The US Navy has now proven it can stop ballistic missiles

USS Lake Erie launches a Standard Missile 3 (SM-3) interceptor at a non-functioning US spy satellite orbiting above the Pacific Ocean in 2008. The SM-3 successfully destroyed the satellite, and has now been used successfully in combat against Iranian ballistic missiles – US Navy/Getty

When Iran launched waves of drones and missiles at Israel on Saturday, the US military deployed warships and warplanes to reinforce Israeli and allied defences. American forces actually shot down more of the roughly 160 drones and missiles than Israeli forces did, according to The Intercept.

The US Navy’s surface fleet contribution was a pair of destroyers, USS Arleigh Burke and USS Carney. Between them, the two 500-foot destroyers shot down as many as seven Iranian ballistic missiles. What’s most notable is how the ships shot down the missiles.

As reported by Sam Lagrone at USNI News, they fired Standard Missile-3 (SM-3) interceptors: 22-foot missiles with rocket boosters. SM-3s don’t carry normal explosive warheads but “exo-atmospheric kill vehicles”, EKVs, designed to destroy targets travelling at immense velocities beyond the Earth’s atmosphere in space. The $12-million-a-shot SM-3s are the Navy’s premier ballistic-missile-defence munitions, and the only ones the service has which can potentially bring down a ballistic weapon during the “mid course” phase of its flight, while it is outside the atmosphere. SM-3s had never been fired in combat before Saturday, though an SM-3 was used operationally in 2008 to destroy a malfunctioning US spy satellite in low orbit.

The Navy and the US Missile Defence Agency have been testing and improving the SM-3 for decades. But despite plenty of successful test shots, no one knew for sure whether the SM-3 would work in the stress of actual combat.

Good news for American missile-defence planners. The SM-3 works. And that has big implications for US forces as they plan for a possible war with China.

Not only is the American fleet counting on destroyers and cruisers armed with SM-3s to protect aircraft carriers and amphibious ships from the biggest and most dangerous Chinese ballistic missiles, US forces on the island of Guam – one of America’s main Pacific outposts – plan to include the SM-3 in a new missile-defence system for the island.

The SM-3’s EKV payload is unusual. It doesn’t explode, but rather destroys targets by hovering precisely in their way and letting them collide with it, wrecking themselves as much or more by their own kinetic energy as that of the EKV. The key is an extremely sensitive infrared telescope that tracks a hot ballistic warhead in the cold near-vacuum of the “exo-atmosphere” – the beginning of space, 60 miles up and more.

The exquisite technology explains the SM-3’s high cost. It also explains why it has taken the Navy so long to develop and deploy the SM-3 – and to finally fire it in combat for the first time.

The fleet was betting big that the missile would work. It’s modifying more than 50 ships to launch SM-3s. Two land-based sites in Poland and Romania have SM-3s. The Navy has already bought around 500 missiles, and buys several dozen more every year.

Whenever the Navy deploys an aircraft carrier, it also sends along a cruiser and destroyers armed with SM-3s. Another 11 destroyers hang around in US waters, ready to sail to global hotspots on short notice. Nine destroyers sail from Japan for patrols around China. Another four operate out of Spain in order to be within easy reach of war zones around the Mediterranean Sea.

That’s an awful lot of infrastructure for a missile that, until last weekend, lacked much real-world validation. And the infrastructure is only growing. Keenly aware of the growing threat North Korean and Chinese ballistic missiles pose to bases in Guam, the Pentagon gave the Navy a 2026 deadline to reinforce the island’s defences.

There’s already a US Army Terminal High Altitude Area Defence System surface-to-air missile battery on Guam. The Army will add a Patriot battery while the Navy contributes mobile launchers for SM-3s and lower-altitude SM-6s. Meanwhile, just three days ago the Army also deployed its “Typhon” missile system, able to launch SM-6s, to the Philippines. An Army command-and-control network will tie together the launchers and their associated radars.

Japan is also, understandably, very concerned about North Korean and Chinese ballistics, and it too has destroyers armed with SM-3s. South Korean warships are suitable to carry SM-3s too, and that nation’s government is upgrading its fleet to do so. Some Australian warships could be armed with SM-3 in future. A network of ballistic defences is spreading among US allies in the Pacific.

Army and Navy missiles will defend Guam from cruise missiles, non-nuclear ballistic missiles and potentially even maneuvering hypersonic missiles: the SM-6 is thought to have at least some capability against hypersonics. All that is to say, the SM-3 is only becoming more and more important to US war plans.

And this trend is, if anything, accelerating as the Navy tries to wring every ounce of possible performance from the SM-3’s basic design. The latest version of the missile, the heavier and pricier Block IIA, might even be able to intercept nuclear-tipped intercontinental ballistic missiles – at least in the lower, beginning and ending, parts of their flight through space.

A 2020 test of the Block IIA against an ICBM-like target, was inconclusive. Yes, the missile hit the target. But the Missile Defence Agency deliberately dumbed down the target: it lacked the extreme high speed and self-defence measures – decoys, for example – of a real ICBM.

Still, the Pentagon and the Navy were increasingly confident in the SM-3’s capabilities before a handful of the missile arced into the sky to collide with Iranian missiles streaking toward Israel on Saturday. And they’re surely even more confident now.

It took a long time and billions of dollars, but the American fleet now has a battle-proven ballistic missile interceptor.

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