ESA Rosetta Mission: COSIMA collects and analyses Comet 67/P Dust Particles

Two examples of dust grains collected by ESA Rosetta's COmetary Secondary Ion Mass Analyser, (COSIMA) instrument in the period 25-31 October 2014. 

Both grains were collected at a distance of 10-20 km from the comet nucleus. 

Image (a) shows a dust particle (named by the COSIMA team as Eloi) that crumbled into a rubble pile when collected; (b) shows a dust particle that shattered (named Arvid). 

For both grains, the image is shown twice under two different grazing illumination conditions: the top image is illuminated from the right, the bottom image from the left. 

The brightness is adjusted to emphasise the shadows, in order to determine the height of the dust grain. Eloi therefore reaches about 0.1 mm above the target plate; Arvid about 0.06 mm. 

The two small grains at the far right of image (b) are not part of the shattered cluster. The fact that the grains broke apart so easily means their individual parts are not well glued together. 

If they contained ice they would not shatter; instead, the icy component would evaporate off the grain shortly after touching the collecting plate, leaving voids in what remained. 

By comparison, if a pure water-ice grain had struck the detector, then only a dark patch would have been seen. 

These 'fluffy' grains are thought to originate from the dusty layer built up on the comet's surface since its last close approach to the Sun, and will soon be lost into the coma. 

Image courtesy ESA /Rosetta et al

ESA's Rosetta mission is providing unique insight into the life cycle of a comet's dusty surface, watching 67P/Churyumov-Gerasimenko as it sheds the dusty coat it has accumulated over the past four years.

The COmetary Secondary Ion Mass Analyser, (COSIMA), is one of Rosetta's three dust analysis experiments. It started collecting, imaging and measuring the composition of dust particles shortly after the spacecraft arrived at the comet in August 2014.

Results from the first analysis of its data are reported in the journal Nature. "Comet 67P/Churyumov-Gerasimenko sheds dust coat accumulated over the past four years" - Rita Schulz et al. Nature (2015) doi:10.1038/nature14159

The study covers August to October, when the comet moved along its orbit between about 535 million kilometres to 450 million kilometres from the Sun. Rosetta spent the most of this time orbiting the comet at distances of 30 km or less.

The scientists looked at the way that many large dust grains broke apart when they were collected on the instrument's target plate, typically at low speeds of 1-10 m/s.

The grains, which were originally at least 0.05 mm across, fragmented or shattered upon collection.

The fact that they broke apart so easily means that the individual parts were not well bound together. Moreover, if they had contained ice, they would not have shattered.

Instead, the icy component would have evaporated off the grain shortly after touching the collecting plate, leaving voids in what remained.

By comparison, if a pure water-ice grain had struck the detector, then only a dark patch would have been seen.

The dust particles were found to be rich in sodium, sharing the characteristics of 'interplanetary dust particles'.

These are found in meteor streams originating from comets, including the annual Perseids from Comet 109P/Swift-Tuttle and the Leonids from 55P/Tempel-Tuttle.

"We found that the dust particles released first when the comet started to become active again are 'fluffy'.

They don't contain ice, but they do contain a lot of sodium. We have found the parent material of interplanetary dust particles," says lead author Rita Schulz of ESA's Scientific Support Office.

The scientists believe that the grains detected were stranded on the comet's surface after its last perihelion passage, when the flow of gas away from the surface had subsided and was no longer sufficient to lift dust grains from the surface.

While the dust was confined to the surface, the gas continued evaporating at a very low level, coming from ever deeper below the surface during the years that the comet travelled furthest from the Sun.

Effectively, the comet nucleus was 'drying out' on the surface and just below it.

"We believe that these 'fluffy' grains collected by Rosetta originated from the dusty layer built up on the comet's surface since its last close approach to the Sun," explains Martin Hilchenbach, COSIMA principal investigator at the Max-Planck Institute for Solar System research in Germany.

"This layer is being removed as the activity of the comet is increasing again. We see this layer being removed, and we expect it to evolve into a more ice-rich phase in the coming months."

