation available to all nations. International participation in an SPS program would also provide assurance of the program’s peaceful nature, adherence to agreed-upon environmental standards, and availability of power from space on a global scale. Furthermore, international involvement should assure that the SPS will not be controlled by any one industrial organization, sector of industry, or even one nation. Fears of military involvement could be an incentive to establishing a multinational regime to operate or regulate SPSs, and to prohibit militarily effective SPS designs. As the effects of the SPS technologies will extend past national frontiers, decisions regarding their development should not be left exclusively to national jurisdiction, but be made part of transnational affairs. The benefits of the SPS should be available on a global basis and should increase the opportunities for developing nations to take an active part in the utilization of energy available in space. The SPS concept should advance the complementary national interests of both developed and developing nations. A political consensus will need to emerge, in spite of diverse and contending interests, through widespread realization that humanity is embarked on a dangerous passage together in a world of finite resources, ultimate weapons, and unmet requirements. The significant progress that has been made as a result of the many studies being performed on the SPS is resulting in the growing conviction that the SPS is one of the promising power-generation options which could contribute to meeting global energy demands in the 21st century. Its successful implementation, together with energy conservation measures and solar energy applications on Earth, could lead to the elimination of energy-related concerns. The internationalization of SPS is virtually imperative for environmental considerations, military implications, the necessity of reaching international consensus on microwave exposure standards, geostationary orbital allocations and radio spectrum interference problems. Last but not least, the opening of SPS programs to full international participation would create a framework for the sharing of costs and responsibilities in the R&D phase which, in turn, may serve as a kind of measuring device in determining the distribution of benefits if and when the system becomes operational. The SPS could provide not only the impetus for peaceful cooperation among nations because all can share the limitless resources of space, but could also help civilization to make the inevitable transition to renewable sources of energy. The SPS provides a focus for international endeavors to utilize space to improve the
human condition on planet Earth and points a way toward a new direction for the evolution of the human species. The United Nations system has provided a very useful setting for the negotiations leading to agreed upon regimes for particular global activities such as space exploration and, hopefully, ocean exploitation. If SPS comes into being, it is almost certain that the UN will be engaged in creating such a regime for its operation. The experiment itself will attempt to put together an international project in space which will demand the cooperation of all nations. Notwithstanding the obstacles, the benefits of an inexhaustible, clean supply of energy could include a virtual internationalization of outer space. If the countries of the world worked toward this common goal, perhaps the destructive incentives to build arms would be overshadowed by the life power of the sun.
0191-9067/83 $3.00 + .00 Copyright ® 1983 SUN SAT Energy Council EVOLUTION OF THE SOLAR POWER SATELLITE CONCEPT: THE UTILIZATION OF ENERGY FROM SPACE PETER E. GLASER Arthur D. Little, Inc. Acorn Park Cambridge, Massachusetts 02410, USA Abstract — The utilization of the inexhaustible resources available in space is discussed with emphasis on solar energy conversion in orbit for use on Earth. The rationale for the solar power satellite (SPS) as a potential global energy supply option is presented, and the evolution of this concept since 1968 is traced. Alternative concepts for obtaining energy from space are also reviewed. The factors favoring the development of the SPS are highlighted, including projected dramatic increases in global electrical generating capacity. Environmental impacts and societal effects with emphasis on international participation in an SPS program are considered and the SPS is compared with alternative energy conversion methods. The international implications of the SPS are underlined and the common interests of both developed and developing nations in the development of the SPS as a 21st century option are recognized. The steps towards implementation of the SPS option are outlined in the context of achieving the inevitable transition to renewable sources of energy. Viewed from a historical perspective, few scientific and technical events have the stature of a genuine revolution in human affairs. The great events that have transformed the way men have lived, thought, and acted, ranging from the discovery of fire to the taming of the atom, must now include the conquest of space — a dimension that has until recently been unattainable, forbidding, elusive, and tantalizing in its unrevealed and unknowable promises. But, man is still too close to his entry into the space age to comprehend the potential impact of this achievement and his new capability. His evolution into space already has had global effects on communications and Earth observations. Success or failure in grasping the still beckoning opportunities provided by space resources will have as much influence on the destiny of society as the industrial revolution had on the development of the world economy. Some view space utilization as a diversion from worthwhile societal purposes, as an endeavor primarily of scientific interest, or as a form of entertainment covered by the mass media. Others view it as deserving to be recognized as the single, most pervasive influence on all future human activities. The growth of space utilization could have the most profound effects on the resolution of contemporary concerns, ranging from the availability of assured energy resources to meeting Third World nations’ economic aspirations. In the past, government institutions and industrial organizations have concentrated their planning and decision-making on the near-term, considering 5 to 10 years to be long-term. But that “myopic view” is questionable, even for strictly terrestrial endeavors. Space utilization strategies will have to be based on longer-term projected, if not ultimate, consequences, i.e., scenarios of various program options extending through the next 50 years. Although such scenarios impart a futuristic
