View source for Semi-Automatic Ground Environment

{{Short description|Historic US military computer network}}
{{About|the NORAD Cold War computer network|the radar installations in each sector|SAGE radar stations}}
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| image_caption       = The 4-story SAGE blockhouses with {{Convert|3.5|acre|ha|abbr=on}} of floor space<ref>[http://www.coldwarpeacemuseum.org/blockhouse.html The SAGE Blockhouse - Future Home of the Cold War / Peace Museum] {{webarchive|url=https://web.archive.org/web/20130511015842/http://www.coldwarpeacemuseum.org/blockhouse.html |date=2013-05-11 }}. Coldwarpeacemuseum.org. Retrieved on 2013-09-18.</ref> "were hardened [for] overpressures of" {{Convert|5|psi|abbr=on}}.{{r|Schaffel}}{{rp|264}}  A shorter adjoining building (left) had generators below the 4 intake/exhaust structures on the roof.{{r|EdwardsBenj}} (DC-01 shown) 
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| opened_date         = 1958 June 26 — DC-01<br>1958 December 1 — DC-03<br>1959 (early) — CC-01<br>1966 April 1 — CC-05
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| architect           = USAF [[Air Materiel Command]]<br>[[Western Electric]]<ref name=IYD/><br>[[System Development Corporation]]<ref name=IYD/><br>[[Burroughs Corporation]]
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The '''Semi-Automatic Ground Environment''' ('''SAGE''') was a system of [[mainframe computer|large computers]] and associated [[computer network|networking]] equipment that coordinated data from many [[radar]] sites and processed it to produce a single unified image of the airspace over a wide area.<ref>{{cite book |title=A Dictionary of Aviation |first=David W. |last=Wragg |isbn=9780850451634 |edition=first |publisher=Osprey |year=1973 |page=232}}</ref> SAGE directed and controlled the [[NORAD]] response to a possible Soviet air attack, operating in this role from the late 1950s into the 1980s. Its enormous computers and huge displays remain a part of [[Cold War]] lore, and after decommissioning were common props in movies such as ''[[Dr. Strangelove]]'' and [[Colossus: The Forbin Project|''Colossus'']], and on science fiction TV series such as ''[[The Time Tunnel]]''.

The processing power behind SAGE was supplied by the largest discrete component-based computer ever built, the [[IBM]]-manufactured [[AN/FSQ-7 Combat Direction Central|AN/FSQ-7]]. Each SAGE Direction Center (DC) housed an FSQ-7 which occupied an entire floor, approximately {{convert|22000|sqft|m2}} not including supporting equipment. The FSQ-7 was actually two computers, "A" side and "B" side. Computer processing was switched from "A" side to "B" side on a regular basis, allowing maintenance on the unused side. Information was fed to the DCs from a network of radar stations as well as readiness information from various defense sites. The computers, based on the raw radar data, developed "tracks" for the reported targets, and automatically calculated which defenses were within range. Operators used [[light gun (SAGE)|light gun]]s to select targets on-screen for further information, select one of the available defenses, and issue commands to attack. These commands would then be automatically sent to the defense site via [[teleprinter]].

Connecting the various sites was an enormous network of telephones, [[modem]]s and teleprinters. Later additions to the system allowed SAGE's tracking data to be sent directly to [[CIM-10 Bomarc]] missiles and some of the [[US Air Force]]'s [[interceptor aircraft]] in-flight, directly updating their [[autopilot]]s to maintain an intercept course without operator intervention. Each DC also forwarded data to a Combat Center (CC) for "supervision of the several sectors within the division"<ref name=Intro/> ("each combat center [had] the capability to coordinate defense for the whole nation").<ref name=Winkler/>{{Rp|<!--pdf -->51}}

SAGE became operational in the late 1950s and early 1960s at a combined cost of billions of dollars. It was noted that the deployment cost more than the [[Manhattan Project]]—which it was, in a way, defending against. Throughout its development, there were continual concerns about its real ability to deal with large attacks, and the [[Operation Sky Shield]] tests showed that only about one-fourth of enemy bombers would have been intercepted.<ref name=Mola2002>{{cite news |last=Mola |first=Roger A. |url=http://www.airspacemag.com/history-of-flight/this-is-only-a-test-3119878/ |title=This Is Only a Test |work=Air & Space Magazine |date=March 2002 |access-date=26 July 2017}}</ref> Nevertheless, SAGE was the backbone of [[North American Aerospace Defense Command|NORAD]]'s air defense system into the 1980s, by which time the [[Vacuum-tube computer|tube-based]] FSQ-7s were increasingly costly to maintain and completely outdated. Today the same command and control task is carried out by [[microcomputers]], based on the same basic underlying data.

==Background==

===Earlier systems===
{{Unreferenced section|date=September 2021}}

Just prior to [[World War II]], [[Royal Air Force]] (RAF) tests with the new [[Chain Home]] (CH) radars had demonstrated that relaying information to the [[fighter aircraft]] directly from the radar sites was not feasible. The radars determined the map coordinates of the enemy, but could generally not see the fighters at the same time. This meant the fighters had to be able to determine where to fly to perform an interception but were often unaware of their own exact location and unable to calculate an interception while also flying their aircraft.

[[File:Seattle-ADS-map.png|thumb|SAGE radar stations were grouped by Air Defense Sectors (Air Divisions after 1966).  The SAGE System networked the radar stations in over 20 of the sectors using AN/FSQ-7 centrals in Direction Center.]]

The solution was to send all of the radar information to a central control station where operators collated the reports into single ''tracks'', and then reported these tracks to the airbases, or ''sectors''. The sectors used additional systems to track their own aircraft, plotting both on a single large map. Operators viewing the map could then see what direction their fighters would have to fly to approach their targets and relay that simply by telling them to fly along a certain heading or ''vector''. This [[Dowding system]] was the first [[ground-controlled interception]] (GCI) system of large scale, covering the entirety of the UK. It proved enormously successful during the [[Battle of Britain]], and is credited as being a key part of the RAF's success.

The system was slow, often providing information that was up to five minutes out of date. Against propeller driven bombers flying at perhaps {{convert|225|mph}} this was not a serious concern, but it was clear the system would be of little use against jet-powered bombers flying at perhaps {{convert|600|mph}}. The system was extremely expensive in manpower terms, requiring hundreds of telephone operators, plotters and trackers in addition to the radar operators. This was a serious drain on manpower, making it difficult to expand the network.

The idea of using a computer to handle the task of taking reports and developing tracks had been explored beginning late in the war. By 1944, [[analog computer]]s had been installed at the CH stations to automatically convert radar readings into map locations, eliminating two people. Meanwhile, the [[Royal Navy]] began experimenting with the [[Comprehensive Display System]] (CDS), another analog computer that took X and Y locations from a map and automatically generated tracks from repeated inputs. Similar systems began development with the [[Royal Canadian Navy]], [[DATAR]], and the [[US Navy]], the [[Naval Tactical Data System]]. A similar system was also specified for the [[MIM-3 Nike Ajax|Nike]] SAM project, specifically referring to a US version of CDS,<ref>{{Cite journal |type=letter |last=Nelson |first=Maj Gen Morris R. |date=June 12, 1950 |title=subj: Employment of an American Version of CDS |location=USAFHRC microfilm }} (cited by Schaffel pdf p. 311)</ref> coordinating the defense over a battle area so that multiple batteries did not fire on a single target. All of these systems were relatively small in geographic scale, generally tracking within a city-sized area.

===Valley Committee===
When the [[Soviet Union]] tested [[RDS-1|its first atomic bomb]] in August 1949, the topic of [[air defense]] of the US became important for the first time. A study group, the "Air Defense Systems Engineering Committee" was set up under the direction of Dr. [[George Valley]] to consider the problem, and is known to history as the "Valley Committee".<ref name=valley>
{{cite web
 | title= The Valley Committee
 | website= Lincoln Laboratory
 | date= 1995
 | url= https://www.ll.mit.edu/about/History/origins.html
 | url-status= live
 | archive-url= https://web.archive.org/web/20160401230140/http://www.ll.mit.edu/about/History/origins.html
 | archive-date= 2016-04-01
}}
</ref>

Their December report noted a key problem in air defense using ground-based radars. A bomber approaching a radar station would detect the signals from the radar long before the reflection off the bomber was strong enough to be detected by the station. The committee suggested that when this occurred, the bomber would descend to low altitude, thereby greatly limiting the [[radar horizon]], allowing the bomber to fly past the station undetected. Although flying at low altitude greatly increased [[fuel consumption]], the team calculated that the bomber would only need to do this for about 10% of its flight, making the fuel penalty acceptable.<ref name=valley/>

The only solution to this problem was to build a huge number of stations with overlapping coverage. At that point the problem became one of managing the information. Manual plotting was ruled out as too slow, and a computerized solution was the only possibility. To handle this task, the computer would need to be fed information directly, eliminating any manual translation by phone operators, and it would have to be able to analyze that information and automatically develop tracks.<ref name=valley/> A system tasked with defending cities against the predicted future Soviet bomber fleet would have to be dramatically more powerful than the models used in the NTDS or DATAR.<ref name="Quarterly Progress Report">
{{Cite report
 | title= Quarterly Progress Report
 | date= June 1952
 | publisher= Lincoln Laboratories
}}
 (cited by Schaffel p. 197)
</ref><ref name="web.mit.edu">
{{Cite news
 | title= Physicist George Valley Jr. is dead at 86
 | date= October 20, 1999
 | newspaper= [[MIT Tech Talk]]
 | format= MITnews webpage
 | url= http://web.mit.edu/newsoffice/1999/valley-1020.html
 | access-date= 2012-07-15
 | url-status= live
 | archive-url= https://web.archive.org/web/20121018210958/http://web.mit.edu/newsoffice/1999/valley-1020.html
 | archive-date= October 18, 2012
}}
</ref>

[[File:Museum of Science, Boston, MA - IMG 3168.JPG|thumb|right|Whirlwind computer elements: [[Magnetic-core memory|core memory]] (left) and operator console]]
[[File:Module from a SAGE computer.jpg|right|thumb|Module from a SAGE]]

The Committee then had to consider whether or not such a computer was possible. The Valley Committee was introduced to [[Jerome Wiesner]], associate director of the Research Laboratory of Electronics at [[MIT]]. Wiesner noted that the [[Servomechanisms Laboratory]] had already begun development of a machine that might be fast enough. This was the [[Whirlwind I]], originally developed for the [[Office of Naval Research]]<ref>{{cite web| url = https://www.computer.org/csdl/proceedings-article/afips/1951/50400070/12OmNBvkdmJ| title = Project Whirlwind is a high-speed computer activity sponsored at the Digital Computer Laboratory, formerly a part of the Servomechanisms Laboratory, of the Massachusetts Institute of Technology (MIT) by the US Office of Naval Research (ONR) and the United States Air Force. IEEE Computer Society}}</ref> as a general purpose [[flight simulator]] that could simulate any current or future aircraft by changing its software.<ref name=valley/>

Wiesner introduced the Valley Committee to Whirlwind's project lead, [[Jay Forrester]], who convinced him that Whirlwind was sufficiently capable. In September 1950, an early microwave [[early-warning radar]] system at [[Hanscom Field]] was connected to Whirlwind using a custom interface developed by Forrester's team. An aircraft was flown past the site, and the system digitized the radar information and successfully sent it to Whirlwind. With this demonstration, the technical concept was proven. Forrester was invited to join the committee.<ref name=valley/>

===Project Charles===
With this successful demonstration, [[Louis Ridenour]], chief scientist of the Air Force, wrote a memo stating "It is now apparent that the experimental work necessary to develop, test, and evaluate the systems proposals made by ADSEC will require a substantial amount of laboratory and field effort."<ref name=valley/> Ridenour approached [[Massachusetts Institute of Technology|MIT]] President [[James Killian]] with the aim of beginning a development lab similar to the war-era [[Radiation Laboratory]] that made enormous progress in radar technology. Killian was initially uninterested, desiring to return the school to its peacetime civilian charter. Ridenour eventually convinced Killian the idea was sound by describing the way the lab would lead to the development of a local electronics industry based on the needs of the lab and the students who would leave the lab to start their own companies. Killian agreed to at least consider the issue, and began Project Charles to consider the size and scope of such a lab.<ref name=charles>{{cite web |url= https://www.ll.mit.edu/about/History/projectcharles.html |title= Project Charles |website= Lincoln Laboratory |date= 1995 |url-status= live |archive-url= https://web.archive.org/web/20160224153432/http://www.ll.mit.edu/about/History/projectcharles.html |archive-date= 2016-02-24 }}</ref>

Project Charles was placed under the direction of [[Francis Wheeler Loomis]] and included 28 scientists, about half of whom were already associated with MIT. Their study ran from February to August 1951, and in their final report they stated that "We endorse the concept of a centralized system as proposed by the Air Defense Systems Engineering Committee, and we agree that the central coordinating apparatus of this system should be a high-speed electronic digital computer."<ref name=charles/> The report went on to describe a new lab that would be used for generic technology development for the Air Force, Army and Navy, and would be known as Project Lincoln.<ref name=charles/>

===Project Lincoln===
Loomis took over direction of Project Lincoln and began planning by following the lead of the earlier RadLab. By September 1951, only months after the Charles report, Project Lincoln had more than 300 employees. By the end of the summer of 1952 this had risen to 1300, and after another year, 1800. The only building suitable for classified work at that point was Building 22, suitable for a few hundred people at most, although some relief was found by moving the non-classified portions of the project, administration and similar, to Building 20. But this was clearly insufficient space. After considering a variety of suitable locations, a site at [[Hanscom Air Force Base|Laurence G. Hanscom Field]] was selected, with the groundbreaking taking place in 1951.<ref name=charles/>

