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Galaxy 4

Also called HGS 4


Designation 22694 / 93039A
Launch date 25 Jun 1993
Country of origin United States
Mission Telecommunications
Geostationary orbit 99°W
Launch vehicle Ariane V57

A fuel cell rupture occured (approx. 22:20 UT on 19 May 1998). The attitude control and backup failed. The satellite was declared a total loss on 20 May. Insurance paid $165 million.

The failure affected millions of pager accross the US. Galaxy 6 was preempted to replace the satellite.

End of life

Out of service 20 May 1998
Cause failure

HGS would have found a customer to use the limited capabilities the satellite still has.

External resources

sat-index articles

Technical data

C-band transponder frequency chart
Ku-band transponder frequency chart

Galaxy 4 also has a special footprint in Ku-band for Hawaii (44 dBW), Alaska (40 dBW) and Puerto Rico (44 dBW), but only for some vertical transponders.

Vertically polarized transponders are theoretically the only transponders that can be made into half transponders. Cross-strapping: C-band transponders 18 and 24 can cross-strap to Ku-band transponders 17 and 23.

Launched using the PVA (Perigee Velocity Augmentation) technic. The transfert orbit is 200/27975 km and then the apogee is upped to 35975 km with the satellite's kick motor and then gradually circularized.

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