Materials Engineer - Temperature Composites

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.

Castelion is seeking a highly motivated recent graduate or early-career engineer to support R&D development and scale-up of our ceramic matrix composite (CMC) fabrication processes. This role will support composite layup and densification operations which are part of the production workflow for high-performance thermal protection system (TPS) materials.

The position is ideal for a recent graduate with an interest in ceramic matrix composite material process development and scaling large-scale production systems of high-performance aerospace parts. It will involve hands‑on composite fabrication work with analytical and process engineering responsibilities. The engineer will support prepreg layup and part shaping operations compression, curing, resin infiltration, and high‑temperature pyrolysis processes. In addition, the engineer will characterize fabricated materials, develop drive data collection and analysis of the different sub‑processes, and contribute to improving process repeatability and manufacturing readiness across the pilot line.

• Support composite layup, shaping, and densification operations to deliver a completed TPS demonstrator part set by the end of the year.
• Own all process QA data collection activities and database management.
• Conduct characterization activities of all finished C/SiC goods to assess performance and inform development strategies.
• Assist with prepreg layup, compression molding, filament winding, curing, resin infiltration, and pyrolysis operations for CMC components.
• Perform characterization and inspection of composite materials using standard laboratory techniques.
• Collect, organize, and analyze process and material performance data to support process optimization.
• Develop and maintain process documentation, work instructions, and standardized operating procedures.
• Support installation, maintenance, and scale‑up of pilot‑line manufacturing hardware.

• Bachelor's or Master's degree in Materials Science, Mechanical Engineering, Chemical Engineering, Aerospace Engineering, or related field.
• Familiarity with materials characterization techniques (mechanical testing, metallographic mounting and polishing, SEM).
• Must be willing to work weekends when necessary.
• Ability to work independently in a hands‑on engineering environment.

• 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
• Meal…