ESA’s comet rendezvous mission has been selected as a 'Cornerstone' mission of ESA’s long-term science programme 'Horizon 2000'.

The mission's goal is a rendezvous with a comet. The spacecraft will map the comet’s surface in fine detail and deploy a package of instruments (the Rosetta lander) to study some of the most primitive, unprocessed material in the solar system. The mission will provide clues to the physical and chemical processes that marked the systems beginning 4600 million years ago.

Credits: ESA-Service Optique CSG

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.

Credits: ESA, image by AOES Medialab

Rosetta’s 11-year expedition began in March 2004, with an Ariane 5 launch from Kourou in French Guiana, and the spacecraft was then sent towards the outer Solar System. The long journey includes three gravity assists at Earth (2004, 2007, 2009), one at Mars (2007), and two asteroid encounters: (2867) Steins (2008) and (21) Lutetia (2010).

After the third Earth-gravity assist and a large deep-space manoeuvre, the spacecraft will go into hibernation (July 2011 – January 2014). During this period, Rosetta will record its maximum distances from the Sun (about 800 million kilometres) and Earth (about 1 thousand million kilometres). The spacecraft will be reactivated prior to the comet-rendezvous manoeuvre, during which the thrusters will fire for several hours to slow the relative drift rate between the spacecraft and comet to about 25 m/s.

Credits: ESA, image by AOES Medialab

Immediately after touchdown in November 2014, a harpoon will be fired to anchor the lander and prevent it from escaping the comet’s extremely weak gravity. The minimum targeted mission time for Philae is one week, but surface operations may continue for many months. The measurements from the Rosetta orbiter will last from August 2014 to the end of 2015.

Credits: ESA / AOES Medialab