AMSAT-NA VP Operations Drew Glasbrenner KO4MA reports on Friday’s IHU crash on the Amateur Radio satellite AO-51. Sometime between 1815 and 1945Z November 25, AO-51′s IHU crashed. This happened after a few days of intermittent and unpredictable operation.

Mark N8MH and I reset the satellite and started the repeater back up around ~2030Z, and lowered the output power to about 300 milliwatts. Battery voltage was low, around 4.9v, with cell 1 less than 1 volt. This is very troublesome, as the impending third cell failure will likely end our continuing operations, particularly if it fails shorted as the others have. We’ve also observed the transmitters cutting off around 4.7 to 4.6 volts prior to the last reset, in eclipse.

We’ll do what we can, but her days are short. Let me ask once again for more reports, especially from the US operators, to the Live Satellite Status webpage. The command stations monitor this for changes in the operation of AO-51, and while worldwide participation is good, few US operators post to it.

Update Nov 27, 2011:

AO-51 still off-air. Satellite is not responding to commands, we suspect that the 3rd cell has failed short, therefor insufficient voltage for the transmitter.