Earth to Philae: Lander Once Again Falls Silent

— -- Earth to Philae ... where are you?

The European Space Agency said the Philae comet lander, which recently woke up on the Comet 67-P, has once again fallen silent. Researchers say one theory is Philae may have been nudged by a gas emission from the comet, slightly changing the position of its antenna.

No contact has been made by the solar powered lander since July 9.

Philae lost contact with Earth on November 15 -- 60 hours after it landed on the speeding comet, bounced and came to a final resting place in a shady area lacking the necessary sunlight to keep the lander alive. It woke up again in June as the comet moved closer to the sun.

"The profile of how strongly the Sun is falling on which panels has changed from June to July, and this does not seem to be explained by the course of the seasons on the comet alone," Stephan Ulamec, Philae's project manager, said in a statement.

Aside from the possibility the antenna may have moved, researchers said one of Philae's two receiving units appears to be damaged.

The status of the refrigerator-sized spacecraft is unclear for now as the European Space Agency tries to activate a set of commands that could help Philae wake up and re-commence its scientific measures. If a link is established with Rosetta, the lander would then be able to send the orbiting spacecraft its data, which could then be sent back to Earth.