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Semi-Automatic Ground Environment

Semi-Automatic Ground Environment
"Ground Environment of the CONUS
Air Defense Systems" (1953)[1]
"Electronic Air Defense Environment" (1950)[2]
military C3 human-computer interface
The 4-story SAGE blockhouses with 3.5 acres (1.4 ha) of floor space[3] "were hardened [for] overpressures of" 5 psi (34 kPa).[4]:264 A shorter adjoining building (left) had generators below the 4 intake/exhaust structures on the roof.[5]
Countries United States, Canada

Centers  CC-02:





NY (Hancock Field),
WI (Truax Field),
WA (McChord AFB)[6], NY (Stewart AFB), CA (Hamilton AFB)**, MO (Richards-Gebaur AFB)*, ND Minot AFB*
AZ Luke AFB*
Project Office
Equip. contract
USAF Air Material Command
Western Electric[7]
System Development Corporation[7]
Burroughs Corporation
Operational 1958 June 26 — DC-01
1958 December 1 — DC-03
1959 (early) — CC-01
1966 April 1 — CC-05
AN/FSQ-7 IBM Military Products Division [8]
*Combat Center not completed since AN/FSQ-8 production was halted c. Nov 1958 when Super Combat Centers were planned[6]:26 with AN/FSQ-32s.
**CC-05 at Hamilton AFB, CA utilized a 3-string AN/GSA-51 computer system and was active from Apr 1/66 to Dec 31/69.

The Semi-Automatic Ground Environment (SAGE) was a system of large computers and associated 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. SAGE directed and controlled the NORAD response to a 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 a common prop in movies such as Dr. Strangelove and Colossus.

Powering SAGE were the largest computers ever built, IBM's AN/FSQ-7. Each SAGE Direction Center (DC) contained two FSQ-7's for redundancy, filling two floors of a large cube-shaped concrete building. The upper two floors contained offices, operator stations, and a single two-story radar display visible to most of the DC's personnel. Information was fed to the DC's from a network of radar stations as well as readiness information from various defence sites. The computers, based on the raw radar data, developed "tracks" for the reported targets, and automatically calculated which defences were within range. Subsets of the data were then sent to the many operator consoles, where the operators used light guns to select targets onscreen for further information, select one of the available defences, and issue commands to attack. These commands would then be automatically sent to the defence site via teleprinter. 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 autopilots to maintain an intercept course without operator intervention. Each SAGE DC also forwarded data to a Combat Center (CC) for "supervision of the several sectors within the division"[9] ("each combat center [had] the capability to coordinate defense for the whole nation").[10]:51 Connecting the various sites was an enormous network of telephones, modems and teleprinters.

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 questions about its real ability to deal with large attacks, and several tests by Strategic Air Command bombers suggested the system was "leaky". Nevertheless, SAGE was the backbone of NORADs air defence system into the 1980s, by which time the tube-based FSQ-7's 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.

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).


  • Background 1
  • Development 2
  • Deployment 3
  • Description 4
    • SAGE System 4.1
    • Radar stations 4.2
    • Interceptors 4.3
  • Improvements 5
  • Replacement and disposition 6
  • Historiography 7
  • References 8
  • Further reading 9


Computerized command and control for United States air defense was conceived in July 1945 during the Signal Corps' Project 414A contracted to Bell Laboratories[11]:207 after "employment of an American version of CDS", the British air defense C2 system, had been identified for air defense command and control on June 12.[12] The Priority Permanent System with the initial (priority) radar stations was completed in 1952[4]:223 as a "manual air defense system"[7] (e.g., NORAD/ADC used a "Plexiglas plotting board" at the Ent command center.) 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".[13] At "the end of 1957, ADC operated 182 radar stations [and] 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 stations,…1 Lashup -era radar and a single Texas Tower".[4]: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 "ZI Gap Fillers").[6]

The December 1949 "Air Defense Systems Engineering Committee" led by Dr.

  • R. G. Enticknap and E. F. Schuster, SAGE Data System Considerations, AIEE Transactions vol 77, pt I, 1958 (January 1959 section), pp 824–832.

