Government / Military

Project SIGN

1948-01-23 – 1949-02-01what this date marks, in the notes below

The first official, high-priority USAF UFO programme, formalized out of Project SAUCER. The Air Technical Intelligence Center assumed control of it on January 23, 1948 - the centre that later became the National Air and Space Intelligence Center. "The impetus for this effort was to determine if these objects might be Soviet secret weapons or 'extra-planetary' objects", and its staff reviewed the military's intelligence on German weaponry to see whether any had fallen into Soviet hands. It evaluated 243 reported sightings and concluded in February 1949 that "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", finding nearly all were caused by "misinterpretation of known objects, hysteria, hallucination, or hoax" - while not ruling out the possibility of extraterrestrial phenomena. AARO also records, with its own hedge that "the historical account is unsubstantiated and derived from only one source", that SIGN staff in late July 1948 allegedly drafted a report - the "Estimate of the Situation" - concluding UFOs were "interplanetary" in origin, and that USAF Chief of Staff General Hoyt S. Vandenberg rejected it as lacking proof.

In the UAP recordRuled into the unidentified-phenomena thread on 2 September 2026 from this entity's own name and role text, which contain: "aaro", "ufo", "project sign". An editorial classification of what thread this entity belongs to; it rests on no page and does not claim to. Neighbours were not used - see apply-subjects-2026-09-02.mjs for why.

3 of 3 connections resolve to a document you can open.

2 notes on how this record was made

Documents1 behind a connection1 more that names it

Documents behind a connection

Report on the Historical Record of U.S. Government Involvement with Unidentified Anomalous Phenomena (UAP), Volume I 2024-02-01

Also named in documents we hold

This entity's name appears in the 2 documents below. That is the entire claim. Nothing here is evidence for anything on this map, no connection rests on it, and it says nothing about what the document is about. It is a place to look next.

Report of Air Force Research Regarding the "Roswell Incident"

named on a page we have read · p. 13

…n of UFOs reported in Project Bluebook or its predecessors, Project Sign and Project Grudge, which ran from 1948-1969.

Report on the Historical Record of U.S. Government Involvement with Unidentified Anomalous Phenomena (UAP), Volume Ialready cited above

named on a page we have read · p. 14

…uppelt claimed that Project SAUCER was the informal name of Project SIGN and it was designated a high priority. However, in an inter…

3 connections

→ Project SAUCER

Report on the Historical Record of U.S. Government Involvement with Unidentified Anomalous Phenomena (UAP), Volume I

This map says

closely connected to it and, in the report's words, "essentially the same organization"

The document says

Some of these efforts, including Projects SAUCER and SIGN, were closely connected and essentially the same organization.

Report on the Historical Record of U.S. Government Involvement with Unidentified Anomalous Phenomena (UAP), Volume I, 2024
printed p. 13 · read off the page footer; the printed number matches the PDF page on every page held from this report
rendered and read by eye — the grade this project quotes from

Caveat THE REPORT IS NOT SURE THESE WERE TWO THINGS, AND THIS EDGE IS DRAWN THAT WAY. Printed 14 quotes Captain Edward Ruppelt saying SAUCER was simply the informal name of Project SIGN, and a Project SIGN employee saying the work began a year earlier, in 1946, with SAUCER as its original informal name. Against that, the report gives each its own titled section, date range and Results paragraph. The two nodes exist because the report treats them as two entries; this edge exists because the report says they may be one thing. AN EARLIER DRAFT OF THIS CLAIM SAID "formalized out of it", which asserts a sequence the source does not settle. It was rewritten when a gate found it standing on a sentence this project had read but never quoted.
← Project GRUDGE (original)

same document as the row above

This map says

the same organisation renamed, in approximately February 1949

The document says

Project SIGN was renamed Project GRUDGE in approximately February 1949.

Report on the Historical Record of U.S. Government Involvement with Unidentified Anomalous Phenomena (UAP), Volume I, 2024
printed p. 15 · read off the page footer; the printed number matches the PDF page on every page held from this report
rendered and read by eye — the grade this project quotes from

Caveat A RENAMING, NOT A SUCCESSION, and the report's word is "approximately". The same page records that staff who leaned "interplanetary" were "reportedly purged" around this change - an allegation AARO attributes to "one account" rather than asserting, and which is quoted with its hedge on the GRUDGE entry.
← Hoyt S. Vandenberg

same document as the row above

This map says

rejected its alleged "Estimate of the Situation" as lacking proof

The document says

Although the historical account is unsubstantiated and derived from only one source, Project SIGN staff in late July 1948 allegedly drafted, signed, and sent a report ("Estimate of the Situation") up the military chain for approval. This report allegedly concluded that UFOs were "interplanetary" in origin, but it was rejected by USAF Chief of Staff General Hoyt S. Vandenberg as lacking proof.

Report on the Historical Record of U.S. Government Involvement with Unidentified Anomalous Phenomena (UAP), Volume I, 2024
printed p. 14 · read off the page footer; the printed number matches the PDF page on every page held from this report
rendered and read by eye — the grade this project quotes from

Caveat THE HEDGE IS IN THE CLAIM BECAUSE THIS IS A CLAIM THAT HARDENS AS IT TRAVELS. AARO introduces the whole account with "Although the historical account is unsubstantiated and derived from only one source", and writes "allegedly drafted" and "allegedly concluded". What is being recorded here is that the report says a rejection happened, on an account it says it cannot substantiate. Printed 28 adds that Ruppelt said all but a couple of copies were destroyed and that "AARO has been unable to verify his claim or locate the document". THE NODE AT THIS END IS HOYT S. VANDENBERG, THE MAN. Printed 30 of the same report names Vandenberg an Air Force base; they are not the same thing and only one of them is on this arrow.

Notes on this record

The date

The section heading gives "January 1948" with no day. The date recorded is the one precise January 1948 date in the text: 23 January 1948, when the Air Technical Intelligence Center assumed control. That is a transfer of control rather than a founding, and the distinction is left visible here rather than smoothed into a start date.

The end date

The section heading gives "February 1949" with no day, which is also when the project reached its conclusion. The first of the month is a placeholder for a month.