Rosetta, the European spacecraft that will chase down and land on a comet in search of clues to the origins of the Solar System and life, finally began its 12-year mission today after a series of delays.

An Ariane-5 rocket carrying the European Space Agency (ESA) probe blasted off successfully from the Kourou spaceport in French Guiana at 7.17am, setting it on course for a rendez-vous with the comet Churyumov-Gerasimenko in 2014.

The textbook lift-off ended an anxious wait for scientists, who twice had to postpone the launch last week, first because of bad weather and then because a piece of insulating foam broke away from the rocket’s fuel tank.

The mission was also originally scheduled to fly in January last year, but was put back at the last minute because of problems with the Ariane-5 rocket.

Scientists watching at mission control in Darmstadt, Germany, broke into applause as news came through that Rosetta had separated successfully from its final launch stage.

Jean-Yves Le Gall, chief executive of Arianespace, the launch organiser, said: "Our launcher has just placed Rosetta on a liberation orbit which after a trip of ten years will bring it to the comet Churyumov-Gerasimenko."

The mission aims to unlock the secrets of the Solar System's beginnings 4.6 billion years ago, of which comets are largely unchanged relics containing the same materials from which the planets were formed.

It will answer questions about what comets are made of and even whether they could have "seeded" Earth with the water and organic chemicals required for the genesis of life.

On arrival, the probe will orbit the comet’s nucleus, and release the Philae lander to make the first controlled touchdown on a comet’s core. Both Rosetta and Philae will make important measurements of the comet’s composition.

The mother ship takes its name from the Rosetta Stone, discovered in Egypt in 1799, which provided the first key to deciphering hieroglyphics.

Scientists hope that the data it gathers will offer equally critical insights into the origins of the Solar System and terrestrial life. Its lander is named after an island in the Nile where an obelisk critical to the understanding of the Rosetta Stone was found.

Jean-Jacques Dordain, director-general of ESA, said: "Another ESA mission is on its way to explore the universe. Rosetta is starting a ten-year trip through the solar system.

"Now the spacecraft is in the hands of our ground controllers at ESA’s operations centre in Darmstadt. I know these hands are very good. My colleagues have established contact with the probe and they will accompany it during its long trip," he said.

"Thanks to missions like Rosetta, space is part of our quest for knowledge and part of our dreams. Long life to Rosetta."