To produce the SM-6 starting in the early 2000s, Raytheon and the US Navy took the airframe of the SM-2, added the newer SM-3’s rocket booster, plugged on the seeker from the beyond-visual-range AMRAAM air-to-air missile and also added GPS.
The resulting weapon can target missiles and aircraft in the air, ships at sea and targets on land. It’s one of the few truly omnirole missiles in the American arsenal – and the US forces are finding more and more new applications for it.
At first, SM-6s only armed warships – and only engaged targets in the air. The Navy expanded the missile’s target set to include ships at sea and targets on land. More recently, the US Army adopted the missile – and stood up new SM-6-armed missile batteries whose main mission is attacking targets on land from land.
Now the SM-6 seems to be heading into the air. In 2021, an F/A-18F fighter belonging to a US Navy test squadron was photographed carrying an inert SM-6 – missing its first-stage rocket booster – over a California test range.
That 2021 test apparently supported Raytheon and the US Navy’s effort to develop a new very-long-range air-to-air missile. Three years later in April, another US Navy F/A-18 appeared over the same California test range carrying a possible live SM-6.
Clearly, Raytheon and the US Navy are still developing the SM-6 for possible airborne launch. The benefits are obvious. The 3,300-pound SM-6 ranges as far as 230 miles – that’s probably more than twice as far as the US Navy’s current long-range air-to-air missile, the AMRAAM.
As an anti-ship or land-attack missile, the SM-6 also has advantages over the US Navy’s existing aerial munitions. With its Mach-3.5 top speed, it’s much faster than the current Harpoon anti-ship missile and Joint Air-to-Surface Standoff Missile land-attack weapon, both of which are subsonic. A faster missile is harder to intercept.
The SM-6 is also desirable as it is assessed as having at least some capability to knock down inbound hypersonic weapons, often considered impossible to defend against. This would be an important mission no matter what an SM-6 was launched from: but the US Navy would be particularly glad to have SM-6s on its defending fighters as well as its escorting destroyers, in the event of Chinese or Russian hypersonics being fired at a US aircraft carrier.
Perhaps most importantly of all, the SM-6 switches modes with the press of a few buttons. An F/A-18 fighter hauling a clutch of SM-6s could wait for targets to appear in the air, at sea or on land – and attack any or all of them with the same munitions. No need to land and re-arm.
If there’s a problem with the SM-6, it’s that the high-tech missile is expensive. Each 22-foot round costs more than $4 million – and that weighs on the production rate. In the first 15 or so years of procurement, the US fleet built up a stockpile of around a thousand SM-6s. More lately, it’s been acquiring fresh missiles at a rate of 125 a year.
This is far too few missiles. The US Navy’s destroyers and cruisers have thousands of missile cells between them. If the US fleet also armed its hundreds of F/A-18s with SM-6s, it would create far more demand for missiles than its limited inventory – and anaemic production rate – could satisfy.
It’s possible to imagine that, in a major war with China, American ships and planes – to say nothing of those US Army batteries on land – would fire off every SM-6 ever produced in the span of just a few days.
Arguably, the US Navy’s top priority shouldn’t be adding launch platforms for its best missile but, instead, adding missiles to the existing launchers. “More precision-guided munitions will be necessary for a high-end conflict,” Montgomery wrote. “Should China decide to invade Taiwan before the end of the decade, the Navy will have insufficient stocks of high-value munitions at the start of conflict. Time is of the essence.”