DEVELOPMENT OF JAPANESE H-I LAUNCH VEHICLE

Abstract

The most advanced attempt towords the development of an expendable launch vehicle now in Japan is the H-I launch vehicle. The H-I launch vehicle is planned to be completed by the winter of 1985. After two tests flights it will be available for the payload users. The capability of H-I launch vehicle is to send 500 kg or more useful payload into a geostationary orbit from Tanegashima Space Center (TSC). The highlight of the H-I launch vehicle is a cryogenic LOX (Liquid oxygen)/LH2 (Liquid hydrogen) second stage with an inertial guidance system. The second stage propulsion system is equipped with 10 ton-f thrust (at altitude) regeneratively fuelcooled tubular thrust chamber. A gas generator cycle is adopted and LOX and LH2 pumps are driven on separate shafts-2 turbines in series. This engine has a restart capability and thrust and mixture ratio are controlled to ensure the high performance. While, the guidance system is a four gimballed stable platform type inertial guidance with self inertial alignment capability. This report covers the historical background, the result of feasibility studies, a total vehicle configuration, preliminary designs and development plans. Details and development status of major subsystem such as a second stage propulsion system, a guidance and control subsystems are included.