New images of Comet 67P show a small glint of light that may just be the European Space Agency's lost Philae lander, scientists say.
Philae was released by the comet probe Rosetta in November last year to land on the comet, but its final resting place has been unknown, and the lander has not been heard from since its batteries ran out of juice.
Philae, about the size of a home washing machine, bounced away from its intended landing site upon touching down on the 2.5-mile-wide comet, and efforts to locate its exact position have been unsuccessful.
ESA scientists have been poring over Rosetta images of the comet, hoping to spot the lander.
In the latest images, including some taken by Rosetta during its closest approaches to the comet's surface, sharp eyes have detected some features that could be the AWOL lander, they say.
Five bright spots show up in the area where Philae is thought to have come to rest against a cliff wall.
It's believed the shadow of the cliff wall is why the batteries on Philae went dead, keeping sunlight from reaching the lander's solar panels.
Four of the spots are far outside the area scientists believe would take in Philae's bouncing trajectory across the comet's surface, leaving the fifth candidate — a bright spot just meters off that path — the leading candidate.
"This bright spot is visible on two different images taken in December 2014, clearly indicating that it is a real feature on the surface of the comet, not a detector artifact or moving foreground dust speck," says Phillipe Lamy, a member of the team operating Rosetta's high-resolution OSIRIS camera.
There is some hope that, as the comet moves ever closer to the sun, Philae's solar panels may begin to collect enough sunlight to power up the lander's radio, allowing it to "call home" and reveal its exact location.
Until then, ESA scientists say, the only hope is the possibility of Rosetta obtaining even sharper images for study.
"Ultimately, a definitive identification of this or any other candidate as being Philae will require higher-resolution imaging, in turn meaning closer flybys," says Emily Baldwin, editor of the ESA Rosetta blog.
However, that presents its own problems, as so much dust is being thrown off the comet as it nears the sun that Rosetta's navigation system becomes confused if it approaches the comet too closely, the scientists say.
Still, the search will continue, as locating Philae remains a priority for all concerned, says Rosetta project scientist Matt Taylor.
"Knowing where Philae is would provide important context for the lander measurements and valuable information for its possible future operation," he says. "In the meantime, Rosetta is continuing to observe the comet from a range of distances as the comet's activity increases."
