Castelion is moving incredibly fast to develop and deliver advanced defense systems at a time when execution matters more than ever. We believe focus, ownership, and excellence are decisive advantages - and we're building a world-class team to turn bold ideas into real capability.
This is a rare opportunity to join at an early stage, where you'll have significant ownership, collaborate with exceptional teammates, and make a direct, measurable impact on our mission and the future of the company - regardless of your function.
Summer 2027 Mechanical Engineering Internships
Join us for a dynamic, hands-on experience developing next-generation missile systems. As an intern, you'll contribute directly to the design, testing, and integration of advanced defense technologies all within a fast-paced, collaborative startup environment where your work has immediate impact.