The comet is on a 6.5-year circuit around the Sun, and is moving towards its closest approach in August of this year.

At that point, Rosetta and the comet will be 186 million kilometres from the Sun, between the orbits of Earth and Mars.

As the comet warms, the outflow of gases is increasing and the grains making up the dry surface layers are being lifted into the inner atmosphere, or coma.

Eventually, the incoming solar energy will be high enough to remove all of this old dust, leaving fresher material exposed at the surface.

"In fact, much of the comet's dust mantle should actually be lost by now, and we will soon be looking at grains with very different properties," says Rita.

"Rosetta's dust observations close to the comet nucleus are crucial in helping us to link together what is happening at the very small scale with what we see at much larger scales, as dust is lost into the comet's coma and tail," says Matt Taylor, ESA's Rosetta project scientist.

"For these observations, it really is a case of "watch this space" as we continue to watch in real time how the comet evolves as it approaches the Sun along its orbit over the coming months."

ESA Rosetta Mission: ROSINA water vapour discovery

ESA announced the latest important discovery regarding comet 67P/Churyumov–Gerasimenko.

Rosetta spacecraft orbiting the comet has found the water vapour from its target to be significantly different to that found on Earth.

The discovery made by Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA) fuels the debate on the origin of our planet's oceans.

That's not all, ESA's Rosetta project scientist, Matt Taylor, believes that ROSINA will make more key findings for our understanding of the origin of life. "ROSINA is continuing to take measurements and will for the rest of the mission," Taylor told reporters.

"It is making and will make invaluable detections of the composition of the comets atmosphere, as well as monitoring its density."

ROSINA is a combination of two mass spectrometers and a pressure sensor. The mass spectrometers determine the composition of the comet's atmosphere and ionosphere, measure the temperature and bulk velocity of the gas and ions, and investigate reactions in which they take part.

The ROSINA pressure sensor is capable of measuring both total and ram pressure, and will be used to determine the gas density and rate of radial gas flow.

"It can detect many different kinds of molecules and get to the heart of the constituents of the ancient comet, giving us unprecedented insight into what the conditions were at the beginning of the solar system," Taylor revealed.

Add caption

No single instrument could have the capabilities required to accomplish the ROSINA science objectives, so a three-sensor approach has been adopted.

Each sensor is optimized for a part of the scientific objectives, while at the same time complementing the other sensors.

The latest results were the most anticipated, because the origin of Earth's water is still an open question.

Taylor noticed that those findings have put recent Herschel results into context and agree with results from the Giotto mission.

"It is a very important result and was of the most anticipated, if only that it was one of the first we would be able to make," he said.

In January 2014, ESA's Herschel mission discovered water vapor around dwarf planet Ceres, and in 1986, ESA's Giotto was the first spacecraft to make close up observations of a comet.

Comets in particular are unique tools for probing the early Solar System. They harbor material left over from the protoplanetary disc out of which the planets formed, and therefore should reflect the primordial composition of their places of origin.

ESA Rosetta mission: Philae instruments detect Organic molecules

The ESA Rosetta Philae lander has detected organic molecules on the surface of its comet, scientists have confirmed.

Carbon-containing "organics" are the basis of life on Earth and may give clues to chemical ingredients delivered to our planet early in its history.

The compounds were picked up by the German-built COSAC instrument designed to "sniff" the comet's thin atmosphere.

Other analyses suggest the comet's surface is largely water-ice covered with a thin dust layer.

The European Space Agency (ESA) craft touched down on the Comet 67P on 12 November after a 10-year journey.

Dr Fred Goessmann, principal investigator on the Cosac instrument, which made the organics detection, confirmed the find to reporters, but he added that the team was still trying to interpret the results.

It has not been disclosed which molecules have been found, or how complex they are.

But the results are likely to provide insights into the possible role of comets in contributing some of the chemical building blocks to the primordial mix from which life evolved on the early Earth.

Preliminary results from the MUPUS instrument, which deployed a hammer to the comet after Philae's landing, suggest there is a layer of dust 10-20cm thick on the surface with very hard water-ice underneath.

