Senior Materials & Process Engineer, Materials Testing

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 looking for an experienced Materials Characterization Engineer to act as the main technical resource for all materials testing at the company. In this role you will be responsible for all material coupon testing to support product development and qualification efforts.

The ideal candidate brings a strong background in materials science along with hands‑on experience in mechanical testing, thermal analysis, and material characterization techniques. You should be comfortable running test hardware, interpreting test data, and working closely with cross‑functional teams to provide clear, data‑driven insights that support performance, reliability, and manufacturability.

• Own all materials coupon characterization test planning and execution for metals, composites, and bonded structures, in support of program qualification requirements and deadlines.
• Lead development and maintenance of the material property allowables database.
• Develop materials characterization lab including selection and commissioning of test hardware to improve capability, test lead-time and data quality.
• Developed internal standardized test protocols based on relevant standards (ASTM, etc.).

• Bachelor’s degree in materials engineering or a related field.
• 5+ years of experience working in materials testing, preferably within the aerospace industry.
• Must be authorized to work in the U.S. and comply with ITAR eligibility requirements.

• Strong hands‑on experience with materials characterization and sample preparation techniques (mechanical testing, hardness testing, TGA, DSC, OM, SEM/EDS, FTIR, XRD).
• Strong knowledge of material testing standards (ASTM, ISO, ASM, etc).
• Excellent written and verbal communication skills.
• 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
• 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

• Must be able to work extended hours
• Must be able to move and carry up to 25lbs

To conform to U.S. Government export regulations, applicant must be a (i) U.S. citizen or national, (ii) U.S.…