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Project Blue Book

A US Air Force programme that investigated UFO sightings from 1952 to 1969, constituting the longest-running official American government inquiry into unidentified aerial phenomena.

1952-03 to 1969-12-17 · Wright-Patterson Air Force Base, Dayton, Ohio · US Air Force · Terminated · UFO investigation programme

Project Blue Book was a US Air Force programme established to investigate reports of unidentified flying objects. It was formally initiated in 1952 when the USAF Director of Intelligence created the programme to study UFO phenomena,1 with USAF Director of Intelligence Major General Charles P. Cabell having formally stood up the project in March of that year.2 The programme was based at Wright Patterson Air Force Base near Dayton, Ohio,3 and ran continuously from March 1952 until December 1969.4 It was preceded by earlier US Air Force studies that had begun investigating claimed UFO sightings as early as 1947,5 including Project GRUDGE Original. Project Blue Book organised its accumulated cases into three categories: identified, insufficient data, and unidentified.6 Of the 12,618 sightings in its holdings, 701 were categorised as unidentified and were never resolved.7

The programme’s scientific work was led by J. Allen Hynek, who served as its lead scientific investigator throughout its operational life.8 On the administrative side, Project Blue Book was directed successively by Edward Ruppelt, Captain Charles Hardin, Captain George T. Gregory, Lieutenant Colonel Roger J. Friend, and Lieutenant Colonel Hector Quintanilla.9 Edward Ruppelt, the programme’s first director, later noted that the inability to collect a UFO’s altitude, size, and speed was a recurring and significant obstacle to resolving cases.10 In 1953, the US Air Command created the 4602d Air Intelligence Service Squadron to confidentially vet all UAP reports before they were forwarded to Project Blue Book, with the unit tasked with culling sightings that raised national security concerns before they entered the official record.11

Project Blue Book’s formal conclusions stated that no UFO it investigated demonstrated any indication of a threat to national security12 and that no sightings provided evidence of technological developments or principles beyond the range of then-current scientific knowledge.13 However, both J. Allen Hynek and Edward Ruppelt later made statements suggesting a more complicated institutional picture. J. Allen Hynek said the Air Force expected him to perform the role of debunker,14 while Edward Ruppelt wrote that he had been expected to explain away every report and that the USAF sought press coverage aligned with its official position.15 J. Allen Hynek separately concluded that the Robertson Panel of 1953 had had debunking as its primary purpose.16 Harry Turner, whose account was reported second-hand, asserted that in 1953 the Air Force Office of Special Investigations (AFOSI) persuaded the USAF to use Project Blue Book as a vehicle for publicly debunking UFOs whilst the US secretly launched a crash programme into anti-gravity power.17 A report subsequently prepared by Australia’s Department of Defence in the 1970s similarly characterised Project Blue Book’s strategy as erecting “a façade of ridicule” to allay public alarm, reduce Soviet exploitation of UAP mass sightings, and act as cover for a real US development programme.31

One of the programme’s most prominent controversies arose from the Michigan UAP Sightings 1966. In March 1966, following reports of strange craft over several days in Michigan neighbourhoods, Project Blue Book reviewed the matter at the insistence of Michigan congressman Gerald Ford and announced that witnesses had seen swamp gas.18 The Ford Presidential Library has since released at least fifteen documents related to this finding, which Gerald Ford remained sceptical of for the rest of his life.19 A 1964 USAF Ad Hoc Review of Project Blue Book, chaired by Dr Brian O’Brien and including prominent astronomer Carl Sagan, also formed part of the institutional review history of the programme.20 Christopher K. Mellon has written that the Condon Report ultimately provided the Air Force with the justification it sought to close the project.21

Project Blue Book was terminated on 1969-12-17, when Seamans Jr., Robert C., as Secretary of the Air Force, announced its end, stating it “no longer can be justified either on the ground of national security or in the interest of science."22,23 J. Allen Hynek lamented the closure, observing that science had effectively declared that thousands of people who had reported strange sightings could all be discounted as deluded, hoaxers, or mentally unbalanced.24 The All-Domain Anomaly Resolution Office (AARO) has since partnered with the US National Archives to examine Project Blue Book records spanning 1947 to 1969, a corpus amounting to 7,252 files holding 65,778 digital records.25 AARO has assessed that there was approximately a 40-year gap in formal UAP investigation programmes between the termination of Project Blue Book in 1969 and the standup of the Advanced Aerospace Threat Identification Program (AATIP) in 2009.26 At a May 2022 UAP congressional hearing, the Pentagon’s intelligence chief Ronald Moultrie, when asked about research into UAP programmes, stated: “Other than AATIP and Blue Book, no."32

