Whether partial assembly in LEO or total assembly in GEO occurs, the system will have to be constructed in modular fashion so that as little difficulty as possible is encountered during assembly, and so that maximum transport efficiency can be achieved. This means the designer's attention must be focused on as high-density a package as possible for the collector and the radiator subsystems. Assembly operations would be conducted by meeting each load at some distance from the station with a manned tug which would bring the load to the station and dock with it. The load would then be transferred to a predetermined location on the assembly frame and secured. After buildup of the absorber cavity, with the turbo packages mounted on it, collapsible frames would be extended to serve as a base for radiator system mounting. From the nucleus containing over 50 percent of the weight of the system, collapsed support arms are extended from the cavity for construction of the reflector subsystem, the lightest, but largest, component of the system. The four modules would be attached one to another as they are completed, and the microwave system(s) would then be assembled on the module periphery. One power satellite per year would be constructed in this manner. An orbital assembly crew supported by a space station would accomplish the assembly task. Orbital assembly benefits include the absence of large gravity loads and the advantage of being able to use vacuum processes such as electron beam welding without vacuum facilities. However, problems exist, too, with orbital assembly, mainly those of earth eclipse and gravity gradient forces. 2.84 Operations and Maintenance Aspects Once the start sequence is initiated for the system, the turboalternators are never shut down. During periods of full sunlight (over 99% of the time), each turbogenerator produces a constant 300 Mwe. During eclipse periods (less than 1% of the time) turbopackage spinning reserve is relied upon, with thermal storage if required, to keep the shaft Jurning. This is to avoid start-up and shut-down of the gas bearing system, which can be done (even easier in low gravity), but which limits the life of the system. The radiator system would either have to be shuttered, which seems impractical for such a large-area system; or the fluid would be allowed to freeze; or, thermal storage for the heat rejection system could be provided. A small amount of parasitic power would be required to operate the individual facet servos, and in the event of a fluid loop failure, the reflector facets would automatically be defocused to protect the absorber. Make-up fluids would be supplied to the system from a tank farm attached to the station, and surface coating refurbishment or replacement would be performed by a support crew, which would also monitor system performance from a central power plant control facility and provide other maintenance functions as required. * Latest investigation indicates that the size of the turbomachinery is such that much lower operating speeds than originally envisioned would be necessary - in which case conventional bearings may be preferable.
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