As it is only some 58 million kilometres from the Sun, Mercury presents a special challenge to visiting spacecraft. During the day, the planet’s surface exceeds temperatures of 350 deg. Celsius or more, which is hot enough to melt some metals. As a result, spacecraft in Mercury´s orbit not only have to cope with the immense heat of the Sun, but also with the infrared radiation emitted by the planet.
In consequence, the BepiColombo team has covered every external surface of ESA’s MPO, except for the single radiator side, with high-temperature, multi-layered insulation. The material, made up of 50 layers of ceramics and aluminium, was especially designed for the BepiColombo mission. The antennas are made of heat-resistant titanium, covered by a newly developed coating.
As the MPO’s mission is to investigate Mercury’s surface, one side will always be facing the planet, so that the instruments can monitor the surface at all times, while the radiator faces away from the planet into deep space to dissipate heat.