It doesn't look like there are any plans for an extended mission.

........also I wonder if the focus problem with the HI camera has had a more serious efect on the science than anticipated.

I loved the animated sequence showing the crater formation and the 'jet' it caused. I can't wait to see some of the other processing in the next few days.

I wonder if the new jet has changed the trajectory at all (you would think it would have to have). I've seen several places where people have expressed concern that they will have knocked the comet into an Earth collision course. I find it interesting that people think Nasa would even consider attempting doing something like that. I mean, the first thing they probably looked at was "will this endanger the Earth in any way?" There will always be the Chicken Littles I guess.

Well, the 'electrical comet' people will have reassess their theories, I didn't see any lightening bolts leaping off the surface toward the copper impactor.

I'm sure there will be some adjustments necessary to mainstream comet structure ideas too though...don't think they expected the craters.

Eric P / MizarKey

I'm still finding it hard to believe think of those circular features as craters, the shadows are all wrong, but I'll reserve judgement. The circular feature at left in this image:

http://pirlwww.lpl.arizona.edu/~perry/images/impact48.jpg

maybe a crater though

Here I've tinkered with the brightness to see the terminator area better.



A lovely new world! Despite what A'Hearn said I think this is quite a lot like Borrelly in many respects - but we see it a lot better. It's VERY different from the weird Comet Wild-2, with its amazing spiky hills and scarps. The top is rotating towards us, meaning cometary north is to the right (the new IAU definition of north on objects like these).

Note how the two smooth patches give the appearance of lying in the the central portions of broad shallow depressions. A proper shape model will be made later, so I hope it confirms this. Despite VP's comments, I don't have a problem interpreting the circular features as impact craters, though presumably if the artificial impact tells us anything it should be that natural impacts will trigger venting and the crater will evolve rapidly. But the dark shading VP mentions looks to me like the outer part of the rim on one side, and the inner part of the rim on the opposite side... it looks OK as a crater to me. Well, we'll see... I have my opinions, but I've been wrong before. (just ask my kids!)

Phil

Let me get this straight: they're not sure if they see the crater? The whole point of the mission was to look inside the crater to see the interior of the nucleus! Don't get me wrong, the nucleus photos are great and the impact photos are absolutely spectacular, but what about the science?

I don't think it's that bad- the main way they planned to see what was in the crater was to watch that stuff being blasted out into space, rather than look at what was left behind in the hole- they will have lots of data on what's inside the comet. But seeing the crater would tell a great deal about the strength of the nucleus and about impacts in general. If they can't see the crater through the the plume, it will be a disappointment, but not a disaster.

I see. I thought they wanted to see the layers of the interior of the comet in cross-section. Although it seems like the majority of the imaged are still being downlinked.

Trying to make sure I understand the geometry of the image: in the lookback image, the really bright spot is the sun, right? (As opposed to the plume from the impact)

I though we would get better lookback images for mapping.

MiniTES, the brightest spot in the lookback image is the plume. The illuminated part of the nucleus shows the general direction to the sun, but it's far off to the side. The plume looks extra-bright in forward-scattered light.

Phil

Actually, the scientific seriousness of the HRI focusing problem has been greatly diminished by the other problem: the fact that the ejecta cloud utterly hid the impactor crater. When you read A'Hearn's and Belton's original article setting forth the science rationale for this mission ( http://deepimpact.jpl.nasa.gov/science/cospar-ms.pdf ) , they DO emphasize looking for layering in the crater walls as one of its most important justifications -- and it's precisely for that reason that they wanted such a very high-powered HRI with a top resolution of "1 meter/pixel", since the layering structure may well be that fine.

Well, of course, the obscuring ejecta cloud has totally ruined that scientific goal for the mission, and would have in any case. And since the Impactor Camera imaged the approach side of Tempel every bit as well as a perfectly focused HRI would have (its resolution and viewfield at 140 km distance was the same as the HRI's at its own minimum distance of 700 km, and at that point the Impactor Camera was still totally non-sandblasted), virtually the only thing we ended up actually losing from the HRI problem was somewhat sharper photos of the OTHER side of the nucleus. Moreover, when you compare the deconvoluted HRI photos of the impact itself with those from the MRI ( http://www.nasa.gov/mission_pages/deepimpa...a/pia02123.html and http://www.nasa.gov/mission_pages/deepimpa...a/PIA02131.html ), it's clear that deconvolution -- even if it didn't completely solve the HRI problem -- has still allowed the creation of photos maybe 3 times sharper than those from the MRI (as opposed to the originally hoped-for 5 times).

