Lunar Solar Power Stations vs. The O'Neill Proposal

On 02/06/06, Combs, Mike wrote:
> One of the things Criswell quoted back from the GD-Convair study (and
> apparently what he uses for his comparisons) which didn't quite sound
> right to me is that in a comparison of Earth-launched SPS vs.
> lunar-derived SPS, costs were pretty much the same for the first 30
> satellites, and that beyond that there was a slight price advantage for
> the lunar resources option. I would rather have expected that use of
> lunar resources would have made the first 30 satellites more expensive,
> but beyond that point would achieve major cost reductions.

Earth launch options critically depend on how much it costs to launch.
Early studies by NASA were trying to find a use for the Shuttle, which
should be clear is a fairly expensive launch system. The numbers came
out pretty high with the Shuttle. (Gee, do you think?) I'm not sure
whether that's what the GD-Convair study did too.

O'Neill tried to finess around that by using lunar resources; and
Criswell is doing much the same trick.

I think in the long run that O'Neill's idea is good, and Criswell's
option is even cheaper, but people care more about short term costs,
even if long term costs are higher. They also care about risk even
more so.

I think the lunar resource options are higher risk, because you have
to be able to process the lunar material, and that's very researchy
thing right now. Also the mass driver can be done on paper, but
whether it would work when you scale it up, and stick it in a vacuum
and so forth is not clear. Well, it can definitely be made to work,
but I wouldn't like to bet that some of the first attempts don't blow
themselves to bits if the alignment is a bit off or something; or
otherwise fail the first few times.

There's clearly risk whenever you do something new for the first time.
And installing mass drivers on the moon isn't obviously easy-
presumably you would have to import most of the electronic components,
and assemble them there, you might be able to construct coils from
aluminum or calcium. But nobody has done anything like that, ever.
(Noteably, Moon dust is abrasive as hell, and destroys space suits in
a few hours.... little problems like that.)

>From earth launch perspective the numbers I've worked suggest that
expendable Falcon I's launched a *lot* (and I *really* mean a lot)
would bring the wallplug costs down to about $0.05/kWh, but I'm not
very happy with that option (Falcon I is too small to launch people
on, so a dirt cheap Falcon I wouldn't do much for space access, is
cheap, reliable electricity enough of a goal on it's own if it doesn't
lead to space colonisation????)

> Mike Combs

--
-Ian Woollard

"Gravity is just a theory. We shouldn't be teaching it to children as
if were fact."