Rosetta is the third cornerstone mission of the ESA long term scientific programme Horizon 2000.
Rosetta is the first mission designed to both orbit and land on a comet. Rosetta comprises an orbiter that will follow the comet for many months as it heads towards the Sun, and a lander that will land on it. The spacecraft carries eleven scientific experiments to complete the most detailed study of a comet ever attempted.
Rosetta’s launch had been originally scheduled for January 2003 on board an Ariane-5 rocket. Rosetta’s target then was Comet Wirtanen, and the encounter had been planned to occur in 2011. However, following the failure of the Ariane Flight 157 in December 2002, with the loss of two spacecraft, ESA and Arianespace took the joint decision not to launch Rosetta during its January 2003 launch window. This meant that Rosetta’s intended mission to Comet Wirtanen had to be abandoned. In May 2003 a new target comet and launch date for Rosetta were selected.
The adventure began March 2004, when a European Ariane 5 rocket lifted off from Kourou in French Guiana. During a circuitous ten-year trek across the Solar System, Rosetta will cross the asteroid belt and travel into deep space, more than five times Earth’s distance from the Sun. Its destination will be a periodic comet known as 67P/Churyumov-Gerasimenko. The Rosetta orbiter will rendezvous with 67P/Churyumov-Gerasimenko in November 2014 and remain in close proximity to the icy nucleus for about one year, as it plunges towards the warmer inner reaches of the Sun’s domain. At the same time, a small lander will be released onto the surface of this mysterious cosmic iceberg. More than a year will pass before the remarkable mission draws to a close in December 2015. By then, both the spacecraft and the comet will have circled the Sun and be on their way out of the inner Solar System.