Dawn Cruise Options

[tedstryk]

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.

Ted

[elakdawalla]

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

[JTN]

(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.

[Holder of the Tw...]

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.

[ugordan]

deflection of the solar wind by a field might have prevented weathering

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

[Holder of the Tw...]

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.

[punkboi]

New Dawn journal up:

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

[peter59]

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

[peter59]

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.

[Stu]

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...

[Greg Hullender]

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

[Holder of the Tw...]

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 ...

[mps]

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

[punkboi]

New Dawn journal up:

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

[dmuller]

Pre-Dawn: The French-Soviet VESTA mission

I noticed the following paragraph in the above article:

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?