Long-lost Philae comet lander is finally found
The European Space Agency has finally found the Philae lander, ending a nearly two-year search for the missing spacecraft.
The Rosetta orbiter spotted Philae in a dark crack on Comet67P's smaller lobe, the Paris-based ESA announced on Monday.
Philae soft-landed on Comet 67P in 2014 to accompany the comet as it hurtled through the inner solar system. But the lander stopped communicating with the Rosetta orbiter after just three days, leaving mission control searching in vain for Philae's precise location.
"This remarkable discovery comes at the end of a long, painstaking search," Patrick Martin, the ESA's Rosetta mission manager, said in a statement.
"We were beginning to think that Philae would remain lost forever. It is incredible we have captured this at the final hour," he added.
(Left and bottom right): Rosetta's lander Philae has been identified in OSIRIS narrow-angle camera images taken on Sept. 2, 2016. (Top right): A Rosetta Navigation Camera image taken on April 16, 2015, is shown for context, with the approximate location of Philae on the small lobe of Comet 67P marked.
The Rosetta mission is slated to wind down on Sept. 30, when Comet 67P will be too far from the sun for the Rosetta orbiter — now circling the comet — to function.
The German Aerospace Center asked space fans to use the hashtag #GoodbyePhilae to send farewell "postcards" to the lander via social media.
Then, on Sept. 2, Rosetta's high-resolution camera captured a surprising image: Philae's main body and two of its three legs, wedged into a deep crack.
Radio ranging data had recently tied Philae's location down to an area spanning tens of meters. But the lower-resolution images that Rosetta captured from larger distances revealed only an array of fuzzy potential candidate objects, many of which were quickly discarded, according to the ESA.
Yet evidence continued to build toward one particular target.
Using Rosetta's narrow-angle camera, the crew took higher-resolution images from just 2.7 kilometers (1.6 miles) away from the comet's surface — an unprecedentedly close range.
The Philae lander emerged into sight.
Philae became the first spacecraft to soft-land on a comet when it touched down on Comet 67P on Nov. 12, 2014.
The spacecraft landed near a spot called Agilkia and bounced around a few times. Then it flew for another two hours before ending up at a location later named Abydos, mission controllers said.
Philae was initially able to send back hours' worth of data from the comet's surface to the Rosetta orbiter. Three days later, though, Philae's primary battery was exhausted and the lander went into hibernation. It only woke up again one more time, communicating briefly with Rosetta in June and July 2015 as the comet moved closer to the sun and more power was available.
Monday's discovery of Philae's precise location will help scientists to better understand the data they did receive from the long-lost lander, ESA scientists said.
"This wonderful news means that we now have the missing 'ground-truth' information needed to put Philae's three days of science into proper context, now that we know where that ground actually is!" Matt Taylor, ESA's Rosetta project scientist, said in a statement.
The ESA said the Rosetta orbiter will be sent on a final one-way mission on Sept. 30 to investigate Comet 67P from up close, including in the open pits in the comet's Ma'at region. The agency said it hoped that key observations from the pits would "reveal secrets" of the comet's interior structure.
Flashback to when Scientists give up hope of restoring contact with Philae: