Northern Tier Air Force Bases

  Strategic missile line

Malmstrom, Minot, Grand Forks, and Wurtsmith Air Force Bases formed a belt protecting United States northern airspace with Minuteman ICBMs and B-52 bombers.

  Wave of 1966–1975 anomalies

Security teams reported disc-shaped lights hovering above missile silos, causing guidance system faults and temporary loss of launch control. Radar operators tracked targets performing right-angle turns at Mach 3 without altitude loss.¹ See the SAC base intrusions file for declassified communications.

  Investigative response

Air Force Office of Special Investigations dispatched teams while Project Blue Book filed incidents under "Northern Tier sightings." Classified teletype messages reveal Strategic Air Command ordered increased Alert Condition Bravo after simultaneous incursions on 24 October 1975.

  References

1. NORAD Command Message 31-75, declassified 2006-11-02. ↩