The message
The top section of this site allows you to monitor and listen to Emergency Action Messages (EAMs). An EAM is, in the words of a 1985 Scientific American article by Ashton Carter, "a short, preformatted, encrypted message." Preformatted is what you can hear: the same shape every time.
An EAM opens with the net call, then the six-character preamble read three times with "standby," then "message follows," then the full string. Then "I say again," and the whole thing once more. Our receivers copy each one off air and a transcriber turns it into the text above.
Nobody outside the force can decode an EAM. All you can do is hear it — and if a launch order ever came, it would arrive as one of these and in the same form you can hear here.
The network
Emergency Action Messages are the coded traffic of the US nuclear forces, read aloud in the phonetic alphabet on the High Frequency Global Communications System. The primary frequency is 11175 kHz, upper sideband, and anyone with a shortwave radio can hear it.
Why shortwave? HF bounces off the ionosphere, so one transmitter reaches thousands of miles with nothing in between. Its weakness is the same sky: a nuclear burst floods the ionosphere with electrons and HF gets absorbed instead of reflected. So HFGCS is one path among several. It's the one you can hear, and because every message is encrypted, hearing it is all anyone outside the force can do.
The capsule
The messages you can hear above are meant for rooms like this one. The capsule is where an EAM lands: a command post passes it down, the console takes it in, and the crew acts on it. If an order to launch ever came, this is how it would arrive.
Sixty feet down, behind an eight-ton blast door, two officers sit a 24-hour alert in a room the size of a school bus.
The crew commander sits left, the deputy right. Between them: the launch control console, the printers, the phones, and the shelf of procedures that governs every minute.
The crew
A missile combat crew is two officers, a commander and a deputy. They go to the field together, take the capsule over from the crew before them, and hold it for 24 hours.
The day has a shape. When a message comes in, both officers have to agree it is authentic before anything else happens.
From the message to the keys
- The message: An order reaches the capsule as an emergency action message, an EAM. A command post passes the coded message to the launch control centers under it. In the capsule the message comes in through the console's communications element, which handles messages from higher authority and processes emergency action messages.
- Authenticate: Before acting, the crew has to authenticate the message. Only when both officers agree the message is authentic do they go on.
- Two officers, two keys: The system was built so that no single person could launch a missile. A crew is two officers, a commander and a deputy, and each has a launch key.
- Two capsules: One crew's keys are not enough, because the system was also built so that no single crew could launch. Normally a second capsule has to vote as well. Without that corroborating signal from another launch control center, the missile does not launch.
- What a capsule reaches: Each capsule has primary control of the ten missiles in its flight. Five flights make a squadron of 50, and each of its five capsules can command and monitor all 50.
The missile sites
Today the force is 400 Minuteman III missiles in three wings: F.E. Warren in Wyoming, Malmstrom in Montana and Minot in North Dakota. Each wing is 150 launch facilities and 15 launch control centers spread over thousands of square miles of ranchland.
The missile
The LGM-30G Minuteman III is a three-stage, solid-fuel missile, 59.9 feet long and 5.5 feet across, first deployed in June 1970. It stands in a silo on a shock-isolated suspension, under a launcher closure door. Solid fuel is why it can wait. There is nothing to pump and nothing to top off.
