Dr. Gerhard Schwehm, lead scientist for the Rosetta project, explains that, "With this mission we will be breaking new ground - this will be the first protracted cometary encounter."

The trip to the meeting place in space will certainly be a long one, located as it is some 4.5 astronomical units from the Sun, which translates into something like 675 million kilometres. Rosetta will be on the road for ten years, during which time it will clock up in excess of five billion kilometres.

Launch in February 2004

Rosetta will be waved off on 26 February when it lifts off from the space centre in Kourou, French Guiana, aboard an Ariane 5 launcher. Shortly after the spacecraft's release, its solar panels will be deployed and turned towards the Sun to build up the necessary power reserves. Its various systems and experiments will be gradually brought into operation and tested. Just three months into the mission the first active phase will be over, followed by final testing of the experiments in October 2004. Rosetta will then spend the following years flying a lonely path to the comet, passing by the Earth, Mars, the Earth and the Earth again.

There is no alternative to this detour, for even Ariane 5, the most powerful launcher on the market today, lacks the power to hurl the probe on a direct route to the comet. To get the required momentum, it will rely on swing-by manuvres, using the gravitation pull of Mars (in 2007) and the Earth (three times, in 2005, 2007 and 2008) to pick up speed.

Asteroids for company

A change is as good as a rest, and a meeting with at least one asteroid should help break the monotony for Rosetta. The spacecraft will
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Contact: Franco Bonacina
franco.bonacina@esa.int
33-1-53-69-7155
European Space Agency
3-Feb-2004