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Calibration plan for the Thermal Infrared Sensor on the Landsat Data Continuity Mission

The Landsat Data Continuity Mission consists of a two-sensor platform with the Operational Land Imager and Thermal Infrared Sensor (TIRS). Much of the success of the Landsat program is the emphasis placed on knowledge of the calibration of the sensors relying on a combination of laboratory, onboard, and vicarious calibration methods. Rigorous attention to NIST-traceability of the radiometric calibration, knowledge of out-of-band spectral response, and characterizing and minimizing stray light should provide sensors that meet the quality of Landsat heritage. Described here are the methods and facilities planned for the calibration of TIRS which is a pushbroom sensor with two spectral bands (10.8 and 12 micrometer) and the spatial resolution 100 m with 185-km swath width. Testing takes place in a vacuum test chamber at NASA GSFC using a recently-developed calibration system based on a 16-aperture black body source to simulate spatial and radiometric sources. A two-axis steering mirror moves the source across the TIRS field while filling the aperture. A flood source fills the full field without requiring movement of beam providing a means to evaluate detector-to-detector response effects. Spectral response of the sensor will be determined using a monochromator source coupled to the calibration system. Knowledge of the source output will be through NIST-traceable thermometers integrated to the blackbody. The description of the calibration system, calibration methodology, and the error budget for the calibration system shows that the required 2% radiometric accuracy for scene temperatures between 260 and 330 K is well within the capabilities of the system.