Minuteman Missile Silo Under Construction
Workers preparing to install a reinforced steel silo liner inside Minuteman silo B-11 at Whiteman Air Force Base, Missouri, June 18, 1962
Unlike earlier aboveground ICBM facilities, all 1,000 Minuteman silos were designed to survive anything but a direct hit. Inserted into each silo was a 62 foot (18.9 meter) reinforced steel liner that was subsequently covered by poured concrete, forming the external silo wall. The missiles were then inserted into the liner and the silos covered by a heavy steel and concrete door.
Lowering the liner into the silo
Credit: U.S. Army Corps of Engineers