Deep Impact/EPOXI

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EarthlingX

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http://www.jpl.nasa.gov : Flight of the Comet
November 05, 2010


This video clip of the flyby is comprised of 40 frames taken from the spacecraft's Medium-Resolution Instrument during the encounter. Image credit: NASA/JPL-Caltech/UMD/Brown University

This video clip was compiled from images taken by NASA's EPOXI mission spacecraft during its flyby of comet Hartley 2 on Nov. 4, 2010. During the encounter, the spacecraft and comet whisked past each other at a speed of 12.3 kilometers per second (27,560 miles per hour). The spacecraft came within about 700 kilometers (435 miles) of the comet's nucleus at the time of closest approach.

"While future generations should have the opportunity to truly explore comets, this flyby gives us an excellent preview of what they will get to enjoy," said EPOXI principal investigator Michael A'Hearn of the University of Maryland, College Park. "Hartley 2 exceeded all our expectations in not only scientific value but in its stark majestic beauty."

The video clip of the flyby is comprised of 40 frames taken from the spacecraft's Medium-Resolution Instrument during the encounter. The first image was taken at about 37 minutes before the time of closest approach at a distance of about 27,350 kilometers (17,000 miles). The last image was taken 30 minutes after closest approach at a distance of 22,200 kilometers (13,800 miles). The spacecraft was able to image nearly 50 percent of the comet's illuminated surface in detail.
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http://www.planetary.org : Hartley 2 compared to other comets, and in motion 3D
Nov. 5, 2010 | 16:17 PDT | 23:17 UTC

By Emily Lakdawalla

I had to catch up with tasks left undone at home today and didn't have time to write up my notes from the Hartley 2 press briefing, for which I apologize. I'll leave you for the weekend with three cool Hartley 2 pictures.

First, I've composed a montage of all five comets whose nuclei have been imaged directly by spacecraft, to scale with each other, sized for inclusion in your favorite digital presentation software. Hartley 2 is the smallest comet ever visited by a spacecraft!
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Comets visited by spacecraft
As of November 5, 2010, five comet nuclei had been directly imaged by flyby spacecraft. They are shown here to scale with each other, at 20 meters per pixel (in the click to enlarge version). Credit: Halley: Russian Academy of Sciences / Ted Stryk. Tempel 1 and Hartley 2: NASA / JPL / UMD. Borrelly: NASA / JPL / Ted Stryk. Wild 2: NASA / JPL. Montage by Emily Lakdawalla.
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Hartley 2 compared to the International Space Station
Just for fun, a size comparison of the International Space Station (upper left corner) and Hartley 2's nucleus. Credit: NASA / JPL / UMD / comparison by Emily Lakdawalla
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3D animation of comet Hartley 2's nucleus
Use red-blue glasses to see the 3D effect. To compose this animation of the nucleus of comet Hartley 2, Daniel Macháček used Squirlz Morph to morph among the five images of the nucleus that were released by the Deep Impact team on the day of the flyby, November 4, 2010, in a process explained here. Then Luca Cassioli took sequential frames from the morphed animation and used them as left and right images in this animated GIF. Credit: NASA / JPL / UMD / Daniel Macháček / Luca Cassioli
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[youtube]http://www.youtube.com/watch?v=5IlnueAk1dM[/youtube]
planetsocblog | November 05, 2010

Credit: NASA / JPL / UMD
 
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3488

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Thank you very much EarthlingX.

Like that one that shows the size of the ISS as compared. Shows how large the ISS is or how small Comet 103P/ Hartley 2 is, dependent on whether or not you are a glass half full or glass half empty person.

I think 103P/Hatrly 2 must be the second smallest natural body seen up close after Asteroid 25143 Itokawa though 243 Ida's moon Dactyl is of similar size.

Andrew Brown.
 
