Galaxy 8i Primary Propulsion System Fails

Galaxy VIII-i satellite is experiencing problems with its primary propulsion system, an anomaly that could shorten its operational life. The satellite is owned and operated by PanAmSat for Galaxy Latin America. Galaxy Latin America, which delivers DirecTV service throughout Central and South America was the exclusive customer for all of the satellite’s 32 Ku-band transponders.

The satellite has a failing xenon ion propulsion system (XIPS), an electric propulsion system used to maintain the spacecraft's proper orbit and attitude. The satellite has lost at least three of its four XIPS thrusters. Without the XIPS, the spacecraft is expected to reach its end-of-life in late 2002. The satellite was originally expected to operate through 2012. The satellite has switched to a backup chemical propulsion system, and is operating normally. PanAmSat and Hughes Space and Communications are continuing to investigate the causes of the problem and possible solutions.

PanAmSat will build a replacement for Galaxy Latin America. The new bird, Galaxy IIIC, will go into the same orbital location as Galaxy VIII-i. Galaxy IIIC is a Hughes-built HS 702 spacecraft that was planned to provide C-band and Ku-band coverage of the Americas upon its launch during the second quarter of 2001. When Galaxy IIIC reaches orbit Galaxy Latin America will be able to transition to Galaxy IIIC as its primary transmission platform, without requiring the re-pointing of any DirecTV dishes in Latin America. PanAmSat will also build Galaxy VIII-iR to assure against a Galaxy IIIC launch failure and provide for a more robust in-orbit back-up configuration.

Galaxy VIII-i is an HS 601 HP satellite built by Hughes Space and Communications which was launched in December 1997. In 1998 the satellite suffered battery cell failures occurred which has made it necessary to shut off a substantial number of transponders for brief periods during the eclipses.

PAS-5,  was the first Hughes satellite equipped with XIPS, but the system was only used for North-South stationkeeping. Galaxy VIII-i was the first Hughes satellite to fully rely on XIPS for stationkeeping. PanAmSat operates five other HS 601 HP spacecraft that use XIPS (Galaxy XI, Galaxy XR, Galaxy IVR, PAS-5, PAS-6B) as well as one HS 702 spacecraft (PAS-9). By mid-2001, PanAmSat has planned to launch one additional HS 601 HP spacecraft, and two HS 702 spacecraft, all of which use a XIPS propulsion system. The HS 702 does use a different XIPS system than the HS 601. First reports about Galaxy VIII-i problems with XIPS thrusters surfaced a few months ago. 
  

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