Author Topic: News of the Comet-hunting Rosetta mission  (Read 9471 times)

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Rick

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Rosetta's Target Comet is Becoming Active (Comet 67P/Churyumov-Gerasimenko)

 The target of ESA’s Rosetta mission has started to reveal its true personality as a comet, its dusty veil clearly developing over the last six weeks.

The sequence of images presented here of comet 67P/Churyumov–Gerasimenko were taken between 27 March and 4 May, as the gap between craft and comet closed from around 5 million km to 2 million km.

By the end of the sequence, the comet’s dusty veil – the ‘coma’ – extends some 1300 km into space. By comparison, the nucleus is roughly only 4 km across, and cannot yet be ‘resolved’.

The coma has developed as a result of the comet moving progressively closer to the Sun along its 6.5 year orbit. Even though it is still more than 600 million km from the Sun – more than four times the distance between Earth and Sun – its surface has already started to warm, causing its surface ices to sublimate and gas to escape from its rock–ice nucleus.

More: http://www.esa.int/Our_Activities/Space_Science/Rosetta/Rosetta_s_target_comet_is_becoming_active

Rick

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Rosetta - The Big Burns Part 3
« Reply #31 on: Jun 19, 2014, 10:14:11 »
Rosetta - The Big Burns Part 3

On Wednesday, 18 June, Rosetta will conduct the third in a series of three ‘Big Burns’, which are themselves part of the ten-burn series of orbit correction manoeuvres (OCMs) that are taking us to arrival at comet 67P/C-G on 6 August.

We’ve dubbed these three the ‘Big Burns’ because, well, they’re big.

The first two, on 21 May and 4 June, used 218 kg and 190 kg of propellant, respectively, and delivered a delta-v (change in velocity) of 289.9 and 269.5 m/s, respectively.

Both delivered results to within just a few percent of the planed delta-v, indicating that, so far, everything is working nominally with the spacecraft’s propulsion system, even though it is working well outside its design range.

“The series of ten OCMs during May to August has to deliver a total of about 775 m/s delta-v, and we’ve already achieved about three-quarters of that,” says Sylvain Lodiot, Rosetta Spacecraft Operations Manager. “We continue monitoring all the OCMs very closely.”

More: http://blogs.esa.int/rosetta/2014/06/17/the-big-burns-part-3/

Rick

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Rosetta's Comet: Expect the Unexpected
« Reply #32 on: Jun 19, 2014, 23:35:42 »
Rosetta's Comet: Expect the Unexpected

 An image snapped earlier this month by ESA’s Rosetta spacecraft shows its target comet has quietened, demonstrating the unpredictable nature of these enigmatic objects.

The picture was captured on 4 June by Rosetta’s scientific camera, and is the most recent full-resolution image from the narrow-angle sensor. It has been used to help fine-tune Rosetta’s navigation towards comet 67P/Churyumov–Gerasimenko, which was 430 000 km away at the time.

Strikingly, there is no longer any sign of the extended dust cloud that was seen developing around nucleus at the end of April and into May, as shown in our last image release. Indeed, monitoring of the comet has shown a significant drop in its brightness since then.

More from ESA.

Rick

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Rosetta's Comet Target 'Releases' Plentiful Water
« Reply #33 on: Jul 01, 2014, 08:34:25 »
Rosetta's Comet Target 'Releases' Plentiful Water

omet 67P/Churyumov-Gerasimenko is releasing the Earthly equivalent of two glasses of water into space every second. The observations were made by the Microwave Instrument for Rosetta Orbiter (MIRO), aboard the European Space Agency's Rosetta spacecraft on June 6, 2014. The detection of water vapor has implications not only for cometary science, but also for mission planning, as the Rosetta team prepares the spacecraft to become the first ever to orbit a comet (planned for August), and the first to deploy a lander to its surface (planned for November 11).

"We always knew we would see water vapor outgassing from the comet, but we were surprised at how early we detected it," said Sam Gulkis, principal investigator of the MIRO instrument at NASA's Jet Propulsion Laboratory in Pasadena, California. "At this production rate, comet 67P/Churyumov-Gerasimenko would fill an Olympic-size swimming pool in about 100 days. But, as the comet gets closer to the sun, the gas production rate will increase. With Rosetta, we have an amazing vantage point to observe these changes up close and learn more about exactly why they happen."

More: http://www.jpl.nasa.gov/news/news.php?release=2014-212

Rick

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Rosetta heads for space 'rubber duck'
« Reply #34 on: Jul 17, 2014, 18:42:11 »
Rosetta heads for space 'rubber duck'

Comet 67P/Churyumov-Gerasimenko is far more irregular in shape than anyone imagined.

It has already been dubbed the "rubber duck" in space.

The latest pictures were acquired by the approaching Rosetta probe from a distance of about 12,000km.

Over the course of the next three weeks, the spacecraft expects to reduce that separation to less than 100km.

More: http://www.bbc.co.uk/news/science-environment-28351234

Rick

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The Dual Personality of Comet 67P/Churyumov-Gerasimenko
« Reply #35 on: Jul 18, 2014, 07:53:09 »
The Dual Personality of Comet 67P/Churyumov-Gerasimenko

This week’s images of comet 67P/Churyumov-Gerasimenko reveal an extraordinarily irregular shape. We had hints of that in last week’s images and in the unscheduled previews that were seen a few days ago, and in that short time it has become clear that this is no ordinary comet. Like its name, it seems that comet 67P/C-G is in two parts.

