Dawn Began Vesta Encounter Friday

NASA's Dawn spacecraft has begun a prolonged encounter with the asteroid Vesta, making the mission the first to enter orbit around a main-belt asteroid.

Vesta Asteroid From 26,000 Miles

The main asteroid belt lies between the orbits of Mars and Jupiter. Dawn will study Vesta for one year, and observations will help scientists understand the earliest chapter of our solar system's history.

As the spacecraft approached Vesta, surface details became more distinct, as seen in a recent image taken from a distance of about 26,000 miles.

Engineers have been subtly shaping Dawn's trajectory for years to match Vesta's orbit around the sun. Unlike other missions, where dramatic propulsive burns put spacecraft into orbit around a planet, Dawn eased up next to Vesta. Then the asteroid's gravity captured the spacecraft into orbit. However, until Dawn got close to Vesta and made accurate measurements, the asteroid's mass and gravity were only estimates. The Dawn team will refine the exact moment of orbit capture over the next few days.

Launched in September 2007, Dawn will depart for its second destination, the dwarf planet Ceres, in July 2012. The spacecraft will be the first to orbit two bodies in our solar system.

FMI: www.nasa.gov/dawn