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Comets

JSON????? That's my day job creeping in... also shows it's never a good idea to post from an iPhone.

But wait! You may have a late booking chance of escape Rynner2. Some bits and bobs might be emerging from the inferno. Looks like i'll have to set the alarm clock Sunday morning after all.

BTW - never mind bright comets, when are we going to get our next milky way supernova? 409 years is taking the Michael.
 
Hope still for 'dead' Comet Ison
By Jonathan Amos, Science correspondent, BBC News

Comet Ison, or some part of it, may have survived its encounter with the Sun, say scientists.
The giant ball of ice and dust was initially declared dead when it failed to re-emerge from behind the star with the expected brightness.
All that could be seen was a dull smudge in telescope images - its nucleus and tail assumed destroyed.

But recent pictures have indicated a brightening of what may be a small fragment of the comet.
Astronomers admit to being surprised and delighted, but now caution that anything could happen in the coming hours and days.
This remnant of Ison could continue to brighten, or it could simply fizzle out altogether.

Karl Banttam wrote on the Nasa Comet Ison Observing Campaign blog: "It does appear that a least some small fraction of Ison has remained in one piece and is actively releasing material.
"We have no idea how big this nucleus is, if there is indeed one. If there is a nucleus, it is still too soon to tell how long it will survive.
"If it does survive for more than a few days, it is too soon to tell if the comet will be visible in the night sky."

The European Space Agency, too, which had been among the first organisations to call the death of Ison, has had to re-assess the situation. A small part of the nucleus may be intact, its experts say.

How much of the once 2km-wide hunk of dirty ice could have survived is impossible to say.
Passing just 1.2 million km above the surface of the Sun would have severely disrupted Ison. Its ices would have vaporized rapidly in temperatures over 2,000C. And the immense gravity of the star would also have pulled and squeezed on the object as it tumbled end over end.

Whatever happens next, comets are going to be a big feature in the news over the next year.
In 11 months' time, Comet Siding Spring will breeze past Mars at a distance of little more than 100,000km. And then in November 2014, the European Space Agency's Rosetta mission will attempt to place a probe on the nucleus of Comet 67P/Churyumov-Gerasimenko.

http://www.bbc.co.uk/news/science-environment-25143861

Further disruption of Ison is much less likely now, as it speeds away from the danger zone. Fingers crossed! 8)
 
For the latest news, perhaps:

The Sky at Night
BBC1 South West
Comet Chasing
Today on BBC1 South West from 11:45pm to 12:05am

Astronomers always get excited about comets and in December they are looking forward to something rather special. The snappily named Comet C/2012 S1 ISON has travelled from the very edges of our solar system on a one way ticket around the sun. As it heats up there is intense speculation about whether it will develop a beautiful tail or just break apart. On the Canary island of La Palma the team use both the Liverpool and Issac Newton telescopes to go comet chasing.
 
What made them name it after a dodgy fictional antique dealer?
 
Hibernating spacecraft Rosetta to awaken for comet chase
At 10am on Monday morning the spacecraft Rosetta will wake up from its deep space slumber and power-up so it can begin chasing a comet and fulfill its 10 year mission to land a probe on its surface.
By Sarah Knapton, Science Correspondent
7:00AM GMT 19 Jan 2014

It has been sleeping quietly in space for more than two and a half years.
But at 10am tomorrow an internal alarm will awaken the Rosetta spaceship, allowing scientists to begin one of the most technologically advanced missions ever attempted.
Put simply researchers are trying to catch a comet.

Over the next few months Rosetta will chase down 67P/Churyumov-Gerasimenko before harpooning the frozen ball of dirty ice and attempting to make a soft landing on its surface.

“It will be an amazing achievement for human endeavour, an 'Armageddon’ type thing,” said project scientist Matt Taylor at the European Space Agency, referring to the Bruce Willis film in which Willis lands on an asteroid to save the world from imminent destruction.
“We’re not just landing on the Moon, we’re dealing with something dynamic, which is kicking off tonnes of dust and gas every minute.”

The comet is currently hurtling through space at 24,600 miles per hour and its nucleus is only 2.5 miles wide.
Scientists compare the task to a fly trying to land on a speeding bullet. It is the stuff of science fiction, but it’s - hopefully - about to become science fact.

Comets are the primitive building blocks of the Solar System, left over from a planet-building time when our Sun was just a disc of spinning dust and gas.
Made of ice, dust and small rocky particles, it is likely they delivered the first water to Earth and may have even seeded the planet with the building blocks for life.
Cometary dust brought back to Earth by NASA’s stardust mission contained glycine, an amino acid that is a basic part of our DNA.

