From 1952 to 1969, the United States Air Force conducted one of the most extensive UFO investigations in history — Project Blue Book.
Based at Wright-Patterson Air Force Base in Ohio, it was the successor to earlier efforts, Project Sign (1948) and Project Grudge (1949).
Its mission: determine whether UFOs posed a national security threat and assess if any were of extraterrestrial origin.
The Origins: From Project Sign to Blue Book
The first wave of post-war UFO sightings, including the 1947 Kenneth Arnold encounter and the Roswell incident,
forced the U.S. government to take the phenomenon seriously.
Project Sign initially concluded some UFOs might be “interplanetary,” but this conclusion was rejected by the Air Force in favor of a “psychological or misidentification” explanation.
By 1952, the sightings were too many to ignore — leading to the formation of Project Blue Book.
Mass Sightings and Military Alarm
The summer of 1952 brought hundreds of reports, including radar-visual UFOs over Washington D.C. that scrambled fighter jets and made national headlines.
These “Washington Flap” events led the CIA and Air Force to hold the Robertson Panel in 1953, recommending public debunking to reduce UFO hysteria.
Key Cases Investigated by Blue Book
- The Mantell Incident (1948) – A pilot died while chasing a bright object; official cause listed as Venus or a Skyhook balloon.
- The Lubbock Lights (1951) – Formation of glowing objects photographed over Texas; cause never identified.
- The Washington UFOs (1952) – Radar and pilot sightings over the U.S. capital; “temperature inversion” cited as explanation.
- The Lonnie Zamora Case (1964) – Police officer witnessed an egg-shaped craft in Socorro, New Mexico; considered one of Blue Book’s most credible cases.
Dr. J. Allen Hynek: From Skeptic to Believer
Dr. J. Allen Hynek, the scientific consultant for Project Blue Book, initially dismissed most UFO reports as explainable phenomena.
However, after years of fieldwork, Hynek admitted that around 5% of cases remained truly unexplained.
He later founded the Center for UFO Studies (CUFOS) and coined the term “Close Encounters.”
What Project Blue Book Actually Found
By the time it ended in 1969, Project Blue Book had analyzed 12,618 reports.
According to official Air Force records:
- 701 cases (5.6%) remained “unidentified.”
- No evidence of extraterrestrial craft or technology was officially found.
- Most sightings were attributed to stars, planets, weather balloons, or aircraft.
However, declassified memos show internal Air Force concern over radar-visual confirmations and multiple-witness cases that defied known physics.
The project’s conclusion that UFOs posed no threat — effectively ended all public U.S. military UFO research until the 2000s.
The Legacy of Project Blue Book
Decades later, the declassification of 129,000 pages of Blue Book files reignited interest in its findings.
Modern Pentagon UAP investigations, such as the AARO and UAP Task Force, have cited Blue Book as their historical foundation.
It remains the most comprehensive government UFO study ever conducted — and a cornerstone of official UAP history.
Verified Sources
- U.S. National Archives – Project Blue Book Files
- FBI Vault – Project Blue Book
- NSA – Unidentified Flying Objects and Air Force Project Blue Book
- U.S. Air Force – Unidentified Flying Objects and Air Force Project Blue Book
- Fold3 – US Project Blue Book UFO Investigations, 1947-1969
Project Blue Book officially ended in December 1969, but its shadow continues.
The Air Force publicly closed the case, yet 701 unexplained encounters remain on record.
These reports — documented, verified and unsolved, mark the moment when the U.S. government’s quest to understand UFOs went from secrecy to silence.