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NASA Dawn Asteroid Mission Told to "Stand Back Up", Reinstated!
dvandorn
post Mar 28 2006, 07:58 AM
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Just 'cause I said I would... biggrin.gif biggrin.gif biggrin.gif biggrin.gif biggrin.gif biggrin.gif

Hopefully, though, this whole episode has made its point -- NASA isn't afraid to tell overbudget missions to stand down.

I just *really* wish we could get the magnetometer back on the beastie, though...

-the other Doug


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J.J.
post Mar 28 2006, 04:27 PM
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^
The launch has been pushed back to July 2007. That's better than nothing, but time will tell if it stays in-budget.


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Marz
post Mar 28 2006, 10:01 PM
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QUOTE (J.J. @ Mar 28 2006, 10:27 AM) *
^
The launch has been pushed back to July 2007. That's better than nothing, but time will tell if it stays in-budget.


Oh, I have no complaints delaying launch a year, so long as it flies.

So does this mean we can just add 1 year to the arrival times?
(2012=Vesta and 2016=Ceres?)

Ugh... these mission timelines are so painful! I'm beginning to loathe the "efficiency" of ion propulsion. ph34r.gif

Other questions:
1. did the recent keck/hubble observations of Ceres place a size limit boundary on any possible moons?

2. are Vesta and Ceres expected to both have at least one moon? (seems like most main-belt 'roids have companions, right?)

3. aside from visual clues, are there any instruments on Dawn that can determine if there is a subsurface ocean on Ceres? Is this completely unlikely, without tidal heating... or has Enceledus taught us a sound lesson to expect the unexpected?

4. Is EVE simply a Dawn clone to visit Pallas and other big 'roids? Should a lander mission be in the works for Ceres (dare I say, sample return)?

5. any likelyhood of the Pentagon being told to "stand down" as we review their incredible cost overruns and in the meantime use that budget to fund EVE and Dawn's Early Flight? unsure.gif
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The Messenger
post Mar 29 2006, 04:08 PM
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QUOTE (Marz @ Mar 28 2006, 03:01 PM) *
Oh, I have no complaints delaying launch a year, so long as it flies.

So does this mean we can just add 1 year to the arrival times?
(2012=Vesta and 2016=Ceres?)
...

3. aside from visual clues, are there any instruments on Dawn that can determine if there is a subsurface ocean on Ceres? Is this completely unlikely, without tidal heating... or has Enceledus taught us a sound lesson to expect the unexpected?
...


Can somebody provide me with a good reference on the scientific objectives and why-fors? I don't dare Google "Dawn Love Numbers" wink.gif
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Guest_BruceMoomaw_*
post Apr 1 2006, 12:48 AM
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QUOTE (The Messenger @ Mar 29 2006, 04:08 PM) *
Can somebody provide me with a good reference on [Dawn's] scientific objectives and why-fors? I don't dare Google "Dawn Love Numbers" wink.gif


One of the references Alex provided -- "Dawn: A Journey in Space and Time" -- is absolutely terrific for that purpose ( http://www-geodyn.mit.edu/russell.dawn_space_time.pdf ). It's dated mid-2003, but is still up to date in practically every respect. (It was written at a time when Dawn still had its magnetometer, and of course the launch date has since been changed, presumably with detailed effects on the schedule and duration of orbital activities around Vesta and Ceres.) Alas, there is no reference to "Love numbers". I'm currently trying to accumulate information on just how likely it is that Ceres might have a subsurface liquid-water ocean, given that it undergoes almost no tidal heating. Apparently McCord and Sotin did a piece in the May 2005 "JGR-Planets" ( http://www.agu.org/pubs/crossref/2005/2004JE002244.shtml ) concluding that the heat from the radioisotopes in Ceres' rocky core were probably adequate to keep some of its ice layer liquid for about 2 billion years -- and if Ceres also has a significant amount of ammonia in its interior (there's one extremely tentative hint of possible ammoniated clays in its near-IR surface spectra), they say it might have a liquid-water layer to this day, but that the odds are against it.

Two notes about Russell's article:

(1) The table on page 41 lists some possible asteroid flyby targets for Dawn's mission as it was then planned. Three of them are tiny things only a few km across; the fourth was 197 Arete, 30 km wide. The distances by which Dawn would have missed them if it expended none of its ion-drive fuel for minor course corrections to make close flybys of them are listed in "Gm" -- presumably "gigameters", or "millions of km". But page 12 notes: "Because of the efficiency of SEP, the number of candidate flyby targets is expected to be large, with many opportunities for low-velocity encounters. Groundbased observations of these targets will be critical to a selection of targets on the basis of science return as opposed to simple dynamical convenience." Even with Dawn's fuel load reduced, we can still hope for a fair number of such flybys.

