UDMH (Unsymmetrical Dimethylhydrazine) ((CH₃)₂NNH₂) is a hypergolic fuel propellant used as a fuel. Storable for years at ambient temperature. Typical ISP: 280–310 s (with NTO) seconds.
UDMH is a storable, hypergolic rocket fuel widely used in Russian, Chinese, and Indian launch vehicles. It ignites spontaneously on contact with nitrogen tetroxide or IRFNA oxidizers. UDMH offers better thermal stability and a lower freezing point than pure hydrazine, making it preferred for long-duration storage in launch vehicles and strategic missiles.
Developed in the 1950s for storable missile propellants. Used extensively in Proton, Kosmos, Long March 2/3/4, and PSLV/GSLV vehicles.
Storable, hypergolic, good low-temperature performance, stable in storage
Highly toxic and carcinogenic, lower Isp than cryogenic propellants, environmental hazard
