Mars probe to dig in search for life

British scientists are to take part in an ambitious European project to dig for life under the surface of Mars using a robot laboratory on wheels.

The European Space Agency has earmarked about 600 million Euros to build the ExoMars spacecraft and its six-wheeled roving robot and a further 175m Euros to launch it in 2011.

A key and unique feature of the robot is a probe that will enable it to drill up to 2 metres under the Martian ground to test for signs of life with a device likened to a pregnancy-testing kit.

The device - called a life marker chip - will contain biological molecules that can readily bind to other organic molecules once they come into contact.

"Essentially we are using biological molecules - proteins - and biological principles to look for biology," said Mark Sims, a principal investigator on the ExoMars mission at the University of Leicester.

"It will provide not only an instrument for space research but will we hope have many terrestrial applications," Dr Sims said.

Like pregnancy-testing kits, the device will exploit the property of some biological molecules, such as antibodies, which can selectively bind to other organic substances much like a key can turn in a particular lock.

"In essence, we are proposing to send hi-tech 'pregnancy test' type devices to Mars," said David Cullen of Cranfield University.

"In other words molecular receptor-based devices that can look for multiple pieces of molecular evidence of life, but the intention and expectation is not to find pregnant Martians," Dr Cullen said.

The ExoMars mission is scheduled for launch in 2011 but it will take at least two years for it to arrive at its final destination because of the immense distances involved.

The European Space Agency has yet to decide on the mission's final configuration, whether for instance it will have an additional orbiting spacecraft as well as the one that lands on the surface.

The US National Aeronautics and Space Administration (Nasa) has two Mars missions planned during the same time period.

One will be launched in 2007 and the other in 2011 but neither will be able to drill more than 50 centimetres (20 inches) below the Martian surface.

Few scientists believe that life could exist on the highly irradiated surface of Mars but there is a possibility that traces of living organisms - organic biomolecules - may be preserved several feet below the surface.

Dr Sims said that if life had once evolved on Mars there is a good chance that the robot laboratory of ExoMars would be able to detect signs of it with the help of its drill.

"The whole basis of ExoMars is to look for biomarkers and the signs of life. It has this drill that can go for 2 metres and we will be able to get at any organics that would have been degraded at the surface," Dr Sims said.

Britain's Particle Physics and Astronomy Research Council announced yesterday that it is spending £1.7m on the initial research needed to develop the instruments and the rover needed for the mission.

Britain is expected to be one biggest funders of the mission, contributing about 17 per cent of the total cost, and British scientists are anxious to take a leading role in building both the rover and its panoply of scientific instruments.

Professor Keith Mason, chief executive of the research council, said that the UK expertise developed during the development of the highly successful Mars Express mission - despite the failure of its Beagle 2 rover - would be invaluable for ExoMars.

"Mars Express has, and still is, delivering outstanding science from orbit around the Red Planet," Professor Mason said.

"It has revealed some amazing facts about Mars and even more amazing images, but we have unfinished business on the surface. To really understand the mysteries of Mars we need 'ground-truth' data and ExoMars will deliver that with the rover and base station," he said.

- INDEPENDENT