have been seen in the efficiency of crystalline photovoltaic and thin-film solar cells. Lighter-weight substrates and blankets have been developed and flown. A 65-kW solar array has been installed successfully on the International Space Station, and wireless power transmission has been the subject of several terrestrial tests. Japanese and Canadian experiments, some of which are discussed later in this report, have shown that small aircraft can be kept aloft by power transmitted via microwaves. The area of robotics, essential to SSP on-orbit assembly, has shown substantial improvements in manipulators, machine vision systems, handeye coordination, task planning, and reasoning. Advanced composites are in wider use, and digital control systems are now state of the art.

Although scientific and engineering advances may help make SSP more feasible, the committee noted that public concerns about environmental degradation are, if anything, even more intense than in the days of the Fresh Look study.

1-3 STUDY APPROACH

The NRC formed a committee of eight experts with experience in space systems design, engineering, and launch; solar power generation, management, and distribution; on-orbit assembly; robotics; space structures; and economics to independently assess the technical investment strategy of NASA’s space solar power program. The full statement of task, found in Appendix A, asked the committee to address areas of the space solar power investment strategy associated with developmental and operational issues, technical feasibility of various aspects of the program, and opportunities for synergy. The committee restricted its efforts to critiquing NASA’s technical investment strategy and neither advocated nor discouraged the concept of space solar power. Assessments of (and comparisons with) other space solar power concepts, such as the Lunar Solar Satellite concept proposed by David Criswell, were not performed by the committee. The committee also did not attempt to predict the role that space solar power might play in the future among the many alternatives for generating electricity. The purpose of this assessment was to evaluate the technology investment strategy of the SERT program and provide guidance as to how the program can be most effective in meeting its long-term goals, not to influence those goals. This assessment evaluates the SERT program and the follow-on SSP R&T efforts through December 15, 2000. Program changes after that date are not included.

The committee approached the study by adopting the SERT program’s definition of the term “investment strategy,” which includes six areas: (1) program division and organization, (2) use of developmental cycles, (3) opportunities for independent review, (4) balance of internal and external investments, (5) use of systems analysis and modeling to define goals, and (6) periodic review of technology roadmaps. This definition then served as an outline for the approach that the committee used during its assessment.

This report focuses on two levels of assessment: (1) an overall evaluation of the technical investment strategy and program organization and (2) evaluation of individual technology subprograms. Chapter 2 examines the overall investment strategy, the investment strategy methodology, program management issues, and opportunities for synergy with other programs. Recommendations and discussion are categorized in three major areas. Chapter 3 provides individual evaluations of 11 of NASA’s 12 technical investment areas (economics is included in the overall assessment in Chapter 2). Recommendations called out in the Executive Summary and listed in Figure ES-1 were considered key by the committee. Other recommendations in Chapter 3 were considered important to managers of individual technology areas.

REFERENCES

EIA (Energy Information Administration). 2000. International Energy Outlook 2000. Washington, D.C.: U.S. Department of Energy, p. 114.


Feingold, Harvey, Michael Stancati, Alan Freidlander, Mark Jacobs, Doug Comstock, Carissa Christensen, Gregg Maryniak, Scott Rix, and John Mankins. 1997. Space Solar Power: A Fresh Look at the Feasibility of Generating Solar Power in Space for Use on Earth. Report No. SAIC-97/1005. Chicago, Ill.: Science Applications International Corporation (SAIC).


Glaser, Peter. 1968. “Power From the Sun: Its Future.” Science, Vol. 162, No. 3856, November 22, pp. 857–866.

Grey, Jerry. 2000. “The Technical Feasibility of Space Solar Power.” Statement to Subcommittee on Space and Aeronautics, Committee on Science, U.S. House of Representatives. September 7.


National Research Council (NRC), Environmental Resources Board. 1981. Electric Power from Orbit: A Critique of a Satellite Power System. Washington, D.C.: National Academy Press.


OTA (Office of Technology Assessment). 1981. Solar Power Satellites. NTIS No. PB82–108846. Washington, D.C.: U.S. Government Printing Office, p. 3.



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