“We look at comets as being a time capsule, they are relics from the beginning of the solar system,” said Taylor, “We felt we had to go to one.”

Rosetta has already been travelling for more than a decade after the craft was launched on March 2 2004, from Kourou, French Guiana.
But the comet is moving far faster than speeds which could ever be achieved by a space ship leaving Earth. So the craft has spent the time since, using the gravitational pull of the Earth and Mars to act as a sling shot and allow it to pick up acceleration.

When it reached the crucial speed in July 2011 the spacecraft was put into deep-space hibernation for the coldest, most distant leg of the journey as it travelled some 497 million miles from the Sun, close to the orbit of Jupiter as the comet headed into outer Solar System.
Scientists extended its solar arms to catch the Sun’s rays and placed in a slow spin to maintain stability. The only devices left running were its computer and several heaters.

Thirty-one months on, Rosetta’s orbit has brought it back to within 418 million miles of the Sun, and there is finally enough solar energy to power the spacecraft fully again.

Now Rosetta’s internal alarm clock is set to rouse the sleeping space craft at 10am tomorrow so that it is ready to catch the comet when it returns to the inner solar system. There are also three back up alarm clocks, should the spaceship choose to hit the snooze button. ;)

Once the 6,600 lbs craft wakes up, it will first warm up its navigation instruments before spinning around to point its main antenna at Earth, to let the ground team know it is still functioning.
Scientists are likely to face an eight hour wait before the first vital signs are beamed back to earth.

Because of Rosetta’s distance – just over 501 million miles from Earth – it will take 45 minutes for the signal to reach the ground stations. The first opportunity for receiving a signal on Earth is expected between 5.30pm and 6.30pm tomorrow.

Fred Jansen, ESA’s Rosetta mission manager, said: “We’re very excited to have this important milestone in sight, but we’ll be anxious to assess the health of the spacecraft after Rosetta has spent nearly 10 years in space.”

Mr Taylor said: “It’s sort of similar to putting the TV on standby for three years and expecting it come back on when you pressed the remote.”

After wake-up, Rosetta will still be about 5.6 million miles from the comet. But by May it will just 1.2 million miles from its target and scientists expect to be able to make final calculations about the comet’s position and orbit.

After extensive mapping of the comet’s surface during August and September, a landing site for the mission’s 220 lbs Philae probe will be chosen.
“One of the main problems is how we are going to stick to the comet. It has a weak gravitational field, so as it touches down harpoons will fire to keep the lander in position,” said Mr Taylor.

Philae, is around 35 cubic feet in size and is named after an island on the river Nile, where an obelisk was found containing an inscription which played an important role in deciphering the hieroglyphics on the Rosetta stone.

The lander will send back a panorama of its surroundings and high-resolution pictures of the surface and will perform analysis of the composition of the ices and organic material.

A drill will take samples from 8-11 inches below the surface, feeding them to Philae’s laboratory for analysis. Rosetta will then stay alongside the comet as it moves closer to the Sun.
Instruments on board will analyse the gases of the tail; probe the comets interior; measure dust grains and study its atmosphere and gravity.

The comet will reach its closest distance to the Sun on 13 August 2015 at about 115 million miles, roughly between the orbits of Earth and Mars. Even if the lander is still on the comet by then its instruments will have been rendered useless due to the heat of the Sun.

The £1 billion project will see Rosetta follow the comet throughout the remainder of 2015, as it heads away from the Sun and activity begins to subside.
“This will give us a unique insight into how a comet 'works’ and ultimately help us to decipher the role of comets in the formation of the Solar System,” added Mr Taylor.
“We used to look at the moon and then we went there. We saw comets and now we will have gone there.”

http://www.telegraph.co.uk/science/spac ... chase.html

Various diagrams on page.
 
Rosetta comet-chaser phones home
By Jonathan Amos, Science correspondent, BBC News, Darmstadt

[Video: Delight in the control room as Rosetta sends back a signal confirming it is "awake"]

Rosetta, Europe's comet-chasing spacecraft, has woken from its slumber.
A signal confirming its alert status was received by controllers in Darmstadt, Germany, at 18:17 GMT.

Rosetta has spent the past 31 months in hibernation to conserve power as it arced beyond the orbit of Jupiter on a path that should take it to Comet 67P/Churyumov-Gerasimenko in August.
Engineers will now finesse the probe's trajectory and prepare its instruments for the daring encounter.
One of the highlights of the mission will be the attempt to put a small robotic lander, Philae, on the surface of the 4.5km-wide comet. This will occur in November.

