Anomaly with the Suzaku Onboard Equipment XRS (Forwarded)

Japan Aerospace Exploration Agency
Tokyo, Japan

August 9, 2005

Anomaly with the Suzaku Onboard Equipment (XRS)

The Japan Aerospace Exploration Agency (JAXA) has been carrying out
initial operations of the "Suzaku" including turning on the observation
equipment after completing the solar array paddle deployment, three-axis
control mode establishment, and X-ray telescope extension. On August 8,
JAXA found the following anomaly in one of the three sets of onboard
observation equipment, the X-ray Spectrometer (XRS), which was developed
in cooperation with NASA and other organizations. JAXA launched the
Suzaku, the 23rd scientific satellite (ASTRO-EII), at 12:30 p.m. on July
10, 2005, Japan Standard Time (JST), from the Uchinoura Space Center.

The XRS is structured to cool down its X-ray micro-calorimeter (or the
detector) through freezing to the absolute temperature of 60
milli-degrees (or minus 273.09 degrees Celsius) for its operations. The
freezer is further wrapped by liquid helium and solid neon. In the early
stage, the cooling equipment was smoothly prepared for the operation,
and the detector successfully reached 60 milli-degrees, which is a world
record for a low temperature, and X-ray spectrum performance was
verified as being scheduled. However, on August 8, we found that all
loaded liquid helium had evaporated. As a result of this anomaly, the
detector cannot be cooled down; therefore, the scheduled observations
will be very difficult to carry out. The cause of the anomaly is
currently under investigation.

The other onboard observation equipment is in good shape and under
preparation. It will be ready for observations soon.

For the X-Ray Spectrometer, please see the attachment at
http://www.jaxa.jp/press/2005/08/img...ku_pic01_e.jpg

About Suzaku(ASTRO-EII),
http://www.isas.jaxa.jp/e/enterp/mis...e2/index.shtml