The satellite mapped variations in the Earth's gravitational field, allowing it to measure ocean currents, investigate the mantle, even probe inside hazardous volcanic regions. There was a real risk it would find a secret Bond villain. Which is the most reasonable explanation for how it got hit by an earthquake in space. The 2011 Tohoku earthquake turned tectonic plates into the world's biggest sub(terranean)woofer. This vibrated the entire atmosphere so hard it even affected GPS signals by shaking the ionosphere. But the GOCE was flying low enough to feel the acoustic wave. This wasn't a detection of the ground shaking: Its accelerometers and orbital correction thrusters felt the shaking from 260 kilometers straight up.
Planetary Visions via ESA
The thing about an earthquake is, you're meant to be on Earth for them to work.
The GOCE was without question the most gorgeous powered satellite ever built.
ESA-Anneke Le Floc'h
"It's perfectly ready; we just want to look at it for a bit longer."
A xenon ion engine for thrust, magnetotorquers pushing against the Earth's magnetic field for attitude control, fins for flying through the thermosphere; it was a shiny sliver of The Future Is Now. And don't be worried by my use of the past tense. GOCE operated for almost triple its intended lifespan before diving into the atmosphere to rejoin the planet it had studied for so long, which it understood more deeply than anyone ever had before.
Others are distracted by the blue pools on the surface, but GOCE saw what it was like deep down.