All this escalation has no doubt sharpened the focus of the current E-6B Mercury crews, whose work forms the connecting thread that makes nuclear deterrence possible. But having served alongside them, I know that the work can feel oddly abstract—like doing nothing. Deterrence means having a nuclear capability that prevents other countries from attacking you, and it also means not striking first. You’re preparing for a threat that may never come; conversely, to the other side, you are that very threat. The dissonance is equal parts absurd and terrifying.
In the air or on the ground, we were always prepared for a surprise attack. In each of the continental United States’s three “areas of operation”—geographic regions where a particular combat command has authority—there’s at least one E-6B Mercury, with its 15-man crew, on alert at all times. Those of us at Tinker would take rotating shifts of an average length of 10 hours in the air.
A large part of the job was practicing for the day when we’d have to tell those manning the systems of America’s nuclear-weapons triad—whether they were in missile silos on the ground, in strategic bombers in the air, or in submarines at sea—that it was time to launch a strike. Under normal circumstances, such an order would originate with the president (or whoever was next in line in the chain of nuclear authority), and then be disseminated through the National Military Command Center (NMCC) and on to the triad.
The point of the E-6B Mercury was to stay aloft as backup to maintain a communications link in case the ground-based communications were disabled in an attack. In that case, we would need to be ready to correctly decode and transmit a genuine order to strike. So we stayed in the air and practiced decoding and transmitting training messages.
We relied on two sets of hard plastic-sealed codebooks: one for training exercises and one for a real attack. Each contained codes that allowed us to decipher what is known as an Emergency Action Message (EAM), a string of alphanumeric characters relayed by the NMCC (or, if the center had been destroyed in an enemy strike, from an alternate site). What separated a real EAM from a practice one was its characters, which indicated which codebook to refer to.
In the event of an actual nuclear strike against the United States, the E-6B Mercury would get a real EAM, and quickly identify that it was not an exercise. We would relay it to the triad. If it contained instructions to launch a nuke, the triad would do so without further verification. A real EAM is “enough” for the E-6B to relay it, and it’s “enough” for the triad to launch the nukes.
We performed daily exercises to test our responses to EAMs. Once we received an exercise EAM on our circuits from the NMCC, I had a set amount of time to determine what type of EAM it was—to determine which country or region it was directing us to strike—hand-transcribe the message, then relay it to the nuclear triad. (The recipients got these practice messages as part of their own readiness and training—the characters of the message would indicate they were not genuine.) This was much harder than it sounds: It’s easy to repeat a series of alphanumeric characters, but just as easy to make a mistake. One slip-up and I would be grounded from flying until I re-earned my job qualifications in the flight simulator. Another mistake, and my flying career would be done. There was a limit to how high the stakes were, however: In an exercise scenario, no mistake could lead to the accidental launching of a nuke.