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In Earth Orbit, A Rendezvous Managed by Robotic Craft

Associated Press
Sunday, April 17, 2005; Page A09

LOS ANGELES, April 16 -- A NASA robotic spacecraft located a Pentagon satellite in space without help from human controllers, but the mission ended early when the computer-driven craft detected a fuel problem, the mission manager said Saturday.

The experimental DART spacecraft (Demonstration of Autonomous Rendezvous Technology), had moved to within 300 feet of the satellite orbiting 472 miles above the Earth but backed off late Friday, about 11 hours into the mission, manager Jim Snoddy said.

The spacecraft was supposed to have maneuvered around the satellite, getting as close as 15 feet, for 12 more hours. After the problem arose, the 800-pound craft began coasting; it will eventually disintegrate in orbit.

"When we started doing precise maneuvers, we started seeing excessive propellant consumption. . . . It went south pretty quickly," Snoddy said. "The mission as designed, when it runs out of gas, completes itself."

There were some navigation errors but no indication of a fuel leak, he said in a conference call.

Snoddy called the mission a partial success because it demonstrated that a computer-controlled craft could find a satellite in space.

The $110 million mission, classified as high-risk because of its automated controls and relatively low budget, was intended to help lay the groundwork for future projects such as robotic delivery of cargo to space shuttles and automated docking and repair in orbit between spacecraft.

The company that built DART, Orbital Sciences Corp. of Dulles, Va., said it was disappointed in the outcome but pleased with the first part of the mission.


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