Castelion Raises $1 Billion to Scale Low-Cost Hypersonic Weapons
Castelion’s central challenge is not building a hypersonic weapon but manufacturing thousands of them at low cost, according to co-founder and CFO Andrew Kreitz. The defense startup, valued at $13 billion after raising $1 billion, plans to begin producing its Blackbeard strike system next year while advancing a larger long-range weapon and interceptors. Kreitz says his experience in SpaceX’s finance organization shaped the company’s view that defense-system costs reflect supply-chain choices and customer incentives, not an unavoidable constraint.
The central problem is manufacturing thousands of weapons at low cost
Andrew Kreitz describes Castelion’s technical mission in terms that put manufacturing ahead of the individual weapon. Its first product, Blackbeard, is a hypersonic strike system well into development. The immediate purpose of the new financing, he says, is to move at “maximum speed” toward production next year—and, after the first article is delivered, raise the rate at which the company can produce it.
For Kreitz, that production ramp is the actual test. “Nothing matters until we are manufacturing at scale,” he says. The hard engineering problem is not producing a single capable unit, but producing “thousands and thousands and thousands” at low cost. Castelion has backward-planned its work from that objective since founding: get Blackbeard into production quickly, then establish the capacity to make it in quantity.
The real engineering challenge here, the real difficulty is not how do you make one unit, it’s how do you make thousands and thousands and thousands at low cost.
The company is pursuing three related product areas. Blackbeard is the near-term system. A second weapon, under development since 2023, is larger and longer-range, intended for different platforms and a different class of weapon. Kreitz calls that program the “north star” product Castelion was formed to build, and says the new round will accelerate it.
The third area is interception: defensive systems designed to counter incoming threats. Kreitz points to events in the Middle East as a reminder of the need for interceptors that can be produced at scale and at low cost.
Castelion is described on screen as a builder of low-cost hypersonic strike missiles, with a $13 billion valuation and more than $500 million in U.S. military contracts.
The new capital has to fund a production ramp, not just development
Castelion’s Series C combines $800 million in equity with $250 million committed to a revolving credit facility. Ed Ludlow notes that the financing is ahead of the company’s current contract base; Kreitz’s account of its use is correspondingly broader than finishing a single product.
The immediate operational objective is Blackbeard production next year. But Kreitz distinguishes reaching that first delivery from the work that follows it: sustaining and increasing output. The company’s stated challenge is to close out development while building the capacity, supply chain, and production rate required for quantity manufacturing.
The funding also supports the larger, longer-range strike system that Castelion has worked on since 2023, along with its interceptor effort. In Kreitz’s framing, the round is intended to let the company push all three efforts forward while keeping Blackbeard’s production ramp as the near-term priority.
The investor group includes Andreessen Horowitz, J.P. Morgan, Carlyle, Lightspeed, General Catalyst, and Altimeter. Kreitz says Castelion ran a competitive process and selected partners deliberately. He draws a distinction between early-stage hardware investors such as Andreessen Horowitz—whose early risk tolerance and hardware network he values—and firms such as J.P. Morgan and Carlyle, which he says bring experience and networks across capital markets, government, and aerospace and defense.
That mix matters, Kreitz argues, because the company is moving from development toward a business that must demonstrate cash-flow potential as well as technical execution. He presents the participation of established financial and defense investors as a signal of that maturity to public markets.
The SpaceX lesson was that defense costs are shaped by incentives
Kreitz traces a core part of Castelion’s founding thesis to his experience in SpaceX’s finance organization, where he worked on costing. He says SpaceX exposed him to different ways of doing engineering, verticalizing the supply chain, and focusing on removing cost from complex systems. The lesson was not that aerospace systems are easy to make, but that their prevailing cost structure is not necessarily inherent.
Andrew Kreitz says that experience “opens up your mind” to the possibility that such systems do not have to be as expensive as they currently are. Castelion’s approach therefore centers not only on weapon capability, but on supply-chain structure and cost.
If the requirement is mass scale, low cost, still high capability, but focus on that scale and that quantity aspect, that’s what we can drive towards.
Kreitz does not put the pressure for lower costs solely on Castelion or solely on the U.S. government. He describes the result as a function of incentives. If the priority is “exquisite capability” and the expectation is that weapons will not be needed in large quantities, industry will build accordingly. A requirement for mass scale, low cost, and high capability should drive a different response.
The market case, in his view, extends beyond the United States. Kreitz points to allies and partners in Europe, where the war in Ukraine has focused attention on defense production, and to the Western Pacific. In the post-Cold War era, he says, many allies and partners reduced their focus on defense production and scale.
Castelion’s intended offering to the United States and allied customers is that scale: strike weapons and defensive systems that can be produced in volume.