SRC-393

Lunar Orbiting Microwave Beam Power System

Commissioned by NASA. Who paid for a study is recorded because it bears on how its conclusions should be read, not because it makes them wrong.

Published claims resting on this source

• CLM-1189 A 1990 NASA study of powering a Moon base from orbit put the satellites in circles over the Moon's equator, beaming down to a flat receiver at an equatorial base that can see a wide cone of sky. The higher the orbit, the fewer satellites it takes to keep one always in view: 30 at 90 km, 4 at about 2,500 km, 3 at about 10,600 km.
• CLM-1190 The study's reference design uses four satellites about 2,500 km above the Moon, each about the size of a space station (148 by 58 m): a 58 m square microwave antenna between two solar wings. Between them they beam a steady 1 MW to the base at 100 GHz, with batteries on board for when a satellite is in the Moon's shadow.
• CLM-1191 The study sized its transmitting and receiving antennas with a standard beam formula, assumed about half the transmitted power would be caught on the way down, and found that above 35 GHz the antennas are small enough that they stop mattering much to the total mass, and that going beyond 100 GHz gains little.
• CLM-1192 With 1990 technology the orbiting system came out heavier per kilowatt than solar panels on the ground with enough storage for the lunar night. With the technology the study projected, the four-satellite reference came to about 330 kg per kilowatt, below the roughly 500 projected for surface solar but far above the roughly 20 for a large nuclear plant.

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