The terms of the [[National Security Act of 1947|National Security Act]] were formulated during 1947, leading to the creation of the US Air Force out of the former [[US Army Air Force]]. During April of the same year,  US Air Force staff were identifying specifically the requirement for the creation of automatic equipment for radar-detection which would relay information to an air defence control system, a system which would function without the inclusion of persons for its operation.<ref name="Kent C. Redmond"/> The December 1949 "Air Defense Systems Engineering Committee" led by Dr. [[George Valley]] had recommended computerized networking<ref name="Quarterly Progress Report"/> for "radar stations guarding the northern air approaches to the United States"<ref name="web.mit.edu"/> (e.g., in Canada). <!--In 1949 the USAF had funded [[Project Charles]] to develop a demonstration system for automating Air Defense{{Citation needed|date=July 2011}}--> After a January 1950 meeting, Valley and [[Jay Forrester]] proposed using the [[Whirlwind I]] (completed 1951) for air defense.<ref>{{cite web | url=https://www.technologyreview.com/2015/06/23/167538/the-many-careers-of-jay-forrester/ | title=The Many Careers of Jay Forrester }}</ref> On August 18, 1950, when the "[[1954 Interceptor]]" requirements were issued, the USAF "noted that manual techniques of aircraft warning and control would impose "intolerable" delays"<ref name=Futrell>{{Cite report |last=Futrell |first=Robert Frank |date=June 1971 |title=Ideas, Concepts, Doctrine: A History of Basic Thinking in the United States Air Force 1907–1964 |volume=1 |publisher=Aerospace Studies Institute, Air University}} (cited by Volume I p. 187)</ref>{{rp|484}} ([[Air Materiel Command]] (AMC) published ''Electronic Air Defense Environment for 1954'' in December <!--1950-->.)<ref name=McRee>{{Cite report |last=McRee |first={{Who|reason=McRee's first name needs specified.|date=April 2013}}|date=15 December 1950 |title=…Electronic Air Defense Environment for 1954 |publisher=Headquarters, Air Materiel Command}}</ref>  During February–August 1951 at the new [[Lincoln Laboratory]], the USAF conducted [[Project Claude]] which concluded an improved air defense system was needed.{{Citation needed|reason=data from Lincoln Lab article|date=July 2011}}
[[File:Texas Tower 4.jpg|thumb|250px|right|To increase warning time, radar systems called [[Texas Towers]] were placed in the Atlantic Ocean using technology similar to Texas-style offshore oil platforms]]
In a test for the US military at [[Bedford, Massachusetts]] on 20 April 1951, data produced by a radar was transmitted through telephone lines to a computer for the first time, showing the detection of a mock enemy aircraft. This first test was directed by [[C. Robert Wieser]].<ref name="Kent C. Redmond">{{cite book |url=https://books.google.com/books?id=dxZVbxcf_IoC |author1=Kent C. Redmond  |author2=Thomas M. Smith |name-list-style=amp |title=From Whirlwind to MITRE: The R&D Story of the SAGE Air Defense Computer|publisher=[[MIT Press]] |year=2000 |isbn=978-0-262-26426-6}}(''20th of April 1951'' - p.1, ''National Security Act 1947'' - p.12, ''April 1947'' - p.13)</ref>

The "Summer Study Group" of scientists in 1952 recommended "computerized air direction centers…to be ready by 1954."<ref>{{Cite news |last1=Lapp |last2=Alsop |date=March 21, 1953 |title=We Can Smash the Red A-Bombers |newspaper=Saturday Evening Post |page=19}} (citation 29 of Volume I, p. 25)</ref>

[[International Business Machines|IBM]]'s "Project High" assisted under their October 1952 Whirlwind subcontract with [[Lincoln Laboratory]],{{r|Pugh}}{{rp|210}} and a 1952 USAF [[Project Lincoln]] "fullscale study" of "a large scale integrated ground control system" resulted in the SAGE approval<!--Schaffel p. 207--> "first on a trial basis in 1953".{{r|VolumeI}}{{rp|128}}  The USAF had decided by April 10, 1953, to cancel the competing [[Wizard Program|ADIS]]<!--Schaffel p. 199--> (based on CDS), and the University of Michigan's [[Aeronautical Research Center]] withdrew in the spring.{{r|RedmondSmith}}{{rp|289}} [[Air Research and Development Command]] (ARDC) planned to "finalize a production contract for the Lincoln Transition System".{{r|Schaffel}}{{rp|201}}  Similarly, the July 22, 1953, report by the [[Harold H. Bull|Bull Committee]] ([[United States National Security Council|NSC]] 159) identified completing the [[Mid-Canada Line]] radars as the top priority and "on a second-priority-basis: the Lincoln automated system"<ref>quote from Schaffel p. 191; Condit p. 259 footnote 1 cites: "''CCS 381 US (5-23-46) sec 37.''"</ref>  (the decision to control Bomarc with the automated system was also in 1953.)<ref>{{Cite report |last=McVeigh |first=D. R. |date=January 1956 |title=The Development of the Bomarc Guided Missile 1950–1953 |publisher=Western Air Development Center}} (cited by Volume I p. 108 footnote 69: "''Before the end of 1953, it was also decided that the Sage system being developed by Lincoln Laboratories would be used to control the Bomarc.<sup>69</sup>''")</ref>

The Priority Permanent System with the initial (priority) radar stations was completed in 1952{{r|Schaffel}}{{rp|223}} as a "manual air defense system"<!-- (Col John Morton)--><ref name=IYD/> (e.g., [[North American Aerospace Defense Command|NORAD]]/[[Air Defense Command|ADC]] used a "[[Plexiglas]] plotting board" at the [[Ent Air Force Base|Ent command center]].)<!--{{r|Schaffel}}{{rp|151}}-->  The [[Permanent System radar stations]] included 3 subsequent phases of deployments and by June 30, 1957, had 119 "Fixed CONUS" radars, 29 "Gap-filler low altitude" radars, and 23 control centers".{{r|Condit}}  At "the end of 1957, ADC operated 182 radar stations [and] [[Manual Air Defense Control Center|17 control centers]] … 32 [stations] had been added during the last half of the year as low-altitude, unmanned gap-filler radars.  The total consisted of 47 gap-filler stations, 75 Permanent System radars, 39 semimobile radars, 19 [[Pinetree Line|Pinetree stations]],…1 [[Lashup Radar Network|Lashup -era radar]] and a single [[Texas Tower]]".{{r|Schaffel}}{{rp|223}}  "On 31 December 1958, USAF ADC had 187 operational land-based radar stations" (74 were "P-sites", 29 "M-sites", 13 "SM-sites", & 68 "[[Zone of Interior|ZI]] Gap Fillers").{{r|NORAD1958B}}

==Development==
Systems scientist [[Jay Forrester]] was instrumental in directing the development of the key concept of an interception system during his work at Servomechanisms Laboratory of MIT. The concept of the system, according to the [[Lincoln Laboratory]] site was to 
"develop a digital computer that could receive vast quantities of data from multiple radars and perform real-time processing to produce targeting information for intercepting aircraft and missiles."<ref name="Lincoln Laboratory"/>

[[File:SAGE console.jpeg|right|thumb| The AN/FSQ-7 had 100 system consoles, including the OA-1008 Situation Display (SD) with a [[light gun]] (at end of cable under plastic museum cover), cigarette lighter, and ash tray (left of the light gun).]]

The [[AN/FSQ-7 Combat Direction Central|AN/FSQ-7]] was developed by the Lincoln Laboratory's Digital Computer Laboratory and Division 6, working closely with IBM as the manufacturer. Each FSQ-7 actually consisted of two nearly identical computers operating in "duplex"<ref>{{Cite web|title = MIT Lincoln Laboratory: History:Early Digital Computing (continued)|url = https://www.ll.mit.edu/about/History/digitalcomputing_2.html|website = www.ll.mit.edu|access-date = 2016-01-12|quote = To ensure continuous operation each computer was duplexed; it actually consisted of two machines.|url-status = live|archive-url = https://web.archive.org/web/20151117020231/http://www.ll.mit.edu/about/History/digitalcomputing_2.html|archive-date = 2015-11-17}}</ref> for redundancy. The design used an improved version of the Whirlwind I magnetic core memory and was an extension of the Whirlwind II computer program, renamed AN/FSQ-7 in 1953 to comply with Air Force nomenclature. It has been suggested the FSQ-7 was based on the [[IBM 701]] but, while the 701 was investigated by MIT engineers, its design was ultimately rejected due to high error rates and generally being "inadequate to the task."<ref>{{Cite book|title = From Whirlwind to Mitre: The R&D Story of The SAGE Air Defense Computer|last1 = Redmond|first1 = Kent|publisher = MIT Press|year = 2000|isbn = 978-0262182010|pages = 187–188|last2 = Smith|first2 = Thomas}}</ref> IBM's contributions were essential to the success of the FSQ-7, and IBM benefited immensely from its association with the SAGE project, most evidently during development of the [[IBM 704]].<ref>{{Cite book|title = From Whirlwind to Mitre: The R&D Story of The SAGE Air Defense Computer|last1 = Redmond|first1 = Kent|publisher = MIT Press|year = 2000|isbn = 978-0262182010|pages = 437–438|last2 = Smith|first2 = Thomas}}</ref><ref>{{Cite book|title = AN/FSQ-7: The Computer That Shaped The Cold War|last = Ulmann|first = Bernd|publisher = De Gruyter Oldenbourg|year = 2014|isbn = 9783486727661|pages = 70}}</ref>

On October 28, 1953, the [[Air Force Council]] recommended 1955 funding for "ADC to convert to the Lincoln automated system"{{r|Schaffel}}{{rp|193}}  ("redesignated the '''SAGE System''' in 1954").{{r|Schaffel}}{{rp|201}}  The "''experimental SAGE subsector, located in [[Lexington, Massachusetts|Lexington, Mass.]], was completed in 1955…with a prototype AN/FSQ-7…known as XD-1''"<ref name="Intro" /> (single computer system{{r|SageTalk}} in Building F).{{r|RedmondSmith}}  In 1955, Air Force personnel began IBM training at the [[Kingston, New York]], prototype facility,{{r|EdwardsBenj}} and the "[[4620th Air Defense Wing]] (experimental SAGE) was established at Lincoln Laboratory"

On May 3, 1956, [[Earle E. Partridge|General Partridge]] presented ''[[CINCNORAD]]'s Operational Concept for Control of Air Defense Weapons'' to the [[Armed Forces Policy Council]],{{r|VolumeI}} and a June <!--29, -->1956 symposium presentation identified [[Waterfall model|advanced programming methods]] of SAGE code.<ref>{{Cite journal |author=United States Navy Mathematical Computing Advisory Panel  |date= 29 June 1956 |title=Symposium on advanced programming methods for digital computers |location=Washington, D.C. |publisher =Office of Naval Research, Dept. of the Navy |oclc=10794738 }}</ref>  <!--[[MITRE]] was formed in 1958 to provide oversight and management during deployment, phone lines were by the [[Bell System]], and 500,000 lines of [[assembly language]] were by [[System Development Corporation]].{{Citation needed|date=July 2011}}-->  For SAGE consulting [[Western Electric]] and [[Bell Telephone Laboratories]] formed the [[Air Defense Engineering Service]] (ADES),<ref>{{Cite report |last=McMullen |first=Richard F. |year=1965 |title=The Birth of SAGE, 1951–1958 |volume=ADC Hist Study 33}}  (cited by <!--Volume I p. 271 and--> Schaffel p. 207/312)</ref> which was contracted in January 1954.{{r|RedmondSmith}}  IBM delivered the FSQ-7 computer's prototype in June 1956,<ref name=IBM>{{cite web |work=SAGE: The First [computerized<nowiki>]</nowiki> National Air Defense Network |url=http://www-03.ibm.com/ibm/history/ibm100/us/en/icons/sage/ |title=Overview &#124; |date=7 March 2012 |publisher=IBM.com |access-date=2013-05-08 |quote=the AN/FSQ-7…was developed, built and maintained by IBM. … In June 1956, IBM delivered the prototype of the computer to be used in SAGE. |url-status=dead |archive-url=https://web.archive.org/web/20130512051530/http://www-03.ibm.com/ibm/history/ibm100/us/en/icons/sage/ |archive-date=2013-05-12 }}</ref> and Kingston's XD-2 with dual computers{{r|SageTalk}} guided a [[Cape Canaveral]] BOMARC to a successful aircraft intercept on August 7, 1958.{{r|Schaffel}}{{rp|197}}  Initially contracted to [[RCA]], the AN/FSQ-7 production units were started by IBM in 1958{{Citation needed|date=July 2011}} (32 DCs were planned{{r|Schaffel}}{{rp|207}} for networking NORAD regions.)<ref>{{Cite journal |date=Mar–Apr 1956 |title=SAGE: The New Aerial Defense System of the United States |journal=The Military Engineer}} (cited by Schaffel pp. 311, 332)</ref>  IBM's production contract developed 56 SAGE computers for $.5 billion (~$18 million per computer pair in each FSQ-7){{r|SageTalk}}—[[cf.]] the $2 billion WWII [[Manhattan Project]].

