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Minotaur rocket issue triggers revamped manifest

Posted: January 7, 2010

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A team of industrial and military engineers have designed a fix to the issue grounding the new Minotaur 4 rocket, but an $800 million space tracking satellite waiting for launch could be shuffled behind other payloads in the Air Force manifest.

Credit: Orbital Sciences
The Minotaur 4 has at least eight missions on the books, but the vehicle's maiden flight has faced several delays stemming from problems with satellites and rocket issues.

The latest issue concerns the rocket's third stage, a solid-fueled motor taken from the military's stockpile of Peacekeeper missiles. Furnished by the government, the third stage's thrust vector control steering system exhaust produces "unintended thrust which would cause issues in flight," according to a spokesperson at the Air Force Space and Missile Systems Center.

Engineers from ATK, Orbital Sciences Corp., Northrop Grumman Corp., and the Air Force Space Development and Test Wing are developing a diffuser to attach to the third stage and disperse the exhaust, the Air Force said.

"This will decrease the unintended thrust and mitigate any issues in flight," an Air Force spokesperson said.

The issue affects all Minotaur 4 vehicles, but the Air Force may revamp the rocket's manifest and delay launch of the first Space Based Space Surveillance satellite until the third quarter of this year.

Space News, a space industry media outlet, reported the SBSS launch could be delayed until December.

The first Minotaur 4 mission may now fly from Kodiak Island, Alaska, with a cache of small military, NASA and university satellites managed by the Air Force's Space Test Program. That launch is still officially scheduled for May 28.

In such a schedule, SBSS would launch on the second Minotaur 4 rocket from Vandenberg Air Force Base, Calif.

The Pentagon's TacSat 4 technology demonstration satellite is also awaiting a ride to orbit on the Minotaur 4 rocket.

An SMC spokesperson said the launch manifest scenarios are still being finalized.

In the meantime, the SBSS satellite is being stored at Ball Aerospace and Technologies Corp. in Boulder, Colo., according to Bob Pickard, a Boeing Co. spokesperson

Boeing manages the SBSS contract for the Air Force, and Ball Aerospace built the spacecraft.

Pickard said the satellite is being kept in a launch-ready state while waiting for its rocket to become available. Workers have already completed construction and testing of the spacecraft.

The satellite will join an array of ground-based radars to track thousands of objects in space for the military.