ESA Rosetta Comet 67/P Mission: Rosetta Team Uncovers More Secrets

A colour image of Comet 67P/Churyumov-Gerasimenko composed of three images taken by Rosetta’s scientific imaging system OSIRIS in the red, green and blue filters; the images were taken on August 6, 2014 from a distance of 120 km from the comet. 

Image credit: ESA / Rosetta / MPS / OSIRIS Team / UPD /LAM / IAA / SSO / INTA / UPM / DASP / IDA.

The familiar shape of the comet has now had many of its vital statistics measured: the small lobe measures 2.6 × 2.3 × 1.8 km and the large lobe 4.1 × 3.3 × 1.8 km.

The total volume of the comet is 21.4 km3. Rosetta’s Radio Science Instrument has measured its mass to be 10 billion tons, yielding a density of 470 kg/m3.

By assuming an overall composition dominated by water ice and dust with a density of 1,500–2,000 kg/m3, Rosetta scientists show that the comet has a very high porosity of 70–80 percent, with the interior structure likely comprising weakly bonded ice-dust clumps with small void spaces between them.

The OSIRIS instrument has imaged some 70 percent of the surface to date: the remaining unseen area lies in the southern hemisphere that has not yet been fully illuminated since Rosetta’s arrival.

The scientists have so far identified 19 regions separated by distinct boundaries and, following the ancient Egyptian theme of the Rosetta mission, these regions are named for Egyptian deities, and are grouped according to the type of terrain dominant within.

The 19 regions identified on 67P/Churyumov–Gerasimenko are separated by distinct geomorphological boundaries; they are grouped according to the type of terrain dominant within each region. 

Five basic categories of terrain type have been determined: dust-covered (Ma’at, Ash and Babi); brittle materials with pits and circular structures (Seth); large-scale depressions (Hatmehit, Nut and Aten); smooth terrains (Hapi, Imhotep and Anubis), and exposed, more consolidated surfaces (Maftet, Bastet, Serqet, Hathor, Anuket, Khepry, Aker, Atum and Apis). 

Image credit: ESA / Rosetta / MPS / OSIRIS Team / UPD /LAM / IAA / SSO / INTA / UPM / DASP / IDA.

Five basic, but diverse, categories of terrain type have been determined: dust-covered; brittle materials with pits and circular structures; large-scale depressions; smooth terrains; and exposed more consolidated surfaces.

Much of the northern hemisphere is covered in dust. As the comet is heated, ice turns directly into gas that escapes to form the atmosphere or coma.

Dust is dragged along with the gas at slower speeds, and particles that are not traveling fast enough to overcome the weak gravity fall back to the surface instead.

Some sources of discrete jets of activity have also been identified. While a significant proportion of activity emanates from the smooth neck region, jets have also been spotted rising from pits.

The gases that escape from the surface have also been seen to play an important role in transporting dust across the surface, producing dune-like ripples, and boulders with ‘wind-tails,’ the boulders act as natural obstacles to the direction of the gas flow, creating streaks of material ‘downwind’ of them.

“Because comets have very little gravity, dust and gas flow freely into space. But we were surprised to find a cloud of particles orbiting the comet that are large and heavy enough to defy the Sun’s radiation pressure,” said Dr Dennis Bodewits of the University of Maryland.

The scientists were able to make this discovery thanks to OSIRIS’ very sensitive cameras.

“Each pixel is about 30 cm. You couldn’t see a coffee cup, but you could see a large lunchbox. The resolution is about 10 times higher than Google Earth.”

According to the team, 67P/Churyumov-Gerasimenko was releasing the earthly equivalent of 1.2 liters of water into space every second at the end of August 2014.

MIRO (Microwave Instrument for the Rosetta Orbiter)

Credit: ESA

“In observations, made by the Microwave Instrument for Rosetta Orbiter (MIRO), over a period of three months, the amount of water in vapor form that the comet was dumping into space grew about tenfold,” said Dr Sam Gulkis of NASA’s Jet Propulsion Laboratory in Pasadena.

“To be up close and personal with a comet for an extended period of time has provided us with an unprecedented opportunity to see how comets transform from cold, icy bodies to active objects spewing out gas and dust as they get closer to the Sun.”

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: 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.