[[General Operational Requirement]]s (GOR) 79 and 97 were "the basic USAF documents guiding development and improvement of [the semi-automatic] ground environment.{{r|NORAD1958A}}{{rp|97}}  Prior to fielding the AN/FSQ-7 centrals, the USAF initially deployed "pre-SAGE semiautomatic intercept systems" ([[General Electric AN/GPA-37 Course Directing Group|AN/GPA-37]]) to [[Air Defense Direction Center]]s, ADDCs{{r|NORAD1958A}}{{rp|11}} (e.g., at "[[NORAD Control Center]]s").{{r|NORAD1958B}}  On April 22, 1958, NORAD approved [[Project Nike|Nike]] [[Army Air Defense Command Post|AADCPs]] to be collocated with the USAF manual ADDCs at [[Duncanville Air Force Station]] TX, [[Olathe Air Force Station]] KS, [[Belleville Air Force Station]] IL, and [[Osceola Air Force Station]] KS.{{r|NORAD1958B}}

==Deployment==
[[File:SAGE CC-1 Hancock Field New York.jpg|thumb|Subsector Command Post of SAGE Combat Center at [[Syracuse Air Force Station]] with consoles and large [[Photographic Display Unit]] display, which was projected from above. Archive photo taken during equipment installation.]]

In 1957, SAGE System groundbreaking at [[McChord Air Force Base|McChord AFB]] was for DC-12<ref>{{cite web |title=Semi-Automatic Ground Environment (SAGE) |url=http://www.globalsecurity.org/wmd/systems/sage.htm |publisher=GlobalSecurity.org |url-status=live |archive-url=https://web.archive.org/web/20130402211322/http://www.globalsecurity.org/wmd/systems/sage.htm |archive-date=2013-04-02 }}</ref> where the "electronic brain" began arriving in November 1958,<ref>{{Cite news |date=November 3, 1958 |title=Electronic Brain Slated To Arrive |url=https://news.google.com/newspapers?id=fxsrAAAAIBAJ&pg=2577,369259&dq=mcchord+sage&hl=en |format=[[Google News Archive]] |newspaper=[[Tri-City Herald]] |access-date=2012-04-02}}</ref> and the "first SAGE regional battle post [CC-01] began operating in Syracuse, New York in early 1959".{{r|Schaffel}}{{rp|263}}  BOMARC "crew training was activated January 1, 1958",{{r|IBM1959B}} and [[AT&T Corporation|AT&T]] "hardened many of its switching centers, putting them in deep underground bunkers",<ref>{{Cite book |title=Getting MAD: Nuclear Mutual Assured Destruction, Its Origins and Practice |publisher=DIANE Publishing |url=https://archive.org/details/bub_gb_9mbWB_UnEy8C|page=[https://archive.org/details/bub_gb_9mbWB_UnEy8C/page/n187 180] |isbn=978-1-4289-1033-1|last1=Sokolski |first1=Henry D|year = 2004}}</ref>  The '''North American Defense Objectives Plan''' (NADOP 59–63) submitted to Canada in December 1958 scheduled 5 Direction Centers and 1 Combat Center to be complete in Fiscal Year 1959, 12 DCs and 3 CCs complete at the end of FY 60, 19 DC/4 CC FY 61, 25/6 FY 62, and 30/10 FY 63.{{r|NORAD1958B}}  On June 30 NORAD ordered that "Air Defense Sectors (SAGE) were to be designated as NORAD sectors",<ref>{{Cite journal |type=NORAD message |date=June 30, 1958 |publisher=North American Air Defense Command }} (identified by NORAD Hist. Summary Jan–Jun '58 p. 7){{nonspecific|reason=The name ("subj:") of the message needs identified in this citation.|date=May 2013}}</ref> (the military reorganization had begun when effective April 1, 1958, [[Continental Air Defense Command|CONAD]] "designated four SAGE sectors – New York, Boston, Syracuse, and Washington – as CONAD Sectors".){{r|NORAD1958A}}{{rp|7}}

[[File:Stewart AFB SAGE center NY1.jpg|thumb|The abandoned SAGE direction center at the former [[Stewart Air Force Base]], New York in 2016]]

SAGE Geographic Reorganization: The '''SAGE Geographic Reorganization Plan''' of July 25, 1958, by NORAD was "to provide a means for the orderly transition and phasing from [[Permanent System radar stations|the manual]] to the SAGE system."  The plan identified deactivation of the [[Eastern Air Defense Force|Eastern]], [[Central Air Defense Force|Central]], and [[Western Air Defense Force|Western Region/Defense Forces]] on July 1, 1960, and "current manual boundaries" were to be moved to the new "eight SAGE divisions" (1 in Canada, "the 35th") as soon as possible.  Manual divisions "not to get SAGE computers were to be phased out" along with their [[Manual Air Defense Control Center]]s at the headquarters base: "9th [at] [[Geiger Field]]… 32d, [[Syracuse AFS]]… 35th, [[Dobbins AFB]]… 58th, [[Wright-Patterson AFB]]… 85th, [[Andrews AFB]]".{{r|NORAD1958B}}  The 26th SAGE Division (New York, Boston, Syracuse & Bangor SAGE sectors)--the 1st of the SAGE divisions—became operational at [[Hancock Field Air National Guard Base|Hancock Field]] on 1 January 1959{{r|NORAD1958B}} after the redesignation started for [[List of United States Air Force aircraft control and warning squadrons|AC&W Squadrons]] (e.g., the [[Highlands Air Force Station|Highlands P-9]] unit became the [[646th Radar Squadron]] (SAGE) October 1.){{r|Johnson}}{{rp|156}}  Additional sectors included the [[Los Angeles Air Defense Sector]] (SAGE) designated in February 1959.  A June 23 JCS memorandum approved the new "March 1959 Reorganization Plan" for HQ NORAD/CONAD/ADC.{{r|NORAD1959A}}{{rp|5}}

[[File:SAGE control room.png|right|thumb| The '''Subsector Command Post''' ("blue room") had personnel on the DC's 3rd floor and a '''Display and Warning Light System''' for the operator environment, e.g., '''Large Board Projection Equipment'''<!--<ref>{{Cite web |title=title tbd |url=http://dome.mit.edu/bitstream/handle/1721.3/40643/MC665_r16_M-4348.pdf?sequence=1 |quote=Large Board Projection Equipment}}</ref>--> projecting from the 4th floor{{r|EdwardsBenj}} (top, [[Cape Cod]] shown on 3rd/4th floor wall) and '''Command Post Digital Display Desk'''<ref name=IBM1959>{{Cite report |date=April 1, 1959 |title=Theory of Programming for AN/FSQ-7 combat direction central and AN/FSQ-8 combat control central |url=http://www.bitsavers.org/pdf/ibm/sage/3-112-0_Theory_Of_Programming_Apr59.pdf |publisher=IBM Military Products Division |page=149 |access-date=2012-04-02 |url-status=live |archive-url=https://web.archive.org/web/20120503131031/http://www.bitsavers.org/pdf/ibm/sage/3-112-0_Theory_Of_Programming_Apr59.pdf |archive-date=May 3, 2012 }}</ref> (center, with operators)]]

[[Project Wild Goose]] teams of [[Air Materiel Command]] personnel installed {{circa|lk=no|1960}} the [[Ground Air Transmit Receive]] stations for the SAGE TDDL (in April 1961, [[Sault Ste Marie Air Defense Sector|Sault Ste Marie]] was the first operational sector with TDDL).<ref name=McMullen1980 /> By the middle of 1960, AMC had determined that about 800,000 [[man-hour]]s (involving 130 changes) would be required to bring the F-106 fleet to the point where it would be a valuable adjunct to the air defense system. Part of the work ([[Project Broad Jump]]) was accomplished by [[Sacramento Air Materiel Area]]. The remainder ([[Project Wild Goose]]) was done at ADC bases by roving AMC field assistance teams supported by ADC maintenance personnel. (cited by Volume I p.&nbsp;271 & Schaffel p.&nbsp;325)  After a September 1959 experimental ATABE test between [[Fort Heath radar station|an "abbreviated" AN/FSQ-7 staged]] at [[Fort Banks (Massachusetts)|Fort Banks]] and the Lexington XD-1, the 1961 "SAGE/[[Missile Master]] test program" conducted large-scale field testing of the ATABE "mathematical model" using radar tracks of actual [[Strategic Air Command|SAC]] and [[Air Defense Command|ADC]] aircraft flying mock penetrations into defense sectors.<ref name=ASD1961>{{Cite report |date=December 1961 |title=A Survey and Summary of Mathematical and Simulation Models as Applied to Weapon System Evaluation |url=http://deepblue.lib.umich.edu/bitstream/2027.42/4298/4/bab9742.0001.001.txt |publisher=[[Aeronautical Systems Center|Aeronautical Systems Division]], USAF |access-date=2011-09-13 |quote=''Data from the Phase II and Phase III [[NORAD]] SAGE/ [[Martin AN/FSG-1 Antiaircraft Defense System|Missile Master]] … to validate the mathematical model ''[with]'' large-scale system tests employing [[Strategic Air Command|SAC]] and [[Aerospace Defense Command|ADC]] aircraft ''[under]'' the NORAD Joint Test Force stationed at [[Stewart Air National Guard Base|Stewart Air Force Base]].'' |url-status=live |archive-url=https://web.archive.org/web/20120424020006/http://deepblue.lib.umich.edu/bitstream/2027.42/4298/4/bab9742.0001.001.txt |archive-date=2012-04-24 }} (cites Miller 1961)</ref>  Similarly conducted was the joint SAC-NORAD [[Operation Skyshield|Sky Shield II exercise followed by Sky Shield III]] on 2 September 1962<ref>{{cite web |title=title tbd |url=http://www.atlasmissilesilo.com/Documents/SquadronUnitHistory/AtlasF/579thSMS/AF-D-O-579-99-RO-00009_6thBombWing_UnitHistory_1962_09_September.pdf |url-status=live |archive-url=https://web.archive.org/web/20130921055807/http://www.atlasmissilesilo.com/Documents/SquadronUnitHistory/AtlasF/579thSMS/AF-D-O-579-99-RO-00009_6thBombWing_UnitHistory_1962_09_September.pdf |archive-date=2013-09-21 }} pdf p. 17</ref>  On July 15, 1963, [[Electronic Systems Division|ESD's]] [[Cheyenne Mountain Complex|CMC]] Management Office assumed "responsibilities in connection with [[BMEWS]], [[Space Track]], SAGE, and BUIC."{{r|DelPapa}}  The [[Chidlaw Building]]'s computerized{{Specify|reason=Was an AN/FSQ-8 used, or did the Chidlaw Combined Operations Center "war room" use the same (or prototype) version of the Burroughs 425L system installed shortly after into the [[Cheyenne Mountain nuclear bunker]] and "fully operational" on April 20, 1966 (Philco 212?) |date=April 2013}} '''[[NORAD/ADC Combined Operations Center]]''' in 1963 became the highest echelon of the SAGE computer network when operations moved from Ent AFB's 1954 manual Command Center to the partially underground{{r|DelPapa}} "war room".<ref>{{cite web |url=http://www.afspc.af.mil/shared/media/document/AFD-070814-023.pdf |title=High Frontier : Volume 3, Number 4 |publisher=Afspc.af.mil |access-date=2013-10-13 |url-status=dead |archive-url=https://web.archive.org/web/20130228051401/http://www.afspc.af.mil/shared/media/document/AFD-070814-023.pdf |archive-date=2013-02-28 }}</ref>  Also in 1963, radar stations were renumbered (e.g., [[Cambria AFS]] was redesignated from P-2 to Z-2 on July 31) and the vacuum-tube SAGE System was completed (and obsolete).{{r|Hellige}}{{Rp|9}}

On "June 26, 1958,…the [[New York Air Defense Sector|New York sector]] became operational"{{r|Schaffel}}{{rp|207}} and on December 1, 1958, the [[Syracuse Air Defense Sector|Syracuse sector's]] DC-03 was operational ("the SAGE system  [did not] become operational until January 1959."){{r|Condit}} Construction of [[CFB North Bay]] in Canada was started in 1959 for a bunker ~{{convert|700|ft|m}} underground (operational October 1, 1963),<ref name=Hazlitt>{{Cite news |last=Hazlitt |first=Tom—[[Southam]] News Services |date=June 5, 1963 |title=The Evolution In Air Defense: NORAD Looks For A Place To Hide |url=https://news.google.com/newspapers?id=rWJkAAAAIBAJ&pg=1034,838096&dq=mcchord+sage&hl=en |newspaper=[[The Calgary Herald]] |access-date=2012-07-15 |quote=The North Bay SAGE centre is the only one on the continent to be fully "hardened", or constructed underground.}}</ref> and by 1963 the system had 3 Combat Centers.  The 23 SAGE centers included 1 in Canada,<ref>{{cite web|title=Many People, One System|url=http://www.computerhistory.org/revolution/networking/19/399|publisher=Computer History Museum|access-date=2013-02-13|url-status=live|archive-url=https://web.archive.org/web/20130206113040/http://www.computerhistory.org/revolution/networking/19/399|archive-date=2013-02-06}}</ref> and the "SAGE control centers reached their full 22 site deployments in 1961 (out of 46 originally planned)."<ref name=Schwartz>{{Cite book |editor=Schwartz, Stephen I. |title=Atomic Audit: The Costs and Consequences of U.S. Nuclear Weapons Since 1940 |url=https://books.google.com/books?id=8droMxkxnDwC&pg=PA284|page=284|isbn=9780815722946 |year=1998 |publisher=Brookings Institution Press }} (the quotation is annotated with footnote 35)</ref>  The completed [[Minot AFB]] blockhouse received an AN/FSQ-7, but never received the FSQ-8 (the April 1, 1959, [[Minot Air Defense Sector]] consolidated with the [[Grand Forks Air Defense Sector|Grand Forks ADS]] on March 1, 1963).<ref>{{Cite web|title=SAGE Documents mapped|url=https://www.radomes.org/museum/sagedocs.html|access-date=2020-10-17|website=www.radomes.org}}</ref><!--Wikipedia article about Minot Air Defense Center has 5 sources-->

===SAGE sites===
The SAGE system included a direction center (DC) assigned to air defense sectors as they were defined at the time.

