The Methane and Carbon Monoxide/LOX rocket (MCLOX) is a technology for accomplishing ascent from Mars. Current Mars in-situ propellant production (ISPP) technologies produce methane and carbon monoxide in various combinations, but with neither generally produced in pure form. While separation and purification of methane fuel is possible, it adds complexity to the propellant production process and discards an otherwise useful fuel product. The MCLOX makes such complex and wasteful processes unnecessary by burning the methane/CO mixtures produced by Mars ISPP systems without further refinement. Despite the decrease in rocket specific impulse caused by CO admixture, the improvement offered by concomitant increased propellant density provides a net improvement in stage performance, and this mission advantage is amplified further by the increase of the total amount of propellant produced and the decrease in mass and complexity of the required ISPP plant. For these reasons the development of the MCLOX rocket is important to achieve maximum benefit from Mars ISPP systems.