There were nail-biting moments in the Darmstadt control room as scientists waited for the signal to come through. Three quarters of the way through the hour-long window of opportunity, they got what they were waiting for.
Gerhard Schwehm, mission manager for Rosetta, said: "After 31 months in hibernation, what is 45 minutes to wait?"
Andrea Accomazzo, the spacecraft operations manager, said: "I think it was the longest hour of my life, but also one of the most rewarding."

Monday's message, when it arrived, was a simple one - just a spike on the screens here at the European Space Agency's operations centre.
It was picked up in California by a 70m dish belonging to the US space agency, and then routed to Germany.
The signal contained no spacecraft telemetry, but its mere receipt from 800 million km away confirmed to controllers that Rosetta's automated systems were operating as expected.
In the coming hours and days, the Darmstadt team will talk to Rosetta to establish the full status of its systems.

It will be a slow process. The huge distances between the probe and Earth mean telecommands have a one-way travel time of 45 minutes.

Rosetta was put into hibernation in June 2011 because its trajectory through the Solar System was about to take it so far from the Sun that its solar panels would harvest minimal energy. The decision was therefore taken to put the spacecraft in a deep sleep.

Now that it is arcing back towards the Sun, more power is becoming available to operate the probe.
"From now until mid-March, we have planned virtually no activities on the spacecraft. We can afford to run only some basic check-outs," explained Andrea Accomazzo.
"But from mid-March to the end of April, we will be switching on the instruments one by one. We'll check them out and in a few cases even update their software."

From May, Rosetta will begin firing its thrusters to begin zeroing in on Comet 67P. Today, the separation is nine million km away. By mid-September, it will have been reduced to just 10km.

Launched back in 2004, Rosetta has taken a rather circuitous route out to its target.
This has involved making a number of flybys of the inner planets, using their gravity to pick up sufficient speed for the eventual encounter.
It has already delivered some fascinating science, particularly from the close passes it made to two asteroids - the rocks Steins, in 2008, and Lutetia, in 2010.

The plan is for Rosetta to escort the comet as it moves closer towards the Sun, monitoring the changes that take place on the body. The Philae lander will report changes that occur at the surface.

Comets - giant "dirty snowballs", as some have called them - are believed to contain materials that have remained largely unchanged since the formation of the Solar System 4.6bn years ago.
Rosetta's data should act therefore as a kind of time machine, to enable researchers to study how our local space environment has changed over time.

"We will sample the physical and chemical composition of the comet," said Matt Taylor, Esa's Rosetta project scientist.
"This will give us knowledge on how and where the comet was formed, and about its subsequent journey through the evolution of the Solar System.

"We can connect that as well to the formation of the planets themselves. And, in addition, the elemental make-up of the comet can be considered 'star stuff' - it will provide us knowledge of the formation processes with the Sun itself."

Rosetta is being billed as the big space event of 2014, and it is clear from the general and social media reaction to Monday's wake-up that interest in the mission is considerable.
"Science in general catches the public's imagination," said Thomas Reiter, Esa's director of human spaceflight and operations.
"In general, we try to find answers to fundamental questions, such as where do we come from, what will be our destiny and will we have to stick to this planet?
"The knowledge we get from missions like Rosetta - which is now moving into a very interesting stage - gets us closer to answering those types of questions."

http://www.bbc.co.uk/news/science-environment-25814454
 
Rosetta comet-chaser initiates 'big burn'
By Jonathan Amos, Science correspondent, BBC News

Europe's Rosetta spacecraft is in the midst of another critical moment in its mission to rendezvous with a comet.
The satellite has lit its thrusters for a near-eight-hour burn that should put it on just the right path to meet up with 67P/C-G in August.
Although eight further manoeuvres will be required to complete the task, Wednesday's is the big one.

Rosetta, which was launched from Earth 10 years ago, plans to orbit the comet and put a small lander on its surface.
If all goes well, the mission should return some remarkable insights on the behaviour and chemical make-up of its icy quarry.

Rosetta's automated systems initiated the thruster firing at 15:23 GMT (16:23 BST; 17:23 CEST).
Engineers at the European Space Agency's (Esa) "mission control" in Darmstadt, Germany, received confirmation some 28 minutes later.
The delay was down to the time it takes for signals to travel 500 million km - the current distance between Rosetta and Earth.

"#BigBurn has started! #Rosetta team at ESOC seeing good telemetry," the control room's Twitter feed reported.
"@ESA_Rosetta mission control seeing thruster temperatures rise as they heat up, 500mln km away #BigBurn," it added.

Comet 67P/C-G is travelling around the Sun on a big loop that takes it out beyond the orbit of Jupiter and then back in to just inside the orbit of Mars.
Rosetta is attempting to target its rendezvous at the start of the inward curve, before our star can warm the 4km-wide body and trigger large jets of gas and dust from its surface.

