The exact page text, read by your browser's voice.
1947 – 1969
The file system every local case below is checked against: in the summer of 1947, beginning with Kenneth Arnold's sighting of 24 June 1947 over the Cascades, the United States received its first great wave of “flying saucer” reports, and the Air Force answered with a standing investigation in three successive forms, all headquartered at Wright-Patterson Air Force Base in Ohio. Project Sign ran from December 1947 to February 1949; Project Grudge, its scaled-down continuation, to August 1949 (and in reduced form to 1951); and Project Blue Book, ordered in March 1952 by the Director of Intelligence, Major General Charles P. Cabell, ran until Secretary of the Air Force Robert C. Seamans Jr. terminated it on 17 December 1969, operations ending in January 1970. Across the three projects the Air Force investigated 12,618 reports; 701 remained officially unexplained when Blue Book closed. The records were retired to the National Archives in 1975 and opened to public research in 1976, case by case, each file holding the observers' reports, the correspondence, the press clippings, and a control sheet stating the Air Force's own explanation or conclusion. Those control-sheet dispositions — explained, insufficient data, or unidentified — are the verdicts this section prints. Nothing here rests on a retelling where a file exists.
From the National Archives' own statement of the Blue Book record (archives.gov, on the fiftieth anniversary of the project's termination, December 2019): project dates, the 12,618 reports, the 1975 transfer and 1976 opening.