Project Blue Book: the Air Force’s UFO study

About Project Blue Book

The full story, section by section

The story of Project Blue Book in 8 parts. Tap any part to read it in full.

1. PredecessorsPublic Air Force UFO studies began with Project Sign at the end of 1947.Read this part → Illustration drawn for this site — not a photograph.
2. LeadershipBy late 1951, senior generals including Charles Cabell were dissatisfied with UFO investigations.Read this part → Captain Edward J. Ruppelt (left), Blue Book's first head. · Photo: Unknown authorUnknown author, Public domain, Wikimedia Commons
3. The 1952 wave and the Robertson PanelBlue Book's busiest year was 1952.Read this part → Illustration drawn for this site — not a photograph.
4. Air Force Regulation 200-2After the panel, the Air Force issued Regulation 200-2.Read this part → Illustration drawn for this site — not a photograph.
5. Special Report No. 14Ruppelt commissioned the Battelle Memorial Institute to design the reporting form and analyse cases.Read this part → Illustration drawn for this site — not a photograph.
6. The 1966 hearing and the Condon CommitteeA wave of sightings in 1965–1966 brought sharp criticism.Read this part → J. Allen Hynek (left), Blue Book's scientific consultant, with Jacques Vallée. · Photo: United States Government, Public domain, Wikimedia Commons
7. ClosureOn 17 December 1969 Air Force Secretary Robert Seamans announced that Blue Book would close.Read this part → Illustration drawn for this site — not a photograph.
8. Assessment and legacyThe Air Force's position is that Blue Book found no threat to national security, no technology beyond known science and no evidence of extraterrestrial vehicles.Read this part → Illustration drawn for this site — not a photograph.

Read the full Project Blue Book article →

Key people

The people at the centre of the story — witnesses, investigators, officials and sceptics:

• Edward RuppeltEdward James Ruppelt was a United States Air Force officer and aeronautical engineer who led the military's UFO investigations from 1951 to 1953. During this time, he revived Project Grudge, transfor…
• J. Allen HynekJ. Allen Hynek was an American astronomer and professor who served for over two decades as the U.S.
• Nathan TwiningNathan Farragut Twining was a United States Air Force general who served as Chief of Staff of the Air Force and as Chairman of the Joint Chiefs of Staff. Over a 45-year career spanning major military…
• Kenneth ArnoldKenneth Arnold was an American aviator and businessman who reported seeing nine shiny, fast-moving objects near Mount Rainier, Washington, on June 24, 1947. His widely publicized account inspired nat…
• Hector QuintanillaHector Quintanilla Jr. was a U.S.
• Michael ShellenbergerMichael Shellenberger is an American writer and political activist known for his ecomodernist views, books on various public issues, and unsuccessful runs for governor of California. In 2024, he publ…
• Harold BrownHarold Brown was an American nuclear physicist and government official who served as Secretary of Defense and Secretary of the Air Force. In 1966, he represented the Air Force at the first congressio…
• Edward CondonEdward Uhler Condon was an American nuclear physicist and an early figure in quantum mechanics who directed the National Bureau of Standards and later led the University of Colorado UFO Project. Duri…
• Robert LowRobert Low served as project coordinator of the University of Colorado UFO Project, known as the Condon Committee, from 1966 to 1968. He wrote a 1966 memo suggesting the study present an appearance o…
• Brad SparksBrad Sparks is an American UFO researcher who is best known for compiling and revising a comprehensive database of Project Blue Book unknown cases. His work includes detailed studies of historical UF…
• Jacques ValléeJacques Vallée is a French computer scientist, internet pioneer, venture capitalist, author, astronomer, and ufologist born in 1939. He began his career as an astronomer, co-developing NASA's first d…
• Leonard StringfieldLeonard Stringfield was an American ufologist from Cincinnati, Ohio, who directed the civilian UFO group CRIFO in the 1950s and later worked with organizations like NICAP and MUFON. He is best known …

