Project Blue Book Closes: USAF Ends UFO Investigation

After two decades of investigating flying saucers, the United States Air Force decided there was nothing to see. On December 17, 1969, Secretary of the Air Force Robert Seamans announced the termination of Project Blue Book, the military's official UFO investigation program. The closure followed a University of Colorado study concluding that UFO reports offered nothing of scientific value. Project Blue Book was the third in a series of Air Force UFO programs, following Project Sign in 1947 and Project Grudge in 1949. The modern UFO phenomenon began in June 1947 when pilot Kenneth Arnold reported seeing nine unusual objects near Mount Rainier, Washington. A newspaper account coined "flying saucers," and reports flooded in from across the country. Blue Book operated from 1952 to 1969 under several officers, most notably Captain Edward Ruppelt, who coined "unidentified flying object," and astronomer J. Allen Hynek, who served as scientific consultant. The project investigated 12,618 reported sightings. Of these, 701 remained "unidentified" after analysis. The Condon Report, produced by physicist Edward Condon at the University of Colorado, provided the Air Force its exit strategy. The report concluded that twenty-one years of study had produced "nothing that has added to scientific knowledge" and recommended ending the program. Critics, including Hynek himself, argued that Condon approached the study with a predetermined conclusion and ignored the most compelling cases. Blue Book's files were declassified and transferred to the National Archives in 1976. The closure did not end public interest or government involvement. In 2017, the Pentagon acknowledged a successor program, the Advanced Aerospace Threat Identification Program, and in 2020 the Navy began formally documenting what the military now calls "unidentified aerial phenomena."