EPTTHE UNITED STATES successfully tested its interceptor missile defense system on Tuesday, essentially shooting an incoming missile out of the sky. An impressive technological feat to be sure, one the Pentagon likens to hitting a bullet with another bullet. But as proof that such a system could defend the US against a North Korean attack, it still misses the mark.
Think instead of the $244 million test as a competent recital, a choreographed display of US missile defense capabilities under optimal conditions. It leaves open the question of how the so-called Ground-based Midcourse Defense system would perform under real-world conditions—and how North Korea might respond to this latest demonstration of a system that US has spent almost two decades testing.
The US first tested this descendant of Reagan-era “Star Wars” missile defense ambitions in 1999. It works on a fairly straightforward underlying principle: Hit an incoming missile hard enough to destroy it.
It does this by launching a rocket, which in turn releases a “kill vehicle,” a smaller device with four onboard thrusters and internal guidance systems that send it careening into the incoming missile. The kill vehicle doesn’t carry explosives, it just packs a punch.
Simple enough in theory. The reality is a different matter.
“The ICBM that’s incoming is expected to be going 15,000 miles per hour. The interceptor will be going on the same order, maybe a little slower,” says Laura Grego, senior scientist and global security specialist at the Union of Concerned Scientists. “You’re trying to line up these refrigerator-sized things in space at the same place at the same time. That’s a tricky thing to do.”
That explains the mixed results seen thus far. The US has tested the interceptor system 19 times since 1999, succeeding about half the time. The most recent test, three years ago, marked another success, but three prior attempts fizzled. That kind of success rate is troubling, given the meticulously managed conditions. “These tests are scripted for success,” says Philip Coyle, senior fellow at the Center for Arms Control and Prevention and former head of the Pentagon’s test and evaluation office. “What’s been surprising to me as that they have failed as often as they have in spite of that.”
The US Missile Defense Agency conducts the tests, and scripts the conditions carefully. “The defenders had significant information about the target ahead of time,” says Grego. “They know what it looks like, they know when it’s coming”—factors the Pentagon almost certainly won’t know if North Korea or anyone else lets one fly.
The tests also don’t account for decoys and countermeasures that could throw off the missile defense system—tactics that include technology that confuses the launch-detecting radar systems or infrared sensors aboard the interceptor, or a simple balloon traveling alongside the incoming missile’s reentry vehicle.
All of which amounts to more caution than confidence, a note sounded even by the Pentagon. “Initial indications are that the test met its primary objective,” said Vice Admiral Jim Syring, director of the US Missile Defense Agency, “but program officials will continue to evaluate system performance based upon telemetry and other data obtained during the test.”
In other words? It worked today. But that doesn’t necessarily mean it will work tomorrow—or when the US truly needs it.
Think instead of the $244 million test as a competent recital, a choreographed display of US missile defense capabilities under optimal conditions. It leaves open the question of how the so-called Ground-based Midcourse Defense system would perform under real-world conditions—and how North Korea might respond to this latest demonstration of a system that US has spent almost two decades testing.
The US first tested this descendant of Reagan-era “Star Wars” missile defense ambitions in 1999. It works on a fairly straightforward underlying principle: Hit an incoming missile hard enough to destroy it.
It does this by launching a rocket, which in turn releases a “kill vehicle,” a smaller device with four onboard thrusters and internal guidance systems that send it careening into the incoming missile. The kill vehicle doesn’t carry explosives, it just packs a punch.
Simple enough in theory. The reality is a different matter.
“The ICBM that’s incoming is expected to be going 15,000 miles per hour. The interceptor will be going on the same order, maybe a little slower,” says Laura Grego, senior scientist and global security specialist at the Union of Concerned Scientists. “You’re trying to line up these refrigerator-sized things in space at the same place at the same time. That’s a tricky thing to do.”
That explains the mixed results seen thus far. The US has tested the interceptor system 19 times since 1999, succeeding about half the time. The most recent test, three years ago, marked another success, but three prior attempts fizzled. That kind of success rate is troubling, given the meticulously managed conditions. “These tests are scripted for success,” says Philip Coyle, senior fellow at the Center for Arms Control and Prevention and former head of the Pentagon’s test and evaluation office. “What’s been surprising to me as that they have failed as often as they have in spite of that.”
The US Missile Defense Agency conducts the tests, and scripts the conditions carefully. “The defenders had significant information about the target ahead of time,” says Grego. “They know what it looks like, they know when it’s coming”—factors the Pentagon almost certainly won’t know if North Korea or anyone else lets one fly.
The tests also don’t account for decoys and countermeasures that could throw off the missile defense system—tactics that include technology that confuses the launch-detecting radar systems or infrared sensors aboard the interceptor, or a simple balloon traveling alongside the incoming missile’s reentry vehicle.
All of which amounts to more caution than confidence, a note sounded even by the Pentagon. “Initial indications are that the test met its primary objective,” said Vice Admiral Jim Syring, director of the US Missile Defense Agency, “but program officials will continue to evaluate system performance based upon telemetry and other data obtained during the test.”
In other words? It worked today. But that doesn’t necessarily mean it will work tomorrow—or when the US truly needs it.
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