Editing Communications satellite (section)

=== Geostationary orbit (GEO) ===
{{Main|Geostationary orbit}}
[[File:Geostat.gif|thumb|[[Geostationary orbit]]]]

To an observer on Earth, a satellite in a gestationary orbit appears motionless, in a fixed position in the sky.  This is because it revolves around the Earth at Earth's own [[angular velocity]] (one revolution per [[sidereal day]], in an [[non-inclined orbit|equatorial orbit]]).

A geostationary orbit is useful for communications because ground antennas can be aimed at the satellite without their having to track the satellite's motion. This is relatively inexpensive.

In applications that require many ground antennas, such as [[DirecTV]] distribution, the savings in ground equipment can more than outweigh the cost and complexity of placing a satellite into orbit.

==== Examples of GEO ====
* The first geostationary satellite was [[Syncom 3]], launched on 19 August 1964, and used for communication across the Pacific starting with television coverage of the [[1964 Summer Olympics]]. Shortly after Syncom 3, [[Intelsat I]], aka ''Early Bird'', was launched on 6 April 1965 and placed in orbit at 28° west longitude. It was the first geostationary satellite for telecommunications over the Atlantic Ocean.
* On 9 November 1972, Canada's first geostationary satellite serving the continent, [[Anik A1]], was launched by [[Telesat Canada]], with the United States following suit with the launch of [[Westar 1]] by [[Western Union]] on 13 April 1974.
* On 30 May 1974, the first geostationary communications satellite in the world to be [[three-axis stabilized]] was launched: the experimental satellite [[ATS-6]] built for [[NASA]].
* After the launches of the Telstar through Westar 1 satellites, RCA Americom (later GE Americom, now [[SES (company)|SES]]) launched [[Satcom 1]] in 1975.  It was Satcom 1 that was instrumental in helping early [[cable TV]] channels such as WTBS (now [[TBS (U.S. TV channel)|TBS]]), [[HBO]], [[Christian Broadcasting Network|CBN]] (now [[Freeform (TV channel)|Freeform]]) and [[The Weather Channel (United States)|The Weather Channel]] become successful, because these channels distributed their programming to all of the local cable TV [[Cable television headend|headends]] using the satellite.  Additionally, it was the first satellite used by broadcast television networks in the United States, like [[American Broadcasting Company|ABC]], [[NBC]], and [[CBS]], to distribute programming to their local affiliate stations.  Satcom 1 was widely used because it had twice the communications capacity of the competing Westar 1 in America (24 [[Transponder (Satellite communications)|transponders]] as opposed to the 12 of Westar 1), resulting in lower transponder-usage costs. Satellites in later decades tended to have even higher transponder numbers.
By 2000, Hughes Space and Communications (now [[Boeing Satellite Development Center]]) had built nearly 40 percent of the more than one hundred satellites in service worldwide. Other major satellite manufacturers include [[Space Systems/Loral]], [[Orbital Sciences Corporation]] with the [[Star Bus]] series, [[Indian Space Research Organisation]], [[Lockheed Martin Space Systems|Lockheed Martin]] (owns the former RCA Astro Electronics/GE Astro Space business), [[Northrop Grumman]], Alcatel Space, now [[Thales Alenia Space]], with the [[Spacebus]] series, and [[Astrium]].