From 1947 to 1970, the United States Air Force conducted investigations into the increasing number of unidentified flying object (UFO) sightings throughout the United States. The purpose of the investigations was to assess the nature of these sightings and determine if they posed any potential threat to the U.S.
Three successive projects were created to carry out these investigations: Sign, Grudge, and Blue Book.
Blue Book was the longest and most comprehensive, lasting from 1952 to 1970. A 1966 Air Force publication gave insight into how the program was conducted:
The program is conducted in three phases. The first phase includes receipt of UFO reports and initial investigation of the reports. The Air Force base nearest the location of a reported sighting is charged with the responsibility of investigating the sighting and forwarding the information to the Project Blue Book Office at Wright-Patterson Air Force Base, Ohio.
If the initial investigation does not reveal a positive identification or explanation, a second phase of more intensive analysis is conducted by the Project Blue Book Office. Each case is objectively and scientifically analyzed, and, if necessary, all of the scientific facilities available to the Air Force can be used to assist in arriving at an identification or explanation. All personnel associated with the investigation, analysis, and evaluation efforts of the project view each report with a scientific approach and an open mind.
The third phase of the program is dissemination of information concerning UFO sightings, evaluations, and statistics. This is accomplished by the Secretary of the Air Force, Office of Information.
—Project Blue Book, February 1, 1966, p. 1. (National Archives Identifier 595175)
After investigating a case, the Air Force placed it into one of three categories: Identified, Insufficient Data, or Unidentified.
Project Blue Book, February 1, 1966, p. 2.(Records of Headquarters U.S. Air Force, National Archives)
Sightings resulting from identifiable causes fall into several broad categories:
- human-created objects or phenomena including aircraft, balloons, satellites, searchlights, and flares;
- astronomical phenomena, including meteors and meteorites, comets, and stars;
- atmospheric effects, including clouds and assorted light phenomena; and
- human psychology, including not only psychological frailty or illness but also fabrication (i.e., hoaxes).
The conclusions of Project Blue Book were:
(1) no unidentified flying object reported, investigated, and evaluated by the Air Force has ever given any indication of threat to our national security;
(2) there has been no evidence submitted to or discovered by the Air Force that sightings categorized as unidentified represent technological developments or principles beyond the range of present day scientific knowledge; and
(3) there has been no evidence indicating that sightings categorized as unidentified are extraterrestrial vehicles.
—Project Blue Book, February 1, 1966, p. 4. (Records of Headquarters U.S. Air Force, National Archives)
In 1967, the Air Force's Foreign Technology Division (FTD), the organization overseeing Blue Book, briefed USAF Gen. William C. Garland on the project. The July 7 report stated that in the 20 years the FTD had reported and examined over 11,000 UFO sightings, they had no evidence that UFOs posed any threat to national security. Furthermore, their evidence "denies the existence of flying saucers from outer space, or any similar phenomenon popularly associated with UFOs."
The FTD reiterated an expanded finding from Project Grudge: "Evaluations of reports of UFOs to date demonstrate that these flying objects constitute no threat to the security of the United States. They also concluded that reports of UFOs were the result of misinterpretations of conventional objects, a mild form of mass hysteria of war nerves and individuals who fabricate such reports to perpetrate a hoax or to seek publicity."
An independent review requested by FTD came to the same conclusion:
Briefing by 1st Lt. William F. Marley, Jr. to General William C. Garland, July 7, 1967, p. 7(Records of Headquarters U.S. Air Force, National Archives)
Looking to specific investigation files, we can see what a typical investigation was like, the kinds of documentation and information collected, the investigatory process, and how the Air Force arrived at its conclusions.
Datil, NM, 1950
Cpl. Lertis E. Stanfield, 3024th Air Police Squadron at Holloman Air Force Base in New Mexico, reported seeing a strange object in the sky on the night of February 24/25, 1950. He had a camera with him at the time and took several pictures, including the following:
The details of the sighting were included in an investigation report:
This was not the first time an unusual sighting had occurred at Holloman. In fact, it was part of a recurring pattern (and one that explains Stansfield's possession of a camera at the time of the sighting).
Report of Aerial Phenomena, Holloman Air Force Base, February 21, 1950, through April 31, 1951. (Records of Headquarters U.S. Air Force, National Archives)
At the time, Project Grudge was unable to provide an explanation. However, a decade and a half later, a similar sighting over the Soviet Union provided Blue Book with an answer: a comet.
Project 10073 Form, ca. 1965(Records of Headquarters U.S. Air Force, National Archives)
Several sightings of this kind were reported in the desert Southwest around this time. Despite the delay in reaching a conclusion, the similarity of the photographic evidence to known comet sightings led the Air Force to conclude it was dealing with a comet here too.
Redlands, CA, 1958
On December 13, 1958, a man in Redlands, California, snapped a photograph of a strangely shaped object in the sky.
Close-up photo of UFO in Redlands, CA, 1958.(Records of Headquarters U.S. Air Force, National Archives)
The UFO worksheet described the sighting in detail:
However, inconsistencies in the reporting led the Air Force to initially determine that the case was impossible to analyze accurately.
Correspondence, February 5, 1959.(Records of Headquarters U.S. Air Force, National Archives)
A final report dated January 1959, elaborated on these inconsistencies but reached a conclusion nonetheless. The observer had photographed a lenticular cloud.
All of these sighted were explained as initially misinterpreted natural occurrences. In the next post of the series, we'll turn our attention to sightings ultimately identified as human-created objects and one sighting truly classified as a UFO.