Rosetta prepares to map then land on comet.

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http://www.theguardian.com/science/across-the-universe/live/2014/nov/13/rosetta-mission-philae-lander-live-coverage-comet-esa

19m ago07:15
The hunt for Philae continues. It is not yet know exactly where Philae is located on the comet but the thinking is that the lander is not too far away from its original target point.

The lander bounced twice yesterday, finally coming to rest two hours after the original touchdown.

Contact was re-established with Philae this morning around 6:00 GMT, just two minutes after the window opened.

Fred Jansen, Rosetta mission manager, told me, "Yesterday there were people who said that if the lander jumped up and was hovering for an hour or two, the comet would rotate underneath it and then you could be anywhere. But to see the signal so close to the planned time means that we must be close to our original landing spot."

22m ago07:12
The good news from mission control is that scientific data is flowing in, even though the communications link between Philae and Rosetta remains intermittent.

"We have telemetry and massive data already. This is a success," says mission manager Fred Jansen.

28m ago07:05
We still don't know the exact location of Philae. Ingenious Esa engineers are planning to use the radar instrument CONSERT to triangulate its position. The instrument on Rosetta is designed to probe the comet's subsurface using radio waves, which are pinged back to the orbiter by a transponder in the Philae lander.

During the descent, CONSERT showed that the lander was just 50 metres adrift from the targeted landing spot. Esa had planned for the error in position being up to 500 metres.

Of course, that was before those two slow-motion bounces. Magnetic field data from Philae's ROMAT instrument revealed three "landings". The first was almost exactly on the expected arrival time of 15:33 GMT. But as we now know the anchoring harpoons did not fire and Philae rebounded.

In the weak gravity of the comet it took about two hours for the lander to return to the surface after that first bounce. It touched down for a second time at 17:26 GMT, then bounced again before finally coming to rest at 17:33.

37m ago06:57
We've been promised four more pictures from the press conference at 1pm GMT forming the first 360° panorama of the surface. Worryingly, an Esa official has let slip that there "may" not be a horizon visible in those either.

41m ago06:52
Philae may be wedged in a hole

If Philae is wedged in a hole, this could be a serious problem because its initial battery life is only 60 hours. Thereafter it must rely on solar power. "We are definitely not in the open," says mission manager Fred Jansen.

Discussions are taking place about whether to deploy the lander's drills and other moveable parts to nudge it into a better position.

41m ago06:52
The image released this morning comprises two CIVA images from the full panorama of six images that will be released at 1pm. These will show the other two legs of the lander, and provide a full panorama of the landing site. CIVA itself comprises six micro cameras dotted around Philae's body.

46m ago06:47
There will be a press conference in Darmstadt at 1pm GMT revealing what the scientists have gleaned from the data coming back from Philae. We'll livestream that and report the highlights here. The suspicion is that the lander is in a crater or facing a cliff.

A mosaic of two images taken by the lander's CIVA camera shows one of Philae's legs and the craggy surface. Esa had been expecting a view of the horizon ... "We're either looking into a ditch or we are against a wall," project scientist Matt Taylor has told our astronomy blogger Stuart Clark.

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First image from the surface of Comet 67P/Churyumov-Gerasimenko from the Rosetta million's lander Philae

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http://www.bbc.com/news/science-environment-30034060

Touching down on a comet is mind-blowing in itself, but try picturing how the tiny Philae lander has then bounced around its new home.

From what we know, the lander rose hundreds of metres above the surface at one stage and remained in flight for nearly two hours. One might say it was airborne, except that the comet has no air.

In any event, it may have risen vertically or drifted sideways - we should hear later. Either way, while Philae was off the surface, the comet will have rotated beneath it. Each rotation takes about 12 hours which means the lander may effectively travelled across one-sixth of the comet's surface.

By the time it came down again, the original landing zone - chosen for its relative safety and ideal amount of sunshine - was left far behind. The lander is now in different, undetermined area that may prove far more hazardous.

The first picture is confusing, but suggests Philae is sitting at an angle. Everyone here is hungry for more news.

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http://www.theguardian.com/science/across-the-universe/live/2014/nov/13/rosetta-mission-philae-lander-live-coverage-comet-esa

Philae is thought to be resting somewhere in candidate landing site B, shown here. The exact location of the lander is unknown but it is probably toward the bottom right of the image. Originally this landing site was rejected by Esa on account of the large boulders and the poorer illumination than site J, which was chosen and became known as Agilkia.

Drilling for samples will be risky


Philae has been designed to achieve its main science objectives within its initial 60-hour battery life. When asked at the press conference what was the absolutely fundamental investigation to be performed, Jean-Pierre Bibring – lead scientist for the lander – said it was to analyse the organic molecules on the comet.

