Thermal Analysis of the Solar Orbiter PHI Electronics Unit

This paper presents the thermal design of the electronics unit of the instrument Polarimetric Helioseismic Imager, onboard the European Space Agency mission Solar Orbiter. The thermal design procedure, along with the problems encountered during this design phase, and the solutions found to fix them are described, proving in this way the thermal feasibility and robustness of the unit. Its final thermal behaviour, obtained from thermal analyses correlated with data from thermal tests performed in a vacuum environment, is presented.