{| class="wikitable sortable" style="width: 100%"
|+ SAGE Direction Centers
|-
!Site
!Country
!St/Pr
!Location
!Air Defense Sector
!Notes
|-
|XD-1
|[[File:Flag of USA.svg|20px]]USA
|MA
|[[MIT Lincoln Laboratory]] Division 6 Building F in [[Lexington, Massachusetts]]
|experimental SAGE subsector
|prototype completed in October 1955, except for displays.<ref>{{cite web|url=http://dome.mit.edu/bitstream/handle/1721.3/40545/MC665_r15_M-3864.pdf?sequence=1 |title=MC 665 |publisher=dome.mit.edu |access-date=2019-11-29}}</ref>
|-
|DC-01
|[[File:Flag of USA.svg|20px]]USA
|NJ
|[[McGuire Air Force Base|McGuire AFB]]<br><small>{{Coord|40|01|51|N|074|34|32|W|name=SAGE DC-01 (NY sector)}}</small>
|[[New York Air Defense Sector|New York ADS]]
|"June 26, 1958,…the [[New York Air Defense Sector|New York sector]] became operational"{{r|Schaffel}}{{rp|207}}
|-
|DC-02
|[[File:Flag of USA.svg|20px]]USA
|NY
|[[Stewart Air Force Base|Stewart AFB]]<br><small>{{Coord|41|30|01|N|074|06|22|W|name=SAGE DC-02 (Boston sector)}}</small>
|[[Boston Air Defense Sector|Boston ADS]]
|operational June 26, 1958
|-
|DC-03
|[[File:Flag of USA.svg|20px]]USA
|NY
|[[Hancock Field Air National Guard Base|Hancock Field ANG Base]]<br><small>{{Coord|43|07|19|N|076|06|01|W|name=SAGE DC-02 (Syracuse sector)}}</small>
|[[Syracuse Air Defense Sector|Syracuse ADS]]
|operational December 1, 1958
|-
|DC-04
|[[File:Flag of USA.svg|20px]]USA
|VA
|[[Fort Lee Air Force Station|Fort Lee AFS]]<br><small>{{Coord|37|15|09|N|077|19|21|W|name=SAGE DC-04 (Washington sector)}}</small>
|[[Washington Air Defense Sector|Washington ADS]]
|
|-
|DC-05
|[[File:Flag of USA.svg|20px]]USA
|ME
|[[Topsham Air Force Station|Topsham AFS]]<br><small>{{Coord|43|56|42|N|069|57|46|W|name=SAGE DC-05 (Bangor sector)}}</small>
|[[Bangor Air Defense Sector|Bangor ADS]] (BaADS)
|blockhouse demolished 1985<ref name=ColdWarRelics>{{cite web |year=2009 |title=Topsham AFS |url=http://coldwarrelics.com/topsham_afs |archive-url=https://web.archive.org/web/20100612085104/http://coldwarrelics.com/topsham_afs |url-status=dead |archive-date=2010-06-12 |publisher=Cold War Relics |access-date=2013-02-19 |quote=the SAGE block house was bulldozed in 1985. }} (image of entrance sign with arrow: "Bangor North American Air Defense Sector")</ref>
|-
|DC-06
|[[File:Flag of USA.svg|20px]]USA
|MI
|[[Custer Air Force Station|Custer AFS]]<br><small>{{Coord|42|19|18|N|085|16|00|W|name=SAGE DC-06 (Detroit sector)}}</small>
|[[Detroit Air Defense Sector]]
|
|-
|DC-07
|[[File:Flag of USA.svg|20px]]USA
|WI
|[[Truax Field Air National Guard Base|Truax Field ANG Base]]<br><small>{{Coord|43|07|36|N|089|20|06|W|name=SAGE DC-07 (Chicago sector)}}</small>
|[[Chicago Air Defense Sector|Chicago ADS]]
|blockhouse in use as of 2014 as [[Covance]] labs<ref>{{cite web |url= http://www.radomes.org/museum/recent/TruaxFieldWI.html |title= Recent Photos of Truax Field, WI (DC-7/CC-2) |website= radomes.org |access-date= 19 October 2014 |url-status= live |archive-url= https://web.archive.org/web/20150924111005/http://www.radomes.org/museum/recent/TruaxFieldWI.html |archive-date= 24 September 2015 }}</ref>
|-
|DC-08
|[[File:Flag of USA.svg|20px]]USA
|MO
|[[Richards-Gebaur Air Force Base|Richards-Gebaur AFB]]<br><small>{{Coord|38|50|47|N|094|32|50|W|name=SAGE DC-08 (KC sector)}}</small>
|[[Kansas City Air Defense Sector|Kansas City ADS]]
|blockhouse used by BTM Manufacturing
|-
|DC-09
|[[File:Flag of USA.svg|20px]]USA
|AL
|[[Gunter Air Force Base|Gunter AFB]] [[Gunter Annex]]<br><small>{{Coord|32|24|13|N|086|14|28|W|name=SAGE DC-09 (Montgomery sector)}}</small>
|[[Southeast Air Defense Sector|Southeast ADS]] [[Montgomery Air Defense Sector|Montgomery ADS]]
|blockhouse in use as Data Center Montgomery of the Defense Information Systems Agency (DISA), Department of Defense.
|-
|DC-10
|[[File:Flag of USA.svg|20px]]USA
|MN
|[[Duluth Air National Guard Base|Duluth ANG Base]]<br><small>{{Coord|46|50|10|N|092|12|26|W|name=Sage DCC-10 (Duluth sector)}}</small>
|[[Duluth Air Defense Sector|Duluth ADS]]
|blockhouse repurposed for use as office and laboratory space in 1984 by the [[Natural Resources Research Institute]] at the [[University of Minnesota Duluth]]<ref name=Slater2014>{{cite news |author=Brady Slater |title=Talk to shed light on Duluth's history as a Cold War defense hub |url=http://www.duluthnewstribune.com/content/talk-shed-light-duluths-history-cold-war-defense-hub |newspaper=Duluth News-Tribune |date=12 May 2014 |url-status=live |archive-url=https://web.archive.org/web/20160416065438/http://www.duluthnewstribune.com/content/talk-shed-light-duluths-history-cold-war-defense-hub |archive-date=16 April 2016 }}</ref> 
|-
|DC-11
|[[File:Flag of USA.svg|20px]]USA
|ND
|[[Grand Forks Air Force Base|Grand Forks AFB]]<br><small>{{Coord|47|56|47|N|097|22|55|W|name=SAGE DC-11 (Grand Forks sector)}}</small>
|[[Grand Forks Air Defense Sector|Grand Forks ADS]]
|blockhouse demolished
|-
|DC-12
|[[File:Flag of USA.svg|20px]]USA
|WA
|[[McChord Air Force Base|McChord AFB]]<br><small>{{Coord|47|07|18|N|122|30|14|W|name=SAGE DC-12 (Seattle sector)}}</small>
|[[Seattle Air Defense Sector|Seattle]]<br>(now part of [[Western Air Defense Sector|Western ADS]] or WADS)
|
|-
|DC-13
|[[File:Flag of USA.svg|20px]]USA
|OR
|[[Camp Adair|Adair AFS]]<br><small>{{Coord|44|40|15|N|123|12|58|W|name=SAGE DC-13 (Portland sector)}}</small>
|[[Portland Air Defense Sector|Portland ADS]]
|
|-
|DC-14
|[[File:Flag of USA.svg|20px]]USA
|MI
|[[K. I. Sawyer Air Force Base|K.I. Sawyer AFB]]<br><small>{{Coord|46|20|47|N|087|23|00|W|name=SAGE DC-14 (Sault Ste Marie sector)}}</small>
|[[Sault Sainte Marie Air Defense Sector|Sault Sainte Marie ADS]]
|
|-
|DC-15 ?
|[[File:Flag of USA.svg|20px]]USA
| WA
| [[Larson Air Force Base|Larson AFB]]<br><small>{{Coord|47|10|53|N|119|19|16|W|name=SAGE DC-15 (Spokane sector)}}</small>
| [[Spokane Air Defense Sector|Spokane]]
|
|-
|DC-15 ?
|[[File:Flag of USA.svg|20px]]USA
|ME
|[[Bangor Air National Guard Base|Bangor AFB]]
|[[Bangor Air Defense Sector|Bangor ADS]]
|
|-
|DC-16 ?<br>DC-17 ?
|[[File:Flag of USA.svg|20px]]USA
| CA
| [[Norton Air Force Base|Norton AFB]]<br><small>{{Coord|34|06|19|N|117|13|05|W|name=SAGE DC-16 (LA sector)}}</small>
| [[Los Angeles Air Defense Sector|Los Angeles ADS]]
|blockhouse demolished 2018<!-- Norton AFB wikiarticle-->
|-
|DC-16 ?<br>DC-17 ?
|[[File:Flag of USA.svg|20px]]USA
| NV
| [[Stead Air Force Base|Stead AFB]]<br><small>{{Coord|39|39|04|N|119|53|00|W|name=SAGE DC-17 (Reno sector)}}</small>
| [[Reno Air Defense Sector|Reno ADS]]
|
|-
|DC-18
|[[File:Flag of USA.svg|20px]]USA
|CA
|[[Beale Air Force Base|Beale AFB]]<br><small>{{Coord|39|06|35|N|121|23|49|W|name=SAGE DC-18 (San Francisco sector)}}</small>
|[[San Francisco Air Defense Sector|San Francisco ADS]]
|
|-
|DC-19
|[[File:Flag of USA.svg|20px]]USA
|ND
|[[Minot Air Force Base|Minot AFB]]
|[[Minot Air Defense Sector|Minot ADS]]
|site not completed; Minot's blockhouse never had a Q-7<ref>{{cite web |title=title tbd |url=http://www.radomes.org/cgi-bin/museum/acwinfo2x.cgi?site=%22Minot+AFS,+ND%22&key=MinotAFSND&pic=MinotAFSND&doc=MinotAFSND&www=MinotAFSND |access-date=2013-04-01}} (GATR R-19 "was located at Minot AFB" DC-19.)</ref>
|-
|DC-20
|[[File:Flag of USA.svg|20px]]USA
|MT
|[[Malmstrom Air Force Base|Malmstrom AFB]]<br><small>{{Coord|47|30|59|N|111|10|55|W|name=SAGE DC-20 (Great Falls sector)}}</small>
|[[Great Falls Air Defense Sector|Great Falls ADS]]
|
|-
|DC-21
|[[File:Flag of USA.svg|20px]]USA
|AZ
|[[Luke Air Force Base|Luke AFB]]<br><small>{{Coord|33|32|34|N|112|21|27|W|name=SAGE DC-21 (Phoenix sector)}}</small>
|[[Phoenix Air Defense Sector|Phoenix ADS]]
|programming center for all other SAGE sites<ref>{{cite web |last=Murphy |first=Michael F. |title=AN/FSQ7 SAGE Computer: Luke AFB |url=http://www.radomes.org/museum/equip/fsq-7.html |format= personal notes |publisher=Radomes.org |access-date=April 2, 2012 |archive-url=https://web.archive.org/web/20181219033549/https://www.radomes.org/museum/equip/fsq-7.html |archive-date=December 19, 2018 |quote=''Luke center was unique in the fact that it was the programming center for all other sage sites. This only meant that our computers…had more core memory, 32K total''}}</ref>
|-
| DC-22
|[[File:Flag of USA.svg|20px]]USA
| IA
| [[Sioux City Air Force Station|Sioux City AFS]]<br><small>{{Coord|42|23|51|N|096|22|25|W|name=SAGE DC-22 (Sioux City sector)}}</small>
|[[Sioux City Air Defense Sector|Sioux City ADS]]
|operational December 1961, completing the SAGE system;<ref>{{cite web |last=McMullen |first=Richard F. |title=ADC Historical Study No. 35: Command and Control Planning 1958-1965|url=https://www.northcom.mil/Portals/28/Paper%20No%2035%20Command%20and%20Control%20Planning,%201958-1965%20Full%20Release.pdf?ver=2017-03-16-115751-207 |access-date=April 24, 2020 |quote=''[T]he SAGE system was completed in December 1961 when the Sioux City Direction Center became operational.''}}</ref> used AN/FSQ-8 that was retrofitted to have the LRI, GFI, and other components/software specific to the Q-7.{{r|NORAD1958B}}
|-
| DC-23*
|
|
|
|
|
|-
| DC-24*
|
|
|
|
|
|-
| DC-25*
|
|
|
|
|
|-
| DC-26*
|
|
|
|
|
|-
| DC-27*
|
|
|
|
|
|-
| DC-28*
|
|
|
|
|
|-
| DC-29*
|
|
|
|
|
|-
| DC-30*
|
|
|
|
|
|-
| DC-31
| [[File:Flag of Canada.svg|20px]]Canada
| ON
| [[CFB North Bay]]<br><small>{{Coord|46|20|15|N|079|24|42|W|name=SAGE DC-31}}</small>
| [[Goose Air Defense Sector|Goose ADS]]
| operational October 1, 1963
|-
| DC-32*
|
|
|
|
| planned, never completed<!--Schaffel 207--> 
|-
|}
<nowiki>*</nowiki><small>Some of the originally planned 32 DCs were never completed and DCs were planned at installations for additional sectors: [[Calypso Air Force Station|Calypso]]/[[Raleigh, North Carolina|Raleigh]] NC, [[England Air Force Base|England]]/[[Shreveport]] LA, [[Fort Knox]] KY, [[Kirtland Air Force Base|Kirtland]]/[[Albuquerque]] NM, [[Robins Air Force Base|Robins]]/[[Miami Air Defense Sector|Miami]], [[Scott Air Force Base|Scott]]/[[St. Louis]], [[Webb Air Force Base|Webb]]/[[San Antonio]] TX.</small>

==Description==
The environment allowed radar station personnel to monitor the radar data and systems' status (e.g., [[Arctic Tower]] radome pressure) and to use the range height equipment to process height requests from Direction Center (DC) personnel.  DCs received the Long Range Radar Input from the sector's radar stations, and DC personnel monitored the radar tracks and IFF data provided by the stations, requested height-finder radar data on targets, and monitored the computer's evaluation of which fighter aircraft or Bomarc missile site could reach the threat first.  The DC's "NORAD sector commander's operational staff"{{r|FM44}} could designate fighter intercept of a target or, using the '''Senior Director's keyed console'''{{r|SMECC}} in the Weapons Direction room,{{r|EdwardsBenj}} launch a Bomarc intercept with automatic Q-7 guidance of the surface-to-air missile to a final homing dive (equipped fighters eventually were automatically guided to intercepts).

