NASA’s Dawn Mission Approaches “Minor Planet” Vesta

The Dawn mission, managed by the Jet Propulsion Laboratory, currently has its Dawn spacecraft on it way to Vesta. The spacecraft, powered by ion engine technology, should reach Vesta to begin it observations by mid-summer.

“Dawn’s ion thrusters are gently carrying us toward Vesta, and the spacecraft is getting ready for its big year of exploration,” said Marc Rayman, Dawn’s chief engineer at NASA’s Jet Propulsion Laboratory, Pasadena, Calif. “We have designed our mission to get the most out of this opportunity to reveal the exciting secrets of this uncharted, exotic world.”

Vesta is located in the massive asteroid belt which orbits the sun between Mars and Jupiter, but it is not exactly an asteroid. A variety of factors including its size, shape and composition currently have Vesta classified as a “minor planet.” As the number of spacecraft exploring our solar system has increased in recent years, scientists have had to rethink their categorization of objects. Most famously, Pluto lost its status as our ninth planet a few years ago.

“I don’t think Vesta should be called an asteroid,” said Tom McCord, a Dawn co-investigator based at the Bear Fight Institute, Winthrop, Wash. “Not only is Vesta so much larger, but it’s an evolved object, unlike most things we call asteroids.”

Once Dawn gets close enough to study Vesta in July, scientists should be able to better classify the object. It is hoped that by studying a large crater on the south pole of Vesta, they should be able to get a good look at the layers of the crust. Unlike its nearby asteroids, Vesta still had enough radiation within itself when it formed to continue to melt internal rock resulting in lighter layers floating out toward the surface, a process known as differentiation.

Source: NASA