Investigation Report: Sightings of August 16, 1966

This document is a comprehensive investigation report by Project Blue Book regarding a series of unidentified aerial phenomena sightings that occurred on the night of August 16, 1966, across the North Central United States, specifically in Minnesota and Wisconsin. The investigation began following a TWX from Truax Field to Wright-Patterson Air Force Base regarding reports of a moon-like object. As investigators gathered data, they contacted numerous witnesses, including commercial pilots, flight instructors, and ground observers. The reports described a luminous, often moon-sized object that exhibited erratic behavior, including changing colors, shapes, and pacing aircraft. Pilots reported the object as being at their altitude or higher, sometimes appearing to move at high speeds. The investigation involved cross-referencing these sightings with radar data and local media reports. While some witnesses initially suspected the moon or other conventional phenomena, the consistency of the descriptions—ranging from a 'bright ball' to a 'boomerang' or 'funnel' shape—led investigators to seek a broader explanation. The investigation eventually identified the cause as a barium cloud experiment conducted by German and American scientists at the Churchill Research Range in Manitoba, Canada. A rocket launched at 2239 CDT on August 16 reached an altitude of approximately 250 miles and released barium, which created a brilliant, expanding cloud visible for hundreds of miles. Project Blue Book concluded that this release was the source of the sightings, noting that the expansion and distance of the cloud created the illusion of pacing and rapid movement for observers, particularly pilots. The report includes detailed tables summarizing witness observations, such as size, color, shape, and behavior, and concludes that the perceived anomalies were natural consequences of observing a distant, expanding chemical cloud in the upper atmosphere.