Which is the most widely used fuel-oxidiser combination in cryogenic rocket engines?
[A]Liquid hydrogen and oxygen
[B]Liquid hydrogen and nitrogen
[C]Liquid nitrogen and oxygen
[D]Liquid carbon dioxide and oxygen
Liquid hydrogen and oxygen
The combination of liquid hydrogen (LH2) fuel and the liquid oxygen (LOX) oxidizer is one of the most widely used fuel-oxidiser combination. Both components are easily and cheaply available, and when burned have one of the highest enthalpy releases by combustion, producing specific impulse up to 450 s (effective exhaust velocity 4.4 km/s). Reference