In orbit validation of the Sentinel 5 Precursor TROPOMI earth observation instrument thermal control system

The Tropospheric Monitoring Instrument (TROPOMI) on ESAs Sentinel 5 Precursor spacecraft was launched on October 13th 2017. The TROPOMI instrument has been developed under instrument prime responsibility of AIRBUS Defence and Space Netherlands BV and is jointly funded by ESA and the Kingdom of the Netherlands with NL Programme management by the Netherlands Space Office (NSO). The mission of this instrument is to perform observations on air quality and on sources and sinks of air quality and climate related gases and aerosols. TROPOMI is a passive Solar backscatter imaging spectrometer sensitive in several spectral bands from ultraviolet (UV) to Short Wave Infrared (SWIR), allowing deep penetration into the atmosphere, observing scattered radiation close to the Earth’s surface. The instrument’s spatial resolution of 7 x 7 km2 results in a high fraction of cloud-free observations. The wide swath range allows daily Earth coverage. The four 2D detectors in the instrument (SWIR, NIR, UVIS, UV) are cooled down to temperature levels varying from 140 K to 210 K to reduce the dark current output

This paper focusses on the in-orbit thermal observations, the correlation with the thermal predictions and the potential fine-tuning of the parameters in the active thermal control systems. Based on the correlated thermal model and in orbit observations, the extreme lifetime excursions have been re-assessed. The outcome of the in orbit validation will be used to define the final settings for the thermal control system in order to ensure full performance during the entire life time.