Solar Power from Luna

• Dr. David Criswell has suggested that instead of using lunar materials to build solar power plants orbiting Earth, the solar power could be generated on Luna and beamed directly to Earth.^[1] Mike Combs questioned why one would build a solar power plant on Luna where the sun shines only half the time, when the raw materials from Luna could be made into a power station in GEO (geostationary Earth orbit) with sunshine 98% of the time.
• The mass driver needed to put raw materials into orbit from Luna using only pennies per pound of power would take quite some time to build from lunar materials using a bootstrap strategy to build the lunar infrastructure. The capital cost for the electric power plant to run a mass driver on Luna would make the electricity cost quite a few pennies per pound. There is the problem Mike mentioned of orbital debris from a scheme to send raw materials to L2. Also L2 moves with relation to the solid surface of Luna because of a five degree angle between the normal of the plane of Luna’s orbit and the axis of Luna’s rotation, because of the varying angular speed of Luna’s orbit compared to the more constant speed of Luna’s rotation and because the distance from luna to L2 changes as the distance from Luna to Earth changes because of orbital eccentricity. All of these things complicate the aiming of an otherwise simple mass driver that would send raw material to L2. A circumpolar mass driver with a catching satellite in an orbit with an inclination of 86.8 degrees would avoid these complications but would be a larger project.
• On Earth the productive capacity per person rose almost continuously in the western civilization for the last 2000 years. Small setbacks during economic depressions and wars were always more than made up for after the setback. This has caused the cost of production in terms of man-hours to decrease for 2000 years. We have reached limits of energy available for industry and environmental capacity to sustain industry. These limits are interfering with the growth of productive capacity per person on Earth, but will not limit lunar production for many years to come. It is this decrease in the cost of production with increased capacity that should make lunar supply of material for space-based solar power attractive. If mankind wants to continue increasing industrial capacity and decreasing unit costs, industrial production must be moved to where the energy and raw materials are available, outer space, Luna and Mars.
• reference

1. http://writings.mike-combs/LSP_vs_L-SPS.htm