The moon made headlines last week with the appearance of a so-called “super blood moon.” Several people I talked to, though, thought that name was a bit dramatic for what they actually saw in the sky.

But 55 years ago today, the moon was a star player in a short drama that could have justified that name.

On October 5, 1960, the U.S. nuclear command center NORAD received signals from its early warning radar in Thule, Greenland, indicating that a massive Soviet nuclear attack on the U.S. was underway—with a certainty of 99.9 percent.

This radar was built in Greenland to provide an early glimpse of just such an attack and to allow time for the U.S. to launch a nuclear response. And U.S. land-based missiles were—and are—kept on hair-trigger alert so they can be launched within a matter of minutes if such a warning comes in. Even with this advance warning, the short flight time of incoming ballistic missiles (about 30 minutes) severely limits the time available for double-checking the warning data and deciding what to do. Confronted with credible warning, the president would have perhaps 10 minutes to decide whether to launch.

Various sources give different accounts of what happened next. In some, those in charge calmly checked the system and recognized the warning was false. In other accounts, there is considerably more tension and confusion—a “sense of panic”—until the situation is sorted out.

In any case, the culprit in this case was the rising moon, which—unexpectedly—reflected radar waves back to the Thule radar. The radar correctly assessed that it was seeing something big coming over the horizon in the right place for a Soviet attack. It immediately began sending urgent warning reports to NORAD.

Why does this matter?

Fortunately, this incident did not lead to disaster. And within a few weeks, scientists developed a reliable fix for this problem and the moon was no longer a source of false alarms.

But here’s what’s important: this incident resulted from a problem no one had considered when the system was being designed, and that wasn’t discovered until the system was actually being used.

And over the years the warning system has sprung other surprises, just as you’d expect from a large, complex system. These include incidents like the computer chip failures of 1980 and the training tape snafu of 1979.

While the U.S. has now hopefully sorted out many bugs like this one, other concerns remain. There may be other surprise events that are rare enough not to have occurred yet, and that will baffle those at the warning center for longer than these did. Diagnosing the problem and recognizing it as a false alarm—typically amid confusion and lack of information—is not something you want to have to do in a race against the clock.

And if an unexpected glitch like this happens at a time when tensions with Russia or China are high, that context could change the way the ambiguous warning data is viewed—and could affect the decision of what to do.

Old and new warning systems

But even if you think you trust the U.S. warning system to be reliable and have the key bugs worked out, there is the problem of the Russian and Chinese systems, which illustrate two different concerns.

Like the U.S., Russia keeps hundreds of its nuclear missiles on hair-trigger alert, ready to be launched on warning of attack. And yet key parts of its warning system are in a state of decay. And a decaying warning system raises all kinds of concerns about reliability and false warning. With President Putin blustering about nuclear weapons, this situation raises real concerns.

China, on the other hand, may soon pose a different problem. The Chinese military appears to be moving, for the first time, toward putting its missiles on high alert to be able to launch on warning of attack. This may in part be the result of the new generation of Chinese leaders having learned from the U.S. and Russia that keeping missiles on high alert is standard procedure for a nuclear state with land-based missiles.

Launching on warning, of course, requires building a warning system, which China does not currently have. But as China builds a warning system, it is certain to discover surprises and bugs just like the U.S. and Soviet Union did when they were breaking in their systems. And in the context of rising tensions in the Asia-Pacific region, those bugs could be disastrous.

The U.S. should take its missiles off alert

Given the state of missile warning systems, the risk of an accidental or mistaken launch of Russian or Chinese forces may currently or soon be bigger than the risk of such a launch of U.S. forces.

But U.S. policy sends the message that despite the end of the Cold War, and despite a secure retaliatory force in its submarine-launched missile force, keeping missiles on hair trigger alert to allow them to be launched on warning of attack is still a vital component of deterrence. It’s not surprising that China’s leaders would see that as something they should do as well.

President Obama campaigned on the promise that he would take U.S. missiles off hair-trigger alert. There are now more reasons than ever for him to fulfill that promise.

Posted in: Nuclear Weapons Tags: hair-trigger alert, launch-on-warning, nuclear weapons



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