The "NORAD sector direction center (NSDC) [also had] [[Air Defense Artillery Branch|air defense artillery]] director (ADAD) consoles [and an Army] ADA battle staff officer", and the NSDC automatically communicated crosstelling of "SAGE reference track data"<!-- FM44-1 --> to/from adjacent sectors' DCs and to 10 [[Project Nike|Nike]] [[Missile Master]] [[Army Air Defense Command Post|AADCPs]].{{r|FM44}}  Forwardtelling automatically communicated data from multiple DCs to a 3-story Combat Center (CC) usually at one of the sector's DCs{{r|Intro}} ([[cf.]] planned Hamilton AFB CC-05 near the Beale AFB DC-18) for coordinating the air battle in the NORAD region (multiple sectors) and which forwarded data to the NORAD Command Center ([[Ent AFB]], 1963 [[Chidlaw Building]], & 1966 [[Cheyenne Mountain nuclear bunker|Cheyenne Mountain]]). NORAD's integration of air warning data (at the [[Air Defense Operations Center|ADOC]]) along with space surveillance, intelligence, and other data allowed attack assessment of an [[DEFCON|Air Defense Emergency]] for alerting the SAC command centers (465L SACCS nodes at [[Offutt AFB]] & [[Post-Attack Command and Control System Facility, Hadley|The Notch]]), [[The Pentagon]]/[[Raven Rock Mountain Complex|Raven Rock]] [[NMCC]]/ANMCC, and the public via [[CONELRAD]] radio stations.

===<small>SAGE Communication Systems</small>===
{{External media
|image1=[http://www.ieeeghn.org/wiki/index.php/File:Sage_nomination.jpg XD-1 consoles]
|image2=[http://cdn.theatlantic.com/static/mt/assets/science/assets_c/2013/01/sage_situation-thumb-615x672-111531.jpg Situation Display with SAM sites] 
|image6=[http://cdn.theatlantic.com/static/mt/assets/science/assets_c/2013/01/sage_console-thumb-615x349-111527.jpg operator with light gun]
|image7=[http://cdn.theatlantic.com/static/mt/assets/science/assets_c/2013/01/sage_blockhouse-thumb-615x761-111523.jpg room diagrams for each DC floor]
|image8=[https://web.archive.org/web/20071113035819/http://www.456fis.org/Radar_&_Avionics.htm images of a radar scope during a SAGE intercept]
}}
The Burroughs 416L SAGE component ([[Electronic Systems Division|ESD]] Project 416L,{{r|Israel}} Semi Automatic Ground Environment System){{r|DelPapa}} was the [[Cold War]] [[System of systems|network connecting IBM supplied computer system at the various DC and]] that created the display and control environment for operation of the separate radars{{r|Israel}} and to provide outbound [[command guidance]] for ground-controlled interception by air defense aircraft in the "SAGE Defense System"<ref name=YouTube1960>{{cite AV media |year=1960 |title=IBM Sage Computer Ad |url=https://www.youtube.com/watch?v=iCCL4INQcFo |format=digitized film at YouTube |access-date=2013-02-16 |url-status=live |archive-url=https://web.archive.org/web/20130127200223/http://www.youtube.com/watch?v=iCCL4INQcFo |archive-date=2013-01-27 }}</ref> ("Air Defense [[Weapons System]]").<ref name=IBM1959B>{{Cite report |publisher=International Business Machines Corporation |year=1959 |title=The SAGE/Bomarc Air Defense Weapons System: An Illustrated Explanation of What it is and How it Works |url=https://books.google.com/books?id=BFdIGwAACAAJ |format=fact sheet |location=New York|quote=BOMARC…Crew training was activated January 1, 1958. … The operator requests an "engagement prediction point" from the IBM computer. …missile guidance information is relayed via leased lines to Cape Canaveral, and via radio to the BOMARC missile.}} [http://bitsavers.informatik.uni-stuttgart.de/pdf/ibm/sage/SAGE_BOMARC_Defense_System_1958.pdf Alt URL] (cited by Volume I p. 257)</ref> [[Burroughs Corporation]] was a prime contractor for SAGE network interface equipment which included 134 [[Burroughs AN/FST-2 Coordinate Data Transmitting Set]]s (CDTS) at radar stations and other sites, the IBM supplied [[AN/FSQ-7 Combat Direction Central|AN/FSQ-7]] at 23 Direction Centers, and the [[AN/FSQ-8 Combat Control Central|AN/FSQ-8 Combat Control Computers]] at 8 Combat Centers. The 2 computers of each AN/FSQ-7 together weighing {{Convert|275|STf|abbr=on}}<ref>{{Cite journal |last=Colon |first=Raul |title=Early Development of the United States Defensive Missile System |url=http://www.aeroflight.co.uk/military/us_missile.htm |journal=[[Aeroflight]] |url-status=live |archive-url=https://web.archive.org/web/20071106042708/http://www.aeroflight.co.uk/military/us_missile.htm |archive-date=2007-11-06 }}</ref>{{quote without source|reason=A quotation is needed to confirm that Colon gives the weight for the 2 computers instead of the entire AN/FSQ-7, or all the equip (including non-FSQ units) in the DC|date=April 2013}} used about ⅓ of the DC's 2nd floor space{{r|EdwardsBenj}} and at ~$50 per instruction had approximately 125,000 "computer instructions support[ing] actual operational air-defense mission" processing.<ref>{{Cite report |last=Benington |first=Herbert D |url=http://csse.usc.edu/csse/TECHRPTS/1983/usccse83-501/usccse83-501.pdf |access-date=February 18, 2015 |title=Production of Large Computer Programs |type=adaptation of June 1956 presentation |quote=The following paper is a description of the organization and techniques we used at MIT's Lincoln Laboratory in the mid-1950s to produce programs for the SAGE air-defense system. The paper appeared a year before the announcement of SAGE; no mention was made of the specific application other than to indicate that the program was used in a large control system. The programming effort was very large—eventually, close to half a million computer instructions. About one-quarter of these instructions supported actual operational air-defense missions. …  In a letter to me on April 23, 1981 … A Lincoln Utility System of service routines containing 40,000 instructions has been prepared … the experience of the Lincoln Laboratory that a system of service programs equal in size to the main system program must be maintained to support preparation, testing, and maintenance of the latter. |url-status=live |archive-url=https://web.archive.org/web/20150121174748/http://csse.usc.edu/csse/TECHRPTS/1983/usccse83-501/usccse83-501.pdf |archive-date=January 21, 2015 }}</ref>  The AN/FSQ-7 at [[Luke Air Force Base|Luke AFB]] had additional memory (32K total) and was used as a "computer center for all other" DCs.<ref>{{cite web |last=Murphy |first=Michael F. |title=AN/FSQ7 SAGE Computer: Luke AFB |url=http://www.radomes.org/museum/equip/fsq-7.html |format=personal notes |publisher=Radomes.org |access-date=2012-04-02 |quote=Luke center was unique [as] the programming center for all other sage sites [and] had more core memory, 32K total |url-status=live |archive-url=https://web.archive.org/web/20120322033104/http://www.radomes.org/museum/equip/fsq-7.html |archive-date=2012-03-22 }}</ref> Project 416L was the USAF predecessor of NORAD, SAC, and other military organizations' "Big L" computer systems (e.g., 438L [[Air Force Intelligence Data Handling System]] & 496L [[Space Detection and Tracking System]]).<ref>{{Cite book |title=The Closed World: Computers and the Politics of Discourse in Cold War America |via=[[Internet Archive]] |publisher=MIT Press |url=https://archive.org/details/closedworldcompu00edwa|url-access=registration |page=[https://archive.org/details/closedworldcompu00edwa/page/107 107] |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 [[SAC Control System]] (SACCS) [with] over a million lines, reached four times the size of the SAGE code and consumed 1,400 man-years of programming; SDC invented a major computer language, [[JOVIAL]], specifically for this project. |isbn=9780262550284 |last1=Edwards |first1=Paul N |year=1997}}</ref>

Network communications:  {{distinguish|text=[[Worldwide Military Command and Control System|the 1958 "Alert Network Number 1" for NORAD to warn other commands (e.g., "flush" SAC bombers)]]}}  The SAGE network of computers connected by a "Digital Radar Relay"{{r|Edwards1996}} (SAGE data system)<ref>{{Cite journal |last1=Enticknap |first1=R. G. |last2=Schuster |first2=E. F. |year=1958 |title=SAGE Data System Considerations |journal=AIEE Transactions |volume=77 |issue=pt I |pages=824–32 |doi=10.1109/tce.1959.6372899 |s2cid=51659466 }}</ref> used AT&T voice lines, microwave towers, switching centers (e.g., SAGE [[NNX]] 764 was at [[Delta, Utah]]<ref name=Tim>{{cite web |author={{Who|reason=The surname of this author needs specified.|date=February 2013}}, Tim |date=Sep 21, 2007 |title=Re: Speaking of AUTOVON |url=http://dir.groups.yahoo.com/group/coldwarcomms/message/12368 |archive-url=https://archive.today/20130412054503/http://dir.groups.yahoo.com/group/coldwarcomms/message/12368 |url-status=dead |archive-date=April 12, 2013 |format=personal notes |publisher=Yahoo.com (coldwarcomms newsgroup) |access-date=2013-02-18 |quote=A previously referenced AT&T training manual on SAGE/BUIC/AUTOVON phone systems does list all the AUTOVON/SAGE Switching Centers & includes their General Purpose (AUTOVON) NNX, their SAGE NNX, and … For example, [[Delta, Utah]] had 890 for AUTOVON, 764 for SAGE}}</ref>  & 759 at [[Mounds, Oklahoma]]<ref name=message9092>[https://archive.today/20130412051918/http://dir.groups.yahoo.com/group/coldwarcomms/message/9092 Yahoo! Groups]. Dir.groups.yahoo.com. Retrieved on 2013-09-18.</ref>), etc.; and AT&T's "main underground station" was in Kansas (Fairview) with other bunkers in Connecticut (Cheshire), California (Santa Rosa), Iowa (Boone)<ref>{{cite journal |title=CONUS AUTOVON Switching Centers |quote=CO Cheyenne Mountain 1 July 1966…underground (inside mountain) … CO Lamar 1 Jan. 1967 }}</ref> and Maryland ([[Hearthstone Mountain]]).  CDTS [[modem]]s at automated radar stations transmitted range and azimuth,<ref name=FYQ47>{{cite web |title=AN/FYQ-47 Radar Data Processing System |url=http://www.radomes.org/museum/equip/radarequip.php?link=fyq-47.html |publisher=Radomes.org |access-date=2013-02-21 |url-status=live |archive-url=https://web.archive.org/web/20120325045206/http://www.radomes.org/museum/equip/radarequip.php?link=fyq-47.html |archive-date=2012-03-25 }}</ref> and the [[Air Movements Identification Service]] (AMIS) provided air traffic data to the SAGE System.<ref name=Williamson>{{cite web |title=AN/FST-2, RADAR Data Processor/Network System: Gallery |url=http://www.williamson-labs.com/480_cpu22.htm |quote=Air Movements Identification Service (AMIS)  AMIS is responsible for sending [Air Route Traffic Control Center] data on flight plans, weapons status, weather, and aircraft tracks to the Direction and Combat Centers over teletype and voice grade telephone circuits. |url-status=live |archive-url=https://web.archive.org/web/20130123054630/http://www.williamson-labs.com/480_cpu22.htm |archive-date=2013-01-23 }}</ref>  Radar tracks by telephone calls (e.g., from Manual Control Centers in the [[Albuquerque Air Defense Sector|Albuquerque]], [[Minot Air Defense Sector|Minot]], and [[Oklahoma City Air Defense Sector|Oklahoma City]] sectors) could be entered via consoles of the 4th floor "Manual Inputs" room adjacent to the "Communication Recording-Monitoring and VHF" room.<ref>{{Cite journal |publisher=publisher tbd |title=[floor-by-floor diagram of SAGE DC<nowiki>]</nowiki> |url=http://cdn.theatlantic.com/static/mt/assets/science/sage_blockhouse.jpg |type=copy of military diagram in "''[[the Atlantic]]''" |access-date=2013-02-16 |url-status=live |archive-url=https://web.archive.org/web/20130218005343/http://cdn.theatlantic.com/static/mt/assets/science/sage_blockhouse.jpg |archive-date=2013-02-18 }}</ref>  In 1966, SAGE communications were integrated into the [[AUTOVON]] Network.{{r|message9092}}

