According to Dawn (who ought to know) the descent to the next mapping orbit is beginning now.

"NASA_Dawn NASA's Dawn Mission

I'm done with Survey science operations today!! Time for a several-week transfer down to High Altitude Mapping Orbit (HAMO)!!

20 hours ago"


Better pics on the way! Thanks, Dawn team, for the pictures so far. Will we learn of any preliminary nomenclature soon?

Phil

Marc Rayman's latest Dawn Journal on HAMO --

"...they have been able to detect variations in the gravity field that are due to the uneven distribution of mass within the protoplanet. With their improved charts of the waters around Vesta, they plotted the ship’s course, and it is now under sail. Thrusting with the ion propulsion system began on August 31 at 4:05 p.m. PDT, and this trip to the high altitude mapping orbit will take a month."

Hi Phil!
Nomenclature work has only just begun. we have been "surveying' the Survey data as it were, simply getting a feel for the geography. Once the coordinate system has been fixed, we will proceed with names. A list of names is ready to go, we just need to identify which features are priority for the first batch of names.
cheers
paul

Thanks, Paul.

Phil

Thanks for updates, Paul!
Here below the updated velocity/distance plots, current transfer orbit is clearly elliptical.
Click to view attachment

no problem. will try to be more informative as the mission goes on, but i get distracted easily . . .

btw, where are u getting that plot from? I should be monitoring it i suppose!

I made by myself using MYSTIC simulator info from JPL Dawn site. Obviously, not real-time data nor continuous coverage, if you have something better, pls give us!

First Message: Hello everybody

Answering dilo:
You can use SPICE data from NAIF: ftp://naif.jpl.nasa.gov/pub/naif/DAWN/kernels/
For example, I product this http://www.youtube.com/watch?v=qWZbcAKXu-s from theses data.
The problem is that you should have some (but little ) programming skill for using SPICE files.
But the good news is that the NAIF library (see upper node of link) is full of documentations and tools to learn and use it.

But maybe DrShank know a better way ?

not without doing some research into it . . .

Thanks Sarunia, not an easy task for me (unless someone wants to help on this).
For the moment, I'm still updating from simulator:
Click to view attachment

Great pictures recently - not from HAMO yet or even the descent to HAMO, but really giving a taste of what the surface will look like in the weeks to come.

http://dawn.jpl.nasa.gov/multimedia/imageo...=2011-September

I'm especially interested at the moment in this area from the Sept. 3 release:


Click to view attachment


Interesting bright patches on a darker surface.

Phil

Dare I say those lobate margins look like flow features? Fun to think about, anyway!

> I'm especially interested at the moment in this area from the Sept. 3 release:

And why does this crater have an eccentric fill on the floor?
What a peculiar little world.

The Dawn team could not agree more!

as far as those bright and dark splotches, we are scratching our heads too. they do not seem to have much relief at this resolution (we are
still at ~250 meters and will move to HAMO resolution very slowly) but each significant increase in resolution has forced us to rethink some of our previous conclusions! Vesta is not a simple world.

The eccentric fill may be a result of a local slope - the fill is horizontal, the crater's tilted. Of course, we need a proper shape model and interior mass distribution model to be sure, but that's my guess.

Phil

I considered this an, uh, occipital illusion, and briefly discounted a local slope phenomenon since this is not a grossly potato-shaped world, but the local slope phenomenon is likely the most tenable.

Still, ain't Kansas...

--Bill

Several of the recent images can be joined to make a rough mosaic - the first one (left end) in its raw form and the rest distorted to fit it, very uncontrolled.

Phil

Click to view attachment

Hi Phil,
First of all, great job at mosaicking. Second, I just would like to point out that the dark patch south east of the snowman (and including part of the middle crater) are the region formerly known as Olbers. This is the kind of surprises the Vesta holds for us.
We hope to see these mysteries resolved soon!
Regards

...again. (That's why I've been hooked on UMSF since Mariner 9...)

