View source for Skynet (satellite)

{{Short description|Communications satellite}}
{{EngvarB|date=June 2019}}
{{Use British English|date=April 2021}}
{{Use dmy dates|date=June 2019}}

[[File:Skynet-5 satellite.jpg|thumb|upright=1.0|right|An artist's impression of a Skynet 5 satellite]]

'''Skynet''' is a family of [[armed force|military]] [[communications satellite]]s, now operated by [[Babcock International]] on behalf of the United Kingdom's [[Ministry of Defence (United Kingdom)|Ministry of Defence]] (MoD).<ref>{{cite web | url=https://www.gov.uk/government/news/400-million-contract-to-operate-military-satellite-communications-system-supports-400-uk-jobs | title=£400 million contract to operate military satellite communications system supports 400 UK jobs }}</ref><ref>{{cite web | url=https://www.babcockinternational.com/news/babcock-awarded-contract-to-operate-skynet-the-mod-satellite-communications-system/ | title=Babcock awarded contract to operate Skynet – the MOD satellite communications system | date=15 February 2023 }}</ref><ref>{{cite web | url=https://www.defensenews.com/global/europe/2023/02/15/babcock-wins-480-million-bid-to-run-britains-skynet-satcom-program/ | title=Babcock wins $480 million bid to run Britain's Skynet SATCOM program | date=15 February 2023 }}</ref> They provide strategic and tactical communication services to the branches of the [[British Armed Forces]], the [[British intelligence agencies]], some UK government departments and agencies, and to allied governments. Since 2015 when Skynet coverage was extended eastward, and in conjunction with an [[Anik (satellite)#Anik G1|Anik G1]] satellite module over America, Skynet offers near global coverage.<ref name=ukspace-20160914/>

The Skynet contract allow Airbus Defence and Space to sell surplus bandwidth, through the Skynet partner programme, to [[NATO]] and allied governments, including the [[Five Eyes]] intelligence alliance members (Australia, Canada, New Zealand, the United Kingdom and the United States).<ref name=ukspace-20160914/> As of 2020, seven Skynet satellites are operating, plus Anik G1.

The Skynet 1 to 4 series were developed and operated by the [[Signals Research and Development Establishment]], [[Royal Signals and Radar Establishment]] and [[Royal Air Force]] until 2003.<ref name=rafmuseum-20170630/> It was subsequently operated with Skynet 5 by [[Paradigm Secure Communications]] until October 2012, when the organisation was rebranded to Astrium Services then through merger in 2015 became Airbus Defence and Space.<ref>{{cite web|url=https://www.paradigmsecure.com/|title=Government Communications |publisher=Paradigm Services|access-date=28 May 2015|url-status=dead|archive-url=https://web.archive.org/web/20141028125235/https://www.paradigmsecure.com/|archive-date=28 October 2014}}</ref>

The MoD is currently specifying a new architecture for Skynet to replace the Skynet 5 system, whose funding programme ends in August 2022. The vision for Skynet 6 is a flexible system architecture that combines UK government, allied and commercial satellites, including the current Skynet 5 satellites.<ref name=spacenews-20181106/><ref name=bbc-20200720/> Skynet is the large part of the MoD [[Future Beyond Line of Sight]] satellite communications programme (FBLOS), which extends to 2041, with expected transition costs of about £6 billion.
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== History ==
[[File:Delta-M with Skynet-1A.jpg|thumb|upright=1.0|right|Launch of the first Skynet satellite, Skynet 1A, by [[Delta (rocket family)|Delta rocket]] in 1969 from [[Cape Canaveral]]]]

In the 1960s, only two countries utilised communications satellites, the United States and the [[Soviet Union]]. The United Kingdom created Skynet as its own military communications satellite system, because of inadequate [[undersea communications cable]] availability and to increase flexibility, reliability, data capacity and security.<ref name="Aldrich-2011,347-348" >{{cite book |pages=347–348 |url=https://books.google.com/books?id=l9i5bt1-7HYC |last=Aldrich|first=Richard J. |year=2011 |title=GCHQ |location=London |publisher=Harper Press |isbn=978-0-007312-665}}</ref><ref name=rsre-198704/> The [[Signals Research and Development Establishment]] led the development of Skynet 1 and 2, and its successor [[Royal Signals and Radar Establishment]] carried out research for the development of the subsequent satellites and ground terminals.<ref name=mraths-201807>{{cite web|url=https://mraths.org.uk/?page_id=2868|title=Defford Satellite Communications|last=Harris|first=Dick |publisher=Malvern Radar and Technology History Society|date=July 2018|access-date=19 January 2021}}</ref><ref name=rsre-198901>{{cite report|url=https://apps.dtic.mil/dtic/tr/fulltext/u2/a209863.pdf |archive-url=https://web.archive.org/web/20210815165821/https://apps.dtic.mil/dtic/tr/fulltext/u2/a209863.pdf |url-status=live |archive-date=15 August 2021 |title=Tactical UK Military Satellite Ground Terminals - A Research and Development Review|author=P. J. Skilton|publisher=Royal Signals and Radar Establishment|id=RSRE Memorandum 4262|date=January 1989|access-date=19 January 2021}}</ref>

The MoD space communications research programme began in 1962, initially considering Moon and [[space debris]] bounce techniques, before considering a UK satellite. In 1964, it was decided Skynet should be in [[geostationary orbit]] over the [[Indian Ocean]], significantly to support [[East of Suez]] deployments, and have a transponder with two channels permitting communications between two types of ground station. This would be an advance over the ongoing U.S. [[Defense Satellite Communications System|Interim Defense Communication Satellite Program]] (IDCSP).<ref name=burr-201202/> In 1965, the U.S. invited the MoD to participate in their IDCSP programme, and to participate [[Marconi Company|Marconi]] were contracted to build three 40 foot diameter air transportable ground stations for the launch of the first IDCSP satellites in 1966. As Britain had insufficient industry expertise to build satellites, a contact was placed with U.S. [[Philco Ford]] to build Skynet 1, but with the assistance of Marconi to improve UK expertise for Skynet 2.<ref name=mraths-skynet-201807>{{cite web|url=https://mraths.org.uk/?page_id=2836|title=Skynet|last=Harris|first=Dick|publisher=Malvern Radar and Technology History Society|date=July 2018|access-date=21 January 2021}}</ref>

Nine ground stations were initially planned, which could also communicate with sub-geostationary U.S. IDCSP satellites:<ref name=burr-201202>{{cite book|url=http://woottonbridgeiow.org.uk/decca-legacy/ |title=The Decca Legacy - a View From Inside the Radar Company Decca - BAe Systems 1949-2009|last=Burr|first=Ron|publisher=Wootton Bridge Historical|chapter=Chapter 14.2 - Satellite Communications|chapter-url=http://woottonbridgeiow.org.uk/decca-legacy/chapter14.php#14.2|date=February 2012|access-date=21 January 2021}}</ref>
* three principal stations at [[RAF Oakhanger]], [[Akrotiri and Dhekelia|Cyprus]] and [[Singapore Naval Base|Singapore]] with 40 foot [[Satellite dish|dishes]] and 20 [[Watt|kW]] transmitters
* two stations at [[HMS Jufair]] and [[RAF Gan]] (Indian Ocean) with air transportable 20 foot dishes and 5kW transmitters called SKYNET V
* two additional air-transportable stations
* two [[Royal Navy]] ship stations with 6 foot dishes and 5kW transmitters, initially installed on {{HMS|Fearless|L10}} and {{HMS|Intrepid|L11}} but movable to {{HMS|Hermes|R12}} and {{HMS|Ark Royal|R09}} as required

'''Skynet 1A''' was the first military satellite in [[geostationary orbit]], in 1969.<ref name=rsre-198901/> The [[Royal Air Force]] displayed a model of the Skynet satellite on the children's television show ''[[Blue Peter]]'' in 1969, the show also described the new British satellite control centre at [[RAF Oakhanger]].<ref name="Aldrich-2011,347-348"/>

