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Argos
2004-Apr-10, 01:57 AM
Some scientists have been wondering (and I rank with them in the questioning) how to extract ice from the Moon:

How to drill an abrasive and hard like steel ice pack?

How to make burs capable of withstanding extremely low temperatures?

How to work in an absolutely dark environment, in the bottom of steep craters, far away from any reasonable place for the establishment of a base?

Should this task involve humans?

tuffel999
2004-Apr-10, 03:37 AM
How to work in an absolutely dark environment, in the bottom of steep craters,

That is easy plug a light into the nearest power outlet duh #-o

Staiduk
2004-Apr-10, 03:40 AM
I guess the first question should be 'is there ice on the moon?' I remember that they detected signs that indicated ice around the Moon's south pole; but have they confirmed it?
If they have; I personally think mining ice wouldn't be that much of a problem - it'd just take a huge initial preparation and heartbreakingly hard physical work.
(This is assuming ice would be found in block form; not suspended as permafrost. The results would be similar; but a lot more work for less overall gain.)
You'd need to establish a self-sufficient base on or near the vein. Water would have to be brought; initially. Power could concievably be collected from panels at the nearest point where the sun is visible; but I'm just speculating. Heck; this is all speculation, innit? 'S why it's fun. :)
Anyhoo; once you had your base established; you could preseumably mine the ice with modified conventional tools; building enough stock to power the base itself. As to the specifics; modern tools and metallurgy could handle both the hardness of the ice and the low temperatures easily; and floodlights to handle the light. If the vein was in an area where a base couldn't be established; you'd need either surface transport - some kind of long-term work vehicle - or the Heinlein alternative of tunneling into the vein.
Obviously I haven't got a clue; I just love speculating about it - it's my favourite 'The Moon Is a Harsh Mistress' aspect. :)

Jigsaw
2004-Apr-10, 03:41 AM
Question: What would be the rationale for extracting ice from the Moon?

http://nssdc.gsfc.nasa.gov/planetary/ice/ice_moon.html

The estimated total mass of ice is 6 trillion kg (6.6 billion tons).
That's not a lot of ice.

That's about the size of a really huge iceberg.
http://www.thewe.cc/weplanet/poles/antarcti/iceshelv.html

The super iceberg B-15, weighing 2 billion tons, broke into a number of smaller pieces.
So, why is it going to be a good idea to dig up the equivalent of a really huge iceberg? Unless you're going to postulate "Heinlein-esque denizens of moon acquire water supply".

granolaeater
2004-Apr-10, 08:15 PM
Question: What would be the rationale for extracting ice from the Moon?

http://nssdc.gsfc.nasa.gov/planetary/ice/ice_moon.html

The estimated total mass of ice is 6 trillion kg (6.6 billion tons).
That's not a lot of ice.

That's about the size of a really huge iceberg.
http://www.thewe.cc/weplanet/poles/antarcti/iceshelv.html

The super iceberg B-15, weighing 2 billion tons, broke into a number of smaller pieces.
So, why is it going to be a good idea to dig up the equivalent of a really huge iceberg? Unless you're going to postulate "Heinlein-esque denizens of moon acquire water supply".

If you use the water as fuel for spaceships and use 1000 tons per launch you could do 6.6 million launches. Seems enough to me before you can get access to better water supplies in the outer solar system.

Anthrage
2004-Apr-10, 11:12 PM
How to work in an absolutely dark environment, in the bottom of steep craters, far away from any reasonable place for the establishment of a base?

Actually, as it happens, due to the same mechanism - the angle of the lunar axis - which allows the ice to (continue to) exist in the first place, there are areas in relatively close proximity to the location of the ice that are more favorable for a base than elsewhere. Shackleton crater is an area in which evidence of resources of hydrogen has been found. A section of the rim of this crater is illuminated or in 'daylight' for more than 75% of the lunar rotation period. This not only produces a less harsh thermal environment - about -60 to -40 degrees C. compared to the equator which is about -150 to -100 - but it provides the opportunity for near-constant pwoer generation from solar collectors.

Recent data has suggested however that while the deposits are definitely present, they are not (http://dsc.discovery.com/news/briefs/20031110/moonice.html) likely (http://www.astronomy.com/Content/Dynamic/Articles/000/000/001/565lyxln.asp) in the form of ice as is commonly envisioned. This will of course mean extraction or refinement will be more difficult than planned, but it is in no way impossible. It is an important and vital resource, and if there are any serious plans for a return to human activities - and a longterm stay - on the moon, it will be a very imporant factor.

By most informed accounts, Shackleton crater is one of the best sites for a multi-purpose lunar base. As such, hydrogen extraction operations or not, we will very likely have the opportunity to directly establish just want form the water deposits are in, fairly early on in such lunar endeavors. Once we know what form it is in and what the conditions are, we will truly begin to be able to answer questions about how possible or difficult extraction will be. With any luck, we'll have the answer within 2 decades.

gbaikie
2004-Apr-11, 12:59 PM
"So, why is it going to be a good idea to dig up the equivalent of a really huge iceberg?"

