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.

Propulsion Engineer (Solid Rocket Motor Ballistics)

We are seeking a solid rocket motor ballistician to own the performance predictions of our motors. This position is central to our ability to deliver at speed and scale, with a strong emphasis on driving technically sound designs that meet aggressive schedule, affordability, and production goals.

Responsibilities

Design and develop rocket motor systems, including grain geometry, case structures, insulation, and nozzle assemblies.
Lead the architecture and detailed design of propulsion hardware to meet performance, structural, and thermal requirements
Perform internal ballistics, thermal, and structural analyses to ensure motor performance and reliability under extreme operating conditions
Advance the internal Castelion capabilities for analysis predictions and correlation to tests for solid rocket motor propellant as well as ignition systems (BKNO3)
Work closely with structures, thermal, GNC, and manufacturing teams to ensure seamless integration of propulsion systems with the vehicle
Support propellant selection, processing, and characterization in collaboration with materials and manufacturing teams
Plan and execute static fire tests and development test campaigns, including instrumentation, data collection, and post-test analysis
Conduct failure analysis and root cause investigations, driving design improvements and risk reduction
Define and execute qualification and flight test plans, translating results into system-level improvements
Optimize designs for performance, mass, manufacturability, and operational reliability
Mentor junior engineers and contribute to best practices in propulsion system design and testing
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
2+ 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, ignitors, 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
Proficiency in analysis and modeling tools (e.g., MATLAB, SPP, 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

Experience with preliminary / conceptual design from performance requirements for solid rocket motor grains
Experience with pyrotechnic and pyrogenic ignition systems and characterizing ignitor performance.
Experience with grain and nozzle optimization for tactical SRM systems.
Experience correlating analytical models with physical test data.
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.

Additional Requirements

Willing and able to work extended hours and/or weekends with minimal notification to meet critical deadlines leading up to major milestones.