Editing Communications satellite (section)

== History ==
=== Origins ===
In October 1945, [[Arthur C. Clarke]] published an article titled "Extraterrestrial Relays" in the British magazine ''[[Wireless World]]''.<ref name="ww-october1945">{{Cite magazine |last=Clarke |first=Arthur C. |author-link=Arthur C. Clarke |date=October 1945 |title=Extra-terrestrial Relays: Can Rocket Stations Give World-wide Radio Coverage? |url=http://clarkeinstitute.org/wp-content/uploads/2010/04/ClarkeWirelessWorldArticle.pdf |url-status=live |magazine=[[Electronics World|Wireless World]] |publisher=Arthur C. Clarke Institute for Space Education |volume=51 |issue=10 |pages=305–308 |archive-url=https://web.archive.org/web/20231119064052/http://clarkeinstitute.org/wp-content/uploads/2010/04/ClarkeWirelessWorldArticle.pdf |archive-date=19 November 2023 |access-date=1 January 2021 }}</ref> The article described the fundamentals behind the deployment of [[satellite|artificial satellite]]s in geostationary orbits to relay radio signals. Because of this, Arthur C. Clarke is often quoted as being the [[invention|inventor]] of the concept of the communications satellite, and the term 'Clarke Belt' is employed as a description of the orbit.<ref name="wapo-19970803">{{Cite news |last=Mills |first=Mike |date=3 August 1997 |title=Orbit Wars |url=https://www.washingtonpost.com/archive/lifestyle/magazine/1997/08/03/orbit-wars/d5840c66-d2c4-4682-bd95-5f97d46b8843/ |url-access=subscription |access-date=18 December 2024 |archive-url=https://web.archive.org/web/20210221123441/https://www.washingtonpost.com/archive/lifestyle/magazine/1997/08/03/orbit-wars/d5840c66-d2c4-4682-bd95-5f97d46b8843/ |archive-date=21 February 2021 |newspaper=[[The Washington Post]] }}{{cbignore}}</ref>

[[File:Sputnik asm.jpg|Replica of Sputnik 1|thumb]]
The first [[Satellite|artificial Earth satellite]] was [[Sputnik 1]], which was put into orbit by the [[Soviet Union]] on 4 October 1957. It was developed by [[Mikhail Tikhonravov]] and [[Sergey Korolev]], building on work by [[Konstantin Tsiolkovsky]].<ref name="airandspace-200711">{{Cite magazine |last=Siddiqi |first=Asif |author-link=Asif Azam Siddiqi |date=November 2007 |title=The Man Behind the Curtain |url=https://www.smithsonianmag.com/air-space-magazine/the-man-behind-the-curtain-22131111/ |url-status=live |magazine=[[Air & Space/Smithsonian]] |issn=0886-2257 |archive-url=https://web.archive.org/web/20231124103036/https://www.smithsonianmag.com/air-space-magazine/the-man-behind-the-curtain-22131111/ |archive-date=24 November 2023 |access-date=1 January 2021 }}</ref> Sputnik 1 was equipped with an on-board [[radio]] [[transmitter]] that worked on two frequencies of 20.005 and 40.002&nbsp;MHz, or 7 and 15 meters wavelength. The satellite was not placed in orbit to send data from one point on Earth to another, but the radio transmitter was meant to study the properties of radio wave distribution throughout the ionosphere.  The launch of Sputnik 1 was a major step in the exploration of space and rocket development, and marks the beginning of the [[Space Age]].<ref name="russianspaceweb-sputnikdesign">{{Cite web |last=Zak |first=Anatoly |year=2017 |title=Design of the first artificial satellite of the Earth |url=https://www.russianspaceweb.com/sputnik_design.html |url-status=live |archive-url=https://web.archive.org/web/20230926121334/https://www.russianspaceweb.com/sputnik_design.html |archive-date=26 September 2023 |access-date=1 January 2021 |website=RussianSpaceWeb.com }}</ref>

