On 11 November 2013, ESA’s GOCE satellite reentered Earth’s atmosphere on a descending orbit while most of it disintegrated, as expected, within the high atmosphere. The Gravity field and steady-state Ocean Circulation Explorer – GOCE – was launched in March 2009 to map with precision variations in Earth’s gravity. A proof of the success of this mission is the most accurate shape of the ‘geoid’ – a hypothetical global ocean at rest – ever produced, which is being used to understand ocean circulation, sea level, ice dynamics and Earth’s interior.
Furthermore, GOCE has also provided new insight into air density and wind speeds in the upper atmosphere thanks to its accelerometer measurements and its innovative ion engine, which was responsible for keeping the satellite at an incredibly low orbit of under 260 km.
Once the satellite ran out of fuel on 21 October it gradually started to descend and its mission came to a natural end. After three weeks descending GOCE penetrated the atmosphere where most of the 1100 kg satellite disintegrated, leaving an estimated 25% to reach safely Earth’s surface. “In the 56 years of spaceflight, some 15 000 tonnes of man-made space objects have reentered the atmosphere without causing a single human injury to date” said Heiner Klinkrad, Head of ESA’s Space Debris Office.