The US has less than a month left of advanced THAAD and PrSM ammo as it fights Iran, analysts say

• The US is on track to run out of its THAAD and PrSM munitions within weeks, three researchers said.
• Their estimates came from analyzing the first 16 days of the US-Israeli war with Iran.
• They estimated that over 11,000 total munitions were fired by the US and its allies in that period.

US stockpiles of advanced air defense interceptors and ground-attack missiles will run dry in weeks if the fighting pace with Iran continues, three analysts have warned.

Their commentary, published on Tuesday by the UK-based think tank Royal United Services Institute, indicated that the US would have depleted its Terminal High Altitude Area Defense, or THAAD, interceptors by April 17.

Munitions stockpiles for its Army Tactical Missile Systems and Precision Strike Missile, or ATACMS and PrSM, would run out more quickly, by April 12, they said.

The three analysts — independent researcher MacDonald Amoah and The Payne Institute of Public Policy's Morgan D. Bazilian and Lt. Col. Jahara Matisek — projected a more dire situation for Israel's Arrow 2 and Arrow 3 anti-ballistic missile stockpiles. Those would last only until Friday, they estimated.

"While the war could proceed with other munitions, this implies accepting greater risk for aircraft and tolerating more missile and drone 'leakers' damaging forces and infrastructure," the analysis said.

Such stockpiles have long been a concern for the US, with fears that depleting them would undermine the Pentagon's ability to maintain deterrence in other theaters, such as the Indo-Pacific.

The THAAD is considered one of the best missile defense systems in the world, with the touted rare ability to intercept long-range ballistic missiles and other threats inside Earth's atmosphere.

Two to three of these US-operated batteries are believed to be in the Middle East, out of a total of five known to be deployed outside the continental US. Their interceptors can cost up to $15 million each.

Meanwhile, the ATACMS and the PrSM are precise, ground-launched missiles for striking other ground targets more than 180 miles away.

The PrSM is a newer munition, intended to eventually replace ATACMS, and made its combat debut in the Iran war. Defense Department records show that the US has manufactured at least 328 of these missiles in the last two years, with another 124 planned for this year.

"Our analysis shows that the coalition can continue fighting Iran, but with increased risk to forces in-theatre," the analysts wrote. "The bigger risk, however, is what continued fighting against Iran does to deterrence and defence elsewhere."

The Pentagon did not immediately respond to a request for comment sent outside regular business hours by Business Insider.

Replacing 11,000 munitions

Overall, the researchers said they tracked the US and its allies in the Middle East expending 11,294 munitions in the initial 16 days of the war. Roughly 5,000 of these — both for offensive strikes and air defense — were fired in the first four days of the conflict, they said.

When it comes to air defense, Iran's retaliatory drone and missile attacks have since dropped sharply. After the war's first four days, Gen. Dan Caine, the chairman of the Joint Chiefs of Staff, said ballistic missile launches and drone attacks plunged 86% and 73%, respectively.

The researchers said they tracked a daily average of 33 Iranian missile attacks and 94 drone strikes after the initial drop. And defeating one of these threats can take multiple munitions.

"Given that Iran has damaged at least a dozen US and allied radars and satellite terminals, the efficiency of interception decreases; using 10 or 11 interceptors for one missile or 8 Patriot missiles for one drone becomes unsustainable," the researchers wrote.

They especially warned of challenges the US faces in its defense industrial base and rare-metal supply when replenishing those stocks. If the US wants to do so at speed, the total bill so far is likely to reach $50 billion, they said.

As an example, the trio estimated that the US fired more than 500 Tomahawk missiles against Iran, saying they would take "at least five years" to replace.

Meanwhile, restocking the roughly half a million 20mm rounds fired from air defense systems during the war also requires about 8,800 pounds of tungsten, they added. China is known to control over 80% of the global supply of the metal.

Besides recommending that the US invest heavily in its industrial base, the researchers urged building a "patchwork shield" by layering cheaper and more advanced air defenses that can be mixed and matched on the fly.

"Command of the commons remains necessary, but Epic Fury demonstrates it is increasingly insufficient without 'Command of the Reload,'" they wrote.