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http://www.mines.edu/research/srr/LDEM_ … d.pdf]This study may be the current "state of the art" study on the economics of mining lunar water for rocket fuel.
Links to other studies are appreciated.
This study assumes mining water (assumed to be 1% to 2% of lunar regolith by weight) for purposes of making LH2 and O2. Large infrastructure is required.
Excess O2 is discarded.
Suppose we ignore the water and simply seek to extract O2 using less capital intensive means such as passive solar furnaces. The goal is NOT engineering efficiency but rather capital investment efficiency. Simple pyrolysis should extract massive amounts of O2 relatively easily. Transport O2 using methane or LH2 shipped from Earth and by-pass the whole hydrogen issue, at least to begin with.
Run the numbers again.
My intuition tells me that shipping LOX from Luna and methane or LH2 from Mother Earth to an LEO depot will result in the necessary rocket fuel being positioned in LEO at a lower net cost than shipping water from Luna to L1 for cracking into H2 and O2 and then shipping to LEO.
Far, far less capital investment as well since pyrolysis will allow O2 to be harvested with the most rudimentary of equipment.
Very much less regolith needs to be processed to extract O2 (fewer big machines!) and NO water cracking facilities at L1 or on the Moon.
Initial capital investment? Very substantially smaller than this study assumes.
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If water is produced during pyrolysis (as a minor by-product) well good! Save it and use it!
Also pyrolysis may be a useful step for extracting PGMs by reducing the mass of a sample before running carbonyl processing (Mond process) to further concentrate the PGM laden ore.
Extract O2 then extract iron, nickel, cobalt by Mond Process then smelt further to concentrate the PGMs even more then ship the ore to Earth to complete PGM extraction.
Give someone a sufficient [b][i]why[/i][/b] and they can endure just about any [b][i]how[/i][/b]
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A convient as it might be, I think it might be best if we save what little water there maybe/is for eventual settlement, however small it might be.
There is still ample O2 in the rocks, along with He3, heavy metals and PGMs. If we are really hurting for H2, capture an astroid or comet or two.
"Yes, I was going to give this astronaut selection my best shot, I was determined when the NASA proctologist looked up my ass, he would see pipes so dazzling he would ask the nurse to get his sunglasses."
---Shuttle Astronaut Mike Mullane
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Are we sure pyrolysis will drive off oxygen? I have not seen studies that assume that. Most assume it is easier to reduce ilmenite with hydrogen or use some other chemical process.
-- RobS
P.S.: I've seen this Colorado School of Mines report and commented on it in other threads. It is a very thorough study, and one that uses business models as well. The results are not very favorable for the use of lunar polar ice; it indicates that it would be difficult for a private business to make a profit off of it.
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A convient as it might be, I think it might be best if we save what little water there maybe/is for eventual settlement, however small it might be.
There is still ample O2 in the rocks, along with He3, heavy metals and PGMs. If we are really hurting for H2, capture an astroid or comet or two.
Actually, I agree with you.
In addition, in another thread, I asked about scooping up the regolith underneath where rockets launch from the Moon.
Combust LH2 or CH4 while ascending from the lunar surface and I suspect water ice and CO2 ice will fall like snow. Even if you recovered only 10% or 15% of the combustion products, its all gravy, right?
Pyrolysis links to follow.
http://adsabs.harvard.edu/cgi-bin/nph-b … ey=AST]One link
http://lifesci3.arc.nasa.gov/SpaceSettl … 1.htm]Link #2
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It appears heat is all that is needed except for running pumps and compressors and loading regolith into the hoppers.
Edit #2:
If we abandon engineering elegance as a target objective and send "too many" inflatable mirrors to concentrate sunlight there should be plenty of sunlight at least 14 days each month.
How much mass would a 100 square meter mylar mirror require?
Or even a 1000 square meter mylar mirror?
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Use the heated slag to run a rudimentary Sterling engine.
Forget elegance. Low capital costs are the criteria!
Edited By BWhite on 1111099666
Give someone a sufficient [b][i]why[/i][/b] and they can endure just about any [b][i]how[/i][/b]
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