ESA Rosetta's lander, Philae snaps image of comet 67P/Churyumov-Gerasimenko

A camera aboard Rosetta's lander, Philae, snapped this image of comet 67P/Churyumov-Gerasimenko on Oct. 7.

Credit: ESA /Rosetta /Philae /CIVA

With an icy comet lurking just over its shoulder, a far-flung European spacecraft snapped a selfie in outer space.

The photographer was Philae, a small lander attached to the European Space Agency's (ESA) Rosetta probe.

At the time (Oct. 7), Philae was just 10 miles (16 kilometers) away from the Comet 67P/Churyumov-Gerasimenko, but they're about to get much closer.

On Nov. 12, Philae is scheduled to separate from Rosetta to make an unprecedented touchdown on the comet.

After a decade-long, 4-billion-mile (6 billion km) journey from Earth, Rosetta was awakened from a deep sleep in January.

Then, through a series of carefully choreographed maneuvers, the probe arrived at 67P/Churyumov-Gerasimenko in August and became the first spacecraft to ever orbit a comet.

The new image, released by ESA this week, shows off Rosetta's glinting 52-foot-long (16-meter) solar arrays.

The composition is almost identical to a selfie Philae snapped last month, but at 31 miles (50 kilometers) away, the comet looked much smaller in that photo.

ESA Rosetta sees comet 67P/Churyumov-Gerasimenko darker than charcoal

A spacecraft chasing a comet in deep space has found that its target is surprisingly dark in colour.

Instead of arriving at a bright, reflective, ice-covered heavenly body, the European Space Agency's Rosetta probe found that its target comet, 67P/Churyumov-Gerasimenko (or 67P/C-G), appears darker than charcoal in some wavelengths of light, according to new data collected by an instrument on the spacecraft.

And, so far, scientists working with the Alice instrument on Rosetta have not found any large patches of water-ice on Comet 67P/C-G's surface.

"We're a bit surprised at just how unreflective the comet's surface is and how little evidence of exposed water-ice it shows," Alan Stern, Alice principal investigator at the Southwest Research Institute in Boulder, Colorado, said in a statement.

A four-image montage of Comet 67P/Churyumov-Gerasimenko taken by Rosetta on Sept. 2, 2014.

Credit: ESA/Rosetta/NAVCAM

Researchers expected to see ice patches on the surface of the comet because of the body's distance from the sun.

At the moment, that distance is so great that the sun can't warm ice on the comet's surface, which would turn it into water vapour; therefore, scientists thought there would be ice patches on the comet's surface, according to NASA.

The comet and Rosetta are currently flying about 318 million miles (512 million kilometers) from the sun, on their way to the comet's closest approach to the star, in August 2015.

When Comet 67P/C-G makes its flyby of the sun, Rosetta will be able to measure the way the comet changes.

The new data should help researchers learn more about the origin of comets, remnants from the beginnings of the solar system.

The Alice instrument before flying to space with Rosetta.

Credit: Southwest Research Institute

"As the mission progresses, we will continue to search for surface ice patches and ultraviolet colour and composition variations across the surface of the comet," Lori Feaga, Alice co-investigator at the University of Maryland, said in a statement.

Alice has also identified hydrogen and oxygen in the comet's atmosphere, according to NASA.

In November, the Philae lander, currently tucked inside Rosetta, will fly down to the comet's surface to make measurements while attached to Comet 67P/C-G.

Scientists are currently examining five potential Philae landing sites in order to decide where the lander should park on the comet's face.

The European Space Agency is expected to announce its top choice for a landings site on Sept. 15.

Rosetta launched on its 10-year, 4-billion-mile (6 billion km) journey across the solar system in 2004.

The comet-chasing probe caught up to Comet 67P/C-G in August, after arriving about 62 miles (100 km) from the cosmic body.

Since then, the spacecraft has been maneuvering, getting closer to the comet in anticipation of releasing the Philae lander down to the comet's surface.

ESA Rosetta: Comet 67/P Surface Variations

Image of 67P/Churyumov-Gerasimenko shows the diversity of surface structures on the comet's nucleus. Image courtesy ESA/Rosetta/NAVCAM.

