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[amsat-bb:74768] AO-40 Update, 2004-01-29
Initial attempts to turn on the K-tx with short machine code commands did
not result in a detectable signal, but this will be repeated. Several
additional cycles with the S2 have been repeated as well without
result. These attempts always terminate with transmitter off commands, and
simple commands to try to switch the battery to the aux. mode.
Our hypothesis remains that we have a battery failure clamping the voltage
low. We're looking at the spacecraft physical and electrical layout and
even the "flaky" heatpipe reading to see if we can come up with a more
detailed failure point explanation.
If our theory is correct, the remaining cells of the main battery are
taking quite a beating as the BCR's try unsuccessfully to bring them up to
the set point voltage of about 28 volts. We expect that more than 6 amps
are flowing through the remaining cells in the main battery and this
current will increase by about 30% as the solar angles improve. We only
need for one of these cells to lose enough electrolyte to "open" and we
could be back in business. I'll repeat my comment from before that time is
an unknown here and days or weeks without result do not mean ultimate failure.
I will be out of town for two days on an unavoidable business trip, but
will update the bulletin board when I return on Sunday. The command team
will continue to try to regain the S2 and K Tx's and report any successes here.
--W4SM for the AO-40 Command Team
--
________________________________________________________________________
Stacey E. Mills, W4SM WWW: http://www.keplerian.com
Charlottesville, VA PGP key: http://www.keplerian.com/key
________________________________________________________________________
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