It’s confirmed: Dawn has entered orbit around the asteroid Vesta!
The spacecraft, which launched in September 2007, has been steadily approaching the giant asteroid for several months. Its mission is to orbit Vesta for a year, studying its surface and composition, and then push off toward the even larger asteroid Ceres. Actually classified as a dwarf planet, Ceres is the most massive body in the main asteroid belt.
While it was planned that Dawn would establish orbit on Saturday night, since Vesta’s mass is not precisely known and Dawn’s antenna was not oriented toward Earth at the time, mission scientists did not have confirmation of orbit until this morning.
The time of orbit insertion was 04:47 UTC on July 16 (9:47 p.m. PDT July 15.)
“Today, we celebrate an incredible exploration milestone as a spacecraft enters orbit around an object in the main asteroid belt for the first time. Dawn’s study of the asteroid Vesta marks a major scientific accomplishment and also points the way to the future destinations where people will travel in the coming years. President Obama has directed NASA to send astronauts to an asteroid by 2025, and Dawn is gathering crucial data that will inform that mission.”
– NASA Administrator Charles Bolden
We have been seeing progressively detailed images of Vesta coming in as Dawn approached over the past couple of months – the one shown above is the most recent one, received on July 9. It will be exciting to see the next set taken from orbit!
Dawn is the first spacecraft planned to orbit two different worlds beyond Earth.
Follow Dawn’s progress on the mission site here.
ADDED 7/18: See the first image of Vesta from orbit!
Lights in the Dark 
So cool!
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I’m extremely excited about this mission, as Vesta is such an early artifact of our Solar System when it was in its infancy. Though only a few hundred miles wide it had enough radioactive heating to differentiate and have volcanic eruptions during its first few millions of years.
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