NOAA-15 STX2 (HRPT TX) experienced an abrupt decrease in output power.
The output power dropped 4.71 W (from 5.96 W to 1.25W) and the orbital maximum temperature decreased 3°C (from 30°C to 26°C). STX2’s output power has been stable since the drop and the CDAS have not reported any problems receiving HRPT data from STX2.
Engineering is currently investigating switching the HRPT data stream to either STX1 or STX3, which have not been used since LEOP (Launch and Early Orbit Phase) due to interference between the STXs and the AMSU-B instrument. STX4 is the only other STX being used on N15 and is designated for DTR playbacks.