Scientists are to turn one of the world's most powerful radio telescopes towards Mars in a bid to pick up tiny electrical pulses flickering inside Beagle 2. Success would show that Britain's lost space probe has not crashed and is still functioning silently.
'We have not heard Beagle call home, so we are going to try to see if we can still hear its heartbeat,' said Professor Alan Wells, senior consultant at the British National Space Centre in Leicester. 'We will try to detect the faint electromagnetic emissions produced by its central computer.'
The attempt to listen for Beagle's electrical 'heartbeat' - to be made by astronomers working at the Stanford radio telescope in California - follows three days of failure in raising a signal from Beagle. The £35 million probe was scheduled to land on Mars on Christmas morning after a 250 million-mile journey to the Red Planet. Its mother-ship, Mars Express, was successfully injected into Martian orbit at the same time.
Scientists have since made six attempts to communicate with Beagle, four using America's Martian Odyssey satellite and two using the 250ft Jodrell Bank radio telescope.
No signal has been detected, with yesterday morning's attempt causing most disappointment. It was then daylight on Mars and Beagle's transmitter should have been fully operational for the first time. Still nothing was detected. 'It is not good news,' said Wells.
The probe's creator, Professor Colin Pillinger, said he remained hopeful that the failure to talk to Beagle may have been caused because of problems with its electronic clock. This determines when the spaceship transmits signals to Earth and may have been damaged during the probe's fiery 10-minute descent through the Martian atmosphere. 'We may be listening for Beagle when it is not broadcasting, while at other times it is transmitting when we are not listening,' he said.
In a bid to discover if Beagle is switched on but is refusing to phone home, Stanford astronomers will turn their giant radio dish towards Mars over the next few days. 'The central processor inside Beagle runs all the time,' said Wells. 'It produces very faint emissions - a few thousandths of a watt, possibly only a few millionths. These compare with the 5-watt radio signals transmitted by its main antenna. Nevertheless, it is within the Stanford dish's sensitivity to detect these very faint emissions. This is a telescope built to study objects at the other side of the universe, after all. The radio telescope will not be able to do this straightaway, however. It will take days for Stanford scientists to analyse tapes of the data it picks up from Mars in order to detect a coherent signal from Beagle.'
In addition, there will be two more attempts using Mars Odyssey and Jodrell Bank to pick up direct broadcasts from the spaceship today, and one more tomorrow, although scientists now have little hope of success using this approach. Beagle was either destroyed as it attempted to land or is unable to broadcast to Earth.
'We have to assume the most hopeful scenario,' added Pillinger. 'Beagle has survived but cannot get through to us.' Scientists at the Open University - where Beagle was built - have now set up 'a tiger team' of trouble-shooters to think of ideas for restoring life to Beagle. For example, Beagle's main lid may have jammed or its solar panels may have failed to open properly. As a result, the craft's antenna will have been prevented from opening. Repeat instructions - known as 'blind commands' - could therefore be sent to Beagle this week to try to reopen its lid and panels and to free its antenna.
If this fails, Beagle will get its last chance to talk to Earth next Sunday when Europe's Mars Express reaches its final orbit round the planet. 'Mars Express and Beagle were designed to talk to each other,' said Pillinger. 'The Express has a tenfold better chance of communicating with Beagle than anything else we have tried.'
If it fails, most scientists are likely to assume the worst and conclude the tiny spaceship was destroyed when its heat shield failed or its parachute did not deploy or its shock-absorbing cushions burst.
It will then be left to Nasa to take over the study of the surface of Mars next year. Spirit, the first of America's two Mars Exploration Rovers, is set to land early next Sunday. A second rover will land three weeks later. The six-wheeled robot vehicles - built at a joint cost of £600 million (compared with Beagle's £35m) - will then spend the next six months trundling across the planet in a search for signs that Mars was once - or still is - capable of supporting life.
Neither rover is assured a safe touchdown, however. Three of the five spacecraft due to arrive at Mars this Christmas have now reached the Red Planet's environs. One - Japan's Nozomi probe - has already failed, while Beagle 2 is missing. Only Mars Express has so far performed without flaws.
This proportion - one success for every two failures - is typical of Martian missions. Of the 35 sent to the Red Planet since 1960, only a third have succeeded. The prospects for Spirit and its sister rover Opportunity - due to land on 25 January - are therefore far from assured.
Nevertheless, Professor David Southwood - head of science for the European Space Agency - insisted that Europe, and Britain, should not be daunted in maintaining their commitment to space missions, in particular to Mars. 'America has had many Martian probe failures, but it keeps going back because it considers the exploration of other worlds as something that an advanced society should do. Europe is richer than the US, and we therefore have a duty to look outwards. Mars is a good place to start.'
Mars is set to make another close approach to Earth in 2009 - which gives Europe's space engineers plenty of time to design a new, advanced probe. 'We have to go back,' said Pillinger. 'We have gained a great deal of expertise in building Beagle and we have really captured the public's imagination. I keep getting stopped in shops and petrol stations by people wishing us well.
'The British people want us to succeed in space. We have to go back to Mars, and not just orbit it but land on it, for it is only on the surface of Mars that we will learn if there was life there. And that, after all, is what all of us, scientist or citizen, wants to know.'