The spacecraft, Mars Express, is due to be launched from the Baikonur Cosmodrome in Kazakhstan aboard a Soyuz-Fregat rocket operated by the commercial company Starsem.

Liftoff had initially been scheduled for May 23, but was delayed after a fault was found in one of the the spacecraft's electronics modules.

"Of course, it was the most difficult box to remove from the spacecraft," the Mars Express project manager, Rudi Schmidt, said ruefully.

Once it takes up orbit off the Red Planet, Mars Express will release a British-built lander, Beagle 2, designed to take surface samples and search for signs of life.

The United States is also sending two spacecraft, Mars Explorer Rover A and Mars Explorer Rover B.

Rover A was initially scheduled to be launched on May 30, but this will be delayed by at least a week to deal with a last-minute technical hitch, NASA said on April 15. The earliest possible date for the second launch is June 25.

There is a flurry of launches because this year Mars and Earth will be the closest they have been since Neanderthals walked our planet.

That means a trip to Mars can be accomplished in just six months. Mars Express "should enter its Martian orbit on December 26," ESA's press release said.

On August 27, Mars will be within 55,758,006 kilometers (34,646,418 miles) of Earth, the closest in about 73,000 years.

SPACE.WIRE