Computing New Satellite to Measure Gravity Lifts Off The spacecraft will measure the earth’s gravitational field with new accuracy. by Brittany Sauser March 17, 2009 Sponsored by A European Space Agency satellite called GOCE (Gravity field and steady-state Ocean Circulation Explorer) will measure the earth’s gravitational field with unprecedented accuracy. Here GOCE is seen undergoing tests at the Plesetsk Cosmodrome in Northern Russia in August 2008. The satellite was originally scheduled to launch in late August, but the launch was postponed until March 2009. Researchers maneuver the satellite inside a clean room at the Plesetsk Cosmodrome on March 16. The satellite underwent checks in the clean room before being mounted to the rocket’s upper stage. After being encapsulated in a protective “fairing,” final checks are performed. The launch tower at Plesetsk used for the launch of GOCE. ESA’s Danilo Muzi, GOCE project manager (right), and Andrea Allasio, GOCE project manager for Thales Alenia Space (left), during a launch rehearsal at Plesetsk on March 13. GOCE blasted off at 10:21 A.M. (EST), March 17, 2009. Over 24 months, GOCE will map global variations in the earth’s gravitation field with better accuracy and higher spatial resolution than ever before. These measurements should help scientists monitor ocean currents and circulation and sea-level ice-mass changes, and help them model climate change. To measure the earth’s gravitational field, GOCE carries a gradiometer containing six accelerometers. These sensors are positioned in pairs along the three axes of the gradiometer. The data that they collect will be used to create a map of the earth’s gravitational field. GOCE will fly at an altitude of about 260 kilometers and use ion engines to compensate for the deceleration caused by atmospheric drag.