The biggest threat during the Cold War was a nuclear attack by the Soviet Union. However, during those difficult times, the United States came perilously close to nuclear war for a short spell.
On January 23, 1961, the United States nearly avoided a catastrophic disaster when two Mark 39 hydrogen bombs were accidentally dropped over Goldsboro, North Carolina. When a US Air Force B-52 bomber broke apart in mid-flight, the explosives exploded. However, one of the bombs worked just as it should have: its parachute deployed, its trigger mechanisms functioned, and a single low-voltage switch miraculously saved the day.
“Keep 19,” a Boeing B-52G-95-BW Stratofortress assigned to the 4241st Strategic Wing, was on a 24-hour airborne alert mission off the United States’ Atlantic Coast. The Strategic Air Command flew B-52 bombers equipped with nuclear weapons flying 24 hours a day, seven days a week during the Cold War.
The plane was piloted by Capt. Richard W. Hardin and 1st Lt. Adam C. Mattocks. It was directed by Maj. Walter S. Tulloch of the US Air Force. It was armed with two Mark 39 thermonuclear bombs, each with a 3–4 megaton explosive yield.
The Mark 39 was a two-stage, radiation-implosion thermonuclear bomb developed in 1957 and 1959 that could be detonated by ground contact as an airburst or “lay down.” A system of parachutes would slow the bomb, and it would touch down on its target before detonating, giving the bomber time to get out of the blast zone.
The Mark 39 was a light weapon with a 3.8 megaton explosive yield, 250 times the Hiroshima bomb’s explosive yield and enough to kill everyone and everything within a 17-mile radius.
The B-52 was refuelling in flight from an air tanker only three days after President John F. Kennedy assumed the presidency when the tanker’s crew told Major Tulloch that the B-52’s right wing was leaking fuel. As the B-52 passed above, almost 5,400 gallons (37,000 pounds) of jet fuel spilled in less than three minutes.
Due to the unstable state created by the enormous fuel load, the bomber grew more difficult to control as it descended. Finally, when the bomber’s right wing came off, it lost control, and Major Tulloch ordered the crew to evacuate the endangered aircraft. Before the B-52 exploded, five crew members could escape through the top exit. Regrettably, three crew members were killed in the disaster, which spanned two square miles.
As the B-52 collapsed, the two Mark 39 bombs were discharged. One slammed into a muddy field at about 700 mph, depositing itself 180 feet deep. The parachute on the other bomb landed almost undamaged.
In the military, an occurrence like this, including the loss of nuclear weapons, is called “Broken Arrow.”
The buried bomb proved challenging to recover, but the ordnance crew was able to recover the majority of the weapon after eight days, including the 92 detonators and conventional explosive “lenses” of the “primary,” the first stage implosion component. In addition, the weapon’s uranium-235/plutonium-239 “pit,” or core, was recovered on January 29. However, the “secondary” was never located.