European Space Probe Heads for Comet

The European Space Agency today launched its Rosetta probe on a 10-year voyage to chase a comet through space and explore its surface, in a mission aimed at unlocking the secrets of the beginnings of the solar system.

An Ariane 5 rocket carrying the Rosetta lifted off from the Guiana Space Centre, Europe's spaceport in Kourou, French Guiana at 07.17 GMT.

After two aborted launch attempts last week, mission scientists in the control centre had an anxious two-hour wait before they knew Rosetta was successfully on its way.

The Ariane 5 orbited the Earth once before the ignition of the launch rocket's "upper stage" began, propelling it deep into space. At 09.33 GMT, ground control said Rosetta had separated from the Ariane rocket and was on its way towards the comet, which it is expected to meet in 2014.

Applause filled the control centre as news came that the final stages of the launch had been a success.

ESA's director-general Jean-Jacques Dordain said communications between the probe and ESA's operations centre in Darmstadt, Germany, had been established.

"Another ESA mission is on its way to explore the universe," he said. "Rosetta is starting a 10-year trip through the solar system. Thanks to missions like Rosetta, space is part of our quest for knowledge and part of our dreams. Long life to Rosetta."

British scientists and engineers have played a leading role the £600m mission. If it succeeds, it will be the first time a spacecraft has landed on a comet.

The ESA mission is aimed at unlocking the secrets of the formation of the sun and planets. Comets are thought to be remnants from the earliest days of the solar system, containing pristine space dust and other material from this crucial period.

ESA experts also believe studying comet Churyumov-Gerasimenko at close quarters could help shed light on how life on Earth began. Comets may have been responsible for bringing water and the "building blocks of life", including carbon, oxygen and nitrogen, to Earth.

David Southwood, ESA's head of science programmes, said: "We're doing something really basic. We're going back to the beginning of time. We are trying to look at the material from which our solar system was made."

No existing rocket is powerful enough to send the spacecraft directly to its destination. Rosetta will swing around Mars and the Earth several times in what ESA refers to as planetary "fly-bys", picking up momentum like a slingshot before breaking free and hurtling off towards its final destination.

In mid-2014, the spacecraft will enter the comet's orbit, slow down and eventually drop the Philae lander, which will conduct 11 experiments on the structural and chemical composition of the comet's nucleus.

The mission, named after the stone that helped archaeologists decipher Egyptian hieroglyphics, is expected to end in December 2015.

Rosetta was initially scheduled to have been launched in early 2003. But the mission was postponed after an upgraded version of Ariane 5 failed on its maiden flight in December 2002. Because of the delay the initial target, the comet Wirtanen, became out of reach for the mission and was replaced with Churyumov-Gerasimenko.

The US led the comet-chasing race with its Stardust spacecraft, which gathered particles from a comet's tail and took pictures of its nucleus. But Rosetta's lander would be the first to touch the nucleus itself.