Credit: ESA

A new image of comet 67P/Churyumov-Gerasimenko shows the diversity of surface structures on the comet's nucleus. It was taken by the Rosetta spacecraft's OSIRIS narrow-angle camera on August 7, 2014.

At the time, the spacecraft was 65 miles (104 kilometers) away from the 2.5-mile-wide (4-kilometer) nucleus.

In the image, the comet's head (in the top half of the image) exhibits parallel linear features that resemble cliffs, and its neck displays scattered boulders on a relatively smooth, slumping surface.

In comparison, the comet's body (lower half of the image) seems to exhibit a multi-variable terrain with peaks and valleys, and both smooth and rough topographic features.

A 3-D version of the image is shown below

This anaglyph image of comet 67P/Churyumov-Gerasimenko can be viewed using stereoscopic glasses with red–green/blue filters.

The two images used to make the anaglyph were taken on 7 August 2014 from a distance of 104 kilometres with Rosetta's OSIRIS narrow-angle camera. 

They are separated by 17 minutes.

Credits: ESA /Rosetta /MPS for OSIRIS Team

Launched in March 2004, Rosetta was reactivated in January 2014 after a record 957 days in hibernation.

Rosetta's OSIRIS narrow-angle camera

Composed of an orbiter and lander, Rosetta's objectives are to study comet 67P/Churyumov-Gerasimenko up close in unprecedented detail, prepare for landing a probe on the comet's nucleus in November, and track its changes as it sweeps past the sun.

Comets are time capsules containing primitive material left over from the epoch when the sun and its planets formed.

Rosetta's lander will obtain the first images taken from a comet's surface and will provide the first analysis of a comet's composition by drilling into the surface.

Rosetta also will be the first spacecraft to witness at close proximity how a comet changes as it is subjected to the increasing intensity of the sun's radiation.

Observations will help scientists learn more about the origin and evolution of our solar system, and the role comets may have played in seeding Earth with water.

ESA Rosetta Comet Chaser catches up with comet 67/P today

After an epic, decade-long trek across the solar system, the European Space Agency's Rosetta spacecraft will finally catch up to its target comet early Wednesday (Aug. 6). If all goes according to plan, Rosetta will become the first probe ever to orbit a comet, and you can watch the historic rendezvous live online.

Rosetta is expected to meet up with Comet 67P/Churyumov-Gerasimenko at 4:45 a.m. EDT (0845 GMT) Wednesday, with a crucial 6.5-minute-long engine burn propelling the spacecraft into the comet's orbit.

You can watch a live webcast of all the action at ESA.int beginning at 4 a.m. EDT (0800 GMT), courtesy of the European Space Agency (ESA).

Once Rosetta is in the gravitational grip of the comet, the spacecraft will execute a series of triangular loops around the comet.

Each loop will be about 62 miles (100 kilometers) long and take a few days to complete, mission officials said.



Rosetta blasted off from French Guiana in March 2004. During its 4-billion-mile (6.4-billion-kilometer) chase, the spacecraft zoomed around Earth three times and Mars once for "gravity assists" that helped the spacecraft pick up speed. Rosetta also got up close and personal with two asteroids during its travels.

When Rosetta reached Jupiter's orbit in 2011, ESA engineers put the spacecraft into a deep-space slumber that lasted more than 2.5 years.

Rosetta woke up in January this year for the final phase of its journey to Comet 67P, which is about 2.5 miles (4 km) wide and takes roughly 6.5 years to complete one lap around the sun.

Rosetta has since performed a series of complex maneuvers to slow down and match the comet's pace.

Now, the probe is poised to enter the comet's orbit and travel with it around the sun. Rosetta is also carrying a lander called Philae that's expected to touch down on the comet in November to take samples and study the comet's surface and composition.

ESA Rosetta: Amazing new photo of comet 67/P

OSIRIS narrow angle camera view of 67P/C-G from a distance of 1000 km on 1 August 2014. 

Credits: ESA/Rosetta/MPS for OSIRIS Team MPS /UPD /LAM /IAA /SSO /INTA /UPM /DASP /IDA

As the ESA's Rosetta spacecraft closes to within 1000 km of comet 67P/Churyumov-Gerasimenko, the Rosetta science team has released a new image and made the first temperature measurements of the comet's core.

The temperature data show that 67P is too hot to be covered in ice and must instead have a dark, dusty crust.

