Hardware Designed for Production at Scale

Castelion delivers the capabilities America needs to preserve peace through credible, non-nuclear deterrence. We build at the scale national security demands – optimizing every system for cost, manufacturability, and rapid deployment.

Hardware Rich.

Rapid Test and Iteration.

Designed for Scaled Manufacturing.

Affordable Hypersonic Weapons, Built Fast

At Castelion, speed and cost aren’t tradeoffs – they’re requirements. We vertically integrate core technologies to move faster, reduce risk, and control cost at scale. Every system is designed for manufacturability from day one, enabling rapid iteration and high-volume production. In today’s threat environment, speed matters. Affordability matters. We’re building with both.

Protecting Democracy

Our mission is rooted in the belief that freedom must be actively protected – through technological strength, strategic clarity, and national resolve. By restoring America’s ability to out-innovate and out-produce its rivals, we help ensure that the free world remains secure for generations to come.

Hardware Rich

Rapid Testing

Iterative Design

America Needs You!

Ready to get your hands on real hardware, own critical projects, and make your work count? Explore our open roles and help shape the future of defense.

Featured Positions

Choose your next adventure with Castelion.

Castelion News

Castelion Secures Multiple Awards to Integrate Blackbeard Hypersonic Strike Weapon on U.S. Army and U.S. Navy Platforms
October 24, 2025

Castelion Secures Multiple Awards to Integrate Blackbeard Hypersonic Strike Weapon on U.S. Army and U.S. Navy Platforms

Castelion long-range strike weapons, announced today that it has been awarded integration contracts for its Blackbeard weapon system with operational U.S. Army and U.S. Navy platforms.

Under these agreements, Castelion will work with both services to integrate the hypersonic Blackbeard weapon system onto operational platforms and demonstrate its capabilities in live-fire tests – advancing the Department of War’s effort to evaluate and accelerate new, cost-effective strike capabilities for conventional deterrence.

February 13, 2025
Source: The Economist

Defence tech is blowing up Silicon Valley’s beliefs

In the back of an unmarked office building close to LAX, the main airport of Los Angeles, stands a rack of unarmed hypersonic missiles the size of small drainpipes. On February 6th a camouflaged truck ferried one away to New Mexico for a test launch with the US Air Force. Such activity used to be common in El Segundo, the LA neighbourhood that was once a hub of military spaceflight.

February 13, 2025
Source: WSJ

Startup Castelion Raises $100 Million for Hypersonic Strike Weapons

Silicon Valley’s enthusiasm for superfast weapons has picked up speed, with defense-tech startup Castelion raising $100 million through debt and equity to build hypersonic missile systems.

January 29, 2025

Castelion Announces Series A Funding

Castelion is excited to announce a $100M capital raise. This includes a $70M Series A, led by Lightspeed Venture Partners with participation from a16z, Lavrock Ventures, Cantos, First In, BlueYard Capital, and Interlagos, and $30M in Venture Debt financing provided by Silicon Valley Bank, with final close expected in February. With this funding we will further accelerate test cycles, scale our mass production facilities, and execute a capability demonstration of our first hypersonic weapon. These efforts will move us faster and closer to regaining a decisive advantage and thereby creating credible deterrence.