At the moment, the separation between the pair is about one million km, and closing.
Wednesday's burn is designed to slow Rosetta's velocity relative to the comet and thus keep it on a trajectory to arrive just in front of the object in 11 weeks' time.
The idea by then is to have reduced the relative velocity from the present 755m/s down to just 1m/s, with a separation under 200km.

Relative to the Sun, of course, their speed will not be "walking pace" - rather, the duo will be hurtling through space at more than 13km/s as they fall deeper and deeper into our star's gravity well.

Even though engineers conducted a small test burn two weeks ago, there was a little nervousness at the European Space Operations Centre ahead of Wednesday's manoeuvre.
That was because Rosetta has a leak in the system it uses to pressurise its propulsion tanks.
Pressurising the propellant ensures there is a steady, even flow of fluid into the combustion chambers of the thrusters.

This leak has been known about for some years, and engineers believe they understand it and can work around it.
But if a problem is to show itself, it could well be during the big burn.
"Operating at a lower pressure leads to less efficient combustion, and that means using more propellant. But this is OK because thanks to our good and accurate navigation, we have more than enough reserve to cope with this," explained Andrea Accomazzo, Esa's Rosetta Spacecraft Operations Manager (SOM).

"What is really more of a risk is that at low pressure the thrusters can operate more like they're sneezing than burning. It could make the combustion very rough - very variable."

The SOM and his team will be watching the telemetry from Rosetta very carefully to assess the stability of the four 10-newton thrusters being used during Wednesday's firing sequence.

Following the burn, scientists will take new pictures of the comet with Rosetta's Osiris camera.
These images will help gauge better the comet's exact position on the sky so that the next, slightly smaller burn, planned for 4 June, can be executed properly.

http://www.bbc.co.uk/news/science-environment-27498534
 
Rosetta: Icy quarry coming into view

Take your seats because the show is about to begin.

The European Space Agency's Rosetta probe is edging ever closer to the Comet 67P/Churyumov-Gerasimenko for what is expected to be one of the most daring space encounters in history.
Wednesday saw the satellite successfully complete the fourth of its 10 planned thruster manoeuvres.
These are designed to get the mission into orbit around the 4km-wide comet on 6 August.

Today (Thursday), the separation between Rosetta and its icy quarry is about 165,000km.
"We're now less than half the Earth-Moon distance. That's how close we are now," explained Prof Holger Sierks, who leads the Osiris camera team on Rosetta.
"I think anybody on the street will understand that - it's actually really close-by in space."

The picture at the top of this page is the first of what will be a regular release now from Prof Sierks and his team at the Max Planck Institute for Solar System Research, in Göttingen, Germany.
The comet may not be much to look at just yet - it is now barely a pixel across - but it will simply get bigger and bigger.
One of the key jobs the Osiris camera system has right now is to eyeball the comet to assist with navigation.
But, of course, it's also a very important science instrument.

Not only will Osiris map the object and its surface features, but it carries a number of filters to elicit information about chemical composition.

Imaging is being supported by big ground-based telescopes.
Interesting observations already emerging relate to the activity of the comet.
A few weeks back, it was seen to be throwing out quite a bit of material - gas and dust. Not anymore.
"The comet, after a short time of activity, is back at rest," says Prof Sierks. "So, the message I guess is expect the unexpected."

As the comet moves closer to the Sun, it will get significantly more active, and Osiris will have to take care to protect the optics on its wide and narrow-angle cameras.
It has a set of doors that will open only when images are being acquired.
"This is a must do," says Prof Sierks. "It's essential because we want to preserve the quality of our mirrors, which are directly exposed to the dust flow.
"The system is set out and qualified for many, many door cycles. We open the door and shoot, shoot, shoot - and then close the door.

"In normal circumstances, such as on our camera on [Nasa's asteroid mission] Dawn, we are qualified for 400 cycles. In the environment around an asteroid, you can open the door and leave it open.

"But with Rosetta, we are qualified for 10,000 door cycles. We could be opening and closing the door maybe 10 or 20 times a day. So we open an eye, look quickly for what we want, and then close the eye."
The next image release is likely to occur on 3 July. By then, 67P will be about six pixels across.

Osiris' early tasks will be to find a suitable location for Rosetta to put down its Philae lander.
It will start by making a global map at a resolution of about 20m. A site selection process will then narrow to a choice of two landing zones (first choice and back-up), which will be imaged at roughly 50cm resolution.

By moving in very close itself, Rosetta can get much more detailed pictures, but the error on the landing is going to be on the order of 100m so tracing every bump and dip on the comet is just not necessary.

