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NASA Dawn Asteroid Mission Told to "Stand Back Up", Reinstated!
mchan
post Mar 28 2006, 10:39 PM
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QUOTE (Marz @ Mar 28 2006, 02:01 PM) *
3. aside from visual clues, are there any instruments on Dawn that can determine if there is a subsurface ocean on Dawn?


If the Dawn development team can't determine whether there is a subsurface ocean on Dawn, then the mission is doomed! smile.gif
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Guest_AlexBlackwell_*
post Mar 28 2006, 10:55 PM
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QUOTE (Marz @ Mar 28 2006, 10:01 PM) *
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?

Of course the magnetometer and, to a lesser extent, the laser altimeter, both dropped during the descope, would have addressed this. As is stands now, the best bet for determining the internal structures of Ceres and Vesta, and possibly detecting a putative internal ocean, is by the Dawn radio science experiment. Alex Konopliv of JPL and his colleagues hope that this experiment can return data resulting in 12 degree or higher global gravity field solutions, determination of principal axes, bulk density, etc., thereby placing constraints on the asteroids' internal structures. Whether this is enough to determine the existence of an internal ocean (e.g., by getting a good value for the asteroids' Love numbers) is unclear to me.

This post has been edited by AlexBlackwell: Mar 28 2006, 10:59 PM
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JRehling
post Mar 28 2006, 11:24 PM
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QUOTE (elakdawalla @ Mar 28 2006, 02:08 PM) *
Colleen Hartman said yesterday that the arrival dates were not changed by the one-year launch delay.

--Emily


Well, then, regardless of what happens with Dawn, the team behind it ought to consider opening an airline.


QUOTE (mchan @ Mar 28 2006, 02:39 PM) *
If the Dawn development team can't determine whether there is a subsurface ocean on Dawn, then the mission is doomed! smile.gif


The plan to include an ocean on Dawn has been scrubbed due to mass considerations.
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ElkGroveDan
post Mar 28 2006, 11:39 PM
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QUOTE (JRehling @ Mar 28 2006, 11:24 PM) *
The plan to include an ocean on Dawn has been scrubbed due to mass considerations.

My sources tell me there were corrosion issues as well.


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mars loon
post Mar 29 2006, 12:47 AM
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QUOTE (dvandorn @ Mar 28 2006, 07:58 AM) *
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


ah you beat me to this, My title was "DAWN reborn"

a new thread was overdue

sadly its too late for the magnetometer for technical reasons

on the budget,

many other recent missions, including our beloved rovers, NH, DI, MESSENGER,etc, have been far more overbudget. DAWN has been much closer to the target and the stand down added to the overrun


fortuneately due to the use of ion propulsion, there is a wide launch window extending to at least Oct 2007 and there is no delay in arrival to Ceres and Vesta.
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dvandorn
post Mar 29 2006, 02:26 AM
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QUOTE (JRehling @ Mar 28 2006, 05:24 PM) *
The plan to include an ocean on Dawn has been scrubbed due to mass considerations.

Awww... what if they descoped it? Just included a small sea on Dawn? That might work...

blink.gif

-the other Doug


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punkboi
post Mar 29 2006, 04:24 AM
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All that matters is... The 'Send your name to the Asteroid Belt' feature has been reinstated on the Dawn website biggrin.gif


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nprev
post Mar 29 2006, 06:40 AM
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You know, all these "Dawn ocean" jokes are a bit salty for my taste...in fact, they tide my patience! rolleyes.gif

Okay, I await a wave of criticism for that egregious flotsam... well, perhaps "jetsam" is more apropos due to Dawn's selected means of propulsion...tongue.gif


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Guest_Myran_*
post Mar 29 2006, 11:34 AM
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Ok great its back on track.
And no more ocean jokes? Ok I got a most serious question then.

QUOTE
punkboi said: The 'Send your name to the Asteroid Belt' feature has been reinstated on the Dawn website.


I did send my spouse to Mars on one of the Mer rovers, so now Dawn will fly I might consider sending myself there instead.
But the distance between Mars and the Asteroid belt isnt that far.
So I worry somewhat, if this will still be within yelling distance? laugh.gif
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Bjorn Jonsson
post Mar 29 2006, 12:48 PM
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QUOTE (mars loon @ Mar 29 2006, 12:47 AM) *
on the budget,

many other recent missions, including our beloved rovers, NH, DI, MESSENGER,etc, have been far more overbudget. DAWN has been much closer to the target and the stand down added to the overrun
fortuneately due to the use of ion propulsion, there is a wide launch window extending to at least Oct 2007 and there is no delay in arrival to Ceres and Vesta.
AFAIK NH was on budget - the others were not.

Hopefully this near-cancellation will serve as a clear warning to future Discovery proposers. Otherwise the way to get a mission flown is going to be to purposefully underestimate costs, include lots of instruments when proposing a mission and once it's approved and spacecraft construction has started a few instruments can be dropped and NASA informed that "oops, we need more $$". If this happens the reinstatement of Dawn is actually bad news. So overall I guess I'm happy that Dawn has been reinstated - but happy with some reservations.
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antoniseb
post Mar 29 2006, 01:45 PM
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QUOTE (dvandorn @ Mar 28 2006, 09:26 PM) *
Awww... what if they descoped it? Just included a small sea on Dawn?


I missed this thing getting started but is this a reference to the Ulysses mission, and Dawn and her fingertips of Rose igniting the clouds on the broad back of the wine dark sea?
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Bob Shaw
post Mar 29 2006, 02:21 PM
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QUOTE (antoniseb @ Mar 29 2006, 02:45 PM) *
I missed this thing getting started but is this a reference to the Ulysses mission, and Dawn and her fingertips of Rose igniting the clouds on the broad back of the wine dark sea?


No.

Bob Shaw


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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 Mar 29 2006, 06:52 PM
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There's a great deal on this subject scattered around in various places (including both the official website and a lot of recent conference abstracts). Once again, as soon as I get the chance (I'm trying to do several things at once), I'll try to dig up the best summaries for you.
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Guest_AlexBlackwell_*
post Mar 29 2006, 07:04 PM
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QUOTE (The Messenger @ Mar 29 2006, 04:08 PM) *
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

A couple of slightly outdated (from an instrument standpoint) references are "Dawn: A Journey In Space and Time" by Russell et al. and "DAWN: A JOURNEY TO THE BEGINNING OF THE SOLAR SYSTEM" by Russell et al.

If you have access to Planetary and Space Science, then a slightly more detailed mission description can be found here.

I also mentioned a recent Dawn-related article in Eos.

This post has been edited by AlexBlackwell: Mar 29 2006, 07:04 PM
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