This artist's concept shows the internal structure of the giant asteroid Vesta, based on data from NASA's Dawn mission. Dawn shows that Vesta has an iron core that is about 68 miles (110 kilometers) in radius, suggesting that Vesta completely melted in its early history, allowing iron to sink to form the core and producing a basaltic crust.

This illustration shows the innermost core in brown, the mantle in green and the crust in gray.

Dawn's mission to Vesta and Ceres is managed by JPL for NASA's Science Mission Directorate in Washington. JPL is a division of the California Institute of Technology in Pasadena. Dawn is a project of the directorate's Discovery Program, managed by NASA's Marshall Space Flight Center in Huntsville, Ala. UCLA is responsible for overall Dawn mission science. Orbital Sciences Corp. in Dulles, Va., designed and built the spacecraft. The German Aerospace Center, the Max Planck Institute for Solar System Research, the Italian Space Agency and the Italian National Astrophysical Institute are international partners on the mission team.

More information about Dawn is online at http://www.nasa.gov/dawn and http://dawn.jpl.nasa.gov.