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scottb50

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Just my opinion but it looks like the ends are encrusted with material picked up during the Comets travels, the pinched waist area being closer to the nucleus of the object. All of the jets and activity appear to be involved with the accumulated debris at either end.

This indicates, to me, that Comets and asteroids are the same thing, the orbits they are in defining the difference by extended periods Comets have to build their outer coatings further away from the Sun in elongated orbits while asteroids generally follow more circular orbits. Encounters with planets and orbital changes could be the defining difference as the mass of similar size Comets and asteroids seem to be pretty consistent, especially when you discount the higher accumulation the Comet acquires in it's extended journey.
 
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Cosmicvoid

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I agree with the opinion that someone posted, maybe earlier in this thread or maybe a different thread, that the pinched waist suggests that the two coarsely textured end blobs are moving apart. The boundary between the waist and the coarse parts is short/narrow, suggesting a fracture. I'd bet the waist area has a lower density than the ends because the debris is being "stretched" between the two denser parts.
 
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3488

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scottb50":be0m438t said:
Just my opinion but it looks like the ends are encrusted with material picked up during the Comets travels, the pinched waist area being closer to the nucleus of the ob............
Hi scott,

Interesting thought. It is likely that some 'crud' would have been collected, but compared to the mass of the original body it would be very minor. It seems likely that thos particular comet is generally icy with a carbonaceous / rock mixture.

Unfortunately, due to 103P/Hartley's low mass & Deep Impact's high speed pass @ 12.3 KMS, I would not expect there to be gravity data (unlike Galileo passing 243 Ida & 951 Gaspra & Rosetta passing 21 Lutetia, where the objects passed were very much larger & much more massive), so it would be unlikely that we can get a density, I might be wrong, but I think that is the case.

Certainly a former resident of the postulated Oort Cloud before coming closer in, repeated encounters with the outer planets shrunk the orbit, with IIRC in 1971 (Wayne will know more than me about this particular aspect) the current orbit being achieved by a closish pass of Jupiter.

So looks like a relative newcomer to the inner solar system. I can see why after 85P / Boethin had disintigrated why 103P / Hartley 2 was chosen. Also the fact that it is almost certainly a contact binary comet (not known till last Thursday), really it is TWO comets joined together with the smaller portion appearing far more active. We'll know far much more when the temperature & infrared overlays are done & analyzed.

Cosmicvoid":be0m438t said:
I agree with the opinion that someone posted, maybe earlier in this thread or maybe a different thread, that the pinched waist suggests that the two coarsely te.............
Hi Cosmicvoid.

I am not sure that the two courser ends are pulling apart, there is no reason as to why they would, if anything the opposite is more likely as the rotation of the comet slows down over time. It is more likely the 'neck' or 'waist' is a dusty rubble infill.

The 'neck' or 'waist' appears to be inactive in as much as there are no jest emanating from it at all, the resolution of these images is more than sufficient to clearly show that, the jets are emanating from the lobes, particularly the smaller one. Yes I agree that the 'neck' or 'waist' will likely be of lower density than the two bouldery strewn masses which are more likely to be solid coherent bodies joined together.

This is fascinating stuff & thank you both for your thoughts, you gave my solitary brain cell a good workout. :mrgreen:

Andrew Brown.
 
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scottb50

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3488":kklkyq3i said:
I am not sure that the two courser ends are pulling apart, there is no reason as to why they would, if anything the opposite is more likely as the rotation of the comet slows down over time. It is more likely the 'neck' or 'waist' is a dusty rubble infill.

The 'neck' or 'waist' appears to be inactive in as much as there are no jest emanating from it at all, the resolution of these images is more than sufficient to clearly show that, the jets are emanating from the lobes, particularly the smaller one. Yes I agree that the 'neck' or 'waist' will likely be of lower density than the two bouldery strewn masses which are more likely to be solid coherent bodies joined together.