In order to land on the Moon for Apollo, the LM had to carry the fuel necessary to get off moon down to the surface. LM was a two stage vehicle- a descent vehicle and an ascent vehicle:
http://www.astronautix.com/craft/apollolm.htm
The total mass of LM was: 14,696 Kg. Descent vehicle weighted: 10,149 kg and Ascent Stage was 4,547 kg [2,358 kg of that is rocket fuel]. And about 2/3rd of the total mass of the LM was rocket fuel: 10,523 kg. If you already had fuel avaliable at lunar surface you wouldn't need to carry the return fuel all the way from Earth to the Lunar surface. So, with rocket fuel at lunar surface instead of LM weighing around 15,000 kg the LM with same payload capacity could weight about 5,000 kg- if it refueled at surface. Not only that but LH&LOX is a more efficent chemical rocket than the N2O4/UDMH used for Apollo LM [Isp: 311 sec compared to about 450 ISP for LH&LOX].
So roughtly your 5000 kg lunar lander need about 2500 kg in fuel to land on lunar surface and refilling at lunar surface it needs another 2500 kg of fuel to leave the Moon. If you are company making rocket fuel on the Moon, you not only have market for rocket fuel on the lunar surface, but you can also ship rocket fuel to Earth or Lunar orbit- so you could refuel the lander before it lands on the moon and when it needs to leave the Moon.
How much is lunar water worth at lunar surface? Well, you could say it's worth the cost of shipping it from Earth [currently at least $20,000 per kg] but instead let's say it's worth on average about $500 per kg- at this price it would allow significantly lower the cost of going to the Moon and allow shipping to rocket to lunar orbit and be competitive compared to shipping from Earth- and if you lower the cost of going to the Moon it will mean more people going to moon, allowing you sell more water. Now, they predict there is 6 billion tonnes of water on the Moon, let's say you can only actually mine 6 Million tonnes- at 1/2 million per tonne, that a gross value of 3 trillion- that's just the lunar water mining business, there is also need for electrical power [needed to split water into Hydrogen and Oxygen] which could gross in the trillions- just for making rocket fuel- there of course would be other consumers of electricity, and evenually leading to providing electrical power to markets on Earth.

Swift
2004-Apr-12, 01:27 PM
Lunar ice (http://www.americanscientist.org/template/AssetDetail/assetid/21888;jsessionid=baa_vW2YwSXOOD)
The link is to an American Scientist article I read a while back on lunar ice. Sorry you have to be a subscriber for the whole thing, but you can look at the abstract. If I remember correctly, their findings where that the ice at the poles is probably left over from impacts of comets. They believed that it did not exist as blocks or masses of ice, but mixed in with the "dirt" in the bottom of these craters. I don't remember if they estimated quantities, but I think the idea was that there may be substantial amounts, but it is highly dispersed.

Andromeda321
2004-Apr-12, 03:06 PM
Get a bunch of coal miners and get them to work. I assure you they'll do a good job plus you'll cut down on unemployment in Applachia!
Darkness is, in my opinion, one of the least of your problems because mining has never involved much light once you get down there. I'd worry more about the cold: if it was an area that never saw sunlight (as required for the water ice to exist in the first place) you would have very cold temps. That would require a lot of insulation for people working there when at the surface.
Of course, once you actually started digging in and made a mine you'd have a bunch of rock surrounding you which would be a fairly nice insulator for heating purposes. The other problem then would be if you put air into the mine: you would definetely need air circulation which is expensive enough on Earth.

wedgebert
2004-Apr-12, 04:08 PM
The temperature would be about the same as Lunar night. I don't think extreme cold is a problem. One of the major hurdles of working in space is how to shed excess heat, not how to deal with retain it.

Swift
2004-Apr-12, 05:27 PM
Even if there was enough ice to make mining worthwhile, particularly if it is dispersed, I can't imagine we'd send people in with picks and shovels. I would think it would be done by machine. Probably a little like a strip mine if it wasn't too deep. If it was deep, I would think you could extract it like natural gas - put a pipe down, pump some heat down (maybe hot air or nitrogen), melt and vaporize the ice, then extract the water out of the returning gas.

George
2004-Apr-12, 07:36 PM
The lunar ice trapped down in the southern craters which never receive sunlight will, likely, have sunlight along or just above their rim (depending on terrain). It would seem possible to easily make a simple reflector to direct a good portion of the Sun's 1,370 watts/sq. meter into the area for light, factility warmth and ice melting needs. Two reflector towers could provide twice the light as one during almost half of a lunar month. At least one would always be useable.