Philae, the first human-made object to land on a comet, is now permanently inoperative. When it landed in November 2014, it bounced off the surface and tumbled a few times, eventually landing in a shady area where its solar panels couldn’t fully charge.
The team had not heard from Philae since last July so they decided to attempt a risky maneuver to try and dislodge the lander. They sent a signal commanding Philae to spin its internal flywheel in the hope of getting more sunlight on its solar panels. It did not work.
“We have to face reality, and chances get less and less every day as we are getting farther and farther away from the sun,” said lander manager Stephan Ulamec to New Scientist. “At some point we have to accept we will not get signals from Philae anymore.”
Philae was in operation for about 60 hours after it landed and it woke up again last June, confirming that it was in good health. It had several short communications with ground control, but it had difficulties in establishing a stable connection. Rosetta, Philae's orbiting companion, then had to be moved to a higher orbit because Comet 67P/Churyumov–Gerasimenko was getting closer to the Sun and thus more active, moving out of the range of communication.
Philae’s last communication was on July 9, 2015, when it transmitted measurement data; unfortunately, mission controllers were unable to send more instructions for potential investigations, and the probe has been silent ever since. The team will try a few more commands but it’s unlikely it will come back online. The comet is moving away from the Sun, which makes it even less likely for Philae to charge its battery enough to send a signal.
This might be the end for Philae, but its scientific contribution is not over. Scientists are still working on the data that the lander sent, and we might have some close-up shots of Philae in the summer. Rosetta will be crashed on 67P in September, and it will go into a low orbit, over Philae’s predicted location, before meeting its doom. “You should clearly see the lander, and this will help us interpret the data we received in November,” said Ulamec.
[H/T: New Scientist]