HAMO, (aka High Altitude Mapping Orbit) Options

[Paolo]

12 presentations!

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

Curiously, first crater counts from lower resolution images of the south polar depression suggest surface model ages similar to ages for northern cratered regions, despite the highly deformed state of the south polar surface.

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

[Juramike]

And along a similar vein (!):

Color data suggests that the feature [the south polar basin] as a whole is more mafic than surrounding terrain.

Possible hypotheses for formation include impact and resulting faulting, fracturing and folding; endogenic activity such as upwelling or downwelling of a plume and subsequent structural disruption; or some combination of exogenic and endogenic processes. At the time of this abstract, the geologic map is consistent with any of these hypotheses.

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?)

[volcanopele]

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.

Reason for edit: Because Phil Made Fun of Me

[Phil Stooke]

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

Phil

(just kidding!)

[volcanopele]

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

[Phil Stooke]

Well, you're getting lots of experience!

Phil

[stevesliva]

I wouldn't mind if you called it Rheasliva.

It's got to be an impact crater, right? Not really? "Endogenic?" Would that be like the runaway radioactive-earth-birthing-the-moon hypothesis? Vesta just one day exploded like rotting fruit?

[Phil Stooke]

A little thing I've been playing with... the recently released map extended only to about 40 degrees north. I took the northern hemisphere and converted it to a pole-centred view. Many of the image releases including today's extend coverage into the north polar region, which I call 'Philstookia'. Here's the map so far.

Phil

[dilo]

In the last 5 days, Dawn didn't use his engine and remained in a slightly eccentric orbit (665x700 km height):

According to last Mission Status, this provisional orbit will allow to set precise orbital parameters and make final orbit adjustment during next week.

UPDATE: According to Dr Marc Rayman private communication, they are now acquiring "Doppler and range data (both to improve the orbit knowledge and to refine the gravity field), and then design, build, and execute a trajectory correction maneuver on Monday night and Tuesday night of next week."

[DFinfrock]

the north polar region, which I call 'Philstookia'.

Philstookia appears to be an immense "abyss".

[Greg Hullender]

In the last 5 days, Dawn didn't use his engine . . .

In English, a space probe (like Dawn) is always "she" never "he." So you should say "Dawn didn't use her engine."

Non povo explicare. :-) That's just how it is.

--Greg

[monty python]

Just looking at Phil's picture.

What if a rapidly spinning Vesta was hit by a huge body early in the asteroid belt formation?

Would you get spiral grooves and terrain jumbled at odd angles?

Brian

[tanjent]

Indeed, Vesta's midsection does look as if it has been worked on a lathe. But the rotational axis on an actual lathe is maintained by a mechanically rigid piece of machinery. For a pair of free-spinning celestial bodies, it is hard to see how they could maintain just the right distance for several revolutions so to gouge out the grooves without bouncing off, melting, breaking up, merging, etc. The sort of light, plowing, contact that monty is considering is a pretty unstable situation. That said, I don't have a better idea to explain how the grooves got there. I assume some common cause must operate on vesta, phobos, lutezia, maybe even iapetus, but most of the contending stories have holes in them. Let's keep working on it.

[bk_2]

I don't have a better idea to explain how the grooves got there. I assume some common cause must operate on vesta, phobos, lutezia, maybe even iapetus, but most of the contending stories have holes in them. Let's keep working on it.

If the grooves are not associated with the southern impact, though I find that hard to accept, and predate the modern surface, they must be very old, perhaps from it's formative period. The only mechanism I can propose for parallel grooves is the same one I raised in the case of Phobos viz, intersection with co-planar rings. If in it's formation, Vesta was in an elliptical orbit around a larger body with coplanar circular rings, it could have encountered planar rings edge-on at each periapsis. The global extent of these grooves would indicate that Vesta, unlike Phobos, was not tidally locked at the time.

[Explorer1]

Latest journal entry shows that Rheasilvia is indeed the official name of the south pole crater!