'''SAGE Sector Warning Networks''' ([[cf.]] NORAD Division Warning Networks) provided the radar netting communications for each DC{{r|NORAD1958B}} and eventually also allowed transfer of [[command guidance]] to autopilots of TDDL-equipped interceptors for vectoring to targets<ref name=Johnson>compiled by {{Cite book |last1=Johnson |first1=Mildred W |date=31 December 1980 |orig-year=February 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 Air Force Base]] |page={{Verify source|date=April 2012}} |access-date=2012-03-26 |url-status=live |archive-url=https://web.archive.org/web/20061123115752/http://www.usafpatches.com/pubs/handbookofadcorg.pdf |archive-date=23 November 2006 }}</ref> via the '''Ground to Air Data Link Subsystem''' and the [[Ground Air Transmit Receive]] (GATR) network of radio sites for "HF/VHF/UHF voice & TDDL"{{r|Tim}} each generally co-located at a CDTS site.  SAGE Direction Centers and Combat Centers were also nodes of NORAD's Alert Network Number 1, and SAC [[Emergency War Order]] Traffic{{r|NORAD1959B}} included "Positive Control/Noah's Ark instructions" through northern NORAD radio sites to confirm or recall SAC bombers if "SAC decided to launch the alert force before receiving an execution order from the JCS".{{r|NORAD1958B}}

A SAGE System [[ergonomic]] test at [[Luke Air Force Base|Luke AFB]] in 1964 "''showed conclusively that the wrong timing of human and technical operations was leading to frequent truncation of the flight path tracking system''" (Harold Sackman).<ref name=Hellige/>{{Rp|9}}  SAGE software development was "grossly underestimated"{{r|RedmondSmith}}{{rp|370}} (60,000 lines in September 1955):<ref>{{cite book|url=https://books.google.com/books?id=3HgQp6f9yGQC&pg=PA158|title=The United States Air Force and the culture of innovation 1945–1965|page= 158|publisher=DIANE |isbn=978-1-4289-9027-2}}</ref>  "the biggest mistake [of] the SAGE computer program was [underestimating the] jump from the 35,000 [[Whirlwind I|[WWI]]] instructions … to the more than 100,000 instructions on the" AN/FSQ-8.<ref>{{Cite report |last=Benington |first=Herbert D. |title=Foreword: Production of Large Computer Programs |url=http://csse.usc.edu/csse/TECHRPTS/1983/usccse83-501/usccse83-501.pdf |access-date=February 18, 2015 |url-status=live |archive-url=https://web.archive.org/web/20150121174748/http://csse.usc.edu/csse/TECHRPTS/1983/usccse83-501/usccse83-501.pdf |archive-date=January 21, 2015 }} (Foreword is part of pdf that includes "[[preface|Editor's Note]]" and a transcript of Benington's 1956 symposium paper beginning with the '''Introduction'''—"This paper looks ahead at some programming problems that are likely to arise during Forrester's 1960–1965 period of real-time control applications."—through '''Summary''': "The techniques that have been developed for automatic programming over the past five years have mostly aimed at simplifying the part of programming that, at first glance, seems toughest—program input, or conversion from programmer language to machine code.")</ref>  NORAD conducted a ''Sage/Missile Master Integration/ECM-ECCM Test'' in 1963,<ref>{{Cite report |publisher=North America Air Defense Command |title=Phase III: Sage/Missile Master Integration/ECM-ECCM Test (Deep River) |location=Ent AFB, Colorado |year=1963}}</ref> and although SAGE used [[Air Movements Identification Service|AMIS]] input of air traffic information, the 1959 plan developed by the July 1958 USAF [[Air Defense Systems Integration Division]]{{r|NORAD1958B}} for [[SAGE Air Traffic Integration]] (SATIN) was cancelled by the DoD.<ref>Missile Master Plan [https://news.google.com/newspapers?nid=1755&dat=19590612&id=tbkcAAAAIBAJ&sjid=DmUEAAAAIBAJ&pg=7467,1893666] [https://news.google.com/newspapers?id=HzY_AAAAIBAJ&sjid=7VAMAAAAIBAJ&pg=3193,5546728&dq=missile-master-plan&hl=en];  identified by Schaffel p. 260: "…the Defense Department to issue, on June 19, 1959, the {{sic|[[Continental Air Defense Program|Master Air Defense Plan]].}}  Key features of the plan included a reduction in BOMARC squadrons, cancellation of plans to upgrade the interceptor force, and a new austere SAGE program.  In addition, funds were deleted for gap-filler and frequency-agility radars.<sup>21 [''1959 NORAD/CONAD Hist Summary: Jan–Jun]</sup>"</ref>

===Radar stations===
[[SAGE radar stations]], including 78 [[DEW Line]] sites in December 1961,<ref>{{Cite journal |last=Furlong |first=R. D. M.  |date=Jun 1974 |title=NORAD—A Study in Evolution |journal=International Defense Review |volume=7 |issue=3 |pages=317–9}} (Schaffel p. 268 citation 39)</ref> provided radar tracks to DCs and had [[Frequency Diversity Radar Program|frequency diversity (FD) radars]]<ref>{{Cite report |year=1955 |title=Project LAMPLIGHT |type=Final Report |location=copy in AF/CHO}} (Schaffel Ch 8 footnote 64 cites this report on pp. 223/312)</ref> [[United States Navy]] [[picket ships]] also provided radar tracks, and seaward radar coverage was provided. By the late 1960s [[EC-121 Warning Star]] aircraft based at [[Otis AFB]] MA and [[McClellan AFB]] CA provided radar tracks via automatic data link to the SAGE System.{{r|Schaffel}}<!--{{rp|220-1}}--> [[Civil Aeronautics Administration (United States)|Civil Aeronautics Administration]] radars were at some stations (e.g., stations of the [[Joint Use Site System]]), and the [[ARSR-1]] [[Air Route Surveillance Radar]] rotation rate had to be modified "for [[Identification friend or foe|SAGE [IFF/SIF] Modes III and IV]]" ("antenna gear box modification" for compatibility with FSQ-7 & FSG-1 centrals.){{r|NORAD1958A}}{{rp|21}}

===Interceptors===
ADC aircraft such as the [[F-94 Starfire]], [[F-89 Scorpion]], [[F-101B Voodoo]], and [[F-4 Phantom]] were controlled by SAGE GCI.  The [[F-104 Starfighter]] was "too small to be equipped with [SAGE] data link equipment" and used voice-commanded GCI,{{r|Schaffel}}{{rp|229}} but the <!--{{r|Schaffel}}{{rp|226}}--> [[F-106 Delta Dart]] was equipped for the [[Tactical Data Links|automated data link (ADL)]].{{Citation needed|date=April 2013}}  The ADL was designed to allow Interceptors that reached targets to transmit real-time tactical friendly and enemy movements and to determine whether sector defence reinforcement was necessary.<ref name="Lincoln Laboratory">{{cite book|url=https://www.ll.mit.edu/about/History/SAGEairdefensesystem.html|author=Lincoln Laboratory|title=The SAGE Air Defense System|publisher=Lincoln Laboratory MIT|access-date=2015-08-05|url-status=live|archive-url=https://web.archive.org/web/20150925190708/https://www.ll.mit.edu/about/History/SAGEairdefensesystem.html|archive-date=2015-09-25|author-link=MIT Lincoln Laboratory}}(this source was also referenced at a time earlier than 2015-08-05, for info: ...ADL... - ''Interceptors'')</ref>

Familiarization flights allowed SAGE weapons directors to fly on two-seat interceptors to observe GCI operations.{{Citation needed|date=May 2013}} [[Surface-to-air missile]] installations for [[CIM-10 Bomarc]] interceptors were displayed on SAGE consoles.<ref>{{cite web |url=http://comptrollerlegal2002.tpub.com/d02658/d026580062.htm |title=Appendix II: Results of Our Analysis 603 Randonmly Selected NDAI Properties Cont |access-date=2013-05-09 |url-status=dead |archive-url=https://web.archive.org/web/20140101030939/http://comptrollerlegal2002.tpub.com/d02658/d026580062.htm |archive-date=2014-01-01 }} [[Formerly Used Defense Site]] C02NY0714</ref>

==Improvements==
{{For|the "Improved SAGE environment"{{r|NORAD1959B}}{{rp|69}} with underground SAGE bunkers (e.g., in the [[Denver Air Defense Sector]]) for the "[[transistor]]ized, solid-state"<!--{{r|Schaffel}}{{rp|264}}--> [[AN/FSQ-32]] systems (never deployed)|Super Combat Center}}
Partially solid-state AN/FST-2B and later <!--[http://www.radomes.org/museum/equip.php  http://tech.groups.yahoo.com/group/USAF-RadarStationVeterans/message/50431 Burroughs AN/FYQ-47 Radar Data Processing System]-->AN/FYQ-47 computers replaced{{When|date=February 2013}} the AN/FST-2,{{r|FYQ47}} and sectors without AN/FSQ-7 centrals requiring a "[[Command, control, and coordination system|weapon direction control device]]" for USAF air defense used the solid-state [[Martin AN/GSG-5 Battery Integration and Radar Display Equipment|AN/GSG-5]] [[Command, control, and coordination system|CCCS]] instead of the [[General Electric AN/GPA-73 Air Weapons Control System|AN/GPA-73]] recommended by ADC in June 1958. [[Back-Up Interceptor Control]] (BUIC){{r|NORAD1958B}} with [[General Electric AN/GPA-37 Course Directing Group|CCCS dispersed to radar stations]] for survivability<!--Schaffel--> allowed a diminished but functional SAGE capability.  In 1962, Burroughs "won the contract to provide a military version of its [[Symmetric multiprocessing#Mid-level systems|D825" modular data processing system]]{{r|SMECC}} for [[Burroughs AN/GSA-51 Radar Course Directing Group|BUIC II]].{{r|Winkler}}<!--p. 44--> BUIC II was first used at [[North Truro Air Force Station|North Truro Z-10]] in 1966,{{r|Winkler}}<!--pdf 54--> and the Hamilton AFB BUIC II was installed in the former [[Manual Air Defense Control Center|MCC building]] when it was converted to a SAGE Combat Center in 1966 (CC-05).<ref name=Page>{{cite web |last=Page |first=Thomas E. |date=June 16, 2009 |title=title tbd |url=http://ed-thelen.org/comp-hist/vs-ibm-sage.html |format=anecdotal message post |publisher=Ed-Thelen.org |access-date=2013-02-21 |url-status=live |archive-url=https://web.archive.org/web/20130303150239/http://ed-thelen.org/comp-hist/vs-ibm-sage.html |archive-date=March 3, 2013 }}</ref>  On June 3, 1963, the Direction Centers at Marysville CA<!-- (DC-05, -17, or -18?)-->, Marquette/K I Sawyer AFB (DC-14) MI<!-- (DC-06 or -14?)-->,{{Specify|reason=Which DCs were at Marysville & Marquett?|date=April 2013}} Stewart AFB NY (DC-02), and Moses Lake WA (DC-15) were planned for closing{{r|Hazlitt}} and at the end of 1969, only 6 CONUS SAGE DCs remained (DC-03, -04, -10, -12, -20, & -21) all with the vacuum tube AN/FSQ-7 centrals.{{r|Winkler}}{{rp|47}}  In 1966, NORAD Combined Operations Center operations at Chidlaw transferred to the [[Cheyenne Mountain Operations Center]] (425L System) and in December 1963, the [[United States Department of Defense|DoD]] approved solid state replacement of [[Martin AN/FSG-1 Antiaircraft Defense System|Martin AN/FSG-1 centrals]]<ref name=LeonardV2>{{Cite book |last=Leonard |first=Barry |year=2011 |title=History of Strategic and Ballistic Missile Defense: Volume II: 1956–1972 |url=http://www.history.army.mil/html/books/bmd/BMDV2.pdf |format=Army.mil PDF - also [https://books.google.com/books?id=HoxycYhoKZkC&pg=PA320 available at Google Books] |access-date=2012-09-01 |quote=The missile and space surveillance and warning system currently{{Specify|The quote in this citation has "currently" for the "space computational center" of 427M that became operational 1979 and was replaced 1992 - Google Books shows a publishing date of 2011, http://www.history.army.mil/catalog/pubs/40/40-5.html shows it as published in 2009.|date=September 2012}} consists of five systems and a space computational center located in the NORAD Cheyenne Mountain complex. The five systems are: the Ballistic Missile Early Warning System; the [[Defense Support Program]] (DSP) formerly called Project 647; the [[Over-the-horizon radar#OTH systems|Forward Scatter over the Horizon Radar]] (440L system); the [[Submarine-launched ballistic missile|Sea-Launched Ballistic Missile Warning System]]; and the [[Space Detection and Warning System]]. … 20 April The 425L system portion of the NORAD [[Cheyenne Mountain Complex]] (NCMC) became fully operational. |url-status=live |archive-url=https://web.archive.org/web/20120921214933/http://www.history.army.mil/html/books/bmd/BMDV2.pdf |archive-date=2012-09-21 }}</ref>{{Rp|317}} with the AN/GSG-5 and subsequent [[Hughes AN/TSQ-51 Air Defense Command and Coordination System|Hughes AN/TSQ-51]]. The "416L/M/N Program Office" at [[Hanscom Field]]<ref name=Israel>{{Cite report |last=Israel |first=David. R. |date=January 1965 |title=System Design and Engineering for Real-Time Military Data Processing Systems |url=http://www.dtic.mil/cgi-bin/GetTRDoc?AD=AD0610392 |format=AD610392, Technical Documentary Report ESD-TDR-64-168, SR-124 |location=Bedford, Massachusetts |publisher=The MITRE Corporation |access-date=2013-04-20 |quote=To be more specific,  I have in mind something like the [[General Electric AN/GPA-73 Air Weapons Control System|BADGE system]];<!--see 1958 July-December NORAD history--> in U.S. experience, examples would be SAGE, [[To be determined|412L]],{{Specify|reason=The name of Program 412L (a lower number than SAGE 416L) needs identified.|date=April 2013}} or the NORAD COC … The early development of SAGE was hampered by the fact that the radars were not considered as a part of the system. |url-status=live |archive-url=https://web.archive.org/web/20130706164513/http://www.dtic.mil/cgi-bin/GetTRDoc?AD=AD0610392 |archive-date=2013-07-06 }}</ref> had deployed the BUIC III by 1971 (e.g., to [[Fallon Naval Air Station|Fallon NAS]]),<ref name=IAODTE>{{Cite report |year=1970 |orig-year=circa |title=Proposed IAO/DTE Resource Availability |quote=An [[Tonopah Air Force Station|Air Force radar facility at Tonopah, Nevada]] is being released by the Air Force to the Federal Aviation Agency. … ADC has a BUIC III radar facility installed and operating at [[Fallon Naval Air Station|Fallon]]. This semi-automated ground environment system permits several other radars to be tied into it.}}</ref> and the initial BUIC systems were phased out 1974–5.{{r|SMECC}}  ADC had been renamed Aerospace Defense Command on January 15, 1968,<ref>{{Cite report |last=McMullen |first=Richard F |year=1973 |title=The Aerospace Defense Command Anti-Bomber Defense, 1946–1962 |url=https://www.google.com/#hl=en&sclient=psy-ab&q=%EF%BB%BFNorth+American+Air+Defense+Command+Historical+Summary:+January+-+June+1958%EF%BB%BF+site%3Awww.northcom.mil&oq=%EF%BB%BFNorth+American+Air+Defense+Command+Historical+Summary:+January+-+June+1958%EF%BB%BF+site%3Awww.northcom.mil&gs_l=serp.3…4665.10015.0.10346.22.22.0.0.0.1.1219.4653.0j18j2j0j1j7-1.22.0…0.0…1c.1.11.psy-ab.PtW1PnDduyg&pbx=1&bav=on.2,or.r_qf.&fp=94c1fca23fa8c111&biw=1600&bih=793 |volume=ADC Hist Study 39 |url-status=live |archive-url=https://web.archive.org/web/20050720082857/http://www.google.com/#hl=en&sclient=psy-ab&q=%EF%BB%BFNorth+American+Air+Defense+Command+Historical+Summary:+January+-+June+1958%EF%BB%BF+site%3Awww.northcom.mil&oq=%EF%BB%BFNorth+American+Air+Defense+Command+Historical+Summary:+January+-+June+1958%EF%BB%BF+site%3Awww.northcom.mil&gs_l=serp.3…4665.10015.0.10346.22.22.0.0.0.1.1219.4653.0j18j2j0j1j7-1.22.0…0.0…1c.1.11.psy-ab.PtW1PnDduyg&pbx=1&bav=on.2,or.r_qf.&fp=94c1fca23fa8c111&biw=1600&bih=793 |archive-date=2005-07-20 }} (cited by Schaffel)</ref> and its general surveillance radar stations transferred to [[Air Defense, Tactical Air Command|ADTAC]] in 1979 when the ADC major command was broken up (space surveillance stations went to SAC and the [[Aerospace Defense Center]] was activated as a [[Direct Reporting Unit|DRU]].)

