Landsat 9 Thermal Infrared Sensor 2 Spectral Response Test: Updates And Perspective

The Thermal Infrared Sensor 2 (TIRS-2) that will fly aboard Landsat 9 has undergone pre-launch spectral characterization to demonstrate that its spectral response requirements will be met with few waivers. The test was conducted both at the subsystem level and, after upgrading the test setup and improving the alignment methodology, at instrument-level as well. This work reviews these upgrades and alignment methodology that contributed to a reduction in spectral response uncertainties to a relatively small value relative to the overall TIRS-2 radiometric uncertainty requirements. The spectral response results show an increase in signal to noise ratio and reference detector stability from subsystem-level to instrument-level measurements. Spectral response testing is part of a comprehensive pre-launch test program that ensures TIRS-2 will achieve the performance necessary for a variety of environmental applications.