To do that, it must get samples into its PTOLEMY, COSAC and CIVA instruments. There are two ways to do this: by sniffing and drilling. Sniffing involves opening the instruments and allowing molecules from the comet's surface to drift in. The instruments are already acquiring samples like this and returning data.

Drilling is much riskier because it could topple the lander. Newton's third law of motion says that for every action there is an equal and opposite reaction. In the minuscule gravity of the comet, any movement by Philae's tools could cause the whole lander to shift or even take off again.

The drill turning one way will make Philae want to turn the other. Pushing down into the surface will push the lander in the opposite direction.

"We don't want to start drilling and end the mission," says Bibring. So they will try this only towards the end of the 60-hour nominal mission.

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http://blogs.esa.int/rosetta/2014/11/14/how-and-where-is-philae/

→How (and where) is Philae?
   

The current status of Rosetta's lander Philae was discussed live during a Google Hangout this afternoon, together with scientists and engineers from the mission teams at ESA and partner agencies. The teams are very happy about the lander and the successful functioning of all instruments that were operated so far.

As reported by Stefan Ulamec, the lander manager from DLR, last night a sequence of commands to operate a number of instruments was uploaded to the lander. The resulting data were downlinked earlier today and the scientists are currently analysing them and trying to figure out what they mean.

One of the instruments that was activated during this sequence is MUPUS, the MUlti-PUrpose Sensors for Surface and Sub-Surface Science, which has hopefully penetrated and hammered into the surface of the comet to test its thermal and mechanical properties.

Another instrument that was deployed during this sequence is APXS, the Alpha Proton X-ray Spectrometer, to probe the elemental composition of the comet's surface.

They also conducted new measurements with CONSERT (COmet Nucleus Sounding Experiment by Radio-wave Transmission), an instrument that is operated both on the lander and the orbiter. The CONSERT data will be used to get a better estimate of the lander's position, which has not been extactly identified yet.

The search for Philae is on, using not only CONSERT data, but also imagery from Rosetta - both from the OSIRIS imaging system and the navigation camera (NavCam) - as well as the data collected locally by the lander.

Holger Sierks, Principal investigator of OSIRIS, mentioned that images taken after touchdown are still to be downlinked; as soon as the images become available to the team, they will try to locate not only the lander's current position but also its bouncing trajectory after the first touchdown. Meanwhile, they are continuing to image the surface of the comet with OSIRIS.

Another instrument that was operated on the lander is SD2, the sampling, drilling and distribution (SD2) subsystem, which was activated and started drilling. Philippe Gaudon, manager of Philae's Science, Operations and Navigation Centre (SONC) at CNES, Toulouse, explained that the mechanism was working well, as they saw the drill go 25 cm below its base plate.

Shortly after, however, the link with Philae was lost - as expected, since the lander had moved below the horizon from Rosetta - so the results of this first drilling session should be available in the evening.

If successful, the first sample collected by the drill is scheduled to be fed to COSAC, the COmetary SAmpling and Composition experiment that will analyse the cometary material looking for organic compounds and measuring the chirality of the molecules.

A crucial uncertainty at the moment is the duration of the primary battery, which may run out before the end of this final block of the first science sequence. As explained by Valentina Lommatsch from the Lander Control Center at DLR, simulations that were run last night indicate that the battery might still have around 100 Wh left, which may be just enough to complete the sequence and relay back the data if the temperature of the battery does not decrease. The outcome will be known for sure only late this evening.

As for the position of the lander, Valentina Lommatsch explained that all three of Philae's legs are on the ground, but the sunlight received at the solar panels is very low, which is likely due to the local topography of the site of final touchdown. As reported by Stefan Ulemec, one of the panels is receiving sunlight for about one hour and twenty minutes and two more panels for about twenty-thirty minutes every comet day (which lasts 12.4 hours). They also confirmed that the lander has not moved since the third touchdown, after which the first CIVA-P panorama was taken.

The orbiter is doing great by the way, as reported by Andrea Accomazzo, ESA Rosetta Flight Director at ESOC. The team had to manoeuvre Rosetta to keep visibility with the location on the comet where Philae is, and the signal received from the lander is very stable. Of course, everyone is looking forward to finding its exact location on the comet's surface and, most importantly, to hearing back from Philae tonight.

Matt Taylor, Rosetta project scientist at ESA, mentioned that both orbiter and lander have been performing outstanding measurements so far, at the very cutting edge of science. Everyone's looking forward to the first scientific results, which will be presented next month at the Planetary Sciences Section of the American Geophysical Union.