==Replacement and disposition==

For airborne command posts, "as early as 1962 the Air Force began exploring possibilities for an [[Airborne early warning and control|Airborne Warning and Control System]] (AWACS)",{{r|Schaffel}}{{rp|266}} and the [[Strategic Defense Architecture]] (SDA-2000) planned an integrated air defense and [[air traffic control]] network.  The USAF declared [[full operational capability]] of the first seven [[Joint Surveillance System]] ROCCs on December 23, 1980,{{r|DelPapa}} with Hughes [[AN/FYQ-93]] systems,<ref name=Equip>{{cite web |title=USAF Air Defense Radar Equipment |url=http://www.radomes.org/museum/equip.php |publisher=Online Radar Museum |access-date=2013-02-22 |quote=[[AN/FPS-24]]…Frequency-diverse search radar designed for SAGE [also:] [[AN/FPS-26]]…[[AN/FPS-27]]…[[AN/FPS-28]]…Field tested at [[Houma AFS]], LA |url-status=live |archive-url=https://web.archive.org/web/20130128202438/http://www.radomes.org/museum/equip.php |archive-date=2013-01-28 }}</ref> and many of the SAGE radar stations became [[Joint Surveillance System]] (JSS) sites (e.g., San Pedro Hill Z-39 became FAA [[Ground Equipment Facility J-31]].)  The North Bay AN/FSQ-7 was dismantled and sent to [[The Computer Museum, Boston|Boston's Computer Museum]].{{Citation needed|date=February 2013}} In 1996, AN/FSQ-7 components were moved to [[Moffett Federal Airfield]] for storage and later moved{{When|date=April 2013}}<!-- The year or date of the move from Moffett to the museum needs specified --> to the [[Computer History Museum]] in [[Mountain View, California]].<!--{{Citation needed|date=February 2013}}-->  The last AN/FSQ-7 centrals were demolished at McChord AFB (August 1983) and Luke AFB (February 1984).{{r|SMECC}}  Decommissioned AN/FSQ-7 equipment was also used as science fiction cinema and TV series props (e.g., [[Voyage to the Bottom of the Sea]], amongst others).

==Historiography==
SAGE histories include a 1983 [[special issue]] of the ''Annals of the History of Computing'',{{r|Everett}} and various personal histories were published, e.g., Valley in 1985<ref>{{Cite journal |first=George E. |last=Valley Jr.|year=1985 |title=How the SAGE Development Began |journal=Annals of the History of Computing |volume=7 |issue=3 |pages=196–226 |doi=10.1109/MAHC.1985.10030|s2cid=30320780}}</ref> and Jacobs in 1986.<ref>{{Cite journal |last=Jacobs |first=John F{{Verify source |reason=The middle initial needs verified since the SAGE John Jacobs had middle initial "B".|date=April 2013}} |year=1986 |title=The SAGE Air Defense System: A Personal History |publisher=[[MITRE]] Corporation }}</ref>  In 1998, the SAGE System was identified as 1 of 4 "Monumental Projects",<ref>{{Cite book |last=Hughes |first=Thomas P. Hughes |year=1998 |chapter=SAGE |title=Rescuing Prometheus: Four Monumental Projects That Changed the Modern World |chapter-url=https://books.google.com/books?id=ibDuAAAAMAAJ&q=sage |chapter-format=Google Books |publisher=Pantheon |isbn=9780679411512 |access-date=2013-02-16}}</ref> and a SAGE lecture presented the vintage film ''In Your Defense'' followed by anecdotal information from [[Les Earnest]], [[James Wong (computer scientist)|Jim Wong]], and [[Paul N. Edwards|Paul Edwards]].{{r|SageTalk}}  In 2013, a copy of a 1950s cover girl image programmed for SAGE display was identified as the "earliest known figurative [[computer art]]".{{r|EdwardsBenj}}  Company histories identifying employees' roles in SAGE include the 1981 ''System Builders: The Story of SDC''<ref>{{Cite book |last=Baum |first=Claud |year=1981 |title=System Builders: The Story of SDC |location=Santa Monica |publisher=System Development Corporation}} (cited by Schaffel p. 205/311: "''Although technically a Lincoln unit, SDC did much of its work at RAND Headquarters in Santa Monica, California.  RAND designers developed the Model I software that allowed realistic training for [SAGE] technicians scheduled to operate the first direction center.''")</ref> and the 1998 ''Architects of Information Advantage: The MITRE Corporation Since 1958''.<ref>{{Cite report |last1=Dyer |first1=Davis  |last2=Dennis |first2=Michael Aaron |date=December 1998 |title=Architects of Information Advantage: The MITRE Corporation Since 1958 |publisher=Community Communications Corp |isbn=1581920121 }}</ref>

==See also==
* [[Photographic Display Unit]]

==References==
{{Reflist|25em|refs=
<ref name=Condit>{{Cite report |last=Condit |first=Kenneth W. |year=1992 |orig-year=1971 classified vol |chapter=Chapter 15: Continental Defense |title=The Joint Chiefs of Staff and National Policy: 1955–1956 |volume=VI of <u>History of the Joint Chiefs of Staff</u> |publisher=Historical Office, Joint Staff |location=Washington, D.C. | quote= p. 268 Major elements to be developed to a high state of readiness by the beginning of 1957 included the Distant Early Warning (DEW) Line and an air defense control system employing semiautomatic control centers.1 … At the beginning of 1955, the radar warning systems consisted of 83 permanent radars in the United States, 33 permanent radars of the Pine Tree system in Canada, 12 permanent radars in Alaska, and six shipborne radars stationed off the east coast of the United States. … To facilitate CONAD's job of absorbing data from warning radars and feeding the appropriate instructions to interceptor and antiaircraft forces, the Air Force had sponsored the development of the Semi-Automatic Ground Environment (SAGE) system by the Lincoln Laboratory of the Massachusetts Institute of Technology. The SAGE system was adopted but was not to become operational until January 1959. … the DEW Line…became operational shortly afterward, on 13 Aug 57. … Chapter 15. Continental Defense 1. NSC 5408, 24 Feb 54, CCS 381 US (5-23-46) sec 37.}} (Condit includes detailed numbers of 1954, 1956, and 1957 radar stations on p. 269 Table 13.)</ref>

<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 |number=ESD-TR-88-276 (AD-A201 708) |access-date=2012-07-19 |quote=''Semi-Automatic Direction Center System, later known as…Semi-Automatic Ground Environment System, in essence, the Lincoln Transition System.'' |url-status=live |archive-url=https://web.archive.org/web/20131224105532/http://www.dtic.mil/dtic/tr/fulltext/u2/a201708.pdf |archive-date=2013-12-24 }}</ref>

<ref name=EdwardsBenj>{{Cite journal |last=Edwards |first=Benj |date=January 24, 2013 |title=The Never-Before-Told Story of the World's First Computer Art (It's a Sexy Dame) |url=https://www.theatlantic.com/technology/archive/2013/01/the-never-before-told-story-of-the-worlds-first-computer-art-its-a-sexy-dame/267439/ |journal=[[The Atlantic]] |access-date=2013-02-16 |url-status=live |archive-url=https://web.archive.org/web/20130217134853/http://www.theatlantic.com/technology/archive/2013/01/the-never-before-told-story-of-the-worlds-first-computer-art-its-a-sexy-dame/267439/ |archive-date=February 17, 2013 }}</ref>

<!--([[cf.]] [[radioteletype|RTTY]] art)-->

<!--<ref>{{cite web|url=http://www.metafilter.com/124184/A-picture-is-worth-50000-vacuum-tubes|title=A picture is worth 50,000 vacuum tubes.|access-date=3 October 2014}}</ref>-->

<ref name=Edwards1996>{{Cite book |last=Edwards |first=Paul N |year=1996 |chapter=Chapter 3: SAGE |chapter-url=https://web.archive.org/web/20011116023240/http://www.si.umich.edu/~pne/PDF/cw.ch3.pdf |title=The Closed World: Computers and the Politics of Discourse in Cold War America |url=http://www.si.umich.edu/~pne/cw.htm |location=Cambridge, MA |publisher=MIT Press |page=19 |access-date=2013-04-23 |quote=SAGE – Air Force project 416L – became the pattern for at least twenty-five other major military command-control systems … the [[Air Force Cambridge Research Center]] (AFCRC) [had] recently developed methods for digital transmission of data over telephone lines [with] [[Digital Radar Relay]] (DRR). …was the key issue.<sup>55</sup>  The DRR research, begun just after World War II, had taken four years to complete.  Its availability solved one of the many analog-to-digital conversion problems faced by the eventual SAGE. |url-status=dead |archive-url=https://web.archive.org/web/20011116023240/http://www.si.umich.edu/~pne/cw.htm |archive-date=2001-11-16 }} (Edwards footnote 55 cites Harrington p. 370)</ref>

<ref name=Everett>{{Cite journal |author=Harrington, Jacobs, Tropp|editor=Everett, Robert R |year=1983 |title=Special Issue: SAGE (Semi-Automatic Ground Environment) |journal=Annals of the History of Computing |volume=5 |issue=4|display-authors=etal}}.  Articles include:
:{{Cite journal |last=Harrington |first= John V. |year=1983 |title=Radar Data Transmission |journal=Annals of the History of Computing|volume=5|issue=4 |pages=370–374 |doi=10.1109/MAHC.1983.10100|s2cid= 7227862 }} (cited by Edwards, 1996)
:{{Cite journal |last=Jacobs |first=John B |date=Oct 1983 |title=SAGE Overview |journal=Annals of the History of Computing |volume=5|issue=4 |doi=10.1109/mahc.1983.10101 |pages=323–329|s2cid=154313 }} (cited by Schaffel 310)
:{{Cite journal |last1=Tropp |first1=Henry S. (moderator) |last2=Everett |first2=Robert R.<!--(Everett cited by Schaffel p. 311)--> |year=1983 |title=A Perspective on SAGE: Discussion |journal=Annals of the History of Computing |volume=5|issue=4 |pages=375–98 |doi=10.1109/mahc.1983.10091|s2cid=7490741 |display-authors=etal}} (citation 15 of Edwards, 1996)
:{{Verify source|reason=The Volume & Number need verified to confirm the Astrahan/Jacobs article is in the Special Issue and not a different issue of the journal |date=April 2013}}{{Cite journal |last1=Astrahan |first1=Morton M. |last2=Jacobs |first2=John F. |title=History of the Design of the SAGE Computer, the AN-FSQ-7 |journal=Annals of Computing |page=341 |doi=10.1109/mahc.1983.10098 |volume=5|issue=4 |year=1983 |s2cid=14273110 }} (cited by Schaffel p. 310)</ref>

