During the entry of the EXOMARS Entry & Descent Module (EDM) demonstrator in the Martian atmosphere, the module is surrounded by a high enthalpy flow consisting of excited CO_² molecules.

The German Aerospace Center (DLR) has been developing a Combined Aerothermal and Radiometer Sensor Package (COMARS+) for the ESA EXOMARS EDM mission in 2016. COMARS+ consists of three so-called COMARS sensors, one broadband radiometer and one electronic box for analogue signal processing.

COMARS sensors measure the pressure, convective heat flux rate and radiative heat flux rate simultaneously. Further fiber optic temperature sensors are used for health-monitoring of the sensor unit. Each COMARS sensor contains two narrow band radiometers. This sensor, which is called ICOTOM, includes fluoride fiber and measures the CO_²radiation at two distinct wavelengths (2.9 µm and 4.5 µm).

ICOTOM has been developed and calibrated by Le Verre Fluoré, and has been integrated into the COMARS+ housing by DLR.