Related cases & events

Events and sightings linked to Project Blue Book:

🗓️ Event · 17 min readCondon ReportThe Condon Report was a 1968 scientific study of unidentified flying objects conducted by the University of Colorado UFO Project and directed by physicist Edward U. Condon. Funded by the U.🗓️ Event · 6 min readBlue Book Special Report No. 14Blue Book Special Report No. 14 was a massive statistical study of 3,201 UFO reports commissioned by the U.S.🗓️ Event · 8 min readTwining memo (1947)The Twining memo is a 1947 letter written by Lieutenant General Nathan F. Twining stating that reported flying discs were real objects that warranted formal investigation. The document led to the creation of the United States military's first official UFO stu…🛸 Case · 10 min readLubbock LightsThe Lubbock Lights were formations of soft, glowing bluish-green lights seen by multiple witnesses over Lubbock, Texas, and surrounding areas between August and September 1951. The sightings were famously observed by a group of college professors and photogra…🛸 Case · 14 min readWashington, D.C. UFO incidentThe 1952 Washington, D.C., UFO incident was a series of radar and visual sightings of unidentified objects over the U.🗓️ Event · 6 min readHynek's The UFO ExperienceThe 1972 book The UFO Experience: A Scientific Inquiry was written by astronomer and former Air Force consultant J. Allen Hynek. The text critiques Project Blue Book and calls for serious scientific investigation into unidentified flying objects.🗓️ Event · 9 min readRuppelt held back before the Robertson PanelThe article discusses a claim by UFO historian Brad Sparks that on December 9, 1952, Colonel Donald L. Bower forbade Project Blue Book chief Edward Ruppelt from delivering certain UFO case reports to the CIA. According to Sparks, this order was part of an Air…🗓️ Event · 27 min readRobertson PanelThe Robertson Panel was a group of scientists assembled by the Central Intelligence Agency in Washington in January 1953 to review the U.S. Air Force's evidence on unidentified flying objects.🗓️ Event · 5 min readJANAP 146(C)JANAP 146(C) was a joint U.S. Army, Navy, and Air Force directive issued on March 10, 1954, that instructed military and civilian pilots, as well as U.

Programs, organizations & documents

The official programs, groups and papers involved:

🏢 Organization · 13 min readU.S. Air ForceThe United States Air Force is the air service branch of the U.S. armed forces that became an independent service in September 1947.🏛️ Program or study · 6 min readProject SignProject Sign was the United States Air Force's first official study of unidentified flying objects, active for most of 1948 at Wright Field in Ohio. The project investigated various UFO sightings and allegedly concluded in an unproven top-secret report that t…🏛️ Program or study · 6 min readProject GrudgeProject Grudge was the United States Air Force's UFO investigation program that ran from February 1949 to March 1952. The study operated primarily to explain sightings away, ease public anxiety, and conclude that UFOs posed no security threat, though about 23…📄 Document · 6 min readEstimate of the SituationThe Estimate of the Situation was a top-secret 1948 report by the staff of the U.S. Air Force's Project Sign at the Air Technical Intelligence Center.🏢 Organization · 10 min read4602d Air Intelligence Service SquadronThe 4602d Air Intelligence Service Squadron was a United States Air Force intelligence unit headquartered in Colorado Springs, Colorado. During the 1950s, its wartime responsibility was examining downed enemy aircraft and questioning captured airmen, while it…🏢 Organization · 7 min readBattelle Memorial InstituteThe Battelle Memorial Institute is a private, non-profit applied science and technology organization headquartered in Columbus, Ohio, that carries out contract research and manages government laboratories. Founded in 1929, the institute is notably known in UF…🏛️ Program or study · 6 min readProject StorkProject Stork was a 1953–1955 contract program between the Battelle Memorial Institute and the United States Air Force to scientifically study UFO sighting reports. The work involved creating standardized reporting forms, coding data onto IBM punched cards, a…🏢 Organization · 8 min readHouse Armed Services CommitteeThe House Armed Services Committee is a standing committee of the US House of Representatives responsible for funding and overseeing the Department of Defense, the armed forces, and much of the Department of Energy. Created by the Legislative Reorganization A…📄 Document · 6 min readBolender memoThe Bolender memo is a 1969 U.S. Air Force staff summary signed by Brigadier General Carroll H.

