The European Space Agency (ESA) satellite is able to achieve drag-free flight by employing an electric ion propulsion system that cuts through the remnants of Earth’s atmosphere.

ESA GOCE system manager Michael Fehringer said that initial data indicated that this drag compensation system works ten times better than what they had expected.

The system uses electrically-charged xenon to create a gentle thrust comprising tiny forces of one to 20 millinewtons, depending on the amount of drag the satellite experiences on orbit.

GOCE was launched into space on 17 March 2009 to collect data and measure the Earth’s gravity field with unprecedented accuracy.

For this, it needs to fly on a low orbit of 250km from the Earth, on the fringes of its atmosphere where the gravitational signal is strong, hence the requirement for the drag-free technique.

The electric propulsion system supports the spacecraft in maintaining ‘free fall’ for correct gravity measurements.

GOCE has already demonstrated the first gradiometer technology ever flown in space.

It was recently switched to drag-free mode as part of the commissioning and gradiometer calibration activities.