AMSAT: AO-51 has stopped transmitting

The amateur satellite that goes by the name AO-51 has ceased transmission and is not responding to commands.  This satellite has been a mainstay for the last seven years for the amateur satellite community as one of the FM “easy” satellites (easy is relative). The last telemetry data indicated that the third of six batteries was approaching failure to short, and observations indicate the voltage from three cells is insufficient to power the UHF transmitters. The IHU may continue to be operative. Initial tests with the S band transmitter were also not positive, although more attempts are in order. We have tried leaving the satellite in an expected state where if voltages climb high enough, the 435.150 transmitter may possibly be heard.