Never gets old, not a bit. We NEVER find what we expect, and of course that's why we go.

Latest picture of the day - an unusual hill:


http://dawn.jpl.nasa.gov/multimedia/imageo...p?date=20110908


But they don't say what's unusual about it, so I'm forced to offer my own theory. It resembles a whale - eye, mouth, fin, tail... head at the top. I think it's the whale from the Hitchhikers Guide to the Galaxy. Of course it could be something boring like a volcano!

Phil

Assuming the magma chamber is not uranium powered - what is the smallest body that can support a volcano?
Wouldn't Vesta be below that limit?

it could be a shadow of an unknown moon ...

A whale-shaped moon!

Vesta is well known for its basalt crust, as shown by spectroscopy and the meteorites thought to have come from Vesta. So volcanoes can't be ruled out. The idea of a minimum size for volcanoes may crumble in the face of evidence. That's what Dawn is all about.

Phil

Click to view attachment

Dawn is approaaching to final orbit through a complicate set of maneuvers:
Click to view attachment
Happy to see now precise distances indication on simulator (because we are under 1 thousand miles!):
Click to view attachment

A glimpse of Vesta in colour!
http://photojournal.jpl.nasa.gov/catalog/PIA14697

(Alongside a visual/infrared false-colour image of the same bit of terrain.)

I wonder where on Vesta this is.

And today picture resized 400% and gamma corection for "best look"
From TIFF.

Click to view attachment


Source:
http://photojournal.jpl.nasa.gov/catalog/PIA14698
http://dawn.jpl.nasa.gov/multimedia/imageo...p?date=20110911

More and more closer to final orbit...

Simulator didn't update images in the last 14 hours!
Do someone knows the reason?

Have you tried sending them a friendly email rather than post an angry face here?

Good suggestion, Dough (I was hoping someone here was informed, but direct contact is better).
I received a kind answer after only 7 minutes by Judy Counley (Dawn site webmaster) telling that the responsible for simulator is already working on the issue!

This picture is starting to show some very fine surface detail and texture. I can see why the science pros are tossing out some of their early hypotheses. There is more than enough weird stuff not like anything else seen to make me want to shut up theorizing until I've had a closer look.
Some of the topics for thought on the shaping of Vesta...
Extreme seismic phenomenon from South Pole impact. Contributor to Equatorial grooves? To smaller terrain shapes?
Extreme-but-transient electromagnetic phenomenon. (Impact, CME?)
Large structurally detailed albedo features relatively independent of surface terrain. Impacts of globs of stuff? Exposed dike/craton forms?
Ring collapse onto wobbly Vesta? Unlikely, with many ridge-groove areas non-great-circle. But if the impact sent out heavily-"rayed" debris, could it produce the right terrain on fast-rotating Vesta?

So many questions. More than before Dawn arrived...

Yes, we'ev got a lot of puzzle-pieces to fit and assemble. The duck-feet look like chicken-feet which are starting to look like talons...

--Bill

Many great new pics at the Photojournal today including this new map:

http://photojournal.jpl.nasa.gov/catalog/PIA14703

including a gridded version. The coordinate system does not match the old one derived from Hubble images, a point that is causing some controversy, but I have little doubt that this will become the official coordinate system eventually. Another image in the new set defines the prime meridian marker:

http://photojournal.jpl.nasa.gov/catalog/PIA14715



Phil

This is a montage of frames from the shape model rotation movie also included in this release.

Phil

Click to view attachment

Also cataloged here:
http://dawn.jpl.nasa.gov/multimedia/vesta_dawn_gallery.asp

It's amazing how there are some very distorted ancient basins in the more tropical latitudes. And perhaps another giant basin that creates a gap in the south polar crater "rim." And the grooves aren't equidistant from the center of the southern crater, are they?

