The initial landing marked in red. Philae bounced twice, probably out of range of this photo. (ESA)

Remember Philae? In November, the European Space Agency and NASA made history by landing the little robot on a speeding comet.

Rosetta, the orbiter from whence Philae was dropped, is still doing its job -- circling the comet and taking readings from it as they approach a pass of the sun.

But a bad landing (which kept the lander's solar panels out of the sun) meant that Philae's batteries died rather quickly, turning what might have been a four-month mission into one that lasted just a few days.

ESA mission scientists are still holding out hope that the lander will wake up again. They've processed the data it was able to send back during its short life, which included some stunning images of the comet, and hope that proximity to the sun will give Philae's solar panels a much-needed boost. Unfortunately the lander will overheat and die once the comet gets too close to the sun, so Philae's ability to jump through that window of opportunity depends on where it is and how much sun it can get, and when.


An image of a portion of Comet 67P/Churyumov-Gerasimenko obtained on Oct. 30, 2014 by Rosetta's OSIRIS scientific imaging system from a distance of approximately 30 kilometers.

Here's the problem: After almost two months of crunching the data, the mission scientists still aren't sure where Philae ended up.

From pictures of the landing and its aftermath (along with data from the lander itself, which can sense vibration and acceleration among other things), ESA researchers have determined that the lander bounced twice and landed in a dark ditch -- one just off the top of the "head" of the comet's duck-shaped surface.

But the BBC reports that Rosetta has failed to come up with any pictures of its lander. For several days in December the orbiter sought out its lost buddy, but the images beamed back to Earth didn't show any obvious signs of it.

That doesn't mean that Philae has bounced right off into space: In all likelihood, it's just cast into shadow under a high wall that researchers have named the Perihelion Cliff.

Rosetta is at a more distant orbit from the comet now, so the chances that Philae will show up in its scans are slim to none. But with any luck, Philae will wake up and start communicating with Earth sometime in May or June, with enough electricity to operate itself in the fall -- when the comet is closest to the sun.

Scientists expect the comet to get much more active and volatile as it heats up, releasing gas filled with molecules worth studying, so Philae may wake up to a heck of a payday.