Launcher Closure Door

Launcher Closure Door. Ronald Reagan Minuteman Missile State Historic Site. In front of you is a 107½-ton, 4½-foot-thick, wedge-shaped launcher closure door. Between 1966 and 1997, a few feet below this door was a nuclear-tipped Minuteman missile. The most important mission of the launcher closure door was to secure and protect the missile. , Designing the door presented challenges. The door needed to be heavy and thick enough so enemies could not move or penetrate the door and thus access the missile or its nuclear warheads. Additionally, the door needed to have enough mass and size to help the missile survive a nearby nuclear blast. However, the door could not be too heavy or too large or immovable-there were times that the door needed to be readily opened. Missile maintainers needed a door that they could open so that they could access and maintain the missiles' warheads and guidance computer. Also, when missile crews directed a launch, the door needed to open instantaneously-after all, this was the "minuteman" missile and there could be no costly delays during launch. , To provide access for maintenance, maintainers installed a temporary "pipe pusher" on the launcher closure door. The pipe pusher utilized the cogged rail between the two smooth rails to hydraulically roll the door open or close. The door's four 18-inch wheels rolled along the smooth rails. This was a steady but slow way to open the massive door. , If the remotely located Launch Control Center commanded the missile to launch, the door needed to open very quickly-in this emergency war situation a pipe pusher was simply too slow and impractical. So, in order to accomplish the remarkable feat of instantaneously opening the door, engineers developed and placed ballistic gas actuators beneath and behind the door. When the missile crew turned their keys and commanded the missile to launch, the actuators would fire and accelerate the 107 1/2-ton blast door to an almost instantaneous speed of 35 mph, while the leading wedge-shaped edge cleared debris from the door's path. , Photo captions , A "pip pusher" is inspected as members of a maintenance squadron prepare to remove the launcher closure door from a Minuteman missile silo (1991). , Once the launcher closure door is rolled back and the missile silo is opened, missile maintainers erect a metal safety barrier along the exposed launcher opening (1995). , A crowd of spectators stands along the fence outside a Minuteman missile launch silo at Malmstrom Air Force Base, Montana, to watch a test of the launcher closure door - 7,000 sandbags were needed to stop the door after its ballistic gas actuators success fully fired and started the door moving along its rails (2000).