[ExI] Lunar dirt

[Eugen Leitl]

On Thu, Jan 06, 2011 at 06:21:14PM -0700, Keith Henson wrote:
> Will someone enlighten me about what remote manipulators on the moon
> are going to be doing?

The first task would be exploration and mapping of the south
and north poles. The second part would be building large scale
thin-film PV arrays to mine volatiles and to build more
thin-film panels, and then to expand the industry base
until you can build linear motor launchers. 
 
> You don't have a lot to work with; lunar dirt is about as far from
> useful objects as I can imagine.

http://en.wikipedia.org/wiki/In-situ_resource_utilization

...

It has long been suggested that solar cells could be produced from the materials present on the lunar surface. In its original form, known as the solar power satellite, the proposal was intended as an alternate power source for Earth. Solar cells would be shipped to Earth Orbit and assembled, the power being transmitted to Earth via microwave beams.[2] Despite much work on the cost of such a venture, the uncertainty lay in the cost and complexity of fabrication procedures on the lunar surface. A more modest reincarnation of this dream is for it to create solar cells to power future lunar bases. One particular proposal is to simplify the process by using Fluorine brought from Earth as potassium fluoride to separate the raw materials from the lunar rocks.[3]

...

On the moon, the lunar highland material anorthite is similar to the earth mineral bauxite, which is an aluminium ore. Smelters can produce pure aluminum, calcium metal, oxygen and silica glass from anorthite. Raw anorthite is also good for making fiberglass and other glass and ceramic products.[11]
Over twenty different methods have been proposed for oxygen extraction on the moon.[4] Oxygen is often found in iron rich lunar minerals and glasses as iron oxide. The oxygen can be extracted by heating the material to temperatures above 900 °C and exposing it to hydrogen gas. The basic equation is: FeO + H2 → Fe + H2O. This process has recently been made much more practical by the discovery of significant amounts of hydrogen-containing regolith near the moon's poles by the Clementine spacecraft.[12]
Lunar materials may also be valuable for other uses. It has also been proposed to use lunar regolith as a general construction material,[13] through processing techniques such as sintering, hot-pressing, liquification, and the cast basalt method. Cast basalt is used on Earth for construction of, for example, pipes where a high resistance to abrasion is required. Cast basalt has a very high hardness of 8 Mohs (diamond is 10 Mohs) but is also susceptible to mechanical impact and thermal shock[14] which could be a problem on the moon.
Glass and glass fibre are straightforward to process on the moon and Mars, and it has been argued that the glass is optically superior to that made on the Earth because it can be made anhydrous.[11] Successful tests have been performed on earth using two lunar regolith simulants MLS-1 and MLS-2.[15] Basalt fibre has also been made from lunar regolith simulators.
In August 2005, NASA contracted for the production of 16 metric tons of simulated lunar soil, or "Lunar Regolith Simulant Material."[16] This material, called JSC-1a, is now commercially available for research on how lunar soil could be utilized in-situ.[17]

...
 
> I have followed this topic since the mid 1970 and, far as I know,
> there was never a believable flow chart with rock going in and useful
> stuff coming out the other.

Keith, I thought your knowledge of chemistry and geology was
better than this. The Moon has the added advantage of free UHV,
which would be expensive on Earth. Many processes can run in
dry UHV, and you will use gases and liquids only where necessary.
The important thing is that there's plenty of volatiles. That
changes the game. It's much easier now.

Add close to 24/7/365 insolation (eventually, you will build
rings around the poles, and this is excellent place for an
industry. About the only pollution problem is fouling up
your vacuum.
 
> Take solar cells.  Anyone have an idea of what sort of plant it takes

I have a very good idea of that, yes. I've even toured the facilities.

> make silicon?  What inputs the plant takes?  What has to be frequently
> replaced?

Current CdTe takes about 10 g/m^2. That's 100 m^2/kg. 10^5 m^2/ton.
At 10% and 1.3 kW/m^2, that's 13 kW/kg, 1.3 MW/100 kg, or 13 MW/ton.

Assuming you deliver 100 kg packages, each will be good for over
a MW of power.

-- 
Eugen* Leitl <a href="http://leitl.org">leitl</a> http://leitl.org
______________________________________________________________
ICBM: 48.07100, 11.36820 http://www.ativel.com http://postbiota.org
8B29F6BE: 099D 78BA 2FD3 B014 B08A  7779 75B0 2443 8B29 F6BE