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Deep Impact Realtime Thread
djellison
post Jul 4 2005, 04:52 AM
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Well - impactor TCM 1 went well - <0.3% error and it's on course for a nominal impact time. PI has suggested that the comet is Banana shaped and we're going to hit the end of it which looks a little triangular ohmy.gif
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Guest_BruceMoomaw_*
post Jul 5 2005, 01:48 AM
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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.
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MiniTES
post Jul 5 2005, 02:38 AM
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QUOTE (BruceMoomaw @ Jul 5 2005, 01:48 AM)
... 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.
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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?
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Posts in this topic
- djellison   Deep Impact Realtime Thread   Jul 4 2005, 04:52 AM
- - djellison   A rather rough and ready HRI picture on NASA TV - ...   Jul 4 2005, 05:09 AM
- - djellison   TCM 2 is in progress - estimated to be 40ish secon...   Jul 4 2005, 05:19 AM
- - hendric   Sounds like someone was concerned about microradia...   Jul 4 2005, 05:20 AM
- - hendric   Somebody just got up and ran off..."I told yo...   Jul 4 2005, 05:21 AM
- - djellison   I assume this is the calculated pointing error for...   Jul 4 2005, 05:22 AM
- - hendric   Figures...Nasa TV is showing images of the HRI. ...   Jul 4 2005, 05:23 AM
- - deglr6328   Did I get that right? They're doing (near) rea...   Jul 4 2005, 05:24 AM
- - hendric   Yep. On their laptops, no less. I guess Mike...   Jul 4 2005, 05:28 AM
- - djellison   Yup "Two days"...lmfao - 60 seconds Do...   Jul 4 2005, 05:31 AM
- - hendric   holy...I thought the tv camera defocused, but thos...   Jul 4 2005, 05:36 AM
- - djellison   For those with access - Sky News is carrying NTV a...   Jul 4 2005, 05:36 AM
- - djellison   Last TCM calculations suggest again, 2ish m/sec D...   Jul 4 2005, 05:38 AM
- - deglr6328   Final ITM (ITM 3) occurs in <3 min. As I unders...   Jul 4 2005, 05:39 AM
- - hendric   "Near real time" my butt. The Image Vie...   Jul 4 2005, 05:44 AM
|- - Bob Shaw   Good images of the nucleus - looks like a bent Enc...   Jul 4 2005, 06:07 AM
|- - Bob Shaw   A screengrab of the nucleus:   Jul 4 2005, 06:15 AM
- - djellison   FInal burn manouver complete - accurate to within ...   Jul 4 2005, 05:45 AM
- - deglr6328   Final TCM burn error less than 1/4 of a %!...   Jul 4 2005, 05:45 AM
- - djellison   10 seconds to go   Jul 4 2005, 05:51 AM
- - djellison   Loss of Signal   Jul 4 2005, 05:52 AM
- - djellison   WOoooooooooooooooooooooooooo - the pictures Doug   Jul 4 2005, 05:52 AM
- - djellison   Wow - this is like ranger - amazing images coming...   Jul 4 2005, 05:53 AM
- - deglr6328   WOW! lovely!! they look far closer t...   Jul 4 2005, 05:53 AM
- - hendric   Is that a crack?? My bet is for rubble pile!...   Jul 4 2005, 05:55 AM
- - djellison   Is it wrong that I was celebrating WAYYY before th...   Jul 4 2005, 05:57 AM
