The Chase
On January 7, 1948, the control tower at Godman Army Airfield, Fort Knox, Kentucky, and state police were tracking a large, bright object in the afternoon sky. Four Kentucky Air National Guard P-51 Mustangs on a ferry flight were asked to investigate. Captain Thomas F. Mantell, a decorated WWII transport pilot, led the climb toward it, radioing that it was metallic and "tremendous in size."
His wingmen, without oxygen, leveled off. Mantell kept climbing past 20,000 feet, also without oxygen, lost consciousness, and his aircraft came apart in a dive and crashed on a farm near Franklin, Kentucky. He was the first person to die in pursuit of a UFO, and the press treated it as proof that the saucers were dangerous.
The Venus Explanation
The Air Force's new Project Sign said Mantell had chased the planet Venus. It was a poor fit: Venus was in roughly the right direction but too faint in daylight to be what the tower, the police, and the pilots described, and the explanation was widely mocked. Project Blue Book's later chief, Edward Ruppelt, wrote that the Venus answer had damaged the Air Force's credibility for years.
The Skyhook Balloon
The real answer was classified at the time. The Navy's Project Skyhook was flying enormous polyethylene research balloons, a hundred feet across, to altitudes above 60,000 feet, and a Skyhook launched from Clinton County Army Air Field in Ohio that morning was in the right place. In afternoon sunlight, the balloon would have appeared as a huge, silvery, slow-moving object, unreachable by a fighter, which is exactly what Mantell chased. Ruppelt reached this conclusion in 1952 and it has held up.
What It Changed
Mantell's death made UFOs a matter of flight safety and gave the subject its first martyr. It also established a pattern that would repeat for decades: a sincere, competent witness, a real object, an official explanation offered too fast and too thin, and a public that concluded the truth was being hidden. The truth, in this case, was a secret balloon, and the secrecy did the damage.
Frequently asked questions
What happened to Captain Thomas Mantell?
On January 7, 1948, he climbed his P-51 above 20,000 feet without oxygen while chasing a large bright object over Kentucky, blacked out, and crashed near Franklin, Kentucky. He was killed instantly.
What did Mantell actually chase?
Almost certainly a Navy Project Skyhook research balloon, a classified hundred-foot polyethylene balloon flying above 60,000 feet, which would have looked like a huge metallic object he could never reach. The Air Force's first explanation, the planet Venus, did not fit.