US Navy photo by Mass Communication Specialist 2nd Class Jonathan Nye
- The US Navy has expended a lot of high-end ballistic missile interceptors in recent air defense operations.A top admiral told BI that this practice is "unsustainable" in high-tempo combat operations.Adm. James Kilby said cheaper alternatives are needed to preserve critical munitions stockpiles.
US warships fighting around the Middle East have been leaning hard on top ballistic missile interceptors. That won't be sustainable in high-tempo combat operations that can fast consume key munitions, a top Navy admiral cautioned.
Adm. James Kilby, the acting chief of naval operations, told Business Insider that cheaper alternatives for air defense are needed to preserve critical munitions stockpiles.
The Navy has regularly found itself in air defense engagements around the Middle East since a fresh wave of violence swept across the region in October 2023. In the Red Sea and the Gulf of Aden, American warships have shot down hundreds of missiles and drones that the Tehran-backed Houthi rebels in Yemen have launched at merchant shipping lanes.
And in the Eastern Mediterranean, US warships have intercepted massive Iranian ballistic missile salvos targeting Israel over three separate exchanges of fire.
Kilby said the Navy has fired "significant numbers of advanced munitions" in support of these operations. However, "while the Navy remains fully capable and ready to respond to any contingency today, the pace and volume of these high-end weapon expenditures were neither anticipated by the Navy nor the defense industrial base."
"As a result, our inventory of the most capable interceptors is reduced and requires an increased munitions delivery rate," he said.
US Navy photo
Kilby said the Navy is working with the US Missile Defense Agency, the Maritime Industrial Base Program Office, and its industry partners to expand interceptor production capacity. The efforts, he stressed, will help rebuild and sustain munitions stockpiles.
Officials and analysts have said the Navy needs more of its best interceptors for higher-level threats in the Pacific, like China and its expanding ballistic missile arsenal. Some observers have raised concerns that US warships are rapidly expending essential munitions without adequate plans to replace them.
A specific concern is the Standard Missile-3, or SM-3, interceptor inventory. These weapons can take out short- to intermediate-range missiles during the midcourse phase of flight. Unlike other ship-launched munitions, the SM-3 can engage threats in space.
US warships in the Eastern Mediterranean have used the powerful SM-3s to defend Israel from Iranian missile attacks. These interceptors, produced by Raytheon, Aerojet, and, for newer types, Mitsubishi Heavy Industries, are exceptionally effective weapons, but they come at a high price tag, between $10 million and $30 million, depending on the variant.
Another Navy ballistic missile interceptor is the roughly $4 million SM-6, suited for defense against aircraft and cruise missiles, as well as terminal defense against ballistic missile threats.
"The Navy's current reliance on high-cost interceptors, such as SM-6 and SM-3, is unsustainable in high-tempo operations," Kilby warned. He added that the military "must shift to use lower-cost alternatives while preserving expensive defenses for strategic weapons — or risk running short when it matters most."
Navy leadership has pointed to the Red Sea conflict as a clear example of the problem, as US warships have been forced to expend multimillion-dollar missiles to destroy cheap Houthi drones that can cost just thousands of dollars.
U.S. Navy photo by Mass Communication Specialist 2nd Class Jonathan Nye
Alternative options are limited for ballistic missile threats, but there are some better choices for drones that are being used to reduce pressure on interceptor arsenals.
As the Red Sea conflict dragged on, US forces increasingly found themselves relying on lower-cost alternatives to preserve the expensive missiles. During the weekslong Operation Rough Rider targeting the Houthis earlier this year, for instance, American fighter jets used cheap laser-guided rockets for around half of all Houthi drone kills.
The $25,000 AGR-20 Advanced Precision Kill Weapon System rocket is significantly cheaper than a $500,000 air-to-air missile. And these rockets are substantially cheaper than ship-launched SM-2 interceptors — weapons on the lower end of the Navy's missile defense capabilities that cost more than $2 million.
The Navy has made it a priority in its current and future operations to bring the cost difference between air defense weapons and the threats they engage much closer to parity, especially as drones become increasingly relevant in naval warfare.
Kilby said the Navy is also consistently evaluating and updating its tactics, techniques, and procedures to prepare for future operations. This includes finding ways to speed up the learning process, leading to more efficiency on the water.
For instance, Kilby said data from the Navy's advanced Aegis Weapons System — which is equipped on Arleigh Burke-class destroyers and Ticonderoga-class cruisers — previously took weeks to process after an air defense engagement. But thanks to collaboration between the sea service, industry, and tech community, that timeline has decreased to just 24 hours.
"The 24-hour assessment timeline allows our ships and weapons systems operators to improve tactical proficiency and effectiveness while remaining in combat," Kilby said.