- - deglr6328   It's perfect! Perfectly centered in the im...   Jul 4 2005, 05:59 AM
- - alan   "doing very well for a spaceraft about to be ...   Jul 4 2005, 06:03 AM
- - lyford   Doh - party's over here now....   Jul 4 2005, 06:03 AM
- - djellison   Just taking photographs of my TV here - with Sky N...   Jul 4 2005, 06:04 AM
- - lyford   more here http://www.scotsons-shack.com/dimages.h...   Jul 4 2005, 06:05 AM
- - lyford   kitt peak working now Kitt Peak Live Feed   Jul 4 2005, 06:07 AM
- - hendric   Deep Impact II to hit an Asteroid?   Jul 4 2005, 06:10 AM
- - deglr6328   Sub-meter res images just before impact seem to sh...   Jul 4 2005, 06:13 AM
- - hendric   Consdering they're compensating for a really l...   Jul 4 2005, 06:14 AM
- - djellison   MRI of the impact. I just have to go 'BOOOOoo...   Jul 4 2005, 06:20 AM
|- - Bob Shaw   Medium resolution image of the impact:   Jul 4 2005, 06:25 AM
|- - Bob Shaw   Doug: Gonna send the Deep Impact Team a 'Gold...   Jul 4 2005, 06:27 AM
- - Sunspot   Any reports of observations from the ground?   Jul 4 2005, 06:21 AM
- - lyford   mirror of the pre impact animation from kitt peak ...   Jul 4 2005, 06:27 AM
|- - Bob Shaw   The final flyby picture before the 'hiding fro...   Jul 4 2005, 06:32 AM
- - garybeau   The best 4th of July fireworks I ever witnessed. C...   Jul 4 2005, 06:37 AM
- - djellison   The realtime image pages are healthily updated, bu...   Jul 4 2005, 06:59 AM
- - volcanopele   Try: http://pirlwww.lpl.arizona.edu/~perry/image...   Jul 4 2005, 07:01 AM
- - alan   impact images now available on near real time imag...   Jul 4 2005, 07:37 AM
- - Sunspot   http://www.spaceflightnow.com/deepimpact/050704fau...   Jul 4 2005, 07:55 AM
- - Jyril   Faulkes Telescope images can be found here.   Jul 4 2005, 07:56 AM
- - deglr6328   Pre and post (~20 minutes) images from the Faulkes...   Jul 4 2005, 08:04 AM
|- - jaredGalen   What time GMT is the press conference on? I don...   Jul 4 2005, 08:09 AM
|- - dvandorn   Now it's off of "Momentarily" and ba...   Jul 4 2005, 08:11 AM
|- - jaredGalen   QUOTE (jaredGalen @ Jul 4 2005, 09:09 AM)Edit...   Jul 4 2005, 08:12 AM
|- - jaredGalen   WOOOHOOO!!!   Jul 4 2005, 08:13 AM
|- - jaredGalen   Wow, more hits than Cassini and MER combined! ...   Jul 4 2005, 08:15 AM
- - Sunspot   I think it should have started 10 minutes ago. ...   Jul 4 2005, 08:11 AM
- - Jyril   It should start at any time now. They're havin...   Jul 4 2005, 08:11 AM
- - Jyril   Here's a blog from Planetary Society for those...   Jul 4 2005, 08:26 AM
- - Tman   Someone did a nice animation on web: http://pla...   Jul 4 2005, 08:50 AM
|- - abalone   Still image from impactor. Impact point is in cent...   Jul 4 2005, 09:08 AM
- - Decepticon   Did anyone get the reaction of the Deep Impact Tea...   Jul 4 2005, 12:03 PM
|- - Marcel   Before and after by Hubble http://deepimpact.jpl....   Jul 4 2005, 12:52 PM
- - ilbasso   I heard the rep from ESA say that Rosetta was also...   Jul 4 2005, 01:55 PM
- - Tman   There is an QT movie that shows most approach so f...   Jul 4 2005, 03:30 PM
|- - volcanopele   QUOTE (Tman @ Jul 4 2005, 08:30 AM)There is a...   Jul 4 2005, 03:52 PM
- - djellison   It may be that it started to tumble / wobble with ...   Jul 4 2005, 03:35 PM