Further reading

  1. ^ Smith,   (cited by Schaffel p. 202/311, which has "Smith sent…a list of…requirements needed before the Lincoln system could be deployed [by] 1955 [including] filling gaps in radar coverage below 5,000 feet and identifying friend from foe more quickly and reliably.")
  2. ^ a b McRee, (15 December 1950). …Electronic Air Defense Environment for 1954 (Report). Headquarters, Air Materiel Command.
  3. ^ The SAGE Blockhouse - Future Home of the Cold War / Peace Museum. Retrieved on 2013-09-18.
  4. ^ a b c d e f g h i j k l m Schaffel, Kenneth (1991). "Emerging Shield: The Air Force and the Evolution of Continental Air Defense 1945-1960" (45MB pdf). General Histories (Office of Air Force History). ISBN . Retrieved 2011-09-26. "A SAGE component, a 64 x 64 [4K] 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).
  5. ^ a b c d e f Edwards, Benj (January 24, 2013). "…World's First Computer Art…".  
  6. ^ a b c d e f g h i j k l m Preface by Buss, L. H.—Director.  (Report). Directorate of Command History: Office of Information Services. "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.
  7. ^ a b c d Colonel John Morton (narrator) (). In Your Defense (digitized movie). Western Electric. Retrieved 2012-04-03. The  
  8. ^ a b c "Overview |". SAGE: The First [computerized]National Air Defense Network. Retrieved 2013-05-08. 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. 
  9. ^ a b c "Introduction". 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.  (p. 7)
  10. ^ a b c d Winkler, David F; Webster, Julie L (June 1997). Searching the Skies: The Legacy of the United States Cold War Defense Radar Program (Report). Champaign, IL: U.S. Army Construction Engineering Research Laboratories. LCCN 97020912. Retrieved 2013-04-23. ""BUIC II radar sites would be capable of incorporating data feeds from other radar sectors directly onto their radar screens. "
  11. ^ a b c History of Strategic Air and Ballistic Missile Defense: Volume I: 1945-1955 ( PDF). Retrieved 2011-09-13. 
  12. ^ Nelson, Maj Gen Morris R. (June 12, 1950). "subj: Employment of an American Version of CDS" (letter). USAFHRC microfilm  (cited by Schaffel pdf p. 311)
  13. ^ a b Condit, Kenneth W. (1992 [1971 classified vol]). "Chapter 15: Continental Defense". The Joint Chiefs of Staff and National Policy: 1955-1956 (Report). Washington, DC: Historical Office, Joint Staff. (Condit includes detailed numbers of 1954, 1956, and 1957 radar stations on p. 269 Table 13.)
  14. ^ Quarterly Progress Report (Report). Lincoln Laboratories. June 1952. (cited by Schaffel p. 197)
  15. ^ "Physicist George Valley Jr. is dead at 86" (MITnews webpage).  
  16. ^ Futrell, Robert Frank (June 1971). Ideas, Concepts, Doctrine: A History of Basic Thinking in the United States Air Force 1907–1964 (Report). Volume 1. Aerospace Studies Institute, Air University. (cited by Volume I p. 187)
  17. ^ Lapp; Alsop (March 21, 1953). "We Can Smash the Red A-Bombers". Saturday Evening Post. p. 19.  (citation 29 of Volume I, p. 25)
  18. ^ Pugh. Building IBM: Shaping an Industry and Its Technology ( 
  19. ^ a b c d Redmond, Kent C; Smith, Thomas Malcom (2000). From Whirlwind to MITRE: The R&D Story of The SAGE Air Defense Computer (Google Books). MIT Press. Retrieved 2013-05-02. the "SAGE Red Book"--Operationa Plan, Semi-Automatic Ground Environment System for Air Defense (Formerly Designated The Transition System)  (The Redmond & Smith citation for the operation plan identifies the date)
  20. ^ quote from Schaffel p. 191; Condit p. 259 footnote 1 cites: "CCS 381 US (5-23-46) sec 37."
  21. ^ McVeigh, D. R. (January 1956). The Development of the Bomarc Guided Missile 1950–1953 (Report). 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.69")
  22. ^ Serrell, Astrahan, Patterson and Pyne (1997-01-01). "The evolution of computing machines and systems" (cited by Dunmar's Electronic Inventions and Discoveries).   ("production" quotation from Dunmar, which differs from the "prototype" claim)
  23. ^ a b c d "Vigilance and Vacuum Tubes: The SAGE System 1956-63" (SAGE Talk Transcript). 1998. Retrieved 2013-02-16. the Whirlwind computer, which was a digital version of the  
  24. ^ "Topsham AFS". Cold War Relics. copyright 2009. Retrieved 2013-02-19. the SAGE block house was bulldozed in 1985.  (image of entrance sign with arrow: "Bangor North American Air Defense Sector")
  25. ^ "Recent Photos of Truax Field, WI (DC-7/CC-2)". Retrieved 19 October 2014. 
  26. ^ "title tbd". Retrieved 2013-04-01.  (GATR R-19 "was located at Minot AFB" DC-19.)
  27. ^ United States Navy Mathematical Computing Advisory Panel (29 June 1956). "Symposium on advanced programming methods for digital computers". Washington, D.C.: Office of Naval Research, Dept. of the Navy.  
  28. ^ McMullen, Richard F. (1965). The Birth of SAGE, 1951-1958 (Report). ADC Hist Study 33. (cited by Schaffel p. 207/312)
