Re: LUNA: Re: indigenous fuels

Michael S. Lorrey (
Thu, 22 Jul 1999 21:22:24 -0400

Eugene Leitl wrote:
> writes:
> Well, there seem to be at least 20 Mt water buried at the
> pole(s). Let's await the Lunar Prospector crash, perhaps if we're
> lucky we'll see some water spectroscopically.
> Using it for fuel would be somewhat wasteful, though. Otoh, there is
> no telling how much water ice a comet core has, the difficulties to
> capture it and spin it down to lunar surface are not so very small
> however.

A ban on removing water from the Moon would be the only environmental law I could think of for space.

> > As of a couple of years ago the leading contendor was a mixture of aluminum
> > powder and liquid oxygen; it's not very efficient, but good enough to get
> > you to lunar orbit and/or heading back to Earth with a reasonable mass
> > ratio.
> The very best fuel on the Moon is obviously a linear motor/mass
> driver. One needs to make a ramp (using the best angle, which?)

No angle, makes your perigee the surface.

out of
> regolith/solar-oven made regolith glass bricks, and create a means of
> fabricating PV arrays (maybe just sputtering appropriately doped (made
> in situ or imported) silicon on lunar soil glass panes, which can be
> made by melting the surface of finely powdered regolith, giving time
> to anneal/cool and then simply lift them off the powder surface). I am
> not sure if lunar soil (without adding cryolith) is suitable for melt
> electrolysis, one can certainly use hydrogen (from polar ice)
> reduction to get at the iron (see according NASA papers).

heating regolith to about 600 deg C causes it to outgass its oxygen.

> Another nice point about a linear mass driver is that in the simplest
> implementation it is just a linear array of identical modules:
> solenoids, high-voltage capacitors and control logic (could be made as
> "vacuum tubes", as even process-contaminated vacuum is probably better
> than what is inside your CRT). Optimal for automated
> mass-production. With time doubtlessly different techniques will be
> developed: wet metallurgy, electron beam ovens, massively parallel
> preparative mass spectroscopy for separation, on the long run even
> nanotechnological methods, which would be obviously best.
> By firing 10 kg packets each minute it could put 14 t/day, or 5
> kT/year of material into orbit. And I guess these are very
> conservative estimates.
> What most astonishes me most is how little attention this angle of
> attack receives. Space simulator chambers are a lot cheaper than
> shooting the stuff in orbit to test. Also, Earth gravity arguably
> reflects lunar situation better than microgravity conditions (these
> will be necessary for asteroid processes though).

O'Neil's space colonization study was the opus on this area.

Mike Lorrey