Project Sign is authorized and begins work

Witness account

The Air Force authorized Project Sign at the end of 1947 and assigned the inquiry to Air Materiel Command technical intelligence in January 1948. The project sought to collect and evaluate flying-object reports in their national-security context. Its work included astronomical consultation and consideration of several possible origins.

Public record

Authorization and project reports survive. A purported 1948 Estimate of the Situation favoring an interplanetary explanation is chiefly known through later participant accounts, particularly Ruppelt’s 1956 book.

Sources

• Condon Report, Section V Chapter 2: UFOs, 1947–1968
• Naval History and Heritage Command: UFO Research Guide
• Edward J. Ruppelt: The Report on Unidentified Flying Objects (1956)