Having access to liquid oxygen (LO2) on the lunar surface is preferable to shipping it from Earth. Fortunately, the lunar surface is made up of a large quantity of O2. Unfortunately, the product is locked up in other material, in the form of aluminum oxide, silicon oxide, etc. Fortunately, there is a fairly simple process to extract O2 from lunar dirt.
Molten Calcium Chloride Salt Electrolysis
After mining the lunar surface (Image 1 and Image 2), the regolith is dumped into a chamber. The dirt is immersed in a 950o C bath of molten salt and electrocuted, allowing the oxygen to be released from its bondage, migrating to the anode of the device.
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| Image 2: Another version of LOX extraction operations |
It is estimated that this process can extract about 75% of the O2 in one day from lunar dirt that consists of 40% oxygen.
Once the O2 has been collected, the waste product happens to be metal alloys (Image 3) that can be set aside for future use, such as 3D printing of habitable enclosures.
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| Image 3: Before and after images of lunar simulant |
Liquifying Oxygen
The gaseous oxygen (GO2) must then be converted into liquid form. This process calls for pressurized GO2 passing through copper tubing immersed in liquid nitrogen (LN2), which happens to be colder than LO2. LN2 will have to be replaced periodically due to boiloff.
LO2 Distribution
The liquid oxygen will be stored in portable tanks that will be transported to the landers for LO2 tank refill. Once the tanks have been emptied, it is returned to the LO2 facility for refurbishment and reuse.
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