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Editor’s Brief

Last week, we looked at how Vannevar Labs is embedding engineers with combat units to accelerate battlefield software development. By collapsing the gap between operators and technologists, they’re proving that capability doesn’t have to wait for a POR. As Colin Hively puts it in The Attainable Pipe Dream: An Intra-Battle Innovation Cycle: “The challenge is to institutionalize that survival-based incentive to innovate into our procurement processes, so that we don’t have to fight tomorrow’s war with yesterday’s equipment.”

This week, we spotlight Castelion, a hypersonics startup applying SpaceX-style manufacturing to build strike weapons. Their $100M raise and traction across three service branches suggest growing trust—but success hinges on whether they can scale production.

As always, your feedback shapes our coverage—reply directly with insights or questions.

Signal Brief: Castelion - Scaling Hypersonic Deterrence Through Strength

Castelion is taking a fundamentally different approach to defense manufacturing: build advanced hypersonic weapons using commercial aerospace practices to enable speed, affordability, and scale. Their goal is to close a growing gap in U.S. deterrence—fielding long-range precision strike capabilities fast enough, and in large enough numbers, to matter.

Origins & Vision

Founded in November 2022, Castelion emerged from a recognition that America's deterrence posture was being undermined by the defense industrial base's inability to rapidly field weapons at scale. Bryon Hargis (CEO), who previously led SpaceX's national security satellite business development, partnered with Sean Pitt (COO), who spearheaded SpaceX's European launch and human spaceflight sales, and Andrew Kreitz (CFO), a former Goldman Sachs investment banker and SpaceX finance manager for classified programs.

After witnessing how SpaceX revolutionized space access through rapid iteration and vertical integration, the founding team became convinced that similar approaches could transform defense production. Within months of launching, Castelion had secured multiple government contracts and begun component testing. By March 2024—just 16 months after founding—they completed their first flight test of a prototype hypersonic missile in the Mojave Desert, demonstrating remarkable speed from concept to flight test.

This experience shaped Castelion's core philosophy: modern manufacturing techniques and rapid development cycles can dramatically accelerate weapons fielding while reducing costs. By vertically integrating critical subsystems (solid rocket motors, missile avionics, thermal protection materials, and guidance systems), they aim to shrink development timelines from years to months while ensuring capability meets operational requirements.

Key Takeaways

• Commercial Speed in Defense: Castelion’s timeline from concept to flight test—just 16 months—shows how fast vertically integrated teams can move.

• Strategic Cost Imposition: By making hypersonics affordable, Castelion forces adversaries into an unfavorable tradeoff: spending billions to counter weapons that cost millions.

• Cross-Service Adoption: Contracts from three military branches demonstrate technical versatility that could become a template for accelerating capabilities.

• Investment Signal: A $100M Series A is a strong signal that institutional capital is warming to defense manufacturing as a high-growth sector.

Tech Radar: Castelion’s Strike Architecure

Hypersonic Strike Weapon – Affordability Through Modern Manufacturing

Castelion’s flagship platform is a long-range, Mach 5+ missile with maneuverability and precision, designed to be difficult to track and intercept. It’s designed and built to fully integrate with existing Army, Navy, and Air Force launch platforms, though operational integration has not yet been publicly demonstrated.

Key Capabilities

• End-to-End Strike Package – Missile, launcher, and datalink in one system

• Platform-Agnostic Design – Designed for cross-service compatibility

• High-Cadence Testing – Enables rapid iteration and validation through frequent flight tests.

• Conventional-Only Payload – Offers scalable, non-nuclear deterrence for precision stand-off strike.

Integrated Development Model

What sets Castelion apart is its vertically integrated approach—designing and building core systems like propulsion, thermal protection, avionics, and guidance entirely in-house. This model, inspired by SpaceX, enables tight feedback loops, rapid iteration, and fewer delays from external suppliers. Its Midland, Texas facility anchors this strategy, combining test infrastructure and production tooling to support the transition from flight testing to scalable manufacturing.

Market & Career Signals

Funding and Growth

• Total Funding: $114.2 million across Seed and Series A rounds

• Latest Round: $100 million in February 2025, comprising $70 million in equity and $30 million in venture debt

• Notable Investors: Lightspeed Venture Partners, Andreesen Horowitz (a16z), Lavrock Ventures, Cantos, First In, BlueYard Capital, and Interlagos

• Valuation: Currently undisclosed

The financing structure—combining both equity and venture debt—suggests confidence in Castelion's ability to secure significant future government contracts. The debt component provides non-dilutive capital that extends runway while indicating potential revenue from pending contracts.

While Castelion is clearly focused on defense-first applications, its core technologies could support future dual-use opportunities in responsive space access or in-orbit delivery, aligning with broader trends in national security tech.

