In a last-ditch effort to force the lander to communicate, no further attempts will be made to contact Beagle 2 until Jan. 22. Project managers hope the 10 days of radio silence will force Beagle 2 into an automatic communications mode, called communication search mode 2, in which it sends out regular signals during Mars daylight hours.

Only after 10 days without communications will Beagle 2 -- assuming it is functioning at all -- revert to this backup communications mode. During these 10 days, Mars Express will made no attempt to contact Beagle 2 as it passes over the presumed landing area.

British officials had said the two best scheduled times for Mars Express to communicate with Beagle 2 were on scheduled overflights of the landing area on Jan. 7 and Jan. 12.

Managers said they would continue search efforts until mid-February, after which they would be forced to conclude that Beagle 2, which was last heard from Dec. 19 prior to its separation from Mars Express and subsequent descent through Mars' atmosphere, is lost.