22 March 2013
What’s Happened in 30 years?
Here’s a snapshot. Since 1983, the goal of missile defense changed from protecting the U.S. public from a Soviet nuclear attack, to “enhancing deterrence” by protecting U.S. military sites, and now to stopping a small number of missiles from North Korea or Iran. Guidance and homing technology improved enough to allow development of “hit-to-kill” technology intended to destroy an incoming warhead by ramming into it; previous systems relied on nuclear-tipped interceptors to destroy a warhead at a distance.
In 2002 the Bush administration pulled the U.S. out of the Anti-Ballistic Missile Treaty that had long limited U.S. and Russian anti-missile systems so they didn’t spur an increase in offensive weapons or—more relevant today—interfere with efforts to cut nuclear arsenals. The administration then began fielding interceptors in Alaska and California; today the Ground-based Midcourse Defense (GMD) system has 30 interceptors between the two sites. It also built a huge floating Sea-Based X-band (SBX) Radar, which it argued was essential to making the system effective, but which is now semi-mothballed in port because it’s too costly to operate.
In 2009 the Obama administration announced a 10-year plan to expand the Navy’s Aegis ship-based missile defense system to include hundreds of interceptors of increasing capability for use in Europe and elsewhere. Last week it announced that it will add 14 ground-based interceptors to the Alaska site. In addition, Congress has mandated an environmental impact statement as a first step in scoping a third deployment site for interceptors, most likely on the east coast.
So, despite changing directions over the years, missile defense is continuing to expand—with a budget of more than $10 billion per year. And it allows political and military officials to point to something as a response to the North Korea problem.
Does It “Work”?
There have been a number of official statements—most recently by White House spokesman Jay Carney last week and Secretary of Defense Leon Panetta in December—expressing confidence that U.S. missile defenses could stop a North Korean missile attack.
Such statements are nonsense since there simply is no test data that sheds light on how well the defense would work against a real-world missile attack. Moreover, no one knows what North Korea might equip its missiles with to surprise and fool the defense.
To understand this disconnect, consider what it means for the system to “work.”
The goal of a missile defense is to intercept and destroy the warhead of a missile fired in a real-world situation. That requires the system to do two things. First, it must be able to reliably launch an interceptor that can guide itself to collide with a warhead that has been identified and tracked by the system’s sensors. That capability is “hit-to-kill” and is what the intercept tests conducted so far have been attempting to develop. It’s a difficult thing to do, but hitting an identifiable warhead is a well-defined technical problem and eventually this system should be able to do it with some level of reliability. That’s technically quite impressive.
Unfortunately, it’s not enough. The second thing the system must be able to do is identify the warhead in the short time available and tell the interceptor what to shoot at. That is a very different kind of problem since it’s not a well-defined technical issue—the defense is facing a reactive enemy that is designing decoys and other countermeasures in just those ways to make it most difficult for the defense. The U.S. intelligence community, among others, has said a country like North Korea developing a long-range missile would be able to add such countermeasures by the time it fired its first missile.
For example, lightweight decoys can be released with the warhead, which is itself disguised to look like a decoy (this is called “anti-simulation”). Not all the decoys need to look exactly the same; in fact the best approach is to have them all look and behave slightly differently so that nothing identifies an object as a decoy versus a warhead. Enough is known publicly about the defense system and its sensors that the attacker can design its countermeasures with the aim of denying those sensors the information the defense would need to identify the warhead.
As discussed in the recent National Academy of Sciences report on missile defense, the Pentagon still doesn’t know how to solve this problem. That’s why the large difference in technical sophistication between the U.S. and North Korea does not automatically tip the balance in favor of the U.S. in this challenge.
None of the intercept tests conducted so far of the U.S. ground-based or ship-based systems has included realistic countermeasures that you should expect in a real-world attack from North Korea. The tests haven’t even included a warhead that is tumbling—intentionally or not—which is a very hard target for interceptors to hit. Some tests have included objects referred to as “decoys” but in each case the warhead and “decoys” looked different and the interceptor was told in advance which object to attack. Such scripted tests may be appropriate at this relatively early stage of development of the system, but they do not show the system will be effective against a real-world attack.
So, if by “work” someone means successful hit-to-kill against an identifiable warhead, as in the tests, then you can say the systems “work” to some extent. When the Obama administration says Aegis is “proven” or the ground-based system can intercept missiles, that’s the definition it is using.
Of course, even in that case, the ground-based system has been having problems in tests—see below.
But that’s not what “work” should mean, because that is not something that will protect you against an actual attack. After all, if North Korea has the capability of building a long-range missile and a nuclear warhead to put on it and has the motivation to fire it at the U.S., you have to assume it also has the capability and motivation to build countermeasures into that missile to make it effective against the defense it knows the U.S. is building.
People frequently downplay the countermeasures issue, in part because it makes the problem so difficult. But unfortunately it is real. The bottom line is that it makes no sense to add interceptors and/or an east-coast deployment site until the system has been shown to be effective against a real-world threat.
The administration may view its rosy claims about its confidence in missile defense as part of deterring a North Korean launch. But political leaders may also come to believe that they have capabilities they in fact do not, and make bad decisions based on that. They should heed the words of Nobel laureate physicist Richard Feynman, who served on the presidential commission studying the 1986 explosion of the Space Shuttle Challenger and wrote:
“For a successful technology, reality must take precedence over public relations, for nature cannot be fooled.”
Test Record of the Ground-based System
The west-coast Ground-based Missile Defense (GMD) system has failed at least seven of its 15 intercept tests (the “hit” in the 2006 test was a glancing blow that did not destroy the mock warhead). And its record has not improved over time: of the seven intercept tests conducted since the system was fielded in 2004, at least four were failures.