connotation that may adversely affect decisions regarding necessary near-term research and development programs if the most promising technology options are to be exercised in the 21st century, they are required to focus near-term space missions in such a way as to obtain information on which to base succeeding missions. Given such a focus, generic space technologies can be developed to meet the requirements of a variety of space missions that could lead to step-by-step advances in the broadbased uses of space. But there is a wide divergence of views regarding the long-term impacts of specific space missions: the influence of advances in science and technology on future space activities; their competitiveness with similar activities performed on Earth; and the scale, timing, and effectiveness of governments' and industries’ investments in space programs in response to idealistic visions, pragmatic considerations, and political realities. Therefore, as important as the evolution of space technologies is to the planning and execution of specific space missions, economic, environmental, and societal issues also must be considered; and to ensure public support, they must be studied early and in parallel. In recent times, profound changes have occurred in the human condition; the undesirable ecological impacts of industrialization have been recognized and population growth has increased pressures to tap available natural resources. As a consequence, there are few known but unclaimed terrestrial resources waiting to be tapped. The upsurge in the material aspirations of people everywhere has coincided with wide acceptance of the proposition that limited resources and environmental constraints inexorably prohibit continued economic growth. However, models of social organization accept growth as a prerequisite for progress; no realistic economic system has been proposed which will permit adaptation to a stagnant society. As a result, confidence in the future has been eroded by a pervasive sense of the fragility of civilization. While space utilization cannot meet all the challenges facing society, the human prospect becomes much more encouraging when its potential benefits are taken into consideration. In sight is the technology to provide access to the limitless energy and material resources of the solar system which could sustain economic growth and advances in living standards of all people for as far into the future as can be reasonable projected. The availability of abundant energy without undesirable environmental consequences and at an acceptable cost is vital to any realistic approach to future economic growth. There is a growing consensus that humanity will increasingly rely on renewable energy resources which have their origin in the energy radiated by the Sun. Although there are many ways of reducing the magnitude of the energy supply challenges, only a few energy conversion methods have the potential to generate power continuously (baseload). In addition to known methods based on coal and nuclear fuels and the experimental ocean thermal energy conversion methods, there are two not-yet-demonstrated methods for baseload power generation in the 21st century: fusion and the solar power satellite, SPS. RATIONALE FOR THE SPS CONCEPT As originally conceived (1), an SPS could utilize various approaches, e.g., photovoltaic and thermal-electric, to solar energy conversion. From these, photovoltaic conversion was selected as a useful starting point because solar cells were already in wide use in communication, Earth observation and meteorological satellites, both in
low Earth orbit (LEO) and in geosynchronous orbit (GEO). Since then, an added incentive has been the substantial progress being made in the development of advanced photovoltaic materials and the increasing confidence in the ultimate achievement of significant cost reductions. In the SPS concept, solar cell arrays would convert solar energy directly into electricity and feed it to microwave generators forming part of a planar, phased-array transmitting antenna. The antenna would precisely direct a microwave beam of very low power density to one or more receiving antennas (i.e., rectennas) at desired locations on Earth. At the receiving antennas, the microwave energy would be safely and efficiently reconverted into electricity and then transmitted to users. An SPS system could consist of many satellites in GEO, each beaming power to one or more receiving antennas. The SPS concept challenged the view prevalent in the 1960s that solar energy conversion could not make a significant contribution to the global energy economies, and demonstrated that there are no « priori limits to the development of energy resources in space. Although not a panacea for the increasingly complex economic, environmental and societal problems, the SPS concept represents an alternative direction for developing renewable energy resources and for engaging in sustainable human activities in space in the 21st century. The energy which would be available on Earth from space could overcome the physical, societal, and institutional limitations to which future generations would be subjected by dwindling resources on Earth. Energy from space could break open the closed ecological system of planet Earth so that humanity need not be destined to live from generation to generation facing the threats of resource shortages and the resulting social upheavals. Extraterrestrial resources could satisfy some of the requirements of the global population in the 21st century; if these resources are not used, people’s insistence for improvements in living standards may be very difficult to meet. There is increasing confidence that, even with present space technology, the resources of the Moon — for example, oxygen, silicon, and aluminum — and possibly those in the asteroids could be the raw materials not only for the construction of the SPS, but also for other orbital industrial complexes so that they would no longer need to depend exclusively on terrestrial resources. The SPS concept has the unique advantage of not having to rely on a thermodynamic cycle to generate electricity on Earth, as is the case for fossil fuels and nuclear fission and fusion. It also can be the impetus for the development of space transportation systems and construction technologies to support a broad variety of industrial uses of space with useful intermediate and long-term applications. Furthermore, the SPS presents an opportunity for peaceful cooperation among nations in space. And finally, it has the potential to reduce conflict by eliminating the need for exploitation of energy resources at the expense of others; energy from space can be supplied on a global scale and thus be of benefit to all people. The SPS concept was conceived with the following objectives in mind: • To convert solar energy in space for baseload power generation on Earth; • To be of global benefit; • To conserve scarce resources; • To be economically competitive with alternative power generation methods; • To be environmentally benign; and • To be acceptable to the nations of the world.
