One in nine of the American ICBM strike force went offline on Saturday, according to a report on US magazine The Atlantic's website, as a series of control errors multiplied beyond the ability of engineers to compensate.
The squadron of 50 missiles affected is stationed at FE Warren Air Force Base in Wyoming, said the report. The weapons are controlled by five Launch Control Center computers (LCCs), which periodically interrogate the on-board guidance systems of the weapons to confirm their status. According to the report, one LCC began to ping the missiles out of sequence, causing the guidance systems to return errors.
As the errors cascaded, the engineers decided to take all of the LCCs offline, leaving the missiles in 'LF Down' status where they cannot be controlled from the ground. An official, quoted by The Atlantic, said that there were back-up systems from airborne command and control platforms. All LCCs, apart from the one malfunctioning unit that caused the error, were then returned to service.
According to the report: "We've never had something as big as this happen," a military officer who was briefed on the incident said. Occasionally, one or two might blink out, the officer said, and several warheads are routinely out of service for maintenance. At an extreme, "[w]e can deal with maybe five, six, or seven at a time, but we've never lost complete command and control and functionality of 50 ICBMs".
The problem is thought to have been caused by faulty cabling, but no definite diagnosis has been reached.