>>11822056In real life?
Load water-bearing material (anything from crushed hydrated minerals to chunks of water ice) into a vacuum oven.
Use vacuum oven to recover water and temporarily store.
Split water in electrolyser to make hydrogen and oxygen; liquefy and store oxygen, temporarily store hydrogen.
Collect liquid CO2 from the atmosphere using a compressor, temporarily store.
Flow hydrogen and CO2 into a heated nickel catalyst reaction chamber, causing the hydrogen to reduce the CO2 to methane and water.
Compress and cool resulting gas mixture to separate the water (sent back to water storage) and methane (liquefied and stored) from the unreacted CO2 and hydrogen, which flows back around through the reaction chamber again.
Lion's share of energy draw comes from water electrolysis; reduction of CO2 using hydrogen is actually exothermic, so other than the initial heating of the catalyst that chemistry runs itself. The next biggest power draw comes from the various pumps and compressors necessary to do fluid handling. Again, a small amount of power compared to electrolysis.
The only required input resources are water and CO2, both readily available across the surface of Mars. Don't bother drilling for water, just dig trenches and quarries for permafrost and buried glacier ice. CO2 is obviously everywhere, in the atmosphere. Just need some filters to catch and remove airborne dust particles so they don't gunk up machinery.
