Senior Propulsion Engineer (Rocket Motor Nozzles)

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 Propulsion Engineer (Rocket Motor Nozzles)

We are seeking a Senior Propulsion Engineer to design and deliver rocket motor nozzles for Castelion's long-range hypersonic strike vehicles. This role is critical to ensuring reliable motor performance, structural integrity, and thermal protection through the design of metallics, composites, insulation, etc. You will work hands-on with multidisciplinary engineering teams to design, analyze, build, and validate soft goods systems in a fast-paced, hardware-driven environment.

Responsibilities

• Design and develop rocket motor nozzle components, including interfacing hardware, high-temperature environment-performing ablatives and insulators, adhesives, and metallic housings.
• Lead the architecture and detailed design of propulsion hardware to meet performance, structural, and thermal requirements
• Perform thermal and structural analyses to ensure performance and durability under high-temperature, high-pressure environments
• Develop and optimize material selections and formulations in collaboration with materials and manufacturing teams
• Work closely with propulsion, structures, and manufacturing teams to ensure seamless integration of soft goods with overall motor design
• Support material processing, fabrication, and quality control of soft goods components
• Plan and execute test campaigns, including subscale and full-scale motor testing, and analyze results to drive design improvements
• Conduct failure analysis and root cause investigations related to insulation performance, erosion, cracking, or debonding
• Mentor junior engineers and contribute to best practices in soft goods design and processing
• 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 rocket propulsion design, analysis, and testing for aerospace or defense applications
• Strong background in solid rocket motor design, including internal ballistics, grain design, and nozzle performance
• Experience with propulsion testing, including static fire test setup, instrumentation, and data analysis
• Familiarity with structural and thermal design considerations for high-temperature, high-pressure systems
• Skilled in CAD software (NX 8.5 or similar packages like PTC Creo, CATIA) with expertise in geometric dimensioning and tolerancing (GD&T) per ASME Y14.5-1994.
• Proficiency in analysis and modeling tools (e.g., MATLAB, Abaqus, or equivalent)
• Experience with hardware build, integration, and troubleshooting in a lab or test environment
• Strong problem-solving mindset, thriving in a fast-paced, hardware-rich, high test cadence environment

Preferred Skills and Experience

• Nonlinear FEA, including contact, material nonlinearity, or large deformation.
• Experience correlating analytical models with physical test data.
• Experience characterizing material mechanical properties in severe environments including hyperplastic materials, compression molded composites, tape-wrapped composites, etc.
• Aerospace, hypersonic, launch vehicle, spacecraft, or other high-performance flight hardware experience.
• Experience establishing engineering standards or methodologies.
• Demonstrated ability to mentor and develop engineers technically.
• Experience working with composites, coatings, finishes, and advanced manufacturing processes for common SRM nozzle components.

Additional Requirements