The new image was acquired on August 1st at 02:48 UTC by the OSIRIS Narrow Angle Camera onboard Rosetta at a distance of approximately 1000 km. It shows the rough surface of the double-lobed core in amazing detail.

Thermal observations of comet 67P/Churyumov-Gerasimenko were made by Rosetta's visible, infrared and thermal imaging spectrometer, VIRTIS, between 13 and 21 July, when Rosetta closed in from 14 000 km to the comet to just over 5000 km.

At these distances, the comet covered only a few pixels in the field of view and so it was not possible to determine the temperatures of individual features.

But, using the sensor to collect infrared light emitted by the whole comet, scientists determined that its average surface temperature is about -70°C.

Although -70°C may seem rather cold, importantly, it is some 20–30°C warmer than predicted for a comet at that distance covered exclusively in ice.

"This result gives us the first clues on the composition and physical properties of the comet's surface," says VIRTIS principal investigator Fabrizio Capaccioni from INAF-IAPS, Rome, Italy.

Other comets such as 1P/Halley are known to have very dark surfaces owing to a covering of dust, and Rosetta's comet was already known to have a low reflectance from ground-based observations, excluding an entirely 'clean' icy surface.

The temperature measurements provide direct confirmation that much of 67P's surface must be dusty, because darker material heats up and emits heat more readily than ice when it is exposed to sunlight.

"This doesn't exclude the presence of patches of relatively clean ice, however, and very soon, VIRTIS will be able to start generating maps showing the temperature of individual features," adds Dr Capaccioni.

As Rosetta approachs and later orbits the comet, the sensor will study the variation of daily surface temperatures in order to understand how quickly the surface reacts to solar illumination.

In turn, this will provide insight into the thermal conductivity, density and porosity of the top tens of centimetres of the surface—important data to help select a target site for Rosetta's lander, Philae.

ESA Rosetta: Comet chaser nears its target - Comet 67P/Churyumov-Gerasimenko

This artist's impression shows the Rosetta orbiter at comet 67P/Churyumov-Gerasimenko. The image is not to scale. 

Credit: ESA/ATG Medialab

After a decade-long quest spanning six billion kilometres (3.75 billion miles), the European probe Rosetta, will come face to face Wednesday with a comet, one of the Solar System's enigmatic wanderers.

The moment will mark a key phase of the most ambitious project ever undertaken by the European Space Agency (ESA), a 1.3 billion euro ($1.76 billion) bid to get to know these timeless space rovers.

More than 400 million km from where it was launched in March 2004, the spacecraft Rosetta will finally meet up with its prey, Comet 67P/Churyumov-Gerasimenko.

To get there, Rosetta has had to make four flybys of Mars and Earth, using their gravitational force as a slingshot to build up speed, and then entering a 31-month hibernation as light from the distant Sun became too weak for its solar panels.

It was awakened in January.

After braking manoeuvres, the three-tonne craft should on Wednesday be about 100 km from the comet—a navigational feat that, if all goes well, will be followed by glittering scientific rewards.

"It's taken more than 10 years to get here," said Sylvain Lodiot, spacecraft operations manager.

"Now we have to learn how to dock with the comet, and stay with it for the months ahead."

Halley's Comet (1P/Halleys)

Blazing across the sky as they loop around the Sun, comets have long been considered portents of wonderful or terrible events, the birth and death of kings, bountiful harvests or famines, floods or earthquakes.

Astrophysicists, though, see them rather differently.

Comets, they believe, are clusters of the oldest dust and ice in the Solar System, the rubble left from the formation of the planets 4.6 billion years ago.

These so-called dirty snowballs could be the key to understanding how the planets coalesced after the Sun flared into life, say some.

Indeed, one theory, the "pan-spermia" hypothesis, is that comets, by bombarding the fledgling Earth, helped kickstart life here by bringing water and organic molecules.

Until now, though, explorations of comets have been rare and mainly entailed flybys by probes on unrelated missions snatching pictures from thousands of kilometres away.

Exceptions were the US probe Stardust, which brought home dust snatched from a comet's wake, while Europe's Giotto ventured to within 200 km of a comet's surface.