Sharp eyes you have there! we have been discussing both aspects (ancient degraded craters, and the large "Giant basin" as you call it,
for several weeks. Vesta definitely has a history predating the large south polar basin.

http://www.dawn.mps.mpg.de/index.php?id=17...de9d31da5358ace


False color map of Vesta - very nice! It's not the full range of longitudes, only about 240 degrees long, and it doesn't register exactly with the recent base map (different projection), but it is interesting. This barely gets into the south polar depression at its southern edge.

Phil

Love it! Sooo cool! How about that massive chasma across the middle? (Blue material in false color)

Approximate fit to the previous map.

Phil

Click to view attachment

Could this be a basin?
Click to view attachment

It's clearly a basin. The trick is, what caused it? That wonderful south polar impact threw up a huge amount of ejecta, a fair portion of which would have fallen back to the surface in all sorts of interesting ways. Shaking from the impact doubtless created some interesting structures. Based on what we know so far, Vesta's going to be a tough (and tasty!) nut to crack.

I had an interesting and very pleasant communication with Dr. Marc Rayman; he explained me that, until few hours ago, Vesta distance reported in the Simulator was based on extrapolated values of distance from asteroid centre, not height. I corrected my database and now is clear that Dawn is very close to HAMO final orbit, both in terms of height and speed (685 km and 135 m/s):
Click to view attachment
update: in the bottom/left plot I changed potential energy (now represented with the correct negative sign) and I added total energy curve (kinetic+potential).

Hi Mike,
The blue material in the false color composite seems to be the ejecta blanket from the snowman crater(s). It is known to be remarkably dark and it was named in the past... Olbers Regio.
Cheers.

Yes! It's very interesting to overlay the Hubble compositional maps (in Li et al., Icarus 208 (2010) 238–251, for instance) over the new maps. Even quite small crater ejecta deposits line up very well. The two 'red' patches (false color) were clearly seen, but mapped as different things (Eucrite and weathered materials). No doubt we'll be getting team publications on this in due course.

Phil

In Universe Today is an interview with Prof. Chris Russell and Carol Raymond.

South pole impact feature has been officially named Rhea Silvia after the mother of Romulus and Remus, mthyical mother of the Vestal virgins.

Prof. Chris Russell
“We have set ourselves a target to gather everything we know about the south pole impact feature and expect to have a press release from what ever we conclude at the GSA (Geological Society of America) meeting on October 12. “We will tell the public what the options are.

“We do not have a good analog to Vesta anywhere else in the Solar System and we’ll be studying it very intently.”

Sorry for the long url...

http://www.universetoday.com/89093/rhea-si...her/#more-89093

Craig

GSA meeting 10/12/11... DAWN session

Dawn at Vesta: Initial Results from the Survey Orbit
http://gsa.confex.com/gsa/2011AM/finalprog...ssion_28729.htm

12 presentations!

Craig

abstract mostly do not reflect the results of the first weeks in orbit. but there are some exceptions.
I found this intriguing:



from http://gsa.confex.com/gsa/2011AM/finalprog...ract_198143.htm

And along a similar vein (!):





Both quotes from: http://gsa.confex.com/gsa/2011AM/finalprog...ract_196317.htm
Intriguing to think that it could be pure endogenic. (where could all that energy come from?)

It makes some sense. The reason you think everything outside of Rheasilvia is older is because of the plethora of little impact craters that saturate much of the rest of Vesta (except around the snowmen) that you just don't see in it. The age estimate from lower res images like uses craters larger than these little guys and for those you could make the argument that there really aren't that many more outside the big crater than outside.

Perhaps the saturated crater population are secondaries from the big giant impact which basically reset the cratering age of Vesta. Only those secondaries that fell outside the crater which shall not be named survived. The larger craters, like the snowmen, formed after it.

When you say Rheasilvia, do you mean Rheasilvia or just Rheasilvia?

Phil

(just kidding!)

Hey, I am just trying to get used to the name...