Project Blue Book Case File
Danville, CaliforniaSeptember 1952
Summary
On September 4, 1952, a resident of Danville, California saw a shiny, circular object streaking across the sky in broad daylight. The observer watched it for about thirty seconds as it flew straight and level to the south, moving faster than any jet aircraft and making no sound. The Air Force received a report of the sighting and sent out a detailed questionnaire to gather more information from the witness.
The case file indicates the sighting occurred at 1730 (5:30 p.m.) Pacific Daylight Time. The observer was located about one mile east of Danville, with the object visible to the south. Weather conditions at the time were cloudy with north winds. The observer was certain about the timing and direction but did not report the object's altitude.
Investigators at the Air Technical Intelligence Center at Wright-Patterson Air Force Base in Ohio noted that the report was sketchy and incomplete. The evaluation form shows the Air Force considered several explanations: balloon, aircraft, or astronomical phenomenon. Ultimately, the Air Force rated the sighting as "unidentified," meaning investigators could not determine what the object was. However, they also marked "probably balloon" as a possible conclusion, suggesting that interpretation was considered even as the case remained officially unresolved.
The full case file, comprising 18 pages as held by the National Archives, is reproduced below.
Reported location
Danville, California
Date of incident
September 1952
State / country
CA / US
Page count
18 scanned pages
USAF evaluation
unidentified
Microfilm
T1206, Roll 15