=== Early active and passive satellite experiments ===
There are two major classes of communications satellites, ''[[Balloon satellite|passive]]'' and ''active''. Passive satellites only [[Reflector (antenna)|reflect]] the signal coming from the source, toward the direction of the receiver. With passive satellites, the reflected signal is not amplified at the satellite, and only a small amount of the transmitted energy actually reaches the receiver.  Since the satellite is so far above Earth, the radio signal is attenuated due to [[free-space path loss]], so the signal received on Earth is very weak. Active satellites, on the other hand, amplify the received signal before retransmitting it to the receiver on the ground.<ref name="aerospace.org">{{cite web |url=http://www.aerospace.org/2013/12/12/military-satellite-communications-fundamentals/ |title=Military Satellite Communications Fundamentals |website=[[The Aerospace Corporation]] |date=2010-04-01 |access-date=2016-02-10 |archive-url=https://web.archive.org/web/20150905170449/http://www.aerospace.org/2013/12/12/military-satellite-communications-fundamentals/ |archive-date=2015-09-05 |url-status=dead }}</ref> Passive satellites were the first communications satellites, but are little used now.

Work that was begun in the field of electrical intelligence gathering at the [[United States Naval Research Laboratory]] in 1951 led to a project named [[Communication Moon Relay]]. Military planners had long shown considerable interest in secure and reliable communications lines as a tactical necessity, and the ultimate goal of this project was the creation of the longest communications circuit in human history, with the Moon, Earth's natural satellite, acting as a passive relay. After achieving the first transoceanic communication between [[Washington, D.C.]], and Hawaii on 23 January 1956, this system was publicly inaugurated and put into formal production in January 1960.<ref name="nasa-sp-4217">{{Cite book |last=van Keuren |first=David K. |url=https://history.nasa.gov/SP-4217/ch2.htm |title=Beyond The Ionosphere: Fifty Years of Satellite Communication |publisher=[[NASA]] History Office |year=1997 |editor-last=Butrica |editor-first=Andrew J |chapter=Chapter 2: Moon in Their Eyes: Moon Communication Relay at the Naval Research Laboratory, 1951-1962 |bibcode=1997bify.book.....B |id=SP-4217 |archive-url=https://web.archive.org/web/20231029142748/https://history.nasa.gov/SP-4217/ch2.htm |archive-date=29 October 2023 |url-status=live }}</ref>

[[File:Atlas-B with Score payload.jpg|The Atlas-B with SCORE on the launch pad; the rocket (without booster engines) constituted the satellite.|thumb]]
The first satellite purpose-built to actively relay communications was [[SCORE (satellite)|Project SCORE]],  led by [[Advanced Research Projects Agency]] (ARPA) and launched on 18 December 1958, which used a tape recorder to carry a stored voice message, as well as to receive, store, and retransmit messages. It was used to send a Christmas greeting to the world from U.S. President [[Dwight D. Eisenhower]]. The satellite also executed several realtime transmissions before the non-rechargeable batteries failed on 30 December 1958 after eight hours of actual operation.<ref>{{cite book|title=Communications Satellites: Project SCORE|url=http://www.satmagazine.com/story.php?number=768488682|publisher=AIAA|edition=5th|date = March 16, 2007|isbn=978-1884989193|last1=Martin|first1=Donald|last2=Anderson|first2=Paul|last3=Bartamian|first3=Lucy}}</ref><ref>{{cite web|url= https://www.nasa.gov/wp-content/uploads/2024/01/presrep1958.pdf |title= United States Aeronautics and Space Activities - first Annual Report to Congress |date=2 February 1959|work= Published as House Document Number 71, 86th Congress, first Session|publisher=The White House|pages=13–14|access-date=2 January 2021}}</ref>

The direct successor to SCORE was another ARPA-led project called Courier. [[Courier 1B]] was launched on 4 October 1960 to explore whether it would be possible to establish a global military communications network by using "delayed repeater" satellites, which receive and store information until commanded to rebroadcast them. After 17 days, a command system failure ended communications from the satellite.<ref>{{cite web|url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1960-013A|title=Courier 1B|year=2020|publisher=NASA|access-date=3 January 2021}}</ref><ref name=PR1960>{{cite web|url=https://www.nasa.gov/wp-content/uploads/2024/01/presrep1960.pdf |title= United States Aeronautics and Space Activities 1960 |date=18 January 1961|publisher=The White House|pages=12–13, 26|access-date=3 January 2021}}</ref>

