Castelion Closes $350 Million Series B to Mass Produce U.S. Hypersonic Weapons

Funding Accelerates U.S. Manufacturing Expansion and Scaled Production of Affordable Hypersonic Weapons to Meet Pentagon's Top Priority

TORRANCE, Calif., Dec. 5, 2025 /PRNewswire/ -- Castelion, a cutting-edge defense technology company working to restore America's conventional deterrence capability, announced today it raised $350 million in Series B financing, positioning the company to directly advance a top Pentagon modernization priority: hypersonic munitions production at scale.

The capital raise supports critical technical and manufacturing milestones: integrating Castelion's first hypersonic weapon, Blackbeard, with U.S. Army and U.S. Navy operational platforms; building its production and final-assembly facility, Project Ranger; and multi-service platform testing in 2026.

The round was led by Altimeter Capital and Lightspeed Venture Partners, with participation from Lavrock Ventures, Andreessen Horowitz, General Catalyst, First In, Space VC, Cantos, BlueYard, Avenir, Champion Hill, and Interlagos.

"Blackbeard helps close America's hypersonic capability gap against China and Russia," said Bryon Hargis, CEO and Co-Founder of Castelion. "This funding lets us build fast, test often, and produce at volumes that matter in the real world."

CAPITAL DEPLOYMENT: SPEED TO PRODUCTION

The company's latest investment round enables Castelion to expand manufacturing and workforce development across the United States:

Project Ranger (Sandoval County, New Mexico): Tooling, commissioning and production ramp at the 1,000-acre solid rocket motor manufacturing campus announced in November. The facility will be capable of producing thousands of Blackbeard missiles per year and support hundreds of industrial high-skilled jobs in the region.

Test Cadence and Platform Integration: Continuing high-tempo test cadence in 2026 with increasingly complex capability demonstrations and integration with operational launch platforms.

Follow-on System Development: Parallel maturation of a second hypersonic product line, leveraging shared low-cost subsystem infrastructure.

INVESTOR CONFIDENCE IN DEFENSE INNOVATION

"Castelion was founded by a special team of SpaceX alumni who, in just 2.5 years, took a clean-sheet hypersonic from concept to 25+ flight tests and major integration contracts," said Erik Kriessmann, Partner at Altimeter Capital. "We're leading this round because of what they've achieved in record time and so they can rapidly scale production of one of the U.S. Department of War's most critical capabilities: affordable, mass-produced hypersonics, from hundreds to thousands of missiles per year."

"Castelion isn't just building missiles; they're rebuilding America's industrial depth," said Connor Love, Partner at Lightspeed Venture Partners. "This team has proven they can move from blank sheet design to hardware under test faster than anyone thought possible."

"Lavrock invests in critical technologies that strengthen America's national security, and Castelion is doing exactly that," said Alex Poulin, Partner at Lavrock Ventures. "Hypersonics only matter if you can build them at scale. Castelion's team understands that, and they're engineering a production-ready capability designed for real-world manufacturing and deployment. We're proud to be early backers of a team focused on delivering capacity, not just concepts."

"Hypersonic weapons capacity will shape great power competition for generations," said Katherine Boyle, General Partner at Andreessen Horowitz. "China recognized this a decade ago and deployed at scale. Castelion leads America's arsenal renewal with the speed, cost advantage, and volume at scaled production that our nation demands."

"Castelion is transforming the economics of our defense industrial base," said Paul Kwan, Managing Director, General Catalyst. "Modern deterrence demands hypersonic capability at a pace, scale and cost that the U.S. has never seen."

BREAKING THE COST-SPEED PARADIGM

In 2025, Castelion conducted more than 20 development flight tests, validating weapon-critical subsystems including internally manufactured solid rocket motors, control actuation systems, flight computers, seekers, thermal protection materials, and mission software. Each campaign focuses on low-cost, mass-producible architectures which replace designs historically built in low volumes, at extreme cost, or only on multi-year timelines.

Castelion's approach compresses design-to-launch cycles from years to months and establishes the industrial base required for high-rate missile production, not boutique inventory.

ABOUT CASTELION

Castelion builds American hypersonic deterrence through rapid, affordable, and scalable production of advanced strike weapons. Blackbeard is the first U.S. hypersonic system engineered from inception for industrial-rate output, commercial unit cost, and continuous flight test iteration. The company is headquartered in Torrance, California, with manufacturing operations in New Mexico, Texas, and California. For more information on Castelion, please visit www.castelion.com.

ABOUT ALTIMETER CAPITAL

Altimeter is a technology-focused investment firm built by a founder for founders. Altimeter's mission is to help visionary entrepreneurs build iconic companies, disrupt markets and improve lives through all stages of growth. Altimeter manages a variety of funds that invest in the public and private markets and seeks to serve as an expert long-term partner to companies as they enter the public markets.

ABOUT LIGHTSPEED VENTURE PARTNERS

Lightspeed is a global, multi-stage, venture capital firm managing over $40B in assets. Since its founding in 2000, Lightspeed has been the first investor and an early backer of some of the most innovative companies in the world including Abridge, Anthropic, Castelion, Glean, Mistral, Navan, Netskope, Rubrik, Snap, Wiz, and more. Learn more at lsvp.com.

SOURCE Castelion