  29. ^ "SAGE: The New Aerial Defense System of the United States". The Military Engineer. Mar–Apr 1956.  (cited by Schaffel pp. 311, 332)
  30. ^ a b c d Preface by Buss, L. H.—Director.  (Report). Directorate of Command History: Office of Information Services. 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 (TAC Headquarters, Sandia Base, 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 system also had two master stations -- 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."
  31. ^ "Semi-Automatic Ground Environment (SAGE)". 
  32. ^ "Electronic Brain Slated To Arrive" ( 
  33. ^ a b ("fact sheet") The SAGE/Bomarc Air Defense Weapons System: An Illustrated Explanation of What it is and How it Works (Report). New York: International Business Machines Corporation. 1959. Archived from the original on 2013-04-23. Retrieved 2013-04-23. "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." (cited by Volume I p. 257)
  34. ^ Sokolski, Henry D. Getting MAD: Nuclear Mutual Assured Destruction, Its Origins and Practice (Google Books).  
  35. ^ "" ("NORAD message"). North American Air Defense Command. June 30, 1958.  (identified by NORAD Hist. Summary Jan-Jun '58 p. 7)
  36. ^ a b compiled by Johnson, Mildred W (31 December 1980) [February 1973 original by Cornett, Lloyd H. Jr]. A Handbook of Aerospace Defense Organization 1946 - 1980.  
  37. ^ Preface by Buss, L. H.—Director.  (Report). Directorate of Command History: Office of Information Services.
  38. ^ McMullen, R. F. (15 Feb 80). History of Air Defense Weapons 1946–1962 (Report). ADC Historical Study No. 14. Historical Division, Office of information, HQ ADC. p. 224. (cited by Volume I p. 271 & Schaffel p. 325)
  39. ^ A Survey and Summary of Mathematical and Simulation Models as Applied to Weapon System Evaluation (Report). Aeronautical Systems Division, USAF. December 1961. Retrieved 2011-09-13. "Data from the Phase II and Phase III NORAD SAGE/ Missile Master … to validate the mathematical model [with] large-scale system tests employing SAC and ADC aircraft [under] the NORAD Joint Test Force stationed at Stewart Air Force Base." (cites Miller 1961)
  40. ^ "title tbd".  pdf p. 17
  41. ^ a b c d Del Papa, Dr. E. Michael; Warner, Mary P. (October 1987). A Historical Chronology of the Electronic Systems Division 1947-1986 (Report). Retrieved 2012-07-19. "Semi-Automatic Direction Center System, later known as…Semi-Automatic Ground Environment System, in essence, the Lincoln Transition System."
  42. ^ "High Frontier : Volume 3, Number 4". Retrieved 2013-10-13. 
  43. ^ a b Hellige, Hans Dieter (Februar [sic] 1993). Actors, Visions and Developments in the History of Computer Communications (Report). "Work and Technology" Research Centre. Retrieved 2012-04-02.
  44. ^ a b Hazlitt, Tom— 
  45. ^ "Many People, One System". Computer History Museum. Retrieved 2013-02-13. 
  46. ^ Schwartz, Stephen I., ed. (1998). Atomic Audit: The Costs and Consequences of U. S. Nuclear Weapons Since 1940.   (the quotation is annotated with footnote 35)
  47. ^ Theory of Programming for AN/FSQ-7 combat direction central and AN/FSQ-8 combat control central (Report). IBM Military Products Division. April 1, 1959. p. 149. Retrieved 2012-04-02.
  48. ^ a b "Missile Master…" (field manual). FM44-1. United States Army. February 1963.  
  49. ^ a b c d SMECC - Home (museum website:, Glendale, Arizona:  
    a. DeWerth, John P.. …Sage Memories (personal notes). Retrieved 2012-04-03. "Senior Director's keyed console…fire button"
    b. "[AN/GSA-51]" (system description). BUIC … Burroughs…D825 … McChord AFB…August 1983 
    c. "Phoenix Air Defense Sector" (unit/sector description). Luke AFB…February 1984 
  50. ^ a b c Israel, David. R. (January 1965) (AD610392, Technical Documentary Report ESD-TDR-64-168, SR-124). System Design and Engineering for Real-Time Military Data Processing Systems (Report). Bedford, Massachusetts: The MITRE Corporation. Retrieved 2013-04-20. "To be more specific, I have in mind something like the BADGE system; in U.S. experience, examples would be SAGE, 412L, 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."
  51. ^ IBM Sage Computer Ad (digitized film at  
  52. ^ Colon, Raul. "Early Development of the United States Defensive Missile System".  
  53. ^ Benington, Herbet D (after 1980) (adaptation of June 1956 presentation). Production of Large Computer Programs (Report). "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."
  54. ^ Murphy, Michael F. "AN/FSQ7 SAGE Computer: Luke AFB" (personal notes). Retrieved 2012-04-02. Luke center was unique [as] the programming center for all other sage sites [and] had more core memory, 32K total 
  55. ^ Edwards, Paul N (1997). The Closed World: Computers and the Politics of Discourse in Cold War America (Google Books).  
