SPS STRUCTURAL DYNAMICS AND CONTROL WORKSHOP: FINDINGS AND RECOMMENDATIONS R. C. Ried - NASA/JSC, Houston, Texas D. L. Mingori - University of California, Los Angeles, California Recently a technical workshop was held at the Johnson Space Center to examine issues related to the structural dynamics and control of the Solar Power Satellite (SPS), a concept which holds promise for meeting a portion of the energy needs of the United States beyond the year 2000. The panel members, listed in Figure 1, represent some of the nation's leading experts in controls, structural dynamics, structures and materials. As listed in Figure 2, the objectives of the workshop were for this panel to: 1) assess and critique the assumptions, methodologies and conclusions of existing SPS studies in the areas of structural dynamics and control (with structural design and materials also being considered) and 2) identify critical issues in these areas and make recommendations for future work. Within the time and resources available it was not possible to provide the panel with a comprehensive review of the overall SPS system characteristics or to penetrate into the intersystem design issues and tradeoffs. In fact the workshop was only able to highlight the activities in structures, control and materials. In spite of these limitations the panel has afforded an excellent review and developed a valid perception as to the status of the SPS work in their areas of expertise. This paper is based on preliminary inputs from the panel members. The official panel findings are expressed in the panel's final report. Comments and recommendations given include six categories as briefly addressed in: Figure 3. Modeling/Dynamic Analysis of the Uncontrolled System Figure 4. Structural Design Figure 5. Control System Analysis/Design Figure 6. Construction in Space Figure 7. Structural Materials Figure 8. Experiments A seventh category, manned safety, was pointed out by the panel as an important factor to all aspects of system design, construction, maintenance and operation. After considering each of these areas, the panel would like to have stated with some confidence that all of the problem areas had been brought to light and shown to be resolvable. In fact, they are generally optimistic that if sufficient resources are devoted to this effort, the same kind of technical know-how that has served us in the past will find ways to meet the challenges presented by the SPS. At the present time, however, such optimism would be based more on wishes and past success than on hard evidence. The work to date has simply not gone far enough or looked deep enough to provide real confidence in the ultimate viability of the SPS. A substantial amount of work must be done in areas like modeling, developing techniques for the active control of uncertain systems, and studying the long term physical properties of composites before this confidence will be warranted. Meanwhile, optimism must be balanced by a certain amount of caution combined with the determination to develop the tools and knowledge necessary to see if this much needed dream can be turned into reality. Since the SPS system cannot be tested in the terrestrial environment, many types of experimental verification techniques possible for more conventional engineering projects are ruled out. Thus, the successful design, development and con-
RkJQdWJsaXNoZXIy MTU5NjU0Mg==