The SPS concept is firmly founded on the premise that international participation in all phases of implementation will assure that the power generation and transmission technologies will only be used for peaceful purposes, and that the SPS will contribute to meeting future global energy demands. EVOLUTION OF THE SPS CONCEPT Since the SPS concept was first proposed, no other future energy macroengineering project has been studied as comprehensively from technical, economic, environmental and societal perspectives. Preliminary studies of the SPS concept were performed from 1968 to 1972. During that period, the SPS concept was discussed at many scientific and professional society meetings. In 1972, the Solar Energy Panel of the U.S. National Science Foundation outlined a plan for the SPS R&D program. Also in that year, NASA started a program to evaluate the feasibility of the SPS concept. In that feasibility study, a reference system design was adopted to provide a power output of 5 GW on Earth. In addition to structural design and control, RFI-avoidance techniques were investigated, and technological, environmental and economic issues were identified. In 1975, extensive system definition studies were started. In 1976, the principal responsibility for the SPS program was transferred to the Energy Research and Development Administration (ERDA). On the basis of its own appraisal, ERDA recommended that a more complete evaluation be made. At about that time, ERDA was reorganized and absorbed within the new U.S. Department of Energy (DOE). In 1977, DOE, working closely with NASA, started a three-year Concept Development and Evaluation Program (CDEP) (2), with a total budget of $19 million, to develop an initial understanding of the technical feasibility, economical practicality, and societal and environmental acceptability of the SPS concept. The CDEP provides a useful model for preliminary assessment of other energy conversion technologies. Although the depth of analysis was limited by the available funding, the studies supporting the program examined an unprecedented variety of issues which may influence development of the SPS. An explicit objective was to involve public interest groups in discussions about the SPS so that future decisions concerning the project could be based on broad consensus rather than on narrowly defined expert opinion. Many of the participants in the CDEP were initially skeptical about the SPS. However, no serious impediments to feasibility (other than uncertainties about cost) were identified and areas for continuing research were suggested (3). Since the conclusion of the CDEP, work related specifically to the SPS by U.S. Government agencies has not resumed, pending policy decisions about the future directions of the space program. There are, however, continuing studies, mostly funded by NASA, of technologies important to the SPS, including especially the areas of space transportation, large-scale construction in orbit, ion propulsion, space solar power conversion systems, and a permanent manned space station. When it became clear that the CDEP would produce results generally favorable to the SPS, a separate study was undertaken by a committee of the National Research Council (NRC), an agency of the National Academy of Sciences (4). Although several of the working groups involved urged continued research on the SPS, the resulting report is negative, primarily because overly conservative assumptions regarding the advances in solar energy conversion technology and space transportation sys-
terns resulted in prohibitive cost projections. An independent study, prepared by the Congressional Office of Technology Assessment, arrived at conclusions considerably more optimistic than those of the NRC (5). European technical studies of the SPS have also been performed. The British Department of Industry funded a study of the SPS, completed in 1979, which has led to growing interest by the British aerospace industry. The European Space Agency began assessments of the SPS in 1977, resulting in a number of papers in the ESA Journal in 1978. Interest in the SPS was expressed by ESA in 1978, and the agency has supported studies under the auspices of the International Astronautical Federation. In June 1980, an international symposium on the SPS was held in Toulouse, France, attracting representatives from many European nations and agencies (6). To date, most European studies have concentrated on developing European requirements for the SPS. Apart from innovative but generalized systems analyses (focussed particularly on techniques for reducing the area required for a receiving antenna), there has as yet been little attention to detailed engineering aspects of the system. In general, European analysts have relied on the results of the CDEP for technical information. Work also is or has been underway in Japan, Canada, Czechoslovakia, and India. There is also evidence that the U.S.S.R. has an interest in the SPS, based on its contribution to the international dialogue on the project. At the U.N. Conference on New and Renewable Sources of Energy, Nairobi, 1981, Soviet speakers implied that the U.S.S.R. intended to develop the SPS and use it to supply energy to Third World nations. ALTERNATIVE CONCEPTS FOR ENERGY FROM SPACE The