Solar panel belt around Moon
This idea sounds plausible, although easier said than done:
Japanese firm plans 250 mile-wide solar panel belt around Moon
The article is not at all detailed, so there is no indication of what sort of design studies have been done. I can think of a few problems:
- There is an electrostatic "wind" on the Moon caused by the Sun. At dawn, fine particles of the regolith "levitate" off the surface. The same electrostatic action resulted in some dirty astronauts during the Apollo missions. I imagine engineers could work out some sort of electrical repulsion to keep Solar panels clean, but it will be a concern.
- A 400 kilometer-wide belt around the equator of the Moon is a lot of surface area. I understand that current Solar cells have a "half-life" of years, degrading in effectiveness with age. So aside from the initial installation of this massive collector, panels will need routine replacement. And if this ultra-wide belt has no breaks between panels, the above mentioned dust might need a conveyor system.
- Focusing the power from the collector back to an Earth receiver has multiple problems. Laser pulses fired at the Moon form a spot 6.5 kilometers wide, yet scientists liken this to shooting a moving dime with a rifle from 3 kilometers away. Pinging a laser reflector on the Moon is nothing compared to beaming terawatts of power down from the Moon in an unending stream. If that beam should drift even a tiny bit from the Moon's libration, quakes on either body, atmospheric effects, etc... (See Asimov's story "Reason" in I, ROBOT.) Japan, of all places, has very little unpopulated land to afford a margin of safety around a receiving station.
- And there's more to a receiving station than a safety margin for beam collimation and drift. The rotation of the Earth would put any single receiving station out of range for most of the day. So for this massive Solar collector idea to work, Earth would need a web of receivers—all of which would have to be no-fly zones on our busy little planet. If you thought wind turbines and Solar furnaces were bad for birds...
"No, I better not look. I just might be in there."
—Foghorn Leghorn, Little Boy Boo