Well there's likely to be surplus rocket fuel available, either RP-1 (kerosene), methane, or liquid hydrogen, and LOX, so burning some in an (non-rocket) intern

Well there's likely to be surplus rocket fuel available, either RP-1 (kerosene), methane, or liquid hydrogen, and LOX, so burning some in an (non-rocket) internal combustion engine is not so crazy. Fuel cells would be more efficient though.