(2) The minimum "performance floor" version of the Dawn mission (pg. 13-14) called for it to orbit Vesta, but just to fly by one hydrated C-type asteroid similar in overall composition to Ceres -- perhaps the 100-km wide "50 Virginia". This confirms something I said earlier: where asteroids are concerned, size matters a lot less than composition. During the quarter-century in which I've been reading proposals for asteroid exploration, Vesta has always been right at the top of every list because of its unique composition, which seems to be right at the far end of the spectrum of asteroid differentiation levels. But, until Dawn came along, I had NEVER seen Ceres listed as any kind of high- or even medium-priority target, despite the fact that it's the unquestioned King of the Asteroid Belt -- the reason being simply that, compositionally, it was regarded as just one of a fairly large number of hydrated C-type asteroids. It was starting to look as though, by 2020, Ceres would be by far the biggest object in the Solar System anywhere this side of the Kuiper Belt to be unreconnoitered.
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Posts in this topic
- dvandorn   NASA Dawn Asteroid Mission Told to "Stand Back Up"   Mar 28 2006, 07:58 AM
- - Holder of the Two Leashes   Does anyone know how much it would cost to reinsta...   Mar 28 2006, 03:32 PM
|- - Marz   yee haw!! Has the mission timeline be...   Mar 28 2006, 04:15 PM
- - J.J.   ^ The launch has been pushed back to July 2007. T...   Mar 28 2006, 04:27 PM
|- - Marz   QUOTE (J.J. @ Mar 28 2006, 10:27 AM) ^ Th...   Mar 28 2006, 10:01 PM
|- - mchan   QUOTE (Marz @ Mar 28 2006, 02:01 PM) 3. a...   Mar 28 2006, 10:39 PM
|- - AlexBlackwell   QUOTE (Marz @ Mar 28 2006, 10:01 PM) 3. a...   Mar 28 2006, 10:55 PM
|- - The Messenger   QUOTE (Marz @ Mar 28 2006, 03:01 PM) Oh, ...   Mar 29 2006, 04:08 PM
|- - AlexBlackwell   QUOTE (The Messenger @ Mar 29 2006, 04:08...   Mar 29 2006, 07:04 PM
||- - SFJCody   Magnetometer or not, 2015 will put a significant c...   Mar 29 2006, 08:01 PM
||- - The Messenger   QUOTE (AlexBlackwell @ Mar 29 2006, 12:04...   Mar 29 2006, 08:05 PM
||- - AlexBlackwell   QUOTE (The Messenger @ Mar 29 2006, 08:05...   Mar 29 2006, 08:08 PM
||- - SFJCody   QUOTE (The Messenger @ Mar 29 2006, 09:05...   Mar 29 2006, 08:10 PM
|- - BruceMoomaw   QUOTE (The Messenger @ Mar 29 2006, 04:08...   Apr 1 2006, 12:48 AM
|- - AlexBlackwell   QUOTE (BruceMoomaw @ Apr 1 2006, 12:48 AM...   Apr 1 2006, 01:36 AM
|- - tedstryk   QUOTE (BruceMoomaw @ Apr 1 2006, 12:48 AM...   Apr 2 2006, 04:53 PM
- - AlexBlackwell   QUOTE (dvandorn @ Mar 28 2006, 07:58 AM) ...   Mar 28 2006, 04:49 PM
|- - SFJCody   QUOTE (AlexBlackwell @ Mar 28 2006, 05:49...   Mar 28 2006, 04:58 PM
||- - JRehling   QUOTE (SFJCody @ Mar 28 2006, 08:58 AM) I...   Mar 28 2006, 05:58 PM
|- - elakdawalla   QUOTE (AlexBlackwell @ Mar 28 2006, 08:49...   Mar 28 2006, 05:45 PM
|- - AlexBlackwell   QUOTE (elakdawalla @ Mar 28 2006, 05:45 P...   Mar 28 2006, 06:02 PM
- - gpurcell   http://dawn.jpl.nasa.gov/science/technology.asp S...   Mar 28 2006, 05:40 PM
- - peter59   I checked my calendar but it is not April Fool...   Mar 28 2006, 05:46 PM
- - BruceMoomaw   It is, I imagine, well too late to reinstall eithe...   Mar 28 2006, 08:11 PM
