Gaia is an ambitious mission to chart a three-dimensional map of our Galaxy, the Milky Way, in the process revealing the composition, formation and evolution of the Galaxy. Gaia will provide unprecedented positional and radial velocity measurements with the accuracies needed to produce a stereoscopic and kinematic census of about one billion stars in our Galaxy and throughout the Local Group. This amounts to about 1 per cent of the Galactic stellar population.
This rendering shows Gaia in its mission phase, with its sun shade full deployed. The crescent of the earth is illuminated by the sun, and the spacecraft's camera is pointed outside the solar system.