With regard to the direct coupling of SPS microwave energy with other electromagnetic systems, models have been developed to predict the spatial and frequency distribution patterns of candidate antenna-rectenna concepts. Potential degradation of the performance of other satellites has been analyzed and appears to be no problem for adjacent satellites in geostationary orbit. Problems with the operation of sensors on satellites in lower orbits have been identified along with mitigation techniques that appear acceptable. Some effects on ground-based computers and communication systems have been identified that appear to be amendable to mitigation procedures, involving redesign of antenna and circuits, and the use of shielding. The greatest uncertainty appears to be in the area of radio-frequency emissions from the rectenna and associated structures. Experimental study of these questions is required. Potential impacts on radio and optical astronomy have been identified. It will be necessary to design SPS to operate within radio-frequency regulations designed to protect the radioastronomy service and to reduce the reflectance of the satellite structure to levels that will minimize the impact on optical astronomy. Societal Assessment As part of the Societal Assessment, material requirements have been assessed considering availability (differentiating between foreign and domestic sources), cost, energy requirements for production, and manufacturing capacity. The following materials will require special efforts to insure adequate supply: gallium, gallium arsenide, sapphire, and graphite (for graphite fiber composites). Regardless of how the system is defined, energy analyses have resulted in positive net energy ratios. Potentially eligible land areas for rectenna placement have been identified and are compatible with the projected geographical distribution of energy demand and utility operations. Water sites are also being studied. While there are no obvious impediments to SPS in space law or custom, claims of some equatorial nations to space over their boundaries will require attention. A public outreach effort has succeeded in involving several interested publics in the development and evaluation of the SPS program. Comparative Assessment To date, the comparative assessment efforts have concentrated on developing a methodology, on collecting traceable data for selected alternative technologies, and on auditing SPS cost information. The methodology report has been completed and published and data bases have been developed for alternative technologies that include [1] advanced clean coal systems, [2] combined coal, 13] nuclear breeders, [4] nuclear fusion, [5] nuclear light water reactors, and [6] central station photovoltaics. Comparisons will be based on cost and performance, health and safety, resource requirements, and environmental issues. CONCLUSION The Concept Development and Evaluation Program is on schedule, and the final Program Assessment Report will be completed in Fiscal Year 1980. This report along with the detailed publications will serve as the basis for United States decisions on the future of the SPS program.
RkJQdWJsaXNoZXIy MTU5NjU0Mg==