MMH (Monomethylhydrazine) (CH₃NHNH₂) is a hypergolic fuel propellant used as a fuel. Storable for years at ambient temperature. Typical ISP: 280–310 s (with NTO) seconds.
MMH is a storable hypergolic fuel used primarily in spacecraft propulsion systems, including the Space Shuttle OMS/RCS and many satellite thrusters. It offers a better balance of performance and handling compared to hydrazine and UDMH. MMH has a higher density impulse than hydrazine and better shock sensitivity than UDMH.
Widely adopted for spacecraft propulsion in the 1960s–70s. Used in Space Shuttle orbital maneuvering system and numerous satellite propulsion systems.
Storable, hypergolic, good stability, slightly better Isp than UDMH
Highly toxic, carcinogenic, expensive handling requirements