On November 11, the plan is for Rosetta to inch to within a few kilometres of the comet to send down a 100-kilogramme (220-pound) refrigerator-sized robot laboratory, Philae.

ESA Rosetta's Lander, Philae

Anchored to the surface, Philae will carry out experiments in cometary chemistry and texture for up to six months.

After the lander expires, Rosetta will accompany Comet 67P (C-G) as it passes around the Sun and heads out towards the orbit of Jupiter.

Read the full story here

ESA Rosetta Image: Coma surrounds comet 67P/Churyumov-Gerasimenko

The coma of comet 67P/Churyumov-Gerasimenko as seen by OSIRIS camera on board ESA Rosetta. 

The coma covers an area of 150 kilometers across. 

This image was taken on July 25th, 2014 with an exposure time of 330 seconds. 

 The hazy circular structure on the right and the center of the coma are artifacts due to overexposure of the nucleus. 

Credit: ESA/Rosetta/MPS for OSIRIS Team MPS /UPD /LAM /IAA /SSO /INTA /UPM /DASP /IDA

Less than a week before ESA Rosetta's rendezvous with comet 67P/Churyumov-Gerasimenko, images obtained by OSIRIS, the spacecraft's onboard scientific imaging system, show clear signs of a coma surrounding the comet's nucleus.

While the OSIRIS' view of the coma covers an area of 150 kilometers across, its outskirts might reach much farther.

"Even though it sounds like a contradiction, imaging the comet's coma from nearby is more difficult than from far away", says OSIRIS Principal Investigator Holger Sierks from the Max Planck Institute for Solar System Research (MPS) in Germany.

At the end of April, for example, OSIRIS had witnessed a distinct rise of cometary dust production from a distance of more than two million kilometers.

At that time, one pixel in OSIRIS' images corresponded to a region in space covering 2500 square kilometers at the nucleus.

ESA Rosetta's OSIRIS camera

The reflected light from all dust particles seen in this column worked together to create a signal.

Now, as the resolution of OSIRIS images increases, a much smaller region and thus far less dust particles contributes to one pixel.

Nevertheless, a new image dating from July 25th clearly reveals an extended coma shrouding 67P's nucleus.

"Our coma images cover an area of 150 by 150 square kilometers", says Luisa Lara from the Instituto de Astrofísica de Andalucía.

However, most likely these images show only the inner part of the coma, where particle densities are highest. Scientists expect 67P's full coma to actually reach much farther.

Another challenge for OSIRIS is the bright nucleus that outshines the surrounding coma.

While OSIRIS is designed to deal with a controlled overexposure in the region of the nucleus, the stray light from this strong source causes artifacts by the optical system.

In the current image, the hazy bright circular structure to the right of the comet's nucleus is such an artifact. The center of the image located around the position of the nucleus is obscured by overexposure.

The nucleus of comet 67P/Churyumov-Gerasimenko as seen from a distance of 1950 kilometers on July 29th, 2014. 

One pixel corresponds to approximately 37 meters. 

The bright neck region between the comet’s head and body is becoming more and more distinct. 

Credit: ESA/Rosetta/MPS for OSIRIS Team MPS /UPD /LAM /IAA /SSO /INTA /UPM /DASP /IDA

In the next weeks, the OSIRIS team will study how the comet's activity has developed so far in approach.

To this end, data obtained from different distances and with different exposure times need to be correlated.

Meanwhile, new images of the comet's nucleus confirm the collar-like appearance of the neck region which presents itself brighter than most parts of the comet's body and head.

The reason for this feature is still subject to discussion. Possible explanations range from differences in material or grain size to topological effects.

Rosetta is an ESA mission with contributions from its member states and NASA.

Rosetta's Philae lander is provided by a consortium led by DLR, MPS, CNES and ASI.

Rosetta will be the first mission in history to rendezvous with a comet, escort it as it orbits the Sun, and deploy a lander to its surface.

ESA Rosetta OSIRIS: Comet 67P/Churyumov-Gerasimenko

Comet 67P/Churyumov-Gerasimenko was imaged on 14 July 2014 by OSIRIS, Rosetta's scientific imaging system, from a distance of approximately 12 000 km. 

This movie uses a sequence of 36 interpolated images each separated by 20 minutes, providing a 360° preview of the complex shape of the comet. 

