Castelion
Castelion is a Propulsion & Manufacturing company founded in 2022 and based in El Segundo, United States. It has raised $1.4B in total funding, most recently a Series C in 2026 at a $13B valuation.
Castelion was founded in 2022 and is headquartered in El Segundo, United States. The company designs and manufactures the Blackbeard hypersonic strike weapon, a long-range system with vertically integrated solid rocket motors, control actuation systems, guidance computers, and thermal protection built in-house. Revenue streams derive from defense contracts: the US Navy awarded Castelion $49.9 million for F/A-18 integration with Early Operational Capability targeted in 2027, and the US Army included Blackbeard in its FY2026 budget. As of August 2026, Castelion had raised $1.434 billion in total funding, including a Series C round of $1 billion announced at an $13 billion valuation.
Castelion operates in hypersonic weapon development and manufacturing at a time when the US military is advancing these systems toward operational deployment. The company's Series C funding at a $13 billion valuation reflects investor confidence in scaling production of a weapon system across multiple service branches. Completion of over 20 development flight tests in 2025 and active integration with the F/A-18 platform signal technical maturation and near-term transition to operational use.
castelion.com ↗·Propulsion & Manufacturing·
United States·private 
