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.

An amazing 10-year interplanetary trek
 

 
An artist’s impression of Rosetta waking from deep-space hibernation to rendezvous with Comet 67P/Churyumov-Gerasimenko in 2014.

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.


 
An image of Comet 67P/Churyumov-Gerasimenko. Our Solar System is home to one star, nine planets and dozens of planetary satellites. It also contains millions of asteroids and comets – the left-over debris from the cosmic construction site that created the planets and their moons.

Rosetta’s task is to study these primitive building blocks at close quarters so that scientists may gain new insights into the events that took place 4600 million years ago, during the birth of Earth and its planetary neighbours.

Studying a comet on the spot
 

 
Artist’s view of ESA's Rosetta spacecraft design. Visible on the front side of the spacecraft is the tiny Philae lander. The spacecraft is covered with dark thermal insulation in order to keep its warmth while venturing into the coldness of the outer Solar System, beyond Mars’s orbit.

Selected in November 1993 as a cornerstone mission of ESA's long-term science programme, the Rosetta probe was launched by an Ariane 5 on 2 March 2004, on an 11-year journey to the Comet 67P/Churyumov-Gerasimenko.

Built by EADS Astrium, the Rosetta probe consists of a 3065-kg spacecraft (1578 kg dry mass) designed to enter orbit around the comet's nucleus in August 2014 after a series of gravity assist manoeuvres to gain enough orbital energy, with three swing-bys at Earth (March 2005, November 2007 and November 2009) and one at Mars (February 2007). En route to the comet, the probe will fly-by the asteroids (2867) Steins (September 2008) and (21) Lutetia (July 2010).

The spacecraft carries 11 science instruments to probe the comet's nucleus and map its surface in fine detail. It will also land a package of instruments (the Philae 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 at work during the formation of planets, beginning 4600 million years ago.

Building Rosetta
 

 
The picture shows the Rosetta orbiter in preparation for thermal testing in the Large Space Simulator at ESA's ESTEC facility, The Netherlands. The spacecraft is covered in thermal blanket insulation, and the small white rectangular features on the near side are the radiating louvres.



Release date: 12 May 2004