NASA Again Postpones Launch of Autonomous DART Spacecraft

NASA once again postponed the launch of the Demonstration of Autonomous Rendezvous Technology (DART) spacecraft Thursday due to the discovery of contamination inside the fairing of its Pegasus launch vehicle.

The launch team does not expect to launch before Nov. 4, 2004.

During the final flight preparations for the DART/Pegasus launch, closeout team members discovered pieces of aluminum foil from the launch vehicle's fairing. As a result, the vehicle will be removed from the carrier aircraft and returned to the vehicle assembly building, where it will be inspected.

The DART mission was postponed twice this week. The first postponement Tuesday was due to a dropout of Global Positioning Satellite (GPS) data of the target vehicle as well as weather fears. The GPS communication glitch was resolved.

DART is expected to launch from the air atop a four-stage Orbital Sciences Pegasus XL rocket in a flight staged from California's Vandenberg Air Force Base. A former passenger jet, Stargazer L-1011, will carry the rocket into launch position 40,000 feet (12,192 meters) above the Pacific Ocean.

NASA researchers believe the autonomous capabilities tested by DART will lay the foundation for future missions beyond Earth orbit, where an autopilot -- instead of real-time remote control -- may be more preferable during dockings. The mission is cooperative effort between NASA researchers and the Orbital Sciences Corporation (OSC), which developed the spacecraft.

While DART's launch marks the first flight of a U.S.-built unmanned rendezvous space vehicle, though the Russian Federal Space Agency's Progress and Soyuz vehicles have docked autonomously with space stations for years. Europe is also planning to launch the cargo ship Jules Verne, the first of its Automated Transfer Vehicles (ATV) to the International Space Station next year.

At the heart of the DART mission is a device called an advanced video guidance sensor (AVGS), which combines advanced optical and electronic ranging systems to approach its satellite target -- the Multiple Paths Beyond Line-of-Site Communications (MUBLCOM) spacecraft launched in 1999.

GPS is used to aid DART's rendezvous, and onboard software will test collision avoidance maneuvers, and direct the spacecraft to fly circles around MUBLCOM. An onboard camera will hopefully catch images of the rendezvous.

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