requires unique assembly methods to achieve the needed production rates. The integration of the power-bus system to the central mast and eventual mating to the antenna subassembly follows. This mission supported by the preceding missions is considered to offer one way of obtaining the flight test data pertinent to the implementation of objective M2. Although more or less complex implementation may be recommended as the program definition matures, these mission concepts are therefore used as the basis to scope the characteristics of an orbital test facility as described in the following paragraphs. The conceptual design results in a 15 MW power source requirement to fully implement the currently defined highly desirable objective for ionosphere HFH layer irradiation. The configuration builds up in Missions 2 through 10. The solar array is assumed to have a concentration ratio of two. The silicon solar blanket efficiency was established using the projected efficiency for the SEPS array (12 percent) and degrading efficiency for the operating temperature at a concentration ratio of two. A power distribution system efficiency of 92 percent was assumed and the projected microwave conversion efficiency of 82 percent was utilized to compute the array output power requirement. The array weight estimates used the projected SEPS solar blanket weights (0. 525 kg/m ) and the 0. 5 mil aluminized Kapton weights projected for the operational mirror system. The weight per unit length of structure for the operational satellite was used to establish the non-conducting structural weights. The column lengths for this design are approximately the same as the operational system. The weight of the conducting structure and central mast are sized by electrical requirements in the operational system; but are sized by structural requirements in this system. The rotary joint is scaled down (1/10 size) from the operational system. The total weight of the orbital test facility is 228, 343 kg (503, 148 lb). The transmitting antenna, however, is 3.6 times heavier than the solar array. This introduces unique control problems compared to the operational system. The antenna should be used as the base for the spacecraft reaction control system and the rotary joint used to steer the array. This combination may lead to problems meeting the objective, to point to a ground rectenna, and complicating ionospheric testing to an even greater extent.
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