<ref name=FM44>{{Cite journal |date=February 1963 |title=Missile Master… |type=field manual |volume=FM44-1 |publisher=United States Army |quote=[[Martin AN/FSG-1 Antiaircraft Defense System|AN/FSG-1]] … f.  Utilizes reference track data from local radars and voice communications with the NORAD sector direction center (NSDC) or GC 1 station when SAGE data is unavailable.<!--p. 4--> … 22. Normal Tracking The S & E officers and the trackers monitor the SAGE reference track data<!--p. 14--> …at NORAD SAGE direction centers…personnel operate the air defense artillery director (ADAD) consoles … An Army field grade officer serves as the ADA battle staff officer on the NORAD sector commander's operational staff.<!--p. 17--> … SAGE SELECTOR two-position switch: Selects SAGE 1 or SAGE 2 (primary or secondary SAGE DC) as the source of SAGE data.<!--p. 28--> … 45. Range-Height Subsystem a. Equipment.  The range-height equipment consists of two RHI consoles }}</ref>

<ref name=Hellige>{{Cite report |last=Hellige |first=Hans Dieter |date=February 1993 |title=Actors, Visions and Developments in the History of Computer Communications |url=https://books.google.com/books?id=9A4BHAAACAAJ<!--http://www.artec.uni-bremen.de/team/hellige/HDH-artec-Paper20E.pdf--> |publisher="Work and Technology" Research Centre |access-date=2012-04-02 }}</ref>

<ref name=Intro>{{cite web |title=Introduction |url=http://ed-thelen.org/SageIntro.html |publisher=Ed-Thelen.org |quote=The function of the Control Center in solving the air defense problem is to combine, summarize, and display the air battle picture for the supervision of the several sectors within the division.  … The typical Control Center (CC) building housing the AN/FSQ-8 Combat Control Central is a 3-story structure of the same type construction as the DC building. |url-status=live |archive-url=https://web.archive.org/web/20120403032515/http://ed-thelen.org/SageIntro.html |archive-date=2012-04-03 }} (p. 7)</ref>

<ref name=IYD>{{cite AV media |author=Colonel John Morton (narrator) |title=In Your Defense |url=https://www.youtube.com/watch?v=06drBN8nlWg |format=digitized movie |publisher=Western Electric |access-date=2012-04-03 |quote=''The [[System Development Corporation]]…in the design of massive computer programs … Burroughs…electronic equipment … Western Electric…assist the Air Force in coordinating and managing the entire effort…and design of buildings.   …SAGE project office…Air Material Command'' |url-status=live |archive-url=https://web.archive.org/web/20120703160549/http://www.youtube.com/watch?v=06drBN8nlWg |archive-date=2012-07-03 }}<!-- '''NOTE''': The film identifies "Direction Center" vice "Data Center".<sup>minute 5:15</sup>-->{{When|date=May 2013}}<!-- Is there a year identified in this movie?  --></ref>

<ref name=McMullen1980>{{Cite report |last=McMullen |first=R. F. |date=15 Feb 1980 |title=History of Air Defense Weapons 1946–1962 |volume=ADC Historical Study No. 14 |publisher=Historical Division, Office of information, HQ ADC |page=224}} (cited by Volume I p. 271 & Schaffel p. 325)</ref>

<ref name=NORAD1958A>{{Cite NORAD Historical Summary |version=1958 |access-date=2013-04-30}} <!--|publisher=-->Directorate of Command History: Office of Information Services; p. 21: "''DC's, and CC's, which were to screen and evaluate the reports before forwarding to NORAD headquarters.  ALERT NETWORK NUMBER 1 On 1 July 1958, a new Alert # 1 network was placed in operation (the old network was to remain in operation as a back-up until 1 August 1958).  The new network connected NORAD on 1 July 1958 with 33 Stations that required air defense alert and warning information. This included such agencies as major commands, air divisions, regions, and the USAF Command Post. Only 29 of the stations operating on 1 July were both transmit and receive stations, the other four ([[Tactical Air Command|TAC Headquarters]], [[Sandia Base]], [[Raven Rock Mountain Complex|ADCC (Blue Ridge Summit)]], and the [[Presidio at San Francisco]]) were receive-only stations.  …the new system…gave NORAD the ability to tell which station received its alert messages and which did not.  <!--The new TTY circuits had a built-in automatic sequential authenticator that furnished this information. Previously, NORAD had no knowledge of the effectiveness of its alerting system unless the COC personnel telephoned each individual. receiving station. -->The new system also had two master stations – [[Ent Air Force Base|NORAD [at Ent AFB]]] and the [[ALCOP]] at [[Richards-Gebaur AFB]].  This feature permitted the ALCOP to continue operations of the network and carry on with the alert procedures should NORAD become a war casualty.''"</ref>

<ref name=NORAD1958B>{{Cite NORAD Historical Summary |version=1958b |access-date=2013-04-30}} "''USAF also set down a new schedule (see table preceding). This schedule was to be included in an entirely new SAGE schedule (Schedule A) to be prepared by the '''SAGE Project Office'''. The phasing was to be as follows. The last combat center, AN/FSQ-8, to be installed under SAGE Schedule 7 (Improved), was to be at McChord AFB (25th Air Division).  Subsequent combat facilities and equipment were to be cancelled with the exception of (1) one AN/FSQ-8 that was to be converted to an AN/FSQ-7, using FY 1959 funds, to be installed at the Sioux City DC, and (2) the combat center building at Minot.''" (improved) On April 1, 1966, Combat Center CC-03 at McChord AFB, WA was inactivated in conjunction with the activation of Combat Center CC-05 at Hamilton AFB, CA, and the combining of 25th, 26th and 27th NORAD divisions into the new Headquarters Western NORAD Region at HAFB.  CC-05 utilized a 3-String AN/GSA-51 computer system.  CC-05 and Headquarters Western NORAD Region were inactivated at Hamilton AFB on December 31, 1969.</ref>

<ref name=NORAD1959A>{{Cite NORAD Historical Summary |version=1959 |access-date=2013-04-30}}</ref>

<ref name=NORAD1959B>{{Cite NORAD Historical Summary |version=1959b |access-date=2013-04-30}}</ref>

<ref name=Pugh>{{Cite book |last=Pugh |title=Building IBM: Shaping an Industry and Its Technology |url=https://books.google.com/books?id=Bc8BGhSOawgC&pg=PA210|format=[[Google Books]]|isbn=978-0-262-16147-3|year=1995 |publisher=MIT Press }}</ref>

<ref name=RedmondSmith>{{Cite book |last1=Redmond |first1=Kent C |last2=Smith |first2=Thomas Malcom |year=2000 |title=From Whirlwind to MITRE: The R&D Story of The SAGE Air Defense Computer |url=https://books.google.com/books?id=dxZVbxcf_IoC&q=sage |format=Google Books |publisher=MIT Press |access-date=2013-05-02 |quote=the "SAGE Red Book"--Operationa Plan, Semi-Automatic Ground Environment System for Air Defense (Formerly Designated The Transition System)|isbn=9780262264266 }} (The Redmond & Smith citation for the operation plan identifies the date)</ref>

<ref name=SageTalk>{{cite web |year=1998 |title=Vigilance and Vacuum Tubes: The SAGE System 1956-63 |url=http://ed-thelen.org/Sage-Talk.html |format=SAGE Talk Transcript |publisher=Ed-Thelen.org |access-date=2013-02-16 |quote=the Whirlwind computer, which was a digital version of the [[Airplane Stability and Control Analyzer|ASCA]], was about five million dollars, in 1950s dollars … For the 1949 fiscal year, MIT requested 1.5 million dollars for the Whirlwind project. … one [SAGE computer] was at Lincoln Lab, …the XD-1, and the other one was at Kingston, the XD-2. So we used both those sites for development. … The XD-1 was a simplex system…not duplex … the original vacuum-tube computers—the last one was finally taken down in 1983, still operating. <!--The total cost of the system…between four and twelve billion dollars, in dollars of around 1960 -->… IBM got…about 500 million dollars…to build the 56 computers. |url-status=live |archive-url=https://web.archive.org/web/20130330140132/http://www.ed-thelen.org/Sage-Talk.html |archive-date=2013-03-30 }}</ref>

<ref name=Schaffel>{{cite book|last=Schaffel |first=Kenneth |title=The Emerging Shield: The Air Force and the Evolution of Continental Air Defense, 1945–1960 |url=https://archive.org/details/TheEmergingShield |date=1991 |publisher=Office of Air Force History, United States Air Force |isbn=978-0-912799-60-5 |quote=A SAGE component, a 64 x 64 [4[[kilobyte|K]]] magnetic core memory … SAGE direction center.  This installation is located at Stewart Air Force Base in New York state. …[Hancock Field] combined direction-combat center was located at Syracuse, New York.}} [captions of p. 198, 208, & 265 photos]  '''NOTE''': Schaffel's history uses the same name as "The Emerging Shield: The Air Defense Ground Environment," Air University Quarterly Review 8, no. 2 (spring 1956).</ref>

<!--ref name=SchaffelCh3>{{Cite book |chapter=Chapter 3: Planning for Air Defense in the Postwar Era |title=Emerging Shield |pages=47–81 (pdf pp. 62–96) }}</ref-->

<ref name=SMECC>{{Citation |title=SMECC - Home |url=http://www.smecc.org/ |format=museum website: SMECC.org |location=Glendale, Arizona |publisher=[[Southwest Museum of Engineering, Communications and Computation]] |access-date=2013-05-08 |quote=Archivist Ed Sharpe near some of the SAGE artifacts at SMECC. |url-status=live |archive-url=https://web.archive.org/web/20130524125949/http://smecc.org/ |archive-date=2013-05-24 }}
:a.  {{Cite report |last=DeWerth |first=John P. |title=…Sage Memories |url=http://www.smecc.org/sage_a_n_fsq-7.htm |type=personal notes |publisher=SMECC.org |access-date=2012-04-03 |quote=Senior Director's keyed console…fire button |url-status=live |archive-url=https://web.archive.org/web/20120327032502/http://www.smecc.org/sage_a_n_fsq-7.htm |archive-date=2012-03-27 }}
:b.  {{cite web |title=[AN/GSA-51] |url=http://www.smecc.org/burroughs_buic_-__an_gsa-51__sage_backup.htm |type=system description |publisher=SMECC.org |quote=BUIC … Burroughs…D825 … McChord AFB…August 1983 |url-status=live |archive-url=https://web.archive.org/web/20141003012005/http://www.smecc.org/burroughs_buic_-__an_gsa-51__sage_backup.htm |archive-date=2014-10-03 }}
:c.  {{cite web |title=Phoenix Air Defense Sector |url=http://www.smecc.org/sage-__phoenix_air_defense_sector_%26_4629_support_squadron.htm |type=unit/sector description |publisher=SMECC.org |quote=Luke AFB…February 1984 |url-status=live |archive-url=https://web.archive.org/web/20140103144548/http://www.smecc.org/sage-__phoenix_air_defense_sector_%26_4629_support_squadron.htm |archive-date=2014-01-03 }}</ref>

<ref name=VolumeI>{{Cite book |title=History of Strategic Air and Ballistic Missile Defense: Volume I: 1945–1955 |url=http://www.history.army.mil/html/books/bmd/BMDV1.pdf |format=Army.mil PDF |access-date=2011-09-13 |quote=<!--The 1954 Interceptor, ultimately the F106, was designed to operate within this [SAGE] system.<sup>188</sup> |url-status=live |archive-url=https://web.archive.org/web/20131110121813/http://www.history.army.mil/html/books/bmd/BMDV1.pdf |archive-date=2013-11-10 }} (p. 128, citing "188 Futrell, [''Ideas, Concepts, Doctrine''], pp. 486–487; Grant, [''The Development of Continental Air Defense''] pp. 73–74.") -->}}</ref>

<ref name=Winkler>{{Cite report |last1=Winkler |first1=David F |last2=Webster |first2=Julie L |date=June 1997 |title=Searching the Skies: The Legacy of the United States Cold War Defense Radar Program |url=https://apps.dtic.mil/sti/pdfs/ADA331231.pdf |location=Champaign, IL |lccn=97020912 |publisher=U.S. Army Construction Engineering Research Laboratories |access-date=2013-04-23 |quote=''"BUIC II radar sites would be capable of incorporating data feeds from other radar sectors directly onto their radar screens. '' |url-status=live |archive-url=https://web.archive.org/web/20121201202922/http://www.dtic.mil/cgi-bin/GetTRDoc?Location=U2&doc=GetTRDoc.pdf&AD=ADA331231 |archive-date=2012-12-01 }}</ref>
}}

==Further reading==
* {{cite journal |last1=Enticknap |first1=R. G. |last2=Schuster |first2=E. F. |title=Sage data system considerations |journal=Transactions of the American Institute of Electrical Engineers, Part I: Communication and Electronics |volume=77 |issue=6 |year=1959 |pages=824–832 |issn=0097-2452 |doi=10.1109/TCE.1959.6372899|s2cid=51659466 }}
* [http://ed-thelen.org/sage-1.html Stories about SAGE] - oral history
* [https://scottlocklin.wordpress.com/2013/03/28/the-largest-computer-ever-built/ "The largest computer ever built"] - "Locklin on science"

==External links==
* [https://archive.org/details/OnGuard1956 On Guard: The Story of SAGE] (1956) IBM Corporation, Military Products Division
* {{YouTube|06drBN8nlWg|In Your Defense}} Cold War Computing: The SAGE System, Computer Museum

{{USAF system codes}}

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[[Category:Computer networks]]
[[Category:Computer systems of the United States Air Force]]
[[Category:North American Aerospace Defense Command]]
[[Category:1950s computers]]
[[Category:Computer-related introductions in 1958]]
[[Category:Air defence radar networks]]
[[Category:1950s in technology]]
[[Category:1950s in the United States]]
[[Category:Vacuum tube computers]]