Staged Combustion Cycle

The staged combustion cycle, also known as the topping cycle, preburner cycle or closed cycle, is a power cycle used in bipropellant rocket engines in which propellant flows through multiple combustion chambers and is combusted in stages. Typically propellant first passes through a preburner, where a small portion is partly combusted under non-stoichiometric conditions to increase the volume of flow driving the turbopumps that feed the engine, before the resulting gas is injected into the main combustion chamber and combusted completely with the remaining propellant to produce thrust. Its main advantage over other rocket engine power cycles is high fuel efficiency, measured through specific impulse, while its main disadvantage is engineering complexity.