Aerozine 50 is a 50:50 mix by weight of hydrazine and unsymmetrical dimethylhydrazine (UDMH),[1][2] developed in the late 1950s by Aerojet General Corporation as a storable, high-energy, hypergolic fuel for the Titan II ICBM rocket engines.
Aerozine continues in wide use as a rocket fuel, typically with dinitrogen tetroxide (N2O4) as the oxidizer, with which it is hypergolic.
In addition, UDMH is a more stable molecule; this reduces the risk of pure hydrazine decomposing unexpectedly, increasing safety and allowing the blend to be used as a coolant in regeneratively cooled engines.
The Titan's second stage exploded, and the W53 warhead landed 30 meters from the silo portal without detonating or leaking fissile material.
[4][5] According to John D. Clark, the propellant community disliked and ignored brandnames such as Aerojet's Aerozine, preferring its own jargon of engineering acronyms and nicknames.