The ice would be frozen solid at temperatures encountered in the outer Solar System, MUPUS data suggest this layer has a tensile strength similar to sandstone.

"It's within a very broad spectrum of ice models. It was harder than expected at that location, but it's still within bounds," said Prof Mark McCaughrean, senior science adviser to ESA, told reporters.

"People will be playing with [mathematical] models of pure water-ice mixed with certain amount of dust."

He explained: "You can't rule out rock, but if you look at the global story, we know the overall density of the comet is 0.4g/cubic cm. There's no way the thing's made of rock.

"It's more likely there's sintered ice at the surface with more porous material lower down that hasn't been exposed to the Sun in the same way."

After bouncing off the surface at least twice, Philae came to a stop in some sort of high-walled trap.

"The fact that we landed up against something may actually be in our favour. If we'd landed on the main surface, the dust layer may have been even thicker and it's possible we might not have gone down [to the ice]," said Prof McCaughrean.

Scientists had to race to perform as many key tests as they could before Philae's battery life ran out at the weekend.

On re-charge

A key objective was to drill a sample of "soil" and analyse it in COSAC's oven, but, disappointingly, the latest information suggest no soil was delivered to the instrument.

Prof McCaughrean explained: "We didn't necessarily see many organics in the signal. That could be because we didn't manage to pick up a sample, but what we know is that the drill went down to its full extent and came back up again."

"But there's no independent way to say: This is what the sample looks like before you put it in there."

Scientists are hopeful however that as Comet 67P/Churyumov-Gerasimenko approaches the Sun in coming months, Philae's solar panels will see sunlight again.

This might allow the batteries to re-charge, and enable the lander to perform science once more.

"There's a trade off - once it gets too hot, Philae will die as well. There is a sweet spot," said Prof McCaughrean.

He added: "Given the fact that there is a factor of six, seven, eight in solar illumination and the last action we took was to rotate the body of Philae around to get the bigger solar panel in, I think it's perfectly reasonable to think it may well happen.

"By being in the shadow of the cliff, it might even help us, that we might not get so hot, even at full solar illumination, but if you don't get so hot that you don't overheat, have you got enough solar power to charge the system."

The lander's Alpha Particle X-ray Spectrometer (APXS), designed to provide information on the elemental composition of the surface, seems to have partially seen a signal from its own lens cover - which could have dropped off at a strange angle because Philae was not lying flat.

ESA Rosetta mission: Philae lander OSIRIS NAC Camera captures landing data

This collection of images was acquired when Rosetta was about 15km above the surface of 67P

High-resolution pictures have now been released of the Philae probe in the act of landing on Comet 67P last Wednesday.

They were acquired by the OSIRIS Narrow Angle Camera (NAC) on the Rosetta satellite, which had dropped the little robot towards the surface of the "ice mountain".

The images are presented as a mosaic covering the half-hour or so around the "first touchdown," the probe then bounced to a stop about 1km away.

Philae lost battery power on Saturday and is no longer talking with Earth.

Scientists still have not located the craft's current resting spot.

But European Space Agency (ESA) controllers have not given up hope of hearing from the plucky robot again, if it can somehow get enough light on to its solar panels to recharge its systems.

Getting a precise fix on its location, to then photograph its present predicament would provide a better idea of whether this is likely to happen.

The new NAC images will certainly help in this respect because they show the direction the lander took as it bounced away.

At the weekend, ESA presented some fascinating views of the first touchdown taken by Rosetta's navigation cameras, but the OSIRIS NAC system has substantially better resolution.

It's a trap
The new mosaic is produced by the Max Planck Institute for Solar System Research, which operates Osiris.

It details Philae's descent, and the impact mark it leaves on 67P's surface. You then see the 100kg probe heading away on its initial bounce.

NB: All times are in GMT on Wednesday. The resolution is 28 cm/pixel.

This rebound reached hundreds of metres above the comet and lasted almost two hours.

When Philae came back down, it made another small leap, which took it into a high-walled trap.

Telemetry and pictures from the robot itself indicate this location is covered in deep shadow for most of 67P's day.

