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December 17, 2014 - Landsat 8 Processing Resumed

Landsat 8's Thermal Infrared Sensor (TIRS) returned to its normal operating mode December 13, 2014 after completing a TIRS test activity that began December 9, 2014.

This activity was done to evaluate operating the TIRS in a mode that could potentially extend the life of the instrument. Since this mode prevented the acquisition of calibration collects, the radiometric accuracy was slightly reduced by less than 0.03 W/(m2 sr mm) or 0.2 K when viewing a 300 K target. This mode also allowed the Scene Select Mechanism (SSM) to drift away from its nominal nadir position, causing the TIRS image frame to move slightly relative to the OLI image frame. Calibration parameters were adjusted to allow this shift to occur without causing any measurable geometric alignment changes.