Project Blue Book Sighting Report — Parkston, South Dakota, 15 August 1966

This document consists of a Project Blue Book sighting report and associated correspondence regarding an unidentified aerial phenomenon observed on 15 August 1966 near Parkston, South Dakota. Two highway patrolmen, identified as reliable witnesses, observed a single object for approximately one and a half hours. The witnesses described the object as being extremely bright, to the point where its shape could not be determined, and noted that it displayed a pulsating green light while moving at high speed in an up-and-down pattern. One witness compared the size of the object to a dime, while the other compared it to a quarter. The observation occurred at night under very clear conditions, and the object was reported to have emitted a buzzing sound for approximately five seconds before eventually fading into the northeast. The Air Force, represented by Major Hector Quintanilla, Jr., formally requested that the witnesses complete an FTD Form 164 to provide more detailed information, as the initial report was deemed insufficient for evaluation. The intelligence officer assigned to the case, 1st Lt. Neville C. Herbert of Sioux City Air Base, explicitly noted that he had no explanation for the sighting. The documentation includes internal military staff messages and a formal letter to the witnesses, confirming the official classification of the incident as having insufficient data for a definitive evaluation.