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Steering system work delays Minotaur rocket launch BY JUSTIN RAY SPACEFLIGHT NOW Posted: March 15, 2005 Engineers have elected to replace a vital control unit inside the steering system of an Orbital Sciences Minotaur rocket, delaying Friday's launch of the vehicle and its Air Force spacecraft cargo by several weeks.
But concerns over reliability of some capacitors within a box called the Thrust Vector Controller (TVC) led to the postponement, the Air Force said Tuesday. These boxes control the steering of the Minotaur's engine nozzles during ascent. "The capacitors in the TVC come from two different vendors. It was determined in testing and physical examination after the tests that one vendor's capacitors are significantly more robust than another's," according to officials at the Air Force Space and Missile Systems Center. "Concerns over capacitors have existed for some months, and all TVCs received additional box-level testing as a result. The intent of the additional testing was to screen out questionable capacitors or workmanship. "Testing over the last several days of individual capacitors revealed that box-level testing might not catch all potential defects, and that one vendor's capacitor was more robust. It was therefore decided to take a conservative approach and change to the more robust capacitor." The controllers used on Minotaur rockets are the same carried aboard Orbital Sciences' air-launched Pegasus vehicles. A circuit card or possibly an entire TVC featuring the better capacitors will be removed from the Pegasus earmarked to launch the Air Force's C/NOFS satellite later this year for installation on this Minotaur. Plans are still being developed for the replacement work. But the Air Force says initial estimates suggest the Minotaur could be ready for the $80 million launch in late April. This will be the third Minotaur flight, following two successful missions in 2000. The rocket incorporates decommissioned first and second stages from a Minuteman 2 ICBM missile and solid-fuel motors from Pegasus for third and fourth stages. The vehicle is designed to provide the U.S. government with reliable access to space for small satellites. The 319-pound XSS-11 spacecraft was built by Lockheed Martin at its facilities near Denver for the Air Force Research Laboratory. |
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The fifth Lockheed Martin Atlas 5 rocket blasts off to deploy the Inmarsat 4-F1 mobile communications spacecraft into orbit. (2min 35sec file)
An extended length clip follows the Atlas 5 launch from T-minus 1 minute through ignition of the Centaur upper stage and jettison of the nose cone. (6min 43sec file)
An onboard video camera mounted to the Atlas 5 rocket's first stage captures this view of the spent solid-fuel boosters separating.
This view of the Atlas 5 launch was recorded from the Kennedy Space Center Press Site. (1min 27sec file)
The Boeing Delta 4 rocket to launch the next GOES geostationary U.S. weather satellite is rolled to Cape Canaveral's pad 37B for its spring blastoff. (2min 08sec file)
The pad erector arm lifts the Delta 4 rocket upright, standing the vehicle onto the launch table. (4min 00sec file)
The STS-114 return-to-flight space shuttle astronauts inspect Discovery's thermal tiles and wing leading edge panels during the Crew Equipment Interface Test activities at Kennedy Space Center. (2min 26sec file)
The astronauts don coveralls and go into space shuttle Discovery's payload bay for further examinations during the Crew Equipment Interface Test in the orbiter hangar. (1min 25sec file)
A long mission simulation is underway to rehearse the launch of space shuttle Discovery, the uncovering of impact damage and the decision-making process of the flight controllers and management team. (14min 31sec file)