Farewell Philae! (VIDEO)

Farewell Philae! 

Scientists give up hope of contacting Rosetta's comet lander... but hope for a final glimpse of it in the summer

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• Scientists at the German Aerospace Centre (DLR) have given up trying to contact the lander, which is stuck below a cliff on comet 67P
• Probe is now covered in dust and is too cold to operate, they say
• Believe there is almost no chance of it re-establishing contact with Earth

By SARAH GRIFFITHS and RICHARD GRAY FOR MAILONLINE

European scientists have given up hope of reestablishing contact with the stricken space probe Philae, which landed on a comet 317 million miles from Earth.

The Philae is now thought to be covered in dust and the comet has now grown too cold for it to operate effectively from its resting place in a hollow beneath a cliff on the comet's surface.

It has been starved of sunlight needed to generate power for beaming back data and images of its frozen home after it bounced off target during its landing, ending up in the shade.

Scroll down for video 

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European scientists have given up hope of restoring contact with space probe Philae (illustrated) which successfully landed on a comet in a pinpoint operation only to lose power because its solar-driven batteries were in the shade

The European Space Agency has said there is now no chance of the probe re-establishing contact with Earth.

But scientists may still get a final glimpse of the probe later this summer when Philae's mothership Rosetta flies over its landing site on comet 67P/Churyumov-Gerasimenko.

 

Rosetta itself will ultimately crash land onto the comet's surface in September.

Scientists at the German Aerospace Centre (DLR) have repeatedly tried to contact the doomed probe since it suffered a bumpy landing and bounced off target thanks to the failure of its harpoon system - with varying levels of success.

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The Philae lander (pictured during its descent towards the comet in November 2014) bounced to a halt on a comet speeding around the sun and has finally been declared dead. A last ditch attempt to contact the probe failed to produce a response last month

In November 2014, controllers released a soundclip of the ominous 'crunch' from vibration sensors in the lander's legs upon from when it hit the comet's dusty surface.

Stephan Ulamec, Philae Project Manager of the DLR said: ‘Unfortunately, the probability of Philae re-establishing contact with our team at the DLR Lander Control Centre is almost zero and we will no longer be sending any commands.'

The lander has not made contact with its Rosetta orbiter since July 9, and a last-ditch attempt failed. 

LISTEN TO PHILAE LAND ON THE COMET 

Sensors in the feet of Rosetta's lander Philae recorded the sound of touchdown as it first came into contact with Comet 67P/Churyumov-Gerasimenko.

The instrument, called SESAME-CASSE, was turned on during the descent.

It clearly registered the first touchdown as Philae came into contact with the comet, in the form of vibrations detected in the soles of the lander's feet.

The European Space Agency confirmed the recording was 'real' audio.

Note that this is an actual sound file; i.e. it is a recording of mechanical vibrations at acoustic frequencies,' it said.

'No modification was necessary except for some technical adjustments (e.g. the .wav format requires amplitude normalisation).

'Actual frequency content and duration are unchanged.'

Klaus Seidensticker from the DLR Institute of Planetary Research said: 'Our data record the first touchdown and show that Philae's feet first penetrated a soft surface layer – possibly a dust layer – several centimetres thick until they hit a hard surface – probably a sintered ice-dust layer – a few milliseconds later.'

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Philae's bumpy landing saw it come to rest at the base of a cliff. This image shows the probe's view of the comet and one of the lander's antennas shortly after landing. However, the probe's batteries only lasted for 60 hours before it ran out of power

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The icy comet 67p/Churyumov-Gerasimenko is now moving further away from the sun, meaning the amount of sunlight that will reach the Philae lander will dwindle. Scientists expect it will become too cold on the comet for the lander to operate by the end of January, meaning all attempts to regain contact will have failed

PHILAE'S BUMPY LANDING 

Rosetta's Philae lander bounced three times on the surface of the comet 67p after its harpoon failed to tether it to the surface.

After a four-billion-mile (6.4 billion km) journey from Earth, the lander successfully detached from the Rosetta spacecraft to travel at 3.3ft (one metre) a second relative to the comet.

The probe initially touched down at a site now known as Agilkia before bouncing in what became a nine hour journey across the surface of the comet.

The lander's first bounce saw it become airborne for seven hours before it bounced to become airborne for another two hours.

It finally settled in a hollow beneath a cliff at its new location, called Abydos. 

In January, DLR scientists sent a command to Philae to spin its flywheel in the hope of knocking dust from its solar panels to see if they could rouse the lander once more.

‘It would be very surprising if we received a signal now,’ Dr Ulamec said. 