The Skynet satellites provided secure and encrypted facilities, though expensively, for the British armed forces and intelligence agencies. It enables an important sovereign command and control service.<ref name=kcl-202011>{{cite report|pages=3, 11–13, 15–16|url=https://www.kcl.ac.uk/security-studies/assets/kcl-fasi-british-spacepower-and-the-integrated-review-web4.pdf|title=The Integrated Review and UK Spacepower: The Search for Strategy|author=Bleddyn E. Bowen|work=Freeman Air and Space Institute|publisher=King's College London|date=November 2020|access-date=11 March 2021}}</ref> The largest user of the Skynet satellites during the [[Cold War]] was the [[Government Communications Headquarters]] (GCHQ),<ref name=bowen-2019/> who were responsible for over 80% of traffic at some locations such as [[Akrotiri and Dhekelia|Cyprus]].<ref name="Aldrich-2011,347-348"/> Despite the enormous communications capability of Skynet, GCHQ still found the capacity provided by Skynet to be inadequate.<ref name="Aldrich-2011,347-348"/> In 1972, GCHQ was still the satellite's largest funder, and argued for the purchase of an American built Type-777 ([[DSCS II]]) satellite instead.<ref name="Aldrich-2011,347-348"/> GCHQ would later plan their own secret [[signals intelligence]] satellite, [[Zircon (satellite)|Zircon]], which was subsequently cancelled. The circumstances around the reporting of Zircon's existence would become known as the [[Zircon affair]].<ref name=BBC-history>{{cite web |last=Wilby|first=David |title=The Zircon Affair 1986-1987 |url=https://www.bbc.co.uk/historyofthebbc/resources/bbcandgov/pdf/zircon.pdf |publisher=BBC |access-date=1 June 2013 |url-status=dead |archive-url=https://web.archive.org/web/20120905221545/http://www.bbc.co.uk/historyofthebbc/resources/bbcandgov/pdf/zircon.pdf |archive-date=5 September 2012}}</ref>

Skynet has throughout all its models had a good degree of interoperability with U.S. and NATO military communications satellites and ground stations.<ref name=bowen-2019>{{cite journal |url=https://www.raf.mod.uk/what-we-do/centre-for-air-and-space-power-studies/documents1/air-and-space-power-review-vol-22-no-2/|title=A Familiar Frontier: British Defence Strategy and Spacepower|last=Bowen |first=Bleddyn|journal=Air and Space Power Review|volume=22|issue=2|publisher=Royal Air Force|pages=6–14|date=Summer 2019|access-date=28 January 2021}}</ref>

In 2010, the [[Civil Contingencies Secretariat]] of the [[Cabinet Office]] launched the [[High Integrity Telecommunications System]], a satellite-based emergency communications service based on Skynet, for use by [[UK police]] and other emergency services, primarily for use at Strategic Command Centres and at major events and emergencies. It replaced the earlier Emergency Communications Network.<ref name=hits-201009>{{cite web |url=https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/61209/hits_informationpack_v1.1_0.pdf|title=HITS Information Pack|publisher=Cabinet Office, Civil Contingencies Secretariat|date=September 2010|access-date=28 January 2021}}</ref><ref name=hits-2011>{{cite web |url=https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/61211/HITS_Brochure_Jan2011.pdf|title=High Integrity Telecommunications System|publisher=Cabinet Office |year=2011|access-date=28 January 2021}}</ref>

In 2021 [[UK Space Command]] was created, which when fully operational will take over responsibility for Skynet from [[Strategic Command (United Kingdom)|Strategic Command]] (previously known as Joint Forces Command), likely in 2023.<ref name=mod-20210401>{{cite web |url=https://www.gov.uk/guidance/uk-space-command |title=UK Space Command |website=Ministry of Defence |date=1 April 2021 |access-date=23 June 2021}}</ref><ref name=janes-20220511>{{cite news |url=https://www.janes.com/defence-news/news-detail/defence-space-2022-uk-space-command-details-future-plans |title=Defence Space 2022: UK Space Command details future plans |last=Savage |first=Olivia |publisher=IHS |work=Jane's |date=11 May 2022 |access-date=14 July 2022}}</ref>

== Models ==
=== Skynet 1 ===
There were two Skynet 1 satellites (1A and 1B); '''Skynet 1A''' was launched on a [[Delta (rocket family)#Delta M|Delta M]] on 22 November 1969, but the satellite failed after about 18 months when all of its [[Traveling-wave tube|Traveling Wave Tube Amplifiers]] (TWTAs) had failed, probably due to soldered high voltage joints failing under thermal cycling.<ref name=mraths-skynet-201807/> '''Skynet 1B''' was launched on a [[Delta (rocket family)#Delta M|Delta M]] on 19 August 1970. Skynet 1B was placed in a [[geostationary transfer orbit]] (GTO) and was abandoned in transfer orbit (270 x 36058&nbsp;km) due to a failure of the [[Thiokol]] [[Star 17|Star 17A]] [[apogee kick motor]].<ref>{{cite web|url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1970-062A|title=Display: Skynet 1B 1970-062A|publisher=NASA|date=13 April 2021 |access-date=18 April 2021}} {{PD-notice}}</ref>

Skynet 1 series satellites had an orbit mass of {{cvt|122|kg}}, were [[Spin stabilization|spin-stabilised]] with a single despun antenna with 3 [[watt]]s of output on two channels (2 [[Hertz|MHz]] and 20&nbsp;MHz).<ref name=rsre-198901/> The [[NATO|North Atlantic Treaty Organization]], '''NATO 2A''' and '''NATO 2B''' satellites, launched 1970 and 1971, were identical except for an antenna shaped to only cover NATO countries.<ref name=gunter-nato2>{{cite web|url=https://space.skyrocket.de/doc_sdat/nato-2.htm|title=NATO 2A, 2B|publisher=Gunter's Space Page|date=11 December 2017|access-date=18 April 2021}}</ref>

=== Skynet 2 ===
[[File:Skynet 2B satellite being unpacked at Cape Canaveral, Florida, USA - 19741003.jpg|thumb|upright=1.0|right|Skynet 2B being unpacked at Cape Canaveral for launch processing. It was successfully launched 23 November 1974.]]

Following the operational failure of the Skynet 1A satellite, the timetable for the launch of the Skynet 2 communications satellite was delayed. '''Skynet 2A''' was launched on the [[Delta (rocket family)|Delta 2313]] by [[NASA]] for the United Kingdom on 19 January 1974.<ref>{{cite web|url=http://kevinforsyth.net/delta/log.php|title=History of the Delta Launch Vehicle: Flight Log|author=Kevin S. Forsyth}}</ref>  A short circuit in an electronics package circuit board (on second stage) left the upper stages and satellite in an unstable low orbit (96 x 3406&nbsp;km x 37.6°) that rapidly decayed. An investigation revealed that a substandard coating had been used on the circuit board.<ref>{{cite web|url=http://www.spacelaunchreport.com/thorh10.html|archive-url=https://archive.today/20121208210354/http://www.spacelaunchreport.com/thorh10.html|url-status=usurped|archive-date=8 December 2012|title=Delta 2000 series|publisher=Space Launch Report|date=9 April 2010|last=Kyle |first=Ed}}</ref>

Despite being in an unstable orbit, the ground stations successfully located and tracked Skynet 2A and were able to use telemetry readings from the [[Solar panels on spacecraft|solar panels]] to determine its alignment. Based on this analysis, it was decided to use the alignment thrusters to deorbit the unit, and it was destroyed when it re-entered the Earth's atmosphere on 24 January 1974.<ref>{{cite web |url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1974-002A|title=Display: Skynet 2A 1974-002A|publisher=NASA|date=13 April 2021|access-date=18 April 2021}} {{PD-notice}}</ref>

'''Skynet 2B''' was successfully launched on the [[Delta (rocket family)|Delta 2313]] by NASA for the United Kingdom on 23 November 1974.<ref>{{cite web |url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1974-094A|title=Display: Skynet 2B 1974-094A|publisher=NASA|date=13 April 2021|access-date=18 April 2021}} {{PD-notice}}</ref> It was positioned in [[geostationary orbit]] above [[Kenya]] to give coverage of Europe, [[Africa]] and a substantial part of [[Asia]] as far east at the [[Philippines]]. It could support about ten simultaneous users. Major ground stations used a 40-foot diameter [[Satellite dish|dish]], while in the field or at sea a 2 m diameter dish was used.<ref name=commsmuseum-2007>{{cite web |url=https://www.commsmuseum.co.uk/dykes/satcoms/satcoms.htm|title=Satellite Communications|last=Dykes|first=Godfrey|publisher=Communications Branch Museum/Library|year=2007|access-date=14 January 2021}}</ref>

Skynet 2 satellites had an orbit mass of {{cvt|250|kg}}, with a single antenna with 16 watts of output.<ref name=rsre-198901/>

[[File:Skynet 2 satellite being packed for shipment.jpg|thumb|upright=1.0|right|A Skynet 2 satellite being packed for shipment]]

The Skynet 2 series satellites were assembled and tested at the [[Marconi Company|Marconi Space and Defence Systems]] establishment in [[Portsmouth]], England, and were the first non-amateur <ref>The first communications satellite built outside the U.S. and former USSR appears to have been [[Australis-OSCAR 5]], built at the [[University of Melbourne]] in [[Victoria (Australia)|Victoria]], Australia and launched from Vandenberg Air Force Base on 23 January 1970.</ref> communication satellites built outside the United States and [[Soviet Union|USSR]].<ref>{{cite web|title=Minisatellites 1970-1980 |url=http://centaur.sstl.co.uk/SSHP/mini/mini70s.html|publisher=Surrey Satellite Technology Limited|access-date=2007-10-08|url-status=dead|archive-url=https://web.archive.org/web/20070927161133/http://centaur.sstl.co.uk/SSHP/mini/mini70s.html|archive-date=27 September 2007}}</ref> The [[Signals Research and Development Establishment]] (SRE) led the development, and performed initial in-orbit testing. Subsequently, the Royal Signals and Radar Establishment supported Skynet satellites, including developing ground terminals and modems, at [[RAF Defford]] which was also a backup for the primary ground station at [[RAF Oakhanger]].<ref name=mraths-201807/> The Skynet 2B system was very successful for its time, and remained in service for 20 years although only having 2 communications channels.<ref name=rafmuseum-20170630>{{cite web|url=https://www.rafmuseum.org.uk/blog/the-original-skynet/|title=The Original Skynet|last=Day|first=Belinda|publisher=Royal Air Force Museum|date=30 June 2017|archive-url=https://web.archive.org/web/20190902104848/https://www.rafmuseum.org.uk/blog/the-original-skynet/|archive-date=2 September 2019}}</ref>

=== Skynet 3 ===
Skynet 3 series satellites was cancelled as the United Kingdom withdrew [[East of Suez]], and instead the capability it was intended to offer was delivered via U.S. and [[NATO]] assets.<ref name=rafmuseum-20170630/><ref name=rsre-198901/> This dependence on U.S. assets was identified as a weakness during the [[Falklands War]] and was one of the contributing factors for the emergence of the Skynet 4 series satellites tranche of space vehicles. Technology improvements created the possibility of tactical satellite communications using smaller terminals, creating a new requirement beyond Skynet 3 strategic headquarters communications.<ref name=mraths-skynet-201807/><ref>{{cite journal|title=UK Military Space Programmes, Whitehall Papers Volume 35, Issue 1, 1996|journal=Whitehall Papers|volume=35|pages=30–43|year= 1996|doi=10.1080/02681309609414784}}</ref> The [[Royal Navy]] was also concerned that the high frequency radio alternative enabled location tracking by the Soviet Union Ocean Surveillance System.<ref name=na-20191024>{{cite web|url=https://blog.nationalarchives.gov.uk/skynet-the-real-communication-satellite-system/|title=Skynet: the real communication satellite system|last=Mitchell|first=Keith|publisher=National Archives|date=24 October 2019|access-date=26 January 2021}}</ref>

=== Skynet 4 ===
[[File:Skynet 4, drawing.png|thumb|upright=1.0|right|Drawing of Skynet 4 in orbit]]
[[File:Soldier Operating Satellite Dish MOD 45102198.jpg|thumb|upright=1.0|right|Soldier adjusting a [[British Army communications and reconnaissance equipment#Small SATCOM|small SATCOM]] ground terminal to Skynet in 2000]]

Skynet 4 series satellites have few similarities to the earlier generations, being based on the [[British Aerospace]] [[European Communications Satellite]].<ref name=rsre-198901/> The cylindrical body of Skynet 1 and 2 was replaced by a large square body housing antennas with deployable solar-cell arrays. This marks the technological improvement from [[spin-stabilisation]], used in earlier cylindrical satellites, to [[three-axis stabilisation]] using [[momentum wheel]]s and [[reaction wheels]] controlling the satellite gyroscopically. Each satellite had a design operational life of 7 years.<ref name=rafmuseum-20170630/>

Skynet 4 manufacture was carried out by [[BAe Dynamics|British Aerospace Dynamics]] (BAe Dynamics) with [[Matra Marconi Space]] (MMS) providing the Communications payload. [[NATO]] adapted the design for the [[NATO Communications and Information Systems Services Agency|NATO IVA and IVB communication satellites]], also manufactured by BAe Dynamics.<ref name=rsre-198901/> The programme timescales were delayed, as initially Skynet 4 was designed to be launched from the [[Space Shuttle]] (STS), with chosen RAF officers to be part of each Shuttle Crew. However, following the 1986 [[Space Shuttle Challenger disaster|Challenger disaster]] ([[STS-51-L|STS 51-L]]), the programme slowed and all the Skynet 4 series satellites had to be modified to suit the changes needed to go on a disposable launch vehicle. As '''Skynet 4A''' build was advanced it needed significant modification, and its completion was overtaken by '''Skynet 4B''' which had not progressed as far, and hence more easily converted. Consequently, Skynet 4B was finished first and launched in 1988, with Skynet 4A next in early 1990, and '''Skynet 4C''' later the same year.<ref>{{cite web|url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1990-001A|title=Display: Skynet 4A 1990-001A|publisher=NASA|date=13 April 2021|access-date=18 April 2021}} {{PD-notice}}</ref><ref>{{cite web|url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1990-079A|title=Display: Skynet 4C 1990-079A|publisher=NASA|date=13 April 2021|access-date=18 April 2021}} {{PD-notice}}</ref> As of 2022, Skynet 4C is still in operation, providing service to the U.S. [[Amundsen–Scott South Pole Station]] for up to six hours a day because its [[orbital inclination]] has increased to 10.3°.<ref name=uksaregister-202010/><ref name=usap-skynet>{{cite web|url=https://www.usap.gov/technology/4297/ |title=Skynet|publisher=National Science Foundation|work=United States Antarctic Program|access-date=26 January 2021}} {{PD-notice}}</ref><ref name=airbus-20170510>{{cite web|url=https://airbus-ds-gs.com/wp-content/uploads/2020/04/X-Band-brochure.pdf|title=X-Band for Mission Critical Communications|publisher=Airbus|date=10 May 2017|access-date=21 February 2021}}</ref><ref name=issuu-2022>{{cite news |url=https://issuu.com/dcdmagazine/docs/dcd-issue-43_print/s/14652040 |title=Antarctica comes in from the cold |last=Swinhoe |first=Dan |website=DCD Magazine |year=2022 |access-date=17 September 2022}}</ref>