Daniel Sheehan has made notable claims regarding classified materials within the Project Blue Book archive. In late spring 1977, Sheehan states he was granted access to view classified Project Blue Book microfiche documents held at the Library of Congress.27 He states that among those materials he found a photograph of a crashed, full-scale saucer-shaped craft with a dome, which had ploughed a trench across a snow-covered field and was stuck at a 45-degree angle in a snowbank, with US Air Force personnel visible around it.28 Sheehan further states that one of the photographs showed symbols etched into the side of the craft just below the dome, which he traced onto the cardboard backing of a legal notepad he had brought into the room.29 These claims, which relate directly to the Daniel Sheehan Blue Book Viewing and have not been independently verified, remain among the more contested assertions in the wider UAP discourse.

  1. The USAF Director of Intelligence initiated Project Blue Book in 1952 to investigate UFOs.
    “In 1952, the U.S. Air Force Director of Intelligence initiated PROJECT BLUE BOOK to investigate unidentified flying objects.”
    DODIG-2023-109 Unclassified Summary: Evaluation of DoD Actions Regarding UAP page 1, Historical Background
  2. Project Blue Book was established by USAF Director of Intelligence Major General Charles P. Cabell in March 1952.
    “USAF Director of Intelligence, Major General Charles P. Cabell, established Project BLUE BOOK to study UFO phenomena.”
    AARO Historical Record Report Volume I: U.S. Government Involvement with UAP page 19, Project BLUE BOOK section
  3. Project Blue Book was based at Wright-Patterson Air Force Base near Dayton, Ohio.
    “Based at Wright-Patterson Air Force Base near Dayton, Ohio, Project BLUE BOOK was the longest running UFO/UAP investigation.”
    AARO Historical Record Report Volume I: U.S. Government Involvement with UAP page 19, Project BLUE BOOK section
  4. Project Blue Book ran from March 1952 to December 1969.
    “Project BLUE BOOK (March 1952-December 1969)”
    AARO Historical Record Report Volume I: U.S. Government Involvement with UAP page 2, Table of Contents
  5. The US Air Force began a series of UFO studies in 1947, investigating more than 12,000 sightings before ending in 1969.
    “In 1947, the Air Force began a series of studies that investigated more than 12,000 claimed U.F.O. sightings before it was officially ended in 1969.”
    Glowing Auras and 'Black Money': The Pentagon's Mysterious U.F.O. Program (2017) paragraph 20
  6. Project Blue Book organised its cases into three categories: identified, insufficient data, and unidentified.
    “Project BLUE BOOK organized its cases into one of three categories: identified, insufficient data, and unidentified.”
    AARO Historical Record Report Volume I: U.S. Government Involvement with UAP page 19, Project BLUE BOOK section
  7. Of 12,618 sightings in Project Blue Book's holdings, 701 were categorised as unidentified and never solved.
    “Of the 12,618 sightings in Project BLUE BOOK's holdings, 701 were categorized as unidentified and never solved.”
    AARO Historical Record Report Volume I: U.S. Government Involvement with UAP page 19, Project BLUE BOOK Results
  8. J. Allen Hynek served as the lead scientific investigator for Project Blue Book.
    “J. Allen Hynek served as its lead scientific investigator.”
    AARO Historical Record Report Volume I: U.S. Government Involvement with UAP page 19, Project BLUE BOOK section
  9. Project Blue Book was led successively by Edward J. Ruppelt, Captain Charles Hardin, Captain George T. Gregory, Lieutenant Colonel Roger J. Friend, and Lieutenant Colonel Hector Quintanilla Jr.
    “It was led successively by Capt Edward J. Ruppelt (the former Director of the reorganized Project GRUDGE), Capt Charles Hardin, Capt George T. Gregory, Lieutenant Colonel (Lt Col) Roger J. Friend, and Lt Col Hector Quintanilla, Jr.”
    AARO Historical Record Report Volume I: U.S. Government Involvement with UAP page 19, Project BLUE BOOK section
  10. Edward Ruppelt noted the inability to collect a UFO's altitude, size, and speed was a recurring obstacle to resolving cases.
    “Capt Ruppelt, the first director of Project BLUE BOOK, noted that the inability to collect the UFO's altitude, size, and speed was a recurring and significant obstacle to resolving cases.”
    AARO Historical Record Report Volume I: U.S. Government Involvement with UAP Section VII, Commonalities: Insufficient Data and Information
  11. In 1953, the US Air Command created the 4602d Air Intelligence Service Squadron to vet UAP reports before they reached Project Blue Book, culling sightings with national security implications.
