MIT Professor Sadoway believes we can make oxygen anywhere on the moon with Molten Oxide Electrolysis (see here and here).

Let's assume that you need to make enough oxygen to sustain an astronaut for 24 hours. You need to make this amount of oxygen in about 8 hours.

If this can't be done, what is the minimum amount of time it would take to produce that much oxygen and how much equipment would this require?

If you believe there is another method besides Molten Oxide Electrolysis that can accomplish this, you are free to suggest it.

  • $\begingroup$ There's no point in specifying the time frame. The issue is how much equipment per astronaut. $\endgroup$ Commented Sep 10, 2015 at 0:05
  • $\begingroup$ @LorenPechtel I just want to know for one astronaut in this case, and the time frame would matter since I want the amount of oxygen needed for 24 hours stored in advance. $\endgroup$
    – called2voyage
    Commented Sep 10, 2015 at 15:06
  • $\begingroup$ Presumably he has some oxygen available, all that matters is that the production rate is faster than the consumption rate. $\endgroup$ Commented Sep 10, 2015 at 15:26
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    $\begingroup$ So long as the cycle length doesn't exceed his oxygen storage it doesn't matter if it's continuous or batch production. $\endgroup$ Commented Sep 10, 2015 at 18:36
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    $\begingroup$ Those papers are pure gold for me for the fuel production aspect. I've looked for this topic before without coming across Sadoway's work. Thanks for the find :) $\endgroup$
    – kim holder
    Commented Sep 12, 2015 at 1:48

1 Answer 1


You need to make 550 liters of oxygen in 8 hours. On average in the paper provided they made about 400 milliliters of oxygen per hour (throwing out the high and low outliers). That's 3.2 liters per 8 hours. At that rate you'd need 171 times more equipment than they had for this test to make this work.

They also burned through their electrodes quite often, so you'd need a large supply of these or a way to re-coat them locally.

I'd estimate the equipment weighs between 10 and 25 kg. You've got two crucibles as well as heating elements and insulation. You'd get some economy of scale so you'd need between 855kg and 2,000kg per astronaut, assuming a 100% increase in efficiency.

You could also look at CO2 photodissociation. There's been recent research in using ultraviolet light to fully strip CO2 to C and O2. It could be more efficient and simpler; however it is recycling vs adding new oxygen to the environment so that may not fit your criteria.

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    $\begingroup$ Great start to working out the answer. I'm sure the equipment would probably be configured differently for production of this scale, but just as a reference point how much weight would you figure their original test equipment was? It seems to be relatively small to me. $\endgroup$
    – called2voyage
    Commented Sep 17, 2015 at 19:52
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    $\begingroup$ It's not stated in the paper but I would guess between 10 and 25 kg. You've got two crucibles as well as heating elements and insulation. You'd get some economy of scale so I'd guess you'd need between 855kg and 2,000kg per astronaut. I'm assuming 100% increase in efficiency with scaling. $\endgroup$
    – Nathan
    Commented Sep 17, 2015 at 20:11
  • $\begingroup$ Would you mind working this comment into the answer? I think this is basically all I need in an answer. $\endgroup$
    – called2voyage
    Commented Sep 18, 2015 at 13:35
  • $\begingroup$ Since volume increase by power of three, would you really need 171x more stuff? Also, does that include a Lunar power source? $\endgroup$
    – RonJohn
    Commented Jul 17, 2023 at 21:09

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