Dawn spacecraft beams back new images of asteroid

[December 22, 2011]  LOS ANGELES (AP) -- NASA's Dawn spacecraft has been a fervent photographer, snapping more than 10,000 pictures of the asteroid Vesta since it slipped into orbit around the giant space rock last summer.

The views were taken from a distance away -- until now. On Wednesday, the space agency released new images of the hummocky surface as Dawn circled from an average altitude of 130 miles above the surface -- the closest it'll get.

From this low orbit, scientists can count numerous small impact craters and see textured grooves and outcrops in sharp detail.

"We're totally thrilled with the data we're getting. It seems to get better," said mission deputy principal investigator Carol Raymond of the NASA Jet Propulsion Laboratory, which manages the $466 million mission.

By inching this close to Vesta, Dawn will use other instruments to measure the gravity field and determine its chemical makeup to better understand its origins.

Dawn will spend the next 2 1/2 months at the current altitude before moving higher to take another round of pictures. By that time, the sun will hit Vesta at a different angle and illuminate sections of the northern hemisphere that had been shrouded earlier.

About the length of Arizona with a huge crater at its south pole, Vesta is the second largest body residing in the asteroid belt between Mars and Jupiter. Asteroids are leftovers from the solar system's birth some 4.5 billion years ago and studying these bodies could offer clues about how rocky planets like Earth formed.

Previous spacecraft have visited smaller asteroids before, but this is the first trip to Vesta.

Powered by ion propulsion, Dawn began orbiting Vesta in July after a 1.7 billion-mile cruise. It will depart Vesta next summer and will fly to an even bigger asteroid, Ceres, where it will arrive in 2015.

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Online:

Dawn mission: http://dawn.jpl.nasa.gov/

[Associated Press; By ALICIA CHANG]

Follow Alicia Chang at http://twitter.com/SciWriAlicia.

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