This is fascinating stuff & thank you both for your thoughts, you gave my solitary brain cell a good workout. :mrgreen:

Andrew Brown.
I'm more inclined to think the waist area is more solid then it appears to be representing the actual Comet itself. Scrape away the rubble at both ends and the dumb-bell would be the potato shape common to asteroids that have been surveyed. One idea why both ends are similar might be a shifting of mass, the end facing in accumulates more mass until the rotation starts to wobble and the ends change places. The closeups recently of Lutetia, I believe it was, clearly show accumulation of ice of some sort, the one bowl area looking like a ski resort.

The close approaches to the Sun and the subsequent heating of the surface would suggest more condensed gasses would build up while the more consistent environment of asteroids would have temperatures closer to the surrounding environment.
 
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MeteorWayne

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Sorry, scott, have to disagree here. As I said when I first saw the image, it looks like two icy chunks (a "contact binary") with dust filling in around the junction. We have seen this before on asteroids, how the dust smoothly fills in the gravitational low spots.

Also, the comet rotates far two slowly for the two chunks to pull apart (~ 18 hrs), and the dust in the middle insulates the ices at the junction. You can see that there are no jets there, only on the exposed icy ends.

MW
 
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EarthlingX

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herschel.esac.esa.int : Herschel observes EPOXI-encounter comet Hartley 2.

Images above left to right: montage of EPOXI images (NASA), SPIRE, PACS, and HIFI images (ESA/Herschel/HssO Consortium), see the HssO note for more information.

Herschel is taking part in an extraordinary worldwide astronomical campaign to study comet Hartley 2 before, during, and after the flyby by the NASA EPOXI (Extrasolar Planet Observation and Deep Impact Extended Investigation) mission, with closest approach on 4 November 2010. Hartley 2 passed just 0.11 AU (16.4 million km) from Herschel on 20 October 2010. Herschel has obtained unique sensitive far-infrared continuum images constraining the size of the large dust particles, while spectra reveal the distribution of water molecules released from the nucleus as about 230 kg of ices evaporate every second.
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kg

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3488":2h3crok4 said:
.... Yes I agree that the 'neck' or 'waist' will likely be of lower density than the two bouldery strewn masses which are more likely to be solid coherent bodies joined together....
Andrew Brown.
Hi Andrew, exciting stuff!
I can't help noticing similarities between comet Hartley 2 and 25143 Itokawa. Do you think it is common for lower density material to migrate to the center of rotation rather than to the surface of objects this size? Seems like an interesting process.
 
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scottb50

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MeteorWayne":1xkywf59 said:
Sorry, scott, have to disagree here. As I said when I first saw the image, it looks like two icy chunks (a "contact binary") with dust filling in around the junction. We have seen this before on asteroids, how the dust smoothly fills in the gravitational low spots.

Also, the comet rotates far two slowly for the two chunks to pull apart (~ 18 hrs), and the dust in the middle insulates the ices at the junction. You can see that there are no jets there, only on the exposed icy ends.

MW
I probably didn't say what I wanted as clearly as I could have, I would agree the neck area is covered with much finer material. What I was trying to say is the core may be a solid mass rather then a composite.
 
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MeteorWayne

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NASA Announces Comet Encounter News Conference

WASHINGTON -- NASA will hold a news conference at 1 p.m. EST on Thursday, Nov. 18, to discuss new scientific findings from the recent EPOXI mission spacecraft encounter with comet Hartley 2.

The news conference will originate from the NASA Headquarters auditorium at 300 E St. SW in Washington. It will be carried live on NASA Television.
The news conference participants are:
-- Michael A'Hearn, EPOXI principal investigator, University of Maryland
-- Jessica Sunshine, EPOXI deputy principal investigator, University of Maryland
-- Tim Larson, EPOXI project manager, Jet Propulsion Laboratory, Pasadena, Calif.
-- Pete Schultz, EPOXI scientist, Brown University

NASA's EPOXI spacecraft successfully flew past comet Hartley 2 on Nov. 4, providing scientists the most extensive observations of a comet in history.