As a consequence, Philae receives insufficient solar power to re-boot and form a radio link to the orbiting Rosetta spacecraft.

ESA cannot be sure the robot will ever come back to life, but even if it does not the agency says it is "hugely happy" with what was achieved in the more than 50 hours following landing.

The probe managed to complete over 80% of its planned primary science campaign on the surface.

MUPUS

'Rock' hard
This data was pulled off the robot just before its sagging energy reserves dropped it into sleep mode.

Little of the results have so far been released by the various instrument teams. The one major exception is MUPUS.

This sensor package from DLR the German space agency's Institute for Planetary Research deployed a thermometer on the end of a hammer.

It retrieved a number of temperature profiles but broke as it tried to burrow its way into the comet's subsurface.

Scientists say this shows the icy material underlying 67P's dust covering to be far harder than anyone anticipated - having the tensile strength of some rocks.

It also helps explain why Philae bounced so high on that first touchdown.

The 4km-wide comet has little gravity, so when key landing systems designed to hold the robot down failed at the crucial moment, the probe would have been relying on thick, soft, compressive layers to absorb its impact.

However much dust it did encounter at that moment, it clearly was not enough to prevent Philae making its giant rebound.

ESA Rosetta Mission: Philae Lander - Game Over!

The first spacecraft ever to land on a comet has fallen silent, entering a potentially long, cold sleep after running out of power.

The European Space Agency's Philae lander completed its last transmission Friday (Nov. 14) at 7:36 p.m. EST (0036 GMT) before settling into a hibernation state as its batteries ran out.

The probe had been studying the surface of Comet 67P/Churyumov–Gerasimenko for 57 hours when it went to sleep, possibly for good.

Philae landed on the comet on Wednesday (Nov. 12) as part of ESA's historic Rosetta mission.

"It has been a huge success, the whole team is delighted," Philae lander manager Stephan Ulamec of DLR German Aerospace Agency, who tracked the comet landing from ESA's Space Operations Center in Darmstadt, Germany, said in an ESA statement.

"Despite the unplanned series of three touchdowns, all of our instruments could be operated and now it's time to see what we've got."

ESA Rosetta mission: Crippled Philae lander endeavours to transmit relevant data

Animator's picture of Philae on the comet 67/P now appears more idealistic and hugely optimistic.

A report on the Philae spacecraft's verified Twitter feed suggests the probe has successfully "hopped" into a new position which may enable its solar panels to work

There was fresh hope for the Rosetta mission after scientists reconnected with the probe which could be holding key information about how life on Earth began.

The 25-year mission was thrown into jeopardy after the Philae craft bounced away from its landing site on the comet 67P/Churyumov-Gerasimenko and became stuck under a cliff.

Scientists had been working on attempts to find and move the probe before it ran out of battery power.

But on Friday those plans were abandoned and instead they began drilling beneath the surface of the comet in an attempt to get some samples on board for analysis.

ESA Philae landers' instruments listed. Consert, Romap, SD2 and Mupus have been initiated but results are unknown.

Contact with the lander was lost before the data could be sent back to Earth, but late last night Philae re-established radio contact with its orbiting Rosetta satellite and is sending data from the surface.

However, less than an hour later scientist confirmed the lander was "getting tired" and the battery voltage was approaching the limit.

Daniel Scuka, Senior Editor for Spacecraft Operations at ESOC, said on the mission blog: "While the search for the final landing site is still on-going, the lander is racing against the clock to meet as many of the core science goals as possible before the primary battery is exhausted.

"Under the low illumination conditions at Philae's location, it is unlikely that the secondary batteries will charge up enough to enable extended surface operations."

They confirmed that they had received data from Philae, and that the drill had moved up and down, but they were unsure what data they had.

A report on the spacecraft's verified Twitter feed, Philae Lander @Philae2014, suggests the craft has successfully "hopped" into a new position, possibly one that will enable more sunlight to shine on its solar panels.

The first of two messages at about 11pm read: "I just started lifting myself up a little and will now rotate and try and optimise the solar power."

