Watch a U.S. Navy Destroyer Shoot an ICBM Out of the Air During a Test

The U.S. Missile Defense Agency (MDA) said it successfully shot an ICBM out of the air during a test of the Aegis Ballistic Missile Defense system. The implication of the test is that America could use missiles to knock incoming nukes out of the air should a rival country, North Korea say, launch one at the U.S. or its allies. The truth about missile defense is more complicated.

Ten minutes shy of one A.M. on Tuesday morning, a test side in the Marshall Islands launched a mock ICBM toward the ocean off the coast of Hawaii. The U.S.S. John Finn launched a missile from its Aegis system which intercepted the mock ICBM and destroyed it. "This was an incredible accomplishment and critical milestone for the Aegis" Vice Admiral Jon Hill, MDA director said in a press release. “We have demonstrated that an Aegis BMD-equipped vessel equipped with the SM-3 Block IIA missile can defeat an ICBM-class target, which is a step in the process of determining its feasibility as part of an architecture for layered defense of the homeland.”

The Aegis system is just one part of America’s vast missile defense network. The idea behind its various programs is that the U.S. can use satellites to detect and track incoming nuclear threats and then knock them out of the sky with its own missiles. It’s a system that, thankfully, has never been put to the test with a real incoming missile. The Aegis system completing this test is a big deal because missile defense systems mostly fail when tested.

According to the Union of Concerned Scientists, a nonprofit science advocacy group, missile defense systems fail roughly 60 percent of the time during tests. This particular anti-ICBM missile, Raytheon’s SM-3 Block IIA, has failed in six previous tests. During a 2017 test, a Sailor accidentally marked the targeted ICBM as a friendly missile. To avoid friendly fire, the SM-3 self-destructed. A year later, another test of the SM-3 failed.

The Union of Concerned Scientists has done extensive studies of the ground based missiles defense system tests, showing all the ways they fall short of simulating a real world scenario. Often in these tests, the decoy moves slower than a real ICBM would, burns brighter, or displays other characteristics that lend the missile defense systems an unrealistic advantage.

The bigger story—according to Laura Grego, Senior Scientist in the Global Security Program at the Union of Concerned Scientists—is what a test of the Aegis signals to Russia and China. 

“Plans call for deploying hundreds of these new interceptors on mobile, globally-deployable Aegis BMD ships,” Grego said on Twitter. “The dramatic expansion of strategic defense cannot escape the notice of Russia and China. It is likely to have a crushing effect on prospects for new nuclear arms control agreements and will also provide motivation (or justification) for Russia and China to diversify and grow their nuclear arsenals.”

The old existing nuclear arms treaties are falling apart. New START, an Obama era treaty limiting the number of deployed warheads in Russia and the United States, will expire in February unless it is renewed. Joe Biden has signaled that he’ll renew the treaty, but it’s possible that Trump and his team poisoned that well.

Meanwhile, Russia has been developing new nuclear weapons with the goal of circumventing U.S. missile defense systems like the Aegis. Hypersonic reentry glide vehicles in particular are supposed to beat missile defense systems by being both maneuverable and fast, making it hard for the defense system’s computers to lock in on the target. China has developed its own hypersonic missile.

The theory behind nuclear weapons is deterrence, the idea that no country would attack another nuclear armed nation for fear of nuclear retaliation. But deterrence only works when the threat of nuclear attack is credible, which has created a situation where Russia, China, and the U.S. develop intricate systems of defense and destruction. There’s no way to tell how well any of these weapons or defenses would work until they’re used in the real world and if that happens, the effectiveness of the Aegis system will be the least of our worries.