Project 10073 Record Card and Intelligence Spot Reports — Yuma, Arizona, April 1952

This collection of documents details an unidentified aerial phenomenon sighting reported by meteorological personnel at the Yuma Test Station in Arizona. On the afternoon of April 17, 1952, between 1505 and 1510 hours, a group of military personnel, including a lieutenant with a background in meteorology, observed a flat-white, circular object while on a hike along the Colorado River. The object was described as having no sheen and moving in a 60-degree azimuth with a slightly erratic trajectory. It left a thin, intermittent, non-persistent vapor trail approximately one to two object diameters in length. The observers, who were trained in tracking meteorological balloons with optical equipment, noted that the object was visible for approximately seven seconds and subtended an angle of one-quarter inch at arm's length. They reported that the object's motion was too fast and erratic to be tracked using a theodolite, even with the gears disengaged. A second sighting occurred on April 18, 1952, involving similar characteristics, though no vapor trail was observed during the second event. The personnel involved, including engineers and experienced weather observers, explicitly stated that the object was unlike any natural phenomenon they had previously encountered and did not believe it could be mistaken for a weather balloon. The reports were forwarded through military channels, including the Sixth Army and the Air Technical Intelligence Center (ATIC), under the project designation Project 10073. Despite the detailed observations provided by the military witnesses, the official conclusion recorded in the documents remained 'no conclusions' or 'insufficient data for evaluation.' The documents include record cards, formal intelligence spot reports, and internal military correspondence requesting further details on the sightings.