Landsat 5 has orbited Earth over 150,000 times since it was launched in 1984, making it the longest-operating Earth observation satellite of its kind. During this time, two data collection instruments onboard Landsat 5 – the thematic mapper (TM) and the multi-spectral scanner (MSS) – have transmitted over five million images of land conditions to US and international ground stations.
In November 2011, an electronic malfunction in the TM transmitter forced a suspension of routine imaging. Now, after months of trying without success to restore daily TM image transmissions, USGS flight engineers will attempt only a few additional image acquisitions over specific sensor-calibration sites as the TM transmitter nears complete failure.
On a positive note, the MSS instrument onboard Landsat 5 was recently powered back on in a test mode after more than a decade of silence.
"The resurrection of the MSS a decade after it was last powered up and 25 years beyond its nominal lifespan is welcome news indeed," said USGS Director Marcia McNutt. "While not a complete replacement for the loss of the Thematic Mapper, it does provide some insurance for ensuring Landsat data continuity should Landsat 7 fail prior to Landsat 8 achieving orbit next year."