Re: SPACE: Lunar Billboard?

Eugene Leitl (
Sat, 4 Jan 1997 14:15:00 +0100 (MET)

On Sun, 29 Dec 1996, Sean Morgan wrote:

> Michael Lorrey <> wrote:
> >The big difference between lunar colonies and say northern Canadian
> >mines is that it will still be more expensive to shuttle people around,
> >and since the resources come from there, your management and support
> >infrastructures will be permanently assigned, so they will start it, and
> >as they have kids, the population will expand.
> My point is that the resources won't come from the Moon. Aluminum, silicon,
> titanium, oxygen (though it's *very* tightly bound -- ever tried breathing
> rocks?), and that's about it. The bounty is in the asteroids, and better to
> leave them in orbit.

Moon differentiated allright after accretion, whether it happened on its
own, or while it has been part of the Earth. Al, Si, Ti (8% in some
specimens!) and O are merely the more common elements, the Moon contains
everying the Earth does (but in different ratios). It has equivalents of
Earth's gabbro, basalt, etc., and that's all it is needed. Light elements
(especially O/H from water, and complex organics) are expecially abundant in
carbonaceous chondrite, which is not present on the Moon (it was cooked
during differentiation, and carbonatios chondrite meteorites are
denaturated upon impacts, which applies much less to the iron/nickel ones).

What do you need oxygen for? It will be a waste product of element
production (which oxide you use is pretty the same in terms of energetics),
and machines do not need oxygen, for reaction mass merely, maybe. A
von-Neumann probe does not need humans to operate, maybe shipping and
installing essential 'vitamins' (dies) now and then. Sophisticated
autoreplicating technology does not even need that, being fully
autonomous/autarc. You can even produce 3d circuitry with beam writers,
if you only willing to wait. I doubt cicuitry producing processes will be
bottleneck, anyway.

Producing glass for substrate, metals for wiring/reflective coating,
silicon for photovoltaics, etc. are extremely energy-intensive processes.
Even if we minimize the bulk (to maximize autoreplication rate), the
growth will still be slow.

> As far as we know, ore concentration processes (biological, water,

Ah, vulcanists vs. neptunists, again. Biological processes are less
relevant, if you're not interested in hydrocarbons, water is not
interesting, as well. Metals, glass, and silicon (and a thimblefull of
more rare elements) should be sufficient for an autoreplicator.

You can't use tellurian processes in vacuum, anywere. It is
complementary: what is hard here, is easy there, and vice versa.

> tectonics) never happened on the Moon, so one shovelful of dirt is as good
> as another. Teleoperated earthmovers should suffice for "mining" equipment.

Not, so, the "dirt" is pretty heterogenous. Teleoperation is nice, but
second-long lags should be extremely annoying to human operators. I've never
tried, though, so one might adapt to it, with use. Sending people into
space is extremely wasteful, imo. I think skipping manned spaceflight
altogether, progressing immediately to the upload stage should be much more
profitable in terms of roi.