Hydrazine (N2H4) (N₂H₄) is a hypergolic fuel propellant used as a fuel (or monopropellant). Storable at room temperature for years. Typical ISP: 220–240 s (monopropellant), 280–310 s (bipropellant with NTO) seconds.
Hydrazine is a highly reactive, toxic, storable liquid propellant used extensively in spacecraft attitude control and orbital maneuvering systems. It can be used as a monopropellant (decomposed over a catalyst) or as a bipropellant fuel with an oxidizer. Despite its extreme toxicity, hydrazine’s reliability, storability, and consistent performance have made it indispensable in space operations for decades.
Used since the 1950s in military and space applications. Remains the dominant monopropellant despite decades of effort to find safer alternatives.
Storable, hypergolic ignition (no igniter needed), reliable, high-density impulse
Extremely toxic, carcinogenic, requires SCAPE suits for handling, expensive safety measures
