As hard as ice: Scientists reveal first details of the comet Philae landed on - and say they are 'very confident' the lander WILL come back to life in spring next year
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Esa has revealed the first data from the Philae lander, which shows the surface of the comet was far harder than researchers had expected.
Rosetta's lander captivated the world by landing on the surface of a comet last week, but went into hibernation mode late on Friday when its primary battery ran out of power.
However, today scientists said they are 'very confident' it will wake up again when the comet moves into an orbit where more sunlight hits its solar panels in a few months.
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This was one of the first pictures return by Philae from the surface of comet 67P. Today scientists said they are 'very confident' it will 'wake up' when the comet moves into an orbit where more sunlight hits is solar panels in a few months.
Before going into hibernation at 01:36 CET on 15 November 2014, the Philae lander was able to conduct some work using power supplied by its primary battery.
With its 10 instruments, the mini laboratory sniffed the atmosphere, drilled, hammered and studied Comet 67P/ Churyumov-Gerasimenko while over 500 million kilometres from Earth.
It was controlled and monitored from the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR) Lander Control Center (LCC). Now, the complicated data analysis begins.
DLR's Scientific Director for the project, Ekkehard Kührt, said the team were pleased with the results.
'We have collected a great deal of valuable data, which could only have been acquired through direct contact with the comet,' he said.
'Together with the measurements performed by the Rosetta orbiter, we are well on our way to achieving a greater understanding of comets. Their surface properties appear to be quite different than was previously thought.'
The team responsible for the MUPUS (Multi-Purpose Sensors for Surface and Sub-Surface Science) instrument, which hammered a probe into the comet, estimates that Comet 67P is hard as ice: 'Although the power of the hammer was gradually increased, we were not able to go deep into the surface,' said Tilman Spohn from the DLR Institute of Planetary Research, who is leading the research team.
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'67P/Churyumov-Gerasimenko proved to be a 'tough nut to crack''.
Only the thermal sensors and accelerometers in the anchors that should have fixed Philae to the comet's surface were not used, because they were not deployed during the touchdown.
The team of the SESAME experiment (Surface Electrical, Seismic and Acoustic Monitoring Experiment) can confirm that Churyumov-Gerasimenko is not nearly as soft and fluffy as it was believed to be.
'The strength of the ice founds under a layer of dust on the first landing site is surprisingly high,' says Klaus Seidensticker from the DLR Institute of Planetary Research.
Illustrated here are the various scientific instruments on the Philae lander that were used to study the comet when attached to the surface
The instrument CASSE, which sits in the feet of the lander, was turned on during the descent and clearly registered the first landing as Philae came into contact with the comet.
From additional data, the mechanical properties of Churyumov-Gerasimenko will be derived.
Two other instruments suggest that cometary activity at this landing site is low, as well as revealing the presence of a large amount of water ice under the lander.
The last of the 10 instruments on board the Philae lander to be activated was the Sampling, Drilling and Distribution (SD2) subsystem, which was designed to provide soil samples for the COSAC and PTOLEMY instruments.
It is certain that the drill was activated, as were all the steps to transport the sample to the appropriate oven. COSAC also worked as planned.
Now scientists need to analyse the data to determine whether a soil sample was actually examined in the gas chromatograph.
Overall, the team say they are now confident they will hear form the probe again.
'I'm very confident that Philae will resume contact with us and that we will be able to operate the instruments again,' says DLR Lander Project Manager Stephan Ulamec.
Once the rechargeable secondary battery has been warmed by sunlight again, Philae will restart and the DLR LCC team will take their places at the control consoles again.
'At the first landing site, we would, of course, have had better solar illumination conditions,' says Ulamec.
'Now we are somewhat in shadow, we will need more time to charge.'
One advantage of the shadier landing site in a crater is that the Philae lander will not overheat as quickly as the comet approaches the Sun, but will benefit from the stronger sunlight.
The team managed to rotate the lander during the night of 14/15 November 2014, so that the largest solar panel is now aligned towards the Sun.
Stephan Ulamec believes it is probable that in the spring of 2015, the DLR LCC will once again communicate with Philae and receive data about how the lander is faring on Comet 67P/Churyumov-Gerasimenko.
This incredible series of images shows Philae first's bounce on the surface of comet 67P at the initial landing site, named Agilkia. The times are in GMT. The first four images show the moments leading up to the first landing on the surface, and the final image in the top right shows the direction the probe went in after its first bounce - and scientists are hoping to spot its final resting place in later images
In the summer of 2015, it might be possible that temperatures on the comet will allow Philae's battery to be recharged. 'The orbiter will continue with its overflights to receive any signals from the lander once Philae wakes up from hibernation.'
Of the numerous instruments used by the lander, one was designed to measure the temperature of the comet while a drill was used to collect samples and analyse them.
After a successful manouevre to rotate the largest solar panel out of the shadow of the cliff the probe is wedged against, scientists said there is a chance the probe might wake up again in a few months when the comet is closer to the sun and more sunlight is available.
On Friday, scientists made contact with Rosetta's lander for the last time and managed to turn it towards the sun after using its drill in a last gasp attempt to charge its batteries.
Controllers hope that by exposing one of the larger solar panels to the meagre sunlight that is falling on one of the smaller ones, they can provide enough power to charge its batteries.
They now face an agonising wait to see if, and when, it wakes up. The probe is thought to be resting at an angle in the shadow of a crater wall more than half a mile from its planned landing site.
'We are happy,' said Stefan Ullanec, one of the mission's leaders.
'We even can watch it falling asleep which is a little bit sad but it can give us data that we want to have.'