  56. ^ Edwards, Paul N (1996). "Chapter 3: SAGE". The Closed World: Computers and the Politics of Discourse in Cold War America. Cambridge, MA: MIT Press. p. 19. Retrieved 2013-04-23. SAGE -- Air Force project 416L -- became the pattern for at least twenty-five other major military command-control systems … the   (Edwards footnote 55 cites Harrington p. 370)
  57. ^ Enticknap, R. G.; Schuster, E. F. (1958). "SAGE Data System Considerations". AIEE Transactions. 77, pt I, 1958 (January 1959 section): 824–32. 
  58. ^ a b , Tim (Sept 21, 2007). "Re: Speaking of AUTOVON" (personal notes). (coldwarcomms newsgroup). Retrieved 2013-02-18. 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,  
  59. ^ a b Yahoo! Groups. Retrieved on 2013-09-18.
  60. ^ "CONUS AUTOVON Switching Centers". CO Cheyenne Mountain 1 July 1966…underground (inside mountain) … CO Lamar 1 Jan. 1967 
  61. ^ a b "AN/FYQ-47 Radar Data Processing System". Retrieved 2013-02-21. 
  62. ^ "AN/FST-2, RADAR Data Processor/Network System". Gallery. 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. 
  63. ^ "[floor-by-floor diagram of SAGE DC]" (copy of military diagram in " 
  64. ^ a b Preface by Buss, L. H.—Director.  (Report). Directorate of Command History: Office of Information Services.
  65. ^ The United States Air Force and the culture of innovation 1945-1965. p. 158. 
  66. ^ Benington, Harold D. (c. 1983) (PDF). Foreword: Production of Large Computer Programs (Report). (Foreward is part of pdf that includes "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.")
  67. ^ Phase III: Sage/Missile Master Integration/ECM-ECCM Test (Deep River) (Report). Ent AFB, Colorado: North America Air Defense Command. 1963.
  68. ^ Missile Master Plan [1] [2]; identified by Schaffel p. 260: "…the Defense Department to issue, on June 19, 1959, the Master Air Defense Plan. [sic] 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.21 [1959 NORAD/CONAD Hist Summary: Jan-Jun]"
  69. ^ Furlong, R. D. M. (Jun 1974). "NORAD--A Study in Evolution". International Defense Review 7, no. 3: 317–9.  (Schaffel p. 268 citation 39)
  70. ^ (Final Report) Project LAMPLIGHT (Report). "copy in AF/CHO". 1955. (Schaffel Ch 8 footnote 64 cites this report on pp. 223/312)
  71. ^ "The SAGE Air Defense System". About | History. fighter aircraft [send] raid assessment information back to the direction center to determine whether additional aircraft or missile intercepts were necessary. 
  72. ^ Formerly Used Defense Site C02NY0714
  73. ^ Page, Thomas E. (June 16, 2009). "title tbd" (anecdotal message post). Retrieved 2013-02-21. 
  74. ^ Leonard, Barry (c. 1986). History of Strategic and Ballistic Missile Defense: Volume II: 1956-1972 ( PDF -- also available at Google Books). Retrieved 2012-09-01. The missile and space surveillance and warning system currently 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  
  75. ^ Proposed IAO/DTE Resource Availability (Report). c. 1970. "An 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. This semi-automated ground environment system permits several other radars to be tied into it."
  76. ^ McMullen, Richard F (1973). The Aerospace Defense Command Anti-Bomber Defense, 1946-1962 (Report). ADC Hist Study 39.…4665.10015.0.10346.…0.0…1c.1.11.psy-ab.PtW1PnDduyg&pbx=1&bav=on.2,or.r_qf.&fp=94c1fca23fa8c111&biw=1600&bih=793. (cited by Schaffel)
  77. ^ "USAF Air Defense Radar Equipment". Online Radar Museum. Retrieved 2013-02-22.  
  78. ^ Harrington, Jacobs, Tropp, et al (1983). Everett, Robert R, ed. "Special Issue: SAGE (Semi-Automatic Ground Environment)". Annals of the History of Computing 5:4. . Articles include:
    Harrington, John V. (1983). "Radar Data Transmission". Annals of the History of Computing, Vol. 5, No. 4 5 (4): 370.   (cited by Edwards, 1996)
    Jacobs, John B (Oct 1983). "SAGE Overview". "Annals of the History of Computing 5, no. 4".  (cited by Schaffel 310)
    Tropp, Henry S. (moderator); Everett, Robert R. et al (1983). "A Perspective on SAGE: Discussion". Annals of the History of Computing, Vol. 5, No. 4. pp. 375–98.  (citation 15 of Edwards, 1996)
    Astrahan, Morton M.; Jacobs, John F. "History of the Design of the SAGE Computer, the AN-FSQ-7". Annals of Computing. p. 341.  (cited by Schaffel p. 310)
  79. ^ Valley Jr., George E. (1985). "How the SAGE Development Began". Annals of the History of Computing, Vol. 7, No. 3 7 (3): 196–226.  
  80. ^ Jacobs, John F (1986). "The SAGE Air Defense System: A Personal History".  
  81. ^ Hughes, Thomas P. Hughes (1998). "SAGE". Rescuing Prometheus: Four Monumental Projects That Changed the Modern World (Google Books). Pantheon. Retrieved 2013-02-16. 
  82. ^ Baum, Claud (1981). System Builders: The Story of SDC. Santa Monica: 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.")
  83. ^ Dyer, Davis; Dennis, Michael Aaron (December 1998). Architects of Information Advantage: The MITRE Corporation Since 1958 (Report). Community Communications Corp.


