This is great news, just in on Sunday 14 June: seven months after being in deep sleep from having run out power once it landed in the comet's trough, Philae now is bathed in sunlight and has messaged: "Hello Earth! Can you hear me?"
Philae comet lander wakes up, says European Space Agency - BBC News
Philae comet lander wakes up, says European Space Agency - BBC News