Modelling the thermal emission from airless planetary surfaces and sub-surfaces

International audienceBoth the Cassini (NASA/ESA/ASI) and Rosetta (ESA) spacecrafts have onboard a radiometer operating at relatively large wavelengths, respectively in the microwave and sub-millimetric domains. At such wavelengths, these instruments sense the thermal emission not only from the surface but also from a section of the sub-surface of the targeted bodies. As a consequence, the interpretation of radiometric data collected over the airless icy satellites of Saturn by Cassini and over the comet 67P/Churyumov -Gerasimenko by the Rosetta orbiter requires a good knowledge of the temperature profile below the surface, down to several meters. In this paper we describe the thermal model we developed in order to interpret Cassini current and Rosetta future radiometric measurements