Our final chance to get information from the Philae comet lander probably failed

[Buster's Uncle]

Our final chance to get information from the Philae comet lander probably failed
The Verge
Loren Grush  January 12, 2016






One of the final attempts by the European Space Agency to communicate with the Philae comet lander has most likely failed. The agency sent a command to the spacecraft yesterday in a last-ditch attempt to trigger some kind of response and potentially move the lander, but the vehicle remained silent; it's essentially the same state Philae has been in since 2014, when it first landed on Comet 67P/Churyumov-Gerasimenko. Now it's looking more and more likely that the spacecraft will stay silent until it ends operations sometime at the end of January.

Philae is part of ESA's Rosetta mission — the first endeavor to soft land a spacecraft on the surface of a comet. While Philae did accomplish this task, there were a few hiccups along the way. The spacecraft was supposed to shoot out harpoons that would anchor it to the surface of Comet 67P during its landing. Those harpoons failed to fire, and Philae ended up bouncing on the surface of the comet a few times. The spacecraft ultimately settled in an area that didn't get enough sunlight for its solar panels, so the vehicle ran out of battery power and went into hibernation mode.

At the time, scientists were hopeful. They predicted that once Comet 67P got closer to the Sun sometime in August 2015, Philae might get enough sunlight to wake up again. And indeed, in June, the lander sporadically started communicating with the Rosetta spacecraft, which is orbiting Comet 67P. But then in July, the ESA lost touch with the lander again. It's possible that gas emissions from the comet caused Philae to shift locations again, and its antenna is pointing in a different direction.

ESA scientists have been trying to reestablish communication ever since then. This last attempt was meant to rejigger Philae's momentum wheel, which helps to ensure that the lander's "feet" always point toward the comet's surface. The hope was that this might cause Philae to shift into a more favorable position — but the spacecraft didn't respond. Still, it's possible that Philae did receive the command and moved. Scientists are studying a series of pictures taken by Rosetta during the attempt to see if they can spot any dust clouds. That could indicate that Philae kicked up some material as it changed position.

The lack of contact doesn't look good though, and time is running out for Philae and the ESA team. Comet 67P is moving further and further away from the Sun, and by the end of January, it will be more than 186 million miles away from the star. At that distance, temperatures will be around -60 degrees Fahrenheit — too cold for Philae to operate. The Rosetta orbiter will still continue listening for Philae beyond January, despite the bad odds. But eventually, in September 2016, Rosetta will crash land into Comet 67P, effectively ending the entire mission.


https://www.yahoo.com/tech/final-chance-information-philae-comet-150149785.html