Monomethylhydrazine

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Monomethylhydrazine

Systematic name	Monomethylhydrazine
Chemical formula	CH₃N₂H₃
Molecular mass	46.07 g/mol
Density	0.88 g/cm³
Melting point	-52 °C
Boiling point	87 °C
Heat of vaporization	875 kJ/kg
Vapor pressure	4.93 kPa (20 °C)
Vapor pressure	7.3 kPa (26.85 °C)
Vapor pressure	638.0 kPa (154.85 °C)
Specific heat	2,921 kJ/kg*K (20 °C)
Specific heat	3,077 kJ/kg*K (119,85 °C)
Dynamic Viscosity	0,855 * 10^-3 Pa * s (20 °C)
Dynamic Viscosity	0,40 * 10^-3 Pa * s (70,85 °C)
CAS number	[60-34-4]
Solubility	soluble in water, alcohol and ether
Disclaimer and references

Monomethylhydrazine (MMH) is a volatile hydrazine with the chemical formula C H₃N₂H₃. It is used as a rocket fuel in bipropellant rocket engines.

MMH is very commonly applied notably in the OMS (orbital maneuvering system) engines of the NASA "space shuttle" or STS. The compound is toxic and carcinogenic, but easily stored in space providing moderate performance for very low tankage and fuel maintenance system weight. Recently the European Space Agency has attempted to seek new options in terms of propellant/oxidiser combinations in order to avoid chemicals such as this.

MMH and its relative UDMH (unsymmetrical dimethyl hydrazine) have a key advantage that they are stable enough to be used in regeneratively cooled rocket engines.

It is also found in trace amounts in raw Agaricus bisporus, the common mushroom in grocery stores, and poisonous Gyromitra mushrooms, or "false morels".