[X] My Assistant

[Guest_BruceMoomaw_*]

I just caught this intriguing little note in a news release from the U. of Chicago on Stardust sample analysis.

http://www.spaceflightnow.com/news/n0602/20stardust/ :

" 'The Stardust spacecraft, meanwhile, may someday see further cometary action. "Stardust is still very healthy and has fuel left over,' [Thanasis] Economou said. 'After dropping the Space Return Canister, the spacecraft was diverted from entering the Earth's atmosphere and placed in an orbit around the sun that could bring it to another comet in February 2011.' "

Hmmm. Nice news, if true. Anyone have any idea which short-period comet this could be?



Meanwhile, another article on the first preliminary results from the dust analysis seems to show a surprise: a lack of hydrated silicates.

http://www.space.com/scienceastronomy/0602...ust_update.html :

"While the samples appear to lack indicators of water, they do contain sulfides, a key component to life...

"The early results reveal that the 4.5 billion-year-old comet contains iron, sulfides, glassy materials, olivine, and what the scientists termed potentially interesting isotopic traces. These believe that these materials were also available during the formation of other objects in our solar system...

" 'We're confident that the things coming out [of Comet Wild 2] are the same as those that went in,' Brownlee told SPACE.com. 'We believe that we collected the most pristine samples of a comet, those that have never been warmed.'

"While further analysis of Tempel 1 revealed water ice on its surface, so far no evidence of water has been detected in the particles. The other sign of water would be the presence of hydrated silicates, which were present in Tempel 1, Brownlee said; but so far none of these have been found in the Stardust samples."

Now, what does THAT signify? Could the particles have been dehydrated by frictional heat when they plowed through the aerogel? But surely in that case they would still show clear structural and mineralogical evidence of having been water-modified?

[Guest_BruceMoomaw_*]

It's possible that they may be hoping to fly Stardust by none other than Tempel 1, at its next perihelion -- which turns out to be in Feb. 2011! Such comparative studies of it by two spacecraft with different instruments -- perhaps even including an attempt by Stardust to photograph the Deep Impact crater -- would obviously be useful.

[ugordan]

Is it even possible for Stardust to be slinghshot towards the comet by Earth? There's only so much delta-V a gravity assist can provide.
Note that even if Stardust were redirected to fly by Tempel 1, there's only about a 50% chance it would see the crater when it's facing the S/C during the closest approach.
It would be neat if it were able to see it, though - "Stardust called up once again to do what Deep Impact was supposed to do in the first place..."

[Guest_BruceMoomaw_*]

I'm contacting Brownlee to see if this is indeed what they have in mind. Keep in mind that at this point they know the comet's speed and tilt of rotation pretty well, and could probably carry out a final midcourse correction to maximize the chances that the D.I. impact crater was on the side of the comet which Stardust was flying past.

[edstrick]

General observation: Comet dust is probably a transcendentally heterogeneous mix from different sources with a few sources of material dominating and others much scarcer. If -- as appears probable in small comets -- there was never internal melting, the materials are likely to be in extreme chemical dis-equilibrium.

One thing very unclear theoretically and being hinted at observationally is that the eroded comet surface shows a comples accretional history, quite likely with different materials accreting at different times, or at least different mixes of material. The presence of water-ice-rich exposures does little to suggest that that water has ever been melted or even warm enough to do vapor transport over the age of the solar system... or recently, or when the comet was accreting. Yet there could have been.

That's the sort of GEOLOGY, even if the term is linquisticaly a disaster, that the Euro orbiter will really be able to tackle.

[antoniseb]

It's possible that they may be hoping to fly Stardust by none other than Tempel 1, at its next perihelion

That would be very interesting. I hope it's possible.

[Guest_BruceMoomaw_*]

This just in: that IS what they're seriously considering for a Stardust extended mission:
http://www.spaceref.com/news/viewnews.html?id=1103

(I coudn't find anyone who knew anything about it at the Europa Focus Group meeting, and Don Brownlee never replied to my E-mail. According to Av. Week, they've been trying to keep this scheme under wraps.)

[Orlin Denkov]

It's possible that they may be hoping to fly Stardust by none other than Tempel 1, at its next perihelion -- which turns out to be in Feb. 2011! Such comparative studies of it by two spacecraft with different instruments -- perhaps even including an attempt by Stardust to photograph the Deep Impact crater -- would obviously be useful.

In the light of today's anouncement - I'm absolutely amazed from that precise supposition, made two months ago
I was reading carefully the article at the AviationNow, but I didn't uderstand the reasons for such a secrecy.
In any case it would be very important new target. Let's hope that they'll find the budget needed for the extansion of the Stardust mission.

[deglr6328]

Can we calculate the flyby velocity for a 2010 encounter?

[collectSPACE]

(According to Av. Week, they've been trying to keep this scheme under wraps.)

In January, Tom Duxbury spoke of the idea in an interview with John McGauley, albeit it was only a brief mention as the focus of his questions were on the future of the return capsule.

[Guest_BruceMoomaw_*]

In January, Tom Duxbury spoke of the idea in an interview with John McGauley, albeit it was only a brief mention as the focus of his questions were on the future of the return capsule.

Ah. I missed that one.

[Guest_BruceMoomaw_*]

More on this plan at http://www.newscientistspace.com/article/d...-revisited.html . (It is called -- I kid you not -- "ScarQuest".)

[ElkGroveDan]

More on this plan at http://www.newscientistspace.com/article/d...-revisited.html . (It is called -- I kid you not -- "ScarQuest".)

Veverka estimates that ScarQuest will cost between $20 million and $30 million.

Can someone give me rough pencil outline as to how this mission could reach $30 miilion in costs? Would it not just be man hours and DSN (or some other big ears) tracking time?

[Guest_AlexBlackwell_*]

Can someone give me rough pencil outline as to how this mission could reach $30 miilion in costs? Would it not just be man hours and DSN (or some other big ears) tracking time?

Without access to their cost breakdown data, we can do no more than speculate. However, the average person would be surprised to see how much personnel costs (i.e., "man hours") and DSN antenna time can amount to in a typical proposal, especially under the "full cost accounting" methodology that NASA requires proposers to utilize. ~$30 million for a Discovery MOO does not surprise me in the slightest.

EDIT: I should have added that the "~$30 million" figure almost certainly includes the NASA-mandated cost reserves that others (e.g., Dawn) have complained about.

This post has been edited by AlexBlackwell: Mar 22 2006, 01:37 AM

[Phil Stooke]

I'm surprised that mission planners think they can predict when the impact crater would be illuminated and facing the camera during the flyby. I would not have expected that the rotation rate was known well enough to know the nucleus orientation at a specific time five years from now. I'm all in favour of a new flyby but as a cartographer I'd rather see the other side!

Phil