DART falls short of target

NASA's $110 million space experiment on autopilot technology prematurely ended after running out of fuel, officials said Saturday.

The space agency announced the partial mission failure for the Demonstration of Autonomous Rendezvous Technology, or DART, less than 24 hours after its launch from Vandenberg Air Force Base.

DART successfully hitched a ride to space Friday morning aboard an air-launched Pegasus rocket that officials said placed it into proper orbit.

The satellite spent its first few hours in space catching up with its target spacecraft as expected. DART was suppose to conduct its demonstration Friday night as crews at a Vandenberg facility monitored but weren't able to control the pre-programmed spacecraft.

But shortly after acquiring the target, and moving to within 300 feet, DART suddenly placed itself into the retirement phase before finishing all its scheduled maneuvers, NASA said.

Equipped with an advanced video guidance sensor and close proximity sensor, DART was supposed to perform a variety of actions around the target satellite, but never come into contact with it.

The mission was expected to be done 24 hours after the launch and program officials had intended that DART move within 16.5 feet of the spacecraft.

Despite the untimely demise of the mission, some goals were met, prompting Jim Snoddy, DART project manager, to call this a "partial success." Two sensors that make up DART's technological eyes and brains operated for the first time in space, Snoddy said..

"We've done what nobody has ever tried to do before," he said.

DART was designed as a low-cost mission to establish autonomous rendezvous capabilities for the U.S. space program, a critical tool for future exploration missions to Mars and elsewhere.

Engineers designed the satellite to carry enough fuel to perform each operation twice, and had a 30 percent propellant margin.

NASA is convening a mishap investigation board to determine the reason for the DART spacecraft anomaly, officials said.

"The real truth is you have to be perfect in space," Snoddy said. "There was obviously something that we didn't model ... that's what the investigation will go help drive out. They'll tell us what we didn't know, assign the root cause so that all of the future missions can learn from this. This was the first time anybody has ever tried to hand over something totally autonomous in orbit and let it happen. It took a lot of faith to go do that."

* Associate Editor Janene Scully can be reached at 739-2214 or by e-mail at janscully@pulitzer.net.

April 17, 2005