Balloon-shaped Object Reported at Stockton Naval Supply Annex, Stockton, California, 1 January 1951

This document collection details the investigation into a sighting of a balloon-shaped object that occurred on January 1, 1951, at the Stockton Naval Supply Annex in Stockton, California. According to reports, a red and green object descended upon the depot and exploded upon contact with the ground. The remaining debris burned until it was extinguished by naval security guards. The residue was subsequently recovered and sent to the FBI laboratory for examination. The investigation, conducted under Project 10073, involved multiple military branches, including the Office of Special Investigations (OSI) and the Air Materiel Command (AMC). Initial reports noted the recovery of a bamboo ring from the debris, which prompted speculation regarding potential tropical or oriental construction. However, subsequent FBI laboratory analysis concluded that the object was likely a home-made hot air balloon. The FBI found no fingerprints of value on the bamboo ring and noted that the wires and other materials did not suggest a specific foreign source. The Air Materiel Command further suggested that the explosion might have been caused by the malfunctioning of an electrical circuit, noting that high-altitude balloons often use explosive caps to disconnect equipment at specific altitudes. The correspondence confirms that the information was disseminated to G-2, the Army, the Office of Naval Intelligence (ONI), and the Air Materiel Command, while emphasizing that the information was derived from non-USAF sources and should be handled within established USAF channels. The documents include various routing sheets, memoranda, and indorsements between February and April 1951, documenting the administrative process of investigating the incident and the eventual conclusion that the object was a hot air balloon.