READINESS: U.S. nuclear weapons are aging quickly. With few spare parts, how long can they last?

When hundreds of land-based nuclear armed ballistic missiles were first lowered into underground cement silos spread across the vast cornfields here in 1970, the weapons were only intended to last a decade before a newer system came in.

Fifty years later, these missiles — called the Minuteman III — are still on alert, manned by members of the U.S. Air Force in teams of two who spend 24 hours straight below ground in front of analog terminals from the 1980s, decoding messages and running tests on the missiles’ systems to check if they could still launch if needed.

But it’s not the age of weapons or the decades-old technology that troubles their operators. It’s that the original manufacturers who supplied the gears, tubes and other materials to fix those systems are long gone.

Related: Did Barack Obama Invite a Nuclear Confrontation with Russia?

UPDATE (FROM GLENN): To be honest, I feel safer with the out of date analog gear than I would with modern digital stuff.