[[NASA]]'s satellite applications program launched the first artificial satellite used for passive relay communications in [[Echo 1]] on 12 August 1960. Echo 1 was an aluminized [[balloon satellite]] acting as a passive [[reflection (physics)|reflector]] of [[microwave]] signals. Communication signals were bounced off the satellite from one point on Earth to another. This experiment sought to establish the feasibility of worldwide broadcasts of telephone, radio, and television signals.<ref name=PR1960/><ref>{{cite web|url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1960-009A|title=Echo 1|year=2020|publisher=NASA|access-date=3 January 2021}}</ref>

=== More firsts and further experiments ===

[[Telstar]] was the first active, direct relay communications commercial satellite and marked the first transatlantic transmission of television signals. Belonging to [[AT&T Corporation|AT&T]] as part of a multi-national agreement between AT&T, [[Bell Labs|Bell Telephone Laboratories]], NASA, the British [[General Post Office]], and the [[Orange S.A.|French National PTT]] (Post Office) to develop satellite communications, it was launched by NASA from [[Cape Canaveral]] on 10 July 1962, in the first privately sponsored space launch.<ref>{{cite book|title=Communications Satellites: Telstar|url=http://www.satmagazine.com/story.php?number=511938650|publisher=AIAA|edition=5th|date = March 16, 2007|isbn=978-1884989193|last1=Martin|first1=Donald|last2=Anderson|first2=Paul|last3=Bartamian|first3=Lucy}}</ref><ref name=PR1962>{{cite web|url= https://www.nasa.gov/wp-content/uploads/2024/01/presrep1962.pdf |title= United States Aeronautics and Space Activities 1962 |date=28 January 1963|publisher=The White House|pages=20, 96|access-date=3 January 2021}}</ref>

Another passive relay experiment primarily intended for military communications purposes was [[Project West Ford]], which was led by [[Massachusetts Institute of Technology]]'s [[Lincoln Laboratory]].<ref name=BTI-8>{{cite book|last1=Ward|first1=William W.|last2=Floyd|first2=Franklin W.|url=https://history.nasa.gov/SP-4217/ch8.htm|chapter=Chapter 8: Thirty Years of Space Communications Research and Development at Lincoln Laboratory|title= Beyond The Ionosphere: Fifty Years of Satellite Communication|editor-last=Butrica|editor-first=Andrew J|publisher=NASA History Office|date=1997|bibcode=1997bify.book.....B}}</ref> After an initial failure in 1961, a launch on 9 May 1963 dispersed 350 million copper needle dipoles to create a passive reflecting belt. Even though only about half of the dipoles properly separated from each other,<ref>{{cite web|url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1963-014A-01|title=Project West Ford|publisher=NASA|access-date=4 January 2021}}</ref> the project was able to successfully experiment and communicate using frequencies in the [[Super high frequency|SHF]] [[X band]] spectrum.<ref name=NASAComp5>{{cite web|url= https://ntrs.nasa.gov/api/citations/19760014165/downloads/19760014165.pdf |title= NASA Compendium Of Satellite Communications Programs  |date=December 1975|publisher=NASA|pages=5-1 to 5-16|access-date=4 January 2021}}</ref>

An immediate antecedent of the geostationary satellites was the [[Hughes Aircraft Company]]'s [[Syncom|Syncom 2]], launched on 26 July 1963. Syncom 2 was the first communications satellite in a [[geosynchronous orbit]]. It revolved around the Earth once per day at constant speed, but because it still had north–south motion, special equipment was needed to track it.<ref>{{cite web|url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1963-031A|title=Syncom 2|publisher=NASA|access-date=3 January 2021}}</ref> Its successor, [[Syncom|Syncom 3]], launched on 19 July 1964, was the first geostationary communications satellite. Syncom 3 obtained a geosynchronous orbit, without a north–south motion, making it appear from the ground as a stationary object in the sky.<ref>{{cite web|url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1964-047A|title=Syncom 3|publisher=NASA|access-date=3 January 2021}}</ref>