The Stage 1 satellites (4A, 4B and 4C) have multi-frequency capability and considerable operational flexibility, with selectable channels, gain and four antenna types of differing widths to support varying requirements, [[Ultra high frequency]] (UHF), [[Super high frequency]] (SHF) and experimental [[Extremely high frequency]] (EHF) channels are available. They are hardening against [[electromagnetic pulse]] (EMP) and have anti-jamming capability, with an un-degraded 1600 watts [[power supply]]. The satellites have a dry mass of {{cvt|670|kg}}, with three [[reaction wheel]]s and [[hydrazine]] thrusters for station keeping.<ref name=rsre-198704>{{cite report|url=https://apps.dtic.mil/dtic/tr/fulltext/u2/a187005.pdf|archive-url=https://web.archive.org/web/20200325162641/https://apps.dtic.mil/dtic/tr/fulltext/u2/a187005.pdf|url-status=live|archive-date=25 March 2020|title=An Introduction to Military Satellite Communications|author=T. C. Tozer|publisher=Royal Signals and Radar Establishment|id=RSRE Memorandum 3976|date=April 1987|access-date=26 January 2021}}</ref>

The improved Stage 2 satellites (4D, 4E and 4F) were built by [[Matra Marconi Space]] and [[Astrium]] to replace the earlier versions. Improvements included increased power and resistance to electronic jamming. '''Skynet 4D''' was launched in 1998, '''Skynet 4E''' in 1999 and '''Skynet 4F''' in 2001.<ref>{{cite web|url=http://space.skyrocket.de/doc_sdat/skynet-4.htm|title=Skynet 4A, 4B, 4C, 4D, 4E, 4F |publisher=Gunter's Space Page|date=14 February 2019|access-date=18 April 2021}}</ref> Skynet 4D was parked in a non-operational [[supersynchronous orbit]] on 28 January 2008.<ref name=uksaregister-202010/>

Skynet 4 provides Ultra high frequency and Super high frequency services using Earth cover, wide area and spot beam coverage.<ref>{{cite book|title=Eavesdropping on the British Military|first=Michael |last=Cannon|publisher=Cara Press|location=Dublin, Eire|year=1994|page=105}}</ref>

=== Skynet 5 ===
[[File:Skynet 5D in orbit, CGI.jpg|thumb|upright=1.0|right|A CGI impression of Skynet 5D in orbit]]

Skynet 5 is the next generation of satellites, replacing the existing Skynet 4 Stage 2 satellites. It was contracted via [[Private Finance Initiative]] (PFI) to a partnership between 
[[Astrium|Paradigm Secure Communications]] and [[Astrium|EADS Astrium]], a European spacecraft manufacturer.<ref name=ijglobal-20060712>{{cite news |url=https://ijglobal.com/articles/30241/the-uk-mods-skynet-5-restructuring |title=The UK MoD's Skynet 5 restructuring |last=Berry |first=Edward |website=IJGlobal |date=12 July 2006 |access-date=25 May 2021}}</ref> EADS Astrium was responsible for the build and delivery of Skynet 5 series satellites in orbit, whilst subsidiary company Paradigm was responsible for the provision of service to the [[Ministry of Defence (United Kingdom)|Ministry of Defence]] (MoD). In 2010, the PFI contract was extended by two years to 2022, to a total cost of £3.66 billion over the course of the contract, with Paradigm able to sell bandwidth in excess of the capacity of 1.1 Skynet satellites to other allied countries.<ref name=independent-20100310>{{cite news |url=https://www.independent.co.uk/news/business/news/mod-extends-skynet-contract-1918959.html|title=MoD extends Skynet contract|last=Clark|first=Nick|newspaper=The Independent|date=10 March 2010|access-date=27 November 2020}}</ref><ref name=nao-20061124>{{cite report|url=https://www.nao.org.uk/wp-content/uploads/2006/11/060723i.pdf|title=Ministry of Defence - Major Projects Report 2006|id=HC 23-I|publisher=National Audit Office|pages=19–23|date=24 November 2006|access-date=27 November 2020}}</ref> Paradigm had 220 staff and about 100 sub-contractors working on Skynet.<ref name=pppforum-200911>{{cite web |url=https://www.pppforum.com/case-studies/skynet-5-0|title=Skynet 5|last=Peto|first=Malcolm|publisher=PPP Forum|work=Innisfree Group|date=November 2009|access-date=10 March 2021}}</ref> [[Serco]] is a major subcontractor on the PFI programme.<ref name=serco-stacoms>{{cite web|url=https://www.serco.com/uk/sector-expertise/defence/space-and-security/satcoms|title=Satcoms|publisher=Serco|access-date=10 March 2021}}</ref> This was the biggest ever outsourced military satellite communications contract.<ref name=rand-2017>{{cite report |url=https://www.rand.org/content/dam/rand/pubs/research_reports/RR1700/RR1786/RAND_RR1786.pdf|title=Defence and security after Brexit|last1=Black|first1=James|last2=Hall|first2=Alex|last3=Cox|first3=Kate |last4=Kepe|first4=Marta|last5=Silfversten|first5=Erik|publisher=RAND|doi=10.7249/RR1786|year=2017|access-date=13 March 2021}}</ref>

The Skynet 5 satellite is based on the [[Eurostar E3000]] [[satellite bus]] design, weighs about {{cvt|4700|kg}}, has two solar panels each about fifteen metres long, and has a power budget of five kilowatts. It has four steerable transmission dishes, and a phased-array receiver designed to allow [[radio jamming|jamming]] signals to be cancelled out. They will also resist attempts to disrupt them with high-powered lasers.<ref>{{cite news|url=http://news.bbc.co.uk/2/hi/science/nature/7079876.stm|publisher=BBC News|title=UK set for military space launch|date=9 November 2007|access-date=2008-06-13}}</ref><ref name=ukdj-20180521>{{cite news|url=https://ukdefencejournal.org.uk/what-is-skynet-a-look-at-britains-military-communications-satellites/|title=What is Skynet? A look at Britain's military communications satellites |last=Allison|first=George|publisher=UK Defence Journal|date=21 May 2018|access-date=26 January 2021}}</ref>

Astrium described in 2010 the Skynet 5 system as: {{Blockquote|The Skynet 5 satellites have the highest powered [[X band|X-band]] [[Transponder (satellite communications)|transponders]] in orbit, a highly flexible uplink beam configuration, coupled with a world leading anti-jamming antenna to ensure that the constellation is extremely effective against hostile or non-hostile interference. All of the downlink beams are fully steerable and the whole payload is optimized to maximise performance for small, rapidly deployable satellite ground terminals on land, sea or air.<ref name=defense-aerospace-20100309>{{cite press release |url=http://www.defense-aerospace.com/article-view/release/113025/astrium-wins-%C2%A3400m-contract-extension-for-fourth-skynet-5-satellite.html|title=Sky's the Limit for New Military Satellite - Paradigm Agrees Deal with UK Ministry of Defence (MoD) for Fourth Skynet 5 Satellite|website=defense-aerospace.com|publisher=Ministry of Defence and EADS Astrium|date=9 March 2010|access-date=5 April 2020}}</ref>}}

'''[[Skynet 5A]]''' was launched by an [[Ariane 5]] launch vehicle at 22:03 [[Coordinated Universal Time|UTC]] on 11 March 2007, in a launch shared with the Indian [[Indian National Satellite System|INSAT 4B]] civil communications satellite, and entered full service on 10 May 2007.<ref name=astrium-20070510>{{cite press release|url=http://www.astrium.eads.net/press-center/press-releases/astrium-triple-success-as-skynet-5a-enters-full-service|title=Astrium triple success as Skynet 5A enters full service|publisher=EADS Astrium|date=10 May 2007|archive-url=https://web.archive.org/web/20070523224556/http://www.astrium.eads.net/press-center/press-releases/astrium-triple-success-as-skynet-5a-enters-full-service|archive-date=23 May 2007}}</ref> The launch was delayed from 10 March 2007 due to malfunction of a launch pad deluge system.<ref>{{cite news|url=http://news.bbc.co.uk/1/hi/sci/tech/6434773.stm|publisher=BBC News|title=British Skynet satellite launched |date=12 March 2007|access-date=2008-06-13}}</ref> Skynet 5A successfully separated from its launch vehicle and telemetry was acquired by its dedicated Control Centre approximately 40 minutes after launch.