External media
XD-1 consoles
Situation Display with SAM sites "FOX" & ""BED"
SAGE PPI with entire East Coast
operator with light gun
room diagrams for each DC floor
combined CC/DC at Syracuse (p. 265)
2002 DC-12 photo (McChord/Seattle)
1968 CC-05 Combat Center interior photos (Hamilton AFB, CA)
On Guard: The Story of SAGE on YouTube (1956)[8]
In Your Defense on YouTube

SAGE histories include a 1983 special issue of the Annals of the History of Computing,[78] and various personal histories were published, e.g., Valley in 1985[79] and Jacobs in 1986.[80] In 1998, the SAGE System was identified as 1 of 4 "Monumental Projects",[81] and a SAGE lecture presented the vintage film In Your Defense followed by anecdotal information from Les Earnest, Jim Wong, and Paul Edwards.[23] In 2013, a copy of a 1950s cover girl image programmed for SAGE display was identified as the "earliest known figurative computer art".[5] Company histories identifying employees' roles in SAGE include the 1981 System Builders: The Story of SDC[82] and the 1998 Architects of Information Advantage: The MITRE Corporation Since 1958.[83]


For airborne command posts, "as early as 1962 the Air Force began exploring possibilites for an Airborne Warning and Control System (AWACS)",[4]: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 1st 7 Joint Surveillance System ROCCs on December 23, 1980,[41] with Hughes AN/FYQ-93 systems,[77] and many of the SAGE radar stations became 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 Boston's Computer Museum. In 1996, AN/FSQ-7 components were moved to Moffett Federal Airfield for storage and later moved to the Computer History Museum in Mountain View, California. The last AN/FSQ-7 centrals were demolished at McChord AFB (August 1983) and Luke AFB (February 1984).[49] AN/FSQ-7 equipment was used as TV/movie props (e.g., in Time Tunnel and Voyage to the Bottom of the Sea).

