Last effort to touch base with Beagle 2

British scientists will make their last attempt to contact the missing Beagle 2 lander on Mars today, after more than four weeks of silence from the craft.

The European Space Agency (ESA) craft, built by scientists at the Open University and Leicester University, went missing when it landed on Mars on Christmas Day.

Last night, they tried to contact Beagle 2 and will try again tonight when Mars Express, the agency's orbiting "mother ship", passes over its landing site. If these fail, the team will have several chances to listen for signals before admitting it has been lost.

The failure of the Beagle 2 mission, which was designed to search for traces of life on Mars, has been overshadowed by the ESA's excited announcement on Friday that Mars Express has proven there is ice-bound water on the planet, as well as frozen carbon dioxide. One ESA expert, Dr John Murray claimed in The Times yesterday they were on the brink of "the most exciting discovery about humanity's place in the Universe since Galileo and Copernicus proved the Earth goes round the Sun".

Their claims sparked off a public relations spat with the US space agency Nasa, which downplayed the European announcement by insisting its Mars Odyssey had found evidence of water in 2002.

Nasa's irritation was deepened by a crisis with its own mission to Mars. The first of their two Mars Rovers, Spirit, has suffered technical failure in its attempt to study rock samples. An identical rover, Opportunity, is due to land on the other side of Mars today.

The row has highlighted serious rivalry between the space agencies over Mars. Last week, George Bush pre-empted a European 30-year plan to land humans on the Moon and then Mars by announcing a Nasa mission for 2015.

However, there is still some cooperation. Shortly, the US Mars orbiter, Mars Global Surveyor, will search for Beagle 2 by photographing the landing site. That could be the only chance to learn what happened to the tiny craft early last Christmas morning.