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Near Cooperstown in Griggs County, North Dakota — The American Midwest (Upper Plains)
 

Launcher Closure Door

Ronald Reagan Minuteman Missile State Historic Site

— November-33 Launch Facility —

 
 
Launcher Closure Door Marker image. Click for full size.
Photographed By Ruth VanSteenwyk, July 24, 2020
1. Launcher Closure Door Marker
Inscription.   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.
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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
Launcher Closure Door Marker image. Click for full size.
Photographed By Ruth VanSteenwyk, July 24, 2020
2. Launcher Closure Door Marker
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).

 
Erected by State Historical Society of North Dakota.
 
Topics. This historical marker is listed in this topic list: War, Cold. A significant historical year for this entry is 1966.
 
Location. 47° 26.391′ N, 98° 3.97′ W. Marker is near Cooperstown, North Dakota, in Griggs County. Marker can be reached from North Dakota Route 200, 0.2 miles east of 116th Avenue NE, on the right when traveling east. Touch for map. Marker is at or near this postal address: 11622 ND-200, Cooperstown ND 58425, United States of America. Touch for directions.
 
Other nearby markers. At least 8 other markers are within 3 miles of this marker, measured as the crow flies. Missile Transport (here, next to this marker); Launch Facility Security (a few steps from this marker); Missile Maintenance (a few steps from this marker); More than Meets the Eye (a few steps from this marker); The Minuteman: America's "Ace in the Hole" (within shouting distance of this marker); Strategic Arms Reduction Treaty (START) (within shouting distance of this marker); November-33: "Ace in the Hole" (within shouting distance of this marker); Opheim Cabin (approx. 2.7 miles away). Touch for a list and map of all markers in Cooperstown.
 
Also see . . .  Ronald Reagan Minuteman Missile State Historic Site Information
November-33 wide view image. Click for full size.
Photographed By Ruth VanSteenwyk, July 24, 2020
3. November-33 wide view
. (Submitted on March 26, 2021, by Ruth VanSteenwyk of Aberdeen, South Dakota.)
 
Historic Site Sign image. Click for full size.
Photographed By Ruth VanSteenwyk, July 24, 2020
4. Historic Site Sign

Ronald Reagan Minuteman Missile
State Historic Site
November-33
State Historical Society of North Dakota

 
 
Credits. This page was last revised on March 27, 2021. It was originally submitted on March 25, 2021, by Ruth VanSteenwyk of Aberdeen, South Dakota. This page has been viewed 466 times since then and 148 times this year. Photos:   1, 2, 3, 4. submitted on March 26, 2021, by Ruth VanSteenwyk of Aberdeen, South Dakota. • Mark Hilton was the editor who published this page.

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Jul. 23, 2024