Europe's space probe swings by Mars

The European Space Agency's Rosetta probe swooped around the back of Mars early on Sunday, completing a key maneuver in its 10-year mission to meet a distant comet. A photo provided by the agency shows a portion of the spacecraft and one of its solar arrays as it passes Mars.

DARMSTADT, Germany (Reuters) - The European Space Agency's Rosetta probe swooped around the back of Mars early on Sunday, completing a key maneuver in its 10-year mission to meet a distant comet.

The pioneering space probe performed its "swing-by" of the red planet early on Sunday, performing the second of four so-called "gravitational assisted maneuvers" that the craft will complete before reaching its ambitious target in 2014.

The three-ton probe successfully orbited Mars close to the controllers' planned trajectory and at one point came within just 250 km (155 miles) of the planet's surface.

"We are all very happy," said Andrea Accomazzo, Rosetta spacecraft operations manager as employees in the Darmstadt control room applauded the maneuver.

Rosetta will ultimately catch and follow the comet 67P/Churyumov-Gerasimenko in one of the most ambitious projects to date for the European space project.

Controllers had been concerned the probe might face difficulties as it passed through the Martian shadow, losing the solar power source of its instruments and leaving it reliant on a brace of tiny batteries.

But after a 20-minute lull, the probe emerged from the other side of Mars at around 0230 GMT.

The spacecraft, named after the stone which unlocked the secrets of Egyptian hieroglyphics, builds on the success of earlier European comet chasers like Giotto.

"Europe blazed the trail in terms of comet science," ESA's director of science David Southwood told reporters.

"To really understand the solar system we have to go back where it began and it began with comets."

In order to reach the distant comet, the one-billion-euro ($1.3 billion) probe must first pick up speed and achieve the right trajectory, accelerated and assisted by the four swing-bys which use the gravitational pull of planets as a propellant.

The first such maneuver was performed around Earth in 2005, just over a year after the probe was launched from French Guiana on an Ariane 5 rocket.

After Sunday's Mars maneuver, two further trips around Earth, planned for 2007 and 2009, will serve to accelerate the probe until it reaches its final destination.