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#### APPENDIX B

LUNAR SSPS POWER
Geosynchronous orbit is 35,400 km above the Earth, while Ll (the
location of SSPSs used for lunar power) is 64,400 km above the near
side of the Moon. Thus, if lunar SSPSs are identical to terrestrial
SSPSs, the microwave beam covers about twice as much area on the
surface of the Moon as compared to Earth. Changing the wavelength
can reduce beam spread but results in a loss in the (dc-to-dc)
efficiency of the system. Terrestrial SSPSs are assumed to transmit
at a 10 cm wavelength with 67 percent efficiency. Using information
provided by Glaser et.al. (ref. 4),
the relationship between microwave efficiency and beamwidth leads
to a lunar system with a wavelength of 3 cm, a 30 percent
efficiency, and using a rectenna area of 27 km^2

For the lunar system the rectenna is made up of 3,000
dipoles/m^2 and weighs 5 kg/m^2. All is produced on the Moon except
gallium arsenide for the diodes and possibly some dielectric
materials and glues which need to be brought up from Earth,
amounting to about 0.6 kg/m^2.

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