The Titan II was the largest operational land based nuclear missile ever used by the United States. The missile had one
W53 warhead with a yield of 9
Megatons (9,000 kilotons). At launch, orders from the National Command Authority would have specified one of three pre-programmed targets which, for security reasons, were unknown to the crew. The missile base that is now the Titan Missile Museum (complex 571-7 of the
390th Strategic Missile Wing) was, at the time of closure, programmed to strike "Target Two". The missile's computer could hold up to three targets, and the target selected was determined by Strategic Air Command headquarters. To change the selected target, the crew commander pressed the appropriate button on the launch console. Target 2, which is classified to this day but was assumed to be within the borders of the former Soviet Union, was designated as a ground burst, suggesting that the target was a hardened facility such as a Soviet missile base. Targets could be selected for air or ground burst, but the selection was determined by Strategic Air Command. ==Tourist attractions==