Failure Shuts Down Squadron of Nuclear Missiles

President Obama was briefed this morning on an engineering power failure at F.E. Warren Air Force Base in Wyoming that took 50 nuclear intercontinental ballistic missiles (ICBMs), one-ninth of the U.S. missile stockpile, temporarily offline on Saturday. 

The base is a main locus of the United States' strategic nuclear forces. The 90th Missile Wing, headquartered there, controls 150 Minuteman III intercontinental ballistic nuclear missiles. They're on full-time alert and are housed in a variety of bunkers across several states.

On Saturday morning, according to people briefed on what happened, a squadron of ICBMs suddenly dropped down into what's known as "LF Down" status, meaning that the missileers in their bunkers could no longer communicate with the missiles themselves. LF Down status also means that various security protocols built into the missile delivery system, like intrusion alarms and warhead separation alarms, were offline.    In LF Down status, the missiles are still technically launch-able, but they can only be controlled by an airborne command and control platform like the Boeing E-6 NAOC "Kneecap" aircraft, E-4B NAOC aircraft or perhaps the TACAMO fleet, which is primarily used to communicate with nuclear submarines. Had the country been placed on a higher state of nuclear alert, those platforms would be operating automatically because the frequencies used to transmit nuclear codes would be interfacing with separate systems, according to officials.