'''[[Skynet 5B]]''' was launched at 22:06 UTC on 14 November 2007, from [[Guiana Space Centre|Centre Spatial Guyanais]], [[Kourou]], in [[French Guiana]], aboard an [[Ariane 5|Ariane 5ECA]] launch vehicle. This launch was delayed from 9 November 2007 due to problems with the electronics on one of the [[Solid rocket booster|Solid Rocket Boosters]] (SRB), and 12 November 2007 due to a fuelling problem with the launch pad. At time of launch, the Ariane 5ECA launcher set a new record on this mission, deploying a total payload of more than {{cvt|8700|kg}}.<ref>{{cite press release |url=http://www.arianespace.com/site/news/releases/presrel07_11_14_2.html|publisher=Arianespace|title=Arianespace boosts Skynet 5B and Star One C1 into orbit: Sets new record|date=14 November 2007|access-date=2008-06-13|url-status=dead|archive-url=https://web.archive.org/web/20080617134817/http://www.arianespace.com/site/news/releases/presrel07_11_14_2.html|archive-date=17 June 2008}}</ref>

'''[[Skynet 5C]]''' was launched at 22:05:09 UTC on 12 June 2008, from Centre Spatial Guyanais, Kourou, in French Guiana, aboard an Ariane 5ECA launch vehicle.<ref>{{cite press release
|url=https://www.arianespace.com/press-release/successful-dual-launch-for-arianespace-skynet-5c-and-turksat-3a-in-orbit-25th-successful-launch-in-a-row-for-ariane-5/|title=Successful dual launch for Arianespace: Skynet 5C and Turksat 3A in orbit; 25th successful launch in a row for Ariane 5|date=12 June 2008|access-date=2023-04-08|publisher=Arianespace}}</ref> The launch had been delayed twice. Originally scheduled for 23 May 2008, more checks were carried out on the launch vehicle and the launch was rescheduled for 30 May 2008.<ref>{{cite press release|url=http://www.arianespace.com/site/news/releases/presrel08_05_14.html|title=Arianespace Flight Skynet 5C – Turksat 3A: Liftoff rescheduled for the night of May 30, 2008|date=14 May 2008|access-date=2008-06-13|publisher=Arianespace|url-status=dead|archive-url=https://web.archive.org/web/20080530212914/http://www.arianespace.com/site/news/releases/presrel08_05_14.html|archive-date=30 May 2008}}</ref> A problem with the launch software during pre-launch checks led Arianespace to reschedule the launch for a second time to 12 June 2008.<ref>{{cite press release|url=https://www.arianespace.com/press-release/arianespace-launch-with-skynet-5c-and-turksat-3a-launch-postponed/|title=Arianespace launch with Skynet 5C and Turksat 3A: launch postponed|date=30 May 2008|access-date=2023-04-08|publisher=Arianespace}}</ref><ref>{{cite news |url=https://www.spacedaily.com/reports/Ariane_Skynet_5C_And_Turksat_3A_Launch_Delayed_To_June_12_999.html|title=Ariane Skynet 5C And Turksat 3A Launch Delayed To June 12|date=10 June 2008|access-date=2023-04-08|website=spacedaily.com}}</ref>

'''[[Skynet 5D]]''' was launched at 21:49:07 UTC on 19 December 2012, from Centre Spatial Guyanais, Kourou, in French Guiana, aboard an Ariane 5ECA launch vehicle. Skynet 5D provides more than double the UHF channels of the previous satellites, which are in demand as they support "comms on the move" for soldiers with backpack radios.<ref name=bbc-20121219>{{cite web|title=UK's Skynet military satellite launched |url=https://www.bbc.co.uk/news/science-environment-20781625|date=2012-12-19|access-date=2012-12-20|publisher=BBC News}}</ref> The Ministry of Defence described the satellite as having a "key role in gathering intelligence on operations", as well as communications.<ref name=defense-aerospace-20100309/> Skynet 5D has larger fuel tanks enabling it to be repositioned more frequently if necessary.<ref name=sn-20130416/>

The programme marks a change of approach in the UK from traditional defence procurement methods to a services-based contract which also includes provision of leased ground terminals, ''Reacher'' vehicles, the ''Satellite Communications Onboard Terminal'' (SCOT) for ships, and the associated baseband equipment.<ref name=davison-2013>{{cite journal |title=A SPAR Modelling Platform Case Study: Skynet 5|last1=Davison|first1=Iain|last2=Miles|first2=Ian|journal=Procedia Cirp |publisher=Elsevier|doi=10.1016/j.procir.2013.07.001|year=2013|volume=11|pages=431–434|doi-access=free}}</ref>

Initially two Skynet 5 satellites were to be built, with insurance covering any launch loss; the MoD later decided to have a third satellite built in advance, and later still to have the third satellite launched to serve as an on-orbit spare, as well as an option to a fourth satellite, as a cheaper alternative to insurance.<ref name=pppforum-200911/><ref>{{cite news |url=http://news.bbc.co.uk/1/hi/sci/tech/7419751.stm|title=Countdown to UK military launch|date=29 May 2008|access-date=2008-05-30|publisher=BBC News}}</ref>

In 2011, The MOD took ownership of a NATO satellite with two UHF channels, to support the additional demands from [[Operation Herrick|British involvement]] in the [[War in Afghanistan (2001–2021)|War in Afghanistan]]. Control of this satellite was incorporated into the Skynet 5 PFI contract.<ref name=mod-20110830>{{cite news |url=https://www.gov.uk/government/news/new-satellite-improves-communications-in-afghanistan |title=New satellite improves communications in Afghanistan |publisher=Ministry of Defence |via=gov.uk |date=30 August 2011 |access-date=14 July 2022}}</ref>

The satellites are managed from a site named Hawthorn, a few hundred metres north of [[MoD Corsham]], in partnership with MoD's [[Defence Digital]] (previously [[Information Systems & Services]]) who are based at MoD Corsham.<ref name=desider-201111>{{cite report|url=https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/33822/desider_42_Nov2011v2_0.pdf|title=Reacher is a highlight of Paradigm factfinder|page=17|publisher=Defence Equipment and Support|work=desider|issue=42|date=November 2011|access-date=11 February 2019}}</ref>

==== Expansion to near global coverage ====
In 2010, Paradigm announced it would lease the [[X band|X-band]] (SHF) module on the [[Anik (satellite)#Anik G1|Anik G1]] commercial satellite at 107.3° West over the [[Pacific Ocean]], covering the [[Americas]] and as far west as [[Hawaii]], to complement Skynet system coverage. The three-channel, wide-beam X-band payload has performance similar to a Skynet 5 satellite, but without the military hardening.<ref name=sn-20101013>{{cite news|url=https://spacenews.com/paradigm-secures-all-anik-g1s-x-band-capacity/|title=Paradigm Secures All of Anik G1's X-band Capacity|author=Peter B. de Selding|publisher=SpaceNews |date=13 October 2010|access-date=20 February 2021}}</ref> Anik G1 launched on 16 April 2013, improving the constellation's X-band capacity to 2.2 [[Hertz|GHz]] of throughput.<ref name=sn-20130416>{{cite news |url=https://spacenews.com/34873newly-launched-anik-g1-to-provide-revenue-boost-for-telesat/|title=Newly Launched Anik G1 To Provide Revenue Boost for Telesat|author=Peter B. de Selding|publisher=SpaceNews |date=16 April 2013|access-date=21 February 2021}}</ref><ref name=airbus-20170510/>

In 2015, Skynet 5A was moved from 6° East, where it reinforced [[Middle East]] coverage, to 95° East, near [[West Sumatra]]. This move was to extend the Skynet coverage eastward in the [[Indian Ocean]] and to the [[Pacific Ocean|western Pacific Ocean]]. With this move and Anik G1, Skynet offers near global coverage, from 178° West to 163° East.<ref name=mod-20150317>{{cite news |url=https://www.gov.uk/government/news/uk-to-deliver-secure-communications-with-new-satellite-move |title=UK to deliver secure communications with new satellite move |publisher=Ministry of Defence |via=gov.uk |date=17 March 2015 |access-date=14 July 2022}}</ref><ref name=ukspace-20160914>{{cite news |url=https://www.ukspace.org/airbus-expands-skynet-partner-network/|title=Airbus Defence and Space expands its Skynet channel partner network with three major military communication providers|publisher=UKspace |date=14 September 2016|access-date=20 February 2021}}</ref>

In 2016, a new Australian ground station was opened at [[Mawson Lakes]], [[Adelaide]], managed by Airbus in partnership with [[SpeedCast]], an Australian provider for over 25 years which works with the Australian military at that base. This complements Airbus's existing chain of ground stations in France, Germany, Norway, United Kingdom and the United States. The British High Commissioner [[Menna Rawlings]] said at the opening ceremony "Territorial disputes over uninhabited rocks and reefs have the potential to generate enough friction in international affairs to spark a confrontation", alluding to the [[territorial disputes in the South China Sea]].<ref name=abcau-20160516>{{cite news|url=https://www.abc.net.au/news/2016-05-16/skynet-satellite-ground-station-opens-in-adelaide/7419042|title=Skynet satellite ground station opens in Adelaide to aid UK military communications|last=MacLennan|first=Leah|publisher=ABC News|location=Australia|date=16 May 2016|access-date=20 February 2021}}</ref><ref name=defenceconnect-20160516>{{cite news|url=https://www.defenceconnect.com.au/intel-cyber/4-skynet-in-australia|title=Skynet in Australia|publisher=Defence Connect|date=16 May 2016 |access-date=20 February 2021}}</ref>

[[Airbus Defence and Space]] signed a further three partners, [[Hughes Network Systems]], [[Inmarsat]] and [[SpeedCast]], into its Skynet partner programme who offer third-party Skynet services. The Skynet contract also allow Airbus to sell surplus bandwidth to [[NATO]] and allied governments, including the [[Five Eyes]] intelligence alliance (Australia, Canada, New Zealand, the United Kingdom and the United States).<ref name=ukspace-20160914/><ref name=viasat-20150916>{{cite news|url=https://www.satellitetoday.com/government-military/2015/09/16/skynet-5a-satellite-arrives-at-asia-pacific-orbital-slot/ |title=Skynet 5A Satellite Arrives at Asia-Pacific Orbital Slot|last=Henry|first=Caleb|publisher=Access Intelligence|work=Via Satellite|date=16 September 2015|access-date=20 February 2021}}</ref>

==== Technical specifications ====
The fleet of military X-band satellites have been specifically designed to support smaller, low powered, tactical terminals. Each Skynet 5 satellite is equipped with:

* High power 160W [[Traveling-wave tube|TWTA]]s on all [[transponder]]s, giving 56 dBW peak [[Effective radiated power|EIRP]] in each transmit spot beam and 41 [[Decibel watt|dBW]] peak EIRP in each global beam per transponder
* 15 active [[Super high frequency|SHF]] / [[Extremely high frequency|EHF]] transponders ranging in bandwidth from 20&nbsp;GHz to 40&nbsp;GHz
* Up to 9 [[Ultra high frequency|UHF]] channels
* Multiple fully steerable downlink spot beams
* On Board Active Receive Antenna (OBARA) capable of generating multiple shaped uplink beams
* Flexible switching capability allowing connectivity between any uplink beam and at least two downlink beams
* Nuclear hardening, anti-jamming countermeasures and laser protection<ref>{{cite web|title=Skynet 5 System features|url=http://www.satcom-airbusds.com/products-solutions/government-satcom/products-systems/bandwidth/skynet-5-x-band/#benefits|url-status=dead|archive-url=https://web.archive.org/web/20140516082649/http://www.satcom-airbusds.com/products-solutions/government-satcom/products-systems/bandwidth/skynet-5-x-band/#benefits|archive-date=16 May 2014}}</ref>

=== Skynet 6 ===
[[File:Skynet 6A in orbit.jpg|thumb|An artist's impression of Skynet 6A in orbit]]
As of 2018, the MoD was specifying the replacement of Skynet 5, whose PFI programme ends in August 2022.<ref name=ukdj-20190212>{{cite news|url=https://ukdefencejournal.org.uk/skynet-6-private-sector-innovation-critical-to-meeting-uk-defence-satcom-needs/|title=Skynet 6: Private sector innovation "critical" to meeting UK defence SATCOM needs|last=Peterman|first=Ken|publisher=UK Defence Journal|date=12 February 2019|access-date=21 July 2019}}</ref><ref name=bbc-20200720>{{cite news|url=https://www.bbc.co.uk/news/science-environment-53476881|title=MoD contracts Airbus for Skynet telecoms satellite|last=Amos |first=Jonathan|work=BBC News|date=20 July 2020|access-date=30 October 2020}}</ref> Airbus Defence and Space will build a non-competitively sourced '''Skynet 6A''' satellite planned for a 2025 launch, as a transition to a new architecture.<ref name=spacenews-20181107>{{cite news|url=https://spacenews.com/hts-megaconstellations-feed-uk-indecisiveness-about-skynet-6-program/|title=HTS, megaconstellations feed UK indecisiveness about Skynet 6 program|last=Henry|first=Caleb|publisher=SpaceNews|date=7 November 2018|access-date=21 July 2019}}</ref><ref name=mod-20191022>{{cite web |url=https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/841624/20191022_-_Skynet_6_AOA.pdf|title=Accounting Officer Assessment - Skynet 6|last=Lovegrove |first=Stephen|publisher=Ministry of Defence|date=22 October 2019|access-date=19 April 2020}}</ref> As of 2017, the PFI project was viewed as unlikely to be extended, as PFI contracting was then seen as generally poor value for taxpayers, and it had depleted MoD of satellite expertise which made specifying its replacement difficult.<ref name=seradata-20171129>{{cite news|url=https://www.seradata.com/uk-mod-confirms-competition-for-proper-follow-on-to-skynet-5-after-award-to-airbus-for-skynet-6a-gapfiller/|title=UK MoD confirms competition for proper follow-on to Skynet 5 after award to Airbus for Skynet 6A gapfiller|last=Todd|first=David|publisher=Seradata|date=29 November 2017|access-date=21 July 2019}}</ref>

Skynet 6A is based on the Airbus [[Eurostar (satellite bus)|Eurostar Neo]] [[satellite bus]], using electric orbit raising and station keeping propulsion, and built at Airbus [[Stevenage]] and [[Portsmouth]], England. It uses more radio frequencies for communication, and will have more capacity and versatility than Skynet 5 satellites.<ref name=bbc-20200720/><ref name=airbus-20200719/> A contract for over £500 million was agreed in July 2020, including launch, testing and related ground operations improvements.<ref name=airbus-20200719>{{cite press release|url=https://www.airbus.com/newsroom/press-releases/en/2020/07/airbus-signs-contract-with-uk-ministry-of-defence-for-skynet-6a-satellite.html|title=Airbus signs contract with UK Ministry of Defence for Skynet 6A satellite|publisher=Airbus|date=19 July 2020|access-date=22 February 2021}}</ref><ref name=dn-20200720>{{cite news|url=https://www.defensenews.com/global/europe/2020/07/20/airbus-gets-630-million-deal-under-uk-militarys-skynet-6-push/|title=Airbus gets US$630 million deal under UK military's Skynet 6 push|last=Chuter|first=Andrew|agency=Gannett|publisher=DefenseNews|date=20 July 2020|access-date=22 February 2021}}</ref> Due to the delay in agreeing the Skynet 6A contract, preliminary contracts for initial design and to manufacture long lead items had been agreed earlier to prevent end-date slippage.<ref name=c4isrnet-20200522/><ref name=mod-20191022/> Manufacture of 6A started in October 2021, and a [[Falcon 9]] launch was booked with [[SpaceX]] for 2025.<ref name=news-20211013>{{cite news |url=https://news.satnews.com/2021/10/13/the-uk-mods-skynet-6a-milsatcom-satellite-production-is-initiated-by-airbus/ |title=The UK MOD's Skynet 6A MILSATCOM Satellite Production Is Initiated By Airbus |website=satnews |date=13 October 2021 |access-date=8 November 2021}}</ref><ref name=teslarati-20211102>{{cite news |url=https://www.teslarati.com/spacex-wins-skynet-launch-contract/ |title=SpaceX wins Skynet launch contract |last=Ralph |first=Eric |website=Teslarati |date=2 November 2021 |access-date=8 November 2021}}</ref>