Science fiction author Larry Niven admiring a SAGE console at the Computer History Museum in 2007

Replacement and disposition

Solid-state AN/FST-2B and AN/FYQ-47 computers replaced the AN/FST-2,[61] and sectors without AN/FSQ-7 centrals requiring a "weapon direction control device" for USAF air defense used the solid-state AN/GSG-5 CCCS instead of the AN/GPA-73 recommended by ADC in June 1958. Back-Up Interceptor Control (BUIC)[6] with CCCS dispersed to radar stations for survivability allowed a diminished but functional SAGE capability. In 1962, Burroughs "won the contract to provide a military version of its D825" modular data processing system[49] for BUIC II.[10] BUIC II was 1st used at North Truro Z-10 in 1966,[10] and the Hamilton AFB BUIC II was installed in the former MCC building when it was converted to a SAGE Combat Center in 1966 (CC-05).[73] On June 3, 1963, the Direction Centers at Marysville CA, Marquette/K I Sawyer AFB (DC-14) MI, Stewart AFB NY (DC-02), and Moses Lake WA (DC-15) were planned for closing[44] 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.[10]:47 In 1966, NORAD Combined Operations Center operations at Chidlaw transferred to the Cheyenne Mountain Operations Center (425L System) and in December 1963, the DoD approved solid state replacement of Martin AN/FSG-1 centrals[74]:317 with the AN/GSG-5 and subsequent Hughes AN/TSQ-51. The "416L/M/N Program Office" at Hanscom Field[50] had deployed the BUIC III by 1971 (e.g., to Fallon NAS),[75] and the initial BUIC systems were phased out 1974-5.[49] ADC had been renamed Aerospace Defense Command on January 15, 1968,[76] and its general surveillance radar stations transferred to 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 DRU.)


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,[4]:229 but the F-106 Delta Dart was equipped for the automated data link (ADL). 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.[71] Familiarization flights allowed SAGE weapons directors to fly on two-seat interceptors to observe GCI operations. Surface-to-air missile installations for CIM-10 Bomarc interceptors were displayed on SAGE consoles.[72]


SAGE radar stations, including 78 DEW Line sites in December 1961,[69] provided radar tracks to DCs and had frequency diversity (FD) radars[70] 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.[4] 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 SAGE [IFF/SIF] Modes III and IV" ("antenna gear box modification" for compatibility with FSQ-7 & FSG-1 centrals.)[30]:21

Radar stations

A SAGE System ergonomic test at 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).[43]:9 SAGE software development was "grossly underestimated"[19]:370 (60,000 lines in September 1955):[65] "the biggest mistake [of] the SAGE computer program was [underestimating the] jump from the 35,000 [WWI] instructions … to the more than 100,000 instructions on the" AN/FSQ-8.[66] NORAD conducted a Sage/Missile Master Integration/ECM-ECCM Test in 1963,[67] and although SAGE used AMIS input of air traffic information, the 1959 plan developed by the July 1958 USAF Air Defense Systems Integration Division[6] for SAGE Air Traffic Integration (SATIN) was cancelled by the DoD.[68]

SAGE Sector Warning Networks (cf. NORAD Division Warning Networks) provided the radar netting communications for each DC[6] and eventually also allowed transfer of command guidance to autopilots of TDDL-equipped interceptors for vectoring to targets[36] 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"[58] 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[64] 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".[6]

[59] Network.AUTOVON In 1966, SAGE communications were integrated into the [63] sectors) could be entered via consoles of the 4th floor "Manual Inputs" room adjacent to the "Communication Recording-Monitoring and VHF" room.Oklahoma City, and Minot, Albuquerque Radar tracks by telephone calls (e.g., from Manual Control Centers in the [62] (AMIS) provided air traffic data to the SAGE System.Air Movements Identification Service and the [61] at automated radar stations transmitted range and azimuth,modems). CDTS Hearthstone Mountain and Maryland ([60]), etc.; and AT&T's "main underground station" was in Kansas (Fairview) with other bunkers in Connecticut (Cheshire), California (Santa Rosa), Iowa (Boone)[59]Mounds, Oklahoma & 759 at [58]Delta, Utah 764 was at NNX used AT&T voice lines, microwave towers, switching centers (e.g., SAGE [57] (SAGE data system)[56]Network communications: The SAGE network of computers connected by a "Digital Radar Relay"