More: http://blogs.esa.int/rosetta/2014/07/17/the-dual-personality-of-comet-67pc-g/

Rick

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Surface impressions of Rosetta's comet
« Reply #36 on: Jul 24, 2014, 22:53:31 »
Surface impressions of Rosetta's comet

Surface structures are becoming visible in new images of comet 67P/Churyumov-Gerasimenko taken by the scientific imaging system OSIRIS onboard the European Space Agency's Rosetta spacecraft. The resolution of these images is now 330 feet (100 meters) per pixel. One of the most striking features is currently found in the comet's neck region. This part of 67P seems to be brighter than the rest of the nucleus.

As earlier images had already shown, 67P may consist of two parts: a smaller head connected to a larger body. The connecting region, the neck, is proving to be especially intriguing. "The only thing we know for sure at this point is that this neck region appears brighter compared to the head and body of the nucleus," says OSIRIS Principal Investigator Holger Sierks from the Max Planck Institute for Solar System Research in Germany. This collar-like appearance could be caused by differences in material or grain size, or could be a topographical effect.

More: http://www.jpl.nasa.gov/news/news.php?release=2014-243

Rick

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Rosetta's Comet: Imaging the Coma
« Reply #37 on: Aug 01, 2014, 08:37:48 »
Rosetta's Comet: Imaging the Coma

Less than a week before 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.

A new image from July 25, 2014, clearly reveals an extended coma shrouding 67P's nucleus. "Our coma images cover an area of 150 by 150 square kilometers (90 by 90 square miles)," said Luisa Lara from the Institute of Astrophysics in Andalusia, Spain. Most likely these images show only the inner part of the coma, where particle densities are highest. Scientist expect that 67P's full coma actually reaches much farther.

More: http://www.jpl.nasa.gov/news/news.php?release=2014-256

Rick

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Rosetta Takes Comet's Temperature
« Reply #38 on: Aug 02, 2014, 14:57:56 »
Rosetta Takes Comet's Temperature

ESA's Rosetta spacecraft has made its first temperature measurements of its target comet, finding that it is too hot to be covered in ice and must instead have a dark, dusty crust.

The 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.

More: http://sci.esa.int/rosetta/54437-rosetta-takes-comets-temperature/

Rick

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Rosetta arrives at comet 67P/C-G - follow the event live
« Reply #39 on: Aug 06, 2014, 12:53:30 »
Rosetta arrives at comet 67P/C-G - follow the event live

On 6 August, after a decade-long journey through space, ESA’s Rosetta will become the first spacecraft in history to rendezvous with a comet.

Follow the event marking this momentous occasion at ESA's Spacecraft Operations Centre at Darmstadt, Germany.

Programme for the day

The provisional programme can be found here.

Live streaming

The event will be streamed live on http://www.esa.int & http://www.livestream.com/eurospaceagency.

Rick

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Rosetta Arrives!
« Reply #40 on: Aug 06, 2014, 12:56:28 »
Rosetta Arrives!

After a decade-long journey chasing its target, ESA’s Rosetta has today become the first spacecraft to rendezvous with a comet, opening a new chapter in Solar System exploration.

Comet 67P/Churyumov–Gerasimenko and Rosetta now lie 405 million kilometres from Earth, about half way between the orbits of Jupiter and Mars, rushing towards the inner Solar System at nearly 55 000 kilometres per hour.

The comet is in an elliptical 6.5-year orbit that takes it from beyond Jupiter at its furthest point, to between the orbits of Mars and Earth at its closest to the Sun. Rosetta will accompany it for over a year as they swing around the Sun and back out towards Jupiter again.

More: http://www.esa.int/Our_Activities/Space_Science/Rosetta/Rosetta_arrives_at_comet_destination

MarkS

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Re: News of the Comet-hunting Rosetta mission
« Reply #41 on: Aug 06, 2014, 19:51:33 »
Stunning picture of the comet!  I never expected it to be quite like that.  Though I don't know exactly what I was expecting.

Carole

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Re: News of the Comet-hunting Rosetta mission
« Reply #42 on: Aug 06, 2014, 20:07:27 »
Looks like a lump of builders rubble that has fallen in wet concrete, been dug out and left to dry.

Carole

Mike

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Re: News of the Comet-hunting Rosetta mission
« Reply #43 on: Aug 06, 2014, 20:15:54 »
Amazing images and completely different to how I expected a comet to look. I can't wait till the little lander gets dropped.
We live in a society exquisitely dependent on science and technology, in which hardly anyone knows anything about science and technology. Carl Sagan

Canadian Roger

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Re: News of the Comet-hunting Rosetta mission
« Reply #44 on: Aug 06, 2014, 20:26:09 »
I had expected a smoother, almost sand-blasted, surface.

Perhaps when it gets closer, we'll see a surface more like the penitentes I saw above ALMA in Chile.  
http://en.wikipedia.org/wiki/Penitentes#mediaviewer/File:Penitentes_Ice_Formations.png