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Uppdatering 29 jan

Senaste nytt angende Oscar 40:

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

Klla: W4SM

By SM0TGU

Webmaster and member of the AMSAT-SM steering group.

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