Bepi Colombo is an ESA mission targeted to the exploration of Mercury with two spacecraft, a Mercury Polar Orbiter (MPO) provided by Europe and a Mercury Magnetospheric Orbiter (MMO) provided by Japan. The Mission is lead by Astrium Friedrichshafen, with Thales Alenia space Torino responsible for the MPO thermal design.
The MPO is a 3-axis stabilized scientific spacecraft in Mercury polar eccentric orbit, with altitude from 400 to 1500 km, with one face planet oriented and pointing Nadir, and housing the apertures of the observation P/L.
Studies for this mission were initiated in the late 90ies, and pointed out that one of the main design drivers for the MPO was the thermal environment in orbit, due to the combination of high solar constant (up to 10 solar constants on Earth), infrared and albedo from the planet (maximum IR up to about 4 terrestrial solar constants, albedo up to about 1).
The thermal constraint drove the configuration of the spacecraft, in particular the position and the design of the radiators, that were the subject of two separate Technology Demonstrator Activities (TDA) awarded by ESA to Astrium and Thales Alenia Space, in the period 2004 to 2006, aimed to design and verify by test the radiator.
This paper describes the Thales design concept, the test setup to simulate the influence of the hot Mercury surface, the tests, their correlation and the extrapolation of performances to flight conditions.