    “in 1953, the US Air Command had created the 4602d Air Intelligence Service Squadron (AISS) that confidentially vetted all UAP reports before they were sent to Blue Book, culling sightings that raised national security concerns.”
    Ross Coulthart UAP Book - Prologue, Chapter 1 & Chapter 2 Chapter 6, endnotes 9-10
  12. Project Blue Book determined that no UFO it investigated demonstrated any indication of a threat to national security.
    “No UFO reported, investigated, and evaluated by the USAF demonstrated any indication of a threat to national security.”
    AARO Historical Record Report Volume I: U.S. Government Involvement with UAP page 19, Project BLUE BOOK Results
  13. Project Blue Book found no evidence that UFO sightings represented technological developments beyond then-current scientific knowledge.
    “There was no evidence submitted to, or discovered by, the USAF that sightings represented technological developments or principles beyond the range of then-present day scientific knowledge.”
    AARO Historical Record Report Volume I: U.S. Government Involvement with UAP page 19, Project BLUE BOOK Results
  14. J. Allen Hynek said the Air Force expected him to perform the role of debunker.
    “J. Allen Hynek of Project BLUE BOOK, said that the USAF expected him to perform the role of debunker”
    AARO Historical Record Report Volume I: U.S. Government Involvement with UAP Section VII, Commonalities: Perceived Deception
  15. Edward Ruppelt wrote that he was expected to explain away every report and that the USAF sought press stories aligned with its position.
    “Capt Ruppelt, the first chief of BLUE BOOK, later wrote that he was expected to explain away every report and that the USAF sought to produce press stories in alignment with the USAF's position.”
    AARO Historical Record Report Volume I: U.S. Government Involvement with UAP Section VII, Commonalities: Perceived Deception
  16. J. Allen Hynek concluded that the Robertson Panel's primary role was to debunk all UAP sightings.
    “It became clear to Project Blue Book consultant Dr J. Allen Hynek that the Robertson Panel's primary role was to debunk all UAP sightings and to put control of investigations into the phenomenon back with the air force.”
    Ross Coulthart UAP Book - Prologue, Chapter 1 & Chapter 2 (2021)
  17. Harry Turner asserted that in 1953 the Air Force Office of Special Investigations persuaded the USAF to use Project Blue Book to publicly debunk UFOs while secretly launching a crash programme into anti-gravity power.
    “He asserted that in 1953 the US Air Force Office of Special Investigations persuaded the US Air Force to use the Project Blue Book investigation into UAPs as a 'means of publicly "debunking" UFOs' while at the same time the US was secretly launching a crash program into anti-gravity power.”
    Ross Coulthart UAP Book - Prologue, Chapter 1 & Chapter 2 Chapter 6, paragraph 2
  18. In March 1966, Project Blue Book reviewed Michigan UAP sightings at the insistence of congressman Gerald Ford and announced witnesses had seen swamp gas.
    “March 1966: Neighborhoods in Michigan were terrorized over several days by strange craft … At the insistence of a leading Michigan congressman named Gerald Ford, Dr. Hynek's Project Blue Book reviewed the matter thoroughly, and unfortunately announced that the witnesses had seen… swamp gas.”
    Imminent: Inside the Pentagon's Hunt for UFOs — Chapter 2 (image only) Chapter 4, March 1966 section
  19. The Ford Presidential Library has released at least fifteen documents related to Project Blue Book's 'swamp gas' finding from the 1966 Michigan sightings.
    “The Ford Presidential Library has since released at least fifteen documents related to the notorious Blue Book 'swamp gas' finding, of which Ford remained forever skeptical.”
    Imminent: Inside the Pentagon's Hunt for UFOs — Chapter 2 (image only) Chapter 23, paragraph 31
  20. The 1964 USAF Ad Hoc Review of Project Blue Book was chaired by Dr Brian O'Brien and included Carl Sagan.
    “Dr. Brian O'Brien, a member of the USAF Scientific Advisory Board, chaired the USAF Ad Hoc Review of Project BLUE BOOK. The committee included Carl Sagan, a prominent astronomer from Cornell University.”
    AARO Historical Record Report Volume I: U.S. Government Involvement with UAP page 20, O'Brien Committee section
  21. The Condon Report provided the Air Force the excuse it sought to close Project Blue Book.
    “Dr. Condon's report provided the Air Force the excuse it sought to close Project Blue Book, its controversial UFO investigation.”
    Imminent: Inside the Pentagon's Hunt for UFOs — Chapter 2 (image only) Foreword, paragraph 4
  22. Secretary of the Air Force Robert C. Seamans Jr. announced Project Blue Book's termination on 1969-12-17.
    “Secretary of the Air Force Robert C. Seamans, Jr. announced Project BLUE BOOK's termination on December 17, 1969.”
