An artist’s impression of Rosetta approaching the nucleus of Comet 67P/Churyumov-Gerasimenko.

Rosetta’s 11-year expedition began in March 2004, with an Ariane 5 launch from Kourou in French Guiana. Using three Earth-gravity assists (2004, 2007, 2009) and one at Mars (2007), the spacecraft was propelled towards the outer Solar System. It has encountered two asteroids, (2867)Steins in 2008 and (21)Lutetia in 2010, and is now cruising to its final destination.

Rosetta will reach the comet in 2014, and will be the first mission ever to orbit a comet’s nucleus and to deliver a lander, called Philae, on its surface.