: A massive sliding closure at the surface, often weighing between 110 and 700 tons. In a launch event, this door is opened rapidly, sometimes using explosive charges or compressed gas, to clear the way for the missile.
Modern silo operations are rarely conducted from within the silo itself. Instead, they are part of a networked system: Working Missile Silo Facility
: A hardened underground capsule, often 60 to 100 feet deep, where a two-person "missileer" crew monitors a group of (usually ten) silos. : A massive sliding closure at the surface,