Weapon System 107A-2 was a weapon system. I encompassed all of the equipment and even the bases for the Titan I strategic missile. The Titan I was first American ICBM designed to be based in underground silos, and it gave USAF managers, contractors and missile crews valuable experience building and working in vast complexes containing everything the missiles and crews needed for operation and survival. The complexes were composed of an entry portal, control center, powerhouse, terminal room, two antenna silos for the ATHENA guidance radar antennas, and three launchers each composed of: three equipment terminals, three propellant terminals, and three missile silos. All connected by an extensive network of tunnels. Both antenna terminals and all three launchers were isolated with double door blast locks the doors of which could not be open at the same time. This was to ensure that if there was an explosion in a missile launcher or the site was under attack, only the exposed antenna and/or missile silo would be damaged.