Program · 22 January 1948 – February 1949

Project Sign

Also known as Project Saucer, Project SIGN, XS-304

Project Sign was the U.S. Air Force's first formal study of unidentified flying objects. It followed the summer 1947 wave of flying disc reports and the September 1947 opinion of Air Materiel Command, signed by Lt. Gen. Nathan Twining, that “the phenomenon reported is something real and not visionary or fictitious”. The Technical Intelligence Division at Wright-Patterson Air Force Base opened it as project XS-304 on 22 January 1948, first under the name Project Saucer. Its consultants included the astronomer J. Allen Hynek of Ohio State University, who checked reports for astronomical explanations, psychologists of the Aero-Medical Laboratory, G. E. Valley of MIT and the Air Force's Scientific Advisory Board, and the Rand Project.

Its report of February 1949 reviewed 243 domestic and 30 foreign incidents, grouped as disks, cigar shapes, spheres and balls of light, and found no conclusive evidence either way: positive proof, it said, was unlikely “without examination of the remains of crashed objects”. Its appendices weighed whether the objects could be Soviet aircraft or visitors from other planets; Valley noted that a watching civilisation might be alarmed by atomic bombs, and the Rand study put interplanetary travel at a thousand to one against. The report recommended continuing at a minimum level, and Sign was succeeded by Project Grudge in 1949.

Edward Ruppelt, who later led Project Blue Book, wrote in 1956 that Sign had produced a top secret “Estimate of the Situation” concluding that UFOs were interplanetary, rejected by the Air Force chief of staff; no copy has surfaced, and the Air Force told Congress in 1966 that no such document existed. In 1949 Sign's officers also investigated the Caldwell disk-rotor aircraft, a 1930s experimental machine found abandoned near Baltimore, and judged it could not account for the reports.

Sources: Project Sign report (Air Materiel Command, 1949) · Ruppelt presentation (1952, PURSUE) · House Armed Services hearing record (1966) · Wikipedia

Facts and claims

documented A 1948–1949 U.S. Air Force program to investigate the nature and origin of UFOs, run by Air Materiel Command. It was succeeded by Project Grudge and then Project Blue Book. Source: DOW-UAP-D097 — Project Sign Progress Report, 1948
documented Its report states that Project “Sign” was initiated by the Technical Intelligence Division, Air Materiel Command, as project number XS-304 on 22 January 1948, following a letter of 30 December 1947 on “Flying Disks”, with Ohio State University analysing reports for astronomical causes and the Rand Project studying “the remote possibility that some of the observed objects may be space ships or satellite vehicles”. Source: Unidentified Aerial Objects: Project “SIGN” (Air Materiel Command, Technical Report No. F-TR-2274-IA, February 1949)
documented The report (February 1949), based on 243 domestic and 30 foreign incidents, concluded: “No definite and conclusive evidence is yet available that would prove or disprove the existence of these unidentified objects as real aircraft of unknown and unconventional configuration. It is unlikely that positive proof of their existence will be obtained without examination of the remains of crashed objects.” Source: Unidentified Aerial Objects: Project “SIGN” (Air Materiel Command, Technical Report No. F-TR-2274-IA, February 1949)
documented In an appendix to the report, G. E. Valley of the Air Force's Scientific Advisory Board wrote that an extraterrestrial civilization “might observe that on Earth we now have atomic bombs and are fast developing rockets… they should be alarmed. We should, therefore, expect at this time above all to behold such visitations”; the Rand Project's James Lipp put space travel from elsewhere in the Solar System at “at least a thousand-to-one against”. Source: Unidentified Aerial Objects: Project “SIGN” (Air Materiel Command, Technical Report No. F-TR-2274-IA, February 1949)
claimed In his 1956 book The Report on Unidentified Flying Objects, Edward Ruppelt wrote that Sign had produced a top secret “Estimate of the Situation” which concluded that UFOs were interplanetary; no copy has been produced. — Edward J. Ruppelt Source: The Report on Unidentified Flying Objects
documented An Air Force statement printed in the record of the April 1966 House Armed Services hearing says: “There has never been a top-secret document, entitled “Estimate of the Situation,” which concluded that UFO's are interplanetary in nature.” Source: Hearing transcript: Unidentified Flying Objects — House Armed Services Committee (April 5, 1966)
documented In March 1952 Ruppelt said of the early study's specialists, among them Hynek, Valley and the RAND Corporation, that with about 300 reports “they all agreed that they didn't know exactly what they were. However, there were obviously no direct threat to the United States”, and that the project was dropped as a special project in 1949. — Edward J. Ruppelt Source: Transcript of a presentation by Captain Edward J. Ruppelt, March 1952 (DOW-UAP-D154)

Connected files

Books

The Flying Saucers Are Real (subject of)
The Report on Unidentified Flying Objects (subject of)
UFOs and the National Security State: Chronology of a Cover-up, 1941–1973 (subject of)

Documents

Unidentified Aerial Objects: Project “SIGN” (Air Materiel Command, Technical Report No. F-TR-2274-IA, February 1949) (produced)
Transcript of a presentation by Captain Edward J. Ruppelt, March 1952 (DOW-UAP-D154) (subject of)
Twining memo: AMC Opinion Concerning “Flying Discs” (prompted by) — Air Materiel Command's opinion of September 1947 recommended a detailed study under a code name
UFO Briefing Document: The Best Available Evidence (related to)

Organizations

National Air and Space Intelligence Center (run by) — AARO: ATIC, NASIC's forerunner, “assumed control of Project SIGN on January 23, 1948”
Department of War (Department of Defense) (run by)

People

Nathan F. Twining (followed from)
J. Allen Hynek (consulted) — Ohio State University analysed the reports for astronomical causes; Ruppelt names the astronomer J. A. Hynek
Edward J. Ruppelt (statements by)

Places

Wright-Patterson Air Force Base (based at) — Air Materiel Command at Wright Field took over Project Sign in January 1948, after Twining's 1947 letter

Programs

Project Grudge (succeeded by)

Official records (PURSUE)

DOW-UAP-D097 — Project Sign Progress Report, 1948 (documented in) — An initial report from Air Materiel Command on Project Sign
DOW-UAP-D180 — Final Personnel Record for McCoy, Howard M., U.S. Air Force, 1954 (documented in) — Covers McCoy's tenure at Air Materiel Command, when the Air Force began Projects Sign and Grudge

Videos

Capt. Edward J. Ruppelt's presentation on the Air Force UFO investigation, 26 March 1952 (PURSUE audio, DOW-UAP-PR160) (subject of)

Mentioned in this file

Project Blue Book (Program)
PURSUE — Presidential Unsealing and Reporting System for UAP Encounters (Program)

Mentioned in videos

Unidentified Flying Objects: The True Story of Flying Saucers (1956)