Philae comet lander 'wakes up' from hibernation

 Rosetta's lander Philae has woken up after seven months in hibernation on the surface of Comet 67P/Churyumov-Gerasimenko.

The signals were received at ESA's European Space Operations Centre in Darmstadt at 22:28 CEST on 13 June. More than 300 data packets have been analysed by the teams at the Lander Control Center at the German Aerospace Center (DLR).

"Philae is doing very well: It has an operating temperature of -35ºC and has 24 Watts available," explains DLR Philae Project Manager Dr. Stephan Ulamec. "The lander is ready for operations."

For 85 seconds Philae "spoke" with its team on ground, via Rosetta, in the first contact since going into hibernation in November.

When analysing the status data it became clear that Philae also must have been awake earlier: "We have also received historical data – so far, however, the lander had not been able to contact us earlier."

Now the scientists are waiting for the next contact. There are still more than 8000 data packets in Philae’s mass memory which will give the DLR team information on what happened to the lander in the past few days on Comet 67P/Churyumov-Gerasimenko.

Philae shut down on 15 November 2014 at 1:15 CET after being in operation on the comet for about 60 hours. Since 12 March 2015 the communication unit on orbiter Rosetta was turned on to listen out for the lander.

Four of the lander's solar panels are now getting a good amount of sunlight as the comet falls towards the Sun and the probe is recording data, although the Earth-bound controllers haven't been able to communicate with it long enough to operate its ten instruments as yet.
To rectify that, the Rosetta probe is going to fire up its thrusters and get closer to the comet's surface so that a firm data link can be achieved. The probe will swoop down to orbit around 180km (112 miles) from the comet's surface to establish control of Philae, which has been in hibernation mode since its problematic landing.
When the Philae probe fell towards the comet, it bounced across the surface, ending up at an angle overshadowed by a cliff. At the time, this was viewed as a serious problem, but the landing may prove to be a blessing in disguise.
Had the probe landed in direct sunlight, as planned, the sun's rays would have cooked it by now. Because the lander is partially in the shade, it's still well within operating temperatures and should be able to send back data as the comet heats up, offering clues as to how the heating process affects its chemistry.
It's not known how long the lander will be able to transmit data, but neither it nor Rosetta itself are going anywhere. The two probes will spend the rest of their lives accompanying the comet as it journeys through the cosmos.