TL;DR
- Castelion raising $350M Series B led by Lightspeed and Altimeter
- Founded by ex-SpaceX executives, targeting U.S. hypersonic missile market
- Round follows $100M Series A in January 2025
- DoD support includes grants from AFRL and NAVAIR
- Blackbeard GL project under Army FY26 budget, prototype due in 2026
Emerging Defense Tech Startup Secures Massive Investment
Hypersonic missile startup Castelion is reportedly raising $350 million in Series B funding, with Lightspeed Venture Partners and Altimeter Capital leading the round, according to sources and documents reviewed by TechCrunch.
The round, which already has a signed term sheet, will value Castelion in the multi-billion dollar range and is expected to close in the coming weeks. This follows its $100 million Series A in January 2025, which comprised $70 million in equity and $30 million in debt.
Castelion, founded by former SpaceX executives, declined to comment on the funding round.
Castelion’s Defense Trajectory
| Milestone | Details | Source |
| Series B Funding | $350M led by Lightspeed & Altimeter | TechCrunch |
| Series A Funding | $100M (Jan 2025) | TechCrunch |
| Army FY26 Budget Allocation | $25M for Project HX3: Blackbeard GL | U.S. Army Budget Docs |
| Initial Vehicle Test | March 2025 in Mojave Desert | TechCrunch |
| Prototype Delivery Target | Early 2026 | Army Budget FY26 |
Hypersonics: The New Battleground
Hypersonic weapons, capable of speeds exceeding Mach 5, are becoming a focal point of military technology races. While traditional defense primes like Lockheed Martin, Raytheon, and Northrop Grumman dominate this space, the U.S. military has grown concerned about China’s rapid advances in hypersonic deployment.
Castelion aims to disrupt the field using SpaceX-style tactics: vertical integration, rapid iteration, and cost-efficient scaling. Its first hypersonic test vehicle flew in the Mojave Desert earlier this year.
Project Blackbeard: Affordable Hypersonic at Scale
A major validation for Castelion came via the U.S. Army FY2026 budget, which earmarks $25 million for Project HX3. Under this initiative, Castelion will develop and test an “affordable, mass-produced hypersonic weapon” called Blackbeard Ground Launch (GL).
The Blackbeard GL is designed to deliver roughly 80% of the capabilities of current high-end hypersonic weapons — but at a significantly reduced cost. The Army appears willing to trade slight reductions in speed and range for budget-conscious scalability.
Deployment Timeline and Strategic Impact
The first phase of the Army contract includes delivery of a prototype proof-of-concept in early 2026. If that proves successful, a second phase would follow in 2027 with the deployment of 10 additional test missiles using the High Mobility Artillery Rocket System (HIMARS).
Notably, Blackbeard is being designed for compatibility with autonomous launch platforms, offering future operational flexibility.
If field testing is successful, full-scale delivery contracts could begin in 2028, catapulting Castelion into a top-tier position in the defense sector.
Government Backing: Grants and Integration
Castelion has already earned recognition from several Department of Defense agencies, including:
- Air Force Research Laboratory (AFRL)
- Naval Air Systems Command (NAVAIR)
This early traction underscores confidence in Castelion’s engineering approach and production model, even as a relatively new entrant.
The Stakes: Disrupting Defense Giants
While Raytheon, Lockheed Martin, and Northrop Grumman have the legacy relationships and infrastructure, Castelion’s agile development model and rising federal support are making it a viable challenger in the hypersonic arms race.
Should Castelion secure mass production rights for Blackbeard or similar systems, it may spark a new era of competition in U.S. defense procurement — one that favors speed and cost-effectiveness over legacy scale.
