Deep Impact/EPOXI

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MeteorWayne

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Exactly 1 day, and about 1.064 million km away from the comet, with 2.534 million km left to fly!
 
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MeteorWayne

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About an hour and a half ago, EPOXI turned it's high gain antenna away from earth to begin the encounter observations. For the next 18 hours or so, it will be filling it's memory with all that juicy data. NASA TV will cover the close encounter period, 13:30-15:15 UTC (9:30-11:15 AM EDT). CA is at 13:50 UTC, 09:50 EDT. JPL is expected to maintain contact with the craft, though data download will not occur until the high gain antenna points back at earth ! 14:20 UTC, 10:20 AM EDT.

MW
 
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3488

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Thanks Wayne for that update.

I will try & leave work early tomorrow for the image releases.

Judging by the crude Arecibo Radar images, the nucleus looks a lot like the comet Borelly nucleus, though of course at such a low resolution, it is hard to tell.

Andrew Brown.
 
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MeteorWayne

Guest
PASADENA, CALIF. – Mission controllers at NASA's Jet Propulsion Laboratory in Pasadena, Calif., have relayed final instructions to their comet-bound spacecraft today, Nov. 3. The new programming will guide NASA's EPOXI mission through its close approach with comet Hartley 2, scheduled for tomorrow, Nov. 4, at about 7 a.m. PDT (10 a.m. EDT).

"The last 1 million kilometers are always the hardest," said Tim Larson, EPOXI project manager from JPL. "But we've prepared thoroughly for this day and are confident that come tomorrow morning, we'll be getting the kind of data and imagery that will keep our scientists busy for months to come."

Today at 7 a.m. PDT (10 a.m. EDT), NASA's EPOXI mission was about 1,064,900 kilometers (661,700 miles) from Hartley 2 and closing at a rate of 12.3 kilometers (7.6 miles) per second. Tomorrow at the same time, the spacecraft will be at its closest approach distance to the comet -- approximately 700 kilometers (435 miles) away from its nucleus. All the while, the spacecraft's two imagers and one infrared instrument will be acquiring data.

"We are really looking forward to this because the comet has shown so many surprises, both in the data from EPOXI and the data from our many collaborators, over the last several months," said EPOXI principal investigator Mike A'Hearn from the University of Maryland, College Park."

When the EPOXI mission spacecraft is 18 hours and 798 thousand kilometers (496 thousand miles) away, it will lock its instruments on the comet and begin its encounter phase data collection. As the distances between man-made machine and mysterious space dirtball closes, the frequency of image-taking will increase, reaching a crescendo in the minutes surrounding approach. All data collected during encounter phase will be loaded into spacecraft memory for later playback.

If all goes as planned, about 50 minutes before closest approach, the spacecraft's onboard autopilot – AutoNav Mode – is expected to go active. When in AutoNav Mode, the spacecraft receives attitude (pointing) instructions from its computer to help keep the comet's nucleus centered in spacecraft's imagers.

"We're using AutoNav Mode because our mission control is 23 million miles away from the spacecraft at time of encounter," said Larson. "Any command we would send to the spacecraft would take 75 seconds to get there. Not the kind of thing you want to do when you're talking about hurtling past a 2.2 kilometer-wide object [1.36 miles] at 27,500 miles per hour [about 44,256 kilometers per hour]." AutoNav Mode works by having the spacecraft's Medium-Resolution Imager look for the brightest light source in the sky (excluding the sun). It then assumes that the bright light source must be the comet's nucleus and adjusts the spacecraft's attitude accordingly to keep its imagers centered.

"This spacecraft's AutoNav worked great during its prime mission in 2005 at comet Tempel 1," said Larson. "While that comet's shape provided one central light source, new data from Arecibo indicate that comet Hartley 2 is more elongated and could have two unique bright spots on the ends. If that is the case, we expect Auto Nav to make a decision on which of the two is brightest and focus on that spot."

The EPOXI team expects to begin receiving imagery from the spacecraft starting about 30 minutes after closest approach. The first images received will be those that were taken when the spacecraft was 18 hours out from its target. They will depict the comet nucleus as little more than a point of light, with the fuzzy coma surrounding it. A few of the close-approach images should be received on the ground one hour after the event occurs.

"Those early images may not be the 'money shot,' but we on the science team will prize them just as well, as they will help us further understand the nature of comets," said A'Hearn. "And when we first see those images surrounding closest approach, we are looking forward to yet another type of nucleus compared to any we have seen up close thus far."
 
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jumpjack2

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Does anybody know of any webpage showing live minute-by-minute mission status, as sometimes happens for NASA missions?
 
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MeteorWayne

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Amazingly Outstanding Images.

Looks like AutoNav worked almost perfectly.

These images are from the medium range imager, many more images will be coming over the next 10 hours of download.
 
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3488

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Hi Guys,

I'm here too. Thank You very much EX.

Enlarged, sharpened screen dump from me. Nucleus of 103P/Hartley 2.


