NASA interplanetary spacecraft sets record

The space agency said a spacecraft's change in velocity refers to its ability to change its path through space by using its own rocket engines.

To reach its present location in the asteroid belt, NASA said Dawn had to fire its three engines -- one at a time -- for a cumulative total of 620 days.

During that time, it used less than 165 kilograms (363 pounds) of xenon propellant.

NASA says its ion-propelled Dawn spacecraft -- en route to explore two of the asteroid belt's most massive objects -- has set a record for velocity change.

Officials said the record previously held by NASA's Deep Space 1 -- the first interplanetary spacecraft to use ion propulsion -- fell Saturday when Dawn's accumulated mission acceleration exceeded 4.3 kilometers per second -- 9,600 mph.

In one year's time, Dawn's ion propulsion system can increase the spacecraft's speed by 8,850 kilometers per hour (5,500 mph), while consuming the equivalent of only 16 gallons of fuel, NASA said.

Dawn's 3-billion-mile mission includes exploration of asteroid Vesta in 2011 and 2012, and the dwarf planet Ceres in 2015.

Dawn, launched in September 2007, is managed by NASA's Jet Propulsion Laboratory in Pasadena, Calif.