Scientists have given up hope of restoring contact with the space probe, after its solar batteries were shaded from the sun. The comet landing, in November 2014, was hailed as a remarkable feat of precision space travel.
Image: picture-alliance/dpa/ESA/AOES Medialab
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"Unfortunately, the probability of Philea re-establishing contact with our team...is almost zero," Stephan Ulamec, Philea Project Manager from the German Aerospace Center (DLR) said on Friday.
Ulamec said his team would no longer attempt to send commands to the washing machine-sized lander, adding that "it would be very surprising if we received a signal now."
Dusty, icy terrain
DLR scientists suspect the Philea is covered in grime and too cold to operate after losing power because its solar-driven batteries failed.
The probe made history in November 2014 when it became the first man-made device to make a controlled landing on a comet.
Due to a faulty thruster, the lander did not land in its originally intended location on the "67P/Churyumov-Gerasimenko" comet, which would have provided more sunlight to charge its secondary batteries.
Nevertheless, scientists said the probe still managed to collect data on comet compounds and surface properties, adding that the failed project will help them with future landings.
False hope
Philea woke up last June as the comet approached the sun, giving scientists hope that the lander could complete some experiments that it had not done before its solar-powered batteries ran out.
The comet 67P/Churyumov-GerasimenkoImage: picture alliance/ESA/Rosetta/Philae/ROLIS/DLR
But the lander has not made contact with its mother craft, the Rosetta orbiter, since July 9, and a last-ditch attempt to re-establish contact with the robotic lab has failed.
The DLR team said they would be surprised if they received a signal from Philea now.
Too cold to function
The 4-kilometer-wide (2 1/2 mile) "67P" comet is currently some 222 million kilometers (138 million miles) from Earth - between the orbits of Mars and Jupiter - and is now arcing away from the sun.
Night-time temperatures can fall below 180 degrees Celsius below zero (-292°F), which is much colder than Philae was designed to withstand, scientists said.
Rosetta, which is a mission of the European Space Agency, will continue to study the comet until September before making its own landing on "67P," the ESA said.
mm/rc (AFP, AP, dpa, Reuters)
Philae touchdown - one year on
Lander Philae has been on comet Chury since November 12, 2014. The landing did not go quite as smoothly as hoped. Throughout the past year, Philae only rarely made contact, but manged to send data nonetheless.
Image: ESA via Getty Images
One year ago: Rosetta, Philae together in pursuit of Chury
This twin team travelled through space together for 10 long years. In late summer 2014 spacecraft Rosetta and its lander Philae reached their target - Comet 67P/Churyumov-Gerasimenko. In ever smaller orbits they were circling the celestial object - until the time was ripe for the landing operation.
Image: picture-alliance/dpa/ ESA/ATG medialab
Landing spot selected
Rosetta's OSIRIS camera took this picture of the landing spot on September 14 from a height of 30 kilometers (19 miles). The place had to be free of rocks, hills and valleys for Philae to land safely. Also, it had to be able to get enough sun for the batteries to recharge with the small solar panels on the lander - in order to maintain radio contact to Rosetta.
Image: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA
This is how it should have been
The original plan was that Philae lands on its three legs, fires a Harpune into the comet and fixes itself with screws into the ice and rock. The engineers from the German Aeronautics and Space Research Center (DLR) knew that this would be a tricky task. The landing was the most vulnerable part of the whole operation. Would it succeed?
Image: picture-alliance/dpa/ESA/AOES Medialab
The travellers part - succesfully
The great moment came at 11:57 a.m local time in Darmstadt, Germany when European Space Agency (ESA) mission control received the signal from Rosetta. Philae had successfully departed and was on the way down to its final destination. Now the lander was all on its own.
Image: ESA/J. Mai
Saying good-bye to Philae
Rosetta took this picture shortly after launching Philae. Now the small landing robot is slowly descending towards the comet.
Image: ESA
Philae looking at his future home
Philae took this picture shortly before touchdown with its ROLIS camera - 40 meters above ground. There are rocks and gravel lying around. The big boulder in the upper corner of the picture is about five meters in diameter (15 feet).
Image: ESA/Rosetta/Philae/ROLIS/DLR
Celebrating and then sobering up
When ESA received the signal that Philae had landed, the joy was huge. Shortly after that, mission control realized that everything was not just perfect: It became clear, that Philae was not properly standing on its three legs. Nonetheless, Philae generated a wealth of data from the comet - about its chemical composition and atmosphere - and transmitted it back to earth within the first days.
Image: ESA/J. Mai
Where is Philae?
Once his original battery charge was used up, Philae fell silent. Then it was up to the scientists to analyze the data and make their conclusions. In the meantime, Rosetta continued circling Chury and from time to time even managed to establish short connections with Philae - and send even more data to earth.
Image: CC-BY-SA-ESA/Rosetta/NavCam/IGO 3.0
Age-old oxygen found
The different instruments of Philae and Rosetta discovered all kinds of organic compounds. Most vapor was emitted during the fly-by at the closest proximity to the sun. This picture was taken in July and shows gas emissions. Swiss researchers from the University of Berne even found oxygen which from its nuclear composition indicated that it stemmed from the early times of the solar system.
ESA and DLR engineers are continuing their efforts to establish contact with Philae. They're hoping to find more data that is currently stored on Philae. Rosetta is now closing in on Chury again. It will then probably be easier to make radio contact. Throughout the first half of 2016 scientists are hopeful that Philae may be able to get enough sun to charge its batteries again.
