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 and technical excellence are decisive advantages - and we are building a team that can deliver real capability, not just concepts.

This is a rare opportunity to join at an early stage, where your work will directly shape critical systems, influence major technical decisions, and have immediate, real-world impact.

Senior Thermal & TPS Integration Engineer

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.

Responsibilities

• Design and develop TPS across the vehicle, including heat shields, acreage TPS, and leading-edge protection systems
• Design TPS for control surfaces, including elevons, seals, and moving interface solutions that maintain performance under thermal and mechanical loads
• Develop internal thermal protection solutions, including insulators, blankets, and standoff systems to protect avionics and structures
• Lead the architecture and integration of TPS with primary structure, mechanisms, and subsystems, including attachment methods, gaps, and strain isolation
• Perform thermal and thermal-structural analyses to ensure performance under extreme aerothermal heating and transient environments
• Work closely with structures, materials, aerothermal, GNC, and manufacturing teams to ensure seamless system integration
• Develop and evaluate materials and configurations, including ceramics, carbon-carbon, ablatives, and insulating materials
• Conduct tolerance analysis and assess thermal expansion, deformation, and interface behavior
• Support prototyping, assembly, and hardware bring-up, including troubleshooting and root cause analysis of TPS performance issues
• Define and execute qualification and environmental test plans, including arc-jet, furnace, and flight testing
• Optimize designs for mass, thermal performance, durability, and manufacturability
• Mentor junior engineers and contribute to best practices in TPS design and integration
• 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, 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

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.

Benefits And Perks

All full-time employees are granted meaningful long-term equity, sharing in the company's significant growth trajectory. We offer four (4) weeks of paid time off, ten (10) company-paid holidays, and comprehensive health benefits - including 100% employee-covered medical and strong dependent coverage, along with dental and vision plans. We also provide paid parental leave to support growing families, a $100 monthly fitness stipend to promote health and performance, and onsite EV charging for convenience. In addition, employees enjoy perks like catered meals, company-covered food during high-demand periods, and a fully stocked kitchen to stay fueled throughout the day.

While this position does not currently require a U.S government-issued security clearance, it may in the near future. Therefore, the ability to obtain and maintain a U.S. government–issued security clearance is required. U.S. citizenship is required, as only U.S. citizens are eligible for a security clearance.

Affirmative Action/EEO Statement

Employment with Castelion is governed on the basis of competence and qualifications and will not be influenced in any manner by race, color, religion, gender, national origin/ethnicity, veteran status, disability status, age, sexual orientation, gender identity, marital status, mental or physical disability or any other legally protected status.