WASHINGTON? A contingency plan to raise the altitude of the U.S. Air Force?sfirstAdvanced Extremely High Frequency satellite after one of its thrustersystemsfailed on orbit is moving along on schedule, a service official saidOct. 5.
Thesecure communications satellite AEHF-1, built by Lockheed Martin SpaceSystems of Sunnyvale,Calif., was successfully launched Aug. 14 into a highly ellipticalorbit ranging from230 kilometers above Earth at perigee to 50,000 kilometers above Earthatapogee. But shortly after launch, an engine malfunction left thesatelliteunable to reach its intended orbit as planned.
Thesatellite was designed to use its hydrazine-fueled liquid apogee enginetoraise its perigee to 19,000 kilometers over 30 days, and then use itsxenon-ionelectric thrusters to circularize its orbit at 36,000 kilometers over90 days.
Operatorsfirst attempted to fire the satellite?s liquid apogee engine Aug. 15,but itfailed. The Air Force announced Aug. 30 it had begun to implement abackup planto raise the satellite?s perigee to 19,000 kilometers using smalleronboard thrustersfueled by the same hydrazine tank as the liquid apogee engine.
Theplan is expected to take an additional six to seven months to completebut willnot reduce the satellite?s operational lifespan.
Fiveweeks into the contingency plan, the AEHF-1?s perigee has been raisedto about4,700 kilometers and the satellite remains on schedule to reach itsfinalgeostationary orbit between June 2011 and August 2011, Air Force SpaceandMissile Systems Center spokesman Joe Davidson said in an Oct. 5e-mailedresponse to questions.
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