Nasa has cleared the Phoenix Mars Lander for touchdown on the Martian polar icecap on 26 May.

The craft is now preparing for the final series of actions that will slow it from around 13,000mph before it descends to the surface.

Once there it will sample the North polar ice cap, try to find water and analyse it for signs of life.

Dr Tom Pike, who heads up the UK Phoenix team at Imperial College London, said: "This is a very exciting mission which provides us with the first chance to reach and analyse Martian water, frozen and stored just beneath the surface.

"Our sophisticated imaging and chemical analysis tools will allow us to look at the highest level of detail of any mission to date.

"This should give us the clearest indication so far as to whether Mars could have hosted life at any point in its history."

The probe will use the friction of the Martian atmosphere to slow it down while sheltering behind a heat shield. At 7.8 miles high it will deploy a parachute before descending the final half mile on rocket motors.

"This is not a trip to grandma's house. Putting a spacecraft safely on Mars is hard and risky," said Ed Weiler, associate administrator for Nasa's Science Mission Directorate in Washington. "Fewer than half the attempts have succeeded. "

Once on the ground the probe should be able to operate for five months until autumn sets in and the solar panels lose their effectiveness.