UGM-27 Titan II
A second-generation U.S. intercontinental ballistic missile, the UGM-27 Titan II had unusually high warhead throw-weight, which let it lift the 9-megaton W53. The 54 missiles, deployed from 1962 to 1984, were reserved for the most hardened Soviet targets. They were also used as the space launch vehicle for the manned Project Gemini.
Later LGM-30 Minuteman missiles had much greater accuracy than the Titan II, so some of the same targets were now vulnerable to a more precisely placed 2MT W56, or the even more precise 340 KT W78 multiple independently targetable warhead or 300 KT W87 single warhead.
On 19 September 1980, a U.S. missile crewman, working on a missile in an open silo at Little Rock Air Force Base in Arkansas, dropped a socket wrench weighing perhaps one pound, into the silo, where it hit the outer skin of the fueled rocket at approximately 6:30 PM. At approximately 3 AM the next morning, the rocket exploded, killing 1, injuring 23, and propelling the W53 warhead several hundred feet away. The nuclear weapon demonstrated its safeguards by not partially or fully detonating. That there was no detonation even of the Cyclotol/Composition B high explosives is impressive, as the explosive compression system of the W53 did not use one of the newer, safer insensitive high explosives. In spite of this incident, or perhaps because of it, the Titan II was considered a quite reliable rocket. After retirement, the Titan IIs were used as space launch vehicles, as, for example, in the Gemini program. Titan III boosters actually preceded the use of Titan II's; the Titan III used the basic Titan II design, but with strap-on solid boosters and a variety of upper stages. NASA, however, refurbished retired ICBMs for space use.
- The Encyclopedia of Arkansas History and Culture, Titan II Missile Explosion