On May 9, 1971, the Sunday papers published a syndicated cartoon, "Our New Age," which illustrated how energy could be beamed from Space to Earth to generate electricity. While the technology depicted in the cartoon had all the earmarks of science fiction, it was, in fact, based on a concept for a solar power satellite (SPS) which was proposed in 1968.
In 1980, such a power source now looks increasingly to be a technology whose time has virtually come. Its promise is enormous.
A single SPS could generate the equivalent power output of one to ten nuclear power plants. Placed in an orbit 22,300 miles above the equator, where the sun shines 24 hours a day during most of the year, and where the satellite would be stationary with respect to Earth (a geosynchronous orbit), the SPS would convert solar energy directly to electricity and feed it to microwave (radio) generators forming part of a transmitting antenna. The antenna would precisely aim a low-power density microwave beam to one or more receiving antennas at desired locations on Earth, and there microwave energy would be safely and efficiently reconverted to electricity and transmitted to users. The SPS is uniquely suited to generate power continuously because there are no interruptions by inclement weather and the diurnal cycle in this orbit.
Although it would be an advanced technology, such a power satellite system could be operational by the year 2000. It would be based on known technologies, which could be developed to accomplish the required functions in space. Of potential global benefit, the SPS concept has its roots in the scientific and technical resources, and aspirations, of a broadly based community which views space as a reservoir of unlimited energy and material resources. Since 1971 the SPS has been studied by academic institutions, industrial organizations, and government agencies in the United States, Canada, Britain, France, and Japan, by the European Space Agency, and by the Soviet Union. As a result, there is increasing recognition of its potential to meet future energy demands.
The most extensive assessment of the SPS concept was carried out during the past three years by the United States Department of Energy and the National Aeronautics and Space Administration. With a budget of $20 million, these two agencies had as their objective "to develop by the end of 1980 an initial understanding of the technical feasibility, economical practicality, and the societal and environmental acceptability of the SPS concept." The results of their assessment were reviewed at a conference held last April at the university of Nebraska, where 196 technical papers were presented on a wide variety of technical, economic, environmental, and societal issues.
The consensus emerging from the conference was that no reason has come to light for concluding that the SPS would not be technically feasible. Cost projections fall into a competitive range when the SPS is compared with power-generations systems using renewable or nonrenewable energy resources. Environmental issues dealing with long-term exposure to low-level microwaves, land use associated with receiving antennas, and the effects of rocket exhaust products on the atmosphere are not likely to constrain SPS development. The SPS has the potential to be environmentally benign compared with other large-scale continuous power-generation methods based on considerations of climatic effects, waste heat, pollutant release, and energy requirements during construction. however, the involvement of the public will be essential to alleviate concerns with environmental effects and control over a centralized large-scale technology.
In view of the growing interest in the SPS in the scientific community and in Congress, the National Academy of Sciences and the Congressional Office of Technology Assessment are also assessing the concept. Results of these assessments are expected in 1981 and will influence the evaluations and experiments to be carried out as part of the SPS program during the next several years, as well as legislation that may be introduced in Congress. Congress has supported the SPS program efforts of the Department of Energy and the National Eeronautics and Space Administration in the past and there are indications that this support will continue in the furure.
The SPS program is unique in that this major technology program focuses not just on key technology issues, but is concerned with the assessment of environmental effects and economic and societal issues so that risks and uncertainties can be identified before proceeding with the phase of a ground-experiment program. This focus for the SPS program is appropriate at a time when public skepticism of complex, large-scale technologies has been justified by well-publicized failures, and there is distrust of assurances that eechnologcal systems will not contribute to involuntary exposure to environmental, health, and safety hazards.
The most significant aspect of the SPS concept is the global implications of continuous power generation available to all nations. Once the overall feasibility of the SPS concept has been established, and the evaluations and ground experiments are concluded with positive results, other nations may be interested in joining the development and demonstration phases of the SPS program, and in experiments to be conducted on future space missions. Already there is significant international awareness of the SPS concept, as indicated by studies of the United Nations Committee for the Peaceful Uses of Outer Space, and discussions of frequency assignment and geosynchronous orbit positions at the World Administration Radio Conference which met in Geneva in August 1979. The SPS will also be discussed at an international symposium, sponsored by French government agencies, to be held in Toulouse, June 1980.
International participation in an SPS program would also provide asssurance 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.
TO derive the maximum benefits from a global SPS system, policies will have to be adopted which will be acceptable to other nations and lead to the formation of the most appropriate international organization devoted to SPS development and implementation. The organizational structure should be responsive to societal issues while the SPS is being developed so these issues won't have to be to be spliced in later. The organizational structure should also meet the common interests of participating nations, as already is the case with Intelsat, the organization controlling communications satellites and owned by more than 100 nations.
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 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.