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Japanese X-ray astronomy satellite ASTRO-E2 named “SUZAKU“ was successfully launched on July 10, 2005. SUZAKU is the fifth Japanese X-ray astronomy satellite to observe X-ray coming from hot and active regions in the universe in collaboration with NASA GSFC, MIT and University of Wisconsin. “SUZAKU” has achieved the high sensitivity wide energy band X-ray spectroscopy than ever before. It is equipped with X -ray telescopes (XRT) and three kinds of focal plane instruments, X-Ray Imaging Spectrometer (XIS), X-Ray Spectrometer (XRS) and Hard X-Ray Detector (HXD). A radiation-cooling system, connected to XIS and HXD with heat pipes, is provided to cool them below −30 C and −20 C respectively. Furthermore, a side panel has a large cut out to expose XRS cryogenic Dewar for direct cooling. Flight temperatures indicate that the three sensors are kept below their cooling-requirement temperature.

The ISAS's space VLBI satellite HALCA was successfully launched in February 1997. The spacecraft HALCA consists of a box shaped main structure and a large deployable mesh antenna with 8 m effective diameter. The integrated spacecraft with the mesh structure antenna is so large and complex that the thermal design and tests had been performed separately for the main structure and the large antenna. No thermal vacuum test had been conducted in the fully integrated spacecraft configuration. The complex heat exchange between the antenna and the main structure had been taken into account in the numerical thermal analysis. Good correlation between in-orbit temperature and flight prediction has proved validity of the design and the verification method where no integrated spacecraft thermal vacuum test was performed.

The Advanced Land Observing Satellite “DAICHI” (ALOS) is the latest Japanese 4-ton class earth observing platform launched on January 24, 2006. The primary mission of DAICHI is obtaining enormous amount of data for global topographic maps and emergency disaster observation. It is equipped with three remote sensing instruments; the stereo mapping panchromatic imager, the multi-spectral radiometer and the L-band synthetic aperture radar. The thermal control of the DAICHI employed new technologies enabling highly accurate earth observation and gigabit per second mission data handling. A combination of passive and active control techniques stabilizes orbital temperature variation of the truss structure and a large optical bench for observing instruments within less than a couple of degree C. The bus structure is entirely made of low CTE and high thermal conductive pitch-based CFRP instead of conventional aluminum alloy.