High-definition map of the world's gravity

The Gravity Field and Steady-State Ocean Circulation Explorer (Goce) is at the front of this armada of scientific and environmental monitoring spacecraft.

Launched in 2009, the sleek satellite flies pole to pole at an altitude of just 254.9km - the lowest orbit of any research satellite in operation today.

The spacecraft carries three pairs of precision-built platinum blocks inside its gradiometer instrument that sense accelerations which are as small as 1 part in 10,000,000,000,000 of the gravity experienced on Earth.

This has allowed it to map the almost imperceptible differences in the pull exerted by the mass of the planet from one place to the next - from the great mountain ranges to the deepest ocean trenches.