SAN MARCOS AFB TEX, July 1952July 1952

At 10:40 p.m. on July 21, 1952, multiple military personnel stationed at San Marcos Air Force Base in Texas reported seeing a bright, circular object in the night sky. The object glowed with a brilliant blue-white light and left a trailing tail of blue light behind it. Witnesses reported no sound, and the object's propulsion system could not be identified. The sighting lasted approximately sixty seconds.

The object's behavior was highly unusual. It accelerated from a hover to speeds approaching the speed of sound, climbed at an extremely steep angle, and changed direction rapidly. One witness, a lieutenant who was driving south from the base nursery, said the object appeared as bright as looking at a white-hot piece of iron through a small hole. It rose to an estimated 15,000 to 20,000 feet, leveled off smoothly like a controlled aircraft, and then vanished as if a light had simply been switched off. Another witness and his wife, traveling near Maxwell, Texas, described seeing something that looked like an explosion with a red flame descending with a blue flare-like trail before turning white and moving south at high speed.

Five military witnesses provided statements to investigators. Their accounts differed in some details, with descriptions of the object's color ranging from blue-white to blue-green to reddish-yellow. One witness who was assigned as a fence guard believed the object passed over the base multiple times and was traveling slowly enough that it could have been used for reconnaissance. The observers were not rated or qualified observers, and the conflicting statements made analysis difficult.

The Air Force investigation found no conventional explanation. Weather conditions at the time included 2,500 feet of scattered clouds, visibility of ten miles, and surface winds from 150 degrees at 10 knots. There were no thunderstorms or inversion layers noted. No aircraft were known to be in the area at the time. No radar contact was reported, no physical evidence was recovered, and no interception was attempted. The file concludes that there was no activity or meteorological condition that would account for the sighting.

The case file consists of 18 pages held by the National Archives.