Why this part of a missile silo is important

America's force of inter-continental ballistic missiles, also known as ICBMs, has long been a component of the nuclear triad. The 450 LGM-30 Minuteman IV missiles split between F. E. Warren Air Force Base in Wyoming, Minot Air Force Base in North Dakota, and Malmstrom Air Force Base in Montana provide a very responsive retaliatory option – capable of hitting a target in less time than it takes to get a pizza delivered.

These missiles are kept in silos at those three bases. The silos protect the missiles from the elements – and thus, a lot of work goes into making sure that the missiles are protected, but can be quickly launched. These silos also provide protection from nuclear strikes by the enemy trying to take them out (America, it seems, never got into road-mobile or rail-mobile ICBMs). How do they balance the need for a quick response with protecting the missiles?

The key to this is the door of the missile silo.

This is one of the little secrets about ICBMs. For a very powerful weapon (each LGM-30 carries a single W87 warhead with a yield of 300 kilotons – about 20 times as powerful as the 15-kiloton bomb dropped on Hiroshima), they are very delicate instruments. As in: "Fragile, handle with care."

In other words: "Use these and it's the end of the world."

Even "routine" maintenance of a LGM-30 Minuteman intercontinental ballistic missile is a high-stakes affair.

(U.S. Air Force photo)

For instance, according to a report by Time magazine, a dropped tool destroyed an Air Force LGM-25 Titan II missile, and its silo, in 1980. This fatal incident (one airman died) shows just how little it can take for things to go wrong with an ICBM.

A dropped socket wrench destroyed a Titan missile, like this one.

(Photo by Mathew Brooks)

Now, when nukes are involved, the stakes are high. This is also true when using them. Things have to work, and they have to work the first time. If the roof on your convertible is stuck in the down position, you can get it fixed and the car detailed. That's just a major inconvenience.

An ICBM silo door getting stuck – that can be devastating.

Thankfully, this Minuteman launch was only a test. If this had been for real, we'd be seeing lots of mushroom clouds.

(U.S. Air Force photo)

Fortunately, there has never been a need to use ICBMs against an enemy. But the effort is always made to ensure the systems are reliable – because one can never know. You can see the testing of an ICBM silo door in the video below.