On Christmas night, scientists at the Observatory at Jodrall Banks near Manchester, England, attempted to track the location of the Beagle lander without success.

The next opportunity for contact will come on Friday when NASA’s Mars Odyssey orbiter again crosses over the Beagle’s landing area at about 7:14 p.m. CET. The Jodrell Bank Observatory will have another opportunity to listen for the Beagle’s relatively weak 5 watt signal between 11:40 p.m. and 12:20 a.m. Friday night. Meanwhile, a radio telescope at Stanford University will aid in the search starting on Saturday.

If all else fails, Beagle 2’s mother ship, the Mars Express orbiter, will fly over the landing site during the first week of January. Express is the only device that has been specifically programmed to communicate with the Beagle lander. "The hope is strong that the Mars Express orbiter will be successful in this task," ESA officials said in a statement.

European space officials have sought to assuage fears that the Beagle was destroyed on impact or disintegrated entering the Martian atmosphere, but concern is growing that it may have been lost.

During a press conference Friday morning, the Beagle’s creator, Colin Pillinger (photo), outlined possible reasons for the failure to pick up a signal from the Beagle. It may have crashed, landed in the wrong place, it could have failed to open its lid or its antenna could be facing in the wrong direction. Pillinger said it’s also possible there are problems with the onboard clock that automatically turns the lander’s radio signal on and off. If the clock has changed, the telescopes and probes trying to track the Beagle’s signal could be doing so at the wrong times.

Despite increasingly grim prospects and the fact that two-thirds of all previous Mars missions have failed, scientists involved in the project are not giving up hope yet.

'It's lke waiting for a response to a love letter'

"We're still early days in extra time," Pillinger told reporters. "So we’re not concerned about not being able to contact it." He said the lander could survive for weeks or months on its automated systems, which would still give ESA scientists plenty of time to track it. "If we can contact it, we can pull this thing round. But it's very much like... sending somebody a love letter. You know they've got it and you're waiting for their response."

ESA officials said the British-made Beagle 2 should have landed on Mars at around 3:52 a.m. CET on Thursday morning. The lander should have touched down in Isidis Planitia, a relatively flat area near the Martian equator that may have once been the site of water. If it landed safely and scientists eventually make contact with it, the Beagle 2 will "scratch and sniff" the surface of Mars using an array of tools for collecting and analyzing soil and rock samples in its search for signs of life.

Core of mission still intact

Although the Beagle lander could prove to be the mission’s true audience pleaser, delivering photos from the Martian surface and tantalizing details about the planet’s composition reminiscent of NASA's successful Mars Pathfinder mission in 1997 , it still only represents 10 percent of the total scientific experiments the €300 million Mars Express project is expected to undertake. The vast majority will be conducted by the Mars Express orbiter, which is equipped with a stereo camera and a radar capable of penetrating the Martian surface and will study the atmosphere and composition of Mars in an effort to search for water. The orbiter has successfully entered its intended orbit and will now circle the planet for two years.

"The landing probe on Mars is in essence the icing on the cake," Gerhard Schwehm, an ESA planetary mission official in Darmstadt told the Associated Press. "For the scientists here the orbiter is the most important part of the mission."

Augustin Chicarro, the mission’s scientific director said other instruments on the orbiter would provide "very interesting images, with a global coverage of the planet, which does not exist at present."

Meanwhile, Germany’s top research official, who was present in Darmstadt during the landing window on Christmas morning, also praised the success of Mars Express. "Mars Express has been a great success as it is in a stable and very good orbit," said Research and Technology Minister Edelgard Bulmahn. "We hope the mission is going to be an even greater success yet."