Waves of quadcopters crashed out of the sky in Indiana earlier this week during a military demonstration. Their sudden, synchronized collapse wasn’t the result of missiles or shrapnel. It came from an invisible beam of energy.

At Camp Atterbury, a defense contractor called Epirus staged a demonstration of its high-powered microwave (HPM) weapon, Leonidas. Before a crowd of U.S. military officials and allied nations — some from the Indo-Pacific — the company staged a two-hour show. In the climax, the Leonidas system took out 49 drones at once.

Epirus CEO Andy Lowery was ebullient. “I call this a singularity event.”

He also argued the tech belongs far beyond battlefields: “This platform is going to be needed at stadiums and at ports and at airports,” he told Axios. “The list goes on and on.”

The Drone Swarm Problem

Drone swarms are here. In Ukraine, quadcopters drop explosives into trenches. In the Red Sea, the Houthis have used drone boats and flying drones to strike at cargo ships and even at faraway Israel. Even American bases have seen fatal attacks from cheap drones that cost a fraction of the missiles used to stop them.

That asymmetry keeps U.S. planners up at night. “I’m hesitant to say it out loud so I don’t manifest it,” admitted Alex Miller, the Army’s chief technology officer, during an interview with MIT Tech Review. He imagines a nightmare scenario in which tens of thousands of autonomous drones descend on bases in the Pacific in a surprise attack, overwhelming defenses in a matter of hours.

Traditional weapons can’t keep up. Missiles are effective but costly. Lasers must track one target at a time. Interceptor drones and nets can only manage so many. Even electronic jammers are faltering as drones evolve to fly autonomously, free of GPS or radio links. For instance, for nearly a year, the battlefield in Ukraine has been littered with thousands of kilometers of fiber optic wire, employed by drones that are impossible to disable with electronic warfare.

“Unjammable” doesn’t mean “unzappable,” however — and that’s where Leonidas enters the picture.

Inside the Microwave Weapon

Leonidas doesn’t fire bullets, rockets, or laser pulses. It projects invisible waves of energy that seep into a drone’s electronics. A motor controller shorts. A circuit board fries. Ultimately, the drone stalls and falls.

The machine itself resembles a slab of metal the size of a garage door, mounted on a trailer. Behind the panel sit dozens of amplifiers made from gallium nitride, a semiconductor that tolerates extreme voltages and heat. Software controls the array, shaping and steering the microwave beam with precision. Instead of physically swiveling a turret, the system can flick between targets — or sweep across many — at the speed of computing.

Engineers at Epirus’s Torrance, California headquarters test the technology inside foam-padded chambers, zapping drones under controlled conditions. “Sometimes if we rotate the drone 90 degrees, you have a different motor go down first,” explained Tyler Miller, a senior systems engineer. No matter the angle, the microwaves find a way in. Even copper shielding can’t save a drone when antennas, propeller shafts, and seams leave tiny openings for energy to slip through.

What makes the system striking is scale. Leonidas can bathe a wide arc — roughly 60 degrees — with power, striking multiple drones simultaneously. And unlike a missile battery, it never runs out of ammunition. As long as it has power, it can keep zapping.

From Battlefields to the Fleet

The Army has already invested heavily. In 2023 it awarded Epirus a $66 million contract, followed by another $17 million in the fall. Leonidas units are now in the field for evaluation, including a live-fire exercise in the Philippines. Senior officers have signaled confidence, even as they caution that work remains to integrate the weapon into broader “kill chains” alongside sensors and kinetic systems.

The Navy, too, has claimed a version of the technology. Through the Office of Naval Research, Epirus developed ExDECS — the Expeditionary Directed Energy Counter-Swarm system — tailored for Marines and naval warfare. Delivered to the Naval Surface Warfare Center Dahlgren in Virginia, the prototype is being tested against threats ranging from aerial drones to explosive-laden surface vessels. In pier-side trials, engineers used the microwaves to disable the outboard motors of drone boats, the kind Houthis have launched in the Red Sea.

“Drone warfare is changing the fight — fast,” Lowery said when announcing the Navy delivery. “Systems like ExDECS give Marines a decisive advantage by neutralizing multiple electronic threats at once with a single system — what we call a one-to-many capability.”

What Comes Next

The rise of microwave weapons is part of a larger shift in the defense industry. Venture-backed firms like Epirus and Anduril are pitching systems on faster timelines, raising private capital to build first and seek contracts later. Epirus has already raised half a billion dollars, including $250 million earlier this year, to prepare for scaled manufacturing.

The stakes are high. China has already displayed its own high-powered microwave system, dubbed Hurricane. If both sides embrace the technology, invisible beams may become as common on future battlefields as artillery and missiles are today.

Military planners are bracing for that possibility. “Counter-UAS [Unmanned Aircraft System] unfortunately is going to be like counter-IED,” Miller said. “It’s going to be every soldier’s job to think about UAS threats the same way it was to think about IEDs.”

Epirus, meanwhile, is thinking bigger. Engineers are building smaller Leonidas versions that can mount on Stryker combat vehicles or even airborne drones. Lowery has floated the idea of massive, city-scale installations — fixed emitters that could project force fields over entire skylines.

He leans into mythology when describing the mission. Drones, he says, are “like Icarus, with his wax wings. Flying all around—‘Nobody’s going to touch me, nobody’s going to ever hurt me.’”

Then he adds, with a grin: “We built one hell of a wax-wing melter.”