When the Philae lander reached the comet 67P/Churyumov-Gerasimenko after a decade in space, the ESA expected it to draw energy from the sun to power its scientific instruments. Unfortunately, it's now stuck in the worst place possible: in the shade, where it's exposed to the sun only three hours per day. According to the probe's lead scientist Jean-Pierre Bibring: "We are exactly below a cliff, so we are in a shadow permanently." In order for the lander to continue collecting samples and crunching data to beam back to Rosetta, it needs at least six to seven hours of daily sunlight. It's been sniffing and analyzing molecules from the comet's surface thus far, but once its main batteries run out on Saturday (they can only power the lander for 64 hours from the time it separated from Rosetta), it'll have to lay in hibernation unless its situation somehow improves.