Calumet, Michigan and Lake Superior Area, April 1953April 1953

# Radar Targets Over Lake Superior

On the night of April 20, 1953, radar operators at the 665th Air Control and Warning Squadron in Calumet, Michigan tracked a series of fast-moving targets on their radar screen. Between 01:18 a.m. and 02:15 a.m., the operators logged multiple blips appearing roughly 50 miles from the station, arranged in a clockwise pattern around them. The targets moved at speeds between 1,800 and 8,400 miles per hour, far faster than conventional aircraft of that era.

The radar operators, all experienced in their work, noted that the targets appeared as sharp, well-defined blips on the scope, consistent in size and moving at constant speeds. They detected no abrupt maneuvers. The radar equipment, an AN/FPS-3 search radar with a Thyratron modulator, was functioning normally with no recent maintenance issues. Two other aircraft were known to be in the area at the time, but the fast-moving targets did not match their positions or behavior.

The night was clear enough to see the Northern Lights, though weather conditions included three miles of visibility, snow, and overcast skies. The operators noted that they could not obtain altitude readings for the targets. No photographs were taken, and no visual observations accompanied the radar sightings.

The intelligence officer who reviewed the case, Captain Russell H. Kline, commended the radar operators for their thorough reporting. He concluded that the targets most likely represented electronic interference (a type of false radar echo) from shipborne radar sets operating on Lake Superior. The Air Force officially classified the case as "Electronic Radar Interference," accepting the interference explanation as the most probable cause. The full case file is reproduced below as held by the National Archives, comprising 17 pages.