Books, films & documentaries

Where to read and watch more:

🎬 Book or film · 6 min readThe Report on Unidentified Flying ObjectsThe Report on Unidentified Flying Objects is a 1956 book by former U.S. Air Force captain Edward J.🎬 Book or film · 4 min readProject Blue Book (TV series)Project Blue Book is an American historical drama television series broadcast on History from January 2019 to March 2020. Created by David O'Leary, the show is loosely based on the U.S.

Related topics & places

Ideas, terms and places that come up in the story:

📍 Place · 19 min readWright-Patterson Air Force BaseWright-Patterson Air Force Base is a U.S. Air Force facility formed in Ohio in 1948 by merging Wright Field and Patterson Field.📖 Term · 17 min readUnidentified flying objectAn unidentified flying object, or UFO, is an unexplained phenomenon or object seen in the sky, with the modern craze originating in the United States in June 1947. While popular culture often equates UFOs with alien spacecraft, most investigations reveal them…📖 Term · 13 min readUnidentified anomalous phenomenaUnidentified anomalous phenomena (UAP) is the U.S. government's current term for unidentified objects or events in the air, space, or underwater.🧭 Topic overview · 30 min readSecrecy & cover-up (topic)This overview page covers official secrecy, classification, and cover-up claims regarding unidentified anomalous phenomena from 1947 to 2023. It outlines historical classified studies, released government records, and modern claims of hidden reverse-engineeri…🧭 Topic overview · 26 min readGovernment programs (topic)This encyclopedia overview outlines government and private programs established to study UFOs and UAPs from 1947 to 2023. U.S.🧭 Topic overview · 22 min readBeings & bodies (topic)This topic overview covers reports and claims about non-human beings, bodies, and biological material spanning from 1947 to 2023. It outlines various second-hand and anonymous accounts involving crash-retrieval stories and alien abductions, mostly centered in…🧭 Topic overview · 19 min readCrashes & retrievals (topic)This topic overview covers claims from 1947 to 2023 that governments have recovered and studied crashed non-human craft or debris. Beginning with the 1947 Roswell incident in New Mexico, ufology claims have expanded through various witness accounts and testim…

🗓️ Project Blue Book on the UAP timeline

1. 1951A Blue Book officer reportedly runs a private, Navy-assisted inquiry into undersea and aerial UAP. Read the article →
2. 9 December 1952An Air Force colonel stops Blue Book's Edward Ruppelt from sharing strong cases with the CIA before the Robertson Panel. Read the article →
3. 26 August 1953Air Force Regulation 200-2 tightens UAP reporting and routes key reports away from Project Blue Book. Read the article →
4. 5 May 1955Blue Book Special Report No. 14 analyzes 3,200 sightings and finds no proof of advanced craft. Read the article →
5. 5 July 1956Rep. John Moss asks why the unclassified Blue Book Special Report 14 isn't public. Read the article →
6. 5 April 1966The Blue Book chief tells Congress there are no unexplained radar cases, contradicted by records. Read the article →
7. May 1972Blue Book adviser J. Allen Hynek writes that Blue Book was a cover-up and the problem was glossed over. Read the article →
8. 28 October 1972An NSA official tells Vallée a Wright-Patterson office kept secretly analyzing UAP after Blue Book. Read the article →
9. April 1975Blue Book files are withdrawn from public access; some papers are allegedly destroyed or redacted. Read the article →
10. 1977Attorney Daniel Sheehan says he was shown classified Blue Book material at the Library of Congress. Read the article →
11. January 1989Bill English claims he saw a memo saying Blue Book officials knew of crash recoveries. Read the article →
12. 24 January 2000Bigelow tells Vallée of an idea to push Congress for a new Project Blue Book. Read the article →
13. 17 December 2001A researcher finds a Blue Book file showing a Battelle scientist reported his own sighting. Read the article →
14. 6 March 2015The same contractor tells Podesta about a Blue Book veteran he met. Read the article →

