You can view this 37 second Youtube movie here:
20 navigation images, pictures, or pics are looped 15 times as we see a quarter-rotation of Vesta. The largest crater (or ‘Feature B’ – we aren’t sure yet if it is a crater) is 60 miles across; Vesta’s diameter is 500 kilometers, or 300 miles.
The Dawn homepage has all the information. http://dawn.jpl.nasa.gov/
Dawn has traveled in interplanetary cruise mode for nearly three and three-quarters years since its launch Sept 27th, 2007; over 2.2 years of that has been powered ion-drive flight, greatly expanding our experience with these efficient engines to beyond 20,000 hours. Here is the powered-trajectory Timeline, with green sections for when one of the thrusters was on; there are three Xenon-ion thruster engines, that are used one at a time in a rotation schedule that averages out the wear on each engine.
Humanity is 200,000 kilometers from going into high initial mapping polar ‘survey orbit’ around the Main Belt’s second largest rock in August; Vesta is a solid nickel-iron asteroid, compared to Ceres’ frozen interior ocean.
Dawn Mission Chief Engineer Dr. Marc Rayman explains in his May 27th, 2011 Dawn Journal entry (although it is dated 2010 mistakenly in the actual entry): ”In survey orbit, the probe will be about 2700 kilometers (1700 miles) above the surface.”
Dawn has been decelerating relative to Vesta for the last 70 days, as it completes reducing relative velocity from a thousand mph down to a few mph over the last 100 days of ion-thrusting and over 950 total days of powered flight. Current velocity is 320 mph, 0.14 kph, and current range is 210,000 kilometers or 320,000 miles, with 30 days to go before arrival in Vesta’s gravity field on approximately July 16th.
[Update - an image from June 14th, two weeks closer, 265,000 kilometers from Vesta.]
The Dawn spacecraft and Vesta are traveling at 20 kilometers per second or 46,000 miles per hour relative to our Sun.
(Update June 26th – a June 20th image of Vesta rock.)
(Update July 1st, 2011) Image of Vesta from 150,000 kilometers, taken June 24th.
A July 1st photo, released July 7th.
Update July 14th – a new image from July 9th.
And Dawn also arrived at the International Spaceflight Museum. http://spindriftisland.wordpress.com/2011/06/23/dawn-asteroid-spacecraft-arrives-in-spaceport-alpha/
Dawn is featured at nature.com