  The Challenger disaster and purposeful experiments with liquid hydrogen (H2)
and oxygen (Ox) tanks demonstrated that cryogenic H2/Ox fluids always
self-ignite in the process of their mixing. Here we propose a
cavitation-induced self-ignition mechanism that may be realized under these
conditions. In one possible scenario, self-ignition is caused by the strong
shock waves generated by the collapse of pure Ox vapor bubble near the surface
of the Ox liquid that may initiate detonation of the gaseous H2/Ox mixture
adjacent to the gas-liquid interface. This effect is further enhanced by H2/Ox
combustion inside the collapsing bubble in the presence of admixed H2 gas.