Philae's landing is still projected for early November.

I learnt this week that the main probe may also end its days by being dropped on to the surface of 67P, in much the same way as the Near-Shoemaker spacecraft was intentionally ditched on Asteroid 433 Eros in 2001. But that is a way down the road; first, let's just get to the comet.

http://www.bbc.co.uk/news/science-environment-27926614
 
Rosetta's target is 'double' comet
By Jonathan Amos, Science correspondent, BBC News

Europe's Rosetta probe has acquired some sensational new images of the comet it is chasing through space.
The pictures show that 67P/Churyumov-Gerasimenko appears to be not one but two objects joined together. It is what scientists call a "contact binary".
How the comet came to take this form is unknown.

It is possible that 67P suffered a major fracture at some point in its past; it is also possible the two parts have totally different origins.
What is clear is that the European Space Agency (Esa) mission team now has additional and unexpected considerations as it plans how to land on the comet later this year - not least, which part of the comet should be chosen for a touchdown?

The images in the sequence of nine were acquired last Friday.
They are an interpolation. That is, the "real" pictures are much more pixelated because of the thousands of km that still separate the probe and the comet. The outlines that you see have therefore been "smoothed" to make the scene easier to understand.

Rosetta's Osiris Narrow Angle Camera has a whole series of images that can be run together as a movie. This is expected to be released later this week.
With hindsight, there were indications in last week's official image release that something unusual might be about to unfold. But the idea that 67P could be a contact binary is a major surprise.

Rosetta is still refining its rendezvous with the comet, firing its thrusters weekly to bring itself into orbit on 6 August.
By that stage, the Esa probe should be no more than 70km from the surface of the 4.5km-wide ball of ice.
Once scientists understand better the gravitational field of 67P, the orbit will be lowered to about 30km.

It is at that point that mapping can begin to select a touchdown zone for Philae - the small landing robot currently riding piggyback on Rosetta.
This historic touchdown is currently scheduled for 11 November.

----------------------------------------

67P/Churyumov-Gerasimenko
Named after its 1969 discoverers Klim Churyumov and Svetlana Gerasimenko
Referred to as a "Jupiter class" comet that takes 6.45 years to orbit the Sun
Orbit takes it as close as 180 million km from the Sun, and as far as 840 million km
The icy core, or nucleus, is about 4km (2.5 mi) across and rotates every 12.4 hours

http://www.bbc.co.uk/news/science-environment-27110882
 
What weird shapes, I tend to think of comets and asteroids as sort of potato shaped, the smaller one is but the larger looks square and flattish.
 
Several detailed images of the surface here:

Rosetta mission: Potential comet landing sites chosen
By Jonathan Amos, Science correspondent, BBC News

Europe's Rosetta mission, which aims to put a robot on Comet 67P/Churyumov-Gerasimenko, has identified five potential locations for the touchdown.
The choice of sites was driven largely by operational considerations - they are places engineers believe a lander can get down with the least risk.
No-one has attempted to land on a 10-billion-tonne comet before.

The Rosetta probe will despatch its Philae contact robot to 67P's icy surface on 11 November.
The European Space Agency says it will be a one-shot opportunity.

Rosetta and the comet are currently about 400 million km from Earth, making real-time radio control impossible.
Instead, the process will have to be fully automated with commands uploaded several days in advance.

The five sites on the "longlist" were selected at the end of a special meeting convened in Toulouse, France, this past weekend.
Esa project managers were joined by attendees from the space agencies of France (Cnes) and Germany (DLR), which play key roles in the Philae effort.
Instrument principal investigators on the washing machine-sized robot were also there to argue their preferences, as were the engineers, who could explain the technical possibilities.

If one considers the comet to look like a rubber duck, then three of the chosen potentials (B, I and J) are on the head. Two are on the body (A and C). The dramatic neck region has been ruled out.
The letter designation stems from an even longer list of 10 that was used to kick-off the whole selection process. The letter ordering carries no weight.
A landing site needs to be relatively flat and free from boulders and fissures.

One key requirement has been the need to find places on the comet that experience something of a day/night cycle.
This will give not only a better appreciation of the changing behaviour of 67P under all conditions, but will provide the lander with some important protection - from too much sun, which could lead to overheating, or too little light, which would make it difficult to charge the batteries.

The engineers have also emphasised the need to find locations where Rosetta can deliver Philae at the right altitude and velocity, and maintain a communications link throughout the descent, which is likely to take several hours.

The longlist will be reduced to a leading candidate and perhaps a couple of back-ups in mid-September.
A final go/no-go decision on a target landing site is expected by mid-October.
By then, Rosetta's cameras and other instruments will have returned detailed data on the number one choice.

