LONDON (AP) -- NASA's Mars Odyssey orbiter failed for an eighth time 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.

Mission controllers sent Beagle a message Wednesday 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 the reset command had worked.

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Mars Express Arrives in Orbit, No Word Yet from Beagle 2
Mars Express, Beagle 2 On Final for Red Planet Arrival While mission scientists hope a technical glitch is the problem, they acknowledge that Beagle 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.