This was quickly followed by another which said: "My rotation was successful (35 degrees). Looks like a whole new comet from this angle."

Philae has imaged three different spots on the comet, it was confirmed.

This may be the sum total of knowledge taken out of the Rosetta Philae lander chapter of the mission.

However, in a less optimistic update just before midnight Mr Scuka added: "On board Philae, system voltage has fallen very close to 21.5V; below that, the battery won't last much longer. At this time, there is insufficient sunlight to provide power."

Rosetta The comet is a remnant from the early solar system and may hold clues about how life on Earth began.

Many scientists believe that comets were the driving force, delivering water and amino acids to the planet during the "bombardment phase" about four billion years ago.

If the link with the probe is lost, there is a faint possibility that the solar panels will begin working again when the comet's orbit brings it closer to the Sun.

"We can only hope that as we approach the Sun, maybe in August, if we don't have dust or a huge coma [a dust cloud around the comet] blocking the Sun, then perhaps there would be a chance we could come back and at least see how the lander is doing," said Valentina Lommats, of the German Space Agency.

Crucially, the team had still not located the lander on Friday. On Thursday, team members said they believed Philae had bounced twice before settling in a crater east of the original landing site.

However, scans by the Osiris camera on board the Rosetta mother ship failed to locate the probe.

Rosetta has now started scanning other areas.

An animated gif of the Philae lander departing from Rosetta on its risky but calamitous journey onto the comet 67/P.

However, scientists were confident that they had collected a huge amount of a data, around 90 per cent of what they were hoping for before the solar panels were needed to extend the mission.

Even if Philae's job is finished, the Rosetta mission is to continue.

Rosetta will remain alongside the comet as it moves closer to the Sun.

Instruments on board will analyse the gases of the tail and the comet's interior, measure dust grains and study its atmosphere and gravity.

The comet will reach its closest distance to the Sun on Aug 13 next year, at about 115 million miles, roughly between the orbits of Earth and Mars.

ESA Rosetta mission: Philae Lander is safe on Comet 67/P - image

A brand new image shows the view from the Philae lander of the surface of the comet

The robot probe Philae that made a historic comet landing is now stable after initially failing to attach to the surface, and is sending pictures.

Efforts are now being made to locate the precise position of the European Space Agency probe on the comet.

Engineers say it may have bounced hundreds of metres back off the surface after first touching down.

Scientists hope the probe will analyse the comet's surface to yield insights into the origins of our Solar System.

The first pictures indicate that the lander is sitting at an angle - perhaps on a slope, or maybe even on its side. But the team is continuing to receive "great data" from Philae.

Esa's Rosetta satellite carried Philae on a 6.4 billion-km (4bn-mile) journey to Comet 67P/Churyumov-Gerasimenko.

ESA Rosetta mission: Philae Lander hanging on to Comet 67/P and broadcasting

ESA Rosetta's robotic probe, Philae Lander made a historic comet landing on comet 67/P and is now said to be stable after initially failing to attach to the surface.

Pictures are coming back from the craft as scientists debate how to proceed.

The OSIRIS camera (Optical, Spectrocopic and Infrared Remote Imaging System) is vital to the mission and it would be a huge disappointment if it fails to function.

ESA Rosetta team made a statement that it is still 'not possible to analyze images from the lander, raising speculation about the state of the craft and its instruments. We are told that the radar is not working.

Has the lander landed upright after bouncing 3 times on the surface? Has it toppled in the soft surface? Has it sunk too deeply into the surface? or are the instruments simply malfunctioning?

The Rosetta team should be able to see a large part of the comet from its current location because, technically, the lander has an albedo a lot larger then the comet.

European Space Agency engineers working on the lander say it may have bounced 3 times, and lifted off hundreds of metres back up off the surface, after first touching down.

Scientists hope the probe will analyse the comet's surface to yield insights into the origins of our Solar System.

The Esa's Rosetta satellite carried Philae on a 6.4 billion-km (4bn-mile) journey to Comet 67P/Churyumov-Gerasimenko.

