|
DART, or Demonstration for Autonomous Rendezvous Technology, was a NASA sponsored project with the goal to develop and demonstrate an automated navigation and rendezvous capability in a NASA spacecraft. At the time of the DART mission, only the Russian Space Agency had autonomous space craft navigation. Orbital Sciences Corporation (OSC) was the prime contractor for construction, launch and operation of the DART vehicle with a project cost of $95 million US(2005). The contract was awarded in June 2001 and the spacecraft was launched on April 15, 2005. The mission ended prematurely, very shortly after an anomalous slow-velocity collision with its target spacecraft, having completed less than half of the original mission autonomous rendezvous objectives. == Mission == DART was launched on a Pegasus rocket into a polar circular parking orbit of and has International Designator 2005-014-A. The craft is and weighs . The maneuvering system comprised 16 nitrogen-fueled thrusters with three hydrazine-fueled thrusters and a reaction control system including six nitrogen-fueled thrusters from the Pegasus fourth stage, which forms an integral part of the craft. The target spacecraft was an OSC MUBLCOM (Multiple-Path Beyond-Line-of-Sight Communications) prototype communications relay satellite weighing approximately launched from Vandenberg Air Force Base on 18 May 1999 with International Designator 1999-026-B. After launch, DART successfully achieved orbit and within hours made a rendezvous with the target satellite. The automated systems aboard DART successfully acquired the target and began autonomously approaching it. During proximity operations, multiple malfunctions in navigation, propellant management and collision avoidance programming led to a soft collision with the target and premature departure and retirement of the DART spacecraft. DART had no capability for interactive piloting from the ground or for uploading new programming after launch, thus all on-orbit operations were directed by DART itself based upon pre-programmed criteria. The initial mission was to occur over about 24 hours but its premature failure occurred after only about 11 hours. The launch originally scheduled for October 25, 2004, but this was postponed for launch loads analysis and instead performed April 15, 2005. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「DART (satellite)」の詳細全文を読む スポンサード リンク
|