Comet 67P has very little gravitational attraction - several hundred thousand times weaker than what Philae would experience at the Earth's surface.
For this reason, it will touch down at no more than a walking pace - about 1m/s.
It will use harpoons and ice screws to try to hang on to the comet and avoid bouncing back into space. :wince:

http://www.bbc.co.uk/news/science-environment-28923010
 
Rosetta set for 'capture' manoeuvres
By Jonathan Amos, Science correspondent, BBC News

The Rosetta probe is about to begin the manoeuvres that will place it properly into orbit around Comet 67P/Churyumov-Gerasimenko.
The European spacecraft is currently flying arcs over the "ice mountain" that take it no closer than 52km.

But from Wednesday, Rosetta will gradually drop this distance so that come next week it will be at an altitude of just 29km.
At that point, 67P's gravity should capture the spacecraft.

European Space Agency (Esa) flight director Andrea Accomazzo said: "The first orbit - we will actually fly only half of it for seven days, and then we'll change the orbital plane and fly for another seven days.
"And then, if the comet environment allows us to continue, we'll go further down, first to 19km and then to 10km from the centre of the comet."

Scientists and engineers on the mission are busy trying to determine the best place to land on 67P.
They have put together a longlist of five sites on the 4km-wide object and need to reduce this to two - a primary and a back-up - by 15 September, when Esa expects to announce the preferences at a media conference in Paris.

The landing itself - which will be performed by Rosetta's contact robot Philae - is scheduled to take place on 11 November.

Accomazzo said mission controllers had "some headaches" in trying to work out precisely where the centre of mass is on the 10-billion-tonne, rubber-duck-shaped comet.
It is an important detail for designing a safe orbit, but the flight director expressed confidence that this issue would be resolved in the coming days.

At the moment, the comet remains quiet, with very little gas and dust streaming from its surface.
This could change at any time, however, and Accomazzo's team is ready to modify Rosetta's manoeuvres if 67P suddenly comes to life.

Meanwhile, an intense schedule of work is about to get underway to prepare Philae for its historic landing attempt.
Riding piggyback on Rosetta, the little robot has been largely a passive passenger so far.
But it will be switched on again this week to check its sub-systems for the final time.
This will involve cycling its battery and running the rule over its communications equipment.

The German space agency (DLR) team looking after Philae will also command the robot to take a picture with its own camera system.
This is something Philae has done in the past. In 2007, it famously snapped an image of Mars as Rosetta flew by the Red Planet.
This time, Philae hopes to set eyes on 67P.

"Obviously, we will not have a nice high-resolution picture as from [Rosetta's Osiris science cameras] and Navcam, but it will be interesting for us to have such a picture," said Barbara Cozzoni, a DLR operations engineer.

Rosetta scientists will be heading to Lisbon, Portugal, next week to present their early impressions of the comet to their peers.
A special session for the mission has been convened at the European Planetary Science Conference.
One issue they must settle very soon is a naming scheme for all the features on the comet's surface.
The words "Rosetta" and "Philae" recall key discoveries made in the study of ancient Egypt.

Fred Jansen, Esa's Rosetta mission manager, said the huge array of craters, cliffs, plains and boulders that populate 67P's surface could soon sport a very similar nomenclature.
"We do not have a fully agreed naming scheme yet, and we are actually late with this because there are plenty of features we can see and resolve," he told BBC News.

"I think we will go in a direction that will not surprise anybody, given Rosetta and Philae as names, and look to some sort of Egyptian theme for naming the different sites."

http://www.bbc.co.uk/news/science-environment-29036303
 
Rosetta takes 'selfie' ahead of landing site selection
By Pallab Ghosh, Science correspondent, BBC News

The Rosetta spacecraft has sent a hauntingly beautiful picture of itself from deep space.
It was taken with the CIVA camera situated on Rosetta's landing craft known as Philae.
The image was taken on 7 September from a distance of about 50km from the comet seen at the top of the picture.

It shows the edge of the spacecraft and one of its 14m-long solar wings glistening in sunlight against the blackness of space.
Faint details of the spacecraft's protective blanket, the ridges of one of the solar wing's supports can be seen clearly as can the wiring and hinges on the wing itself.

At the top of the picture is Comet 67P also known as Churyumov-Gerasimenko with each of its distinct lobes visible.
Five possible landing sites were chosen last month. They were selected because they appeared to be relatively flat and smooth. But as the spacecraft has neared the comet, its rocky jagged surface which can be clearly seen in this picture has come sharply into focus.