The robot probe, the size of a washing machine, was launched from the satellite on Wednesday and spent seven hours travelling to the comet.

News of the first landing was confirmed at about 16:05 GMT on Wednesday.

ESA Rosetta mission: Philae Lander has difficulty hanging on to comet 67/P

It was a day when science fiction became science fact. With minute-perfect accuracy, scientists landed a probe on a comet following a ten year journey through the solar system.

The European Space Agency predicted that the first signal would arrive back on Earth at 4.03pm confirming that the Philae lander had touched down after being detached from its mother ship Rosetta.

And at 4.03pm the instruments at control centre in Darmstadt, Germany, sparked into life as the probe made contact and furrowed brows were replaced with beaming smiles and tears.

“We are on the comet!” announced Dr Stephan Ulamec, Philae’s Lander Manager. “We are sitting on the surface and Philae is talking to us.”

However initial jubilation was followed by some anxiety after it emerged that the landing harpoons had not activated, meaning that the probe was simply sitting on the soft surface without being securely attached.

Just hours later Dr Ulamec was forced to admit that the scientists had lost contact with the probe and did not actually know where it was.

"It's complicated to land on a comet. It's also complicated to understand what has happened during the landing. What we know is that we touched down and we landed on the comet. We had a very clear signal and we also received data from the lander. That is the very good news

"The not so good news is that the anchoring harpoons did not fire. So the lander is not anchored to the surface. Did we just land in a soft-sand box and everything is fine? Or is there something else happening. We still do not fully understand what has happened.

"Some of the data indicated that the lander may have lifted off again. It touched down and was rebouncing. So maybe today, we didn't just land once, we landed twice."

Scientists had already spent a nerve-racking 24 hours prior to the landing trying to work out why Philae would not power up after its 10 year slumber in space.

They also quickly realised that the thruster jets, designed to help the comet stay on the surface before the landing anchors are deployed, were not working at all. Without the thrusters it was feared the probe would simply bounce off the surface and back into space.

Despite the concerns, they decided to go ahead with the detachment at 8.35am on Wednesday morning. The probe made a perfect seven hour descent onto the comet 67P/Churyumov-Gerasimenko.

But on Wednesday evening scientists were facing the agonising decision of whether to attempt to activate the anchors again and risk pushing the craft back into space, or leave the probe untethered.

“Our big concern is at the moment is whether we are standing stably. We are considering if we need to retry shooting the anchors. said a spokesman for the Philae lander in Cologne.

Yet the science community was in firm agreement that the £1.3 billion mission had been an incredible success and a huge leap forward for astrophysics.

“It is a milestone for space exploration,” said Prof Tom Marsh of the University of Warwick’s Astronomy and Astrophysics group.

“An incredibly difficult task successfully accomplished at a distance of 520 million miles. It does not get much better than this.

“To think that we have landed on an object often thought in the past to be harbingers of doom is remarkable to me. I am looking forward to what we will now learn from Philae. A truly fabulous achievement.”

ESA Rosetta mission: Comet 67/P image captured by Philae Lander ROLIS instrument

The image shows comet 67P/CG acquired by the ROLIS instrument on the Philae lander during descent on Nov 12, 2014 14:38:41 UT from a distance of approximately 3 km from the surface. 

The landing site is imaged with a resolution of about 3m per pixel.

The ROLIS instrument is a down-looking imager that acquires images during the descent and doubles as a multispectral close-up camera after the landing.

The aim of the ROLIS experiment is to study the texture and microstructure of the comet's surface.

ROLIS (ROsetta Lander Imaging System) is a descent and close-up camera on the Philae Lander. It has been developed by the DLR Institute of Planetary Research, Berlin.

The lander separated from the orbiter at 09:03 GMT (10:03 CET) and touched down on Comet 67P/Churyumov–Gerasimenko seven hours later.

ESA Rosetta mission: Philae lander touches down on Comet 67/P

Philae’s parting image of Rosetta, taken shortly after separation

ESA’s Rosetta mission has soft-landed its Philae probe on a comet, the first time in history that such an extraordinary feat has been achieved.

