European space satellite GOCE to map Earth's gravitational field

Posted by Samantha Rose Hunt

Europe - A new European Space Agency satellite will be launching this year, possibly as soon as February. Its job will be to map out the planet's gravitational field in extreme detail. The Gravity Field and steady-state Ocean Circulation Explorer (GOCE) will be launched for the purpose of gathering data to be used in oceanography, climate change, and solid Earth physics. GOCE is the first Core Earth Explorer satellite to be developed as part of ESA's Living Planet Programme.







Details for this device provided from the article link below:

"The GOCE gradiometer consists of three pairs of identical ultra-sensitive accelerometers, mounted on three mutually orthogonal 'arms' (see upper part of the image). It also contains other elements related to the gradiometer control and read-out electronics, to the structure and to the thermal control elements. The three arms are mounted orthogonal to one another: one aligned with the satellite’s trajectory, one pointing towards the centre of the Earth, and the third is perpendicular to the other two.



The principle of operation of each ultra-sensitive accelerometer relies on measuring the electric field required to maintain a 'proof mass' at the centre of a specially engineered 'cage'. Servo-controlled electrostatic suspension provides control of the 'proof mass' in terms of linear and rotational motion. The difference between accelerations measured by each pair of accelerometers (which are 50 cm apart) is the basis for the gravity gradients. Credits: ESA - AOES Medialab."






Satellite's mission



The satellite will be capable of measuring the Earth's gravity from location to location as it circles the globe. This effort will provide a complete, uniform global picture with detail and accuracy never before possible. This new sampling will give scientists and researchers more insight into the circulation of the ocean, how it affects climate change and even hints as to the interior structures of the Earth.



The basic theory is this: The strength of Earth's gravity varies by tiny amounts at different locations around the globe based on its makeup. As the GOCE orbits the Earth at 155 miles above the surface, over its 20 month mission it will compile a full 3-D map of every point in orbit.



Scientists report they'll even be able to use the satellite's compiled data to accurately measure heights for various features around the globe - such as Mount Everest and Mount St. Helens, both of which currently have varying height estimates which span a fairly wide range.



If successful, the GOCE will deliver an improved accuracy of the Earth, forever changing the way it is perceived by man and science.



See an August, 2006 GOCE article on ESA's website, along with the other Core Earth Explorer satellites, including ADM-Aeolus scheduled for launch in 2010 (to measure wind using lidar) and EarthCARE due for launch in 2013, along with nine additional satellites.