Fortuna Air Force Station

 (1952-1979) - A Cold War Air Force Radar Station first established in 1952 near Fortuna in Divide County, North Dakota. Named Fortuna Air Force Station after the location. Initially assigned a Permanent ID of P-27 and later a Sage ID of Z-27. Abandoned in 1979.

History
Established in 1952 and became operational in April 1952 as Fortuna Air Force Station manned by the 780th AC&W Squadron. The station initially had both a Ground-Control Intercept (GCI) and early warning mission. The early warning mission involved tracking and identifying all aircraft entering their airspace while the GCI mission involved guiding Air Force interceptors to any identified enemy aircraft. Controllers at the station vectored fighter aircraft at the correct course and speed to intercept enemy aircraft using voice commands via ground-to-air radio.

Initial equipment included the FPS-3 search radar and an FPS-4 height-finder radar.

SAGE System Operation


The site began operation as a SAGE site in 1961 initially feeding the Minot SAGE Direction Center DC-19. The search radar was upgraded to an FPS-20A with one FPS-6 and one FPS-6A height-finder radar. In 1963 the FPS-20A was replaced by an FPS-35 and one of the FPS-6s was upgraded to become an FPS-90. In 1963 Fortuna began feeding the Malmstrom SAGE Direction Center DC-20. In 1964 the remaining FPS-6 height-finder was replaced with an FPS-26A.

A violent storm in 1964 destroyed the large FPS-35 radar antenna and put that radar out of commission until a replacement antenna from Manassas Air Force Station was installed a year later. In the interim, an FPS-64 search radar was temporarily installed on the old FPS-20 tower. After a new FPS-35 antenna was installed the FPS-64 was removed. In 1969 the FPS-90 was removed leaving only the FPS-35 and FPS-26A radars.

Both the FPS-35 and the FPS-26A were heavy long-range radars with electronic countermeasures, only 12 of the FPS-35s were built for the Air Force. The location and the radar capabilities assure the longevity of the site and also made it a platform for technology upgrades. As the need for a backup for the SAGE system developed, Fortuna AFS was subsequently chosen to host all thee phases of the SAGE Backup and Intercept Control (BUIC) system. BUIC I was a return to manual intercept control, BUIC II was an interim automated solution while BUIC III was a more capable automated solution.

BUIC System
Technological change came to Fortuna with the BUIC II system and the Burroughs D825 (GSA-51) computer system. The BUIC II system officially went operational at Fortuna on 1 Mar 1966.

Fortuna AFS was selected as a BUIC III site and in 1970 the 780th Radar Squadron (SAGE) became the 780th Air Defense Group (BUIC). The BUIC III system featured a more capable computer, the GSA-51A, and was able to accept inputs from more surveillance radar sites and control larger air defense sectors. The system also brought a replacement of the vacuum tube FST-2 with the solid state FYQ-47 in the early 1970s. As the threat from a Soviet bomber fleet lessened the decision to mothball the BUIC system came in 1974 and the station was closed five years later.

Closure
Fortuna AFS and the 780th Radar Squadron were deactivated on 29 Sep 1979.

Physical Plant
The physical plant of the site was divided into the main site, a cantonment area, two housing areas and a radio site. The main site housed the operations building, the radar towers, and the power plant. The cantonment area housed the enlisted barracks, the bachelor officer's quarters, the orderly room, the dining hall, the motor pool and other support buildings. Apart from the main site were two small housing areas (45 units total) for married personnel.

A separate radio site housed the radio equipment for directing aircraft intercepts.

Current Status
Abandoned in Fortuna, Divide County, North Dakota.

See Also:
 * SAGE System
 * BUIC System
 * Permanent System Radar Sites
 * US Radar Sets
 * Malmstrom SAGE Direction Center DC-20
 * Minot SAGE Direction Center DC-19

Sources:
 * , page 145.
 * , page 86, 168.

Links:
 * Radomes - Fortuna Air Force Station
 * Wikipedia - Fortuna Air Force Station
 * Ghosts of North Dakota - Fortuna Air Force Station