Radiometric and angular calibration tests for the MEDA-TIRS radiometer onboard NASA’s Mars 2020 mission

This article describes a comprehensive testing method for the radiometric and angular calibration of the Thermal InfraRed Sensor (TIRS) onboard NASA’s Mars 2020 mission. First, details of the TIRS optomechanical design, construction aspects of the IR detectors, and an update of the mathematical model used for the calculation of sensor internal IR fluxes are provided. Then, a set of sequential calibration tests to identify the radiometer model parameters are defined. The test setups are described, highlighting their limitations and restrictions based on differences between simulated and actual Martian environmental conditions. Finally, the uncertainty sources and potential systematic errors associated with the calibration tests are quantified and compared with the radiometer scientific requirements established by the Mars 2020 science team.