After a tense wait during the seven-hour descent to the surface of Comet 67P/Churyumov–Gerasimenko, the signal confirming the successful touchdown arrived on Earth at 16:03 GMT (17:03 CET).

The confirmation was relayed via the Rosetta orbiter to Earth and picked up simultaneously by ESA’s ground station in Malargüe, Argentina and NASA’s station in Madrid, Spain.

The signal was immediately confirmed at ESA’s Space Operations Centre, ESOC, in Darmstadt, and DLR’s Lander Control Centre in Cologne, both in Germany.

The first data from the lander’s instruments were transmitted to the Philae Science, Operations and Navigation Centre at France’s CNES space agency in Toulouse.

“Our ambitious Rosetta mission has secured a place in the history books: not only is it the first to rendezvous with and orbit a comet, but it is now also the first to deliver a lander to a comet’s surface,” noted Jean-Jacques Dordain, ESA’s Director General.

“With Rosetta we are opening a door to the origin of planet Earth and fostering a better understanding of our future."

"ESA and its Rosetta mission partners have achieved something extraordinary today.”

“After more than 10 years travelling through space, we’re now making the best ever scientific analysis of one of the oldest remnants of our Solar System,” said Alvaro Giménez, ESA’s Director of Science and Robotic Exploration.

“Decades of preparation have paved the way for today’s success, ensuring that Rosetta continues to be a game-changer in cometary science and space exploration.”

“We are extremely relieved to be safely on the surface of the comet, especially given the extra challenges that we faced with the health of the lander,” said Stephan Ulamec, Philae Lander Manager at the DLR German Aerospace Center.

“In the next hours we’ll learn exactly where and how we’ve landed, and we’ll start getting as much science as we can from the surface of this fascinating world.”

Rosetta was launched on 2 March 2004 and travelled 6.4 billion kilometres through the Solar System before arriving at the comet on 6 August 2014.

“Rosetta’s journey has been a continuous operational challenge, requiring an innovative approach, precision and long experience,” said Thomas Reiter, ESA Director of Human Spaceflight and Operations.

“This success is testimony to the outstanding teamwork and the unique knowhow in operating spacecraft acquired at the European Space Agency over the decades.” 

ESA Rosetta mission: Philae Lander successfully lands on comet 67/P

European ESA Rosetta probes's robot lander, Philae has made the first, historic landing on a comet, after descending from its mothership.

The lander touched down on Comet 67P/Churyumov-Gerasimenko at about 1605 GMT.

There were cheers and hugs at the control room in Darmstadt, Germany, after the signal was confirmed.

It was designed to shine a light on some of the mysteries of these icy relics from the formation of the Solar System.

The landing caps a 6.4 billion-kilometre journey that was begun a decade ago.

"This is a big step for human civilisation," said Jean-Jacques Dordain, the director-general of the European Space Agency (Esa).

Shortly after the touchdown was confirmed, Stephan Ulamec, the mission's lander chief, said: "Philae is talking to us... we are on the comet."

The robot deployed harpoons to fasten itself to the 2.5-mile-wide ball of ice and dust.

Scientists will use Philae to take pictures of the comet's landscape and to analyse its chemical composition.

They are hoping the its surface materials will hold fresh insights into the origins of our Solar System more than 4.5 billion years ago.

ESA Rosetta mission: setback as landing probe slow to wake up

A last-minute glitch in the 10-year mission of ESA's Rosetta spacecraft has ensured a nerve-shredding experience for scientists when they try to land it on a comet.

Rosetta’s Philae landing module did not power up properly when its controllers at the European Space Agency (ESA) switched it on for the first time on Tuesday, causing concern about whether it will work during the landing attempt.

Since it was launched in 2004, Rosetta has travelled four billion miles in its quest to find out, among other things, whether comets could have sparked life on Earth.

If the probe is successfully brought down on the surface of comet 67P/Churyumov-Gerasimenko, it will test samples for amino acids, which could show that similar comets “seeded” Earth with the chemicals needed for life.

