Castelion is a modern defense manufacturing company focused on rapidly developing, testing, and mass-producing next-generation military systems, with a core emphasis on hypersonic test and strike capabilities. Founded in 2022 and headquartered in El Segundo, California, Castelion’s mission is to help the United States and its allies maintain a global technical edge and deter future wars by delivering affordable, scalable, and rapidly deployable long-range strike weapons. The company leverages hardware-rich development, vertical integration, and high-cadence iterative testing to reduce the cost and timeline required to bring advanced military systems to operational readiness.
Leadership
Founders:
Bryon Hargis, Co-Founder & CEO: A 20-year aerospace and defense veteran, Hargis previously led sales and business development for SpaceX’s National Security satellite programs, building a multi-billion-dollar pipeline. He holds an M.S. in Applied Physics from Johns Hopkins University and a B.S. in Mechanical Engineering from Georgia Tech.
Sean Pitt, Co-Founder & COO: Formerly led SpaceX’s launch and human spaceflight sales in Europe, securing over $1.25B in export deals with satellite operators and allied defense agencies.
Andrew Kreitz, Co-Founder & CFO: Led SpaceX’s launch forecasting and government cost proposals, and was previously a Vice President at Goldman Sachs focused on aerospace and defense M&A.
Key Team Members:
Jacob Sweers: Experienced in weapon system and spacecraft engineering, with prior roles integrating sensing and weapon systems for the 160th Airborne and leading Starshield development at SpaceX.
Core Technologies
Hypersonic Test Systems: High-cadence testing platforms for rapid evaluation of hypersonic materials and electronic systems.
Strike Systems: Development and manufacturing of long-range hypersonic strike weapons designed for compatibility with existing military platforms.
Vehicle Sub-Systems: Production of solid rocket motors, advanced missile avionics, and seekers.
Vertical Integration: In-house design, testing, and manufacturing to enable rapid iteration and scalable production.
Incremental Design Improvements: Short, iterative design cycles and hardware-rich development to accelerate deployment of new capabilities.
Key Capabilities
Rapid Development: Fast prototyping and deployment of advanced military systems through high-cadence, low-cost testing.
Mass Production: Systems engineered from the outset for affordable, scalable manufacturing.
Compatibility: Strike systems designed to integrate with existing military infrastructure.
End-to-End Manufacturing: From subsystem development (motors, avionics, seekers) to full weapon system integration and testing.
Investors
Total Funding: Over $114 million raised to date.
Initial Funding: $14.2 million in seed funding co-led by Andreessen Horowitz and Lavrock Ventures, announced in 2023.
Series A (2025): $100 million in debt and equity financing led by Lightspeed Venture Partners, with participation from a16z, Lavrock Ventures, Cantos, First In, BlueYard Capital, and Interlagos. Includes $30 million in venture debt from Silicon Valley Bank.
Valuation: Not publicly disclosed.
Company Type: Private.
Notable Clients
U.S. Department of Defense: Castelion’s primary customer base includes U.S. defense agencies seeking advanced hypersonic strike and test capabilities.
U.S. Allies: The company’s systems are designed for use by allied defense agencies, supporting broader deterrence and security objectives.