Looking forward to the scientific output of the mission are also the two guests who joined the Google Hangout from the United States, Jeff Grossman and Gordon Johnston from the OSIRIS-REx Program at NASA, who are eagerly learning from Rosetta in sight of their coming asteroid study and sample return mission, planned to launch in a couple of years.

But for the moment, all eyes are turned on Philae: both on the short term, waiting to get the signal back from the lander tonight, and on the longer term. Even if its current location does not offer optimal exposure to sunlight to fully recharge the secondary batteries, it is possible that, as the comet approaches to the Sun, the illumination will increase and Philae will once more wake up and talk to us.

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http://www.newscientist.com/article/dn26571-philaes-hop-skip-and-jump-across-comet-67p.html

Philae's hop, skip and jump across comet 67P
15:02 17 November 2014 by Jacob Aron




The European Space Agency's comet-hopper Philae was caught in action as it travelled above the surface of comet 67P/Churyumov–Gerasimenko last week. ESA has just released this composite image showing Philae's journey as seen by the orbiting Rosetta spacecraft.

Philae first touched down at 1535 GMT on 12 November before bouncing away from 67P, perhaps as high as 1 kilometre. The first three inset images, from left to right, show Philae as it descended towards the surface. The fourth image, taken shortly after the bounce, show the impression in the surface left by Philae – one that wasn't there in a picture taken at 1518 GMT.

The picture on the far right shows Philae ominously flying over a shadowed region. The spacecraft came to rest again at 1725 GMT, bounced a second time, and reached its final resting point at 1732 GMT. ESA has still not established the location of this last landing, but it is working hard to compare images taken by Philae on the ground with images and triangulation data from Rosetta.

The lander is now in hibernation mode. Whether or not it wakes up again will depend on getting enough sunlight on its solar panels to recharge its batteries.



Another image, released yesterday, shows a low-resolution view of Philae's first bounce. You can see the dust cloud thrown up from the surface, along with the lander and its shadow – taking up just a few pixels.

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http://www.newscientist.com/article/dn26612-rosettawatch-homing-in-on-philaes-resting-spot.html

#Rosettawatch: homing in on Philae's resting spot
17:39 25 November 2014 by Jacob Aron


It has been two weeks since the Philae spacecraft touched down on comet 67P/Churyumov-Gerasimenko, but the European Space Agency still doesn't know if it successfully drilled the comet's surface. They don't even know where it finally came to rest. Meanwhile, its orbiting companion Rosetta is continuing its mission.

Readings from CONSERT, a radar instrument that linked Philae with Rosetta before the lander ran out of power, have narrowed potential landing spots to a 350 metre by 30 metre strip on the comet's head. Scientists at the ESA are now searching images from Rosetta's cameras to see if they can spot Philae, but it is in a region of deep shadow and is only likely to show up when light bounces off its solar panels.

As for Philae's drill, it was one of the last instruments to be activated before the lander switched off. Mission managers know the drill operated as expected, but because the probe was sitting at angle they don't know whether it delivered a sample to the COSAC instrument. This was designed to study molecules from the comet by heating material in an oven and measuring the resulting gas.

Rosetta ramping up
COSAC's data is inconclusive. There may not have been a sample, or the sample may have been too dry, meaning only small amounts of gas were released. "I would have loved to see a clear signal from a clear sample," says COSAC lead Fred Goesmann. "My pessimistic view is we'll never know."




That could be the case even if the ESA can reconnect with Philae, were it to wake up as more sunlight hits its solar panels . The lander's drill has no direct way of confirming it has taken a sample, and there is no camera in the oven the sample was delivered to, even though other lower-temperature ovens on the probe have such cameras. Goesmann says scientists discussed other sensors to confirm a sample during mission planning, but they discarded the idea because of strict weight limits on the lander.

No more data is expected from Philae any time soon, but having delivered the lander, Rosetta is now ramping up its scientific mission. The ESA has placed the spacecraft back into a higher orbit, 30 kilometres above the comet, but it will dip to 20 kilometres on 3 December for 10 days to gather data on the increasing dust and gas spewing from 67P as it nears the sun. The plan is to stay as close to the comet as possible without putting Rosetta at risk from the comet's increasing activity.

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My guess is the Philae will wake up again as the comet get closer to the sun. But because the grappling hooks didnt take as planned, it will get ejected back into space as the comet releases it gases. Since only the comets weak gravity is holding it in place, if that field changes as the comet loses mass, its possible it might "roll over" and become more functional.

Should be some interesting science in the interim.

