Project 10073 Record Card — Hillsborough, California, 24 August 1952

On 24 August 1952, at approximately 1730 PDT, a civilian couple in Hillsborough, California, observed two unidentified aerial objects. The objects were described as silver-gray in color and shaped like the cross-section of a cone. The witnesses estimated the objects to be between 150 and 200 feet in diameter. The objects were observed for a duration of one minute, during which they maintained a straight flight path at an estimated altitude of 12,000 feet and an estimated speed of 1,300 mph. The witnesses reported that the objects were stopping and starting intermittently. No sound was heard during the observation. The weather conditions were reported as clear with unlimited visibility, and winds at 12,000 feet were recorded at 240 degrees at 13 knots. The objects eventually disappeared by fading over the horizon. The observation point was located approximately 500 feet high in Hillsborough, California, and the objects were noted to be three miles northeast of the observation point. While there was some air traffic in the general area, the location of that traffic relative to the objects was not reported. The incident was documented on a Project 10073 record card and reported by the 28th Air Division to the Air Technical Intelligence Center (ATIC) and Air Force headquarters.