Project 10073 Record Card — Minneapolis, Minnesota, 5 January 1957

On January 5, 1957, a civilian observer in Minneapolis, Minnesota, reported a sighting of an unidentified aerial object. The witness described the object as round, solid green in color, and featuring a flashing red light that appeared every few seconds. The observer, who utilized binoculars, estimated the object's size to be smaller than a dime when viewed through the lenses. The object was initially sighted at an estimated altitude of 20,000 feet and subsequently ascended to 30,000 feet, exhibiting a back-and-forth motion. The flight path was reported as moving Northwest and then East over Lake Superior. The total duration of the observation was approximately one and a half hours. The report includes details from an operations officer, A/2C R.R. Butler, and notes that Capt. H. Hoopman at MSP confirmed that no radar contact was made regarding the object. Weather conditions at the time were described as completely clear, with an extreme temperature inversion noted from the surface to 5,000 feet. The official conclusion reached by the investigating authorities, specifically Capt. M.B. Luttrilv, was that the description, duration, and flight path of the object indicated it was likely a balloon. A handwritten note on the document suggests the possibility that the object was a large U.S. balloon.