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Dawn Cruise
tedstryk
post Jan 9 2008, 11:53 AM
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That is still 7 million miles, but it could be done, at least as a test. It also flies by a really big object in February 2009. mars.gif

Ted


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elakdawalla
post Feb 1 2008, 07:28 PM
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The latest Dawn Journal is now up at JPL and TPS websites. In it, Marc reports that Dawn did go into safe mode on January 14, 2008, the same day as the MESSENGER flyby and when Ulysses went haywire, but Marc told me that the Dawn safing at least had nothing to do with any of the other drama in the solar system; it was a routine, well-understood event, and the spacecraft is fine.

--Emily


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JTN
post Feb 10 2008, 09:17 PM
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(I'm not normally into fields'n'particles, so forgive my ignorance...)
So, we lost the magnetometer. Is there any way, from science or engineering data, that we'll be able to tell anything at all about the magnetic environment of Ceres/Vesta? Not quantitative, just enough to spot Mercury-level surprises.
I know they don't put those awkward booms on spacecraft for the fun of it... just asking.
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Holder of the Tw...
post Feb 14 2008, 07:28 PM
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In a word, no.

If Vesta appears unusually bright, it could be guessed that deflection of the solar wind by a field might have prevented weathering, at least over a significant portion of past history. If gravity data indicates a very dense core for Vesta, that would also be an indication that a magnetic field is more likely, but won't tell you anything about whether it is really there. Any realistic value for what you could expect at Vesta will not affect high energy cosmics rays very much, those which provide part of the signature for GLAST.

For Ceres, it was speculated that salty underground water reservoirs might have a magnetic signature, like they do on Ganymede. If they are there, and they do, then there is no way now for DAWN to know about it.
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ugordan
post Feb 14 2008, 07:31 PM
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QUOTE (Holder of the Two Leashes @ Feb 14 2008, 08:28 PM) *
deflection of the solar wind by a field might have prevented weathering

Isn't the majority of space weathering related to micrometeoroid impacts?


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Holder of the Tw...
post Feb 14 2008, 07:51 PM
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The weathering being referred to here is the general darkening of an airless surface by the implantation of solar wind particles. Local areas of relatively high magnetic strength on the moon are lighter colored than their surroundings because they prevent this weathering.

But you make a good point. Vesta might have more gardening from impacts, since it is in the main belt. That could lighten up the surface, too. Which might make it even harder to guess about the cause.

Edit - Wait, wait. Sorry. You were talking about micrometeorites. Yes, they do darken the surface. I really don't know by what proportion. However, if you look at a picture of Reiner Gamma on the moon, you can see what a difference a magnetic shield can make.
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punkboi
post Mar 5 2008, 02:09 AM
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New Dawn journal up:

http://dawn.jpl.nasa.gov/mission/journal_2_29_08.asp


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peter59
post Mar 20 2008, 04:34 PM
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I nearly forgot about these cancelled missions.

Pre-Dawn: The French-Soviet VESTA mission

Very interesting three proposed trajectory for two spacecrafts.

Trajectory 1:
-launch from Earth
-Mars gravity assist
-flyby of 2335 James (a 10 km X-type asteroid) (an Amor-asteroid)
-Mars gravity assist
-109 Felicitas (C-type, 76 km)
-739 Mandeville (EMP(?) type, 110 km)
-4 Vesta (V-type, or Vestoid. Has a diameter of 570 km) flyby with 3.5 km/s. A penetrator is released.
Total delta-v: 450 m/s

Trajectory 2:
-launch from Earth
-Mars gravity assist
-flyby of the P/Tritton short period comet
-Mars gravity assist
-2087 Kochera (30 km?)
-1 Ceres (flyby & releasing a penetrator)
Total delta-v: 1150 m/s

Trajectory 3:
-launch from Earth
-Mars gravity assist
-1204 Renzia (10 km?) (an Amor-asteroid)
-Mars gravity assist
-435 Ella (U type, 30 km)
-46 Hestia (F type, 165 km)
-135 Hertha (M type, 80 km)
Total delta-v: 350 m/s


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peter59
post Apr 1 2008, 03:38 PM
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Dawn Completes Another Month of Thrusting
March 31, 2008
Dawn thrust with its ion propulsion system for most of March, stopping once each week to point its main antenna to Earth. Almost 96% of the month was devoted to thrusting.


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Stu
post Apr 1 2008, 04:11 PM
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QUOTE (peter59 @ Apr 1 2008, 04:38 PM) *
Dawn Completes Another Month of Thrusting
March 31, 2008


What is this, "Carry On Spaceflight"?!?!?! I could swear I heard Sid James laughing when I read that title... tongue.gif


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Greg Hullender
post Apr 30 2008, 04:01 AM
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I just noticed that Dawn has substantially upgraded their "Where is Dawn" page.

http://www.dawn-mission.org/mission/live_shots.asp

Now I have something to keep me entertained for the next 1213 days. :-)

--Greg
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Holder of the Tw...
post May 1 2008, 04:26 PM
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Yes, the diagrams are much better now, especially compared to the earlier monochome ones where you could barely tell the different orbits apart.

And ... the latest monthly thrusting report.

April 22

Carry on ... smile.gif
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mps
post May 30 2008, 11:46 AM
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Meanwhile somewhere on the vicinity of Mars...

Dawn Journal, May 27

quote: be sure to visit the cool new feature "Where is Dawn Now?" at http://dawn.jpl.nasa.gov/mission/live_shots.asp. The site includes depictions not only of the craft's trajectory and location but also of its attitude
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punkboi
post Jun 30 2008, 03:17 AM
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New Dawn journal up:

http://dawn.jpl.nasa.gov/mission/journal_6_26_08.asp


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dmuller
post Jun 30 2008, 06:41 AM
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QUOTE (peter59 @ Mar 21 2008, 02:34 AM) *


I noticed the following paragraph in the above article:
QUOTE
I've heard it's not ruled out that Dawn will be directed to rendezvous with 2 Pallas (for a slow flyby) in 2018, after the main mission at Vesta and Ceres is completed and enough fuel is left.

Is that possibly still on the cards?


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