Congaree AFB, S.C., December 1952December 1952

On the morning of December 4, 1952, radar operators at Congaree Air Force Base in South Carolina detected an unusual object on their radar screen. The AN/MPS-5 radar set picked up the target at 0342 (3:42 a.m.) and tracked it for about five minutes. The object appeared roughly 85 miles northeast of the base at an azimuth of 34 degrees (roughly north-northeast) and disappeared about 99 miles away at 105 degrees. According to radar calculations, the object was traveling at an estimated speed of 6,000 miles per hour, completing roughly a quarter-circle path around the base.

All the radar operators who observed the blip were trained and experienced airmen. The primary operator was Staff Sergeant Donald S. Thomas, with witnesses including Airman First Class Walter Hopf, Airman First Class Arden Patefield, Airman First Class Clarence Ives, and Airman Second Class Arthur Vallier. All were graduates of radar operator school with between two and five years of experience and were considered reliable observers. The sighting was strictly electronic, not visual. Weather conditions at the time were low stratus clouds, no precipitation, and winds from the northeast at five miles per hour.

The Air Technical Intelligence Center in Washington examined the case and noted that similar radar sightings had been evaluated previously as probable interference from other radar stations. The analysis suggested that the excessive speed of 6,000 miles per hour and the object's tendency to follow the radar beam's rotation pattern might point to interference. However, the investigators determined they needed more information on local weather conditions, including temperature and moisture levels at various altitudes, before drawing a final conclusion. The case was carried as unknown pending that data.

The full case file is reproduced below as held by the National Archives in 14 pages.