Search the timeline →

🏛️ Official records

• Project Blue Book Special Report No. 14 (Analysis of Reports of Unidentified Aerial Objects)CIA · Released Jun 12, 2026This is the USAF Project Blue Book with a CIA cover sheet stating the document is "Official Record Copy." With the exception of the handwritten note on the first page, the content of this document has been available on …
• BAASS Project Management Plan, December 2008Department of War · 2008-12-02This document is an administrative, programmatic, or contractor-produced record related to the Advanced Aerospace Weapon System Applications Program (AAWSAP), a Defense Intelligence Agency (DIA)-administered program act…
• Australian Dept of Defense Scientific and Intel Aspects of the UFO ProblemCIA · 1971Dated to 1971, an Australian review of the USAF Project Blue Book. This document was released by the National Archives of Australia. 
• The Condon Report (1969)University of Colorado for the U.S. Air Force · January 1969“Scientific Study of Unidentified Flying Objects”: an Air Force-funded study led by physicist Edward Condon at the University of Colorado from 1966 to 1968.
• Department of the Air Force Committee to Review Project Bluebook, 1966-1967Department of War · 1967-04-17This file documents the 1966-1967 deliberations and recommendations of the U.S. Air Force (USAF) Scientific Advisory Board’s Ad Hoc Committee to Review Project Blue Book. Project Blue Book was a 1952-1969 USAF program t…
• Final Personnel Record for Newhouse, Delbert C., U.S. Navy, 1957Department of War · 1957-05-02This file contains the final personnel record of U.S. Navy Chief Warrant Officer Delbert C. Newhouse, who left naval service as a Chief Warrant Officer 4, then the highest Warrant Officer grade. In July 1952, Newhouse r…
• Correspondence Relating to Project Blue Book, 1955Department of War · 1955This file contains correspondence relating to Project Blue Book, a 1952-1969 U.S. Air Force program to investigate the nature and origin of unidentified flying objects (UFO). The correspondence includes letters and memo…
• Project Blue Book Photo File Relating to Tremonton Film, Utah, 1952Department of War · 1952-07-02During its investigation of a July 1952 film of an incident reported near Tremonton, Utah, Project Blue Book examined whether the objects recorded on film might have been “pillow balloons.” Project Blue Book was a U.S. …
• Project Blue Book File on Tremonton Film, Utah, 1952Department of War · 1952-07-02This document records the Project Blue Book investigation and subsequent assessments of an incident near Tremonton, Utah, on July 2, 1952. Project Blue Book was a 1952-1969 U.S. Air Force program to investigate the natu…
• Presentation by Captain Edward J. Ruppelt, 1952Department of War · 1952-03-26This audio file records a March 1952 presentation by Captain Edward J. Ruppelt, outlining the U.S. Air Force’s reorganized investigation into unidentified flying objects (UFOs). The presentation previews prospective tec…
• Transcript of a Presentation by Captain Edward J. Ruppelt, 1952Department of War · 1952-03-26This document is a transcript of a March 1952 presentation by Captain Edward J. Ruppelt outlining the U.S. Air Force’s reorganized investigation into unidentified flying objects (UFOs). The presentation previews prospec…
• Project Blue Book (1952–1969)U.S. Air Force · National Archives · 1952 – 1969The Air Force’s long-running study of UFO reports, which followed the shorter Project Sign (1947–48) and Project Grudge (1949). Its case files are now held by the National Archives.

