Harp Technologies has contributed to European Space Agency’s (ESA) Soil Moisture and Ocean Salinity (SMOS) mission by acting as External Support laboratory for SMOS Level 1 data calibration. In spring 2020, the SMOS team has initiated the 3rd mission data reprocessing campaign, during which all data products from the whole mission (10 years of data since 2009) are reproduced with the latest data processing improvements. For this reprocessing, Harp Technologies has delivered a radiometer response model that enhances the data quality especially under thermally challenging periods that the satellite confronts at orbit during the Northern winter periods. With the updated model the Sea Surface Salinity and Soil Moisture products of SMOS become more accurate and reliable.