6th PURSUE FILES DROP: This audio file records a March 1952 presentation by Captain Edward J. Ruppelt, outlining the U.S. Air Force’s reorganized investigation into unidentified flying objects (UFOs).
The presentation previews prospective technical methodologies that were subsequently incorporated into Project Blue Book, a U.S. Air Force program active from 1952 to 1969 that investigated the nature and origin of UFOs. Ruppelt explains that out of approximately 800 historical cases reviewed by the Air Force, approximately20% remained unexplained after technical analysis.
CAPT. RUPPELT: "Now, they have another type of phenomena or object or something floating around down that area, and that's these green fireballs...They're reported to be a brilliant, greenish-blue color, and they don't explode."