While the U.S. conflict with Iran is on hold, some military experts and members of Congress are concerned about how quickly American forces burned through expensive munitions and how long it could take to replace those stockpiles. 

Over 39 days, more than half of the American stockpiles of critical defensive munitions used to intercept other missiles, known as Patriot and THAAD missiles have been used, according to an analysis by the Center for Strategic and International Studies.

It takes four years to make a Patriot missile and a bit longer than that to deliver a THAAD, or Terminal High Altitude Area Defense missile, to the DOD, the center said. 

Each individual missile is also costly. One THAAD missile costs $15.5 million and the price tag for one Patriot missile is $3.9 million. At least some of these munitions brought down drones worth only tens of thousands of dollars.

The center analyzed seven types of munitions, including Tomahawk missiles, and found high rates of use in every category, but enough to continue a fight with Iran. 

When it comes to using the interceptors against drones, members of Congress recently asked for a better, more cost-effective solution to bring down drones.

U.S. Rep. Betty McCollum, D-Minn., told Army Acting Chief of Staff Christopher LeNeve and Army Secretary Dan Driscoll about her concerns last week. 

“We must come up with a better solution for taking out drones. Using Patriot missiles that cost $3 million each is not cost-effective, and it’s not sustainable,” she said.  

Driscoll said the Army has already invested in Perennial Autonomy’s Merops, a system that relies on small drones that fit in a backpack to bring down the larger Shahed drones that are about 8 feet across. 

The Associated Press first reported the Merops system was sent from Ukraine to the Middle East in March. The drones also rely on AI to navigate when electronic communications are jammed, AP reported. 

Each Merop drone is about $15,000, Driscoll said, lower than the cost of a Shahed. 

“That puts us on the right end of the cost curve,” he said. 

To take down drones there are other options, as well, said professor Iain Boyd, director of the Center for National Security Initiatives at the University of Colorado Boulder, including lasers and perhaps high-powered microwave weapons.

The Army has fielded a few high-energy laser weapons on Stryker vehicles and, in terms of cost per shot, they offered the cheapest solution. Each shot cost $12, Breaking Defense reported. Lockheed Martin also has developed a laser-based weapon for the Navy, called HELIOS or High Energy Laser with Integrated Optical-dazzler and Surveillance, for use on ships.   

The “magazine” on a laser could be considered infinite, Boyd said. Although sometimes they have to cool down.  

“As long as you got your laser plugged into an electrical power source, you can keep on firing,” he explained. 

But you have to put a hole in each drone, while a directed high-power microwave could fry the electronics of a drone swarm in one sweep, he said. But they are not as far along in development as lasers.  

“Lasers are now. Microwaves are the next thing,” he said.

But missiles will remain a significant threat, and so the U.S. needs to rebuild its stockpiles of interceptors, an effort that will take a significant investment of time and money, Boyd said. But that’s not the only worry. 

“The bigger question is, ‘how does that leave the U.S. in terms of the other engagements it might want to have or need to have?’” he said. 

The high rate of U.S. munitions’ use in Iran could present an opening for a near-peer aggressor like China, he said.  

“That’s the thing I think is the biggest deal,” he said. 

As part of the effort to rebuild the military, the Trump administration is proposing a record $1.5 trillion investment into the Department of Defense in 2027 and anticipates over half will go into new capabilities. The budget sets aside $74 billion for “drone dominance.”

The investments will need to take into account the huge barrages of missiles and drones that the U.S. has already seen from Iran.

The barrages are tough, in part because they have to be tracked differently.

Missiles can be tracked from a satellite using infrared sensors, because they are hot and many are on a set trajectory. Drones are relatively cool and typically are tracked via radar.

Managing barrages probably will take AI to help prioritize the munitions posing the largest threat and building trust in those systems, Boyd said.  

“It is the numbers, but it’s also the diversity of threats and the way those threats operate,” Boyd said.