What happened
Acting on the Twining memo, the Air Force ordered Air Materiel Command on 30 December 1947 to set up a project to collect, evaluate and share all information on sightings that could concern national security. It was given priority 2A, a 'restricted' classification and the code name SIGN. Through 1948 Sign's staff at Wright Field worked the Mantell crash, the Chiles–Whitted airliner sighting and others. According to Edward Ruppelt, later head of Project Blue Book, the Chiles–Whitted case prompted Sign to write a formal Estimate of the Situation, a thick, black-covered, top secret document whose conclusion was that the objects were interplanetary. It went up the chain to Chief of Staff Gen. Hoyt Vandenberg, who rejected it for lack of proof. Ruppelt wrote that it was later declassified and burned, with a few copies kept as mementos. Sign's public report of February 1949 was cautious, and the project gave way to the far more dismissive Project Grudge.
The original account
It is Air Force policy not to ignore reports of sightings and phenomena in the atmosphere but to recognize that part of its mission is to collect, collate, evaluate and act on information of this nature. ... This project is assigned priority 2A, with a security classification of "restricted" and Code Name of "SIGN".
Maj. Gen. L. C. Craigie, Directorate of Research and Development, to Commanding General, Air Materiel Command, 'Flying Discs', 30 December 1947 (US government document, public domain; Condon Report Appendix S)
The official explanation
No copy of the Estimate has ever surfaced, and Popular Mechanics called it probably more mythological than real; in a 1966 House hearing Rep. L. Mendel Rivers said no such Estimate existed. Project Sign's own February 1949 report, and its successor Project Grudge, found nearly all cases had ordinary explanations, and Grudge blamed the rest on misidentification, mild mass hysteria, fabrication or psychopathology. CIA historian Gerald Haines describes Sign's founding premise as a national security question, not alien visitation.
The anomalous case
Ruppelt was not a fringe source. He ran the Air Force's own UFO project from 1951 to 1953 and wrote that he personally saw one of the surviving copies of the Estimate. He described its physical form, its classification, its contents, including earlier pre-Arnold reports from a Richmond weather observer and pilots, and its fate at Vandenberg's desk. He added that ATIC staff went to the Pentagon to argue for it and failed to persuade the Chief of Staff. If Ruppelt is right, the first formal assessment by the Air Force's own analysts concluded the objects were interplanetary, and the conclusion was overruled for lack of proof, not shown to be wrong. The founding directive itself confirms Sign was a real, priority intelligence project, not a public-relations exercise.
The strongest argument that this was something genuinely unknown or classified, with each claim attributed to the person who made it.
Documents
- Craigie directive establishing Project SIGN, 30 December 1947 (Condon Report Appendix S) official, files.ncas.org
- Project Sign report, February 1949 (Wikimedia Commons PDF) report, commons.wikimedia.org
- Project BLUE BOOK records (National Archives, microfilm T-1206) official, archives.gov
Sources
- Project Sign Wikipedia
- The Report on Unidentified Flying Objects (Edward J. Ruppelt, 1956) Project Gutenberg
- Condon Report, Appendix S: Craigie Directive, 30 December 1947 National Capital Area Skeptics (online edition of the Condon Report)
- CIA's Role in the Study of UFOs, 1947-90 (Gerald K. Haines, Studies in Intelligence, 1997) Federation of American Scientists (reprint of CIA article)
Witness reports elsewhere
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