The European Space Agency (ESA) on Thursday (December 19) successfully launched its billion-star surveyor Gaia at 9:12:19 GMT from Europe's spaceport in Kourou, French Guiana.
Fuelling of the launch vehicle, a Soyuz ST-B rocket, started about four hours before.
The 53 metre-high mobile gantry surrounding the vehicle was removed before the final countdown began.
Gaia's mission is to conduct the biggest cosmic census yet, charting the positions, motions and characteristics of a billion stars to create the most precise 3D map of the Milky Way.
Gaia will be conducting its mission from 'L2', a gravitationally stable point in space some 1.5 million kilometres 'behind' Earth as seen from the Sun.
Gaia is expected to arrive in its orbit around L2 in about three weeks' time.
Presented by Adam Justice