Re: New space settlement article

From: Sander Vesik (sander_at_haldjas.folklore.ee)
Date: 06/29/04 

Date: Tue, 29 Jun 2004 00:48:24 +0000 (UTC)

Mike Combs <mikecombs@nospam.com_chg_nospam_2_ti> wrote:
> "Sander Vesik" <sander@haldjas.folklore.ee> wrote in message
> news:1088112445.957295@haldjas.folklore.ee...
> >
> > Null hypothesis:
> > to cost the same per kW/h generated, the energy cost of a solar panel
> > and its support structure must be more than launching it from Moon
> > and de-accelerating it to GEO/HEO orbit.
> >
> > as any location of moon gets light 50% of time, you need 2x more solar
> panels
> > to generate the same power. Assuming we only care about solar panels and
> their
> > support structure, if launching from moon and de-acceleration to GEO / HEO
> > costs more in energy than just making a second panel, then you are better
> off
> > if you don't launch.
>
> A bit more than 2x, since lunar surface arrays would not always be able to
> point at the sun optimally, but that's nit-picking and I take your point.
>
> > If lunar aluminium extraction is as efficent as that on earth, getting
> > aluminium from Moon to the SPS location should not cost more than
> 16KWh/kg,
> > assuming 100% less efficent, 32KWh/kg. and thats payload mass.
>
> But there are other factors, such as the fact that if we do the ore
> reduction and materials proceessing in HEO, we can have continuous
> operation, due to continuous availability of solar power. Cheaper
> electrical costs due to solar availabilty should factor into construction
> costs as well.

But is constant availability of power needed? If not then it essentialy
controls only processing speed assuming equally powerful power sources.
With double, again, Moon loses nothing. You may save that (and more)
from simply not launching regolith and processing it instead.

>
> > Exporting
> > regolith (that is, doing teh smelting in earth orbit) is at least six
> > times worse.
>
> I assume you're saying this since it would be 6 times the material to
> process. But consider that there will be all kinds of useful materials
> coming out of the lunar ore, such as oxygen. Even the leftover slag will be
> usefull as radiation shielding.

This may be so, but its not a given. The problem is twofold:
        * the enrgy cost of extracting extra materials from the slag
        * the ability to put such materials to productive use

I don't think this is a well-explored (or explored even) area at all.

Additionaly - you can run all the same processes on Moon, and again simply
launch a fraction of the mass of regolith, except with all the profitably
recoverable components separated. As you are launching less, so is per-kg
cost of the materials less. I don't really see any way around that.

Not only that but as regolith is aboundant, you might not re-process the
slag but use a new, special process for every component you want starting
from sratch from regolith. Because its local and cheap.

>
> > If using aluminium based solids, consider propellant to payload fractions.
>
> No, I'd be the first to agree that the plan wouldn't be practical with this
> or any other variety of rocketry. It's only practical assuming EM launch
> with capture at the L-2 point.
>
> > Fine, but all teh materials for the mission are coming from moon. So why
> not
> > also build everything on moon and have the crew redezvous with their deep
> space
> > vehicle in moon orbit? Why spend all teh energy to move teh large ship (or
> > materials and consumables for it) to earth orbit and then away again? Why
> not
> > move a small capsule with the crew instead?
>
> Not all of the materials would come from the moon; some percentage would
> come from the Earth. One would have to strike a balance based on the two
> issues. I was thinking HEO only because I was thinking about utilizing
> infrastructure which was already set up there for other purposes, such as
> the construction of SPS and orbiting habitats. But if HEO is too far down
> the gravity well in your opinion, then I'd recommend the Earth-moon L-1
> point as the staging area. That's well out of both gravity wells, and one
> can do a boost maneuver around the Earth on the way out.

Besides preceison instrucments and crew and (with a caevat, food) all of
it could basicly be coming from Moon. It appears to be heavily balanced
towards Moon or at least Moon orbit.

>
> > Fine - its hard to argue that there will never be such. Whetever it
> arrives
> > before or other industry on say Moon is another matter, one that is not
> quite
> > that clear.
>
> I base my opinion on the sole studies that NASA ever did on industrial use
> of space resources. They suggested that lunar surface industry would only
> happen when there was a requirement for products whose end use was on the
> lunar surface.

I simply don't see the case of export regolith for processing off-moon. Even if
the "industry" is in earth orbit and the metal bending and casting happens
there I still don't see why you would want to export regolith from moon.
The sole exception to that would be if you used it for shielding so you only
cared about mass (and even so you might export the slag instead). just export
standard-sized bard / ingots of metal. this will also help create raw metal
supplier side competition.

maybe the study was unfairly biased by NASA's desire to be funded for operations
in Earth orbit?

Then again - I am certainly balanced towards Moon as the initial location for
off-earth mining and industry. But I don't claim impartiality. 

-- 
	Sander
+++ Out of cheese error +++

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