According to researcher Chris Ramsay, the Roswell crash and the sighting by Kenneth Arnold, followed by the Aztec crash, prompted government and military interest in UFOs that led to the formation of Project Grudge, which later became Project Blue Book.1 Project Blue Book was the code name for the group that studied Unidentified Anomalous Phenomena (UAP) for the United States Air Force (USAF) from 1952 to 1969.2 It was established in 1952, when the USAF Director of Intelligence initiated the project to investigate Unidentified Flying Objects (UFO),3 reorganised from the preceding Project GRUDGE4 and credited to USAF Director of Intelligence Major General Charles P. Cabell.5 Based at Wright-Patterson Air Force Base near Dayton, Ohio,6 it became the longest-running UFO/UAP investigation,7 with a brief to determine whether UFOs were a threat to national security and to scientifically analyse the data gathered.8
The project was led successively by Capt Edward J. Ruppelt, former director of the reorganised Project GRUDGE (Reestablishment),9 then by Capt Charles Hardin, Capt George T. Gregory, Lt Col Roger J. Friend, and Lt Col Hector Quintanilla, Jr.10 Edward Ruppelt was Blue Book’s first director.11 J. Allen Hynek, a civilian scientist, served as the project’s consultant12 and lead scientific investigator.13 Hynek later said the USAF expected him to perform the role of debunker,14 and Ruppelt himself wrote that he was expected to explain away every report, with the Air Force seeking press stories that aligned with its position.15 In March 1966, Jacques Vallée alerted Hynek to a wave of sightings in Michigan, and Hynek in turn telephoned Blue Book in Dayton, Ohio to propose an investigation.16 At the insistence of Michigan congressman Gerald Ford, Hynek’s investigation into the 1966 Michigan swamp gas UAP sightings announced that witnesses had seen swamp gas.17 According to Luis Elizondo, Ford himself remained sceptical of that finding.18
Between 1952 and 1969, USAF personnel investigated more than 12,000 reported UFO sightings,19 12,618 in total.20 According to a US government historical review, 701 of these were categorised as unidentified and never solved,21 with cases sorted into three categories: identified, insufficient data, and unidentified.22 The project dismissed the vast majority of reports as misidentifications with prosaic explanations.23 The United States Navy (USN) pursued a parallel channel: Dan Kimball ordered his own naval intelligence reports on UAP, independent of the Air Force’s project.24 According to Harry Turner, the US Air Force Office of Special Investigations persuaded the Air Force in 1953 to use the project as a means of publicly debunking UFOs.25 The book In Plain Sight describes the project as having often been derided for its perceived over-zealousness in aggressively debunking almost all UAP sightings.26 David Fravor has said the project worked to debunk and disprove sightings, at times to the point of discrediting witnesses,27 and has described it as having represented an active disinformation campaign to deny the existence of UAP.28 The US government maintained a serious background interest in UAP while the project publicly explained sightings away as prosaic causes such as ball lightning and swamp gas.29 By 1967, James MacDonald found that the project, by then about fourteen years old,30 consisted of only three people: a major, a sergeant and a secretary,31 and considered the regard in which it was held unjustified, describing its investigations as superficial and conducted by persons of extremely low scientific competence.32
The 1953 Robertson Panel, described as the impetus for Project Blue Book, recommended a media campaign to manage public perception of the phenomenon.33 The Condon Report subsequently gave the USAF the justification it had sought to close the project,34 and after the report drew criticism from scientists including Hynek, a National Academy of Sciences panel was tasked in late 1968 with examining its rigour, methodology and conclusions.35 Secretary of the Air Force Robert C. Seamans Jr. announced Project Blue Book’s termination on 1969-12-17,36 stating in his memorandum that it “no longer can be justified either on the ground of national security or in the interest of science."37 The Air Force closed the project in 1970, publicly ending official UFO investigations without having found an explanation for many incidents,38 by which point it operated largely as a public-relations effort to investigate and discredit UAP reports.39
The All-domain Anomaly Resolution Office (AARO) partnered with the US National Archives to examine Blue Book’s records, which span 1947 to 1969,40 amounting to 7,252 files holding 65,778 digital records,41 the vast majority of them USAF documentation.42 AARO’s review found a spike in reported sightings from 1952 to 1957 and another spike in 1960.43 Roughly forty years passed between Blue Book’s termination and the Advanced Aerospace Weapon System Applications Program (AAWSAP) and Advanced Aerospace Threat Identification Program (AATIP),44 whose research, according to the AARO historical report, included reviewing older Blue Book cases.45 At a May 2022 congressional hearing, Ronald Moultrie, then head of the Pentagon’s intelligence efforts, testified under oath that AATIP and Project Blue Book were the only prior UAP research programmes of which he was aware.46
In 1977, attorney Daniel Sheehan viewed Blue Book’s classified holdings.47 Aware of allegations that the most important UAP reports had been withheld from the project, he had told Marcia Smith of the Library of Congress that he wanted to see them,48 recalling that he told her “you never get if you don’t ask."49 A week later, Smith called him with news that permission had been granted.50 On a Saturday morning in the late spring of 1977, Sheehan arrived at the then-uncompleted Madison wing of the Library of Congress in D.C. Washington to view the classified documents, an occasion later recounted as the 1977 Daniel Sheehan Library of Congress Blue Book viewing,51 held in a room set up with foldout tables, a microfiche viewer and shoebox-sized boxes of microfiche canisters.52 He recalls being told he could not take notes,53 and says the images showed a full-scale classic saucer with a dome54 that had crashed in a snow-covered field.55 Sheehan says he remains convinced the images were photographic evidence of an extra-terrestrial spacecraft.56 He recalls that neither of the two 1977 classified reports prepared for President Carter mentioned the images he says he saw,57 and his account has gone unchallenged by any official,58 with no one in government or the military ever seeking to respond to, explain or acknowledge his discovery or a reported incursion at the sensitive military facility.59