The Infrared Telescope in Space (IRTS) was one of the scientific experiments onboard the Space Flyer Unit (SFU). It was a 15-cm telescope cooled by superfluid helium. The mission purpose was high-sensitivity survey of the infrared sky. The IRTS experiment was successfully completed and brought important results for various astronomical issues, such as the composition of the interplanetary dust, the composition and physical condition of the interstellar matter, late-type stars, galaxy evolution and so on. The instrumentation of the IRTS, its flight operation, and scientific results are reported.

View full abstract

Biological effects of gravity were examined for early development of the Japanese red bellied newt, Cynops pyrrhogaster. Female newts were sent to space on Space Flyer Unit. Egg spawning was induced by raising temperature in orbit. Image of egg was obtained after newts were waked up from hibernation. The developmental stage of embryos at the end of space experiment was between morula and tail bud. Morphology of embryos was not deviated from those developed on ground.

View full abstract

The Exposed Facility Flyer Unit (EFFU) was one of the onboard experiment systems of the Space Flyer Unit (SFU). The purpose of EFFU was to obtain positive proof of the design and examine the basic function of the Japanese Experiment Module - Exposed Facility (JEM-EF). JEM-EF is one of the modules to be established to the International Space Station (ISS). On the EFFU, four onboard experiments were performed, Fluid Loop Thermal Control system (cooling system using fluid coolant perfluorocarbon) test to simulate the thermal control system of JEM-EF, experiment for Equipment Exchange Unit to simulate a toggle-link mechanism to hold and release for payloads exchange in the JEM-EF, Micro-gravity Environment Measurement to establish base data for micro-gravity aboard JEM and Materials Exposure Experiment in low Earth orbit environment to evaluate JEM construction materials in an orbit similar to JEM’s. All experiments were successfully completed and provided basic data for the design of space station elements as well as the future satellite. This paper presents major post-flight analyses and their evaluation results obtained from the above four experiments of SFU/EFFU mission.

View full abstract

An MPD (Magnetoplasmadynamic) arcjet system was assembled as a quarter-scale model of 1 kW thruster system dedicated to 3-million-shot endurance verification and to ground verifications such as mechanical, thermal and other environmental interface tests. It was installed on the SFU (Space Flyer Unit) launched on March 18, 1995 and tested as EPEX (Electric Propulsion Experiment) in space. All the system functioned properly and successfully demonstrated its propulsive function with hydrazine propellant. The system accumulated on/off cycles in space reached 43,395 pulses with misfirings of only 0.3 % during the several-day of assigned experiment period. The electrical power unit consisting of a single-staged capacitor bank was driven by the solar array. The generated thrust measured in space and the idealized specific impulse corresponding to 1,000 sec capability for full 1 kW system were also estimated to be the same as those obtained in the ground test.

View full abstract