November 17, 2015 Landsat 8 TIRS Anomaly Update

The Landsat 8 Thermal Infrared Sensor (TIRS) Scene Select Mirror (SSM) encoder electronics anomaly investigation continues. In the meantime, Landsat 8 Level-1 products will continue to be made available consisting of valid data for the OLI solar reflective bands but with zero-fill data for the TIRS bands until corrections can be released in early 2016. 

The Landsat 8 flight operations team (FOT) continues to monitor current levels within the thermal infrared sensor (TIRS) Scene Select Mirror (SSM) encoder electronics.  The FOT and Calibration Validation team are continuing to investigate the current anomaly and analyze instrument telemetry data in order to accurately measure the position of the SSM and to develop the necessary parameters for the processing TIRS data under an alternative operations concept.  TIRS data will continue to be routinely collected but will not be processed to Level-1 products until the geometric model parameters are finalized and the algorithms and code in the Landsat Product Generation System (LPGS) have been updated, tested, and verified.  These activities are expected to be completed no sooner than February 2016. At which time all products will be reprocessed to provide valid TIRS data. Following the implementation of an alternate TIRS processing capability, the zero-fill Landsat 8 scenes will be reprocessed and made available from the USGS archive.  Mission operations will continually assess potential opportunities for return to normal operations on the B-side encoder electronics. However, at this time, the probability of return to normal operations is unknown.