Castelion was founded to restore America’s ability to field advanced weapons at speed and scale. Inspired by the engineering urgency of the WWII and Apollo eras, we combine rapid iteration, vertical integration, and scalable manufacturing to deliver affordable, high-performance strike systems. Our mission: rebuild industrial agility to strengthen national security and outpace evolving threats.

About the Role:

We are seeking multiple Senior Thermal & TPS Integration Engineers to design and deliver thermal protection solutions for Castelion's long-range hypersonic strike vehicles. These roles are critical to ensuring vehicle survivability and performance in extreme aerothermal environments. You will work hands-on with multidisciplinary engineering teams to design, analyze, build, and validate TPS across the vehicle, including heat shields, control surface protection, and internal thermal insulation systems in a fast-paced, hardware-driven environment.

Requirements

Bachelor's, Master's, or PhD in Aerospace Engineering, Mechanical Engineering, Materials Science, or related field
5+ years of experience in thermal protection system design, analysis, and validation for aerospace or high-temperature applications
Strong background in aerothermal environments, heat transfer, and high-temperature materials
Experience designing TPS for flight vehicles, including heat shields, control surfaces, or internal insulation systems
Familiarity with TPS materials such as ceramics, carbon-carbon, ablatives, and insulating blankets
Experience with seals, gaps, and interface design in high-temperature, moving or constrained systems
Proficiency in thermal and structural analysis tools (e.g., ANSYS, MATLAB, or equivalent)
Experience with high-temperature testing methods (e.g., arc-jet, furnace, or similar)
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

Benefits

Employee Equity: Meaningful equity for all full-time employees - share value has increased 150x in three years
Personal Time Off: Four (4) weeks of paid time off to unplug, reset, and come back sharp—velocity matters, burnout doesn't
Company Paid Holidays: Ten (10) company paid holidays
Medical: We offer plans at 100% employee covered and 80% of dependent coverage
Dental & Vision: We cover 90% employees and 80% for dependents to ensure you and your family have access to quality preventive and ongoing care
FSA/HSA: To support long-term health and financial resilience, we offer FSA and HSA options that allow employees to set aside pre-tax dollars for eligible medical and dependent care expenses
Retirement: 401k plan offered to support long term financial growth along side high-impact, high-velocity work
Paid Parental Leave: We support growing families with meaningful time to bond and recover. Birthing parents are eligible for up to 10 weeks of paid leave, while non-birthing parents may take up to 4 weeks of paid leave. This time can be used for pre-natal care, pregnancy, childbirth, and related medical needs—ensuring every parent has the support they need during this important life moment.8-weeks of paid parental leave for all parents. Additional paid pregnancy leave for CA employees
Meals & Catering: Frequently catered lunches and team meals, plus company-covered meals when extra time or effort is required
Snacks & Beverages: Fully stocked kitchen with unlimited snacks and drinks to keep you fueled throughout the day
Performance & Fitness: $100 monthly fitness stipend to support peak performance and health, both inside and outside of work
EV Charging: Onsite electric vehicle charging available for employees

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