Dawn mission off to second asteroid

NASA says its Dawn spacecraft is ready for the second leg of its asteroid mission, set to be the first to orbit and study two distant solar system destinations. Dawn will leave the giant asteroid Vesta early Wednesday Eastern time to begin its two-and-a-half-year journey to the dwarf planet Ceres, NASA's Jet Propulsion Laboratory in Pasadena, Calif., reported. Dawn arrived at Vesta in July 2011 on the first leg of its 3 billion-mile asteroid study mission, and is expected to arrive at its second asteroid target in early 2015, JPL said. It will be propelled to Ceres using ion propulsion, a super-efficient system using electricity to ionize xenon to generate thrust. While creating much less thrust than conventional engine, the ion system can deliver continuous thrust for months at a time, engineers said. "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 JPL 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." Dawn captured close-up views of Vesta, revealing unprecedented detail about the giant asteroid. "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 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. We can now say with certainty that Vesta resembles a small planet more closely than a typical asteroid."