Lackland AFB, TexasMay 1953

On May 23, 1953, a radar operator at Lackland Air Force Base, near San Antonio, Texas, picked up a series of radar blips that would puzzle investigators for weeks.

The radar scope showed five or more objects appearing on the screen at an estimated altitude of 35,000 feet, moving in a northerly direction over Monclova, Mexico, roughly 125 miles southwest of Monterrey. The targets appeared on the radar as conventional aircraft. They traveled for about 48 to 50 miles, then began to orbit in the same area. The entire observation lasted about one hour and five minutes, between 8:43 a.m. and 9:26 a.m. Central Standard Time.

The radar operators who watched the blips all worked for the 741st Aircraft Control and Warning Squadron. They were trained Air Force personnel, including Captain Ralph S. Hoggatt, who served as the operations officer. The operators noted that while the objects appeared consistent with aircraft on radar, the pattern of their movements, particularly the tight orbiting behavior, stood out. Speed estimates reached approximately 240 knots, though some uncertainty existed about exact velocity measurements.

Investigators immediately began trying to identify the objects. They contacted the San Antonio Air Route Traffic Control Center (ARTCC) and civilian airlines. Del Rio reported no aircraft in the area. Laredo mentioned a flight conducting touch-and-go landings at Eagle Pass, Texas, but those aircraft should not have been in the reported location. American intelligence officers in Mexico City were asked to determine whether Mexican aircraft were operating in the region at the time.

The answer came back: yes. The Mexican Air Force, in cooperation with the Secretariat of Agriculture, had sent several P-47 type aircraft with Mexican pilots to the Monclova area to conduct cloud seeding operations to promote rainfall. These aircraft were operating in that region precisely during the time of the reported observation. The Air Force concluded that the radar targets observed were likely these cloud-seeding aircraft, and the case was marked as unidentified pending further confirmation.

The full case file, consisting of 34 pages as held by the National Archives, is reproduced below.