Mars Lander Still MIA

NASA's Mars Odyssey orbiter made its eighth unsuccessful attempt to contact the Beagle 2 probe Wednesday, but scientists say they have not given up hope of hearing from the lander, which was to have touched down on Mars almost a week ago.

On Wednesday, mission controllers sent Beagle a message designed to reset its internal clock. Scientists have said a problem with the clock's software, confusing the timing of its planned transmissions, could be behind its silence. They said it was too early to tell whether Wednesday's reset command had worked.

While mission scientists hope a technical glitch is behind Beagle's failure to communicate, they acknowledge it may have tumbled down a crater on the rocky Martian surface.

Neither Mars Odyssey nor powerful British and American radio telescopes have been able to pick up a signal from Beagle, which was supposed to land Christmas Day after separating from the European Space Agency's Mars Express orbiter.

Scientists will now have to wait until at least Jan. 4, when Mars Express enters an appropriate orbit to hear from the lander.

Mission controllers won't say how long they will keep up hopes of finding Beagle, but say Mars Express has a much better chance of picking up its signal than does Odyssey, because the two crafts' radios have been tested together and shown to link up — unlike those of Beagle and Mars Odyssey.

Scientists also said Wednesday that if Beagle remained intact, it should now switch to an emergency communication mode in which it attempts to contact an orbiter more frequently.

On Tuesday, Mars Express blasted into a new path around Mars, clearing the way for the orbiter to probe deep beneath the planet's surface with its powerful radar. The craft's engine will be fired again Sunday to slow it down and put it into a lower orbit over the planet's poles, positioning it to contact Beagle.

Mars Express went into orbit around Mars early last Thursday — about the same time the British-built Beagle was supposed to land north of the Martian equator, its impact softened by gas bags and parachutes.

The European Mars mission, which blasted off from Kazakhstan in June, is designed to search for signs of past or present life on the planet. Mars Express will orbit the planet for at least one Martian year — almost two Earth years — using its radar to search for signs of water or ice which may once have sustained living organisms.

The 67-kilogram (143-pound) Beagle, if it reached the surface intact, is to sample soil and rocks with a mechanical arm searching for indications of organic matter.