resources, and comparative assessments with other energy conversion methods, was already considered as part of the SPS Concept Development and Evaluation Program (CDEP), [3] and there is an existing framework for continuing these assessments. The studies supporting the CDEP examined an unprecedented variety of issues that might 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 a broad consensus rather than on narrowly defined expert opinion. SPS designs ranging from 10-5000 MWe have been studied, indicating the wide interest in the power generation potential. One reason for the increasing 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 chosen during the CDEP to provide a common basis for assessments. This ‘reference system', based on assumed guidelines, was established by NASA to evaluate environmental effects, explore societal concerns, and perform comparative assessments. It is a design concept based on known technologies of the early 1970s; it does not represent a system that was expected to be actually constructed. An operational SPS would use some of the many alternative technologies that already have been identified for advanced SPS designs and would thus be quite different from the SPS reference system [4]. The SPS represents a fertile field for innovations. Few of the potentially interesting alternative technologies have been analyzed in detail. It would be premature to choose from among them because the consequences of these technologies cannot be evaluated without a vigorous system study of the impact of advanced technologies on SPS designs at the system and subsystem levels, and information obtained from projects such as Powercraft. The implicit assumption in the CDEP programme was that the SPS is a monolithic project requiring a massive commitment of funds over the next several decades. An approach can be devised for the development of the SPS that identifies the underlying generic technologies and their application to specific space projects, as shown in Fig. 1. The ‘terracing' of space projects would reduce the challenges typically associated with large-scale projects, including the control of the project, the effects of technical uncertainties, maintenance of investor confidence, reduction of environmental impacts, and the difficulties associated with termination of the project if warranted. The increasing capabilities needed for planned space projects-free-flying carriers, manned space stations, and space transportation systems of higher performance and lower cost-will contribute to the industrial infrastructure that could be the foundation for SPS development. As shown in Fig. 1, the SPS is only one potential application of space technology that could evolve from future space projects. However, projects such as the SPS are unlikely to be pursued until information from space projects at successive ‘terrace' levels can guide the evolution of the most appropriate design for the SPS. The designs that employ the most effective generic technologies can be developed, assessed, and analyzed, and the results shared with the participants in the SPS R&D programme. The assumption underlying the ‘terracing' approach is that advanced technologies will be developed in support of existing or planned national and international space projects. For example, some of the technologies that will be required for the SPS are being developed for near-term space applications, including telecommunications, remote sensing, materials processing, and space transportation. Specific technologies are being identified for future applications, such as Powercraft.
RkJQdWJsaXNoZXIy MTU5NjU0Mg==