Why Castelion, Why Now 

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.  

Senior Structures & Composites Engineer (Rocket Motor Cases)

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.

Responsibilities

• Design and develop rocket motor case structures, including composite overwrapped 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

Basic Qualifications

• 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

 

Castelion offers a generous benefits package. Please refer to the bottom of our Careers page for more details.  

Other Duties 

Please note this job description is not designed to cover or contain a comprehensive listing of activities, duties or responsibilities that are required of the employee for this job. Duties, responsibilities and activities may change at any time with or without notice. 

Additional Eligibility Requirements 

This position may require access to classified information or restricted U.S. Government sites, systems, or information, as determined by the Company and/or applicable U.S. Government requirements. If the position is so designated, your employment in the role may be contingent upon your ability to obtain and maintain the required U.S. Government security clearance or other government authorization, and to satisfy any citizenship or other eligibility requirements imposed by applicable law, regulation, executive order, or government contract requirements. You will be notified if and when such requirements apply. 

Affirmative Action/EEO Statement 

Castelion is an Equal Opportunity Employer. We are committed to providing equal employment opportunities to all applicants and employees without regard to race, color, religion, sex, sexual orientation, gender identity, national origin, age, disability, genetic information, protected veteran status, or any other characteristic protected by applicable federal, state, or local law. 

Castelion is committed to providing reasonable accommodations to qualified individuals with disabilities throughout the application and hiring process. If you require a reasonable accommodation to complete an application, participate in the interview process, or otherwise participate in the hiring process, please contact hr@castelion.com. Requests for accommodation will be considered on an individual basis and handled in accordance with applicable law. 

Castelion is committed to fostering a workplace where employment decisions are based on qualifications, business needs, and the ability to perform the essential functions of the role, with or without reasonable accommodation. 

EAR/ITAR Requirements 

This position requires access to export-controlled information, and as such, employment (or hiring of a contractor) is contingent upon the candidate’s ability to access all applicable export-controlled information without additional export licensing being required by the Bureau of Industry and Security and/or the Directorate of Defense Trade Controls.