Chanute AFB, IllinoisJuly 1960

On the night of July 27, 1960, an airman stationed at Chanute Air Force Base in Illinois saw something bright and unusual cross the sky. Airman Stelle, a weather observer, was on duty at the base when he spotted an object with a bright green glow and an orange tail moving rapidly from southwest to northeast. The object appeared about the size of a grapefruit, with a tail roughly five and a half feet long. It moved behind a cloud layer in just five seconds, traveling at what Stelle described as rapid speed with a glow resembling an arc welder.

The Air Force investigated the sighting quickly. Officers checked with nearby air traffic facilities, including the tower at the University of Illinois airport in Champaign and the observatory there. They also contacted radar operators at a nearby Army air defense unit. Nobody else reported seeing anything unusual that night, and the radar station recorded no contacts. The weather was clear in the area, with some scattered clouds and occasional lightning from thunderstorms to the southeast.

The investigating officer noted that the sighting matched a description from a University of Illinois astronomer of a meteor entering the upper atmosphere. The Air Force also considered a weather balloon released from Peoria, about fifty miles northwest, which would have been aloft during the time of Stelle's observation. Such balloons typically stay in the air for two to three hours and can reach altitudes of 60,000 to 70,000 feet. Despite these possibilities, the Air Force officially marked the case as unidentified. The complete case file, reproduced below as held by the National Archives, spans 7 pages.