Section 3 TECHNICAL DISCUSSION 3.1 MISSION ANALYSIS 3.1.1 SSPS Configuration and Flight Mode Descriptions The Satellite Solar Power Station (SSPS), as presently conceived, is a geosynchronous equatorial placed satellite whose function it is to collect solar energy and radiate it to the earth (see Fig. 3.1-1 and 3.1-2). Energy radiation to the earth would be accomplished by the Microwave Power Transmission System (MPTS), an integral part of the SSPS system. The overall size of the SSPS system (—5 km x 12 km) precludes launch into orbit by a single launch, but requires many launches to get the components of the system into low earth orbit. Once in low earth orbit (LEO) the system can be assembled and transported through the Van Allen belts to geosynchronous equatorial orbit. An alternate plan calls for SSPS assembly above the Van Allen belts (—7000 n mi) to avoid solar cell degradation which occurs while traversing the Van Allen radiation belts. The latter system would use a Tug to transport the SSPS components from LEO to 7000 n mi. Both assembly altitudes would use a Solar Electric Propulsion System (SEPS) to transport the assembled SSPS system from the assembly point to geosynchronous equatorial mission orbit. Similarly, both techniques would use Shuttles to transport materials from ground to LEO. In summary, the complete SSPS system consists of the following segments: • SSPS structure • MPTS antenna • SEPS • Stationkeep/control module (LEO assembly only). Figure 3.1-3 depicts the two flight modes, i.e., the low earth orbit assembly mode (Plan 1), and the high earth orbit (HEO, 7000 n mi) assembly mode (Plan 2). 3.1.2 Transportation System Performance 3.1.2.1 Shuttle Both of the flight modes described in the previous subsection utilize the Shuttle as the vehicle for transporting elements of the SSPS from ground to LEO. Due east Shuttle
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