Satellites in airless space must endure high and low temperatures simultaneously, as some parts are exposed to sunlight and others remain in shadow. In advance of launch satellites are exposed to vacuum for prolonged periods, to ensure they can withstand extreme space conditions and maintain optimal internal temperature levels. Alessandro Cozzani, ESA’s Head of Engineering Services Section at the ESTEC Test Centre explains the advanced photogrammetry and thermal cameras which gather data during these challenging ‘thermal vacuum’ tests.