The probe, pride and joy of Europe's space community since it lifted off from the plains of Kazakhstan late Monday, "has left the Earth's orbit and is now on its way" to Mars, said Vasily Moroz, head of the Russian team taking part in the mission.

The two-tonne vehicle completed a series of orientation manoeuvres while on a low terrestrial orbit and was then powered into space by a Russian-made Soyuz-Fregat propulsion rocket, raising it to its cruising speed, Moroz told the ITAR-TASS news agency.

Two days into its journey, while travelling at some 30 kilometres a second (650,000 miles an hour), the Mars Express will detach itself from the rocket and travel unassisted in "sleep mode," only contacting Earth once a day, the agency said, quoting officials at the European Space Agency.

An adjustment to the probe's trajectory will be made in September, the ESA sources said, and the historic 400 million kilometre (250 million mile) journey will continue until late December when the Mars Express arrives at its destination and the real work begins.

All being well, after a preliminary circling of Mars, the probe will release its precious cargo, the Beagle-2 lander, on December 25 to land on the planet's surface and start testing the soil.

The mission's holy grail would be the detection of evidence, particularly traces of free-flowing water, indicating that life once existed or even still exists on man's nearest theoretically inhabitable neighbour.

First results are expected to be beamed back in the early weeks of next year.

ESA officials were jubilant after the launch, its director of science David Southwood proclaiming the mission to be "off to a great start."

A member of the Beagle-2 team, John Zarnecki, told British media that "as far as we can tell, everything looks fantastic," but warned that there were "a lot of hurdles to get over before we get to that final goal of landing on the surface of Mars and starting to make scientific measurements."

First of these will be the operation three days into the probe's journey in which Beagle-2 blows the bolts that kept it securely attached during blast-off.

Its extra clamps will have to be removed remotely so that it can be ejected when Mars Express finally arrives at Mars.

But before then it will have to overcome the Great Galactic Ghoul -- the name jocularly used by rocket scientists to denote the apparent curse that has struck previous Mars missions.

The notion of a ravenous phantom lurking in space to devour probes before they reach Mars was originally aimed at the Soviet space programme which lost a long succession of probes aimed at the red planet.

In the 1990s however, the same thing happened to three of the United States' five Mars probes.

This time however the Ghoul will have its work cut out as the Mars Express is due to be followed in short order by two US missions, one scheduled for June 8 and the other provisionally due to lift off on June 25, and by a Japanese probe, the Nozomi (Hope), expected to arrive near Mars early next year.

The Nozomi was originally launched in 1998 and at one point got lost, a presumed victim of the Ghoul, but was later traced, reoriented and set back on course.

SPACE.WIRE