Value chain · CLM-1189
In plain terms
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.
The claim as recorded
A 1990 NASA Lewis zero-order feasibility study of beaming power from solar-powered satellites in lunar orbit to the Moon's surface assumed satellites in circular equatorial lunar orbits supplying one equatorial base through a fixed, flat, horizontal, non-tracking rectenna with an assumed 135 degree field of view. On that basis its orbit table gives the number of satellites needed for continuous coverage falling from 30 at 90 km altitude to 3 at 10,566 km, with 4 at 2,459 km (orbit period 6.78 h, eclipse 0.92 h, beam time 1.7 h), and below 1,336 km the eclipse time is longer than the beam time.
Evidence behind this: T3, a NASA Lewis Research Center conference paper (25th IECEC, Reno, August 1990) that calls itself a "zero-th order" feasibility analysis (PDF 3 [1]) and "an initial scoping document": spreadsheet projections, not built hardware.
Scope and limits
A SCOPING STUDY'S SIMPLIFICATION, NOT AN OPTIMUM. The equatorial orbits and the single equatorial base were chosen "To reduce the complexity of the problem" (PDF 3), and the paper proposes inclined elliptical orbits as future work, for shorter eclipses (PDF 8). The 135 degree field of view is an assumption. Table 2's text layer is OCR-damaged; the figures here were read at render.
What it assumes
No assumptions are recorded against this claim.
Where it comes from
PDF 3 [1]: "satellite(s) were assumed in circular equatorial orbits around the moon, supplying continuous power to a single equatorial base through a fixed horizontal rectenna on the surface"; same page: "a fixed non-tracking rectenna". PDF 6 [4]: "The receivers were taken to be placed flat horizontally on the surface with an assumed field of view of 135" (a degree sign follows on the page); "For altitudes less than 1336 km, the eclipse time is greater than the beam time". Table 2 "Orbit Parameters", "all times in hours", read at render: 90 km, 30 satellites; 2459 km, orbit period 6.78, eclipse .92, 4 satellites, beam time 1.7; 10566 km, 3 satellites.
Basis: orbit altitude in km; number of satellites for continuous coverage; orbit, eclipse and beam times in hours; receiver field of view in degrees
Cite this
energyaperture.com/c/clm-1189
CLM-1189, Energy Aperture, as of 1990-08.
Connected records
Other published records linked to this one. A list, not a judgement.
- Also from SRC-393
- CLM-1190The 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...CLM-1191The study sized its transmitting and receiving antennas with a standard beam formula, assumed about half the transmitted power would be...CLM-1192With 1990 technology the orbiting system came out heavier per kilowatt than solar panels on the ground with enough storage for the lunar...