The vision for Skynet 6 is a flexible system architecture that combines UK government, allied and commercial satellites. The MoD has become a user of U.S. military constellations [[Advanced Extremely High Frequency]] (AEHF) and the [[Wideband Global Satcom]] (WGS) systems, and may become a partner in the [[Mobile User Objective System]] (MUOS).<ref name=spacenews-20181106>{{cite news |url=https://spacenews.com/u-k-mod-still-undecided-on-how-to-procure-satellite-communications/|title=UK MoD still undecided on how to procure satellite communications|last=Erwin|first=Sandra|publisher=SpaceNews |date=6 November 2018|access-date=21 July 2019}}</ref><ref name=sn-20181107>{{cite news|url=https://spacenews.com/hts-megaconstellations-feed-uk-indecisiveness-about-skynet-6-program/|title=HTS, megaconstellations feed UK indecisiveness about Skynet 6 program|last=Henry|first=Caleb|publisher=SpaceNews|date=7 November 2018|access-date=22 February 2021}}</ref> Part of the enhanced capability would be to support data links to [[unmanned aerial vehicle]]s and [[F-35B Lightning II]] aircraft.<ref name=ukdj-20190913>{{cite news|url=https://ukdefencejournal.org.uk/skynet-6-british-military-satellite-project-receives-boost/|title=SKYNET 6 British military satellite project receives boost|last=Allison|first=George|publisher=UK Defence Journal|date=13 September 2019|access-date=10 April 2020}}</ref><ref name=cbr-20190912>{{cite news|title=Who Wants to Run SKYNET 6? Gov't Says £6 Billion in Contracts is Landing Soon|last=Reynolds|first=Conor|publisher=Computer Business Review|date=12 September 2019}}</ref>

As of 2019, Skynet is the large part of the MoD Future Beyond Line of Sight Satellite Communications programme (FBLOS), which extends to 2041, and has four elements:<ref name=mod-20191022/><ref name=nao-202012>{{cite report|page=18|url=https://www.nao.org.uk/wp-content/uploads/2020/12/Departmental.Overview.2019-20.Ministry.of_.Defence.pdf|title=Departmental Overview 2019-2020 - Ministry of Defence|id=DP Ref: 008063-001|publisher=National Audit Office|date=December 2020|access-date=22 February 2021}}</ref>
* Skynet 6A, a single transition satellite
* Service Delivery Wrap, a support contract to manage and control the Skynet constellation and ground infrastructure
* Skynet 6 Enduring Capability, to provide and operate communication satellites and ground infrastructure into the future
* Secure Telemetry, Tracking and Command (STT&C), to provide assured UK control and management of satellites and their payloads into the future

On 3 July 2020, the UK Government announced that it had acquired a 45% stake in the [[OneWeb]] [[low Earth orbit]] satellite communications company, for US$500 million including a golden share to give it control over any future ownership sale.<ref name=bbc-20200703>{{cite news|url=https://www.bbc.co.uk/news/science-environment-53279783|title=UK government takes £400m stake in satellite firm OneWeb|publisher=BBC News|date=3 July 2020|access-date=30 October 2020}}</ref> Analysts believe OneWeb will be incorporated into the Skynet 6 architecture. OneWeb satellites are already manufactured by a joint venture including Airbus Defence and Space, which positions the current Skynet operator well for future involvement in Skynet 6.<ref name=sn-20200719>{{cite news |url=https://spacenews.com/british-military-finalizes-skynet-6a-contract-with-airbus/|title=British military finalizes Skynet-6A contract with Airbus|last=Henry|first=Caleb|publisher=SpaceNews|date=19 July 2020|access-date=30 October 2020}}</ref><ref name=ft-20200702>{{cite news|url=https://www.ft.com/content/597f0bb4-d3d2-4d70-a972-8021dbf6f241 |archive-url=https://ghostarchive.org/archive/20221210/https://www.ft.com/content/597f0bb4-d3d2-4d70-a972-8021dbf6f241 |archive-date=10 December 2022|title=UK gamble on OneWeb signals more interventionist space policy|last=Hollinger|first=Peggy|newspaper=Financial Times|url-access=subscription|date=2 July 2020|access-date=21 November 2020|quote="The real end game here is SkyNet", said one industry executive, referring to the military grade constellation that for 17 years has been operated by Airbus, and whose contract is soon coming to an end.}}</ref>

In 2021, a one-year transition was expected to start from the Airbus PFI contract to the new Service Delivery Wrap contract which will operate ground stations until a new generation of satellites under an Enduring Capability contract are launched from about 2028. This transition is expected to cost about £6 billion.<ref name=c4isrnet-20200522>{{cite news|url=https://www.c4isrnet.com/battlefield-tech/space/2020/05/22/uk-nears-final-stage-of-skynet-competition/|title=UK nears final stage of Skynet competition|last=Chuter|first=Andrew|website=c4isrnet.com|publisher=Sightline Media|date=22 May 2020 |access-date=22 February 2021}}</ref>

In February 2023, [[Babcock International]] won the Service Delivery Wrap support contract to operate and manage Skynet, including the ground infrastructure and integrating new user terminals, for six years from March 2024 at a cost of £400 million.<ref name=dn-20230215>{{cite news |url=https://www.defensenews.com/global/europe/2023/02/15/babcock-wins-480-million-bid-to-run-britains-skynet-satcom-program/ |title=Babcock wins $480 million bid to run Britain's Skynet SATCOM program |last=Chuter |first=Andrew |publisher=Gannett |work=DefenseNews |date=15 February 2023 |access-date=22 April 2023}}</ref><ref name=mod-20230215>{{cite press release |url=https://www.gov.uk/government/news/400-million-contract-to-operate-military-satellite-communications-system-supports-400-uk-jobs |title=£400 million contract to operate military satellite communications system supports 400 UK jobs |publisher=Ministry of Defence |via=gov.uk |date=15 February 2023 |access-date=22 April 2023}}</ref>

During 2023 contractors were preparing to bid on the SkyNet Enduring Capability programme, which is split into two contracts: the major one to deliver a constellation of up to three geostationary wideband satellite systems for launch from 2028-2030, and a smaller contract for a narrowband service for tactical battlefield access.<ref name=ft-20231023>{{cite news |url=https://www.ft.com/content/a92ce339-eb82-4a3c-b6e6-a18db5e58af6 |title=Airbus signs up Northrop Grumman in bid for SkyNet military satellite contract |last=Pfeifer |first=Sylvia |newspaper=Financial Times |url-access=subscription |date=23 October 2023 |access-date=17 November 2023}}</ref><ref name=mod-20230531>{{cite web |url=https://www.contractsfinder.service.gov.uk/Notice/70e8989c-506a-4c54-8248-447a9f95c8b4 |title=Skynet Enduring Capability wideband satellite system pre-PQQ |via=gov.uk |publisher=Ministry of Defence |date=31 May 2023 |access-date=17 November 2023}}</ref>

