Kalispell, MontanaSeptember 1956

In the pre-dawn hours of September 4, 1956, a bright object appeared in the sky near Kalispell, Montana. Multiple observers, including a county supervisor, a civil defense director, and military personnel assigned to ground observation posts, watched the object through binoculars for roughly seven hours. They described it variously as bowl-shaped, tear-shaped, or resembling a grapefruit, with colors shifting from red to white to green. The object appeared to be only about the size of a dime held at arm's length, though some witnesses compared its brilliance to an automobile headlight from several blocks away. Several observers reported a fuzzy, hazy tail, and some said the object was accompanied by a misty cloud through which it seemed to vanish and reappear. The object began its movement in the south-southeast, progressing slowly southwestward, and disappeared near dawn as sunlight approached.

Five F-94 jet interceptors from Malmstrom Air Force Base scrambled to investigate, though low clouds prevented visual contact. No radar contact was ever made. Weather conditions that night were cold and dry with gusty winds predominantly from the east. The Air Force investigators noted that observers reported the object moving directly against these prevailing winds and making sharp, erratic turns.

The investigating officer from Flight 1-B, 4602d Air Intelligence Service Squadron, concluded that the sighting was caused by the planet Mars. Mars was in an exceptionally close approach to Earth in early September 1956, making it brighter than usual. The officer's reasoning noted that the observed times of the sighting aligned with sunset and sunrise, and that Mars' position in the sky matched the directions reported by witnesses. The investigators attributed the apparent size and erratic motion to magnification through binoculars and the observers' excitement and expectation. However, the file also notes certain inconsistencies, such as the reported wind direction differing from the weather service's report, and the observed motion seeming inconsistent with a stationary planet.

An additional civilian report from Dayton, Ohio, the same morning described a reddish-orange object roughly the size of a softball, eventually classified as Mars as well.

The full case file, comprising 34 pages, is reproduced below as held by the National Archives.