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My guess is the Philae will wake up again as the comet get closer to the sun. But because the grappling hooks didnt take as planned, it will get ejected back into space as the comet releases it gases. Since only the comets weak gravity is holding it in place, if that field changes as the comet loses mass, its possible it might "roll over" and become more functional.

Should be some interesting science in the interim.

I think that is what they are counting on. The orbiting Rosetta will gather tons of data as the comet slowly dissolves as it nears the sun...

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http://www.newscientist.com/article/mg22429994.700-rosettawatch-comet-water-is-not-like-earths.html

#RosettaWatch: Comet water is not like Earth's
10 December 2014 by Jacob Aron

IF EARTH got its water from space, it probably wasn't delivered by comet. That's according to the latest data from the European Space Agency's Rosetta spacecraft, which has been analysing the water content of comet 67P/Churyumov-Gerasimenko and found it doesn't match the water on Earth.

The question of where Earth got its water – whether from asteroids, comets or in some other way – is a subject of ongoing debate. So analysing comet 67P's water was one of Rosetta's main goals. The spacecraft's ROSINA instrument has been sniffing the vapour around the comet ever since reaching it in August.

Kathrin Altwegg of the University of Bern in Switzerland and her colleagues have now analysed 67P's water, by looking at the amount of deuterium, a heavy isotope of hydrogen, and comparing it with the amount of regular hydrogen (Science, DOI: 10.1126/science.1261952).

"As soon as we got water from the comet, the pattern changed immediately," says Altwegg. The comet's water has around three times as much deuterium as water on Earth, the researchers found. The ratio found on some other comets is much closer to that on Earth, suggesting a link between the icy space rocks and terrestrial water. The different composition of 67P's water suggests a more complex picture.

"We know there is material out there that has the signature of Earth's water in it, but is it the material that supplied it?" says Edwin Bergin of the University of Michigan, Ann Arbor, who previously found that comet Hartley 2 has similar water to that of Earth. Models of asteroid and comet motion within the solar system suggest asteroids were more likely to cross paths with Earth, but we don't yet know if they had the right mix of water to create the oceans. "We need many more measurements of this type to get an understanding of the diversity within the population," Bergin says

"In the end, Earth's oceans are probably a mix of many things," says Altwegg.

The data collected so far may not be the last word on 67P's water. It is possible that there are pockets of water with a different deuterium-to-hydrogen ratio that could be released as the comet nears the sun and heats up. The two halves of the duck-shaped 67P might even have different hydrogen signatures, which would suggest they were once distinct bodies that formed in different parts of the solar system before colliding. "That would be a very interesting result," says Altwegg.

ROSINA's job has been made harder by the loss of Philae, the probe that landed on 67P in November but was unable to survive due to a lack of solar power. That could make signals of heavier molecules, particularly the amino acids necessary for life, more ambiguous.

"The identification of molecules is certainly more difficult," says Altwegg, who had hoped to compare ROSINA's data with Philae's Ptolemy instrument, which was designed to measure molecules in a different way. "If you have two different instruments you can resolve it, and this we cannot do, so it's all on ROSINA more or less."

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Rosetta gets a peek at Comet 67P's "underside"

3 hours ago by Jason Major, Universe Today

A particularly dramatic view of comet 67P/C-G due to the angle of solar illumination, this is a mosaic made from four images acquired by Rosetta's NavCam on January 16, 2015, from a distance of 28.4 km (17.6 miles). The assembled image shows the larger "bottom" lobe of 67P, with a flat region called Imhotep along the left side and, on the lower right, the transition area stretching up to the comet's smaller "head" lobe. Outgassing jets can be seen as faint streaks at the upper right, and ejected dust grains show up as bright specks above its surface.

Read more at: http://phys.org/news/2015-01-rosetta-peek-comet-67p-underside.html#jCp

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http://www.universetoday.com/118901/rosettas-comet-really-blows-up-in-latest-images/

Rosetta's Comet Really "Blows Up" in Latest Images

by Jason Major   on February 9, 2015

First off: no, comet 67P/Churyumov-Gerasimenko is not about to explode or disintegrate. But as it steadily gets nearer to the Sun the comet's jets are getting more and more active and they're putting on quite a show for the orbiting Rosetta spacecraft! Click the image for a jeterrific hi-res version.

The images above were captured by Rosetta's NavCam on Jan. 31 and Feb. 3 from a distance of about 28 km (17 miles). Each is a mosaic of four separate NavCam acquisitions and they have been adjusted and tinted in Photoshop by yours truly to further enhance the jets' visibility. (You can view the original image mosaics and source frames here and here.)

These dramatic views are just a hint at what's in store; 67P's activity will only be increasing in the coming weeks and months and, this weekend, Rosetta will be swooping down for an extreme close pass over its surface!

