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DART (spacecraft)

  

DART (spacecraft)

DART, or Demonstration for Autonomous Rendezvous Technology, is a NASA sponsored project. The goal was to develop automated navigation and rendezvous capability and demonstrate it in a space craft. Orbital, the prime contractor, has built, launched and operated the vehicle. The $95 million dollars project was scheduled for launch October 25, 2004, but launch was postponed for launch loads analysis and performed on April 15, 2005.

However, the mission hit a major snag after a successful rendezvous, acquisition of the target spacecraft, and approach to within approximately 100 meters; DART placed itself in the retirement phase before completing all planned proximity operations, ending the mission prematurely.

Currently, only the Russian Space Agency has autonomous space craft navigation.

Mission objectives

Automatic orbital transfer maneuvers


The DART craft has been launched on a Pegasus rocket into a polar, circular parking orbit (472 x 479 miles). The space craft then autonomously navigated with orbit transfer maneuvers to reach the MUBLCOM (Multiple-Path Beyond-Line-of-Sight Communications) satellite. No navigational information was relayed to the vehicle after launch, it navigated autonomously and with GPS.

Proximity operations with AVGS


Once the spacecraft had navigated to the target satellite, it should have performed a series of close proximity maneuvers. The maneuvers would have demonstrated the capabilities of the AVGS (Advanced Video Guidance Sensor). The vehicle would have demonstrated station keeping, docking axis approach, circumnavigation, and a collision avoidance maneuver. DART would have then departed the vicinity and transitioned to its final orbit. The entire sequence was accomplished under autonomous control.

Additional demonstrations

  • Safe operations
  • Validate ground test results of the AVGS and proximity-operations algorithms
  • Provide hardware capabilities for future missions by validating the AVGS in space

    The entire mission should have taken place over a 24 hour period.

    The craft

  • 2 meters long, 1 meter wide, 360 kg (with fuel)
  • 16 Nitrogen fueled thrusters
  • Contract awarded, June 2001
  • Pegasus fourth stage (integral part of the DART craft), three hydrazine-fueled thrusters, and
    the reaction control system includes six nitrogen-fueled
    thrusters

    Mishap investigation board


    NASA is convening a mishap investigation board to determine the reason for the DART spacecraft anomaly. First reports point to the spacecraft running out of fuel before concluding its mission. (Spaceflightnow)

    See also

  • Attitude control
  • Spacecraft

    External links

  • DART at Marshall Space Flight Center
  • Orbital DART site
  • NASA Press release about the DART mishap

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