Gas-generator cycle
From OrbiterWiki
The Gas-generator cycle is a common cycle used for pump-fed rocket engines. It uses one or more gas-generators for driving one or more turbines, which power the turbopumps to bring the propellants from tank head to injector pressure. The exhaust of the gas-generator is vented over-board and is not used for propulsion.
This cycle has the advantage of being very simple to design and operate, but is getting very ineffective for higher chamber pressures.
