Chorwon, Korea, May 1952May 1952

On May 31, 1952, a bright unidentified object was spotted near Chorwon, Korea (in the middle of the country, near the 38th parallel) by multiple observers. An F-94 fighter jet tried to intercept it. The object was described as brilliant white and capable of maneuvering in ways that impressed both the pilot and ground observers. The sighting lasted several minutes and caused quite a stir in the investigation files.

The first sighting came from the air. An F-94 pilot and radar operator in the aircraft tried to chase the object starting around 0345 (3:45 a.m.) zonal time. The object appeared at around 8000 feet altitude initially, then climbed to 30,000 feet. According to the pilot's report, the object outmaneuvered the F-94 multiple times. When the fighter descended to intercept, the unidentified object matched the move and climbed to meet it. The two engaged in several close passes. The object showed superior speed and climbing ability. Eventually, the object pulled away to an estimated 450 miles per hour and the F-94 gave up the chase around 0355 (3:55 a.m.), heading back to base.

Ground personnel at a radar station near Chorwon also watched the event unfold visually, though their radar equipment could not track the object. One ground observer, a mechanic on guard duty, saw the object first as a round glowing thing descending from about 3600 feet to 2800 feet. It stopped, climbed back up, then moved east and west in level flight at speeds around 100 to 150 miles per hour. It made jerky movements and seemed to pulse in brightness in time with a sound "similar to a jet aircraft in flight." The observer described it as a disk shape with a brighter outer rim. Finally, it climbed steeply at about a 45 degree angle to the northeast and faded from sight.

The Air Force investigation included interviews with the observers and considered several explanations. One intelligence report mentioned that other F-94 crews in the area had recently chased lighted balloons, which led some officers to wonder if this sighting could have been a balloon with a light attached. However, the case file notes that no information on balloon releases was known. The file concludes that there is "a faint possibility of this being a balloon" but offers no definitive explanation. The sighting was officially rated as "unknown" by the U.S. Air Force.

The complete case file, consisting of 20 pages held by the National Archives, is reproduced below.