Provincetown, Mass., September 1950September 1950

On September 21, 1950, a radar operator at the Massachusetts Institute of Technology spotted an unidentified object on his screen while tracking two F-86 jet aircraft near Provincetown, Massachusetts. The operator had professional credentials that made him a credible witness. He had worked with radar since 1943, held a position as Staff Weather Officer with the Massachusetts Air National Guard, and had been a research associate at MIT since 1946.

According to his account, the object appeared on radar traveling north at a very high speed, on a course that would bring it toward the two F-86s flying northwest at 30,000 feet. The operator alerted the pilots by radio. The radar showed the unknown object crossing ahead of the F-86s and then making an extremely tight right turn, as if performing an intercept maneuver. The object then headed back toward Boston. The pilots reported they saw nothing, though they noted poor visibility at their altitude. Two other trained observers at MIT confirmed they saw the object on the radar scope and verified the operator's account. The estimated speed was between 1,200 and 1,320 miles per hour, and the force of the turn was calculated at around 11 to 12 G's. The radar signal from the object was strong and clear, suggesting it was large and had an irregular surface.

The Air Force's Office of Special Investigations interviewed the witnesses in October 1950 and found the primary observer's background and methodology credible. However, the investigation concluded that no further Air Force investigation would be pursued. The file notes that many people at MIT were aware of the sighting and that an account might eventually appear in newspapers. The full case file is reproduced below as held by the National Archives, 15 pages.