|- - AlexBlackwell   QUOTE (BruceMoomaw @ Mar 28 2006, 08:11 P...   Mar 28 2006, 09:30 PM
- - elakdawalla   Colleen Hartman said yesterday that the arrival da...   Mar 28 2006, 10:08 PM
|- - JRehling   QUOTE (elakdawalla @ Mar 28 2006, 02:08 P...   Mar 28 2006, 11:24 PM
|- - ElkGroveDan   QUOTE (JRehling @ Mar 28 2006, 11:24 PM) ...   Mar 28 2006, 11:39 PM
|- - dvandorn   QUOTE (JRehling @ Mar 28 2006, 05:24 PM) ...   Mar 29 2006, 02:26 AM
|- - antoniseb   QUOTE (dvandorn @ Mar 28 2006, 09:26 PM) ...   Mar 29 2006, 01:45 PM
|- - Bob Shaw   QUOTE (antoniseb @ Mar 29 2006, 02:45 PM)...   Mar 29 2006, 02:21 PM
- - mars loon   QUOTE (dvandorn @ Mar 28 2006, 07:58 AM) ...   Mar 29 2006, 12:47 AM
|- - Bjorn Jonsson   QUOTE (mars loon @ Mar 29 2006, 12:47 AM)...   Mar 29 2006, 12:48 PM
- - punkboi   All that matters is... The 'Send your name to ...   Mar 29 2006, 04:24 AM
- - nprev   You know, all these "Dawn ocean" jokes a...   Mar 29 2006, 06:40 AM
- - Myran   Ok great its back on track. And no more ocean joke...   Mar 29 2006, 11:34 AM
|- - dvandorn   QUOTE (Myran @ Mar 29 2006, 05:34 AM) ......   Mar 29 2006, 11:01 PM
- - BruceMoomaw   There's a great deal on this subject scattered...   Mar 29 2006, 06:52 PM
- - Mariner9   I second SFJCody's comment about a capstone ev...   Mar 29 2006, 08:45 PM
|- - SFJCody   QUOTE (Mariner9 @ Mar 29 2006, 09:45 PM) ...   Mar 29 2006, 09:51 PM
|- - JRehling   QUOTE (Mariner9 @ Mar 29 2006, 09:45 PM)W...   Mar 29 2006, 10:19 PM
- - BruceMoomaw   Actually, we still won't have done that. We h...   Mar 29 2006, 09:51 PM
- - Mariner9   Sigh. I considered putting in a caveate about th...   Mar 29 2006, 11:00 PM
- - BruceMoomaw   Actually, the Moomaw was just trying to point out ...   Mar 30 2006, 02:52 AM
|- - JRehling   I have a long-standing belief that I haven't h...   Mar 30 2006, 03:47 PM
- - Myran   QUOTE dvandorn said: in space, no one can hear you...   Mar 30 2006, 05:06 PM
|- - JRehling   QUOTE (Myran @ Mar 30 2006, 09:06 AM) Are...   Mar 30 2006, 05:12 PM
- - BruceMoomaw   One of the major mysteries of the belt is how Vest...   Mar 30 2006, 06:31 PM
- - Myran   QUOTE JRehling wrote: The total mass of the main b...   Mar 30 2006, 06:36 PM
|- - tedstryk   I think that it depends on how one defines samples...   Mar 30 2006, 08:39 PM
|- - JRehling   QUOTE (Myran @ Mar 30 2006, 10:36 AM) But...   Mar 30 2006, 11:39 PM
- - Mariner9   I remember in one of the earlier Discovery mission...   Mar 31 2006, 03:47 PM
|- - JRehling   QUOTE (Mariner9 @ Mar 31 2006, 07:47 AM) ...   Mar 31 2006, 05:47 PM
|- - Bob Shaw   QUOTE (JRehling @ Mar 31 2006, 06:47 PM) ...   Mar 31 2006, 10:57 PM
|- - David   Not me, but one thing occurs to me: aren't the...   Apr 1 2006, 12:06 AM
|- - JRehling   QUOTE (David @ Mar 31 2006, 04:06 PM) Not...   Apr 1 2006, 12:32 AM
- - BruceMoomaw   It's certainly an idea. One might even combin...   Mar 31 2006, 08:12 PM
- - BruceMoomaw   Oh, yes. Might be worth doing anyway, though, if ...   Apr 1 2006, 12:16 AM
- - BruceMoomaw   I've considered trying to look into the questi...   Apr 1 2006, 02:22 AM
- - BruceMoomaw   That, in turn returns us to the question I mention...   Apr 2 2006, 08:13 PM
