DIRECTV TAKES TROUBLED BOEING SATELLITE OUT OF SERVICE
DirecTV 3 satellite has been taken out of service because of fear it could collide with other orbiting spacecraft, company said Tues. DirecTV 3, which was launched in 1995, lost its primary spacecraft control processor in May and was switched automatically to backup processor, but company has become increasingly concerned about ability of ground controllers to maneuver satellite if backup processor failed.
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Satellite was moved out of orbit because of concern that it could collide with another satellite if backup processor failed, DirecTV said. DirecTV 3 is among fleet of Boeing HP- 601 satellites that have experienced problems with control processors. It’s older model satellite that’s using processor that hasn’t been updated.
Moving satellite was “precautionary measure,” spokesman said. DirecTV placed satellite into “storage orbit” to control it because “spacecraft control processors are unpredictable,” spokesman said. “We can bring it back if we need it. It still has the capability to work.” Spokesman said Spare Space Control Processor was working properly: “It will just remain at storage orbit” until company decides what to do.
Service to customers hasn’t been hurt by problems or removal of transponders, DirecTV said. Company began transferring service off DirecTV 3 after finding primary processors had stopped working, spokesman said. Official of PanAmSat, which also operates 601s, said Boeing 601 satellites that had faulty processors couldn’t be considered reliable because if one of processors failed, likelihood that 2nd or backup would fail was “reasonably high.” DirecTV 3 is in nongeostationary orbit 308 km above primary position at 101 degrees W where it was colocated with 3 other DirecTV satellites. FCC authorized DirecTV to move DirecTV 3 on Sept. 23.
DirecTV 3 is latest in Boeing’s 601 line to suffer problems. Boeing found defects in coating intended to prevent short circuits in processors, but problems weren’t corrected until later 601s. Boeing said it had made provisions in quality control that now prevented launch of satellites with defective components.
Problems with Boeing 601s started in 1998 when PanAmSat lost Galaxy 4 satellite because of faulty processors. PanAmSat Galaxy 7 was taken out of service in 2000 because of recurring problems with processors. PanAmSat PAS-4 is operating, but customers are receiving discounts because of fears it could suffer anomaly at any time. PanAmSat Galaxy 3R also experienced problems with primary spacecraft control processor, but satellite currently is operating efficiently using backup system (CD April 26/2001 p8). SatMex lost Solidaridad 1 satellite when it ended service in Aug. 2000 as both of its processors stopped operating. DirecTV spokesman said solar cell degradation also caused power failures in Boeing 701s (CD Sept 28 p3). Problems of 601s and 701s are unrelated, satellite official said.