More detailed images show that the potential landing sites are less lander-friendly than had first seemed.
To varying degrees they are strewn with boulders, sloping and have perilous cracks which may turn the Philae lander over as it touches down on the surface in November.

The Rosetta team will spend this weekend studying the latest pictures of the potential landing sites in order to pick out what may turn out to be the least worst option.

http://www.bbc.co.uk/news/science-environment-29044139
 
[Big Video]

Rosetta: Decision due on comet landing site

The European Space Agency is about to release more details of its audacious bid to try to land on a comet.
Since early August, its Rosetta probe has been in close proximity to 67P/C-G - a 10-billion-tonne mass of ice and dust some 400 million km from Earth.

Engineers and scientists have spent the weekend debating where on the surface it might be possible to put down a small contact robot.
Esa is expected to announce its primary and reserve choices on Monday.

http://www.bbc.co.uk/news/science-environment-29201988
 
And once again it looks like a bloody quarry.

All those old episodes of Blake's 7 and Doctor Who must have mucked up the space time continuum.
 
It speaks of age. Deep age. Perhaps our deepest genetic heritage...

I am quite awestruck.
 
After 4 hours of gazing at the image, I'm convinced that the figure in the foreground is a God disguised as a mountain. It is now my desktop.
 
God is my desktop..

Mohab is my washpot...

:madeyes:
 
A month and a half to bounce, splat, or landing...

Rosetta: Date fixed for historic comet landing attempt
Jonathan Amos, science correspondent

The date has been fixed for Europe's daring attempt to land on a comet: Wednesday 12 November.

It will see the Rosetta satellite, which is currently orbiting the huge "ice mountain" known as 67P, drop a small robot from a height of 20km.
If all goes well, the lander will free-fall towards the comet, making contact with the surface somewhere in a 1km-wide zone at roughly 15:35 GMT.

The European Space Agency (Esa) says the challenges ahead are immense.
Imagine pushing a washing machine out the back of an airliner at twice cruising altitude and expecting it to hit Regent's Park in London - all while the ground is moving underneath.

Although not really analogous for many reasons, this scenario does give a sense of the difficulties involved. The chances of failure are high. 8)

Esa's confirmed date is actually a day later than the one that had been discussed in provisional planning in recent months.
The extra time will give flight controllers a bit more latitude as they try to get Rosetta into just the right position to deliver the 100kg lander, which goes by the name of Philae.

This requires careful "phasing" of Rosetta's path around 4km-wide 67P so that the satellite turns up at the precise, pre-determined ejection point, 22.5km from the centre of the comet at 08:35 GMT.

Because the whole event will be taking place 509 million km from Earth, any radio signal will take 28 minutes and 20 seconds to reach Esa's ground station network.
It means confirmation of success or failure will not come until perhaps just after 16:00 GMT.

The chosen landing site is on the "head" of the rubber-duck-shaped comet and is currently referred to simply as "J", the designation it was given in a list of possible destinations in the selection process.

It is far from ideal. It contains some terrifying cliffs, but is the flattest, most boulder-free location the mission team could find in its survey of the icy object.
Mapping of J and a back-up site known as "C" is ongoing.

This past week, Rosetta manoeuvred into an orbit just 20km from 67P, enabling its camera system to see details that can be measured on the sub-metre scale.
For landing, such information only has a certain usefulness, however, as the automated touchdown can only be targeted with a best precision that will likely run to hundreds of metres.
And that error is larger than any of the apparently smooth terrains in the J zone. :shock:

The whole separation, descent and landing (SDL) procedure is expected to take seven hours.
Philae will take a picture of Rosetta as it leaves its "parent".

It will also point a camera downwards so that it can see the approaching comet. Not that this information can change anything; Philae has no thrusters to control or alter its descent trajectory. It will land where it will land.

But the images will help controllers determine where the robot ended up after the event.
If Philae gets down successfully into a stable, operable configuration, it will fire harpoons and deploy screws to try to hang on to the surface.
The action of these devices will tell Esa mission control in Darmstadt, Germany, that the surface was engaged.

Will it hang on? Part of the problem here is that no-one really knows what the surface conditions will be.
Philae could sink into a soft powder or impact ice as hard as rock. A major worry is that it could simply bounce off into space.
Whatever the outcome, the Rosetta mission will continue.