Contracts & Government Traction

Castelion has secured multiple contracts from across the Department of Defense, including:

• Air Force SBIR Phase II – ~$1.8M for "Low-Cost Highly Manufacturable Long-Range Strike Weapon" research

• Air Force SBIR Phase III – $15.75M follow-on for scalable strike weapon production

• Office of Naval Research – $3.0M R&D contract for hypersonic technologies

• DoD Hyper-AMPD Prize Award – Winner of the Joint Hypersonics Transition Office's Hyper-AMPD challenge

While these early contracts are primarily R&D, Castelion’s ability to secure awards from all three service branches signals strong alignment with joint mission needs. By leveraging SBIR Phase III authority to secure sole-source follow-on funding, the company is navigating defense procurement with notable agility—potentially creating a direct path to scaled production.

A broader look at Department of Defense hypersonics funding shows a surge over the past five years, with total investment climbing from under $2B in FY2019 to nearly $10B in FY2024. While funding is projected to decline to approximately $8.8B in FY2025, the Future Years Defense Program (FYDP) still allocates over $33B toward hypersonic weapons development and procurement. This reflects a sustained commitment to advancing long-range strike capabilities across the services. Castelion’s early traction positions it well within this broader funding environment, especially as the Pentagon shifts from R&D to deployment.¹

Impact for Defense Professionals

Castelion’s model reflects broader trends shaping the future of defense development. Key takeaways:

• Technical Agility: Bridging traditional aerospace experience with fast-cycle iteration is becoming a critical advantage.

• Acquisition Fluency: Understanding SBIR, OTAs, and alternative contracting paths is increasingly essential.

• Manufacturing at Scale: As DoD priorities shift toward volume, professionals with experience in production engineering, quality, and throughput will be in high demand.

• Shifting Supply Chains: Vertical integration is challenging the traditional prime-subcontractor model—suppliers must offer both cost and speed advantages to remain competitive.

The greatest leverage remains with those who can bridge the “valley of death” between prototype and production. In today’s defense industrial base, that transition is where the real value is created.

Looking Ahead

China's hypersonic arsenal—most notably the DF-17 (∼2,500 km range) and the DF-27 (estimated 5,000–8,000 km range)—increasingly threatens U.S. military assets across the Western Pacific. These systems give the PLA Rocket Force the ability to hold targets like Carrier Strike Groups and bases in Guam at risk, potentially extending reach as far as Hawaii or even the western continental U.S. The threat is compounded by China’s deployment strategy: hundreds of road-mobile launchers that are difficult to track and expensive to neutralize, creating an asymmetric dilemma that strains traditional U.S. deterrence models.²

This growing threat has reignited debate over missile defense. In January 2025, President Trump signed an executive order calling for the development of a nationwide missile defense system —an initiative dubbed the "Iron Dome for America." The proposal envisions scaling proven concepts from systems like Israel’s Iron Dome to continental scope, a technically and financially daunting challenge. Lockheed Martin, named as a central partner, faces the dual burden of sustaining legacy programs like the F-35 while tackling the complexity of next-generation interceptors.

For Castelion to transform deterrence, it must deliver on high-cadence testing and production—fielding thousands of missiles, not dozens—to create the magazine depth that reshapes strategic equations. Current U.S. programs like the Army’s Long-Range Hypersonic Weapons and the Navy’s Conventional Prompt Strike Programs continue to face development hurdles and delayed deployment timelines. Castelion’s investment in its Midland, Texas facility signals real intent to meet that scale, but the path from prototype to mass production is where most programs stall.

The company’s philosophy challenges the traditional focus on exquisite performance. It argues that the U.S. doesn’t need superiority in every metric—just systems that are reliable, rapidly deployable, and produced in sufficient quantity to impose cost and risk on adversaries. If Castelion can sustain velocity through the manufacturing phase, its approach could prove decisive as the hypersonic arms race enters its next phase

Challenges:

• Manufacturing Scale-Up – Moving from prototype to sustained production while maintaining quality, throughput, and cost control.

• Technology Maturation – Demonstrating full-system performance under operational conditions, beyond individual subsystem success.

• Incumbent Competition – Competing with legacy primes that dominate acquisition cycles and have entrenched relationships across the DoD.

• Contract Transition – Converting R&D wins into production contracts within a traditionally risk-averse procurement environment.

Bottom Line:

Castelion represents a new class of defense contractor—combining the speed and flexibility of commercial aerospace with systems built for real-world military impact. If they can scale production and meet performance targets, they could help shift U.S. deterrence strategy from a handful of high-cost platforms to a distributed, high-volume strike force.

The next 18–24 months will be critical. Once Castelion completes its Midland, Texas facility, a potential partnership on the AIM-174B—paired with full-scale production and forward deployment of strike weapons to Guam and other Pacific bases—would send a clear signal: the U.S. can respond to China’s mobile hypersonic arsenal not with exquisite one-offs, but with volume, speed, and credible reach.

But firepower alone won’t ensure stability. As during the Cold War, diplomacy and signaling will matter as much as missile counts. Castelion’s trajectory could not only reshape the defense industrial base—but also influence how deterrence itself is defined in a new era of strategic competition.

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

2  All references to Chinese missile 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.