Tweets and the BBC inform us that Philae has woken up:
The European Space Agency (Esa) says its comet lander, Philae, has woken up and contacted Earth.
Philae was dropped on to the surface of Comet 67P by its mothership, Rosetta, last November.
Nothing further yet.
1:50 PM PT: New information from a SciAm article:
http://www.scientificamerican.com/...
The available power—24 watts—is a “good amount,” says Koen Geurts, a member of the landing team at the DLR. “It’s more than enough to communicate and to do science activities,” he says. Philae has probably been awake for several comet days, which each last 12.4 hours, but it is not yet clear how many, he adds.
Assuming the connection with Philae reopens, the first science in coming days will likely be low risk activities, he says, such as taking images and turning on the ROMAP instrument, which measures the comet’s magnetic field.
...
The lander team is currently trying to understand why the link-up from Philae lasted less time then they would have predicted: from a two-hour window, the connection lasted only about 2 minutes. This might be due to uncertainties in Philae’s orientation, or the lander may have moved, Geurts says.
The team in charge of the Rosetta orbiter, which passes the signals from Philae to Earth, will now focus on maximizing the connection, says Matt Taylor, ESA project scientist for the Rosetta mission. “We have to update how we think the lander is oriented when the orbiter comes past,” he says.
In the short term, the orbiter will change its planned orientation to point directly at the lander, he says, and in the long term, the orbiter may eventually change trajectories to aid communications, he adds. "There are still a lot of things to be confirmed with respect to the health of the lander and what we can learn from it. But everyone is very excited,” he says.
And the wonderful xkcd update: