View source for Ballistic Missile Early Warning System

{{Short description|US Cold War Early Warning Radar for ballistic missile defense}}
{{Use dmy dates|date=January 2025}}{{Use American English|date=January 2025}}
{{For|preceding northern radar networks for detecting Soviet bombers|Pinetree Line|Mid-Canada Line|DEW Line}}
{{Infobox military installation
| name          = Ballistic Missile Early Warning System
| type          = Radar network
| image         = Ballistic Missile Early Warning System at Clear AFS (diagram).png
| image_size    = 300px
| caption       = Sketch of [[Clear Space Force Station]] BMEWS radars{{efn|Replaced by a [[Solid State Phased Array Radar System]]<ref>{{cite news |url= http://www.thefreelibrary.com/RAYTHEON+WINS+AIR+FORCE+CONTRACT+FOR+RADAR+AND+COMMUNICATIONS+SITES-a015800654 |title= Raytheon wins Air Force Contract for Radar and Communications Sites (Press Release) |publisher= Raytheon via thefreelibrary.com |date= September 7, 1994 |access-date= March 11, 2014 |archive-date= March 11, 2014 |archive-url= https://web.archive.org/web/20140311180821/http://www.thefreelibrary.com/RAYTHEON+WINS+AIR+FORCE+CONTRACT+FOR+RADAR+AND+COMMUNICATIONS+SITES-a015800654 |url-status= dead }}</ref> constructed April 16, 1998 – February 1, 2001.<ref>{{cite web |title=AN/FPS-120 Solid State Phased-Array System [SSPARS]: Clear Radar Upgrade |url=http://www.globalsecurity.org/space/systems/sspars.htm |publisher=GlobalSecurity.org |access-date=March 8, 2014}}</ref><ref>{{cite web |title=Clear AFS, AK |url=http://www.globalsecurity.org/space/facility/clear.htm |publisher=GlobalSecurity.org |access-date=March 5, 2014}}</ref>}}
| country       = United States
| location      = [[BMEWS Central Computer and Display Facility]]
| coordinates   = 
| fate          = Replaced in 2001 by [[Solid State Phased Array Radar System|SSPARS]]
*{{coord|38|50|23|N|104|47|44|W|display=inline}} [[Ent Air Force Base|in Colorado]]
*Site I:{{efn|name=fn1|Air Defense Command radar stations ([[cf.]] [[List of USAF Aerospace Defense Command General Surveillance Radar Stations|ADC general surveillance stations]])}} {{coord|76.569|N|68.318|W}} [[Thule Air Base|in Greenland]]
*Site II:{{efn|name=fn1}}{{coord|64.2561|N|149.1855|W}} [[Clear AFS|in Alaska]] ([[71st Missile Warning Wing|71st Det 2]]<ref>{{cite web |title=Remembering Our Heritage 25 June - 1 July |url=http://www.alaskawingcaf.org/Alaska%20Heritage/June%2025%20-%20July%201.pdf |publisher= Office of History, Elmendorf AFB via AlaskaWingCAF.org |access-date=5 November 2016 |quote=...facilities to accommodate the radar came to $62 million. More than 1,100 workers worked on the project. It involved excavating 185,000 cubic yards of dirt and gravel and the pouring of 65,000 yards of concrete. Materials totaled 4,000 tons of structural steel, 2,600 tons of reinforcing steel and 900,000 square feet of fabricated panels.<!-- Sources cited within that work (Miller, Hist, AAC, 1961, p. 484; Miller, Hist, AAC, Jan-Jun 1965, p. 175; E-mail, subj: Clear BMEWS, USAF Space Command History Office to 3rd Wing History Office, 25 Jun 2001.)-->}}</ref>)
*Site III: {{coord|54.3616|N|0.6697|W}} [[RAF Fylingdales|in Yorkshire]] ([[71st Missile Warning Wing|71st Det 1]]<ref>{{Cite journal |date=August 1967 |title=FYLINGDALES: Home of the Number One BMEWS Detachment |url=http://www.radomes.org/museum/parsehtml.php?html=BMEWSSite3RAFFylingdalesUKarticle.html&type=doc_html |format=image copy at Radomes.org |journal=Q Point |publisher=[[9th Aerospace Defense Division]] |access-date=5 March 2014}}</ref>)
*{{coord|10|44|34|N|61|36|29|W}} [[Chaguaramas, Trinidad|on Trinidad]]{{efn|site for [[:File:Tracking Station Dish, Trinidad and Tobago.jpg|FPS-50 prototype]]<ref name=StoneBanner>{{Cite report |author=Stone |author2=Banner |name-list-style=amp|title=Radars for the Detection and Tracking of Ballistic Missiles, Satellites, and Planets |url=https://www.ll.mit.edu/publications/journal/pdf/vol12_no2/12_2detectsatellitiesplanets.pdf |access-date=5 March 2014 |quote=The Millstone radar served as a development model for RCA's AN/FPS-49, AN/FPS-49A, and AN/FPS-92 radars, all of which were used in the BMEWS. Millstone was used to develop a fundamental understanding of several important environmental challenges facing the BMEWS. These challenges included the measurement of UHF propagation effects in the ionosphere, the impact of refraction close to the horizon, the effect of Faraday rotation on polarization, and the impact of backscatter from meteors and the aurora on the detection performance of the radar and its false-alarm rate [15–17]. In the early 1960s, the Millstone radar was converted from a UHF to an L-band system. The Air Force in the 1960s sponsored the development of Haystack, a versatile facility in Tyngsboro, Massachusetts, that supports radar- and radio-astronomy research and the national need for deep-space surveillance. |archive-url=https://web.archive.org/web/20130512191359/http://www.ll.mit.edu/publications/journal/pdf/vol12_no2/12_2detectsatellitiesplanets.pdf |archive-date=May 12, 2013 |url-status=dead }}</ref> (AN/FPS-43)<ref name=BMW>{{Cite book |author=Bate |author2=Mueller |author3=White |name-list-style=amp|year=1971 |orig-year=origyear tbd |title=Fundamentals of Astronautics |publisher=Courier Corporation |url=https://books.google.com/books?id=UtJK8cetqGkC&q=fps-92&pg=PA133 |format=Google books |access-date=5 March 2014 |quote=fan-shaped beams, about 1° in width and 3½° in elevation… The horizontal sweep rate is fast enough that a missile or satellite cannot pass through the fans undetected.|isbn=9780486600611 }}</ref>}}
*{{coord|39|58|49|N|74|54|04|W|notes=<ref>{{cite web |title=USS Rancocas: The Cornfield Cruiser |url=http://www.lockheedmartin.com/us/100years/stories/cornfield-cruiser.html |publisher=LockheedMartin.com |access-date=10 March 2014 |quote=Originally owned by the Air Force, the building was constructed in the 1950s. For years it was an Air Force-operated radar site, operating a ballistic missile early warning system. The warehouse-like gray building was topped by a radome...}}</ref>}} [[Moorestown, New Jersey|in New Jersey]] ([[9th Aerospace Defense Division|9th Det 3]]{{r|Det3}}){{efn|site for 1959–76<ref>{{cite web |last=Flack |first=John S. Jr |title=Moorestowns Giant Golf Ball |url=http://jsf1.homestead.com/MoorestownGolfBall.html |format=personal anecdote w/ photos |publisher= Personal web page on Homestead.com |access-date=10 March 2014 |quote=It was taken out of service in December, 1974 and dismantled in early 1976. After this, RCA built a replica of a [[USS Rancocas|US Navy cruiser deckhouse atop the building that the golf ball sat on for testing its Aegis Combat System and for training Navy personnel. The Aegis facility is still located here]], operated jointly by Lockheed Martin (which now operates the radar plant) and the Navy.}}</ref>{{unreliable source?|date=November 2016|reason=Unverifiable Personal webpage}} FPS-49 prototype<ref name=BMW /> and test/training{{r|Spring1963}}}}
| built         = 1958–1961<ref>{{cite web |url= https://www.loc.gov/pictures/item/ak0486/ |title= HAER AK-30-A - Clear Air Force Station, Ballistic Missile Early Warning System Site II |publisher= Historic American Engineering Record |date= 2003}}</ref> (complete FOC was 15 January 1964)<ref name=DelPapa />
| builder       = [[Radio Corporation of America|RCA Defense Electronics Products]]{{r|Spring1963}}{{rp|29}}{{efn|RCA was contracted in January 1958<ref name=NORAD1958>{{Cite NORAD Historical Summary |version=1958 |accessdate=April 22, 2013}}  NORAD looked at the Zl portion of the BMEWS not only as an integral portion of the system, but as the heart of the entire ballistic missile defense system.</ref> and employed 485 large companies and 2415 smaller firms spread over 29 states<ref>{{cite book|chapter-url= https://ethw.org/w/images/b/b5/100_Years_with_IEEE_in_the_Delaware_Valley_1984,_Part_1.pdf |chapter= The years 1958-1962 |first= E.W. |last= Engstrom |title= 100 Years With IEEE In The Delaware Valley, Part 1 |publisher= Philadelphia Section of IEEE |page= 16 |date= February 1984}}</ref> ($474,831,000 contract in February 1960; {{Inflation|index=US|value=474831000|start_year=1960|fmt=eq}})<ref>{{cite news |url= https://news.google.com/newspapers?nid=1300&dat=19600216&id=jX41AAAAIBAJ&pg=5178,2654670 |title= Big Missile-Warning System Outlay |newspaper= The Age |location= Melbourne |date=16 February 1960 |agency= [[Australian Associated Press]]}}</ref>}}
| footnotes     = 
}}

