Semi-Automatic Ground Environment (SAGE)
Photo Archives
The U.S. Air Force contracted MIT physics professor George Valley (inventor
of the radar bombsight) and John Marchetti from the Air Force Cambridge Research
Laboratory ("father" of microwave radar) to develop an early-warning, continent-wide
radar system. When Valley added the Whirlwind digital computer to his radar and
communications system, the SAGE—Semi-Automatic Ground Environment—air defense system was born.
The plan was to create a North American radar perimeter of air defense sectors,
each controlled from a SAGE station with its own Whirlwind computer (plus backup).
In 1957, the first SAGE station became operational. By 1961, the system's 23 sectors
were complete. From the Canadian border to the Arctic Ocean, three radar networks
tracked aircraft, sending radar imagery from the networks to the SAGE stations
over standard telephone lines. The SAGE stations could dispatch interceptor jets
to deal with any and all intruders.
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The referenced photographs on this site are available for you to download from this online collection. High and low resolution files are available for many of them. The photographs may only be used for non-commercial purposes. Please copy the following attribution statement when using the photographs.
Picture used with the permission of The MITRE Corporation.
Copyright © The MITRE Corporation. All Rights Reserved.
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Aerial view of MIT Lincoln Laboratory, Wood St., Lexington,
MA. Blockhouse in foreground housed the AN/FSQ-7 (XD-1) SAGE computer. (Ref. ASC2243-01)
circa 1956
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George Valley ("Father of SAGE"), Director of SAGE, 1952–1958,
speaking to members of the press at announcement of SAGE system for continental
air defense. (Ref. 40yr-p18)
January 16, 1956
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Ret. Adm. Edward L. Cochrane (MIT's vice president for industrial and government relations), Dr. George E. Valley, Maj. Gen. Raymond C. Maude, and Col. Dorr Newton at press conference announcing the SAGE system for continental air defense. (Ref. MC795671)
January 1956
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Cape Cod radar tower in South Truro, MA., was a prototype for the SAGE Air Defense
System. (Ref. BB20)
1959
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SAGE radar in Bath, ME, includes AN/FPS-31 experimental long-range search radar
and AN/FPS-6 height finder radar. (Ref. BB01)
1959 |
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Strobe tracking on a manual plotting board for the Experimental
SAGE Sector (ESS). (Ref. CN92-001)
Circa 1956 |
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Map of Cape Cod system showing principal radar facilities and locations. (Ref.
F-2136)
November 23, 1953
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Floor plan of Cape Cod Direction Center. (Ref. F-2180)
November 27, 1953
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This intercept monitor room in the SAGE Direction Center at MIT's Barta Building in Cambridge, MA., was a prototype for the future national air defense system. (Ref. F-2222)
February 19, 1955
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Vector display with geographical reference marks. A Whirlwind
I computer generates and displays aircraft positions and auxiliary information
on the console. (The direction and length of the vector indicate the aircraft’s
direction and speed.) The operator uses a row of switches below the scope face
to choose the information (e.g., vectors, identification, and track numbers) to
be displayed. In this photo, geographical reference information has been superimposed
on the display in response to a switch control. (Ref. F-1693)
circa 1953
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Typical identification display at a SAGE situation display
console. (Ref. F-2163)
November 23, 1953
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Operator uses special light gun to target potential intercept coordinates.
(Ref. BB10)
circa 1959
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Air Surveillance Officer checking Tracker Initiator Consoles where operators
use light guns to pinpoint tracks. When a blip appears on the scope, the light
beam causes the computer to assign a track number and to relay speed, direction,
and altitude information to various consoles. (Ref. ACS2243-22)
circa 1958
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SAGE Combat Center, Syracuse (NY) Air Force Station. Command post staff communicate with other SAGE sectors, monitor the air battle, and direct weapons. (Ref. BB 6)
1959
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Communication between FSQ-7 and operating personnel via displays, alarms, input switches, display selection switches, and light guns. Normal data processing functions or special operator requests generate information that is stored on display drums for display at various operating positions. Situation display scopes show plan position displays of tracks, flight plans, geography, weapon sites, etc. Digital information displays (smaller scope at upper right of console) show detailed information on selected tracks. The computer "forces" certain displays and alarms to ensure that operators take action. (Ref. F-4946)
1955
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Control room for the FSQ-7 computer equipped with separate
consoles (including standard IBM punched-card units) and magnetic tape units for
each of the duplicate computers. (Ref. BB 11)
circa 1958
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Computer frames of the AN/FSQ-7 IBM SAGE computer (at the
time, one of the world’s largest and most reliable), the heart of the SAGE
system. The frames’ pluggable electronic units performed data processing
for solving air defense problems. Millions of electronic computations, performed
at lightning speed, were continuously checked automatically. Built-in reliability
ensured constant electronic watchfulness 24 hours a day. (Ref. M-0142)
circa 1958
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FSQ-7 magnetic core memory. Central computer was a binary parallel machine
with an 8892-word core memory and a speed of roughly 75,000 single-address instructions/second.
To facilitate processing, numbers representing positional data were stored and
processed as vectors with two 16-bit components. (Ref. BB 13)
1959
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Pluggable units of FSQ-7 arithmetic element frame at SAGE
Direction Center. (Ref. BB 14)
1959
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Rear panel wiring of FSQ-7 arithmetic element frame at SAGE
Direction Center. (Ref. BB 15)
1959
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Air Defense diagram showing relationship of SAGE to national air defense system.
(Ref. RB-p4)
1955
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SAGE building at McGuire Air Force Base. First SAGE air defense center to go
operational. (Ref. M0-183)
circa 1958
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Typical 4-story SAGE Direction Center. 1st floor: Air cooling and
ducting equipment plus telephone frames, cables, and equipment to maintain communication
and radar data flow. Power house attaches to operations part of building by a
common wall. 2nd floor: The SAGE FSQ-7 duplex computers. 3rd floor:
Service area for the operation room above plus office and storage space, the subsector
command post, and the Kelvin-Hughes projector and air-situation display screen.
4th floor: Operational areas where Air Force staff supervised each major air defense
function (weapons direction, identification, air surveillance, etc.) from separate
areas. (Ref. Annals V5N4 p. 326)
circa 1958
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