The V-2 rocket used hydrogen peroxide decomposed by a liquid sodium permanganate catalyst solution as a gas generator. This was used to drive a turbopump to pressurize the main LOX-ethanol propellants.[1] In the Saturn V F-1[2][3] and Space Shuttle main engine,[4] some of the main propellant was burned to drive the turbopump (see gas-generator cycle and staged combustion cycle). The gas generator in these designs uses a highly fuel-rich mix to keep flame temperatures relatively low.