Philae 'silent' for 10 days, says worried ground control

Paris

Europe's robot lab Philae has fallen "silent" on the surface of a comet zipping towards the Sun, said ground controllers Monday who fear it may have shifted out of radio contact.

"The lander could have moved," the German Aerospace Center (DLR) said in a statement, adding: "even a slight change in its position could mean that its antennas are now obstructed". 

"It is also possible that one of the landers' two radio receiver units is damaged and that one of the transmitter units is not fully functional."

Philae, which touched down on comet 67P/Churyumov-Gerasimenko on November 12 last year, went into hibernation three days later, and woke up again on June 13 for intermittent communications with Earth via its orbiting mothership Rosetta.

The washing machine-sized lander has since called home eight times, the last on July 9, when it uploaded critical data obtained from Philae's prodding and probing of its alien world.

Since then, the robot probe has gone "back to 'silent mode'," said the statement. 

The DLR Lander Control Center "team has been working hard to get back in contact with the lander and operate it to conduct scientific measurements," it added.