But that ejecta cloud -- whose power to blot out the impact crater was always a very strong possibility, even if it hadn't been remotely as big as it actually turned out to be -- raises the question: just how good, really, was the science rationale for this mission? (Hawaii's Jeffrey Bell, playing his usual role as the Skeleton at the Feast, has been raising this point in E-mails to me for years.) It's now clear that, if we really wanted to study the comet's surface layering, it might have been a far more dependable technique to simply put a radar sounder on the craft -- which would also have covered a vastly wider area on the surface, perhaps incuding sites of activity, and could have been used on more than one comet. (The sounder's antenna could have been put in the "shadow zone" protected by the craft's forward dust shield.) Moreover, by eliminating the great mass and cost of the Impactor, we could also easily have added gas and dust-impact mass spectrometers a la CONTOUR and Stardust. In short, this mission -- for less cost -- could have instead been a vastly improved version of the multi-comet CONTOUR mission. Just about the only thing we actually got out of Deep Impact that such an alternative mission couldn't have provided was the data the impact may have provided on the chemical composition of really deeply buried subsurface ices -- and was this enough to compensate for the other stuff we passed up?

This returns me to something I've wondered about for years: just how did Deep Impact actually get selected? Its selection was a total surprise to me; it muscled ahead of other Discovery finalists -- Aladdin, and a VESAT or VESPER Venus orbiter -- which were not only finalists this time but had been during the previous selection, too (which D.I. never had been). Is it possible that Dan Goldin intervened and ordered the selection of Deep Impact as yet another of his harebrained NASA PR stunts with questionable science return (Mars Pathfinder, with its cute but scientifically mediocre rover and not-very-efficient airbag system; the cancelled 2003 miniature Mars Airplane; the proposed all-girl Shuttle flight; the cancellation of a sensible 2003 Pluto probe in favor of a far more difficult and technically sophisticated early Europa Orbiter, with the highly predictable result thaat we got neither)? I already know that NASA HQ virtually ordered the selection of Phoenix in the supposedly "independent" 2007 Mars Scout selection; we were explicitly told so at the first Mars Roadmap meeting.

Were the images taken after impact monochrome or multispectral? If multispectral, there a chance that anything "behind" the cloud might be pulled out. Actually, depending on opacity, this might happen with monochrome images too.

Bruce: You bring up some interesting points. However, one thing to note about Deep Impact is that the media coverage of it, at least in online sources, is about as good as anything I've seen on an unmanned mission, and probably better, and I fully expect to see photos of impact on the front page of every major newspaper tomorrow morning. The explosion and the July 4th impact seems to really provide instant gratification for those who don't like waiting for all that boring science to come out of these missions. After all, why wait a week or two to wait for the data to be downlinked and some extremely basic conclusions made about the comet when you can ask questions about tunnels on the nucleus today?

That said, I think there is some valuable science here. We will have some good information on the interior makeup of the comet if the spectroscopy goes well, and we already have some good images. And you must admit that whatever their scientific value may be, those impact images are jaw-dropping. Usually you only see stuff like that in artists' conceptions! Bruce, do you know if the July 4th date was chosen intentionally or "ordered" by our good friend Mr. Goldin?

To Ted: both the HRI and MRI images were multispectral -- but as yet, I don't have the wavelengths or even the number of filters. I'll continue digging. (There is a good simulation of what they were hoping for from the HRI, when it came to observing layers in the imact crater walls, at http://deepimpact.jpl.nasa.gov/tech/hri.html .)

I think there are six colors in the MRI filter wheel, if I recollect an article in the Planetary Report correctly.

Edit: This source gives nine colors for MRI: http://www.deepimpact.umd.edu/collaborativ...IntervSheet.pdf

Edit 2: This source gives nine for both. Nothing on the wavelenghts they let in, though. http://www.beltonspace.com/bsei_web_page_g000000.pdf