/sci/ - Science & Math

>At around 6:30 p.m. CDT on Thursday, September 18, 1980, two airmen from a Propellant Transfer System (PTS) team were checking the pressure on the oxidizer tank of a USAF Titan II missile at Little Rock AFB's Launch Complex 374-7. Due to time constraints when going into the silo, a ratchet – 3 ft (0.9 m) long weighing 25 lb (11 kg) – was taken instead of the newly mandated torque wrench. The 8 lb (3.6 kg) socket for the oxidizer tank fell off the ratchet and dropped approximately 80 feet (24 m) before bouncing off a thrust mount and piercing the missile's skin over the first-stage fuel tank, causing it to leak a cloud of its aerozine 50 fuel.

>Eventually, the missile combat crew and the PTS team evacuated the launch control center, while military and civilian response teams arrived to tackle the hazardous situation. There was concern for the possible collapse of the now empty first-stage fuel tank, which could cause the rest of the 8-story missile to fall and rupture, allowing the oxidizer to contact the fuel already in the silo.

>Early in the morning of Friday, September 19, a two-man PTS investigation team consisting of Senior Airman David Lee Livingston and Sergeant Jeff K. Kennedy entered the silo. Because their vapor detectors indicated an explosive atmosphere, the two were ordered to evacuate. The team was then ordered to reenter the silo to turn on an exhaust fan. Senior airman David Livingston reentered the silo to carry out the order and shortly thereafter, at about 3:00 a.m., the hypergolic fuel exploded – likely due to arcing in the exhaust fan. The initial explosion catapulted the 740-ton silo door away from the silo and ejected the second stage and warhead. Once clear of the silo, the second stage exploded. The W53 warhead landed about 100 feet (30 m) from the launch complex's entry gate; its safety features prevented any loss of radioactive material or nuclear detonation.[5][6]