Luke SAGE Direction Center DC-21

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Luke SAGE Direction Center DC-21 (1959-1983) - A Cold War SAGE System Direction Center first established in 1959 on Luke Air Force Base, Phoenix, Maricopa County, Arizona. Named Luke SAGE Direction Center after the location. Assigned a Sage ID of DC-21. Deactivated as a SAGE Direction Center in 1983.

Former Luke SAGE Direction Center DC-21


Established in 1959 and became operational on 15 Feb 1959 as Luke SAGE Direction Center DC-21.

SAGE System Data Flow

Direction center equipment included the duplex FSQ-7 computer system and associated communication equipment. The FSQ-7 computer system assembled digitized inputs from USAF Radar Sites to provide tracking and identification of all aircraft within their sector of responsibility. The digitized radar inputs came from USAF Radar Sites, airborne radar pickets, Texas Towers, Gap Filler Radar Sites and other radar sources. The total picture of aircraft in the sector was assembled and any unknown aircraft were checked out and hostile aircraft were engaged by USAF fighter aircraft, Bomarc missiles or NIKE missiles. The primary defense was against the Soviet threat of a mass nuclear bomber attack on the US. The system evolved before the advent of ICBMs and provided no missile defense against them.

The computer technology was first generation vacuum tube equipment and required significant power and air conditioning. The physical plant of the direction center was enclosed in a large multi-story concrete blockhouse that housed the duplex FSQ-7 computer, communications equipment, a powerhouse, air conditioning systems and operational areas. The operational areas included radar mapping, air surveillance, identification, communications and weapons direction.

The enormous cost of the radar sites, direction centers, personnel, and training caused an immediate reevaluation and almost as quickly as they were built some facilities were closed. The first mass closures began in the 1960s when many radar sites and virtually all the gap filler sites were closed. The first round of direction center closures came in 1963 when six were closed, a second round in 1966 and a third in 1969 that closed a total of 17 out of 23. The remaining six direction centers became SAGE Regional Control Centers (RCCs) still using the massive FSQ-7 vacuum tube computers. As the direction centers and radar sites closed the remaining sites were realigned into ever-increasing sectors.

A new Joint Surveillance System (JSS) evolved as a partnership between the Air Force and the FAA to provide nationwide radar coverage. When completed in 1983 it consisted of only forty-six radar sites feeding into four new Region Operation Control Centers (ROCCs) with FYQ-93 computer systems. With the activation of the four U.S. ROCCs and the two Canadian ROCCs, the last seven of the SAGE direction centers were deactivated and this signaled the end of the SAGE system. Of the remaining forty-six radar sites, thirty-one had FAA-operated search radars and USAF operated height finders. Five sites just had FAA search radars and only ten sites were operated by the Military. With the deployment of forty FAA ARSR-4 3D radar sets in the 1990s, the earlier military and FAA radars were replaced.

The Canadians closed their underground SAGE Direction Center and created two ROCCs (CAN-East and CAN-West) using the FYQ-93 computers in the underground facility.

The Luke SAGE Direction Center was one of the six direction centers designated as a SAGE Regional Control Centers (RCCs) in 1966 and it remained operational, still using the vacuum tube FSQ-7 computer, until 9 Dec 1983.

Luke SAGE Direction Center DC-21 Radar Sites (edit list)
Location Type State Unit ADC NORAD JSS From To GPS Notes
Ajo AFS AZ 612th TM-181 Z-181 1961-05-01 1969-12-31 32.43111,
Mount Lemmon AFS AZ 684th M-92 Z-092 1961-05-01 1969-12-31 32.44167,
Yuma AFS AZ 864th SM-162 Z-162 1961-05-01 1963-04-30 32.65381,
Las Vegas AFS NV 865th SM-163 Z-163 1961-05-01 1969-12-31 36.31861,
Winslow AFS AZ 904th TM-093 Z-093 1961-05-01 1963-08-01 35.08028,
Tonopah AFS NV 866th SM-164 Z-164 1969-09-15 1970-07-01 38.05167,
Almaden AFS CA 862nd M-96 Z-096 1969-09-15 1980-04-01 37.15944,
Boron AFS CA 750th M-59 Z-059 1966-04-01 1975-06-30 35.07889,
Cambria AFS CA 775th P-02 Z-002 1966-04-01 1980-04-01 35.52222,
Fallon AFS NV 858th SM-156 Z-156 1969-09-15 1975-06-30 39.40528,
Lompoc AFS CA 669th RP-015 Z-015 G-35 1966-04-01 1968-06-18 34.56583,
Mill Valley AFS CA 666th P-38 Z-038 J-33 1969-09-15 1980-09-30 37.92389,
Mount Laguna AFS CA 751st P-76 Z-076 J-30 1966-04-01 1970-03-01 32.87667,
Point Arena AFS CA 776th P-37 Z-037 J-34 1969-09-15 1980-09-30 38.88972,
Red Bluff AFS CA 859th SM-157 Z-157 J-62 1969-09-15 1970-09-30 40.14611,
San Pedro Hill AFS CA 670th RP-039 Z-039 J-31 1966-04-01 1976-04-01 33.746111,

Current Status

Sage Direction Center blockhouse repurposed on Luke Air Force Base in Phoenix, Maricopa County, Arizona.

Location: Luke Air Force Base, Phoenix, Maricopa County, Arizona.

Maps & Images

Lat: 33.54278 Long: -112.3575

  • Multi Maps from ACME
  • Maps from Bing
  • Maps from Google
  • Elevation: 1,085'

See Also:


  • Winkler, David F., Searching the Skies: the Legacy of the United States Cold War Defense Radar Program, USAF Hq Air Combat Command, 1997, 192 pages, Pdf, page 100
  • Cornett, Lloyd H. & Johnson, Mildred W., A Handbook of Aerospace Defense Organization (1946-1980), Office of History ADC, Peterson AFB, Colorado, 31 Dec 1980, 179 pages, Pdf, page 58


Visited: 4 Mar 2015

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