A direct extension of the passive experiments of Project West Ford was the [[Lincoln Experimental Satellite]] program, also conducted by the Lincoln Laboratory on behalf of the [[United States Department of Defense]].<ref name=BTI-8/> The [[LES-1]] active communications satellite was launched on 11 February 1965 to explore the feasibility of active solid-state X band long-range military communications. A total of nine satellites were launched between 1965 and 1976 as part of this series.<ref>{{cite web|url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1965-008C|title=LES 1|publisher=NASA|access-date=4 January 2021}}</ref><ref name=NASAComp9>{{cite web|url= https://ntrs.nasa.gov/api/citations/19760014165/downloads/19760014165.pdf |title= NASA Compendium Of Satellite Communications Programs  |date=December 1975|publisher=NASA|pages=9-1 to 9-56|access-date=4 January 2021}}</ref>

=== International commercial satellite projects ===
[[File:Stamp of Indonesia - 2016 - Colnect 929988 - Palapa D.jpeg|thumb|A stamp depicting the [[Palapa|Palapa D satellite]]; the Palapa D satellite is a commercial satellite from [[Indonesia]]. ]]
In the United States, 1962 saw the creation of the [[COMSAT|Communications Satellite Corporation]] (COMSAT) private corporation, which was subject to instruction by the US Government on matters of national policy.<ref name=HSA-1>{{cite book|last1=Pelton|first1=Joseph N.|chapter=History of Satellite Communications
|title= Handbook of Satellite Applications |editor=Pelton J. |editor2=Madry S. |editor3=Camacho-Lara S. |publisher=Springer |location=New York |date=2015|bibcode=2017hsa..book.....P}}</ref> Over the next two years, international negotiations led to the Intelsat Agreements, which in turn led to the launch of Intelsat 1, also known as Early Bird, on 6 April 1965, and which was the first commercial communications satellite to be placed in geosynchronous orbit.<ref>{{cite web|url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1965-028A|title=Early Bird|publisher=NASA|access-date=5 January 2021}}</ref><ref name=NASAComp10>{{cite web|url= https://ntrs.nasa.gov/api/citations/19760014165/downloads/19760014165.pdf |title= NASA Compendium Of Satellite Communications Programs  |date=December 1975|publisher=NASA|pages=10-1 to 10-64|access-date=5 January 2021}}</ref> Subsequent Intelsat launches in the 1960s provided multi-destination service and video, audio, and data service to ships at sea (Intelsat 2 in 1966–67), and the completion of a fully global network with Intelsat 3 in 1969–70. By the 1980s, with significant expansions in commercial satellite capacity, Intelsat was on its way to become part of the competitive private telecommunications industry, and had started to get competition from the likes of [[PanAmSat]] in the United States, which, ironically, was then bought by its archrival in 2005.<ref name=HSA-1/>

When Intelsat was launched, the United States was the only launch source outside of the [[Soviet Union]], who did not participate in the Intelsat agreements.<ref name=HSA-1/> The Soviet Union launched its first communications satellite on 23 April 1965 as part of the [[Molniya (satellite)|Molniya]] program.<ref>{{cite web|url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1965-030A|title=Molniya 1-1|publisher=NASA|access-date=5 January 2021}}</ref> This program was also unique at the time for its use of what then became known as the [[Molniya orbit]], which describes a [[highly elliptical orbit]], with two high apogees daily over the northern hemisphere. This orbit provides a long dwell time over Russian territory as well as over Canada at higher latitudes than geostationary orbits over the equator.<ref>{{cite book|last=Altshuler|first=José |url=https://history.nasa.gov/SP-4217/ch18.htm|chapter=Chapter 18: From Shortwave and Scatter to Satellite: Cuba's International Communications|title= Beyond The Ionosphere: Fifty Years of Satellite Communication|editor-last=Butrica|editor-first=Andrew J|publisher=NASA History Office|date=1997|bibcode=1997bify.book.....B }}</ref>

In the 2020s, the popularity of [[low Earth orbit]] [[satellite internet constellation]]s providing relatively low-cost internet services led to reducing demand for new [[geostationary orbit]] communications satellites.<ref name=telegraph-20241204>{{cite news |url=https://www.telegraph.co.uk/business/2024/12/04/airbus-axes-almost-500-jobs-in-britain-after-spacex-steals/ |title=Airbus axes almost 500 jobs in Britain after SpaceX steals a march |last=Jasper |first=Christopher |newspaper=The Daily Telegraph |url-access=subscription |date=4 December 2024 |access-date=5 December 2024}}</ref>