Landsat 9 TIRS-2 Spectral Response Test: Updates & Perspective

The Thermal Infrared Sensor 2 (TIRS-2) pre-launch spectral characterization at telescope and detector subsystem level provided a strong indication that the spectral response requirements will be met. Confidence in the validity of these results was strengthened through comparison to component-level measurements. This work reviews the modifications to the test setup to reduce spectral response uncertainties further in preparation for instrument-level testing. We developed a methodology to improve alignment repeatability of the upgraded system. Preliminary indications show that the spectral response will contribute a relatively small amount to the overall TIRS-2 radiometric uncertainty budget, which is expected to meet its radiometric requirements. Through spectral response testing, as part of a comprehensive pre-launch test program, TIRS-2 is expected to achieve the performance necessary for a variety of environmental applications.