The Burroughs 416L SAGE System (Air Force Intelligence Data Handling System & 496L Space Detection and Tracking System).[55]

SAGE System

The "NORAD sector direction center (NSDC) [also had] air defense artillery director (ADAD) consoles [and an Army] ADA battle staff officer", and the NSDC automatically communicated crosstelling of "SAGE reference track data" to/from adjacent sectors' DCs and to 10 Nike Missile Master AADCPs.[48] Forwardtelling automatically communicated data from multiple DCs to a 3-story Combat Center (CC) usually at one of the sector's DCs[9] (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). NORAD's integration of air warning data (at the ADOC) along with space surveillance, intelligence, and other data allowed attack assessment of an Air Defense Emergency for alerting the SAC command centers (465L SACCS nodes at Offutt AFB & The Notch), the Pentagon/Raven Rock NMCC/ANMCC, and the public via CONELRAD radio stations.

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"[48] could designate fighter intercept of a target or, using the Senior Director's keyed console[49] in the Weapons Direction room,[5] 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 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 projecting from the 4th floor[5] (top, Cape Cod shown on 3rd/4th floor wall) and Command Post Digital Display Desk[47] (center, with operators)

On "June 26, 1958,…the New York sector became operational"[4]:207 and on December 1, 1958, the Syracuse sector's DC-03 was operational ("the SAGE system [did not] become operational until January 1959.")[13] Construction of CFB North Bay in Canada was started in 1959 for a bunker ~700 feet (210 m) underground (operational October 1, 1963),[44] and by 1963 the system had 3 Combat Centers. The 23 SAGE centers included 1 in Canada,[45] and the "SAGE control centers reached their full 22 site deployments in 1961 (out of 46 originally planned)."[46] The completed Minot AFB blockhouse never received an AN/FSQ-7 (the April 1, 1959, Minot Air Defense Sector consolidated with the Grand Forks ADS on March 1, 1963).

Project Wild Goose teams of Air Material Command personnel installed c. 1960 the Ground Air Transmit Receive stations for the SAGE TDDL (in April 1961, Sault Ste Marie was the first operational sector with TDDL.)[38] … By the middle of 1960, AMC had determined that about 800,000 manhours (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. 271 & Schaffel p. 325) After a September 1959 experimental ATABE test between an "abbreviated" AN/FSQ-7 staged at 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 SAC and ADC aircraft flying mock penetrations into defense sectors.[39] Similarly conducted was the joint SAC-NORAD Sky Shield II exercise followed by Sky Shield III on 2 September 1962[40] On July 15, 1963, ESD's CMC Management Office assumed "responsibilities in connection with BMEWS, Space Track, SAGE, and BUIC."[41] The Chidlaw Building's computerized 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[41] "war room".[42] 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).[43]:9

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 [37]:5

In 1957, SAGE System groundbreaking at CONAD "designated four SAGE sectors -- New York, Boston, Syracuse, and Washington -- as CONAD Sectors".)[30]:7


Room of SAGE Combat Center at Syracuse Air Force Station with consoles and large display, which was projected from above through the large ceiling opening.

General Operational Requirements (GOR) 79 and 97 were "the basic USAF documents guiding development and improvement of [the semi-automatic] ground environment.[30]:97 Prior to fielding the AN/FSQ-7 centrals, the USAF initially deployed "pre-SAGE semiautomatic intercept systems" (AN/GPA-37) to Air Defense Direction Centers, ADDCs[30]:11 (e.g., at "NORAD Control Centers").[6] On April 22, 1958, NORAD approved Nike 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.[6]

On May 3, 1956, General Partridge presented CINCNORAD’s Operational Concept for Control of Air Defense Weapons to the Armed Forces Policy Council,[11] and a June 1956 symposium presentation identified advanced programming methods of SAGE code.[27] For SAGE consulting Western Electric and Bell Telephone Laboratories formed the Air Defense Engineering Service (ADES),[28] which was contracted in January 1954.[19] IBM delivered the FSQ-7 computer's prototype in June 1956,[8] and Kingston's XD-2 with dual computers[23] guided a Cape Canaveral BOMARC to a successful aircraft intercept on August 7, 1958.[4]:197 Initially contracted to RCA, the AN/FSQ-7 production units were started by IBM in 1958 (32 DCs were planned[4]:207 for networking NORAD regions.)[29] IBM's production contract developed 56 SAGE computers for $½ billion (~$18 million per computer pair in each FSQ-7)[23]cf. the $2 billion WWII Manhattan Project.

