Castelion

Castelion is a defense technology company developing hypersonic missiles for the U.S. military, built around the goal of mass-producing these weapons at lower cost rather than treating each one as a bespoke, expensive research project. Founded in November 2022 by former SpaceX engineers Bryon Hargis (CEO), Sean Pitt (COO) and Andrew Kreitz (CFO), Castelion is headquartered in El Segundo, California, with additional operations in Allen and Midland, Texas.

Castelion’s approach to defense manufacturing

Castelion has positioned itself around applying commercial aerospace manufacturing techniques, the kind pioneered at companies like SpaceX, to military hardware, aiming to produce hypersonic missiles faster and at substantially lower unit cost than the U.S. defense industry has traditionally achieved. This approach reflects a broader trend among a newer wave of venture-backed defense technology startups seeking to compete with longtime, established defense contractors by emphasizing rapid iteration and manufacturing scale over slower, more traditional government-contracting development cycles.

Castelion’s funding and valuation

Castelion closed a $350 million Series B funding round, reported in July 2025 and led by Lightspeed and Altimeter with participation from Pritzker Group, bringing its total capital raised to roughly $450 million at the time. In August 2026, reports described the company securing a $1 billion funding round that valued Castelion at approximately $13 billion, reflecting a rapid escalation in investor interest in defense technology startups amid heightened government spending on hypersonic weapons programs.

Government contracts and testing

Castelion has received grants from the Air Force Research Laboratory and the Naval Air Systems Command to support development of its missile systems, and conducted a hypersonic vehicle test in the Mojave Desert in March 2024. In June 2025, the U.S. Army’s fiscal year 2026 budget request sought $25 million under a program called Project HX3 for Castelion’s Blackbeard GL missile, reflecting growing military interest in the company’s production-focused approach to hypersonic weapons.

Why hypersonic weapons startups have attracted investment

Hypersonic weapons, which travel at more than five times the speed of sound, have become a priority area for U.S. defense spending as the military seeks to keep pace with hypersonic weapons programs in other countries. Castelion’s pitch to investors and the Pentagon centers on manufacturing speed and cost: rather than building a small number of expensive, highly customized missiles, the company aims to produce them at a scale closer to commercial aerospace manufacturing, a value proposition that has attracted some of the same venture investors backing other recent defense technology startups.

Castelion in context among defense tech startups

Castelion is part of a broader wave of venture-backed defense technology companies, alongside firms like Anduril and SpaceX itself, that have attracted significant investment by applying commercial technology-company methods, rapid iteration, software-driven design and private capital, to defense hardware traditionally built by a small number of large, established contractors. This shift has drawn both investor enthusiasm and scrutiny over how quickly newer entrants can actually deliver working weapons systems at the scale and reliability the military requires.

FAQs

When was Castelion founded? Castelion was founded in November 2022 by former SpaceX engineers Bryon Hargis, Sean Pitt and Andrew Kreitz, and is headquartered in El Segundo, California.

How much funding has Castelion raised? Castelion raised a $350 million Series B in July 2025, bringing total funding to about $450 million at the time, and later reports in August 2026 described a $1 billion round valuing the company at approximately $13 billion.

What makes Castelion’s approach different from traditional defense contractors? Castelion applies commercial aerospace manufacturing techniques to aim for mass production of hypersonic missiles at lower cost, rather than developing each missile as a small-batch, highly customized project the way traditional defense contractors often have.

What is Project HX3? Project HX3 is a U.S. Army program that, per its fiscal year 2026 budget request, sought $25 million to support Castelion’s Blackbeard GL missile.

Has Castelion delivered weapons to the U.S. military yet? As of the sources available, Castelion has conducted testing, including a hypersonic vehicle test in the Mojave Desert in March 2024, and received development funding and interest from military programs, but detailed information on full operational deployment was not available in the sources reviewed.

Editorially reviewed by Specialty Digest Editorial TeamLast reviewed November 9, 2026Researched and drafted with AI assistanceReport an issue