The Gravity field and steady-state Ocean Circulation Explorer (GOCE) spacecraft, developed and built by Thales Alenia Space for the European Space Agency (ESA), has completed its in-orbit commissioning and calibration phase, by successfully passing an in-flight test review last week. The satellite’s and the payload’s functionalities have been fully demonstrated and initial results from the first measurement campaign — initiated on September 15th and due to last through March 2010 — are already giving amazing results, even beyond the specifications in some frequency bands. Early measurements have been successfully correlated with existing models of the Earth gravity field and shown significantly higher level of spatial detail,

GOCE is the first satellite deployed on behalf of ESA’s Earth Explorer program. It was designed to provide the first 3D mapping of the Earth’s gravitational field, with an unprecedented level of accuracy. This unique spacecraft features an aerodynamic design to provide a low-altitude drag-free environment for a state-of-the-art and world-first gradiometer. Il will map the geoid with a resolution increased with unprecedented spatial resolution and accuracy which will open up new domains of geophysical research. Both the satellite and its gradiometer have been integrated by Thales Alenia Space in, respectively, its Turin and Cannes facilities.

As of October 29th, the satellite is in perfect shape and the drag caused by the upper atmosphere is below expectations, resulting in lower power consumption for drag compensation, with performance one order of magnitude beyond the specification. As a result, it is estimated that the measurement phases could be extended into the eclipse periods and the overall mission duration could be extended as well. Moreover, orbital positioning of the satellite has also reached an impressive level of accuracy that will translate directly into higher accuracy of the final measurements. GOCE’s 3D mapping of the geoid is expected to provide a global reference for oceanographic observation and the study of ice sheets, as well as for satellite tracking and the unification of the world’s altitude measurements. In addition, GOCE will map density variations in the higher levels of the Earth’s mantle.