[Editors note: Minor corrections and amendments have been made to Dr. Sturrock's original text.]

The history of the UFO phenomenon in the United States is long and complex. Historian David M. Jacobs has provided a comprehensive account of this history in his book The UFO Controversy in America, (1975). The book presents a detailed account of the origin of the Colorado UFO Project, of which the following is a brief encapsulation.

The United States Air Force carried out three consecutive studies of the UFO phenomenon over a 22-year period: Project Sign (1948), Project Grudge (1948 to 1952) and Project Blue Book (1952 to 1970). Although these studies and subsequent reports were initially classified, it appears that all reports (except Blue Book Special Report No. 13, if it ever existed) have now been declassified and are publicly available. [An exception is the "Estimate of the Situation" drafted by Project Sign and referred to by Ruppelt (1956) and Hynek (1972). Blue Book Special Report No. 13 may have been an initial draft of the Battelle study].

Two additional scientific studies that occurred within this timeframe deserve mention.

For a period of four days in 1953, the Central Intelligence Agency convened a panel of scientific consultants to consider whether UFOs constitute a threat to national defense. This panel included H. P. Robertson (chairman), Luis Alvarez, Lloyd Berkner, Samuel A. Goudsmit and Thornton Page; with Frederick C. Durant and J. Allen Hynek serving as associate members. The panel concluded that there was "no evidence that the phenomena indicate a need for the revision of current scientific concepts," and that "the evidence . . . shows no indication that these phenomena constitute a direct physical threat to national security" (Jacobs, 1975).

The Battelle Memorial Institute, under contract to the Air Force from 1951 to 1954, conducted the second study. It was primarily a statistical analysis of the conditions and characteristics of UFO reports, though it also provided scientific services and included transcripts of several notable sightings. The subsequent report was initially classified, though later released as "Blue Book Special Report No. 14" in 1955. It contains a wealth of information and arrives at the notable conclusion that the more complete the data and the better the report; the more likely it was that the report would remain unidentified (Jacobs, 1975).

On February 3, 1966, the Air Force convened an "Ad Hoc Committee to Review Project Blue Book." Its members included Brian O'Brien (chairman), Launor Carter, Jesse Orlansky, Richard Porter, Carl Sagan, and Willis A. Ware. The committee recommended that the Air Force negotiate contracts "with a few selected universities to provide selected teams to investigate promptly and in depth certain selected sightings of UFOs." This led eventually to the Air Force contract with the University of Colorado in October 1966. The project director was Professor Edward U. Condon, a very distinguished physicist and a man of strong and independent character. Work on this contract was carried out over a two-year period with a substantial scientific staff, resulting in the publication of the "Scientific Study of Unidentified Flying Objects" in January 1969.

Consequently, on December 17, 1969, Air Force Secretary Robert C. Seamans, Jr., announced the closure of Project Blue Book. Project Blue Book officially closed on Jan 30, 1970.