Osan Air Base, Korea, November 1957November 1957

On the night of November 11, 1957, two U.S. Air Force enlisted men standing beside a runway at Osan Air Base in Korea saw an unusual object streak across the sky. One man watched it for 20 to 30 seconds, while the other glimpsed it for about 10 seconds. One of the witnesses was a Ground Control Approach (GCA) operator, trained in spotting aircraft and estimating altitudes and speeds.

The object appeared as a long, narrow flame with sparks trailing behind it. The men described the color as ranging from reddish-yellow to whitish-yellow. One observer estimated the flame and sparks stretched about 1,000 feet in length, comparable to a pencil held at arm's length. The object traveled in a straight, level flight path from west to east at an estimated speed of 800 to 900 knots at about 2,000 feet altitude. It disappeared into cloud cover, which the witnesses believed prevented them from tracking it further.

The Chief Radar Intelligence officer noted that he felt "certain these men saw an unusual object not of a conventional nature." He mentioned a possible connection to another sighting in Japan five days later that appeared in the Pacific Stars and Stripes newspaper, though he confirmed the witnesses had not read that article. However, the officer stated he had "no substantial idea of the possible cause of the sighting."

The Air Force's official evaluation, recorded on the case form, concluded the sighting was probably a meteor. The report sketch noted that the duration and description were consistent with meteor characteristics.

The full case file, containing 7 pages as held by the National Archives, is reproduced below.