Gravity satellite prepares for launch

A new satellite that will measure the Earth's global gravity field considerably more accurately than is currently achievable by other satellite and terrestrial means is being prepared for launch in Russia at the end of May.

Part of the European Space Agency's Living Planet Programme, the GOCE mission (Gravity Field and Steady-State Ocean Circulation Explorer) will help UK researchers to locate gravity anomalies around the world and link them to the deep Earth processes that cause earthquakes and volcanic activity.

'GOCE will skim the edge of our atmosphere, orbiting at a low altitude where the satellite will be sensitive to the strongest possible gravity field signal. For the first time a gradiometer will be used in space so the measurements will be far more accurate,' said Prof Philip Moore from Newcastle University, who specialises in gravity research.

The gradiometer is based on six ultra-sensitive accelerometers and is able to achieve very accurate measurements. GOCE will gather the data at an altitude of around 270km above the Earth and will capture spatial scale measurements at around 100km. The best scale measurement that can be obtained from existing satellites is around 600km.

The mission has a limited life-span of around 20 months, and once the satellites' fuel has been used up, it will be allowed to fall to Earth where it will burn up in the atmosphere.

'This is a very challenging mission as GOCE will be constantly battling against the effects of air-drag to obtain these measurements. However, the benefits to researchers will be vast. It will provide us with a better understanding of ocean circulation and volcanism and even the processes that lead to accumulation of stresses and the triggering of earthquakes,' Prof Moore added.