Comparison of oxygen liquefaction methods for use on the surface of Mars

One of the specificities of exploring Mars is the tremendous mass of propellant necessary for the ascent from the planet's surface. Due to the large mass of the Mars Ascent Vehicle – the space shuttle to be used by astronauts to evacuate the surface of Mars in a future crewed Mars mission – and the resulting large quantities of propellant (generally oxygen and methane) required, it is more efficient to produce propellants in situ from the atmosphere of the planet.