Minuteman Missile System Operation
Upon receiving a launch order, the two-officer crew in the underground Minuteman launch control center (LCC) would check the launch instructions and then set the required war plan and launcher selector switches. Next, the officers would insert keys into the launch switches, located at opposite ends of the LCC, and simultaneously turn the keys to initiate the automatic launch sequence. Sixty seconds later the missiles roared out of their underground silos.
Unlike the large liquid-fuel ICBMs that rose slowly into the air, the Minuteman, preceded by a large smoke ring, streaked out of the silo. Three seconds after launch the missile began a gentle turn toward the target. The first stage separated after 60 seconds at an altitude of 15 miles. The second stage separated after 117 seconds, and the third stage after 181 seconds, at which time the missile had reached an altitude of 118 miles and was traveling at a velocity of 23,000 feet per second. At the apogee of its parabolic flight path the reentry vehicle reached an altitude of 710 miles above the earth's surface.
The Minuteman II and III deployed penetration aids such as small rockets and explosive charges to help camouflage the warhead during reentry. Also, the Minuteman III carried a postboost propulsion system, sometimes referred to as a fourth stage, that precisely positioned the reentry system at selected points before releasing the penetration aids and the multiple independently targetable reentry vehicles containing the warheads.