Galaxy IV was a model

HS-601 The Boeing 601 (sometimes referred to as the BSS-601, and previously as the HS-601) is a communications satellite bus designed in 1985 and introduced in 1987 by Hughes Space and Communications Company. The series was extremely popular in the 199 ...

satellite A satellite or artificial satellite is an object intentionally placed into orbit in outer space. Except for passive satellites, most satellites have an electricity generation system for equipment on board, such as solar panels or radioisotope ...

built by

Hughes Space and Communications Company Hughes may refer to: People * Hughes (surname) * Hughes (given name) Places Antarctica * Hughes Range (Antarctica), Ross Dependency * Mount Hughes, Oates Land * Hughes Basin, Oates Land * Hughes Bay, Graham Land * Hughes Bluff, Victoria La ...

(HSC). The satellite, which carried a payload of both C band and K_u band

transponder In telecommunications, a transponder is a device that, upon receiving a signal, emits a different signal in response. The term is a blend word, blend of ''transmitter'' and ''responder''. In air navigation or radio frequency identification, a T ...

s, was launched on June 24, 1993 and operated by

PanAmSat The former PanAmSat Corporation founded in 1984 by Reynold (Rene) Anselmo, was a satellite service provider headquartered in Greenwich, Connecticut, United States. It operated a fleet of communications satellites used by the entertainment ind ...

Corporation. It was in

geostationary orbit A geostationary orbit, also referred to as a geosynchronous equatorial orbit''Geostationary orbit'' and ''Geosynchronous (equatorial) orbit'' are used somewhat interchangeably in sources. (GEO), is a circular geosynchronous orbit in altitud ...

at 99°W.

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 Metal whiskering is a phenomenon which occurs in electrical devices when metals form long whisker-like projections over time. Tin whiskers were noticed and documented in the vacuum tube era of electronics early in the 20th century in equipment th ...

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 per payload. The loss of this satellite was very disruptive to

telecommunications Telecommunication is the transmission of information by various types of technologies over wire, radio, optical, or other electromagnetic systems. It has its origin in the desire of humans for communication over a distance greater than that fe ...

in the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...

. 80% of

pager A pager (also known as a beeper or bleeper) is a wireless telecommunications device that receives and displays alphanumeric or voice messages. One-way pagers can only receive messages, while response pagers and two-way pagers can also acknow ...

service in the U.S. went down; service was not restored until the following day. Many fast-pay gas pumps were not able to verify credit card transactions. Wire news services, like

Reuters Reuters ( ) is a news agency owned by Thomson Reuters Corporation. It employs around 2,500 journalists and 600 photojournalists in about 200 locations worldwide. Reuters is one of the largest news agencies in the world. The agency was estab ...

, were also affected. The TV network

CBS CBS Broadcasting Inc., commonly shortened to CBS, the abbreviation of its former legal name Columbia Broadcasting System, is an American commercial broadcast television and radio network serving as the flagship property of the CBS Entertainmen ...

had to use alternate means of transmitting its programs. All 600

NPR National Public Radio (NPR, stylized in all lowercase) is an American privately and state funded nonprofit media organization headquartered in Washington, D.C., with its NPR West headquarters in Culver City, California. It differs from other ...

-affiliated stations (as well as numerous other broadcasters) lost access to current network shows and newscasts. After the incident, Galaxy IV's assigned orbital slot was briefly occupied by

Galaxy 4R Galaxy 4R was a communications satellite operated by PanAmSat from 2000 to 2006, and by Intelsat from 2006 to 2009. It spent most of its operational life at an orbital location of 99° W, a slot once occupied by the Galaxy IV, which suffered a fai ...

, 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.''PanAmSat Corporation'', 13 FCC Rcd
11,894
(1998). Galaxy IV remains in space.

References

External links

Satellites using the BSS-601 bus Communications satellites in geostationary orbit Derelict satellites orbiting Earth {{communications-satellite-stub Spacecraft launched in 1993