File 024 · 1952–1969 · UFO investigations

Project Blue Book

The US Air Force investigated more than 12,000 UFO reports. Blue Book closed in 1969 saying it found no evidence of alien craft, but 701 cases were left 'unidentified'.

Background

Soon after the 1947 'flying saucer' wave the US Air Force began collecting reports of unidentified objects, first under Project Sign (1948) and Project Grudge (1949). The effort was renamed Project Blue Book in 1952, based at Wright-Patterson Air Force Base in Ohio. Its job was to decide whether the objects threatened national security and whether they could be explained.

Blue Book was led for many years by Captain Edward Ruppelt, who coined the term 'unidentified flying object', and employed astronomer J. Allen Hynek as scientific consultant. Hynek began as a skeptic, but in later years pushed for more serious study. The project ended in December 1969 after a University of Colorado study, the Condon Report, recommended no further investigation.

What the record shows

• The Air Force's own fact sheet says that 12,618 reports were received and 701 remained unidentified.
• The records were later transferred to the National Archives and are public, with personal details redacted.
• The Robertson Panel's 1953 report was declassified; it recommended a public education program to reduce interest in UFOs.
• The Condon Report concluded that further extensive study of UFOs was unlikely to advance science.

Timeline

• 1948 Project Sign begins collecting reports.
• 1952 Project Blue Book is established; a big wave of sightings occurs over Washington, D.C. in July.
• Jan 1953 A CIA-convened panel (the Robertson Panel) recommends playing down UFO reports to avoid overloading intelligence channels.
• 1966 The 'swamp gas' explanation for a Michigan sighting is widely mocked.
• 1968 The Condon Report finds nothing to justify further study.
• 17 Dec 1969 The Air Force closes Project Blue Book.

Checking the claims

The claim: the Air Force hid the truth about UFOs. What the documents show is more mixed. The files confirm that the Air Force took reports seriously and also that it tried to downplay public interest, especially after the Robertson Panel. Many reports were explained as aircraft, balloons, stars, planets or hoaxes.

The 701 'unidentified' cases are the part of the record that keeps interest alive. In the Air Force's categories, 'unidentified' generally meant the information was too poor to reach a conclusion. It did not mean the object was extraterrestrial, and the project's own conclusions did not say so.

Claimed, but not shown

Blue Book found no evidence that unidentified objects were extraterrestrial craft or a threat. Claims that more secret projects ran in parallel are not confirmed by the public files.

Verdict

Sources

• US Air Force, Fact Sheet: Unidentified Flying Objects and Air Force Project Blue Book
• Project Blue Book files, National Archives
• Edward U. Condon (ed.), Scientific Study of Unidentified Flying Objects (1968)
• Robertson Panel report (1953), declassified

Connected files (red threads)

• Roswell — The Air Force's later reports on Roswell came out of the same debate
• UAP and "The Age of Disclosure" — Modern UAP studies repeat the same questions
• The 1947 flying disc wave in the FBI file — The wave of reports that started it
• Majestic 12: the forged documents — Forged documents claim a secret group above Blue Book
• Project Stargate: the CIA's psychic spies — Both were government projects that tried to investigate the unexplained
• The Rendlesham Forest incident — Official UFO investigation had ended, but reporting continued
• AARO's historical report on UFO claims — AARO's review starts from the Air Force era
• The CIA's role in the study of UFOs — The Air Force project the CIA history refers to

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