Investigation Report: Unidentified Aerial Objects - Rapid City, South Dakota and Bismarck, North Dakota, August 1953

This document is a comprehensive field report regarding a series of unidentified aerial phenomena observed in the vicinity of Rapid City and Bismarck, South Dakota, on 5 August 1953. The investigation was conducted by Captain Charles A. Hardin and Dr. J. Allen Hynek in January 1954. The sightings involved multiple military and civilian witnesses, including personnel at the Rapid City Filter Center and radar operators at Ellsworth Air Force Base. The objects were described as star-like, changing color from red to green, and exhibiting erratic movements, including rapid vertical and horizontal shifts. Some observers reported that the objects appeared to signal like a ship's blinker. Radar tracking at Ellsworth AFB confirmed the presence of unidentified blips, although some radar data was lost due to equipment failure. The report details the interrogation of various witnesses, including Sgt. Wesley Harry, who was considered a reliable observer. Investigators explored several hypotheses, including the possibility that the objects were stars (specifically Capella), weather balloons, or aircraft. However, these explanations were largely ruled out or deemed insufficient to account for the totality of the observations. The report highlights the difficulty in obtaining scientific data, noting the absence of clear photographs or tangible evidence. Despite the skepticism of some personnel, the investigators concluded that the incident could not be readily explained by conventional means. The report emphasizes the local nature of the phenomenon and the coincidental timing of sightings across different locations. Ultimately, the case was classified as 'Unsolved' by Project Blue Book, with a recommendation for further study by an astronomer. The document also includes correspondence between Dr. Hynek and Major Allen L. Atwell, discussing the reliability of the witnesses and the challenges of interpreting such reports in a scientific manner. The investigators expressed frustration with the lack of definitive data, noting that while the evidence suggested the presence of something unusual, it remained insufficient to identify the objects as anything other than unidentified.