DEVELOPMENT STUDY OF LOX/LH2 PROPULSION SYSTEMS

ABSTRACT The national development program of a LOX/LH2 propulsion system, which is intended to be used as the second stage of the future Japanese launch vehicle called H-1, is being performed cooperatively by the three representative organizations relating to rocket technology in Japan: the National Space Development Agency of Japan (NASDA), the National Aerospace Laboratory (NAL) and the Institute of Space and Aeronautical Science (ISAS), University of Tokyo. The development study of LOX/LH2 propulsion system has started at the ISAS in 1975 according to its own program. By 1980 have almost finished the development tests of major components for the engine of 7,000 kg thrust level. The thrust chamber is of the tubular wall type and has the nominal design performance of 7,000 kg thrust level and 433 seconds specific impulse in vacuum. The gas generator is of the side-outlet reverse-flow type and composed of a spherical combustion chamber, 12 coaxial injectors and a start valve. The turbopump has the very unique configuration to have never been developed for rocket engine. A LOX and a LH2 pump are arranged at each end and a turbine at center of the turbopump. Each of the two pumps is mounted on each of the two rotor shafts which is not interconnected and rotate in opposite direction of each other because of no stator between two rotors. The solid propellant gas generator is used for the turbine spinner. The engine system assembled together with these components is to be tested in the middle of 1980. In parallel with the development of tubular wall thrust chamber, the channel wall thrust chamber is also being developed in the ISAS to aim at the future high performance engine, which is manufactured with use of the diffusion bonding technique. The present paper describes the status of the development study on the LOX/LH2 propulsion system being conducted by the ISAS.