This incredible image shows the moment the Philae lander bounced off the surface for the first time, on its way to a height of 0.62 miles (1km), before returning to the surface of the comet and bouncing again
Ullanec confirmed the lander was able to send all of its data back to Earth before it 'died' - and celebrated with champagne as the rover's battery power slowly ebbed away.
'Philae has fallen into 'idle mode' - a possibly long silence. In this mode, all instruments and most systems on board are shut down,' the European Space Agency said on its blog in a post entitled Our Lander's Asleep.
The lander's Twitter feed broke the news of its demise, saying: 'I'm feeling a bit tired, did you get all my data? I might take a nap…' - but then added 'I did it! I became the first spacecraft to land on a comet & study it! But it's not over yet…'
They also revealed they had spotted the lander's first landing site, which was captured in images from Rosetta - but still were not sure where it had ended up after two more 'bounces'.
'The rotation of the lander's body could result in more power if one of the larger solar panels can catch the illumination that is falling on the smaller,' said Esa's Mark McCaughrean, senior science advisor.
'All things being equal, the same amount of sunlight falling on a larger panel should result in more power being generated.'
Philae was thought to be partially in darkness beneath a cliff and, crucially, its largest solar panel was not receiving any sunlight.
This means its secondary battery could not be properly charged unless it was rotated after its primary battery ran out of power - which scientists managed to perform before the main battery died.
The probe landed on the comet at around 3.30pm GMT on Wednesday but then bounced twice - first to a height of 0.62 miles (1km) and then to a much lower height of 65ft (20 metres) before coming to rest.
It is also thought to be about 0.62 miles (1km) from its intended landing site.
Scientists described the ground as being more like a 'trampoline' than rock, owing to its soft and powdery texture, which may have caused the unsteady landing of the probe.
The final approach: This image shows comet 67P/CG from a distance of approximately 1.8 miles (3km) from the surface. Philae is now thought to be on the surface but its exact orientation is unknown. It bounced twice before coming to rest
On Wednesday, British scientist Dr Matt Taylor, who played a key role in the mission, said: 'To see this mountaineering effort, that we've descended a lander to the surface of a comet, I can't put words to it. It's beautiful.'
And the expert was so confident of success that he had even had an image of the space probe tattooed on his right leg.
Before the attempt on Wednesday, there was also a good luck message from a man who had once boasted of boldly going into space himself.
Star Trek actor William Shatner sent the team a video in which the 83-year-old said: 'Good luck Rosetta, Philae's gonna land.'
Rosetta has also been aiming to work out the plasma characteristics of the comet (illustrated)
One scientist then described the seven hours of 'terror' they went through to drop the Philae lander 13.6 miles (21.9km) above the comet from its mothership, Rosetta.
Dr Matthew Genge, of Imperial College London, said during the wait: 'This is the most difficult landing in space history - like landing a balloon in a city centre on a windy day with your eyes closed.'
Much of the equipment aboard the lander was switched on for the first time after lying dormant during the ten-year journey.
Klim Churyumov, one of the Ukrainians who discovered the comet 45 years ago and named it, said from mission control in Darmstadt, Germany: 'We saw the first light from this comet in 1969, now we are landing on it. It is a fantastic, outstanding event, the first like it in human civilization.'
New address: The lander announced its arrival on Twitter with this historic tweet for its ten year mission. Throughout this week, mission control have been communicating Philae's status through social networks as the world awaits news of its battery life
WHAT IS THE MIDAS INSTRUMENT?
The Midas instrument on Philae is designed to study the dust particles flung from the comet
Midas is the Micro-Imaging Dust Analysis System. It is designed to study the dust particles flung from the comet as it is heated by the sun and becomes active.
When comets pass through the inner solar system, the ices buried below their dark surface are gradually heated. As this gas streams away from the comet's surface, it drags along dust particles – themselves tiny pieces of rock, ice and organic material.
Sunlight reflected from billions of such particles result in the beautiful dust tails seen from Earth on particle population, size, volume and shape.
Midas is one of several instruments that will study cometary dust. To collect particles Midas has a funnel, which usually points towards the comet.
Behind this is a wheel with sticky targets mounted around its circumference. After dust has been collected, the wheel is rotated to move the dust to the microscope for analysis.
By scanning over the dust grain, line by line, scientists can build a 3D picture. Knowing the size, shape and structure of these particles tells us about how and where these particles formed.
These particles are remnants of when the solar system formed 4.5 billion years ago and could reveal how planets formed, and perhaps on life came to be on Earth.
Ptolemy, a British-built laboratory the size of a shoebox, will be used to analyse the composition of samples from the 4.5 billion-year-old comet.
Scientists hope the £1 billion ($1.6 billion) project will solve some of the greatest puzzles in science - including the origins of life on Earth.
Open University Professor Ian Wright, who helped create Ptolemy, said: 'The idea that comets may have brought the building blocks of life to Earth is one of the reasons why we want to study them.'
Professor Stanley Cowley, planetary scientist at the University of Leicester, added: 'It is an interesting relic from that otherwise inaccessible epoch.'
'It's complicated to land on a comet, and complicated to understand what has happened during this landing,' said Dr Stefan Ulamec, Philae Lander Manager.
Rosetta has chased comet 67P/Churyumov–Gerasimenko through space for more than ten years in what has been described as 'the sexiest, most fantastic mission ever'
LA vs 67P: This image combines a photograph of Los Angeles with an image from the Rosetta spacecraft rendezvousing with Churyumov-Gerasimenko, prior to going into orbit and eventually landing. The comet is around 2.2 by 2.5 miles (3.5 by 4km)
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