For NASA TV streaming video and downlink information, visit:

http://www.nasa.gov/ntv

For more information about NASA's EPOXI mission visit:

http://www.nasa.gov/epoxi
 
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3488

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Thanks Wayne,

I literally just saw that myself. I will be around to watch that live.

Still without sound, but can see what is being shown. Will be interesting for sure, very interesting. Hopefully some IR, temperature & other spectral data, perhaps the odd deconvoluted HRI image too.

Andrew Brown.
 
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MeteorWayne

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I'll do scribblenotes, so will try and capture the essence of the sound :)
 
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3488

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Thanks Wayne,

I am looking forward to these updates very much.

Hopefully as with 9P/Tempel 1, there will be temperature & IR overlays, as well as 'geographical' grids, etc, overlays. Deep Impact has really excelled, worth every cent spent on her, the science is just mind blowing.

Will be interesting to see what the future holds, for Deep impact. Such a shame she is so low on propellant now, a week prior to 103P/Hartley 2 was already down to the final 5 KG from the original 85 KG at launch.

Mind you NASA are great at puilling rabbits out of hats so to speak!!!

I have a feeling that Deep Impact may be used for a kind of minor KEPLER mission, monitoring stars for transiting planets. However, we never know, perhaps a Near Earth Asteroid or another comet may be reachable if not far from Deep Impact's current orbit.

Andrew Brown.
 
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3488

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Enlarged sharpened crop of deconvolved High Resolution Imager of nucleus of 103P / Hartley 2.


Abundance of gasses in the coma of 103P / Hartley 2.


C02 in coma of 103 P / Hartley 2.


Andrew Brown.
 
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3488

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MeteorWayne":21n9ink0 said:
Scribblenotes part 1:

WOW!!!

More soon :)
I like what I've seen so far Wayne. Huge WOW indeed. :mrgreen: :mrgreen: :shock:

My stupid FireFox crashed out twice, so I think for sure I will ditch it & go over to IE8. It appeared NASA TV crashed it. :shock:

If that is so, than it's no good.

Anyway, the HRI deconvolved image of an approx 700 metre section of the larger portion of the nucleus, is amazing. The extra detail is stunning, the surface is even rougher than suggested by the previously MRI images. Ice boulders strewn around, some in clusters, a few in profile on the limb, some looked stacked up (perhaps rocky boulders sheltering ice underneath, like pedestals). Also some harder ice outcrops too.

'Blizzard' of ice particles enamating from the nucleus too. Size range from golf ball to football, but very loosely consolidated, like a heap of soft aerated snow, rather than solid ice like hail.

I hope we get to see similar soon of the entire nucleus including the 'neck' in HRI 'to see if that looks so smooth in 5x extra resolution.

Four times as much CO2 being ejected than H2O, reasonable perhaps if 103 P / Hartley 2 is indeed a relative new comer to the inner solar system, as the lower temperature volatiles will sublimate before higher temperature ones.

Clickable thumbnail HRI view of cometary 'blizzard' of ice particles. The nucleus is out of the frame to the lower right.


Clickable thumbnail MRI view of the over exposed nucleus & the inner coma.


Andrew Brown.
 
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EarthlingX

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Andrew, IE8 is a bad idea, for many OT reasons - try updating plugin for video, flash or whatever is causing the trouble.


SDC : Comet Pelted NASA Probe with Bits of Ice During Flyby
By Mike Wall
SPACE.com Senior Writer
posted: 18 November 2010
07:02 pm ET



A NASA spacecraft had to survive a cosmic snowstorm once it reached a distant comet two weeks ago, but still managed to beam back photos of never-before-seen cometary features and behavior, scientists announced today (Nov. 18).

The Deep Impact probe probably got hit at least nine times by ice particles during its flyby of Comet Hartley 2 on Nov. 4 but did not sustain any noticeable damage, the scientists said.

