These solar array areas are based on the efficiencies given in section IV-A-2 and a solar constant of 1353 W/m^, but have been increased 4.3 percent to allow for losses due to orientation perpendicular to the orbit plane (POP) so that the annual average DC output power is 5 GW per rectenna. This means that maximum output is 5.2 GW, which slightly exceeds the transmitter and ionosphere power density limits of section IV-A-1. It is assumed that the uncertainty associated with these limits is great enough that a problem will not exist. The unit weight basis, where available, is given in the tables. For a given unit weight, secondary structure (item 1.2) was assumed proportional to array area and array power distribution (1.9) proportional to the 3/2 power of area. Antenna power distribution (2.7) and microwave generators (2.9) were assumed to be proportional to the power level at those stages of the transmission process. Totals have been increased by 50 percent to account for probable growth. The variation of weight with efficiency and unit weights can be more easily visualized by reference to figure IV-A-5-2, although the apparently large range of weights is misleading for several reasons. First, it is unlikely that all efficiencies will be at the minimum, or at the maximum, simultaneously. Thus, the probable range of overall efficiency is narrower than shown. Second, a similar argument can be made for unit weights, although perhaps less convincingly. Finally, high efficiencies are, in general, not achieved concurrently with low unit weights, so that the lower left and upper right corners of the region are relatively unlikely to occur.
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