SPS concept has motivated the consideration of alternative concepts for obtaining energy from space. A number of concepts have been proposed which use satellites to generate or transmit energy for use on Earth. While these concepts exhibit considerable differences in specific technologies required for their operation, in unit power output, and in projected costs, they all utilize space as an ideal medium for transmission of electromagnetic energy in the form of microwaves, laser light, or sunlight. The technology options which have been explored could use optical reflectors in space to provide continuous insolation at specified points on Earth; reflectors of microwave or laser beams to transmit power from point to point on Earth as an alternative to long transmission lines; and transmit power from satellites in orbit where either solar energy or nuclear energy is converted and beamed to a receiver at a desired location on Earth. In the foreseeable future, space systems requiring power supplies with continuous megawatt outputs will be developed. For some space power applications, nuclear reactors will be preferred, but solar energy conversions will also be used extensively. Beamed energy may be useful for supplying power to remote space systems, such as free-flyer carriers, or for laser propulsion. Therefore, it is reasonable to expect that technologies will be developed for generating significant quantities of electrical power in space and for transmitting power over long distances. There is considerable commonality between the projected space power applications over the nearer term and the conversion of energy in space for use on Earth. Development costs will most likely be spread over several potential applications and technologies which will reduce investment requirements for future space power applications will be preferred.
The concepts for utilizing energy from space for commercial purposes are directly applicable only to peaceful purposes. Beamed-energy devices conceived to disable satellites or missiles require a much higher flux on target than is required for power transmission. Furthermore, their power supplies are designed for peak power generation and transient operations rather than the continuous supply of baseload power which is inherent in the SPS concept. The SPS concept represents a generic technology which can be designed to meet a wide range of commercial power generation requirements. One of the reasons for confidence in the technical feasibility of the SPS is that alternative technologies have been identified for nearly all components of the system. Most studies have been concerned with the SPS reference system which was evolved to provide a common basis for a broad variety of studies which were subsequently carried out in the U.S. Department of Energy concept development and evaluation program. The SPS reference system is a conservative design which uses only known technologies which require limited development; it does not represent an optimized system. An operational SPS which could be developed during the next 20 years would use some of the 80 alternative technologies which already have been identified for advanced SPS designs and would be quite different from the SPS reference system. Just as one aircraft design does not meet all of the requirements of the air transportation industry, one SPS design will not suffice: a variety of SPS designs for different purposes will be developed. The SPS represents a fertile field for innovations. Few of the potentially interesting technological concepts have been analyzed in detail and it would be premature to attempt a choice among them, since the consequences of the new technologies cannot be evaluated without a vigorous system design study of the impact of technical changes at the system and subsystem levels. The SPS design objectives based on the use of several alternative technologies include the following: • The lowest feasible cost per unit power output; • Reduction of environmental and other external costs; • Cost-optimum power outputs over a range from 100 MW to 10 GW; and • Demonstration of performance of preferred system designs at costs low enough to reduce investments needed before returns will be available. The development of the most effective SPS designs for intended uses represents significant challenges, and these challenges must be met realistically. But it is as inappropriate now to discount the SPS as a major option for the 21 st century as it was for Simon Newcomb, American astronomer, to state in 1906 that “the demonstration that no possible combination of known substances, known forms of machinery and known forms of force can be united in a practical machine by which man shall fly long distances through the air seems to the writer as complete as it is possible for the demonstration of any physical fact to be." The forces of man's creativity will be a major ingredient in the successful development of the SPS concept. ECONOMIC FACTORS FAVORING DEVELOPMENT OF THE SPS The variability of solar insolation presents serious impediments to the exploitation of solar energy for generating baseload power with terrestrially based solar energy conversion systems. Because of interruptions by inclement weather and the diurnal
RkJQdWJsaXNoZXIy MTU5NjU0Mg==