Introduced in the early 1970s, the Minuteman III forms the land-based component of the United States nuclear triad (nukes launches from the air and the sea for the other two legs). Four hundred Minuteman IIIs are based in hardened concrete silos across the Western states, manned by Air Force launch crews. The Minuteman III’s exact payload is a secret but believed to be a single Mk. 21 reentry vehicles with a single 300- to 475-kiloton thermonuclear warhead.
The missile disposal system is pretty straightforward, with the rocket fuel and the motor stages requiring the most work. The warhead is the most delicate part of disposal, of course, thanks to the presence of plutonium and highly enriched uranium. Although the warhead uses a considerable amount of high explosive to initiate the chain reaction in the fission primary stage, those explosives are “insensitive,” meaning they’re hard to set off accidentally. (For more on how thermonuclear weapons work, see here.)
One day, all Minuteman III missiles will be dismantled in the manner depicted in this video. The Air Force’s Ground-based Strategic Deterrent aims to replace the Minuteman III with a new, unnamed missile, although there are proposals to refurbish the existing missiles and keemp them on duty. Unlike the warheads in this video, however, the Minuteman III warheads that make up the current American arsenal probably will be recycled in some form for their eventual replacements—particularly the plutonium “pits.”