What happened
On the afternoon of 7 January 1948 the Kentucky State Police called Godman Army Airfield at Fort Knox about a large, round object drifting over towns to the east and west. Tower operators soon spotted something high to the south, and a crowd of officers, including the base commander, studied it through binoculars without being able to name it. Four Kentucky Air National Guard F-51 Mustangs were passing, and the tower asked their leader, Capt. Thomas Mantell, a decorated D-Day transport pilot, to take a look. Mantell kept climbing after his wingmen leveled off at 15,000 feet without oxygen. His last words that everyone in the tower agreed on were that he was going up to 20,000 feet. He blacked out from lack of oxygen, and his fighter spiralled into a farm near Franklin. The death of a pilot chasing a 'flying saucer' made national news and spawned lurid rumors.
The official explanation
Project Sign's first answer was the planet Venus, which Hynek later withdrew because Venus would have been too faint in the afternoon haze. Edward Ruppelt's 1952 Blue Book review concluded Mantell had most likely chased a large, then-classified Navy Skyhook plastic balloon, probably launched from Clinton County AFB, Ohio. Observers in Madisonville, Kentucky, and astronomer Carl Seyfert near Nashville looked at the object through telescopes and binoculars and described a balloon. Mantell blacked out climbing above 25,000 feet without oxygen.
The anomalous case
The Air Force got this case wrong first, rushing out the Venus answer, as Ruppelt admitted, before the rescue crews had reached the crash. Its replacement rests on an assumption: Ruppelt wrote that he never found records showing a Skyhook was launched on 7 January 1948, and that early Skyhook staff would only say maybe. The tower crew, including the base commander, watched the object for well over an hour and said they had ruled out an aircraft or weather balloon. Ruppelt also wrote that a friend of Mantell's insisted he was one of the most cautious pilots he knew, which makes a reckless climb without oxygen hard to explain unless he thought the target was worth it. Saucer historians credited Mantell with calling it metallic and tremendous in size, though tower staff could not later agree on those words. The balloon solution is plausible, but it remains a reconstruction rather than a documented match.
The strongest argument that this was something genuinely unknown or classified, with each claim attributed to the person who made it.
Documents
- Project BLUE BOOK records (National Archives, microfilm T-1206) official, archives.gov
Sources
- Mantell UFO incident Wikipedia
- The Report on Unidentified Flying Objects (Edward J. Ruppelt, 1956) Project Gutenberg
Witness reports elsewhere
These archives can't be republished here, so we link to them instead.