Robotic spacecraft mission cut short

An apparent fuel shortage brought a government space technology demonstration to a premature end in Earth orbit late Friday.

The $110 million robotic spacecraft, known as Demonstration for Autonomous Rendezvous Technology, was designed to test autopiloted rendezvous techniques for U.S. civilian and military space vehicles. It stopped operating less than 24 hours after it was launched from Vandenberg Air Force Base in California.

NASA, which sponsored the mission, said it is convening a mishap investigation board.

Guided by computers and sensors, not an astronaut, DART was to have tracked down an old military communications satellite 500 miles above Earth, closed to within 17 feet, and flown circles around it. Instead, DART shut itself down part of the way through the rendezvous, never approaching closer than 300 feet.

In a Saturday news conference, DART Project Manager Jim Snoddy said the probe operated properly during the rendezvous, despite the fact that a post-launch checkout by ground controllers showed the craft had experienced numerous navigational errors. Snoddy said DART appeared to have run out of maneuvering propellant, although it was launched with extra fuel and there was no evidence of a leak.

Snoddy labeled the mission a partial success. DART accomplished the first rendezvous between U.S. space vehicles without human intervention, but it did not demonstrate autonomous docking maneuvers that both NASA and the Pentagon were eager to see.

NASA will need such docking technology for its moon-Mars exploration initiative, to assemble large exploration vehicles from smaller pieces launched into Earth orbit. The DART mission also was to have laid the groundwork for the development of the Defense Advanced Research Projects Agency's Orbital Express, a satellite refueling and maintenance robot set for a space test in 2006.