The European Space Agency's lander didn't quite end up where it was supposed to after jumping around a few times after the initial touchdown. This continues to make the mission challenging - and keeps up the suspense.
Image: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA
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Philae's second night on Chury
It seems the suspense around Philae never ends: although the lander touched down on its destination comet Wednesday afternoon (12.11.2014), the lander's problematic position is endangering continuation of the mission.
Due to the lander's position, its solar panels are not receiving enough sunlight to recharge as expected. Scientists are considering how to change the lander's position to better orient at least one solar panel toward the sun. But the clock is ticking ... and Rosetta has again lost touch with the lander, the location of which remains unknown.
Image: ESA/Rosetta/Philae/CIVA
Drill deployed
There were plenty of problems with Philae's landing: the robot bounced twice before coming to rest unsecured. Due to battery life risks, scientists decided deploy the drill that will search for amino acids, water and other building blocks of life. The ESA said the mechanism worked, and the drill went down 25 centimeters - although the link to Rosetta was lost before results could be uplinked.
Image: ESA via Getty Images
'Hole in one'
ESA scientists and engineers now believe that Philae is surrounded by rocks; Philae scientist Matt Taylor referenced a golfing metaphor in speaking of a "hole in one." Not only does Philae's position endanger battery life, but surrounding physical obstructions have made a communication link with Rosetta difficult. Complicating the situation is lack of knowledge on Philae's exact location.
Image: ESA/Rosetta/Philae/CIVA
X marks the spot
Philae initially touched down remarkably close to its intended Agilkia site. But harpoons intended to anchor the craft to the surface failed, and the craft bounced twice - once in an arc 1 kilometer high lasting about two hours, and a much shorter one of seven minutes. Scientists are "having a lot of interesting discussions" on where to look for Philae now, it was said at the ESA press conference.
Image: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA
Elation at mission control
"ESA and its Rosetta mission partners have achieved something extraordinary today," ESA's Director General Jean-Jacques Dordain said on Wednesday. Following a tense seven-hour wait after Philae detached from Rosetta came the news: Philae had touched down on the comet! This released tremendous excitement at the European Space Operation Center in Darmstadt, Germany.
Image: ESA/J. Mai
Busy little robot
Philae managed to take this photo of Rosetta right after separation. The initial success was followed by more good news: scientific data continues to stream down from Rosetta. Photos have shown that the surface of the comet is covered in dust, rocks and debris, and analysis continues of magnetic and topographic measurements.
Image: ESA/Rosetta/Philae/CIVA
Long journey
Philae had traveled through space with Rosetta for 10 years before landing on the comet. The robot, which appears here just after release for landing as a white dot against the vast darness of space, is about the size of a washing machine. Philae's task is to collect images and samples from the comet that could provide information about the origins of life in our solar system.
Image: ESA
A question of perspective
When compared to the city of London, one sees how small Comet 64P/Churyumov-Gerasimenko really is. Considering that the comet moves at a speed of 135,000 kilometers per hour (84,000 miles per hour) - and that Rosetta had to travel 6.4 billion kilometers (4 billion miles) to get to it - the scope of the achievement becomes clear, regardless of whether all goals are achieved.
The historic news keeps resounding: Philae has landed on comet 67P/ Churyumov-Gerasimenko! While this unleashed euphoria in ESA operation centers all over Europe, this was dampened a bit later.
Yes, Philae did land on the comet - three times. The micro-lab that separated from space probe Rosetta first touched ground at 5:03 pm on Wednesday, then bounced twice before it settled into its final position.
Stephan Ulamec, Philae lander manager at the German Aerospace Center (DLR), said at the ESA press conference Thursday afternoon that the lander's first bounce resulted in a 1-kilometer-high, two-hour-long jump in ultra-slow-motion due to extremely low gravity of the comet.
This "huge leap," as Ulamec called it, was followed by a second, smaller bounce of seven minutes.
Naysayers proved wrong
The reason for all this bouncing around: the harpoons that were supposed to anchor Philae to the comet upon landing didn't deploy. "They were supposed to be released when two of Philae's three legs hit the ground, but maybe the ground was too soft to trigger that mechanism," Gerhard Schwehm told DW.
Based on images delivered by Philae, the comet appears to consist of dust, debris, and rocks. Scientists described the surface as a "trampoline."
Comet Chury from Philae 40 meters above the surfaceImage: ESA/Rosetta/Philae/ROLIS/DLR
Schwehm, who is known as one of Rosetta's "fathers" among his colleagues, said that he and other ESA colleagues from Rosetta's early days were gratified when Philae touched down on the comet - because it proved the naysayers wrong.
No more talk of "silly dreams" or "science fiction ideas" - humankind actually put a lander on a comet that's moving through space at 135,000 kilometers per hour, and toward which Rosetta had to travel a cumulative distance of 6.4 billion kilometers to arrive to.
Difficult position
All things considered, it is astounding that Philae originally landed directly in its predetermined landing zone. After the bounces, however, the lander rests in a somewhat precarious position. Only two of its three legs are on the ground, while the third one seems to be hovering in open space. That's because Philae came to rest on a steep slope.
Researchers now have to be extra careful with operations like extracting samples, because Philae could be propelled off the comet again. Another problem with the lander's position is that it appears to be situated against and partially underneath a large ledge.
Since Philae's batteries run on solar power, it can only catch about one hour of sunlight per day, instead of the six or seven hours the scientists had originally hoped for.
In addition, Philae's partially hidden position means it can be in contact with Rosetta only for shorter time periods.
But despite its difficult position, ESA scientists and engineers emphasize that the lander appears to be in good working order.
Origins of life
Still, Philae has already managed to send pictures and started gathering information about the comet's magnetic field and the gases emanating from it. The deeper purpose behind the mission is to gain knowledge about the materials that make up the comet - and thus about Earth's earliest days.
"With this mission, we want to find out whether comets brought complex molecules to the Earth, or whether these molecules originated here," Schwehm explained. "It's supposed to answer questions like why life seems to have formed only on earth."
"And it's a glance into the beginning of our solar system," Schwehm concluded.
