DART was supposed to fly around the satellite and get as close as 15 feet, for another 12 hours before disintegrating in orbit.
"When we started doing precise maneuvers, we started seeing excessive propellant consumption," Snoddy said. "The mission as designed, when it runs out of gas, completes itself."NASA calls the mission a partly success, because it shows that a computer-controlled craft can find a satellite in space without human interference.
There were some navigation errors but no indication of a fuel leak, he said in a conference call. A NASA investigation board will search for the cause of the problem.
More info about the DART mission at ABC News