ccording to Wikipedia, Project Blue Book was one of a series of systematic studies of Unidentified flying objects (UFOs) conducted by the United States Air Force. Started in 1952, it was the second revival of such a study. A termination order was given for the study in December 1969, and all activity under its auspices ceased in January 1970. This is a quick look at reported UFO sightings in Minneapolis, MN through documents in the USAF Project Blue Book