Castelion Secures $350M Series B to Expand Hypersonic Missile Development

Castelion, a startup focused on hypersonic weapons, has raised $350 million in a Series B round led by Lightspeed Venture Partners and Altimeter Capital. This follows the company’s $100 million Series A round from earlier in the year. Founded by former SpaceX executives, Castelion aims to transform the production of hypersonic missile systems, which are critical to national security. The company’s approach mirrors that of SpaceX—quick development cycles, frequent testing, and vertical integration—to drive down production costs. The funding comes as the U.S. faces growing competition from China in hypersonic missile technology. In March, Castelion successfully tested its hypersonic vehicle in the Mojave Desert. Additionally, the U.S. Army’s fiscal year 2026 budget request includes $25 million for the development of a new affordable hypersonic missile, Blackbeard Ground Launch (GL), with Castelion potentially playing a pivotal role in its development. If the Army’s field testing proves successful, Castelion could secure larger contracts, making this a highly lucrative opportunity in a competitive market dominated by defense giants like Lockheed Martin and Raytheon.