Small cryogenic propulsion unit for upper stage application

The feasibility study was conducted to use the cryogenic propulsion system for the third stage of the future H-1 vehicle. While the $\text{LO}{}_2\text{LH}{}_2$ third-stage mass fraction is less than the current solid propellant third stage, the 50% higher Isp results in a significantly higher payload. Two basic configurations of the new propulsion system were proposed: one pressure-fed system and two pump-fed systems. The first is a pressure-fed system providing a 700 kg thrust at an Isp of 441 sec with restart capability. The second is a pump-fed system, operating on an expander cycle principle. A midget turbopump with a 90 000 rpm shaft speed feeds the thrust chamber which delivers 1 ton of thrust at an Isp of 471 sec. The third proposed system is also a pump-fed design using a unique expander bleed cycle, and delivers a 1 ton thrust at an Isp of 470 sec with a turbopump speed of 80 000 rpm. The results of engine testing predict the performance feasibility of respective propulsion system designs.     

The dive and ascent satellite program for lower ionosphere research

Lower ionosphere is a transition region from outer-space to low atmosphere and had been unexplored on a continuous basis before Atmosphere Explorer satellites flew in the region. Purpose of a new aeronomy satellite, DAS (Dive and Ascent Satellite) having a capability to control orbits and flying at the very low perigee altitude less than 130 km is to explore the bottomside of ionosphere spreading over between 100 and 300 km altitudes. Preliminary study on the new aeronomy satellite is conducted at National Aerospace Laboratory in cooperation with Radio Research Laboratories and Meteorological Research Institute.This paper reviews the mission design, orbit decay and transfer analysis, typical orbit profile, aerodynamic characteristics and satellite configuration study, aerodynamic heating and thermal control analysis, attitude control analysis, on-board propulsion and power subsystems, and operation analysis with emphasis on their technical feasibility.     

Reorganization of the space development structure in Japan

At the end of 2002 a new law was passed to create a single space agency for Japan out of the merger of NASDA and NAL with ISAS. The new agency will be an independent administrative institution with day-to-day autonomy from the government. The authors provide the background to the decision to restructure Japan's space development and describe the goals, organization and scope of activities of the agency. Steps have been taken to counter concerns that consolidating the three existing organizations could hamper the conduct of basic research.