Credit: NASA / JPL / UMD.

Andrew Brown.
 
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3488

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Cleaned up one here, clearly showing ice boulders on the nucleus.


Credit: NASA / JPL / UMD.

Andrew Brown.
 
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EarthlingX

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Beautiful, very nice job :cool:

I caught a bit bigger image, until they are on-line :

 
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MeteorWayne

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I keep getting the impression:

(25143) Itokawa :)

Then again, it looks like most of the deranged potatos on the spectrum from asteroid to comet careening about the inner solar system :lol:
 
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3488

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Another larger one here of 103P/Hartley 2. From JPL site, I have enlarged sharpened it.


Credit: NASA / JPL / UMD.

Andrew Brown.
 
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EarthlingX

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http://www.planetary.org : Close approach images of Hartley 2!
Nov. 4, 2010 | 08:24 PDT | 15:24 UTC

By Emily Lakdawalla

What a dramatic and cool photo! An asteroid with two lobes like Borrelly, lumpy and bouldery like Itokawa, with gorgeous active jets, dramatically lit. Well done, Deep Impact team!

Right now I'm just posting one of the five highest-resolution images...I'm going to work on some prettified versions good for embedding. Look for those as soon as I can get them live, maybe half an hour to an hour.

Deep Impact high-resolution view of Hartley 2
Deep Impact took this photo of Hartley 2 near the closest approach of its flyby on November 4, 2010 at 13:59 UTC. Credit: NASA / JPL / UMD
 
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3488

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MeteorWayne":1ka6iwne said:
I keep getting the impression:

(25143) Itokawa :)

Then again, it looks like most of the deranged potatos on the spectrum from asteroid to comet careening about the inner solar system :lol:
Hi Wayne,

Just fantastic ain't it, innit?????? :lol: :lol: :lol: :lol:

Yes I agree, 25153 Itokawa lookalike & also similar to Comet Borelly from Deep Space 1.

25143 Itokaea, a type S asteroid, very different type of object altogeter, but the similarity in appearance is striking!!!!

Later I will down load Bitmaps & do crops & enlargements from those. The two done so far are pretty crude sharpened JPEGS.

Andrew Brown.
 
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3488

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Guess where I got this from EarthlingX. Thank you so much.

An enlargement sharpened view from EarthlingX post above. 103P/Hartley2 from HRI.


Credit: NASA / JPL / UMD.

Andrew Brown.
 
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EarthlingX

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Very nice :)

Official images online :

epoxi.umd.edu : Encounter Imagery
The EPOXI team expects to begin receiving imagery from the spacecraft starting about 30 minutes after closest approach, which is at approximately 14:00 UT (7:00 am PDT). The first images received will be those that were taken when the spacecraft was 18 hours out from its target. They will depict the comet nucleus as little more than a point of light, with the fuzzy coma surrounding it. A few of the close-approach images should be received on the ground one hour after the event occurs.
 
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3488

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Thank You very much EarthlingX for that link. There is much I can use there.

Has there been anything said of the actual size of the nucleus & actual closest approach distance? I have no saound, my sound card is knackered.

In some blurb yesterday, it was mentioned the nucleus would appear approx 170 pixels long, on these close images though appears larger than that!!!!

Andrew Brown.
 
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MeteorWayne

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Another interesting aspect is the smooth area between the bouldered ends. It really looks like two lumps stuck together with a smooth neck filled in in between.
 
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3488

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I wonder Wayne, if the larger ends have gravitationally attracted those boulders & icy regolith, leaving the central 'neck' clean?? If so, the 'neck' will be bedrock / bedice, & will be interesting when we get the compositional data in, as the 'neck' will be what the main body of Hartley 2 is made from.

Or do you think this is a contact binary comet, with infill??

Also there appear to be no craters.

Andrew Brown.
 
E

EarthlingX

Guest
www.planetary.org : Five close-approach images of Hartley 2 by Deep Impact, with commentary
Nov. 4, 2010 | 08:58 PDT | 15:58 UTC

Here's the five close-approach images of Hartley 2 captured today, November 4, 2010, by the Deep Impact spacecraft, collected into one file. Boy, do these images reward close examination! Check them out:

Five close-approach images of Hartley 2 by Deep Impact
About an hour after its closest approach of Hartley 2, Deep Impact downlinked five precious images taken during the nearest part of its flyby. The top two images were taken 82 and 16 seconds before closest approach, and the bottom three 18, 57, and 117 seconds after closest approach (image times are 13:58:07, 13:59:13, 13:59:47, 14:00:26, and 14:01:26 UTC on November 4). They show a very active comet with numerous jets. The comet's nucleus has two lobes. The lobe ends are noticeably lumpy, possibly bouldery. The lobes are connected by a thin neck that is much smoother. In the images taken after closest approach under more dramatic lighting, one can see comet jets that originate on the night side of the comet and rise into sunlight. Credit: NASA / JPL / UMD / montage by Emily Lakdawalla
...
 
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