- Date:
- March 1952 - December 17, 1969
- Areas Of Involvement:
- unidentified flying object
- On the Web:
- National Archives - Project BLUE BOOK - Unidentified Flying Objects (Nov. 01, 2026)
Project Blue Book
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What was Project Blue Book?
Project Blue Book was a US Air Force program that ran from 1952 to 1969, created to investigate unidentified flying object (UFO) sightings. Headquartered at Wright-Patterson Air Force Base in Dayton, Ohio, it was the longest-running of the official inquiries into UFOs.
Over its 17 years, Project Blue Book documented over 12,000 sightings, categorizing them as "identified" or "unidentified." The "identified" sightings were linked to known astronomical, atmospheric, or human-made phenomena. Approximately 6% remained "unidentified" due to insufficient information. The project aimed to apply a methodical approach to the reports it received.
The project concluded that no UFO sightings posed a threat to national security, demonstrated advanced technology, or were of extraterrestrial origin.
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Why was Project Blue Book started by the United States Air Force?
Project Blue Book, which ran from 1952 to 1969, was the United States Air Force's longest-running program that investigated UFO sightings. It was the successor to Project Sign and Project Grudge.
The program aimed to determine if UFO sightings were extraterrestrial in origin or potential threats to national security, especially from the Soviet Union. Although the project documented 12,618 sightings, 701 remained unidentified when the program ended. The program concluded that UFO sightings posed no threat to national security, showed no evidence of technology unknown to humankind, and had no proof of extraterrestrial origin.
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What did Project Blue Book investigate?
Project Blue Book, running from 1952 to 1969, was the United States Air Force's longest-running program dedicated to investigating UFO sightings. The project recorded 12,618 sightings, of which 701 remained unidentified.
Most sightings had ordinary explanations such as natural phenomena, human error, hoaxes, or misidentified aircraft. In 2014, the CIA declassified documents revealing that over half of UFO reports from the late 1950s and most of the 1960s were U-2 and OXCART spy plane flights.
The project concluded that no UFO sightings posed a threat to national security, showed advanced technology unknown to humankind, or were of extraterrestrial origin.
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How did Project Blue Book collect and study reports?
Project Blue Book, running from 1952 to 1969, was the United States Air Force's longest-running program investigating UFO sightings. The project collected reports from the public, military, and government, recording 12,618 sightings, 701 of which remained unidentified when the program ended.
Aiming for a methodical approach, administrators created a questionnaire to standardize the documentation of what they recognized to be a subjective experience. Most sightings were attributed to earthly explanations such as natural phenomena, human error, hoaxes, or misidentified aircraft.
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What were some of the findings or conclusions of Project Blue Book?
Project Blue Book, which ran from 1952 to 1969, was the longest-running U.S. Air Force program that investigated UFO sightings. The project recorded 12,618 sightings, 701 of which remained unidentified when the program ended.
Key findings and conclusions:
- Most sightings had ordinary explanations, such as natural phenomena, human error, hoaxes, or misidentified aircraft.
- No UFO sightings ever posed a threat to national security, showed evidence of unknown technology, or proved extraterrestrial origin.
- A report from the University of Colorado led to the conclusion that there was no advantage for the Air Force to continue studying UFO sightings.
- The Robertson Panel concluded that 90 percent of sightings could be attributed to astronomical, meteorological, or earthly objects and that there was no security threat or evidence to support extraterrestrial hypotheses.
- The Condon Report concluded that there was no evidence of anything other than commonplace phenomena and that UFOs did not warrant further investigation.
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Why did Project Blue Book end, and what happened to the information it gathered?
Project Blue Book, the United States Air Force program investigating unidentified flying objects (UFOs), ended on December 17, 1969, after a report from the University of Colorado concluded that UFO sightings posed no threat to national security, revealed no advanced technology, and had no extraterrestrial origins. The report suggested that further study of UFOs would be unproductive for the Air Force.
The information gathered during Project Blue Book, including records of 12,618 sightings, is available to the public. These declassified and redacted records have been housed at the National Archives Building in Washington, D.C., since 1976.
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Project Blue Book, code name for the United Statesā longest-running Air Force program dedicated to investigating sightings of UFOs (unidentified flying objects), which ran from 1952 to 1969. The program generated controversy because of its subject matter and the secrecy surrounding its operation.
Project Blue Book was the successor of two similar programs. The first was Project Sign, a classified program that tried to explain a number of military-reported UFO sightings and determine whether they were extraterrestrial in origin, while also considering potential threats to national security, especially those related to possible espionage by the Soviet Union. Project Sign lasted from December 1947 to February 1949 and investigated 243 sightings. It was scaled down to become Project Grudge, which persisted for six more months and collected 244 additional sighting reports. Project Blue Book was launched in March 1952, and it began accepting reports of sightings from the public, as well as the military and government. The three projects are often collectively considered Project Blue Book.
Project Blue Book was headquartered at Wright Air Force Base (now Wright-Patterson Air Force Base), near Dayton, Ohio. From 1947 to 1969, 12,618 sightings were recorded; of these, 701 remained labeled āunidentifiedā when the program concluded. Records from the project concerning reports of individual or group sightings totaled tens of thousands of pages, with additional pages of project files, police reports, newspaper clippings, administrative documents, footage, and photographs. The declassified and redacted records have been housed at the National Archives Building in Washington, D.C., since 1976 and are available to the public. No physical evidence of extraterrestrial origin was collected during the course of the project.
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Project Blue Book was named for the blue exam booklets frequently used in American college testing, indicating the project administratorsā stated intent to apply a scholarly and methodical approach to the program. They created a questionnaire for sighting reports, aiming to standardize documentation of a highly subjective experience.
The majority of sightings reported were assigned ordinary earthly explanations: natural phenomena, human error, hoaxes, and, the largest category, mistaken identification of military or civilian aircraft. In 2014 the Central Intelligence Agency (CIA) declassified a history of the U-2 spy plane program, which revealed that Blue Book investigators regularly contacted the CIA and found that āU-2 and later OXCART [the Lockheed A-12 spy plane] flights accounted for more than one-half of all UFO reports during the late 1950s and most of the 1960s.ā The sightings that remain unidentified are fairly evenly divided among each year of the program and its precursorsā existence, except for 1952, which has 303 unexplained sightings. Many of the reports from this year concern a group of sightings over Washington, D.C., that July.
The comparatively large number of unexplained reports in 1952 prompted further discussion. (Most other years typically had about a dozen unexplained sightings.) According to a CIA committee, the Robertson panel, which met in 1953 and whose report was declassified in 1975, the ultimate goal of government investigations of UFOs was to debunk all sightings in a way that would decrease public interest in UFOs. Some individuals involved in the project, including American astronomer J. Allen Hynek, who served as lead scientist on the project for its entire span, later alleged that they were discouraged from pursuing extraterrestrial explanations for reported sightings. (Hynek in particular was privately critical of Project Blue Bookās lack of rigor and emphasis on debunking.)
Project Blue Book was terminated on December 17, 1969, after a two-year report commissioned from the University of Colorado concluded, after reviewing the projectās records and findings, that no UFO sightings had ever represented a threat to national security, shown definitive evidence of technology unknown to humankind, or been proved to be of extraterrestrial origin. The report indicated that there would be no great advantages for the Air Force to continue to study UFO sightings.
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A more recent government-funded study of UFOs launched in 2020 with the advent of the Unidentified Aerial Phenomena Task Force, established by the Department of Defense, under the jurisdiction of the U.S. Navy.