    AARO Historical Record Report Volume I: U.S. Government Involvement with UAP page 19, Project BLUE BOOK section
  23. Seamans stated Blue Book 'no longer can be justified either on the ground of national security or in the interest of science.'
    “Robert C. Seamans Jr., the secretary of the Air Force at the time, said in a memorandum announcing the end of Project Blue Book that it 'no longer can be justified either on the ground of national security or in the interest of science.'”
    Glowing Auras and 'Black Money': The Pentagon's Mysterious U.F.O. Program (2017) paragraph 21
  24. J. Allen Hynek lamented the closure of Project Blue Book, saying science had spoken and thousands of people could all be discounted as deluded, hoaxers, or mentally unbalanced.
    “Blue Book consultant Dr J. Allen Hynek lamented, 'this was indeed the coup de grace to the UFO era. Science had spoken. UFOs didn't exist, and the thousands of people who had reported strange sightings . . . could all be discounted as deluded, hoaxers, or mentally unbalanced'.”
    Ross Coulthart UAP Book - Prologue, Chapter 1 & Chapter 2 paragraph 18
  25. AARO partnered with the US National Archives to examine Project Blue Book records spanning 1947 to 1969, amounting to 7,252 files and 65,778 digital records.
    “AARO partnered with the U.S. National Archives to examine the records from the USAF's Project BLUE BOOK, which spanned from 1947 to 1969. This research presented a significant challenge because of the volume of the documentation amounted to 7,252 files holding a total of 65,778 digital records.”
    AARO Historical Record Report Volume I: U.S. Government Involvement with UAP page 19, Project BLUE BOOK section
  26. There was approximately a 40-year gap in UAP investigation programmes between the termination of Project Blue Book in 1969 and the standup of AAWSAP and AATIP in 2009.
    “Prior to AAWSAP/AATIP there was about a 40 year gap in UAP investigation programs since the termination of Project BLUE BOOK in 1969.”
    AARO Historical Record Report Volume I: U.S. Government Involvement with UAP page 10, Section II Executive Summary
  27. Daniel Sheehan arrived at the Library of Congress in late spring 1977 to view classified Project Blue Book microfiche documents.
    “on a Saturday morning in Washington DC in the late spring of 1977, an eager Daniel Sheehan arrived at the still-uncompleted Madison wing of the Library of Congress for a cloak-and-dagger rendezvous with the classified Project Blue Book documents.”
    Ross Coulthart UAP Book - Prologue, Chapter 1 & Chapter 2 Chapter 6, paragraph 16
  28. Sheehan states he found in the classified Blue Book microfiche a photograph of a crashed saucer with US Air Force personnel around it.
    “what he saw in the multiple images was a full-scale classic saucer with a dome. The craft he saw had crashed in a field and was covered with snow. He describes how the saucer had ploughed a huge trench across the field and it was stuck at a 45-degree angle in what looked like a snowbank. There were soldiers dressed in US Air Force parkas and weather gear”
    Ross Coulthart UAP Book - Prologue, Chapter 1 & Chapter 2 Chapter 6, paragraph 18
  29. Sheehan states one photograph showed symbols etched into the side of the craft, which he traced onto a legal notepad.
    “One of the photographs showed symbols, not any language he recognised, etched into the side of the craft just below the dome. At that point Sheehan remembered the yellow legal notepad he had snuck into the room, and he traced the odd symbols onto the inside cardboard backing of his notepad.”
    Ross Coulthart UAP Book - Prologue, Chapter 1 & Chapter 2 Chapter 6, paragraph 19
  30. An Australian Department of Defence report from the 1970s described Project Blue Book's strategy as erecting 'a façade of ridicule' as cover for a real US programme.
    “A report prepared by Australia's Department of Defense in the 1970s summed up the Blue Book strategy as follows: 'By erecting a façade of ridicule, the US hoped to allay public alarm, reduce the possibility of the Soviet[s] taking advantage of UAP mass sightings for either psychological or actual warfare purposes, and act as a cover for the real US program of developing vehicles that emulate UAP performances.'”
    Imminent: Inside the Pentagon's Hunt for UFOs — Chapter 2 (image only) Chapter 4, Australia DoD report section
  31. At the May 2022 UAP hearing, Pentagon intelligence chief Ronald Moultrie stated that AATIP and Blue Book were the only UAP programmes he was aware of.
    “when asked about any research into other UAP programs, the head of the Pentagon's intelligence efforts, Ronald Moultrue, said, 'Other than AATIP and Blue Book, no.'”
    Imminent: Inside the Pentagon's Hunt for UFOs — Chapter 2 (image only) Chapter 23, paragraph 60

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