The '''RCA 474L Ballistic Missile Early Warning System''' ('''BMEWS''', '''474L System''',{{r|GlobalSecurity}} '''Project 474L''') was a [[United States Air Force]] [[Cold War]] [[early warning radar]], computer, and communications system,<ref>{{Cite book |title=The Closed World: Computers and the Politics of Discourse in Cold War America |first= Paul N. |last= Edwards |page= 107 |url=https://books.google.com/books?id=LkJgQOR4s4oC&pg=PA107 |format=Google Books |quote=SAGE—Air Force project 416L—became the pattern for at least twenty-five other major military command-control systems… These were the so-called "Big L" systems and included 425L, the NORAD system; 438L, the Air Force Intelligence Data Handling System; and 474L, the Ballistic Missile Early Warning System (BMEWS). … Project 465L, the [[Strategic Automated Command and Control System|SAC Control System]] (SACCS)|isbn= 9780262550284 |year= 1997 |publisher= MIT Press }}</ref> for [[ballistic missile]] detection. The network of twelve radars,<ref name=StoneBanner /> which was constructed beginning in 1958 and became operational in 1961, was built to detect a mass ballistic missile attack launched on northern approaches [for] 15 to 25 minutes' warning time<!--most probable through the 1963 time period--><ref>{{cite report |url= http://nsarchive.gwu.edu/NSAEBB/NSAEBB43/doc5.pdf |page= 5 |title= Report to the US Senate Preparedness Investigating Subcommittee on Warning and Detection systems |publisher= National Archives via nsarchive.gwu.edu |first= Robert |last= McNamara |date= November 3, 1961 }}</ref> also provided [[Project Space Track]]<ref>{{cite web|url=http://history.defense.gov/resources/1984_DoD_AR.pdf |title=Archived copy |access-date=March 11, 2014 |url-status=dead |archive-url=https://web.archive.org/web/20140311181652/http://history.defense.gov/resources/1984_DoD_AR.pdf |archive-date=March 11, 2014 }}</ref> satellite data (e.g., about one-quarter of [[Space Detection and Tracking System|SPADATS]] observations).<ref>{{cite book |url= https://books.google.com/books?id=cMgdYypcPc8C&pg=PA39 |title= High Frontier: The U.S. Air Force and the Military Space Program |first= Curtis |last= Peebles |page= 39|isbn= 9780788148002 |date= June 1997 |publisher= DIANE }}</ref>

It was replaced by the [[Solid State Phased Array Radar System]] in 2001.<ref name=Chapman>{{Cite book |last=Chapman |first=Bert |title=Space Warfare and Defense: A Historical Encyclopedia and Research Guide |year=2008 |publisher=Bloomsbury Academic |isbn=9781598840063 |url=https://books.google.com/books?id=Ae9f-7bV5w4C&q=%22Early+Warning+Radar%22+SSPARS&pg=PA153 |format=Google books |access-date=2014-03-13 |quote=BMEWS was replaced by the Solid State Phased Array Radar System (SSPARS) in 2001. ... CINCAD (Command in Chief, Aerospace Defense Command)}}</ref>

==Background==
The Ballistic Missile Early Warning System (BMEWS) was a radar system built by the [[United States]] (with the cooperation of [[Canada]] and [[Denmark]] on whose territory some of the radars were sited) during the [[Cold War]] to give early warning of a [[Soviet Union|Soviet]] [[intercontinental ballistic missile]] (ICBM) [[Nuclear warfare|nuclear strike]], to allow time for US bombers to get off the ground and land-based US ICBMs to be launched, to reduce the chances that a [[preemptive war|preemptive strike]] could destroy US strategic nuclear forces.

The shortest ([[great circle]]) route for a Soviet ICBM attack on North America is across the [[North Pole]], so the BMEWS facilities were built in [[Arctic|the Arctic]] at [[Clear Space Force Station]] in central [[Alaska]], and [[Thule Site J|Site J]] near [[Pituffik Space Base]], [[North Star Bay]], Greenland.  When it became clear in the 1950s that the Soviet Union was developing ICBMs, the US was already building an early-warning radar system in the Arctic, the [[DEW line]], but it was designed to detect bombers and did not have the capability of tracking ICBMs.

The challenges of designing a system that could detect and track a massive strike of hundreds of ICBMs were formidable. The radar sites were located as far north in the Arctic as possible, to give maximum warning time of an attack. However, the time between when a Soviet missile would rise above the horizon and be detected and when it would reach its target in the US was only 10 to 25 minutes.

== Equipment ==
BMEWS consisted of two types of radars and various computer and reporting systems to support them. The first type of radar consisted of very large, fixed rectangular partial-parabolic reflectors with two primary feed points. They produced two fan-shaped microwave beams that allowed them to detect targets across a very wide horizontal front at two narrow vertical angles. These were used to provide wide-front coverage of missiles rising into their [[radar horizon]], and by tracking them at two points as they climbed, enough information to determine their rough trajectory.

The second type of radar was used for fine tracking of selected targets, and consisted of a very large steerable parabolic reflector under a large [[radome]]. These radars provided high-resolution angular and ranging information that was fed to a computer for rapid calculation of the probable impact points of the missile warheads. The systems were upgraded several times over their lifetime, replacing the mechanically scanned systems with [[phased-array radar|phased array radar]] that could perform both roles at the same time.

[[File:Aerial view of clear AFS site, Official photograph BMEWS Project by C. Henry, 5 July 1962, Photographic Services, Riverton, NJ, BMEWS, clear as negative no. A-3945. - Clear Air Force HAER AK-30-A-96.jpg|thumb|Three of the huge AN/FPS-50 radars, BMEWS Site 2, near Anderson, Alaska, in 1962]]

BMEWS equipment included:<ref name=DoD1960>{{Cite report |year=1960 |title=Department of Defense Annual Report |chapter-url=http://www.mda.mil/global/documents/pdf/1960%20BMD%20extract.pdf |chapter-format=MDA.mil excerpt |chapter=Annual Report of the Secretary of Defense, The Armed Forces, pp. 14-15 ("Continental Air Defense" section) |access-date=March 6, 2014 |quote=The imminent shift in the air threat to our security from aircraft alone to ballistic missiles and aircraft led to [require] a reduction in the programs for the [[BOMARC]] missile and [[Super Combat Center|the hardened "supercombat" centers]] for the [[Semi-Automatic Ground Environment]] (SAGE) system, and an acceleration in the modernization of the fighter interceptor forces and in the construction of the Ballistic Missile Early Warning System (BMEWS) [with] three widely dispersed, long-range radar stations, a central computer and display facility in the United States, and a communications network to link the separate elements. |archive-date=February 19, 2013 |archive-url=https://web.archive.org/web/20130219034404/http://www.mda.mil/global/documents/pdf/1960%20BMD%20extract.pdf |url-status=dead }}</ref>
*'''General Electric AN/FPS-50''' Radar Set, a UHF (440&nbsp;MHz) detector with transmitter having an [[organ-pipe scanner]] feed, fixed 1,500 ton<ref>{{cite news |url= https://news.google.com/newspapers?nid=1310&dat=19600518&id=wv5VAAAAIBAJ&pg=6863,3516938 |title= Radar Net Nearing Completion |first= Elton C. |last= Fay |agency= AP |newspaper= Register-Guard |location= Eugene, Oregon |date= May 18, 1960 }}</ref> parabolic-torus reflector, and receiver with Doppler filter bank to scan with two horizontally-sweeping fans<ref name=StoneBanner /> for as many as ~12,000 observations per day<ref name=BMW /> for surveillance (determining range, position, and range rate) of space objects<ref>{{cite web |url= http://www.radomes.org/museum/equip/fps-50.html |title= FPS-50 |publisher= radomes.org }}</ref>
*'''RCA AN/FPS-49''' Radar Set, a five-horn monopulse tracker (e.g., three at Site III) and '''FPS-49A''' variant (different radome) at Thule<ref>{{cite web |title=AN/FPS-49, 49A |publisher= radomes.org |url=http://www.radomes.org/museum/equip/fps-49.html |access-date=March 5, 2014 |quote=The prototype unit operated at Moorestown, New Jersey}}</ref> (vacuum tubes 10 feet tall in transmitter buildings are used to warm the site)<ref>{{Cite news |date=January 4, 1961 |title=Thule's Electronic Sentinel |url=https://news.google.com/newspapers?nid=1499&dat=19610104&id=iuEpAAAAIBAJ&pg=4813,1400514 |format=Google news archive |newspaper=[[The Milwaukee Journal]] |access-date=March 9, 2014 }}{{Dead link|date=December 2024 |bot=InternetArchiveBot |fix-attempted=yes }}</ref>
*'''RCA AN/FPS-92''' Radar Set, an upgraded FPS-49 featuring more elaborate receiver circuits and hydrostatic bearings<ref name=BMW /> at Clear<ref>{{Cite web|url=http://www.radomes.org/museum/equip/fps-92.html|title=FPS-92|accessdate=June 25, 2023}}</ref>
*[[Sylvania Electric Products|Sylvania]] '''AN/FSQ-53''' Radar Monitoring Set, with console and Signal Data Converter Group<ref>{{cite web|url=http://radar.tpub.com/TM-11-487C-1/TM-11-487C-10192.htm |title=MONITORING SET, RADAR - continued - TM-11-487C-10192 |access-date=March 11, 2014 |url-status=dead |archive-url=https://web.archive.org/web/20140311180836/http://radar.tpub.com/TM-11-487C-1/TM-11-487C-10192.htm |archive-date=March 11, 2014 }}</ref> ("data take-off unit"){{citation needed|date=November 2016}}
*'''Sylvania AN/FSQ-28''' Missile Impact Predictor Set, with duplex [[IBM 7090|IBM-7090 TX solid-state computers]] e.g., in Building 2 at Thule <ref>{{cite web |url= https://groups.yahoo.com/neo/groups/coldwarcomms/conversations/topics/15618?var=1&p=5 |archive-url= https://archive.today/20140311153237/https://groups.yahoo.com/neo/groups/coldwarcomms/conversations/topics/15618?var=1&p=5 |url-status= dead |archive-date= March 11, 2014 |website= groups.yahoo.com |title= Cold War Comms Group forum}}</ref>{{unreliable source?|date=November 2016|reason=User Generated Content / Web forum group}} and part of the '''AN/FPA-21''' Radar Central Computer at Site III<ref>{{Cite report |title=title tbd |url=http://www.liberatedmanuals.com/TM-11-487C-1.pdf |access-date=March 7, 2014 |quote=Missile Impact Predictor Set AN/FSQ-28 accepts output of Radar Set AN/FPS-19 or AN/FPS-19A and Radar Set AN/FPS-50(V) to determine the trajectory of space objects and predicts the point of impact. Furnishes designation data to tracking Radar for enhancing target data accuracy. The AN/FSQ-28 is a duplex, general purpose computer (IBM-709-TX with real-time terminal and control equipment added).}}</ref>—Satellite Information Processor (SIP) software was later added at Site III for use on the backup IBM 7090.<ref>{{cite web|url=https://www.esrc.ac.uk/my-esrc/grants/R000238555/outputs/Download/623cc844-6b4d-4d58-a0da-2ef70b6cc202 |title=Archived copy |access-date=March 11, 2014 |url-status=dead |archive-url=https://web.archive.org/web/20140311193115/https://www.esrc.ac.uk/my-esrc/grants/R000238555/outputs/Download/623cc844-6b4d-4d58-a0da-2ef70b6cc202 |archive-date=March 11, 2014 }} the USA and UK agreed to be separately responsible for their own rearward data handling systems.’ [46] The UK systems were to meet Air Staff Requirement 2208 and called for ‘display of processed IRBM data at the Air Defence Operations Centre (ADOC), the Bomber Command Operations Centre (BCOC), the Air Ministry Operations Centre and, for standby purposes, at the Air Defence Main Control Centre and Headquarters No. 1 Group. The processed data will also be passed to NORAD over the USA rearward data handling system and this system</ref>
*'''RCA Communications Data Processor''' (CDP),<ref name=Gandy>{{cite book |title= The Early Computer Industry: Limitations of Scale and Scope |first= A. |last= Gandy |url= https://books.google.com/books?id=viDGg4_NvPQC&pg=PA48 |page= 48 |isbn= 9780230389113 |date= November 30, 2012 |publisher= Springer }}</ref> as used in the [[Western Electric]] Air Force Communications Network (AF DATACOM) of [[AUTODIN]]<ref name=Spring1963>{{Cite journal |last=Shore |first=Bruce |date=Spring 1963 |title=the fourth state of matter |journal=Electronics Age |publisher=RCA |quote=Several hundred RCA management, technical, and engineering personnel run the 80 control stations that make up [[White Alice Communications System|White Alice]], the country's largest over-the-horizon communications system. The stations, mostly on mountaintops, employ two types of antenna – one a 30-foot, disc-shaped structure and the other a 100-ton scoop-shaped unit 60 feet tall. The antennas relay signals from one to the other, sometimes over distances up to 170 miles. … In 1952, Mr. Heller led a group of RCA field engineers to a minor military installation at Cape Canaveral. From this simple beginning, the RCA Service Company became a subcontractor to [[Pan American Airlines|Pan American]] for the planning, systems engineering, operation, and maintenance of the vast complex instrumentation systems that constitute the Atlantic Missile Range.}}</ref>{{rp|21}}
*[[Western Electric]]<ref name=Moora>{{Cite journal |last=Moora |first=Robert L |date=Autumn 1960 |title=BMEWS Takes Shape…On Schedule: Greenland radar site begins early warning operations…|journal=Electronic Age |url=http://www.americanradiohistory.com/Archive-Radio-Age/ElectronicAge-1960-Autumn.pdf |access-date=March 6, 2014 |quote=a "data takeoff" computer translates the visual image into digital form, calculating distance, range, angle of flight, speed and direction. In split seconds, this data is on its way to a high-speed "missile impact predictor" computer. … prime system contractor is the Radio Corporation of America, with headquarters at the Missile and Surface Radar Division, Moorestown… Principal subcontractors to RCA include General Electric Company…}}</ref> '''BMEWS Rearward Communications System''', a network to link the separate elements{{r|DoD1960}}<ref>{{cite web |url= http://www.alternatewars.com/WW3/WW3_Documents/Fortifications/ABMWSP_Summary_23_Apr_1960.htm |title= ABMWSP Summary - 23 Apr 1960 |publisher= alternatewars.com World War III wargame alternative reality website |quote= Progress is satisfactory on the establishment of rearward communications from the forward sites to the Zone of the Interior display facilities at Colorado Springs, Colorado. On 1 December, through communication was established between the switchboard at Thule and the BMEWS Project Office in New York City. This tie line, together with a similar one between Thule and Westover Air Force Base, Massachusetts, represents the first use to be made of the submarine cable completed this last summer between Thule and Cape Dyer.}}</ref>{{unreliable source?|date=November 2016|reason=User Generated Content / WW3 wargaming - Is it real or part of the wargaming?}} and one of six ADC comm systems: BMEWS Rearward Long-Lines System<ref>{{cite report |url= http://claytwhitehead.com/ctwlibrary/Box%20018/001_Telecommunications%20(Domestic%20Satellite)%20October-December%201969%20(2%20of%203%20folders).pdf |title= Report of the Economic Committee on Domestic Satellites |publisher= US Office of Telecommunications Management via claywhitehead.com |first= Tom |last= Olsson |date= October 31, 1969 }}</ref> at [[CFS Resolution Island]]<ref name=Mitchell>{{cite web|last=Mitchell |first=Walt |title=Memories of Troposcatter at Resolution Island |url=http://www.c-and-e-museum.org/Pinetreeline/misc/other/misc3i.html |access-date=March 9, 2014 |quote=he BMEWS Rearward link came from Thule to Dye to [[Brevoort Island|ResX1]] to ResX on Resolution and then on to Goose Bay. I suspect that was the link maintained by Canadian Marconi under contract in the 1961 to 1974 period. |url-status=dead |archive-url=https://web.archive.org/web/20140311182756/http://67.69.104.76:84/Pinetreeline/misc/other/misc3i.html |archive-date=March 11, 2014 }}</ref>{{unreliable source?|date=November 2016|reason=User Generated Content / Web forum group}}<ref>{{cite web |url= http://archive-ca.com/ca/l/lswilson.ca/2013-04-28_1957995_7/DEW_Line_POL_Facilities/ |title= DEWDROP Troposheric Scatter AM Communications Link between Thule BMEWS and Cape Dyer |access-date= March 11, 2014 |archive-url= https://web.archive.org/web/20140311182919/http://archive-ca.com/ca/l/lswilson.ca/2013-04-28_1957995_7/DEW_Line_POL_Facilities/ |archive-date= March 11, 2014 |url-status= dead }}</ref> and [[CFS Saglek]],<ref>{{cite web|url=http://www.members.shaw.ca/johnbubb/index_files/bmews.htm |title=Tropospheric Scatter Communications Site Saglek Labrador Canada Circa 1969/70 |first= John |last= Bubb  |publisher= Personal Webpage at members.shaw.ca |access-date=March 11, 2014 |url-status=dead |archive-url= https://archive.today/20140311153219/http://www.members.shaw.ca/johnbubb/index_files/bmews.htm |archive-date=March 11, 2014 }}</ref>{{unreliable source?|date=November 2016|reason=User Generated Content / personal web page}} ([[cf.]] Pole Vault system on the [[Pine Tree Line|Pinetree Line]], [[White Alice Communications System|White Alice in Alaska]],{{r|Spring1963}} and to [[RAF Fylingdales]], [[North Atlantic Radio System|NARS]])
*[[BMEWS Central Computer and Display Facility]] (CC&DF){{r|NORAD1962B}} at Ent AFB ([[Zone of the Interior|ZI portion]] of BMEWS),<ref name=NORAD1958 /> with '''RCA Display Information Processor''' (DIP){{r|Gandy}}—DIPS displays were also at the [[Offutt AFB]] war room floor and balcony,<ref>{{cite AV media |title=SAC Command Post, Reel 2 |url=http://nsarchive.gwu.edu/nukevault/ebb304/film03.htm |publisher=  National Archives Motion Pictures Unit, Record Group 342 via nsarchive.gwu.edu |access-date=March 10, 2014}}</ref> as well as at [[Joint War Room|the Pentagon]]<ref name=DelPapa>{{cite report |last1=Del Papa |first1=Dr. E. Michael |last2=Warner |first2=Mary P |date=October 1987 |title=A Historical Chronology of the Electronic Systems Division 1947–1986 |url=http://apps.dtic.mil/dtic/tr/fulltext/u2/a201708.pdf |archive-url=https://web.archive.org/web/20131224105532/http://www.dtic.mil/dtic/tr/fulltext/u2/a201708.pdf |url-status=live |archive-date=December 24, 2013 |number=ESD-TR-88-276 (AD-A201 708) |access-date=March 8, 2014 |quote=7 November [1984] Installation of [SSPARS] radar hardware at Site I, Thule, Greenland, for the Ballistic Missile Early Warning System (BMEWS) was begun.}}</ref>
To predict when parts might break down,{{r|Ellensburg}} the contractor also installed [[RCA 501]] computers<ref>{{cite web|url=http://www.vintchip.com/mainframe/RCA501/RCA501.html |title=RCA501 |url-status=dead |archive-url=https://web.archive.org/web/20120702231735/http://www.vintchip.com/MAINFRAME/RCA501/RCA501.html |archive-date=July 2, 2012 }}</ref> with 32k high-speed memory, 5-76KC 556 bpi 3/4" tape drives, and 200-track random-access [[Low-frequency effects|LFE]] drums.{{Citation needed|reason=The previous uncited paragraph also had "Every wire was able to be traced from origin to destination with software and the weight of the cable interconnecting cabinets was automatically calculated by an RCA 501 machine language program named "signal path" written by [[Robert Goerss]], computing facility director."|date=March 2014}}  The initially replaced portions of BMEWS included [[Space Defense Center|the Ent CC&DF]] by the Burroughs 425L Missile Warning System at the [[Cheyenne Mountain Complex]]<ref name=GAO1978>{{cite web|date=September 21, 1978|title=NORAD's Information Processing Improvement Program: Will It Enhance Mission Capability?|url=http://www.gao.gov/assets/130/123974.pdf|format=Report to Congress|publisher=Comptroller General|access-date=January 24, 2013|quote=The 496L Spacetrack system uses a Philco 212 computer as its primary processor. … The off-line utility processors are two Philco 1000 computers which can also serve as backup processors for the 496L system and the Automatic Digital Relay Switch, if necessary. … The NCS segment will replace the [[Burroughs Corporation|Burroughs]] 425L Command and Control system including the Univac 1218s, the 425L Back-up system, the Command Center Processing system, and the Display Information Processor.}}</ref> ([[full operational capability|FOC]] 1 July 1966.)<ref name=DelPapa /> The original Missile Impact Predictors were replaced ([[Initial operational capability|IOC]] on 31 August 1984),<ref name=DelPapa /> and BMEWS systems were entirely replaced by 2001 (e.g., radars were replaced with AN/FPS-120 SSPARS) after [[Satellite Early Warning System]]s had been deployed (e.g., 1961 [[Missile Defense Alarm System|MIDAS]], 1968 [[Project 949]], and 1970 [[Defense Support Program|DSP]] satellites).

==Classification of radar systems==
{{further|Joint Electronics Type Designation System}}
Under the [[Joint Electronics Type Designation System]] (JETDS), all U.S. military radar and tracking systems are assigned a unique identifying alphanumeric designation. The letters “AN” (for Army-Navy) are placed ahead of a three-letter code.<ref name=EWRS2013>{{cite book|author=Avionics Department|title=Electronic Warfare and Radar Systems Engineering Handbook|edition=4|chapter=Missile and Electronic Equipment Designations|page=2-8.1|publisher=Naval Air Warfare Center Weapons Division|location=Point Mugu, California|year=2013|url=https://apps.dtic.mil/sti/tr/pdf/ADA617071.pdf}}</ref>
*The first letter of the three-letter code denotes the type of platform hosting the electronic device, where A=Aircraft, F=Fixed (land-based), S=Ship-mounted, and T=Ground transportable.
*The second letter indicates the type of equipment, where P=Radar (pulsed), Q=Sonar, and R=Radio.
*The third letter indicates the function or purpose of the device, where G=Fire control, R=Receiving, S=Search, and T=Transmitting.

Thus, the AN/FPS-49 represents the 49th design of an Army-Navy “Fixed, Radar, Search” electronic device.<ref name=EWRS2013/><ref name=Winkler1997>{{cite book|last=Winkler|first=David F.|title=Searching the Skies: The Legacy of the United States Cold War Defense Radar Program|chapter=Radar Systems Classification Methods|page=73|publisher=United States Air Force Headquarters Air Combat Command|location=Langley AFB, Virginia|year=1997|lccn=97020912|url=https://nuke.fas.org/guide/usa/airdef/1997-06-01955.pdf}}</ref>

== Early tests ==
[[File:1961 Eyes of the North - minute 4-51 -- BMEWS arcs and Q points.png|thumb|The Thule site J [[BMEWS]] station's detection arcs{{efn|The Thule site J [[BMEWS]] station's detection arcs of 200°<ref>{{Cite news |last=Hanley |first=Charles J |agency= [[Associated Press]] |date=17 August 1987 |title=Soviets, Eskimos protest Thule radar |url=https://news.google.com/newspapers?nid=1454&dat=19870817&id=X0lOAAAAIBAJ&pg=6837,867926 |format=Google news archive |newspaper=Morning Star |location= Wilmington, North Carolina |access-date=9 March 2014 |quote=The radar, a Phased Array Warning System…can "see" 3,200 miles, 200 miles farther than the old system, and has a 240-degree arc…40 degrees more than the old.}}</ref> were a missile warning "fence" created by 4 radars' separate arcs: each AN/FPS-50 created 2 arcs (shown) centered at 3.5° and 7° elevation<ref name=BMW /> (exaggerated in illustration.)  Each arc was created by a smaller radar beam ~1° wide x 3.5° high at a "horizontal sweep rate...fast enough that a missile or satellite cannot pass through...undetected".<ref name=BMW /> Concerns in 1962 of "ERBM's (Extended Range Ballistic Missiles)" were that missile speeds after burnout would be higher than the initially-deployed Soviet ICBMs{{r|NORAD1958B}} and prevent the sweeping "Lower Fan" and then the "Upper Fan" (with "revisit time of 2 sec"){{r|Skolnik}} from detecting the missiles.
A missile within the lower arc (~1.75-5.25° elevation) would be detected at a "Lower Fan Q Point" (black dot) and then by the upper fan (black dot with jagged outline), which allowed the impact area to be estimated from "where the object crossed the two fans and the elapsed time interval between fan crossings"<ref name=BMW /> (displays showed the uncertain impact point as an elliptical area.)   The free flight range of the missile outside the atmosphere (burnout to reentry) depends on the flight path angle and on the missile's parametric value of Q calculated from altitude and speed—additional ballistic range within the atmosphere to an estimated burst altitude was determined from computerized look-up tables in the Missile Impact Predictor.<ref name=BMW />}}]]

On 2 June 1955, a General Electric [[AN/FPS-17]] "XW-1" radar at Site IX<ref name=Zabetakis>{{Cite report |last1=Zabetakis |first1=Stanley G |last2=Peterson |first2=John F |date=July 2, 1996 |orig-year=Fall 1964 |title=The Diyarbakir Radar |url=https://www.cia.gov/library/center-for-the-study-of-intelligence/kent-csi/vol8no4/html/v08i4a05p_0001.htm |archive-url=https://web.archive.org/web/20080312094049/https://www.cia.gov/library/center-for-the-study-of-intelligence/kent-csi/vol8no4/html/v08i4a05p_0001.htm |url-status=dead |archive-date=March 12, 2008 |access-date=March 10, 2014 |quote=Data on target missiles or satellites are recorded in each radar channel by photographing a five-inch intensity-modulated oscilloscope with the camera shutter open on a 35-mm film moving approximately five inches per minute. ... The [[Foreign Technology Division|FTD]] Oscar equipment consists of a film reader which gives time and range data in analog form, a converter unit that changes them to digital form, and an IBM printing card punch that receives the digital data. The Oscar equipment and human operator thus generate a deck of IBM cards for...each target's position through time.}}</ref> [[Pirinçlik Air Base|in Turkey]] that had been expedited was completed by the US in proximity to the ballistic missile launch test site at [[Kapustin Yar]] in the [[Soviet Union]]<ref name=StoneBanner /> for tracking Soviet rockets<ref name=Skolnik>{{cite web |last=Skolnik |first=Merrill |title=Oral-History |url=http://www.ieeeghn.org/wiki/index.php/Oral-History:Merrill_Skolnik |format=audio transcript |publisher=IEEE Global History Network |access-date=March 10, 2014 }}</ref> and to demonstrate the feasibility of advanced [[Doppler effect|Doppler]] processing, high-power system components, and computerized tracking needed for {{sic|BMEWS<!--BMEWS hadn't been named in 1955-->}}.<ref name=StoneBanner />

The first missile tracked was on 15 June, and the radar's parabolic reflector was replaced in 1958,{{r|Zabetakis}} and its range was extended from 1000 to 2000 nautical miles<ref>{{cite AV media |year=1960 |title=Development of the Soviet Ballistic Missile Threat |url=http://www2.gwu.edu/~nsarchiv/nukevault/ebb304/film02.htm |format=George Washington University video |publisher=USAF Aerospace Audio Visual Service |access-date=March 9, 2014}}</ref> after the [[Gaither Report|1957 Gaither Commission]] identified that because of expected Soviet ICBM development, there would be little likelihood of [[Strategic Air Command|SAC's]] bombers surviving since there was no way to detect an incoming attack until the first warhead landed.<ref name=Freeman>{{cite news |last=Freeman |first=Maj Steve |date=September 1997|volume=5 |issue= 6|edition= Special Anniversary |title=Visionaries, Cold War, hard work built the foundations of Air Force Space Command |location=Peterson Air Force Base |newspaper=Guardian Magazine…funded Air Force newspaper |pages=6, 9 }}</ref>

BMEWS' General Operational Requirement 156 was issued on 7 November 1957 (BMEWS was designed to go with the active portion of [[Project Wizard|the WIZARD system]]) and on 4 February 1958; the USAF informed [[Air Defense Command]] (ADC) that BMEWS was an "all-out program" and the "system has been directed by [[Presidency of Dwight D. Eisenhower|the President]], has the same national priority as the ballistic missile and satellite programs and is being placed on the Department of Defense master urgency list".<ref>USAF memo to Air Defense Command cited in 1958 NORAD/CONAD Historical Summary, Jan-Jun</ref> By July 1958 after NORAD manning began, ADC's 1954 blockhouse for the Ent AFB command center had inadequate floor space; and Ent's "requirement for a ballistic missile defense system display facility...brought renewed action...for a new command post"<ref name=NORAD1958 /> (the JCS approved the nuclear bunker on 11 February 1959).

== Planning and development ==
[[File:BMEWS Tac Ops Room.jpg|thumb|BMEWS tracking monitors in the Thule Tactical Operations Room, which were upgraded in 1987{{r|AFHindex}}{{efn|(renamed "Missile Warning Operations Center"<ref>{{Cite web|url=https://www.globalsecurity.org/space/facility/clear-mwoc.htm|title=Clear AFS|website=www.globalsecurity.org|accessdate=25 June 2023}}</ref>)}}]]

On 14 January 1958, the US announced its decision to establish a Ballistic Missile Early Warning System<ref name=Chronology>{{cite web|title=NORAD Selected Chronology |url=https://fas.org/nuke/guide/usa/airdef/norad-chron.htm |publisher=Federation of American Scientists |access-date=March 5, 2014 |quote=14 Jan 58 -- United States announced decision to establish a Ballistic Missile Early Warning System }} (list also [http://www.norad.mil/about/NORAD%20History_ENGLISH.pdf at NORAD.mil] {{webarchive |url=https://web.archive.org/web/20120915120606/http://www.norad.mil/about/NORAD%20History_ENGLISH.pdf |date=September 15, 2012 }} & [https://books.google.com/books?id=KVzNqkRgSPsC&dq=spadats+bmews&pg=PA10 in 2008 book]</ref> with Thule to be operational in 1959—total Thule/Clear costs in a May 1958 estimate were ~$800 million (an October 13, 1958, plan for both estimated completion in September 1960.)<ref name=Wainstein>{{Cite report |last=Wainstein |title=Evolution of Command and Control… |url=http://apps.dtic.mil/dtic/tr/fulltext/u2/a331702.pdf |archive-url=https://web.archive.org/web/20140311182410/http://www.dtic.mil/dtic/tr/fulltext/u2/a331702.pdf |url-status=live |archive-date=March 11, 2014 |access-date=March 9, 2014|display-authors=etal}}</ref>  The [[Lincoln Laboratory]]'s radar at [[Millstone Hill]], Massachusetts, was built and provided data to a 1958<ref>{{cite book |url= http://dl.acm.org/citation.cfm?id=1458064 |date= December 3, 1958|pages= 91–94|doi= 10.1145/1458043.1458064|isbn= 9781450378666|s2cid= 17821721|chapter= The logical design of CG24|title= Papers and discussions presented at the December 3-5, 1958, eastern joint computer conference: Modern computers: Objectives, designs, applications on XX - AIEE-ACM-IRE '58 (Eastern)|last1= Dinneen|first1= G. P.|last2= Lebow|first2= I. L.|last3= Reed|first3= I. S.}}</ref> for trajectory estimates, e.g., [[Cape Canaveral]] missiles, and an adjunct high-power UHF test facility employed the Millstone transmitter to stress-test the components that were candidates for the operational BMEWS.<ref name=StoneBanner /> (A twin of the Millstone Hill radar was dedicated at [[Saskatchewan]]'s [[Prince Albert Radar Laboratory]] on June 6, 1959.)<ref name=StoneBanner /> A prototype AN/FPS-43 BMEWS radar<ref name=BMW /> completed at [[Trinidad]] in 1958 went operational on 4 February 1959, the date of an [[Atlas II|Atlas II B]] firing from [[Cape Canaveral]] [[Launch Complex 11]]<ref>{{Cite web|url=http://www.siloworld.net/MISSILE%20%20LAUNCHES/CAPE/Launches/atlas__b.htm|title=ATLAS B|accessdate=June 25, 2023}}</ref> (lunar reflection was tested January–June 1960).<ref>{{Cite web|url=http://www.dtic.mil/dtic/tr/fulltext/u2/265165.pdf|title=|archive-url=https://web.archive.org/web/20140311181855/http://www.dtic.mil/dtic/tr/fulltext/u2/265165.pdf |accessdate=June 25, 2023|archive-date=March 11, 2014 }}</ref> On June 30, 1958, NORAD emphasized that the BMEWS could not be considered as a self-contained entity separate from the [[LIM-49 Nike Zeus|Nike Zeus]], or vice versa.<ref>{{Cite report |date=June 30, 1958 |title=NORAD BMEWS and AICBM System Display}} (cited by 1958 NORAD/CONAD Historical Summary, Jan-Jun)</ref>

On 18 March 1959, the USAF told the BMEWS Project Office{{Where|The "DEW Line System Office" was at Ent AFB, but where was the "BMEWS Project Office" ([[Electronic Systems Division]]?)--and how does it differ from the SPO opened in late 1959? |date=May 2013}} to proceed with an interim facility<ref name=NORAD1959>{{Cite NORAD Historical Summary |version=1959 |pages=92, 94|accessdate=April 22, 2013}}</ref>{{rp|93}} for the "[[Space Defense Center|AICBM control center]]" with an [[anti-ballistic missile|anti-ICBM]] [[Command, control, and coordination system|C<sup>3</sup> computer]]<ref name=NORAD1958B>{{Cite NORAD Historical Summary |version=1958b |accessdate=April 30, 2013}}</ref>{{rp|148}} (e.g., for when the USAF [[Wizard Program|Wizard]]{{r|NORAD1958B}}{{rp|157}} and/or Army Nike Zeus{{r|Rogers}} ABMs became operational), and the basement of the 1954 ADC blockhouse was considered for the interim center.{{r|NORAD1958B}}{{rp|158}}  A "[[Space Detection and Tracking System|satellite prediction computer]]" could be added to the planned missile warning center if [[Cheyenne Mountain nuclear bunker|Cheyenne Mountain's "hardened COC]] slipped considerably beyond January 1962"<ref name=NORAD1959 />{{rp|93}} (tunneling began in June 1961.)   In early 1959 for use at Ent in September 1960,<!--{{rp|94}}--> a BMEWS display facility with "austere and economical construction with minimum equipment" was planned in an "annex to the current COC building".<ref name=NORAD1959 />  In late 1959, [[DARPA|ARPA]] opened{{Where|date=March 2014}} the 474L System Program Office,<ref name=GlobalSecurity>{{cite web |title=Ballistic Missile Early Warning System (BMEWS): AN/FPS-50 Detection Radar AN/FPS-92 Tracking Radar |url=http://www.globalsecurity.org/space/systems/bmews.htm |publisher=GlobalSecurity.org |access-date=March 5, 2014}}</ref> and BMEWS' "[[12th Missile Warning Squadron]] at Thule...began operating in January 1960."<ref>{{Cite book |last=Muolo |format=manual |date=December 1993 |title=Space Handbook |url=http://www.au.af.mil/au/awc/awcgate/au-18/au180001.htm |archive-url=https://archive.today/20121212022106/http://www.au.af.mil/au/awc/awcgate/au-18/au180001.htm |url-status=dead |archive-date=December 12, 2012 |publisher=Air University Press }}</ref>  Following a<!--n August 1959--> [[Nike Zeus|Nike ABM]] intercept of a test missile, the planned Cheyenne Mountain mission was expanded in August 1960 to "a hardened center from which [[CINCNORAD]] would supervise and direct operations against space attack as well as air attack"<ref name=ARDC>{{cite report|title=title [[To be determined|tbd]]|publisher=[[Air Research and Development Command]]}} (cited by Schaffel, p. 262)</ref> (NORAD assumed "operational control of all space assets with the formation of" SPADATS in October 1960.){{r|Freeman}}  The [[1st Aerospace Surveillance and Control Squadron]] (1st Aero) was activated at Ent AFB on 14 February 1961; and [[Federal Building (Ent AFB)|Ent's Federal Building]] was completed {{circa|lk=no|1960-1}}.

== Deployment ==
[[File:Thule BMEWS.jpg|thumb|4 AN/FPS-50 detection reflectors at [[Thule Site J]].{{efn|replaced by an AN/FPS-120 with "two-faced...phased array radar...in 2QFY87."<ref>{{cite web |title= Ballistic Missile Early Warning System (BMEWS) at Clear |url= https://fas.org/spp/military/program/nssrm/initiatives/clearu.htm |archive-url= https://web.archive.org/web/20001217182500/http://fas.org/spp/military/program/nssrm/initiatives/clearu.htm |archive-date= December 17, 2000 |date= July 12, 1999}}</ref>}} The concrete foundation included a large refrigeration system to prevent the curing concrete's heat from melting the [[permafrost]]]]

Clear AFS construction began in August 1958{{r|Ellensburg}} with 700 workers{{r|Ellensburg}} and was completed 1 July 1961,<ref name=Ellensburg>{{Cite news |date=June 18, 1961 |title=Watchful eye of BMEWS turns toward Soviets |url=https://news.google.com/newspapers?nid=860&dat=19610619&id=PG5OAAAAIBAJ&pg=6197,6117601 |format=Google news archive |newspaper=Ellensburg Daily Record |access-date=March 9, 2014 }}</ref> and [[Thule Site J]] construction began by 18 May 1960,<ref>{{Cite news |date=May 18, 1960 |title=Big Rocket Detector Is Set for Operation |url=https://news.google.com/newspapers?nid=1906&dat=19600518&id=qckfAAAAIBAJ&pg=1035,684283 |format=Google news archive |newspaper=The Fort Scott Tribune |access-date=March 9, 2014 }}</ref> with radar pedestals complete by 2 June.<ref name=Rogers>{{Cite news |last=Rogers |first=Warren Jr. |date=June 2, 1960 |title=Summit Failure Speeds Up Development of BMEWS |url=https://news.google.com/newspapers?nid=1817&dat=19600602&id=N_QhAAAAIBAJ&pg=7199,137041 |publisher=Herald Tribune News Service |access-date=March 9, 2014 }}</ref> Thule testing began on 16 May 1960,<ref>{{cite news |url= https://news.google.com/newspapers?nid=1314&dat=19600516&id=kTRWAAAAIBAJ&pg=5560,227676 |title= Electronic Sky Watch is Nearing |agency= AP |location= Spokane, Washington |page= 1 |newspaper= The Spokesman-Review |date= May 16, 1960}}</ref> IOC was completed on 30 September,<ref name=Wainstein /> and the initial operational radar transmission was in October 1960{{r|Newburgh}} (initially duplex vacuum tube [[IBM 709]]s occupied two floors).{{citation needed|date=November 2016|reason=Previous source was a recreational TV usenet newsgroup posting}}

On 5 October 1960, when Khrushchev was in New York,{{r|Pearson}} radar returns during moonrise at Thule<ref>{{cite web 
 |last=Sampson 
 |first=Curt 
 |date=January 25, 2010 
 |title=The Moon as a Soviet Missile Attack 
 |url=http://taihendaro.cynic.net/2010/01/moon-as-soviet-missle-attack.html 
 |archive-url=https://web.archive.org/web/20220119163818/http://taihendaro.cynic.net/2010/01/moon-as-soviet-missle-attack.html
 |archive-date=January 19, 2022
 |url-status=dead 
 |access-date=March 5, 2014}}</ref>
produced a [[false alarm]]. On 20 January 1961, [[CINCNORAD]] approved two-second FPS-50 frequency hoping to eliminate reception of echoes beyond artificial satellite orbits.<ref name=StoneBanner /> On 24 November 1961, an [[AT&T]] operator failure at their [[Black Forest, Colorado|Black Forest]] microwave station northeast of [[Colorado Springs]]<ref>{{Cite news |series=EVER WONDER? |title=AT&T caused NORAD blackout |url=http://gazette.com/article/123954 |archive-url=https://web.archive.org/web/20131224105544/http://gazette.com/article/123954 |url-status=dead |archive-date=24 December 2013 |publisher=[[Colorado Springs Gazette]] |date=August 26, 2011 |access-date=March 10, 2014 |quote=an engineer we'll call "Q" didn't follow instructions "for routining a TD2 transmitter and receiver." He enclosed diagrams showing what went wrong. There was no "500A termination on the Channel Dropping Network when he was running the Radio Frequency (RF) Sweep Generator to adjust the equipment." That generator leaked RF into the Channel Separating Filter "interfering with all the other transmitters in the Black Forest Microwave Station, causing a complete failure of all channels going to Ent. SAC scrambled all aircraft. Later SAC billed AT&T for all the fuel used." }}</ref>{{unreliable source?|date=November 2016|reason=Quotation is a non-fact checked reader reply to a news story.}} caused a BMEWS communications outage to Ent and Offutt{{snd}}a B-52 near Thule confirmed the site still remained.<ref>{{cite web |last=Philips |first=Alan F. |title=20 Mishaps That Might Have Started Accidental Nuclear War |url=http://www.nuclearfiles.org/menu/key-issues/nuclear-weapons/issues/accidents/20-mishaps-maybe-caused-nuclear-war.htm |publisher=NuclearFiles.org |access-date=March 5, 2014 |archive-date=May 10, 2020 |archive-url=https://web.archive.org/web/20200510120308/http://nuclearfiles.org/menu/key-issues/nuclear-weapons/issues/accidents/20-mishaps-maybe-caused-nuclear-war.htm |url-status=dead }}</ref>

Training for civilian technicians included a February 1961 RCA class in [[Riverton, New Jersey|New Jersey]] for a Tracking Radar Automatic Monitoring class.<ref>{{cite web |last=McManus |first=Gene |date=September 1996 |title=BMEWS – 51- Full Days |url=http://www.bwcinet.com/thule/1intro.htm |access-date=March 5, 2014 |archive-date=January 14, 2009 |archive-url=https://web.archive.org/web/20090114115952/http://www.bwcinet.com/thule/1intro.htm |url-status=dead }}</ref> The "Clear Msl Early Warning Stn, [[Nenana, Alaska|Nenana, AK]]" was assigned to [[Hanscom Field]], Massachusetts, by the JCA on 1 April 1961.<ref name=Mueller>{{Cite report |last=Mueller |first=Robert |year=1989 |title=Air Force Bases |url=https://media.defense.gov/2010/Sep/21/2001330255/-1/-1/0/AFD-100921-026.pdf |volume=I: Active Air Force Bases Within the United States of America on 17 September 1982 |publisher=Office of Air Force History |isbn=0-912799-53-6 }}</ref> By 16 May 1961, Ent's "War Room at NORAD" had a glass map for plotting aircraft and had a "map [that] lights up" to show multiple impact ellipses and times "before the huge missile[s] would burst"<ref name=Pearson>{{Cite news |last=Pearson |first=Drew |date=May 16, 1961 |title=A Day In The War Room At NORAD |url=https://news.google.com/newspapers?nid=1964&dat=19610516&id=0fIiAAAAIBAJ&pg=3024,2959829 |format=Google news archive |newspaper=The Palm Beach Post |access-date=March 9, 2014 }}{{Dead link|date=December 2024 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> (separate from Ent's BMEWS CC&DF building, the two-story blockhouse had a war room with, left of the main NORAD region display, a BMEWS display map and "threat summary display" with a count of incoming missiles.)<ref>{{Cite news |date=November 26, 1964 |title=NORAD Center Located At Colorado Springs Site |url=https://news.google.com/newspapers?id=_ERlAAAAIBAJ&pg=4226%2C3522073 |format=Google news archive |newspaper=The Othello Outlook |page=3 |access-date=March 9, 2014 |quote=COMMAND POST – The main battle staff position in the Combat Operations Center (COC)...fronts a display area which allows observers to see the positions of airborne objects thousands of miles away.}}</ref>{{efn|The p. 4 command post photo caption does not identify if it is in the Ent blockhouse (1954–1963) or in the [[Chidlaw Building]], where war room operations moved to the NORAD/CONAD Combined Operations Center in 1963.}} The Trinidad Test Site transferred from [[Griffiss Air Force Base|Rome AFB]] to [[Patrick AFB]] on 1 July 1961 (closed as "Trinidad Air Station" on 1 October 1971){{r|Mueller}} and the same month, the 1st Aero began using Ent's [[Space Detection and Tracking System]] (SPADATS) operation center in building P4's annex<ref>{{Full citation needed|reason=The actual document needs identified for this fact instead of a set of reports.|date=November 2013}}1961–1969 Historical reports from the Squadron on file at the Air Force Historical Research Agency, Maxwell AFB AL, AFHRA Microfilm reel KO363</ref> (Cheyenne Mtn's [[Space Defense Center]] became fully operational in 1967.)<ref name=Chronology /> The BRCS undersea cable was cut "presumably by fishing trawlers" in September, October, and November 1961 (the BMEWS teletype and backup [[Single Side Band|SSB]] substituted);{{r|NORAD1962B}} and in December 1961, Capt. Joseph P. Kaufman was charged "with giving [BMEWS] defense data to ... East German Communists."<ref>{{cite news |url= https://news.google.com/newspapers?nid=336&dat=19611222&id=NWUvAAAAIBAJ&pg=6861,5107035 |title= Captain Faces Secrets Count |agency= HTNS |newspaper= The Deseret News |date= December 22, 1961 |page= A3 }}</ref>

=== BMEWS surveillance wing ===
The [[71st Flying Training Wing|71st Surveillance Wing, Ballistic Missile Early Warning System]], was activated on 6 December 1961, at [[Ent AFB]] (renamed [[71st Missile Warning Wing]] on 1 January 1967, at [[McGuire AFB]] 21 July 1969 – 30 April 1971).{{r|Mueller}}  Syracuse's BMEWS Test Facility at GE's High-Power Radar Laboratory<ref>{{Cite journal |doi = 10.1109/EE.1960.6432626|title = Of current interest: Surveillance radar subsystem for Air Force's BMEWS, Site 1|journal = Electrical Engineering|volume = 79|issue = 5|pages = 430–431|year = 1960}}</ref> became the responsibility of [[Rome Air Development Center]] on 11 April 1962<ref name=Strain>{{Cite report |title=Forty Years of Research and Development at Griffis Air Force Base: June 1951-June 1991 |url=https://apps.dtic.mil/sti/pdfs/ADA250435.pdf |archive-url=https://web.archive.org/web/20130408131948/http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA250435 |url-status=live |archive-date=April 8, 2013 |number=AD-A250 435 |publisher=Rome Laboratory |access-date=March 10, 2014 }}</ref> (Syracuse's Eagle Hill Test Annex closed in 1970){{r|Mueller}} and on 31 July 1962, NORAD recommended a tracking radar station at Cape Clear to close the BMEWS gap with Thule for low-angle missiles (versus those with the 15- to 65-degree angle for which BMEWS was designed.)<ref name=NORAD1962B>{{Cite web|url=http://www.northcom.mil/Portals/28/Documents/Supporting%20documents/(U)%201962%20NORAD%20CONAD%20History%20Jul-Dec.pdf|title=1962 NORAD/CONAD Historical Summary, July-December|accessdate=June 25, 2023}}</ref> By mid-1962, BMEWS "quick fixes" for [[Electronic counter-countermeasures|ECCM]] had been installed at Fylingdales Moor, Thule and Cape Clear AK{{r|NORAD1962B}} and by June 30, integration of BMEWS and SPADATS at Ent AFB was completed.<ref name=DelPapa /> During the [[Cuban Missile Crisis]], the [[USS Rancocas|Moorestown AN/FPS-49 radar]] on 24 October was "withdrawn from SPADATS and realigned to provide missile surveillance over Cuba."{{r|NORAD1962B}} 1962 "strikes and walkouts" delayed Fylingdales' planned completion from March until September 1963 and on 7 November, the Pentagon BMEWS display subsytem installation was complete.<ref name=DelPapa />  At the end of 1962, NORAD was "concerned over BMEWS' virtual inability to detect objects beyond a range of 1500 nautical miles."{{r|NORAD1962B}} The Moorestown FPS-49 completed a BMEWS "signature analysis program" on scale models by January 1963.<ref name=Det3>{{Cite report |date=January 10, 1963 |title=Scale Model Radar Cross Section Data |url=http://www.dtic.mil/dtic/tr/fulltext/u2/460987.pdf |archive-url=https://web.archive.org/web/20140311181204/http://www.dtic.mil/dtic/tr/fulltext/u2/460987.pdf |url-status=dead |archive-date=March 11, 2014 |publisher=Detachment 3, [[9th Aerospace Defense Division|9th...Division]] |location=BLDG 116-20, RCA, Moorestown NJ |access-date=March 9, 2014 |quote=eventual transfer to a [[Space Defense Center|Spacetrack Analysis Center]] at Colorado Springs.}}</ref>

== Air Defense Command / Aerospace Defense Command ==
[[File:RAF Fylingdales golfballs 1989.jpg|thumb|Fylingdales AN/FPS-49 radomes in 1986{{efn|2 of 3 radars were "constantly swinging back and forth in preset arcs to the east and north, looking 4,800 kilometres into space, from just above the horizon to nearly straight overhead".<ref name=Sydney>{{cite news |url= https://news.google.com/newspapers?nid=1301&dat=19880615&id=q3NWAAAAIBAJ&pg=5477,3917703 |title= Soviets scan British radar improvements |page= 18 |newspaper= The Sydney Morning Herald |date= June 15, 1988}}</ref> Fylingdales radars were replaced by Raytheon/[[Cossor AeroSpace]] and [[Control Data Corporation]], at a cost of US $100M (3-faced phased array antenna and embedded CDC-Cyber computer){{Citation needed|date=March 2014}} and later changed to an [[Upgraded Early Warning Radar]] by [[Boeing Integrated Defense Systems]]<ref>{{cite web|title=Fylingdales |url=http://www.raytheon.co.uk/ourcompany/facilities/fylingdales/index.html |publisher=Raytheon.co.uk |access-date=March 8, 2014 |url-status=dead |archive-url=https://web.archive.org/web/20140311182300/http://www.raytheon.co.uk/ourcompany/facilities/fylingdales/index.html |archive-date=March 11, 2014 }}</ref> with 3 faces built August 1989-October 1992.<ref name=UK>{{Cite book |last=Stocker |first=Jeremy |editor=Gray, Colin S. |editor2=Murray, Williamson |year=2004 |isbn=0-203-30963-4 |publisher=Frank Cass |title=Britain and Ballistic Missile Defence 1942–2002 |url=http://sobchak.files.wordpress.com/2009/02/britain-and-ballistic-missile-1942-2002.pdf |issn=1473-6403 |access-date=March 9, 2014 |quote=in March 1963 an Air Ministry review of ABM systems said of MIDAS that ‘performance to date has been disappointing’.<sup>78</sup> … A teletype circuit was established between NORAD and the ADOC in Britain to pass information derived from Site 1 at Thule.<sup>95</sup> This was supplemented by a voice circuit with agreed formatted messages, and both were operational by October 1960. … AN/FPS-49 Range resolution 240 nm Maximum range 2,650 nm Minimum target at 1,650&nbsp;m 2.8 m<sup>2</sup> Impact accuracy North America 135 nm}}</ref> }}]]

Operations transferred from civilian contractors (RCA Government Services){{r|Spring1963}}{{rp|29}} to ADC on 5 January 1962<ref name=Newburgh>{{Cite news |date=June 19, 1964 |title=Ballistic Warning Is Aim of BMEWS |url=https://news.google.com/newspapers?nid=1982&dat=19640619&id=4uVGAAAAIBAJ&pg=744,2767457 |format=Google news archive |location=[[Newburgh, New York]] |newspaper=The Evening News |access-date=March 9, 2014 |quote=high-speed scanning switches and a massive array of feedhorns… [[Federal Signal Corporation|Federal Electric Corp.]], Paramus, N.J., is the prime contractor for manning and maintaining the Thule BMEWS site.}}</ref> (renamed [[Aerospace Defense Command]] in 1968.)  Fylingdales became operational on 17 September 1963,<ref>{{cite news |url= https://news.google.com/newspapers?nid=1051&dat=19641126&id=_ERlAAAAIBAJ&pg=4317,3542112 |title= Early Warning System has Important Role in NORAD |newspaper= The Othello Outlook |location= Othello, Washington |date= November 26, 1964 |page= 6 }}</ref>{{r|Newburgh}} and Site III transferred to [[RAF Fighter Command]] on 15 January 1964.<ref>
{{cite book
 |last=Wilson
 |first=B.C.F.
 |date=January 1, 1983 
 |title=A History - Royal Air Force Fylingdales
 |publisher= Royal Air Force Fylingdales (January 1, 1983)
 |isbn=0950852104
 |quote=[plaque in the Tactical Operations Room] This plaque commemorates the commissioning of Royal Air Force Fylingdales as Site III of the Ballistic Missile Early Warning System on 17 September 1963. This site is a joint enterprise of the United States of America and Great Britain for the protection of both the North American Continent and the United Kingdom.}}
</ref>
Remaining BMEWS development responsibilities transferred to the "Space Track SPO (496L)" when the BMEWS SPO closed on 14 February 1964<ref name=DelPapa />—e.g., the AN/FPS-92 with "66-inch panels"<ref>{{cite book |url=https://news.google.com/newspapers?nid=1955&dat=19620329&id=VJAuAAAAIBAJ&pg=2794,715597 |title= Radome is maze of wires, girders |newspaper= Reading Eagle |date= March 29, 1962 |page= 17 }}</ref> was added to Clear in 1966<ref>{{cite news |url= https://news.google.com/newspapers?nid=2512&dat=19660708&id=ZadIAAAAIBAJ&pg=1025,753004 |title= Electronic Eye Scans Eurasian Air Space |agency= AP |newspaper= The Morning Record |date= July 8, 1966 |page= 14 }}</ref> (last of the five tracking radars),<ref>{{Cite news |date=July 8, 1966 |title=Electronic Eye Watches For Sneak Missile Attack |url= https://news.google.com/newspapers?nid=1876&dat=19660708&id=J4MsAAAAIBAJ&pg=5982,1160625 |format=Google news archive |newspaper=Herald-Journal |access-date=March 9, 2014 |quote=rotating 84-foot parabolic radar dish antenna…weighing 185 tons, can detect and track a 16-inch piece of wire 1-32nd of an inch in diameter, at a distance of 2,500 miles… The electronic dishes, each costing $19 million…}}</ref> and in 1967, BMEWS modification testing was complete on 15 May, when the system cost totaled $1.259 billion,<ref name=DelPapa /> equivalent to ${{Format price|{{Inflation|US-GDP|1259000000|1967}}}} in {{Inflation/year|US-GDP}}.{{Inflation/fn|US-GDP}} 
In 1968, Ent's 9th Division HQ had a Spacetrack/BMEWS Maintenance Section.<ref>{{cite web |url= https://higherlogicdownload.s3.amazonaws.com/AFA/63e0124a-9fef-4973-95ab-b18225a8c855/UploadedImages/Officers%20and%20Directors/OAY_Program/OAY_History.pdf |title= Outstanding Airman of the Year History |publisher= Unknown source via higherlogicdownload.s3.amazonaws.com |access-date= November 5, 2016 |archive-url= https://web.archive.org/web/20161106063221/https://higherlogicdownload.s3.amazonaws.com/AFA/63e0124a-9fef-4973-95ab-b18225a8c855/UploadedImages/Officers%20and%20Directors/OAY_Program/OAY_History.pdf |archive-date= November 6, 2016 |url-status= dead }}{{unreliable source?|date=November 2016|reason=No clear author or verifiable source}}{{synthesis inline|date=November 2016|reason=Original research / Synthesis based on questionable source.}}</ref>

In 1975, [[SECDEF]] told Congress that Clear would be closed when [[Cobra Dane]] and the [[Beale AFB]] [[PAVE PAWS]] became operational.<ref>{{cite report |archive-url= https://web.archive.org/web/20111127001505/http://www.dod.mil/pubs/foi/logistics_material_readiness/acq_bud_fin/244.pdf |archive-date= November 27, 2011 |url= http://www.dod.mil/pubs/foi/logistics_material_readiness/acq_bud_fin/244.pdf |title= Report of the Secretary of Defense to the Congress on the FY 1976 and Transition Budgets... |first= James R. |last= Schlesinger |date= February 5, 1975}}</ref> By 1976, BMEWS included [[IBM 7094]], [[CDC 6000]], and [[Honeywell 800]] computers.<ref>{{Cite news|format=job advertisement |title=Electronic Technicians BMEWS |url=http://209.212.22.88/DATA/RBR/1970-1979/1975/1975.08.20.pdf |page=27 |access-date=March 6, 2014 |quote=FELEC Services…a subsidiary of Federal Electric…newly awarded contract at Thule…IBM 360-7090 and 7094; CDC 6000; Honeywell 800 |url-status=dead |archive-url=https://web.archive.org/web/20140311193031/http://209.212.22.88/DATA/RBR/1970-1979/1975/1975.08.20.pdf |archive-date=March 11, 2014 }}</ref>

== USAF Space Command ==
On 1 October 1979, Thule and Clear transferred to [[Strategic Air Command]] when ADCOM was broken up<ref name=Johnson>compiled by {{Cite book |last1=Johnson |first1=Mildred W |date=December 31, 1980 |orig-year=Feb 1973 original by Cornett, Lloyd H. Jr |title=A Handbook of Aerospace Defense Organization 1946–1980 |url=http://www.usafpatches.com/pubs/handbookofadcorg.pdf |publisher=Office of History, [[Aerospace Defense Center]] |location=Peterson AFB |access-date=March 26, 2012 |archive-date=November 23, 2006 |archive-url=https://web.archive.org/web/20061123115752/http://www.usafpatches.com/pubs/handbookofadcorg.pdf |url-status=dead }}</ref><!--{{rp|46}}--> then to [[Air Force Space Command#History|Space Command]] in 1982. By 1981 Cheyenne Mountain had been averaging 6,700 messages per hour<ref>{{Cite report|title=Failures of the North American Aerospace Defense Command's (NORAD) attack warning system|url=https://books.google.com/books?id=Lo5Chva3cVgC&q=mountain|format=minutes of "hearings before a subcommittee of the Committee on Government Operations, House of Representatives, [[97th United States Congress|Ninety-seventh Congress]]; May 19 and 20, 1981"|publisher=United States Government Printing Office|access-date=January 23, 2013|quote=at Norad is the establishment of a Systems Integration Office}}</ref> compiled via sensor inputs from BMEWS, the [[Joint Surveillance System|JSS]], the 416N [[Submarine-launched ballistic missile|SLBM]] "Detection and Warning System, [[COBRA DANE]], and [[PARCS (radar)|PARCS]] as well as [[Satellite Early Warning System|SEWS]] and [[PAVE PAWS]]" for transmission to the [[National Command Authority (United States)|NCA]]<!-- ([[The Pentagon|Pentagon]]'s [[National Military Command Center|NMCC]], [[Raven Rock Mountain Complex|Raven Rock's]] [[ANMCC]], and SAC's [[Offutt Air Force Base|Offutt]]/[[The Notch|Notch]] bunkers)-->.<ref name=WWMCCS>{{cite report|date=January 19, 1981|title=Modernization of the WWMCCS Information System (WIS)|url=http://apps.dtic.mil/dtic/tr/fulltext/u2/a095409.pdf|archive-url=https://web.archive.org/web/20131224101313/http://www.dtic.mil/dtic/tr/fulltext/u2/a095409.pdf|url-status=live|archive-date=December 24, 2013|format=ADA095409|publisher=[[United States House Committee on Armed Services]]|access-date=August 29, 2012}}</ref>  To replace AN/FSQ-28 predictors, a late 1970s plan for processing returns from [[MIRV]]s<ref>{{cite book |url= https://books.google.com/books?id=x__CgnLTLqkC&q=%22Missile+Impact+Predictor%22+bmews&pg=PA197 |title= First Strike!: The Pentagon's Strategy for Nuclear War |first= Robert C. |last= Aldridge |page= 197|isbn= 9780896081543 |year= 1983 |publisher= South End Press }}</ref> installed in new Missile Impact Predictor computers was complete by September 1984.<ref name=DelPapa /><ref name=AFHindex>{{cite web | website=Air Force History Index|title=Document Detail for IRISNUM= 01073102
 | url=http://airforcehistoryindex.org/data/001/073/102.xml | access-date=25 June 2023}}</ref>

==Replacement==
The BMEWS was replaced by the [[Solid State Phased Array Radar System]] in 2001.<ref name="Chapman" />

== See also ==
{{Portal|Electronics}}
* [[Main Centre for Missile Attack Warning]] ([[Russia]])
* [[Solid State Phased Array Radar System]]
*[[List of radars]]
*[[List of military electronics of the United States]]

== Notes ==
{{notelist}}

== References ==
{{reflist|30em}}

== External links ==
* [https://www.youtube.com/watch?v=i-qYyIAeqXs US Air Force film]
* [https://web.archive.org/web/20120505055809/http://www.ll.mit.edu/publications/journal/pdf/vol12_no2/12_2widgetswonders.pdf Both Trinidad test radars & 1957 FPS-50 reflector scale model]
* [https://news.google.com/newspapers?nid=1499&dat=19610104&id=iuEpAAAAIBAJ&sjid=8yUEAAAAIBAJ&pg=4813,1400514 1961 Thule sketch, FPS-50 wave guides, & "memory and logic unit"] {{Webarchive|url=https://web.archive.org/web/20160312112552/https://news.google.com/newspapers?nid=1499&dat=19610104&id=iuEpAAAAIBAJ&sjid=8yUEAAAAIBAJ&pg=4813,1400514 |date=March 12, 2016 }}
* [http://www.c-and-e-museum.org/Pinetreeline/misc/other/misc3i.html 1961 BMEWS Rearward communications "billboard type" antenna]
* [https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/249994/Sanctuary_mag__number_42_2013.pdf construction of a Fylingdale's radome]
* [http://jsf1.homestead.com/MoorestownGolfBall.html "Moorestown's Giant Golf Ball]
* [http://www.real-whitby.co.uk/wp-content/gallery/raf-fylingdales-newsletter/scan.jpg ''Scan'' newsletter of Site III]
* [http://www2.gwu.edu/~nsarchiv/nukevault/ebb304/film03.htm SAC DIP screen with impact ellipses (Reel 2, minute 4:40)]
* [https://www.youtube.com/watch?v=WpWW6KzCu70 Eyes of the North]
* [http://www.criticalpast.com/video/65675061914_Ballistic-Missile-Early-Warning-System_technicians-working_watching-oscilloscopes_turning-knobs Flyingdales Rearward Data Room]

{{United States Missile Defense}}
{{AN/FPS}}<!---multiple radar equipment--->
{{USAF system codes}}

[[Category:Air defence radar networks]]
[[Category:1959 in military history]]
[[Category:Early warning systems]]
[[Category:Computer systems of the United States Air Force]]
[[Category:Military equipment introduced in the 1960s]]
[[Category:Military electronics of the United States]]