Thermal modeling and experimental verification of the HEPS radiation monitor heat dissipation management

A concept of the small radiation monitor was developed in the bridge phase of the ESA planned VIGIL mission. RM was required to dissipate its heat to the outer space while the thermal link with the S/C was designed to be weak. Radiation monitor had an aluminum housing consisting of an upper and a lower parts, as well as a rear wall which served as a radiator. Within the housing, detector telescopes and PCBs were mounted. Heat from both solar radiance and internal generation was dissipated solely through radiators while the unit was isolated and protected with MLI. Technical challenges of heat dissipation were addressed and solved using modelling based on the ANSYS software. Fully representative thermal model was constructed and tested using dedicated experimental setup in a cryogenic chamber. Measurements obtained for various operation modes of the instrument proved the thermal model concept and validated calculation results.