Bunker Hill AFB, Ind., September 1959September 1959

On September 13, 1959, control tower personnel at Bunker Hill Air Force Base in Indiana spotted an unusual object high in the sky. It was first reported by a civilian pilot flying toward La Porte, Indiana, who alerted the tower around 1530 (3:30 p.m.). The object had a pear shape and appeared roughly the size of a dime held at arm's length. Its color shifted between white, cream, and metallic tones. Something appeared to be trailing underneath it. The observers watched it move slowly from north to southwest, rising slightly, until it faded from view at dusk. By then, the object had been under observation for approximately nine and a half hours.

Several aircraft tried to get a closer look. A T-33 jet was sent to intercept the object and climbed to 37,230 feet, but the pilot reported the object remained well above him. A Mooney aircraft also climbed toward it, reaching 16,872 feet, and its pilot likewise said the object was extremely high. The estimated altitude was 55,000 to 60,000 feet. The object was tracked from multiple locations on the ground, including Bunker Hill AFB itself, Burrows, Kokomo Municipal Airport, and Logansport, Indiana. Binoculars were used by some tower operators to get a better view.

The investigating officer, Captain George R. Van Dyke, concluded that the object was a balloon of unknown type. The base did not receive any calls from the public about the sighting, though the Logansport Police Department fielded numerous inquiries. Most witness statements agreed about what was seen. One exception was a student pilot flying a Cessna 172 who said the object appeared to be coming directly at him and reacted by swerving sharply to the right. The officer noted that the pilot's inexperience likely led him to misidentify the balloon as an aircraft. To determine whether a weather balloon had been released in the area, the Kokomo Municipal Airport contacted weather stations within a 125-mile radius. All replied that they had not launched a balloon.

The Air Force concluded the object was probably a balloon, though they could not confirm which organization had released it. General Mills, Raven Industries, and Goodyear were considered as possible sources, but none confirmed responsibility. Because the balloon's origin could not be verified, the official evaluation remained "unidentified." The complete case file, consisting of 12 pages, is reproduced below as held by the National Archives.