This Saturday, Feb. 14, Rosetta will be performing a very close pass of the comet's nucleus, soaring over the Imhotep region at an altitude of only 6 km (3.7 miles) at 12:41 UTC. This will allow the spacecraft to closely image the comet's surface, as well as investigate the behavior of its jets and how they interact with its developing coma.

"The upcoming close flyby will allow unique scientific observations, providing us with high-resolution measurements of the surface over a range of wavelengths and giving us the opportunity to sample – taste or sniff – the very innermost parts of the comet's atmosphere," said Rosetta project scientist Matt Taylor.

Read more about Rosetta's Valentine's Day close pass here and watch an animation of how it will be executed below.

https://www.youtube.com/v/dxF2wE24hCI

http://youtu.be/dxF2wE24hCI

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Title 14 February close flyby, 10:15 GMT
Released 16/02/2015 3:00 pm
Copyright ESA/Rosetta/NavCam – CC BY-SA IGO 3.0
Description
Four-image montage of Comet 67P/Churyumov–Gerasimenko comprising images taken on 14 February 2015 during the first dedicated close flyby. This image set was taken at 10:32 GMT from a distance of 12.6 km from the comet centre, or about 10.6 km from the surface seen in the foreground. Using the surface distance, the image scale is 0.9 m/pixel and the montage measures about 1.8 km across.

Closest approach of about 6 km from the comet's surface took place at 12:41 GMT.

The individual images making up this mosaic can be accessed via the blog: CometWatch 14 February – flyby special

Title 14 February close flyby, 19:42 GMT
Released 16/02/2015 3:00 pm
Copyright ESA/Rosetta/NavCam – CC BY-SA IGO 3.0
Description
Four-image montage of Comet 67P/Churyumov–Gerasimenko comprising images taken on 14 February 2015 during the first dedicated close flyby. This set was taken at 19:42 GMT from a distance of 31.6 km from the comet centre. The image scale is 2.7 m/pixel and the montage measures 5.5 km across.

Closest approach of about 6 km from the comet's surface took place at 12:41 GMT.

The individual images making up this mosaic can be accessed via the blog: CometWatch 14 February – flyby special

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http://www.theverge.com/2015/3/11/8189569/philae-lander-waking-first-attempt

Scientists prepare to wake Philae lander from its deep sleep in the shadows of comet 67P
By James Vincent  on March 11, 2015 07:36 am  @jjvincent

Starting tomorrow, scientists from the European Space Agency (ESA) will attempt to make contact with the stricken Philae lander for the first time in nearly four months.

The spacecraft successfully touched down on comet 67P/Churyumov-Gerasimenko in November last year, but an unexpectedly bouncy landing left it stranded in an area far colder and with far less sunlight than scientists had originally planned. The craft was able to carry out a number of experiments over the next three days, but eventually entered a low power state before it ran out of power. Now, as the comet draws closer to the Sun and receives more heat and light, scientists are hopeful it will awaken again in the coming weeks, to finish off the work it started.

"Philae currently receives about twice as much solar energy as it did in November last year," says the lander's project manager Stephan Ulamec. "It will probably still be too cold for the lander to wake up, but it is worth trying. The prospects will improve with each passing day."

For Philae to wake up completely, the interior of the craft must be at least -45ºC and its solar panels must be receiving a minimum of 5.5 watts of power. Once its core systems realize that these criteria have been met, the lander will attempt to charge its battery, switching on its receiver every 30 minutes to listen for instructions from the orbiting Rosetta. Scientists say it's possible that Philae has already woken up, but that the lander doesn't yet have enough power to communicate with Rosetta.

"At this time, we do not yet know that the lander is awake," says Koen Geurts of the Rosetta control center. "To send us an answer, Philae must also turn its transmitter – and that requires additional power."

Between the 11th and 20th of March, Rosetta will make a number of flybys during Philae's daytime — that is, when the side of the comet its on is exposed to sunlight. A day on 67P currently lasts 12.4 hours and scientists believe that Philae is only exposed to the Sun for 1.3 hours every day — not even half of what was planned for. If initial communication is made in the next few weeks, scientists can begin checking on Philae's condition. "We will then evaluate the data," says Geurts. "What is the state of the rechargeable battery? Is everything on the lander still functioning? What is the temperature? How much energy is it receiving?"

Even if this initial attempt at communication doesn't work, ESA scientists are hopeful that they will have more chances in the future as the comet gets closer to the Sun. "If we cannot establish contact with Philae before 20 March, we will make another attempt at the next opportunity," says Ulamec. "Once we can communicate with Philae again, the scientific work can begin."