|- - Bob Shaw   Bruce: 'Harder metal cores?' That's a...   Apr 2 2006, 08:57 PM
- - BruceMoomaw   As a matter of fact, the fact that a lot of the as...   Apr 2 2006, 11:34 PM
- - Bart   A new edition of the Dawn's Early Light newsle...   Apr 6 2006, 10:23 PM
|- - mchan   The newsletter notes what was posted earlier in th...   Apr 8 2006, 02:16 AM
- - gpurcell   Looks like they whacked the program managers from ...   Apr 7 2006, 04:23 PM
- - Marz   So Oct 31, 2007 is a scary date indeed! I...   Apr 9 2006, 02:58 PM
- - BruceMoomaw   Andy Dantzler just provided an "explanation...   Apr 11 2006, 08:37 PM
- - gpurcell   QUOTE The other thing is when you do overrun - if ...   Apr 11 2006, 10:38 PM
|- - BruceMoomaw   [quote name= quote in reply - removed [/quote] No...   Apr 12 2006, 12:05 AM
- - gpurcell   Well, if he can still get two new vehicles out of ...   Apr 12 2006, 03:07 PM
- - Analyst   What has been the problem with the Discovery 11 AO...   Apr 18 2006, 10:59 AM
|- - BruceMoomaw   QUOTE (Analyst @ Apr 18 2006, 10:59 AM) W...   Apr 18 2006, 09:48 PM
|- - ugordan   QUOTE (BruceMoomaw @ Apr 18 2006, 10:48 P...   Apr 20 2006, 09:31 AM
- - monitorlizard   Without trying to provoke anger, I think Dawn was ...   Apr 18 2006, 12:38 PM
|- - Bob Shaw   QUOTE (monitorlizard @ Apr 18 2006, 01:38...   Apr 18 2006, 01:12 PM
|- - tedstryk   QUOTE (monitorlizard @ Apr 18 2006, 12:38...   Apr 18 2006, 02:48 PM
- - Analyst   Thank you, Bruce.   Apr 20 2006, 08:00 AM
- - Analyst   I guess it's not rising but falling demand. A ...   Apr 20 2006, 03:17 PM
- - BruceMoomaw   "Analyst" is correct -- as the demand fo...   Apr 20 2006, 08:31 PM
|- - Bob Shaw   Bruce: SeaLaunch on Zenit-2. Bob Shaw   Apr 20 2006, 08:40 PM
|- - RNeuhaus   QUOTE (Bob Shaw @ Apr 20 2006, 03:40 PM) ...   Apr 22 2006, 02:19 AM
|- - tedstryk   [quote name='RNeuhaus' _quote in reply -re...   Apr 22 2006, 02:21 AM
- - djellison   Sea Launch is 5200kg to GTO Delta II Heavy - 2064 ...   Apr 20 2006, 10:36 PM
|- - Bob Shaw   QUOTE (djellison @ Apr 20 2006, 11:36 PM)...   Apr 21 2006, 07:43 PM
|- - Jim from NSF.com   QUOTE (Bob Shaw @ Apr 21 2006, 03:43 PM) ...   Apr 22 2006, 07:57 PM
- - edstrick   The europeans ran into the same "oops.... how...   Apr 21 2006, 10:40 AM
- - BruceMoomaw   Yeah, but most Solar System launches have limited ...   Apr 22 2006, 02:06 AM
- - remcook   zenit is the rocket model   Apr 22 2006, 03:46 PM
- - tty   How about Long March 2 - 3370 kg to GTO tty   Apr 22 2006, 05:13 PM
- - ljk4-1   Mark Rayman has created his first log of the renew...   Apr 27 2006, 01:54 PM
- - Rakhir   Dawn Team Looking Good For Launch Next Year http:...   Jun 1 2006, 08:38 AM
|- - Marz   QUOTE (Rakhir @ Jun 1 2006, 03:38 AM) Daw...   Jun 1 2006, 03:50 PM
- - PhilHorzempa   Some recently posted images on DAWN website showin...   Jun 29 2006, 03:43 AM
|- - punkboi   QUOTE (PhilHorzempa @ Jun 28 2006, 08:43 ...   Jun 29 2006, 05:42 PM
- - PhilHorzempa   There have been several very good photos of DAWN r...   Aug 1 2006, 03:38 AM
- - djellison   Is it really necessary to attach these images to t...   Aug 1 2006, 08:53 AM
- - punkboi   Last day to send your name to the asteroid belt is...   Sep 13 2006, 07:46 AM


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