ESA's BepiColombo, the dual spacecraft mission to Mercury, conducted in partnership with Japan, is one of the most challenging ever decided. It is due to be launched by Ariane in 2014. The programme has just passed a significant milestone with the completion of the first crucial thermal tests at ESA's technical & research centre in the Netherlands. ESA's planetary missions can go from one extreme to another: whilst the Rosetta comet probe pursues its journey in the cold depths of deep space, its solar panels having to retain the weak rays of our distant Sun, BepiColombo will be braving the infernal heat around the innermost planet.