Galaxy IV
Mission type | Communications |
---|---|
COSPAR ID | 1993-039A |
SATCAT no. | 22694 |
Spacecraft properties | |
Bus | HS-601 |
Manufacturer | Hughes |
Start of mission | |
Launch date | June 24 1993 |
Rocket | ELA-2 |
Contractor | Arianespace |
Transponders | |
Band | 24 C-band 24 Ku-band |
Galaxy IV was a model
Failure
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 100 to 200 pounds (50 to 90 kg) per payload.[2]
The loss of this satellite was very disruptive to
After the incident, Galaxy IV's assigned orbital slot was briefly occupied by Galaxy 4R, and is now occupied by the Galaxy VI satellite. Galaxy VI's relocation required an emergency order from the FCC, taking one week drift time to change orbit.[5] Galaxy IV remains in space.
References
- ^ "Galaxy 4, 7 / HGS 4". Gunter's Space Page. Retrieved 2021-04-17.
- ^ Felps, Bruce (1999-05-17). "'Whiskers' Caused Satellite Failure: Galaxy IV Outage Blamed On Interstellar Phenomenon". Wireless Week. Archived from the original on March 3, 2009.
- ^ Duke, Alan. "Galaxy 4 satellite not expected to be restored". cnn.com. Archived from the original on 1 October 2000. Retrieved 2 April 2018.
- ^ Trainor, Joseph. "Satellite Failure Causes Communications Chaos". Zeta Talk. Retrieved 2 April 2018.
- ^ PanAmSat Corporation, 13 FCC Rcd. 11,894 (1998).
External links