The Beagle 2 probe still remained silent after controllers with the European Space Agency sent signals to it for a second time late Thursday.
Experts at the agency detected the signal from the Beagle 2 with a radio telescope but failed to get in touch with the probe designed to land on Mars.
Some experts say that hope of a safe touchdown is almost dashed if the Beagle 2 stays out of touch for seven days. But British experts believe that the final conclusion cannot be made until Jan.4 next year.
The Beagle 2 probe was unleashed from the Mars Express six days ago. Working in tandem, the lander and the Mars Express are designed to search for life on the Red Planet, 100 million km from Earth.
Beagle, named after the ship that carried British naturalist Charles Darwin on his scientific discovery in the 1830s, is equipped with a robotic arm to sample surface rock and soil.
Sending a working spacecraft to the Mars has been an odyssey. Of 34 unmanned American, Soviet and Russian missions to Mars since the 1960s, two-thirds have ended in failure.
(Xinhua News Agency December 26, 2003)
