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

Andrew Yee (or somebody else of the same name) wrote thusly in message
:

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.

Why is this being called an "anomaly"? Surely "fault" or "cockup" would be a
better description? Or would that imply that somebody is to blame?

--
A couple of questions. How do I stop the wires short-circuiting, and what's
this nylon washer for?

Interchange the alphabetic letter groups to reply

Andrew Yee wrote:


snip

Don't put too much time into it.

It probably leaked; either the enclosing material was inadequately
designed [intrinsically unable to perform], inadequately formed
[production methods and tolerances] or a leak "developed" in space
[probable impact].

Bring it back to forensics or else get those shuttle boys and girls do
something else besides servicing those dodgy tiles the next time they're
up there.

M.