Time is running out for the comet lander Philae, which has been in hibernation since July 9 last year. For scientists, every moment without contact with the sleeping space probe means coming closer to losing it completely.
This is why the European Space Agency (ESA) is doing all its best to wake up the long-silent comet lander. European scientists will transmit a signal into space on Sunday, Jan. 10, to try to nudge Philae back to life and hopefully restore contact.
"There is a small chance. We want to leave no stone unturned," said Cinzia Fantinati, operations manager from DLR or the German Aerospace Center's Philae control team.
Last Chance To Wake Up Philae
ESA and DLR experts said there are several possibilities as to what Philae's condition on the comet is.
Philae may just be too dusty to power on, so the DLR team plans to take advantage of Philae's momentum wheel called "flywheel" and command it to spin. The flywheel is a device that stabilized the comet lander's descent to comet 67P/Churyumov-Gerasimenko.
"At best, the spacecraft might shake dust from its solar panels and better align itself with the sun," said Koen Geurts, Philae technical manager at DLR's lander control center.
Currently, comet 67P is moving away from the sun, travelling at a speed as fast as 135,000 kilometers (83,885 miles) per hour. At the end of January, the conditions on the comet will be unsuitable for Philae.
Comet 67P will be more than 186 million miles away, making the temperature levels on the surface drop to negative 60 degrees Fahrenheit. The DLR team said this is too cold for Philae's equipment to operate.
Aside from the possibility that Philae might be too dusty, scientists think that one of Philae's two transmitters and one of its receivers have failed. The other transmitter and receiver apparently do not function smoothly, either.
With that, the DLR team hopes that Philae has not yet tilted over or become too dusty. Because comet 67P is active, it is ejecting dust and gas into space. Philae is not safe in its current location.
"Unfortunately, Philae's silence does not bode well," said Stephan Ulamec, DLR Philae lander manager.
If the DLR team's attempts this Sunday are unsuccessful, however, it is possible that they will have to say goodbye to the robot lab for the last time.
Philippe Gaudon, Philae project manager from the French National Space Agency, said the attempt to wake up Philae again is a desperate move.
"It is very unlikely the robot will become functional again," said Gaudon.
Philae's Journey
Dispatched by the Rosetta spacecraft, Philae touched down on comet 67P on Nov. 12, 2014. Philae bounced several times, scraping the crater rim.
Unfortunately, the comet lander entered into safe mode after its batteries ran low due to little sunlight and its landing on a different location than originally intended. Still, Philae was able to communicate magnificent results from comet 67P, scientists said.
In June, Philae woke up from its seven-month hibernation and sent a message home. Comet 67P came closer to the sun, recharging the comet lander. Philae used Rosetta as a relay and sent a "hello" that lasted for 85 seconds. In July, the comet lander fell silent once again.
In the meantime, ESA scientists said the Rosetta spacecraft is expected to remain operational until September this year. Comet 67P's movement away from the sun will affect Rosetta's solar panels, and its battery levels will drop significantly. As the power runs low, Rosetta's scientific instruments will not be functional all at the same time. The spacecraft will be put to sleep by that time.