|- - Jyril   QUOTE (djellison @ Jul 4 2005, 06:35 PM)It ma...   Jul 4 2005, 03:47 PM
- - Jyril   The hubble image posted earlier has been updated w...   Jul 4 2005, 03:45 PM
- - volcanopele   http://pirlwww.lpl.arizona.edu/~perry/images/impac...   Jul 4 2005, 04:04 PM
- - Tman   wow, you found likely the right impact spot! I...   Jul 4 2005, 04:25 PM
|- - jaredGalen   Looks Like your spot on. I overlayed the closeup ...   Jul 4 2005, 05:59 PM
|- - jaredGalen   In fact the last one seems to fit in too here. Thi...   Jul 4 2005, 06:11 PM
- - Decepticon   Cool animations! This is a great press confe...   Jul 4 2005, 06:24 PM
- - djellison   1600GMT Press Conf Highlights Web Hits : Last 24...   Jul 4 2005, 06:25 PM
- - Decepticon   Are raw images available yet?   Jul 4 2005, 06:31 PM
- - alan   Found a couple more matches in Tman's image   Jul 4 2005, 06:36 PM
|- - jaredGalen   QUOTE (alan @ Jul 4 2005, 07:36 PM)Found a co...   Jul 4 2005, 06:48 PM
- - Sunspot   It doesn't look like there are any plans for a...   Jul 4 2005, 06:48 PM
- - MizarKey   I loved the animated sequence showing the crater f...   Jul 4 2005, 06:49 PM
- - volcanopele   I'm still finding it hard to believe think of ...   Jul 4 2005, 07:01 PM
- - Phil Stooke   Here I've tinkered with the brightness to see ...   Jul 4 2005, 09:10 PM
|- - MiniTES   Let me get this straight: they're not sure if ...   Jul 4 2005, 10:06 PM
|- - john_s   QUOTE (MiniTES @ Jul 4 2005, 10:06 PM)Let me ...   Jul 4 2005, 10:13 PM
|- - MiniTES   QUOTE (john_s @ Jul 4 2005, 10:13 PM)I don...   Jul 4 2005, 10:20 PM
|- - MiniTES   Trying to make sure I understand the geometry of t...   Jul 4 2005, 11:35 PM
- - Decepticon   I though we would get better lookback images for m...   Jul 5 2005, 12:10 AM
- - Phil Stooke   MiniTES, the brightest spot in the lookback image ...   Jul 5 2005, 12:40 AM
- - BruceMoomaw   Actually, the scientific seriousness of the HRI fo...   Jul 5 2005, 01:48 AM
|- - tedstryk   Were the images taken after impact monochrome or m...   Jul 5 2005, 02:23 AM
|- - MiniTES   QUOTE (BruceMoomaw @ Jul 5 2005, 01:48 AM)......   Jul 5 2005, 02:38 AM
- - BruceMoomaw   To Ted: both the HRI and MRI images were multispec...   Jul 5 2005, 02:40 AM
|- - MiniTES   QUOTE (BruceMoomaw @ Jul 5 2005, 02:40 AM)To ...   Jul 5 2005, 02:46 AM
|- - MiniTES   I also think NASA could have milked the publicity ...   Jul 5 2005, 03:07 AM
- - BruceMoomaw   To "Mini-TES": actually, your second sou...   Jul 5 2005, 04:19 AM
- - BruceMoomaw   As for an extended mission to a second comet; I ca...   Jul 5 2005, 04:21 AM
- - BruceMoomaw   And as for the impact being precisely on July 4 (w...   Jul 5 2005, 04:29 AM
- - BruceMoomaw   And here, finally, is the only additional data I w...   Jul 5 2005, 05:14 AM
- - BruceMoomaw   And here's a third one, which is useful in bei...   Jul 5 2005, 05:23 AM
- - slinted   Bruce: The pds site with the calibration data has...   Jul 5 2005, 05:59 AM
- - BruceMoomaw   Splendid! Thanks.   Jul 5 2005, 03:59 PM
- - Tman   Maybe you want to get a deeper look at the impact ...   Jul 5 2005, 05:02 PM
- - alan   What small mound?   Jul 5 2005, 05:17 PM
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