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FO-29 status, 7 Aug 2007

JARL report about FO-29 (Fuji-3) status and operation, 7 Aug 2007

The inside impedance of battery in FO-29 (Fuji-3) are rising now extremely
by deterioration at time. According to the telemetry data and the eclipse
rate of the satellite main body (the rate that a day is not), 25 minutes
are supposed with a limit as for the analog battery system use. Because
the eclipse rate of current FO-29 (Fuji-3) is about 30%, the power supply
of the relay with the battery cannot serve a period of the eclipse.

And the malfunction occurs in the part of the electricity control system.
The malfunction to become the problem in use in particular is UVC which is
an automatic function about the electricity management. When the satellite
is in the eclipse, and the light of the sun is not the solar battery, the
transmitter becomes OFF by UVC. It is designed afterwards so that an analog
system transmitter becomes ON automatically when the terminal voltages of
the battery exceed the rated value after the light of the sun is the solar
battery. However, it is likely that malfunction occurs for this function,
and the terminal voltage cannot turn on a transmitter even if it exceed
the rated value unless we send a command from the ground.

The eclipse rate of FO-29 (Fuji-3) will rise in future and rises to 34%
in March 2008 and comes over a peak of the eclipse rate. When it goes over
this peak, the eclipse rates decrease slowly, and it is 20% in August 2009,
and it is all sunshine (the period when the sun continues being) in
February 2010.

Because we follow for about 8 months, as for all sunshine, it seems that
we can apply the analog system relay consecutively for this period.


Name: Mineo Wakita / JE9PEL, JAMSAT member
Mail: ei7m-wkt@asahi-net.or.jp
URL : http://www.ne.jp/asahi/hamradio/je9pel/
QTH : Yokohama Japan, GL:pm95tj
Date: Aug 10, 2007

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