LOXmethane

LOXmethane, or LOX/LCH4, refers to a liquid rocket propellant combination in which liquid oxygen acts as the oxidizer and liquid methane serves as the fuel. This combination has gained prominence in modern rocketry as a candidate for reusable launch systems and deep-space missions due to its balance of performance, practicality, and potential for in-situ resource utilization on Mars.

Compared with kerosene-based propellants, methane combustion tends to produce less carbonaceous residue, reducing engine coking and simplifying engine reuse. It also offers a competitive specific impulse and a manageable cryogenic regime. The typical oxidizer-to-fuel mass ratio for LOX/LCH4 engines is in the range of roughly 2.5 to 3.0, though exact values depend on engine design. Methane can be produced from carbon dioxide and water, enabling potential in-situ propellant production for interplanetary missions.

Storage and handling require cryogenic tanks for both LOX and methane, with careful insulation and leak prevention. Methane is flammable and constitutes a potent greenhouse gas if released, so leakage control is an environmental concern. Material compatibility and boil-off due to logistics pose engineering challenges for launch vehicles.

Historical interest in LOX/LCH4 dates to mid-20th century, with renewed emphasis in the 2010s and 2020s. It has been adopted in several contemporary propulsion programs, notably SpaceX's Raptor-derived engines for Starship and Blue Origin's BE-4, among others.

Outlook: LOX/LCH4 is widely discussed as a path toward reusable launch systems and Mars missions, and research continues to optimize engine performance, reliability, and propellant handling.