Galaxy 4

Launch Time
Fri Jun 25, 1993 00:18 UTC

Flight V57.


Ariane 42P
Image Credit: Arianespace
Status: Retired
Liftoff Thrust: 4,334 kN
Payload to GTO: 2,930 kg
Stages: 3
Strap-ons: 2
Rocket Height: 58.72 m

Mission Details

Galaxy 4

Galaxy IV was a model HS-601 satellite built by Hughes Space and Communications Company (HSC). The satellite, which carried a payload of both C band and Ku band transponders, was launched on June 24, 1993, and operated by PanAmSat Corporation. It was in geostationary orbit at 99°W.

Control of Galaxy IV was lost on May 19, 1998, when the satellite's primary control processor failed. The backup control processor had suffered a previously undetected anomaly, and PanAmSat was not able to regain control of the spacecraft. Galaxy IV was declared a loss on May 20, 1998. Failure of the primary control processor was attributed to tin whisker growth, a phenomenon in which tendrils grow from solder, causing an electrical short circuit. Engineers believe that a hole developed in the conformal wax coating over the solder, allowing whiskers to develop. The satellite manufacturer, Hughes, has replaced pure tin plating with nickel to alleviate the problem in newer designs, adding 45 to 90 kg per payload.

Payloads: 1
Total Mass: 2,989.0 kg
Geostationary Transfer Orbit


ELA-2, Guiana Space Centre, French Guiana, France



41st orbital launch attempt


48th mission
2nd mission of 1993
45th successful mission
21st consecutive successful mission

Ariane 4

29th mission
2nd mission of 1993
28th successful mission
21st consecutive successful mission