The launch of a spacecraft, using an Ariane-5 rocket.

At 0736 GMT on Tuesday the 2nd March 2004, the European Space Agency's Rosetta Mission was launched from Kourou in French Guiana.

From here the chase is on to catch comet 67 P/Churyumov-Gerasimenko. The spectacular journey will take 10 years, before instruments on board the Rosetta Orbiter are able to map the comet surface at close range. A safe landing site will be chosen, and the Rosetta Lander will be ejected to make the first ever soft landing on a comet surface. A suite of instruments on board the Lander will then analyse in great detail the comet surface and sub-surface.

This is a unique chance to gain an intimate insight into the nucleus of a comet - a time capsule, preserved in space, thought to contain pristine samples of the matter from which our Solar System formed millions of years ago.

Scientists at the Open University in Milton Keynes are particularly interested in the water frozen on the comet: could this water be linked to the evolution of the first life forms on Earth? To answer this question, they have built the Ptolemy instrument for the Rosetta Lander, in conjunction with the Rutherford Appleton Laboratory and funded by PPARC. The Ptolemy instrument is described on this web site.