One month to Vesta rock's Dawn orbit - 1st spin movie

Vesta from Dawn spacecraft July 9th 2011 41,000 km

NASA’s solar-electric ion-drive Dawn spacecraft is in its final three month approach phase to the second largest Main Belt asteroid, Vesta.

NASA Dawn probe sends first time-lapse rotation movie of Vesta

You can view this 37 second Youtube movie here:

http://www.youtube.com/watch?v=elel_HBHSV0

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.

 

Vesta Dawn powered trajectory chart. Green sections of Dawn trajectory are powered flight segments.

 

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.

http://en.wikipedia.org/wiki/4_Vesta

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.”

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

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.]

Vesta from Dawn 061411 quarter-million kilometers away

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.)

Vesta From Dawn Spacecraft - June 20th, 2011

(Update July 1st, 2011) Image of Vesta from 150,000 kilometers, taken June 24th.

Image of Vesta from 150,000 kilometers, taken June 24th.

A July 1st photo, released July 7th.

Vesta Dawn spacecraft image from 100,000 kilometers July 1st, 2011

Update July 14th – a new image from July 9th.

Vesta from Dawn spacecraft July 9th 2011 41,000 km

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
http://www.nature.com/news/2011/110713/full/475147a.html

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Tags: asteroid, Dawn, Dawn Journal, Dr Marc Rayman, ion-drive, Main Belt, NASA, powered flight, powered trajectory, space exploration, spacecraft, Vesta