Project Blue Book Case #1313. On June 20, 1952, U.S. military personnel in Korea observed an unidentified aerial object during active combat operations in the Korean War. The sighting occurred in one of the most dangerous and carefully monitored airspaces in the world — where any unidentified object could be an enemy aircraft on an attack run.
The Korean War airspace was a complex and lethal environment. U.S. Air Force fighters engaged Soviet-built MiG-15s in daily combat over "MiG Alley" in northwestern Korea, while bombers struck targets across North Korea and close air support aircraft operated at low altitude near the front lines. Ground-based anti-aircraft radar and airborne early warning systems maintained constant surveillance.
In this environment, rapid identification of aerial contacts was literally a matter of life and death. The failure to identify the object observed on June 20 meant that it did not match any known friendly, enemy, or neutral aircraft type operating in the theater. U.S. pilots were thoroughly familiar with the appearance of MiG-15s, Tu-2 bombers, and other Communist aircraft — this was something else.
UFO reports from the Korean theater were relatively rare in Blue Book files but carried particular significance due to the combat context. Several Korea-based sightings described objects that appeared to observe military operations without engaging.
The case was classified "Unknown" — an especially significant designation in an active combat zone where every unidentified aircraft was a potential threat.