Editor’s Brief¹

Last Week we looked at Shield AI and the challenges of building autonomous systems that can be trusted in combat. To jump deeper into the hazards of AI, consider reading Missy Cummings' article, "A Taxonomy for AI Hazard Analysis."

This week, we’re back on defense.

As the DoD confronts the rising cost of missile-based defense, a sharper question is emerging:
How do you defend against low-cost threats—without running out of ammo?

Epirus is one of the companies at the center of that answer.

Signal Brief: Epirus - How the Magazine Problem is Reshaping U.S. Air Defense

Epirus is redefining air defense with solid-state, energy-based high-power microwave (HPM) systems. At the center of this breakthrough is Leonidas—a cutting-edge HPM platform that has evolved into a family of scalable counter-electronics systems. Epirus is best known for tackling one of a large vulnerabilities: the proliferation of low-cost drone swarms capable of overwhelming traditional defenses.

Origins & Vision

Founded in 2018 by a team of former defense engineers and tech entrepreneurs—including Nathan Mintz (Raytheon, Boeing), Dr. Bo Marr (DARPA, Raytheon), Max Mednik (Google ML), and investor Joe Lonsdale (8VC Founder, Palantir Co-Founder)—Epirus’ goal was to create a scalable solution to the growing threat of drone swarms.

At the time, high-power microwave systems were massive, expensive, and fragile. Epirus flipped the script by developing a scalable, solid-state, energy-based high-power microwave technology platform. 

The company proved its approach in January 2023, winning a U.S. Army contract after outperforming several prime contractors in an Army-sponsored competitive shoot-off. All four systems were then delivered in just 14 months.

From the outset, Epirus’ mission has been to “overcome the asymmetric challenges inherent to the future of national security.” The company name is inspired by the mythical bow of Epirus, wielded by King Theseus, which held an infinite cache of arrows. Leonidas carries this lineage forward as a directed-energy platform with an effectively unlimited magazine.

Key Takeaways

• One-to-Many Mindset: Leonidas is a one-to-many technology that creates an electromagnetic "force field" capable of neutralizing multiple drones and electronic threats simultaneously. 

• Unlimited Magazine depth: Epirus’ HPM systems run off small generators, so they operate at the cost of electricity and can deliver sustained effects during attacks

• Solid-State Revolution: Replacing traditional vacuum tubes with GaN semiconductors enables dramatic reductions in size, weight, and power (SWaP) requirements.

• Defense-Grade Interoperability: Epirus built Leonidas with an open architecture to plug into existing military networks.

• Battlefield-Ready Validation: Army testing demonstrated 100% effectiveness against all drone targets during Engineering Developmental Testing. Their technology was also validated against boat motors in recent U.S. Navy-sponsored testing. 

• Investor Confidence & Traction: Epirus has attracted over $550 million in funding with the company’s valuation exceeding $1 billion.

Tech Radar:

Leonidas – Counter-Electronics Force Field

Leonidas, Epirus' flagship platform, evolved from a tech demonstrator into a field-proven counter-UAS system.  It neutralizes electronic threats by disabling guidance systems, motors, and control circuitry. The Leonidas Family Portfolio also includes:

• Mobile: Vehicle-mounted variant integrated onto the Stryker combat vehicle in partnership with General Dynamics Land Systems, providing mobile protection.

• Pod: Miniaturized, lightweight version designed for integration onto airborne platforms or for highly mobile ground applications

• Expeditionary: Compact variant supporting Marine Corps Expeditionary Advanced Base Operations, fitting on a JLTV trailer.

• H2O: Maritime-focused variant capable of disabling outboard motors on small vessels.

Key Capabilities

• Power-Management Technology: Optimizes microwave emission, maximizing effectiveness while managing thermal challenges.

• Digital Beamforming: Software-controlled targeting that creates "no-fly zones" while permitting friendly UAS operations.

• Open Architecture Integration: Interfaces with existing military networks including for integration into layered defense.

• Line-Replaceable Amplifier Modules (LRAMs): Modular components enable field maintenance in under eight minutes and graceful degradation if damaged.

• Non-Kinetic Engagement: Creates no debris, requires no reload, and poses minimal collateral damage risk compared to missiles or guns.

One of Epirus’s most important innovations is power management. Its proprietary AI-driven system precisely controls GaN semiconductors, addressing the thermal and power density challenges that have been major issues in traditional HPM systems.

Epirus highlights that, unlike legacy systems focused on peak power, Leonidas takes an energy-based approach—prioritizing duration of effect and cumulative energy on target. Combined with advanced waveform generation, this allows for more efficient electronic disruption and improved SWaP performance

Market Signals

Funding & Growth

• Total Funding: $550+ million across 4 rounds

• Latest Round: $250M Series D (March 2025) co-led by 8VC and Washington Harbour Partners

• Notable Investors: 8VC (Joe Lonsdale), General Dynamics Land Systems, T. Rowe Price, Bedrock Capital, StepStone Group

• Valuation: $1.35 billion (2022 Series C)

• Annual Contract Value Growth: $0 in 2019 → $5.5M in 2022 → $66.1M in 2023 → $83.1M+ in 2024

Epirus plans to use recent funds to “hyperscale” production, strengthen its supply chain, and expand into international and commercial markets.  They also plan to establish a new training/simulation center in Oklahoma to help operators learn counter-UAS warfare.