If all goes to plan, the Philae probe will detach from Rosetta at 9.03am on Wednesday, with touchdown scheduled for 4.02pm.

Matt Taylor, a Rosetta project scientist, said: “We had a hiccup when we first powered it up. There was a little bit of a delay with it coming online. We don’t know what caused it and we are seeking to find out the cause.

“Obviously it’s a concern for the next step. But everything appears to be working OK now so we’re keeping our fingers crossed.”

Scientists said that the craft was on the right orbit, and the Twitter feed for Philae announced that it was “definitely” warmed up after the early glitches.

Comets throughout history have been associated with ill omen; harbingers of doom which streaked across the skies foretelling plague, death and apocalypse.

But the Rosetta mission could prove that they are actually responsible for all of life on Earth, and possibly life beyond it as well.

The scientists will be particularly excited if they find “left-handed” amino acids, so-called because they have mirror image “right-handed” forms, as those are the type which make up most of life on Earth.

Finding them on a comet would not only give the strongest indication yet that we have alien ancestry, but it would show that Earth-like life could exist on other planets.

John Plane, professor of atmospheric chemistry at the University of Leeds, said: “It’s hugely exciting. One of the great mysteries is whether life came from comets. And if these 'left-handed’ amino acids are found, then clearly these comets will be seeding other planets as well.

“We will be able to look in great detail at what is in the ice.”

There is also a theory that the icy comets brought huge amounts of water to Earth during a period of intense bombardment 4 billion years ago.

Prof Stanley Cowley, of the University of Leicester’s department of physics and astronomy, said: “Comets represent bodies which were left over, essentially unprocessed, from the formation of the solar system some 4.5  billion years ago.

“It is therefore an interesting relic from that otherwise inaccessible epoch.

“Comet impacts are thought to have been one of the principal means by which water was delivered to the early Earth, possibly contributing half the water in our oceans.”

The comet is orbiting at 34,000 miles per hour. It is 360 million miles away from Earth, about half way between the orbits of Mars and Jupiter.

The surface is a jumble of cliffs, boulders and steep slopes. If Philae is released when Rosetta is just a centimetre out of alignment, the lander could fall hundreds of metres away from the chosen touchdown spot.

On Tuesday night, the European Space Agency website said that Rosetta was on course to deliver the probe on the correct trajectory, thus completing the first “critical moment” of the landing.

Dr Daniel Brown, an astronomy lecturer at Nottingham Trent University, said: “Although we have landed on planets, moons and asteroids, it has never been attempted for a nucleus of a comet, and with good reason.

“These objects have a very low gravity, are loosely composed of ice, dust and rocks, and are very irregular in shape. They are temperamental in their behaviour and notoriously difficult to predict.”

The probe is expected to land and fix itself to the two-mile-long comet using harpoons and drills.

It will then begin to analyse the ice, organic material and chemicals present in the comet’s nucleus, and later, as it gets closer to the Sun and begins to heat up, the emissions of gases such as carbon dioxide.

Prof Alan Fitzsimmons from the astrophysics research centre at Queen’s University, Belfast, and colleagues have spent more than a decade studying comet 67P/Churyumov-Gerasimenko and measuring its properties.

“We have waited over 10 years for this day, but with the comet being over 317 million miles away, all we can do now is cross our fingers and hope,” he said.

“The Rosetta mission realises the ambition of mankind to explore our origins and discover what is out there.”

The distance between Earth and the comet means that mission control will not find out whether the landing has been a success for 28 minutes and 20 seconds due to the amount of time it will take the radio waves to travel and transmit the data.

While Philae is on the surface, Rosetta will continue flying in formation with the comet at a distance of about 18 miles.

Rosetta has already been travelling for more than a decade. The craft was launched on March 2, 2004, from Kourou, French Guiana.

It is named after the Rosetta Stone, which provided the key to deciphering hieroglyphics. Scientists hope the spacecraft will provide a similar breakthrough in our understanding of the past.

The Philae probe is named after the island in the Nile where an obelisk was found which also displayed inscriptions in two ancient languages and helped with deciphering the Rosetta Stone.