The images have been processed using 'sub-sampling by interpolation', a technique that removes the pixelisation and makes a smoother image. 

It does not, however, reveal hidden detail and it is therefore important to note that the comet's surface is not very likely to be as smooth as the processing implies. 

The images suggest that the comet may consist of two parts: one segment seems to be rather elongated, while the other appears more bulbous. 

Credits: ESA/Rosetta/MPS for OSIRIS Team MPS /UPD /LAM /IAA /SSO /INTA /UPM /DASP /IDA

Image courtesy ESA / Rosetta / MPS for OSIRIS Team MPS / UPD / LAM / IAA / SSO / INTA / UPM / DASP / IDA.

The European Space Agency's Rosetta probe has been gearing up to attempt a comet landing.

Recently, the craft discovered something surprising about its intended target, Comet Churyumov-Gerasimenko.

The comet is actually two comets in one, conjoined twins, or more technically, a "contact binary."

As seen in the images captured by Rosetta, Churyumov-Gerasimenko's newly discovered sidekick is slightly smaller and looks as if it was just smashed into the side of the larger mass, like two pieces of clay. Together they measure about 2.5 miles around.

And though it looks and sounds pretty exciting, it's going to make landing a spacecraft on the comet quite a bit more difficult.

After entering orbit around the comet next month, Rosetta will release a landing device called Philae onto the comet's surface in November.

"This form restricts potential landing zones," explained Philae navigator Eric Jurado.

France's National Centre for Space Studies apparently jumped the gun in unveiling images of the comet yesterday, along with a press release.

They were quickly removed, but not before they made their rounds on the Internet. ESA released a statement saying more images will be released late Thursday.

The agency explained the need to at least momentarily withhold information collected via its various missions.

"The aim of a proprietary period is to ensure that the academic teams who spent decades developing and running the sophisticated scientific instruments on-board the spacecraft are able to calibrate and verify the data," explained ESA officials, "as well as reap the rewards of their efforts."

ESA Rosetta: Comet 67P/Churyumov-Gerasimenko re-appears from the gloom

Comet 67P/Churyumov-Gerasimenko as observed on Februaray 28th, 2014, with the ESO's Very Large Telescope. 

Left: To make the comet visible, the scientists superposed several exposures. 

The images were shifted to compensate for the comet's motion. 

The stars appear as broadly smudged lines. Right: Subtracting the starry backgrouns reveals the comet. 

Credit: MPS/ESO

It's back! After comet 67P/Churyumov-Gerasimenko had disappeared behind the Sun and out of the Earth's view last year in October, the target comet of ESA's Rosetta mission can now be seen again.

In the most recent image obtained by researchers from the Max Planck Institute for Solar System Research (MPS) in Germany and the European Southern Observatory (ESO) with the help Very Large Telescope on February 28th, 2014, the comet presents itself brighter than expected for the nucleus alone.

This suggests that frozen ice is already beginning to vaporise and form a very thin atmosphere.

In August, the spacecraft Rosetta will rendezvous with 67P/Churyumov-Gerasimenko and accompany it on its journey around the Sun until at least the end of 2015.

To obtain a measurable image of the comet from a distance of 740 million kilometers, the scientists superposed several exposures taken at slightly different times.

Before, the images were shifted to compensate for the comet's motion.

The stars in the background therefore appear as broadly smudged lines. Subtracting the starry background then revealed the comet: a tiny dot in space.

For researchers, this tiny dot carries valuable information.

Already 67P/Churyumov-Gerasimenko is approximately 50 percent brighter than in the last images from October 2013.

While the comet has moved another 50 million kilometers closer to Earth in this time (and 80 million kilometers closer to the Sun), the increase in brightness cannot be explained by the smaller distance alone.

"The new image suggests that 67P is beginning to emit gas and dust at a relatively large distance from the Sun", says Colin Snodgrass from the MPS.

Colin Snodgrass

This confirms a study presented by Snodgrass and his colleagues last year in which they had compared the comet's brightness as recorded during its previous orbits around the Sun.

The calculations showed that already in March 2014 its activity would be measurable from Earth.

In the coming months, the researchers will continue to monitor how the comet's brightness develops in close collaboration with ESA.

The data will help to assess what conditions await Rosetta upon arrival in August.