Designed to orbit the Earth at an altitude of just 250 km, GOCE (Gravity Field and Steady-State Ocean Circulation Explorer) is dedicated to measuring the Earth's gravity field for modelling the geoid with unprecedented accuracy and spatial resolution. The side of GOCE that faces the Sun is equipped with solar panels whilst the cold side, which remains facing away from the Sun, is used in part as a radiator to dissipate heat into space.