Booster-sustainer rocket engine and method

Abstract

A bi-propellant self-contained propulsion system is provided for powering rockets. A plurality of turbopump assemblies are provided to take liquid propellants from low pressure storage tanks to a substantially higher pressure thrust chamber. Substantially all of the liquid propellants are pressurized and gasified within the plurality of turbopumps. Substantially all of the gasified propellants are then used to drive the turbopumps that pressurize the liquid propellants. Gasification preferably occurs within a preburner internal to the turbopump assembly that combines a small portion of one of the propellants with a substantial portion of the other. The proportions are selected so that gasification of all of the propellants is ensured yet relatively low preburner temperatures are maintained. A multi-stage pintle assembly may be provided to vary the exit-to-throat area ratio of the nozzle. The total thrust and the mixture ratio may be controlled by shutting down some of the turbopumps. Actuation of the pintle is preferably coordinated with the shutting down of turbopumps to maintain a relatively constant thrust chamber pressure. A nozzle skirt insert is provided to enhance the low altitude performance of the rocket engine and the high altitude performance of the rocket engine.