ESA GOCE mission

http://m.esa.int/Our_Activities/Observing_the_Earth/GOCE/Taking_gravity_from_strength_to_strength

Citando:
"Ten years ago, ESA launched one of its most innovative satellites. GOCE spent four years measuring a fundamental force of nature: gravity. This extraordinary mission not only yielded new insights into our gravity field, but led to some amazing discoveries about our planet, from deep below the surface to high up in the atmosphere and beyond. And, this remarkable mission continues to realise new science today.

Because of factors such as the planet’s rotation, the position of mountains and ocean trenches and different densities in materials in Earth’s interior, the force of gravity at Earth’s surface varies from place to place."