The U.S. Ground-based Midcourse Defense (GMD) anti-ballistic missile system recently completed a test of its “two-shot salvo” missile intercept technology, which was used to shoot down a “dummy” intercontinental ballistic missile (ICBM) in a test over the Pacific Ocean.
The Pentagon is touting the success of this test, claiming that it proves that the GMD system will be able to knock out enemy ICBMs before they hit targets in the U.S. homeland. But how effective is the GMD system really?
“The system worked exactly as it was designed to do, and the results of this test provide evidence of the practicable use of the salvo doctrine within missile defense,” said Air Force Lt. Gen. Samuel A. Greaves, director of the Missile Defence Agency—the arm of the Pentagon that is tasked with stopping enemy ICBMs. “This test demonstrates that we have a capable, credible deterrent against a very real threat.”
The GMD works by launching a missile to intercept another missile. Enemy warheads are tracked by satellite and radar during the midcourse phase of flight—a phase in which an ICBM travels above the atmosphere at 20 times the speed of sound. GMD missiles, launched from silos in Alaska and California, knock the ICBMs out of the sky before they accelerate toward the earth to detonate their payload.
This will sound familiar to those who grew up in the last decade or so of the Cold War, when then U.S. President Ronald Reagan announced the Strategic Defense Initiative (SDI), nicknamed “Star Wars.” The SDI concept: use satellites to shoot down Soviet ICBMs with lasers.
The idea never moved past the conceptual phase, but it was revived during the George W. Bush presidency as a scaled-down version that would protect the U.S. and its allies from terrorist ICBMs. That system became the GMD.
The system is strongly supported by President Trump. “Our goal is simple,” said the president when he announced the Ballistic Missile Defense Review. “To ensure that we can detect and destroy any missile launched against the United States, anywhere, any time and any place.”
But the GMD system also has its critics—in fact, the Union of Concerned Scientists doesn’t think the system actually works: “though the idea of a missile shield may sound attractive, today’s homeland system is hugely expensive, ineffective, and offers no proven capability to protect the United States—and no credible path forward for achieving success.”
The organization’s main concern is that the GMD system can’t handle countermeasures deployed by an enemy.
An ICBM could launch decoys during the midcourse phase to distract the interceptor: those lightweight decoys would follow the same trajectory as the real ICBM in space, making it hard for the interceptor to determine which is the real warhead. This could force the GMD system to use up its interceptors—there are currently only 44—before the real threats are launched.
Additionally, the ICBM could be equipped with a “cooled shroud,” which lowers the temperature of the warhead. Since interceptors rely on infrared sensors to track their targets, it would take them longer to home in on the ICBM—that is, if they see it at all.
Both of these countermeasures are within reach of countries like Russia, Iran and North Korea, which are building ICBMs. But the Pentagon has still invested over $40 billion in missile defense.
Also, while the military points to the two-shot salvo test as proof that the GMD system works, others are more skeptical about the test results.
“The simulated attacking missile’s trajectory, its exact coordinates, had to be programmed into the intercepting missile’s guidance system—an entirely unrealistic way to track an evasive drop of rain in a ballistic hurricane,” said Doug Vaughan, a defense reporter who has covered missile defense since SDI. “And for all that, they still failed more often than not.”
The test was performed on a “threat-representative ICBM”—not a real one. The U.S. military isn’t about to launch a ballistic missile at itself to test the system, so there’s no way to really tell if the system will perform successfully until someone launches an ICBM at the U.S. homeland.
While missile defense technology may have progressed since the Reagan era, its effectiveness is still in doubt—especially when conventional deterrence is doing a much more effective job at keeping the U.S. safe.
In fact, the GMD system may just be pushing U.S. adversaries to develop technologies to counter it—potentially making the system obsolete before it even gets used. Russia and China are already working on new strategic weapons to counter the interceptor. One example is hypersonic weapons technology—missiles that could move too fast for U.S. missile defense systems to intercept.
But the lack of evidence of the system’s effectiveness doesn’t seem to be slowing down the Department of Defense. The existing arsenal of 44 GMD interceptors could soon be increased, as the Pentagon has requested funding for 20 more.
“What the Pentagon is now hyping is a plan to throw ‘salvos’ of more, better, faster, smarter rocks at enemy rockets and, at best, knock down maybe 10 percent of the incoming missiles,” said Vaughan. “The other 90 percent—or even 1 percent—that get through will kill millions.”
Read more about the GMD at Boeing to Upgrade U.S. Missile Defense System.