Dawn SpEcraft Captures Up-Close Imagery of Asteroid Vesta

The Dawn spacecraft is sending back some of the first full-frame images of the asteroid Vesta as it spirals towards the first of four science orbits around the asteroid.

The images, which were captured on July 24, were taken at a distance of 3,200 miles from Vesta and reveal some of the first surface details about the asteroid. They cover the entire asteroid, NASA said, because Vesta turns on its axis once every five hours and 20 minutes.

"Now that we are in orbit around one of the last unexplored worlds in the inner solar system, we can see that it's a unique and fascinating place," Marc Rayman, Dawn's chief engineer and mission manager at NASA's Jet Propulsion Laboratory, said in a statement.

The images were collected via Dawn's framing camera, but the spacecraft also includes a gamma ray and neutron detector, which uses 21 sensors to measure the energy of subatomic particles emitted by Vesta. An infrared mapping spectrometer will also measure the surface mineralogy of Vesta and Dawn's next target, the dwarf planet Ceres.
That first intensive science orbit, meanwhile, will begin August 11 at an altitude of 1,700 miles and provide in-depth analysis of Vesta.

"We have been calling Vesta the smallest terrestrial planet," said Chris Russell, Dawn's principal investigator at UCLA. "The latest imagery provides much justification for our expectations. They show that a variety of processes were once at work on the surface of Vesta and provide extensive evidence for Vesta's planetary aspirations."

Dawn successfully entered Vesta's orbit on July 16, and sent back the first images several days later. Engineers are still trying to determine the exact time Dawn entered Vesta's orbit, but are currently estimating it at 12:47am Eastern time.

Dawn will study Vesta for one year, gathering observations that NASA said will help scientists understand the earliest chapter of our solar system's history. Dawn will then depart for the dwarf planet Ceres in July 2012.

This milestone has been several years in the making; Dawn departed Earth in 2007 and when it completes its journey, it will become the first spacecraft to orbit two solar system destinations beyond Earth, NASA said.