When is the closest Itokawa flyby, and how far?

... half a million kilometers ...

Possibly a silly question, but at what inclination is this reference orbit? Wondering if they intend to (or even can) try for a polar/near-polar for full mapping.

We have constraints on the orbit we want to achieve based on the plans for acquiring and returning the data, but the details will depend on Vesta's gravity field and higher order gravity terms. So I hope you understand the 3003 x 2994 km orbit is just our current design. As I wrote in my latest Dawn Journal, we are beginning the detailed sequence design, and this is the reference orbit we use, but we are making the design tolerant to significant changes that will be dictated by what we find there. Planning for orbital operations at a massive body with a highly uncertain gravity field is very complicated.

That first orbit is called "survey orbit." The first ~ 5 days we are there will be used to tweak the sequences based on the actual orbit, updates to instrument parameters (e.g., integration times based on data acquired during approach), etc.

With our current design, the next science orbit will be at a radius of 950 km, and the third and lowest science orbit will be at a radius of about 460 km. Of course, we will not proceed from one orbit to the next without verifying we can do so safely, but unless we discover a problem, we will not change our plans once we are at Vesta. We will not choose to go to a lower orbit (apart, again, from what is needed based on the actual gravity field).

We have no concern about accidental impact with Vesta, even in the lowest orbit. The choice of the lowest radius is a trade-off between the need to go low for the benefit of GRaND on the one hand vs. the time required to travel there and the difficulty of operating so deep in the gravity field. When we are thrusting to low orbits, we are not acquiring the highest quality science data, and at some point it simply isn’t worth the time to continue flying down rather than devoting the time to getting the nuclear spectra. We have a lot to learn about the field, and while the risk of crashing is truly negligible, we still can get a very wild ride. Moreover, with our very large solar arrays, accommodating the gravity gradient torque at low altitude will be a challenge.

We can escape from any orbit we can fly to. The total delta-v for Vesta operations is a very small fraction of the flight system’s total capability. We spiral down, and then we spiral out!

So Peridemeter and apodemeter, perhaps.

Do these numbers represent the distance from the center of Vesta, or the overall size of the orbit?

Yes - but does Canberra have a steel Loch Ness Monster sticking out of a dry lake bed?

...at its closest encounter, on Mars 3 the probe will ..."

This link was posted in this thread earlier today:
http://www.mpi-hd.mpg.de/cassini/xxm/SM-7/SM-7_all.txt

I use ftp://naif.jpl.nasa.gov/pub/naif/CASSINI/...09248_17265.bsp

From that p.o.v. - looks like they can get a Mars-Earth 2-shot! Perhaps "cruise mode" doesn't let her wake up for these Kodak moments, though.

And thanks dmuller for that timeline. I'd not seen it before.

... Phoenix tried to walk south for the winter ...