The European Space Agency’s Gravity field and steady-state Ocean Circulation Explorer (GOCE) satellite was launched on 17 March 2009. Its mission is to orbit the Earth while performing very high resolution measurements of Earth’s gravity field. GOCE will, over 24 months in orbit, provide a map of Earth’s “geoid” (that is, its idealised shape – smooth but irregular – based on the varying strength of gravity accross the globe) with an accuracy of just 1-2 cm in altitude and 100 km accross. The GOCE map will provide an advanced baseline from which scientists can monitor sea-level changes and ice-sheet evolution with much more accuracy than ever before.