Already the main satellite has returned some astonishing pictures of Comet 67P and the close-quarters observations it will conduct over the next year will transform our understanding of these remarkable objects.

http://www.bbc.co.uk/news/science-environment-29380448

I wonder what odds the bookies are giving on a succesful landing? ;)
 
edit: linked the wrong webpage and then I closed my link to an image of Rosetta venting gas from September 12th and now can't find it. Sorry. Here instead is a series of images taken of Rosetta and other comets: http://www.slate.com/blogs/bad_astronomy/2014/08/07/rosetta_gallery_top_ten_photos_so_far.html


The wrongly linked image is of three moons of Saturn, which is pretty cool anyway, so ...
https://cosmosmagazine.squarespace.com/blog/2014/9/23/three-moons-of-saturn-in-cassinis-latest-image

I'm watching a doco on the Chelyabinsk event. Apparently we are rained with about 100 tons of meteoric debris every 24hrs, most of it as fried dust.
 
skinny said:
edit: linked the wrong webpage and then I closed my link to an image of Rosetta venting gas from September 12th and now can't find it. Sorry.
Click to expand...
I had a look and found this:

New Mosaic Reveals Jets Blasting from Rosetta’s Comet
Posted on September 8, 2014

Hidden among the four new images of Comet 67P/Churyumov-Gerasimenko released by ESA this week are a pair of dusty jets shooting from the nucleus of Comet Churyumov-Gerasimenko. The photos were taken September 2, 2014 and posted as a mosaic of four separate images. Bob King from Universe Today re-assembled the four, and added some additional contrast to better show the dual geyser of ice crystals mixed with dust venting from the nucleus.

An earlier Rosetta photo taken of Comet 67P/ Churyumov-Gerasimenko from a great distance and deliberately overexposed showed jets of dust-laden vapor shooting from the comet, but this is the first image I’m aware of that shows both the comet’s surface and its much fainter exhalations.

Jets or sprays of vaporizing ice are what gives a comet its lively appearance. Dust released with water vapor is ultimately pushed back by the pressure of sunlight to grow 67P/C-G’s dust tail. Ultraviolet light from the sun causes volatiles within the vapor to fluoresce a pale blue, creating a second ion or gas tail. The coma or comet atmosphere is a mix of both.

We can expect the jets to grow stronger and hopefully more numerous as 67P/C-G approaches perihelion in August 2015. Because the spacecraft is maneuvering into orbit between the comet and sun, we don’t get the best view of jetting activity. The comet nucleus, illuminated by sunlight, drowns out the fainter jets. Rosetta will make an excursion to the nightside on September 24. Assuming the jets remain active, we might see them backlit by the sun as bright beams extending from the darkened nucleus into space.

http://www.technology.org/2014/09/08/ne ... tas-comet/
 
Rosetta mission: Philae comet lander pictures its target

By Jonathan Amos, Science correspondent, BBC News

The Philae robot, soon to try to land on Comet 67P, has taken another dramatic image of its quarry.

The picture is very similar to the one it acquired in mid-September - only this one is much closer, snapped from a distance of just 16km.
Also new in this picture is 67P's activity. Jets of gas and dust can be seen streaming away from the "neck" region of the rubber duck-shaped comet.

Philae is due to make its historic landing attempt on 12 November.
It is currently riding piggyback on its "mothership", the Rosetta probe.
You can just see the corner of this spacecraft on the left of the image, with one of its 14m-long solar wings dominating the foreground.

The plan is for Rosetta to eject Philae towards 67P just after 0830 GMT on the 12th.
The small gravitational tug from the 4km-wide comet should be enough to pull the robot on to its surface in a descent that is likely to take about seven hours to complete.
If the lander survives this fall, it will be a first. Never before in the history of space exploration has a soft touchdown been made on one of these "ice mountains".

[Video: David Shukman takes a close-up look at the Philae lander]

The new "selfie" released by the European Space Agency is actually a composite of two images taken in quick succession but with different exposure times.
This allowed the very different contrast conditions to be balanced across the entire vista.
Philae acquired the frames on 7 October. It will be the last view from the robot's CIVA camera system until just after separation from Rosetta.
The plan is for Philae to grab a "goodbye" shot of Rosetta as the pair start to recede from each other.

Assuming the landing succeeds, CIVA will then take a full 360-degree panorama of its touchdown location.
This is a relatively flat terrain on the "head" of the duck, currently dubbed "Site J" after its position in a list of possible destinations in the site selection process.

Mission planners were due to meet on Tuesday to give a final confirmation to the J target. This ought to have been a formality.
The big caveat is if Rosetta has seen a "showstopper" in its recent close-in mapping campaign. This would have to be an extremely dangerous surface feature that had gone unrecognised in previous, lower-resolution imaging.
If a no-go situation has been indentified, planners would then move their attention to a back-up landing target on the "body" of the duck called "Site C".

Rosetta, Philae and Comet 67P are currently moving through space some 480 million km from Earth.

...

http://www.bbc.co.uk/news/science-environment-29620127
 
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