U.S. Army’s $43.5M Leonidas II Deal: Defeating Autonomous and Cable-Controlled Drones

The U.S. Army's Rapid Capabilities and Critical Technologies Office (RCCTO) has awarded Epirus a $43.5 million contract for the delivery of two Leonidas High-Power Microwave (HPM) Generation II systems. This procurement reflects a strategic move to enhance the Army’s Integrated Fires Protection Capability (IFPC) against evolving aerial threats, particularly unmanned aerial systems (UAS), which have become increasingly prevalent in modern conflict zones and domestic security scenarios.

Leonidas II Microwave Weapons. Photo: Epirus

The Leonidas Generation II systems are designed to address the limitations observed in earlier prototypes and incorporate feedback from operational testing. These systems are expected to significantly expand the effective range—more than doubling that of the Generation I models—and increase power output by approximately 30 percent. The upgrades include high-density batteries for extended operational time, reduced reliance on external power sources, and advanced waveform and polarization techniques to improve engagement against a broader spectrum of targets. Additionally, the systems feature extra-long pulse widths and a high-duty burst mode to facilitate rapid multi-target engagement.

Leonidas operates by emitting long-pulse microwave energy across multiple frequency bands, creating an electromagnetic interference field capable of disrupting the electronics of drones and other airborne threats. Unlike traditional kinetic systems, which rely on physical projectiles, Leonidas uses directed energy to neutralize threats without the need for reloading or sustained mechanical operation. This approach offers a cost-efficient alternative to conventional missile-based air defense, particularly in scenarios involving drone swarms or autonomous systems that are resistant to jamming.

The system’s modular architecture, built around Line-Replaceable Amplifier Modules (LRAMs), allows for scalability and adaptability across various platforms. Leonidas can be mounted on vehicles such as the Stryker or integrated into mobile and expeditionary configurations, including the Leonidas Pod and Leonidas H₂O variants. These adaptations enable deployment in diverse operational environments, from forward operating bases to maritime interdiction zones.

In terms of effectiveness, Leonidas has demonstrated the ability to disable multiple drones simultaneously, including those operating autonomously or using fiber-optic guidance. This capability is particularly relevant given recent incidents involving drone incursions over military installations and critical infrastructure. The system’s ability to maintain a persistent electromagnetic field—rather than relying on short, high-intensity pulses—allows it to disrupt targets over extended periods, increasing the likelihood of successful neutralization.

Leonidas Generation II disables autonomous drones by targeting their internal electronics rather than relying on disrupting external control signals. Autonomous drones, which operate independently of remote commands, are typically immune to traditional jamming techniques. Leonidas counters this by emitting sustained high-power microwave (HPM) energy across a broad frequency spectrum, creating an electromagnetic interference field that overwhelms the drone’s onboard systems. This field disrupts microprocessors, navigation modules, and sensor arrays, causing the drone to lose functionality and crash. The system’s long-pulse duration—extending up to a millisecond—ensures prolonged exposure, increasing the likelihood of disabling hardened or shielded electronics even in drones designed to resist electronic warfare.

Fiber-optic cable drones, which are physically tethered to ground stations via optical cables, present a unique challenge due to their immunity to radio frequency jamming. These drones transmit control and data signals through light pulses, making them undetectable to RF-based countermeasures. Leonidas neutralizes these threats by bypassing the communication link and directly attacking the drone’s internal electronics. The HPM field penetrates the drone’s casing and interferes with its operational circuitry, regardless of how it receives commands. This capability allows Leonidas to disable drones that would otherwise evade conventional defenses, including those used in high-security or covert operations.

However, the deployment of HPM systems like Leonidas is not without challenges. Environmental factors such as weather conditions, terrain, and electromagnetic interference from friendly systems can affect performance. Additionally, integration with existing command-and-control networks and ensuring interoperability with other defense assets require careful planning and testing. The Army has scheduled evaluations at Naval Air Weapons Station China Lake to assess cooperative fires capability and other engineering metrics.

Leonidas is envisioned as a component within a layered defense architecture, complementing kinetic systems such as cannon-based weapons and missile interceptors, as well as other directed energy platforms like lasers. Its role is to provide a non-kinetic option for short-range air defense, particularly in scenarios where rapid response and minimal collateral damage are priorities. Collaboration with systems like the Lattice C2, developed by Anduril Industries, enhances Leonidas’ ability to detect, track, and classify threats using artificial intelligence and machine learning.

The broader strategic implications of this procurement extend beyond immediate battlefield applications. The Army’s interest in Leonidas reflects a shift toward energy-based solutions for homeland defense, border security, and protection of high-profile events. Potential future deployments may include installations near critical infrastructure or venues hosting international gatherings, where the risk of drone-based attacks is elevated.

The acquisition of Leonidas Generation II systems represents a significant investment in directed energy capabilities by the U.S. Army. While the technology offers promising advantages in terms of cost, scalability, and operational flexibility, its integration into existing defense frameworks will require continued testing and refinement. The success of these systems could influence future procurement decisions and shape the evolution of air defense strategies in an era increasingly defined by unmanned and autonomous threats.