Landsat 8 and its two Earth imaging sensors, the Operational Land Imager (OLI) and Thermal Infrared Sensor (TIRS) have been operating on-orbit for 2 ½ years. Landsat 8 has been acquiring substantially more images than initially planned, typically around 700 scenes per day versus a 400 scenes per day requirement, acquiring nearly all land scenes. Both the TIRS and OLI instruments are exceeding their SNR requirements by at least a factor of 2 and are very stable, degrading by at most 1% in responsivity over the mission to date. Both instruments have 100% operable detectors covering their cross track field of view using the redundant detectors as necessary. The geometric performance is excellent, meeting or exceeding all performance requirements. One anomaly occurred with the TIRS Scene Select Mirror (SSM) encoder that affected its operation, though by switching to the side B electronics, this was fully recovered. The one challenge is with the TIRS stray light, which affects the flat fielding and absolute calibration of the TIRS data. The error introduced is smaller in TIRS band 10. Band 11 should not currently be used in science applications.
