[extropy-chat] Space elevator numbers III

Sat Feb 17 11:55:46 UTC 2007

On Fri, Feb 16, 2007 at 01:38:07PM -0500, Keith Henson wrote:

> Ok.  You are "there" at the lunar north pole in a centaur type robot.  I 
> even grant you finding water in some form.  What are you going to do?

I don't have a particular bootstrap scenario, because this is something
which needs to be tested in practice, in the lunar simulator. What I would
start with, however, is by setting up large parabolic mirrors from mylar
(whether inflatable, or spanned on a foldable truss structure), and melt
regolith in the focus to sheet glass (left in situ) and sputter materials
(not yet produced locally) producing large areas full of thin-film
photovoltaics. Once you have large local PV output, you can do things
like microwave processing, electron beam patterning and welding, and
ion beam patterning. Structural material would be fused glass (regolith
is good enough), spun glass, and metal (electrolytically prepared from
molten ore, might require low-melting salts as additives, but then,
if you've got a lot of power, being wasteful is not that large an issue
as long as you're in a bootstrap phase. What would be interesting in
how how much control logic you need, and whether you can write them
directly by ion and molecular beams onto substrate.

> Lunar rock is silicon, aluminum, iron (a little free state) and 
> oxygen.  The silicon and aluminum are tightly bound in complex oxides.  Do 
> you have any idea of the steps and chemicals needed to process such rock 
> into metals and very high purity silicon?

Yes. You don't need high purity silicon, because a 100 kg monocrystal
goes a long way, if sputtered onto glass in um layers. Initially.
There are several separation stages possible. Microsorting of the
regolith is possible. Hydrogen reduction (closed-circuit water electrolysis)
of regolith, and magnetic sorting. Electrolysis in the melt.
Fractional destillation. Preparative mass spectroscopy. About a dozen
other things I haven't thought of, but other people will. 

It's an experiment, where you improvise and invent along the way.
Because this is expensive, you have to scale down size, and do most
of the prototype work Earth-side, in lunar simulators. NASA has just ordered
a large batch of simulated regolith, and UHV chambers where you could
walk in are expensive, but not nearly as expensive as actually soft-landing
a kiloton of hardware on Moon surface.

There's a continuum between macroscale plants and nanoscale plants,
so a mesoscale tabletop plant can produce output, and can be scaled
up by replication. It's all about replication closure, not efficiency.

> Am I the only one on this group with industrial process experience?

Keith, you might have lots of industrial process experience, but I'm
pretty sure you have little to none industrial process experience where
UHV and energy glut are present, and you have to really strange things.

Nobody has such experience, because such processes have largely to be
yet to be developed.

> Please point out where I have put a price tag on this project.  I don't 
> think I have because I don't have any idea of what it would cost to build 
> or even the sub parts.

How many launches into high Earth orbit would it take to get to get your
material (counterweight and the carbon nanotube cloth belt) up? If the
counterweight is an asteroid, which specifically, and how much energy
is needed to capture it?

> Think of north sea oil.  The market is essentially the entire world energy 
> market.  Last year ExxonMobile's profit was $20 billion.  If there is a 
> clear case to make money, especially when it solves *major* problems such 
> as global warming, it shouldn't be hard to get it to happen.

It is pretty clear that there is a way to make much money from methanol
plants from coal and methane, and such plants are not all that expensive,
but the industry doesn't do it because it considers there's not enough
certainty, because the oil market is so volatile. If they're loath
to commit a lousy few hundred megabucks, what about few hundred gigabucks,
or a terabuck? I actually don't think a terabuck isn't all that unrealistic.
The Iraq shenanigan has so far cost 0.3 terabuck, and after the smoke
clears it might reach a terabuck yet. Isn't it quite obvious where our
priorities lie?

> I think we live an energy poor lifestyle right now.

I agree, but in terms of what you get for a unit of energy, we're
ridiculous. In a solid state civilization, given a liter of computronium
and an energy budget of about 100 W, the lifestyle is really really
really different. And you still get to play with the energy output of
a star, or more (assuming, the population is so high that a star is not
enough, and you have to start converting matter to energy on a very
large scale).

-- 
Eugen* Leitl <a href="http://leitl.org">leitl</a> http://leitl.org
______________________________________________________________
ICBM: 48.07100, 11.36820            http://www.ativel.com
8B29F6BE: 099D 78BA 2FD3 B014 B08A  7779 75B0 2443 8B29 F6BE
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 191 bytes
Desc: Digital signature
URL: <http://lists.extropy.org/pipermail/extropy-chat/attachments/20070217/1dcb23f3/attachment.bin>