Project 10073 Record Card — Larson AFB, Washington — 26 August 1951

On August 26, 1951, at 0828Z, an unidentified flying object was detected by radar at Larson Air Force Base, Washington. The object was tracked continuously for six minutes by AN/CPS-4 and AN/CPS-1 radar sets. It maintained a course of 340 degrees with slight deviations and an average ground speed of 950 mph. An altitude of 13,000 feet was recorded, though the accuracy of this measurement was questioned due to the brief duration of the detection. Two F-86 aircraft were scrambled to intercept the object, but radar contact was lost before the fighters became airborne, and a subsequent visual search yielded negative results. The reporting officer, Captain William W. Sharp, stated that current Air Defense equipment was insufficient to handle targets of this nature. Following an investigation by the Electronics Section of the Air Technical Intelligence Center (ATIC), it was concluded that the radar return was possibly caused by interference. This conclusion was based on the fact that the target was observed only on the low beam of the AN/CPS-1 radar set and that the object's path appeared to be directly approaching the station. Weather reports from the time indicated that conditions were not favorable for anomalous microwave propagation, and no temperature inversion was present.