Sabatier/Water Electrolysis Process

Schematic of Methane production system for a Single SpaceX Starship over a period of two years.Electrolysis and hydrogen storage are off the shelf. Sabatier reactor needs to be developed.

The Sabatier reaction is used to convert Hydrogen shipped from Earth or processed from Martian water-ice and Carbon dioxide from the Martian atmosphere to create water and methane for use as a fuel, which can be converted to Hydrogen. This fuel will generate more thrust per unit mass than hydrogen.

CO₂ + 4H₂ → CH₄ + 2H₂O -165 kJ/mol

The forward reaction takes place in the presence of high temperatures and pressures, in the presence of a nickel catalyst. Instead of nickel, a catalyst made out of ruthenium or alumina could be used.

The Sabatier process produces a ratio of 4:1 of oxygen to hydrogen, slightly more than the ratio used for propulsion 3.6, to 3.8:1. Excess oxygen can be used for the colony atmosphere os stored for future use.

If nickel is produced in-situ on Mars, additive printing could be used to prepare replacement electrodes for the Sabatier process

See Also

• Hydrocarbon Synthesis
• Bosch process