Contracts & Government Traction

Epirus has secured multiple defense contracts, including:

• Peraton Strategic Teaming (Feb 2025): Supporting a $48B-ceiling IDIQ with the Air Force.

• IFPC-HPM Program - $66.1M Army contract for four Leonidas systems (delivered Nov 2023–Mar 2024). 

  • The U.S. Army issued a notice of intent to sole source Integrated Fires Protection Capability-HPM Gen II in October 2024. Gen II will offer, “increase[d] effective range through increased peak power and configurable polarization; lethality through waveform advancements; reliability, maintainability, and safety based on soldier feedback on Generation I.”

• ExDECS Program - $5.5 million OTA in August 2022 from ONR/MCWL/JCO for expeditionary counter-swarm capability.

• Early R&D - Multiple DARPA contracts and SBIR grants from Air Force and Navy in 2019-2021 for foundational HPM research.

Epirus has successfully integrated its systems with the U.S. Army’s FAAD C2 as well as platforms from Droneshield, Anduril, and General Dynamics Land Systems.

The Department of Defense has steadily increased investment in directed energy technologies, with over $430 million budgeted for FY2025 and a projected $2.3 billion committed across the FYDP. While most of this funding supports RDT&E, it reflects a continued interest in non-lethal capabilities.  Epirus stands out in this landscape as one of the few companies with HPM systems already delivered actively integrated into service architectures.²

Looking Ahead

In 1944, the U.S. Navy learned a brutal lesson at Leyte Gulf: massed, low-cost threats can overwhelm even the most advanced fleet. Kamikaze pilots sank 34 ships and damaged hundreds more.

Eighty years later, that lesson is back. In the Red Sea, $2,000 Houthi drones are forcing million-dollar responses. Each intercept takes ~1.3 missiles, driving per-engagement costs to $2.6–$5.2 million. Even “cheaper”air-to-air interceptors like the AIM-9X ($400,000–$900,000) and AIM-120 ($1 million) struggle to close the cost-exchange gap.³

Now scale that to a full swarm targeting a U.S. warship or base. The uncomfortable reality: our current magazine depth likely can’t keep up.

U.S. missile stockpiles are being depleted faster than they can be replenished. Ukraine, Israel, and Middle East operations are stretching the industrial base thin. War games warn the U.S. could burn through 5,000+ missiles within weeks of a high-end conflict with China.

The Pentagon is paying attention. Acting CNO Admiral James Kilby put it bluntly: “We certainly need more depth of magazine if we’re going to get into a protracted conflict.”

This is where Epirus fits. Leonidas is a one-to-many system that disables entire swarms with a single pulse. No reloads. No warheads. No logistical tail of resupply aircraft and shipping containers. Just fast, precise, persistent effects—delivered at the speed of light.

In a world of shrinking stockpiles and rising threat density, Leonidas doesn’t just save money. It saves options. It keeps interceptors in reserve. It buys time, space, and survivability.

So, the question isn't whether we need missiles.
It's whether we can afford to keep using them.

Challenges

• Thermal Stability – Maintaining consistent performance under harsh operational conditions both ashore and at sea

• Supply Chain Risk – Scaling GaN production requires precision manufacturing and rare components

• Kill Web Integration – Impact depends on seamless networking with Army, Navy, and Marine Corps C2 systems.

• Competiting Priorities – Must prove superiority over lasers, interceptors, and hybrid C-UAS platforms. 

Bottom Line:

For decades, high-power microwave weapons were too large, too unstable, and too fragile to deploy. But Epirus turned a fringe capability into a scalable, reload-free, cost-effective layer of defense when magazines run low and threats keep coming.

If Leonidas proves out in CENTCOM and transitions into broader service use, it could become a foundational piece of how the U.S. preserves firepower, sustains presence, and adapts to the economics of modern warfare

But it’s not a silver bullet. And yet, it doesn’t need to be.

Because the next fight won’t just be won by having the better missiles. It’ll be won by having enough left when the next wave comes.

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1  The views expressed in this newsletter are my own and do not represent the views of the U.S. Navy, Department of Defense, or any government agency. Mention of companies, technologies, or products is not an endorsement or recommendation. The content is for informational purposes only and should not be considered investment advice.

2  These insights are based on data organized on Pryzm, a defense market intelligence platform and CRM.

3  All references to US capabilities are based exclusively on open-source data from publicly available government reports, think tank analyses, and defense media. While capabilities are often understated rather than overstated in public discourse, this article does not draw on any classified information—regardless of any prior or current access we may or may not have.