== Information assurance ==
In early 1999, [[Reuters]] reported that the Skynet system was breached by a group of hackers who issued blackmail threats against the MoD. [[Duncan Campbell (investigative journalist)|Duncan Campbell]] reported that the wire reports were wrong.<ref>{{cite news|url=https://www.theguardian.com/uk/1999/may/20/military.defence|title=Cyber Sillies|author=Duncan Campbell|date=20 May 1999|access-date=2008-02-19
|newspaper=The Guardian}}</ref>

== Satellite summary ==
{| class="wikitable"
|+'''Summary'''
|-
!Model
!Manufacturer
!Launch date
!Launch vehicle
!End of service<ref name=airbus-20181118>{{cite web|url=https://slideplayer.com/slide/14624068/|title=SKYNET Operations and Space Weather|last=Swinburne|first=Brian|work=Airbus Defence & Space|date=18 November 2018|access-date=26 January 2021}}</ref>
!GSO position in 2017<ref name=airbus-20170510/>
!Comments
|-
!colspan="7" align="center"|Skynet 1
|-
|align="center"|1A
|[[Philco Ford]]
|22 November 1969
|[[Delta M]]
|1971
|''105° West''
|Non-operational, not re-orbited<ref name=uksaregister-202010>{{cite report |url=https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/925088/UK_Registry_of_Space_Objects_October_2020.pdf|title=UK Registry of Outer Space Objects|publisher=UK Space Agency|date=October 2020|access-date=9 January 2021}}</ref>
|-
|align="center"|1B
|Philco Ford
|19 August 1970
|Delta M
|colspan=2 align=center|''launch failure''
|[[Apogee motor]] failure, did not orbit<ref name=uksaregister-202010/>
|-
!colspan="7" align="center"|Skynet 2
|-
|align="center"|2A
|[[Matra Marconi Space|Marconi Space Systems]]
|19 January 1974
|[[Delta 2000]]
|colspan=2 align=center|''launch failure''
|Rocket guidance failure, re-entry on 25 January 1974<ref name=uksaregister-202010/>
|-
|align="center"|2B
|Marconi Space Systems
|23 November 1974
|Delta 2000
|~1994<ref name=rafmuseum-20170630/>
|''~8° East''
|Uncontrolled, not re-orbited<ref name=uksaregister-202010/>
|-
!colspan="7" align="center"|Skynet 4 Stage 1
|-
|align="center"|4A
|[[British Aerospace]]
|1 January 1990
|[[Commercial Titan III]]<ref name=gunter-skynet4>{{cite web|url=https://space.skyrocket.de/doc_sdat/skynet-4.htm|title=Skynet 4A, 4B, 4C, 4D, 4E, 4F|last=Krebs|first=Gunter|publisher=Gunter's Space Page |date=14 February 2019|access-date=18 April 2021}}</ref>
|2005
|{{ndash}}
|Launched with [[JCSAT-2]], re-orbited in supersynchronous orbit on 20 June 2005<ref name=uksaregister-202010/>
|-
|align="center"|4B
|British Aerospace
|11 December 1988
|[[Ariane 4|Ariane 44LP]]
|1998
|{{ndash}}
|Launched with [[Astra 1A]], re-orbited 150&nbsp;km above GSO in June 1998<ref name=uksaregister-202010/>
|-
|align="center"|4C
|British Aerospace
|30 August 1990
|Ariane 44LP
|
|33° East
|From about 2017 providing service to the [[Amundsen–Scott South Pole Station]]<ref name=usap-skynet/>
|-
!colspan="7" align="center"|Skynet 4 Stage 2
|-
|align="center"|4D
|[[Matra Marconi Space]]<ref group=note>Marconi Space Systems merged to form [[Matra Marconi Space]] in 1990. MMS acquired [[British Aerospace Space Systems|BAe Space Systems]] in 1994</ref>
|10 January 1998
|[[Delta II|Delta 7000]]
|2008
|{{ndash}}
|Replaced 4B, re-orbited in a supersynchronous orbit on 28 January 2008<ref name=uksaregister-202010/>
|-
|align="center"|4E
|Matra Marconi Space
|26 February 1998
|[[Ariane 4|Ariane 44L]]
|
|6° East
|
|-
|align="center"| 4F
|[[Astrium]]<ref group=note>In 2000 MMS merged with [[DaimlerChrysler Aerospace|DASA's]] space division to form [[Astrium]].</ref>
|7 February 2001
|Ariane 44L
|
|34° West
|
|-
!colspan="7" align="center"|Skynet 5
|-
|align="center"|[[Skynet 5A|5A]]
|[[EADS Astrium]]<ref group=note>[[BAE Systems]] sold its 25% share of Astrium, renamed EADS Astrium</ref>
|11 March 2007
|[[Ariane 5|Ariane 5ECA]]
|
|95° East (prev. 6° East)
|Launched with [[Insat]] 4B. Moved in 2015 to extend Skynet coverage eastward to the western Pacific.<ref name=ukspace-20160914/>
|-
|align="center"|[[Skynet 5B|5B]]
|EADS Astrium
|14 November 2007
|Ariane 5ECA
|
|25° East (prev. 53° East)<ref name=uksaregister-202010/>
|Launched with Star One C1
|-
|align="center"|[[Skynet 5C|5C]]
|EADS Astrium
|12 June 2008
|Ariane 5ECA
|
|17.8° West
|Launched with Turksat 3A
|-
|align="center"|[[Skynet 5D|5D]]
|EADS Astrium
|19 December 2012
|Ariane 5ECA
|
|53° East
|Launched with [[MEXSAT-3]]
|-
!colspan="7" align="center"|Skynet 6
|-
|align="center"|6A
|[[Airbus Defence and Space]]
|''planned 2025''
|''[[Falcon 9 Block 5]]''<ref name=teslarati-20211102/>
|
|
|
|}

== See also ==
{{Portal|Spaceflight}}

* [[British Army communications and reconnaissance equipment#Satellite communications|British Army communications and reconnaissance equipment § Satellite communications]]
* [[British space programme]]
* [[Defence Intelligence Fusion Centre]]
* [[Defense Satellite Communications System]]
* [[Reacher Satellite Ground Terminal]]
* [[Syracuse (satellite)]]
* [[TACOMSAT]]

== Notes ==
{{reflist|group=note}}

== References ==
{{Reflist}}

== External links ==
* {{Commons category-inline}}
* {{Wiktionary-inline}}
* [https://securecommunications.airbus.com/ Airbus Secure Communications]
* [http://space.skyrocket.de/doc_sdat/skynet-2.htm www.skyrocket.de]
* [https://web.archive.org/web/20050812074832/http://www.astronautix.com/project/skynet.htm www.astronautix.com]
* [https://web.archive.org/web/20050204185158/http://www.astrium.eads.net/corp/file/part2/index.htm Astrium Ltd - manufacturer]
* [https://web.archive.org/web/20110917122539/http://www.paradigmsecure.com/ Paradigm Secure Communications]
* [https://www.secret-bases.co.uk/secret2.htm?permalink=skynet UK Skynet ground terminal locations]
* [https://satlaunch.org/database-m-s.htm Satlaunch.org - Satellites M to S] {{Webarchive|url=https://web.archive.org/web/20200323141327/https://satlaunch.org/database-m-s.htm |date=23 March 2020 }}
* {{cite web|url=https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/33691/SpacePrimerFinalWebVersion.pdf|title=The UK Military Space Primer|publisher=Ministry of Defence|date=June 2010}}

{{Skynet}}

[[Category:1969 establishments in the United Kingdom]]
[[Category:Military communications of the United Kingdom]]
[[Category:Military satellites of the United Kingdom]]
[[Category:Space programme of the United Kingdom]]
[[Category:Communications satellites of the United Kingdom]]