August 31, 2012
Dawn Spacecraft To Leave Vesta, Sets Sights On Dwarf Planet
Watch the Video: Dawn Spacecraft's Farewell Portrait of Giant Asteroid Vesta
Lee Rannals for redOrbit.com - Your Universe Online
The spacecraft arrived at Vesta in July 2011 after launching in 2007 on a 3-billion-mile journey towards the asteroid belt. NASA said Dawn will be reaching Ceres in early 2014.
Dawn will spiral away gently from Vesta, using a special, hyper-efficient system called ion propulsion. The spacecraft's ion propulsion system uses electricity to ionize xenon to generate thrust.
The 12-inch-wide ion thrusters provide less power than conventional engines, but can maintain thrust for months at a time.
"Thrust is engaged, and we are now climbing away from Vesta atop a blue-green pillar of xenon ions," Marc Rayman, Dawn's chief engineer and mission director, at NASA's Jet Propulsion Laboratory, said. "We are feeling somewhat wistful about concluding a fantastically productive and exciting exploration of Vesta, but now have our sights set on dwarf planet Ceres."
The spacecraft's orbit helped provide NASA with close-up views of Vesta, giving scientists a better understanding of the asteroid.
Dawn helped reveal that Vesta completely melted in the past, and formed a layered body with an iron core. The spacecraft also revealed the abusive past the asteroid has taken from other collisions.
"We went to Vesta to fill in the blanks of our knowledge about the early history of our solar system," Christopher Russell, Dawn's principal investigator, based at the University of California Los Angeles (UCLA), said. "Dawn has filled in those pages, and more, revealing to us how special Vesta is as a survivor from the earliest days of the solar system."
Without Dawn, scientists would still be left in the dark when knowing about the troughs that sculpted Vesta.
"We can now say with certainty that Vesta resembles a small planet more closely than a typical asteroid," Russell said.