Project 10073 Record Card — Luke AFB, Arizona, 3 March 1953

On 3 March 1953, Captain Roderick D. Thompson, an instructor pilot with the 3600th Flying Training Wing at Luke Air Force Base, Arizona, observed an unidentified aerial object while on a training mission. Flying an F-84 aircraft at an altitude between 25,000 and 30,000 feet, Captain Thompson encountered a high-altitude condensation pattern that he described as having a smooth, knifelike leading edge and an irregular trailing edge, developing into a crescent shape. The object, which remained invisible to the pilot, was estimated to be 300 to 500 feet in diameter and was traveling due west at approximately 400 mph. Captain Thompson initiated a climbing chase at full power, reaching 30,000 feet and 560 mph, but was unable to close the distance or identify the source of the pattern. He recorded approximately 30 feet of gun camera film during the encounter. The incident was reported in compliance with Air Force Letter 200-5. Subsequent analysis by the Photo Reconnaissance Laboratory at Wright-Patterson Air Force Base, Ohio, examined the gun camera film and concluded that the object producing the trail was invisible in the photographs. The analysts suggested that the trail might have been produced by two unknown aircraft flying at high altitude, noting that the trail exhibited a two-component structure, with one part likely caused by exhaust and another by lifting surfaces. The report notes that the flight paths of the observer and the object were not parallel, making precise distance and velocity calculations difficult. The incident was officially carried by Project Blue Book as an unknown, though later internal correspondence and analysis suggested the pattern was a vapor trail from unknown aircraft. The case file includes multiple messages between Luke AFB and the Air Technical Intelligence Center (ATIC) regarding the handling of the gun camera film and requests for further analysis, including inquiries into whether a B-36 aircraft could have produced the observed trail, which was subsequently dismissed by the Photo Reconnaissance Laboratory.