On-Orbit Thermal Performance of the SMOS payload-MIRAS

The Soil Moisture and Ocean Salinity (SMOS) satellite was launched from Plesetzk cosmodrome, in northern Russia, onboard a Rockot launcher on November 2 2009 carrying an interferometric radiometer called MIRAS (Microwave Imaging Radiometer using Aperture Synthesis). During the Launch and Early Orbit Phase (LEOP) and following the satellite separation from the launcher, the sequence of events included the solar arrays automatic deployment followed by the so-called barbecue mode with the satellite pointing to the Sun, the MIRAS three arms deployment, several satellite attitude changes and finally, the MIRAS full switch-ON. This paper provides a brief overview of the MIRAS thermal design and environmental testing and reviews its on-orbit thermal performance until now, first examining the most critical activities performed during LEOP and then assessing the thermal behavior during nominal operations. The available telemetry acquired by the platform and by the payload itself and, in particular, the actual payload temperature and the heater power consumption have been compared with the predictions derived from a detailed correlated thermal mathematical model.