After a 10-year journey on board the Rosetta space probe, Philae came to rest on the comet in November 2014 in what was considered a remarkable feat of precision space travel.

It managed to beam back a handful of pictures before its batteries ran out after 60 hours, thanks to its shady position, and could not be recharged.  

The probe woke up in 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. 

This animation shows a close up of the final resting place where the Philae lander is thought to be (Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA)  

Their hopes had been raised after the Rosetta spacecraft appeared to receive a weak signal just before Christmas, but it later turned out not to be a transmission from the lander.

Dr Ulamec said at the time: 'Unfortunately, Philae's silence does not bode well,' and that attempts to contact Philae had been met with a deafening silence.

Scientists believe that one of the lander's two transmitters and one of its two receivers, have both failed and that the second transmitter and receiver are also no longer fully functional.

While the DLR team believes that Philae is likely ice-free, the solar panels that recharge its batteries are probably covered with dust.

A LOT OF FIRSTS AND KNOWLEDGE FOR A FUTURE MISSION 

Several firsts in space were celebrated with the Rosetta mission.

Never before had a spacecraft accompanied a comet on its path around the sun, ot nor landed on a comet's surface and carried out measurements.

'If you are looking for a comparison with other historic missions, these would be the Viking missions, which sent detailed images of Mars for the first time, or the Voyager probes, which allowed a glimpse of the large planets of the Solar System,' Dr Ulamec said.

The Philae landing was a useful lesson: 'We can better adapt future missions to conditions on a comet,' he said.

The last images of Philae will probably be acquired in the summer of 2016, when the Rosetta spacecraft images the lander during close fly-bys.

'When we see how Philae is positioned, we will be able to better interpret certain data, such as the measurements of the Consert radar experiment,' Dr Ulamec explained.

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The Philae lander was due to touch down on comet 67p after being released from the Rosetta spacecraft (illustrated), which is still in orbit around the comet. However, the lander's harpoons failed, meaning it bounced off target and came to rest in a location where it was unable to get enough power

In addition, night-time temperatures can now fall below -180°C (-292°F) as comet 67P/Churyumov-Gerasimenko moves away from the sun, which is much colder than Philae was designed to withstand.

While Philae did not have as much time as initially hoped after landing for experiments, information it has collected is reshaping thinking about comets, and it has been a useful lesson for designing future missions.

Scientists are still pouring over the measurements taken by Philae during its landing, and its brief moment of wakefulness during comet 67p's perihelion.

They expect to get a final glimpse of the lander in the European summer, when the Rosetta spacecraft snaps some pictures during close fly-bys, before crash landing on the comet itself when its mission ends in September.

And in around six years, Philae and Rosetta will near the Earth again when the comet returns to circle the sun again. 

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This image obtained by Philae's CIVA camera 3 shows its view of its final landing site along with one of its feet. The lander is thought to be sitting at an angle that means its solar panels are unable to get enough ligh

ROSETTA'S 'MOST SURPRISING DISCOVERYSO FAR': RESEARCHERS STUNNED TO FIND COMET SURROUNDED BY OXYGEN

Air surrounding the comet 67P Churyumov-Gerasimenko is rich with oxygen,

The surprise discovery made last year may force a rethink of theories about the origins of the Solar System - but does not imply the presence of life.

Experts controlling the ESA's Rosetta orbiter discovered that free oxygen is the fourth most common gas in the atmosphere around Comet 67P.

Its other constituents are water vapour, carbon monoxide and carbon dioxide.

Oxygen is highly reactive and according to current theories should not exist on its own in such quantities.

The team analysed more than 3000 samples collected around the comet between September 2014 and March 2015 to identify the oxygen ( readings illustrated above)

Over vast amounts of time, most of Comet 67P's oxygen should by now have combined with hydrogen to form water, it was thought.

Professor Kathrin Altwegg, project leader for Rosetta's Rosina mass spectrometer instrument, said: 'We had never thought that oxygen could 'survive' for billions of years without combining with other substances.'

While microbes and plants are responsible for most of Earth's oxygen, the new discovery does not mean that Comet 67P is teeming with life.

Instead, scientists believe the comet's oxygen originated very early, before the solar system had even finished forming.

High energy particles are thought to have freed the oxygen by striking grains of ice in the cold and dense birthplace of the solar system, known as a 'dark nebula'.

The oxygen was incorporated into the comet nucleus when it was created some 4.6 billion years ago and has remained ever since, according to the researchers writing in the journal Nature.

Professor Altwegg added: 'This evidence of oxygen as an ancient substance will likely discredit some theoretical models of the formation of the Solar System.'

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