The spacecraft flew to within 435 miles (700 kilometers) of the small, active comet and witnessed a blizzard of water ice around its nucleus — something never observed before, researchers said. [New photo of the comet blizzard]

"When we first saw this, our mouths just dropped," Pete Schultz of Brown University, a scientist on the flyby mission team, told reporters. "To me, this whole thing looks like a snow globe that you've shaken."
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http://www.planetary.org : Deep Impact at Hartley 2: Two weeks after the flyby
Nov. 18, 2010 | 12:52 PST | 20:52 UTC

By Emily Lakdawalla

Today the Deep Impact/EPOXI science team held a press briefing that followed up on their very successful flyby of two weeks ago, a status report on what they can say so far about the science that's coming out of the encounter. There's still years worth of work to be done with this data set, and actually the spacecraft hasn't even stopped taking Hartley 2 data yet; according to the timeline, it is still snapping photos every half an hour and will continue to do so until the last day of November.

Before I launch into detail, here were the major points from the briefing:

* Hartley 2's jets are spitting out big fluffy snowballs, some of which can be individually tracked in sequential images. (Cool.)
* These snowballs did absolutely no damage to the spacecraft, although close examination of its telemetry revealed that it may have gotten hit by very low-mass particles nine times during the ten minutes around closest approach.
* The comet has a split personality, with carbon dioxide-powered jets spitting ice and dust out of its ends, but behaving more like Tempel 1 at its waist.
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http://www.planetary.org : Asteroids and comets to scale, including Hartley 2
Nov. 18, 2010 | 09:52 PST | 17:52 UTC

By Emily Lakdawalla

Just in time for today's Deep Impact press briefing, which you can watch on NASA TV in a few minutes: I've updated my montage of all the asteroids and comets that have been visited and photographed to include Hartley 2. This required no major rearrangement from the last update, since Hartley 2 is so tiny; you can see it grouped with the rest of the comets to the lower right of gigantic Lutetia, which dominates the scene.


All asteroids and comets visited by spacecraft as of November 2010
Credits: Montage by Emily Lakdawalla. Ida, Dactyl, Braille, Annefrank, Gaspra, Borrelly: NASA / JPL / Ted Stryk. Steins: ESA / OSIRIS team. Eros: NASA / JHUAPL. Itokawa: ISAS / JAXA / Emily Lakdawalla. Mathilde: NASA / JHUAPL / Ted Stryk. Lutetia: ESA / OSIRIS team / Emily Lakdawalla. Halley: Russian Academy of Sciences / Ted Stryk. Tempel 1, Hartley 2: NASA / JPL / UMD. Wild 2: NASA / JPL.
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[youtube]http://www.youtube.com/watch?v=_4EE_6p62yI[/youtube]
JPLnews | November 19, 2010

The story of NASA's EPOXI mission, which flew by comet Hartley 2 on Nov. 4, 2010

[youtube]http://www.youtube.com/watch?v=5p3fm_NuEuc[/youtube]
JPLnews | November 19, 2010

NASA's EPOXI mission spacecraft spots a cometary snow storm with basketball-sized, fluffy ice particles at comet Hartley 2.

[youtube]http://www.youtube.com/watch?v=LnAjWtsINnQ[/youtube]
NASAtelevision | November 18, 2010

[youtube]http://www.youtube.com/watch?v=j0x-j1D4oJE[/youtube]
NASAtelevision | November 18, 2010

Scientists at a NASA briefing held in Washington Nov. 18 discuss the data collected by the EPOXI mission on its recent flyby of comet Hartley 2. Travelling at a speed of 27,000 mph, the spacecraft passed Hartley 2 at an altitude of about 435 miles from the comet's surface, close enough to reveal details of its nucleus and give scientists the most extensive look at a comet in history. Comets are remnants of the formation of our solar system more than 4-and-a-half-billion years old.
 
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