1963 SAGE Direction Centers
Sector DC # and site AFB, etc. ST Blockhouse use
New York DC-01   McGuire NJ
Boston DC-02   Stewart NY
Syracuse DC-03   Hancock Field NY
Washington DC-04   Fort Lee AFS VA
Bangor DC-05   Topsham AFS ME demolished 1985[24]
Detroit DC-06   Fort Custer MI
Chicago DC-07   Truax Field WI In use as of 2014 as Covance labs[25]
Kansas City DC-08   Richards-Gebaur MO
Montgomery DC-09   Gunter AL
Duluth DC-10   Duluth IAP MN
Grand Forks DC-11   Grand Forks ND demolished
Seattle DC-12   McChord WA
Portland DC-13   Adair AFS OR
Sault Ste Marie DC-14   K. I. Sawyer MI
Spokane DC-15   Larson WA
Los Angeles DC-16   Norton CA abandoned
Reno DC-17   Stead NV
San Francisco DC-18   Beale CA
Minot DC-19[26] (not completed)
Minot ND
Great Falls DC-20   Malmstrom MT
Phoenix DC-21   Luke AZ
Sioux City DC-22**   Sioux City AFS IA
DC-31   CFB North Bay ON
*Some of the originally planned 32 DCs were never completed, e.g., Minot's blockhouse never had a Q-7,
and DCs were planned at installations for additional sectors: Calypso/Raleigh NC, England/
Shreveport LA, Fort Knox KY, Kirtland/Albuquerque NM, Robins/Miami, Scott/St. Louis, Webb/San Antonio TX.
*The DC-22 AN/FSQ-7 was an AN/FSQ-8 that was retrofitted to have the LRI, GFI, and other components/software specific to the Q-7.[6]

The 2 computers in each AN/FSQ-7 were based on the IBM 701,[22] used an improved version of the Whirlwind I magnetic core memory. On October 28, 1953, the Air Force Council recommended 1955 funding for "ADC to convert to the Lincoln automated system"[4]:193 ("redesignated the SAGE System in 1954").[4]:201 The "experimental SAGE subsector, located in Lexington, Mass., was completed in 1955…with a prototype AN/FSQ-7…known as XD-1"[9] (single computer system[23] in Building F).[19] In 1955, Air Force personnel began IBM training at the Kingston, New York, prototype facility,[5] and the "4620th Air Defense Wing (experimental SAGE) was established at Lincoln Laboratory"


IBM's "Project High" assisted under their October 1952 Whirlwind subcontract with Lincoln Laboratory,[18]:210 and a 1952 USAF Project Lincoln "full­scale study" of "a large­ scale integrated ground control system" resulted in the SAGE approval "first on a trial basis in 1953".[11]:128 The USAF had decided by April 10, 1953, to cancel the competing ADIS (based on CDS), and the University of Michigan’s Aeronautical Research Center withdrew in the spring.[19]:289 ARDC planned to "finalize a production contract for the Lincoln Transition System".[4]:201 Similarly, the July 22, 1953, report by the Bull Committee (NSC 159) identified completing the Mid-Canada Line as the top priority and "on a second-priority-basis: the Lincoln automated system"[20] (the decision to control Bomarc with the automated system was also in 1953.)[21]

[17] which concluded an improved air defense system was needed. The "Summer Study Group" of scientists in 1952 recommended "computerized air direction centers…to be ready by 1954."Project Claude, the USAF conducted Lincoln Laboratory During February–August 1951 at the new [2] in December .)Electronic Air Defense Environment for 1954 published AMC (:484[16]" requirements were issued, the USAF "noted that manual techniques of aircraft warning and control would impose “intol­erable” delays"1954 Interceptor (completed 1951) for air defense. On August 18, 1950, when the "Whirlwind I proposed using the Jay Forrester (e.g., in Canada). After a January 1950 meeting, Valley and [15] for "radar stations guarding the northern air approaches to the United States"[14]

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