🛸 UFO sightings about Project Blue Book

Sightings that mention Project Blue Book

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More in the encyclopedia

Other articles that link to or mention Project Blue Book:

• Proposal for a new Project Blue Book (2000)In January 2000, Robert Bigelow told Jacques Vallée about an idea from technology company president Jim West to engage Congress to create a new official UFO study like Project Blue Book. The initial …
• Transfer of the Blue Book files (1975)In 1975, the United States Air Force withdrew the Project Blue Book UFO files from public access for a security and privacy review. During this process, reviewers blacked out witness names and allege…
• Bob Fish email on a Blue Book veteranIn 2015, former defense contractor Bob Fish sent an email to John Podesta detailing a secondhand account from an unnamed Air Force veteran about tracking UFOs off the coast of Florida. According to t…
• Howell McConnell and post-Blue Book analysisThis article discusses National Security Agency official Howell McConnell and his 1972 inquiry to researcher Jacques Vallée regarding alleged secret post-Project Blue Book UFO analyses at Wright-Patt…
• Daniel Sheehan and the Blue Book photosConstitutional lawyer Daniel Sheehan claimed that in May 1977 he viewed classified Project Blue Book materials at the Library of Congress, where he saw photographs of a crashed disc-shaped craft in t…
• Bill English and Grudge/Blue Book Report 13Former U.S. Army Special Forces captain William "Bill" English claimed that in June 1977 at a British listening post, he was ordered to analyze a top-secret document called "Grudge/Blue Book Report N…
• Projects Sign, Grudge and Blue BookProjects Sign, Grudge, and Blue Book were three successive United States Air Force investigations of unidentified flying objects based at Wright-Patterson Air Force Base in Ohio from 1948 until the e…
• Project Blue FlyProject Blue Fly was a US Air Force operation established by 1960 to quickly deliver recovered foreign space hardware and other intelligence items to the Foreign Technology Division. The program reli…
• Proposal to collect UFO home movies (1950)This article is about a 1950 United States Air Force memorandum concerning senior officers attempting to covertly acquire a Louisville newsman's film of a flying disc. The event took place in July 19…
• Air Force proposals to improve UFO work (1961)Between June 1960 and March 1961, the Air Technical Intelligence Center at Wright-Patterson Air Force Base developed proposals to improve its UFO work after inquiries from congressional staff. The re…
• Project Grudge data and the artifact fileIn January 2009, journals from Jacques Vallée recorded statements that a Bigelow Aerospace Advanced Space Studies (BAASS) team member planned to visit Area 51 to retrieve Project Grudge-era data and …
• Hynek on the Robertson Panel's legacyThe article describes the CIA-sponsored Robertson Panel, which met in January 1953 to review Air Force UFO evidence and address national security and public concern. The panel concluded that UFO repo…
• Gerald Ford's call for UFO hearingsIn March 1966, U.S. House Republican leader Gerald Ford called for a congressional investigation into UFO sightings in Michigan after the Air Force dismissed them as swamp gas.
• Air Force Regulation 200-2Air Force Regulation 200-2 was a United States Air Force directive first issued on August 26, 1953, that governed how unidentified flying objects were reported and investigated. The regulation establ…
• Rendlesham Forest incidentThe Rendlesham Forest incident involved reported sightings of unexplained lights and an alleged craft landing by U.S. Air Force personnel in Rendlesham Forest, Suffolk, England, in late December 1980.
• Urner Liddel's Skyhook balloon explanationIn February 1951, nuclear physicist Urner Liddel claimed that the Navy's secret "Skyhook" research balloons accounted for every reliable flying saucer report. Although treated as the first official e…
• Betty and Barney Hill incidentThe Betty and Barney Hill incident occurred on the night of September 19–20, 1961, along U.S. Route 3 in the White Mountains of New Hampshire.
• Central Intelligence AgencyThe Central Intelligence Agency (CIA) is the United States civilian foreign intelligence agency created in 1947. Between the late 1940s and 1960s, the agency closely monitored UFO reports primarily f…

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