Senior Structures & Composites Engineer; Rocket Motor Cases

Senior Structures & Composites Engineer (Rocket Motor Cases)

Castelion is moving incredibly fast to develop and deliver advanced defense systems at a time when execution matters more than ever. We believe focus and technical excellence are decisive advantages - and we are building a team that can deliver real capability, not just concepts.

This is a rare opportunity to join at an early stage, where your work will directly shape critical systems, influence major technical decisions, and have immediate, real-world impact.

We are seeking a Senior Structures & Composites Engineer to design and deliver high-performance rocket motor cases for Castelion's long-range hypersonic strike vehicles. This role is critical to enabling lightweight, high-strength propulsion structures capable of withstanding extreme pressure and thermal environments. You will work hands-on with multidisciplinary engineering teams to design, analyze, build, and validate composite and metallic motor case structures in a fast-paced, hardware-driven environment.

• Design and develop rocket motor case structures, including composite over wrapped pressure vessels (COPVs) and filament-wound composite cases
• Lead the architecture and detailed design of motor cases, including load paths, interfaces, domes, bosses, and attachment features
• Perform structural analysis of pressure vessels under internal pressure, thermal loads, and dynamic environments to ensure performance and reliability
• Develop and analyze composite layups, fiber orientations, and manufacturing approaches to optimize strength, stiffness, and mass
• Work closely with propulsion, materials, manufacturing, and test teams to ensure seamless integration of motor cases with propulsion systems
• Support material selection, processing, and characterization for composite and high-temperature materials
• Conduct failure analysis and root cause investigations, driving design improvements and risk reduction
• Define and execute qualification and environmental test plans, including pressure testing, proof/burst testing, and vibration testing
• Support prototyping, fabrication, and hardware bring-up, including troubleshooting manufacturing and structural performance issues
• Optimize designs for mass efficiency, manufacturability, and operational reliability
• Mentor junior engineers and contribute to best practices in composite and pressure vessel design
• Partner closely with program leadership to make technical trades aligned with mission success

• Bachelor's, Master's, or PhD in Aerospace Engineering, Mechanical Engineering, or related field
• 5+ years of experience in structural and composite design for aerospace or high-performance pressure vessel applications
• Strong background in composite materials, including filament winding, laminate theory, and failure criteria (e.g., Tsai-Wu, Hashin)
• Experience designing pressure vessels, COPVs, or rocket motor cases for high-pressure applications
• Proficiency in structural analysis tools (e.g., ANSYS, Abaqus, NASTRAN, or equivalent)
• Familiarity with manufacturing processes for composites, including winding, curing, and inspection methods (e.g., NDI/NDT)
• Experience with proof/burst testing and structural validation of pressure vessels
• Experience with hardware build, test, and troubleshooting in a lab or production environment
• Strong problem-solving mindset, thriving in a fast-paced, hardware-rich, high test cadence environment

While this position does not currently require a U.S government-issued security clearance, it may in the near future. Therefore, the ability to obtain and maintain a U.S. government–issued security clearance is required. U.S. citizenship is required, as only U.S. citizens are eligible for a security clearance.

Employment with Castelion is governed on the basis of competence and qualifications and will not be influenced in any manner by race, color, religion, gender, national origin/ethnicity, veteran status, disability status, age, sexual orientation, gender identity, marital status, mental or physical disability or any other legally protected status.