Washington: ESA`s GOCE satellite that mapped variations in Earth`s gravity with unprecedented detail for four years, has run out of fuel and the end of mission has been declared.
Since March 2009, the Gravity field and steady-state Ocean Circulation Explorer - GOCE - has been orbiting Earth at the lowest altitude of any research satellite.
Its `gradiometer` - the sensitive instrument measuring gravity in 3D - was the first in space and has mapped variations in Earth`s gravity with unrivalled precision.
The result is a unique model of the `geoid`, which is essentially the shape of an ideal global ocean at rest and therefore critical for accurate measurements of ocean circulation and sea-level change.
GOCE has provided dynamic topography and circulation patterns of the oceans with unprecedented quality and resolution, improving our understanding of the dynamics of world oceans.
Scientists further exploited GOCE`s data to create the first global high-resolution map of the boundary between Earth`s crust and mantle - called the Moho.
Although the planned mission was completed in April 2011, the fuel consumption was much lower than anticipated because of the low solar activity, enabling ESA to extend GOCE`s life.
In August 2012, the control team began to lower the satellite`s orbit - from about 255 km to 224 km. Dubbed `GOCE`s second mission`, the lower orbit increased the accuracy and resolution of GOCE`s measurements, improving our view of smaller ocean features like eddy currents.