A preburner is a secondary combustion chamber that burns a small portion of the propellants to generate high-pressure gas. This gas spins the turbines that power the engine's main propellant pumps before being routed into the main combustion chamber. By utilizing the exhaust from the turbine rather than dumping it overboard, engines with preburners achieve significantly higher efficiency and thrust.
Telemetry shows a pressure drop in the oxygen preburner just before MECO.
Do not mix it up with
- Gas generator: A preburner feeds its exhaust into the main combustion chamber, while a gas generator dumps it overboard.
Related terms
MECO
Main Engine Cut-Off is the moment during a rocket launch when the primary engines are commanded to shut down.
Gas generator
A gas generator burns propellant to create high-pressure gas that drives turbines or pumps.
Chemical rocket
A propulsion system that generates thrust through the exothermic reaction of chemical propellants.