Senior Propellant Analyst Torrance, CA Flight Sciences

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.

We're looking for a Senior Propellant Analyst to support the design, development, and qualification of solid rocket motors for next-generation hypersonic defense systems. You'll work in a fast-moving startup environment where your analysis directly informs propellant formulation, grain design, and motor performance predictions. This role offers high ownership, close collaboration with manufacturing and test teams, and the opportunity to see your work rapidly turn into flight-ready hardware.

• Conduct structural and stress analysis of propellant grains, including case-bonded configurations, under mechanical, thermal, and pressure loading.
• Use analytical methods, finite element analysis, and specialized propulsion software to evaluate grain geometry, pressure-time profiles, and structural integrity.
• Work closely with motor design engineers and manufacturing teams to influence grain geometry, propellant formulation, and case design early in the development process.
• Support propellant grain qualification activities, including aging studies, thermal cycling, and flight readiness assessments.
• Exemplify technical excellence and be accountable for your work.
• Communicate technical content efficiently and effectively to partner teams.

• Bachelor's degree in Aerospace Engineering, Mechanical Engineering, Chemical Engineering, or a related field.
• 5+ years of experience in propellant grain analysis, solid rocket motor design, or related propulsion disciplines.
• Strong understanding of propellant grain structural mechanics.
• Experience with finite element analysis tools (Abaqus, NASTRAN, ANSYS) for propellant grain stress analysis.
• Comfortable working in ambiguous, rapidly evolving technical environments.

• Master's degree or PhD in Aerospace Engineering, Mechanical Engineering, or Chemical Engineering.
• Direct experience with tactical or strategic solid rocket motor programs.
• Knowledge of propellant failure modes, including debonding, cracking, and aging effects.
• Experience with viscoelastic material modeling and time-temperature-dependent propellant behavior.
• Familiarity with DoD solid rocket motor standards and qualification processes (e.g., MIL-STD-1751, MSFC-SPEC-522).
• Hands-on experience supporting static fire testing, motor instrumentation, or propellant manufacturing processes.

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

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.

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.

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…