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.
The problem is thought to have been caused by faulty cabling, but no definite diagnosis has been reached.
For more on this story, read US loses control of 50 nukes in cascading failure on ZDNet UK.