The ESA-JAXA BepiColombo mission to Mercury must withstand extremely harsh conditions while in orbit around the innermost planet of our Solar System: temperatures in excess of 450 C, high ultraviolet and electron and proton fluxes. ESA’s Materials and Electrical Components Laboratory was called in by the mission team to test the performance of candidate materials and components throughout the spacecraft – including the high gain antenna used to return the mission’s scientific findings. Heat-resistant ceramic coatings for the antenna were assessed in simulated conditions.