To be able to measure the strength of Earth’s gravity, the GOCE satellite flew in an extraordinarily low orbit about 255 km high – about 500 km lower than most Earth observation satellites. At the end of 2012, low fuel consumption allowed operators to extend the mission’s life and start to lower the satellite a further 31 km for even more accurate measurements. This was at the very limit of its capability but maximised the return for science. Although GOCE’s mission ended in October 2013, the data from this low orbit have improved our understanding of Earth’s interior, including the location of oil and gas.