Senior Mechanical Design Engineer (ACS Systems)

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 were building a world-class team to turn bold ideas into real capability.

This is a rare opportunity to join at an early stage where youll 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 Mechanical Design Engineer (ACS Systems)

We are seeking a Senior Mechanical Design Engineer to design and deliver attitude control system (ACS) hardware for Castelions long-range hypersonic strike vehicles. This role is critical to enabling reliable propellant storage flow control and thrust generation for precise vehicle control. You will work hands-on with multidisciplinary engineering teams to design analyze build and validate ACS tanks valves thrusters and integrated assemblies in a fast-paced hardware-driven environment.

Responsibilities

• Design and develop ACS hardware including propellant tanks valves thrusters and associated fluid system assemblies
• Lead the architecture and detailed design of pressure vessels fluid lines mounts and integrated ACS packaging within the vehicle
• Perform structural thermal and fluid analyses to ensure performance and reliability under extreme pressure temperature and dynamic environments
• Work closely with propulsion GNC avionics and structures teams to ensure seamless integration of ACS systems with vehicle architecture
• Conduct tolerance analysis sealing strategy development and leak-tightness assessments for high-pressure systems
• Support prototyping assembly and hardware bring-up including troubleshooting and root cause analysis of system performance issues
• Define and execute qualification and environmental test plans including pressure vibration thermal and shock testing
• Optimize designs for mass reliability manufacturability and ease of integration
• Mentor junior engineers and contribute to best practices in mechanical and fluid system design
• Partner closely with program leadership to make technical trades aligned with mission success

Basic Qualifications

• Bachelors Masters or PhD in Mechanical Engineering or related field
• 5 years of experience in mechanical design for aerospace or high-performance fluid/propulsion systems
• Strong background in pressure vessel design fluid systems and high-pressure component integration
• Experience designing tanks valves thrusters or similar propulsion or ACS hardware
• Familiarity with sealing methods leak detection and cleanliness requirements for high-reliability fluid systems
• Proficiency in CAD and analysis tools (e.g. NX SolidWorks ANSYS or equivalent)
• Experience with structural analysis thermal analysis and tolerance stack-up analysis
• Familiarity with high-temperature materials and operation in extreme environments
• Experience with hardware build test and troubleshooting in a lab or flight hardware environment
• Strong problem-solving mindset thriving in a fast-paced hardware-rich high flight 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 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 candidates 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.

Required Experience:

Senior IC