Materials Engineer - Chemist

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 chemist to support development and scale-up of a proprietary wet chemistry process that is central to production of next-generation aerospace materials. This role is ideal for an individual interested in reaction development, process optimization, and translating laboratory-scale chemistry into robust manufacturing processes.

The role combines hands‑on laboratory chemistry with analytical process development responsibilities. The chemist will execute and optimize multi‑step chemical syntheses, characterize reaction products, develop standardized operating procedures, and support the transition of the process from laboratory‑scale production to increasingly larger manufacturing systems.

• Execute and monitor multi-step wet chemistry synthesis processes to support development and production activities.
• Design and perform experiments to optimize reaction conditions, yields, purity, and process repeatability using structured experimental methodologies.
• Characterize reaction intermediates and final products using standard analytical laboratory techniques.
• Collect, organize, and analyze process and analytical data to support process optimization and manufacturing readiness.
• Develop and maintain process documentation, work instructions, batch records, and standardized operating procedures.
• Troubleshoot reaction, purification, and process issues in a fast‑paced development environment.
• Support scale‑up activities by evaluating reaction performance across increasing batch sizes and implementing process improvements to enable future production capacity.

• Bachelor's or Master's degree in Chemistry, Chemical Engineering, Polymer Chemistry, Organic Chemistry, or a related field.
• 1+ years of wet chemistry synthesis experience

• Experience with wet chemistry processing, hazardous chemical handling, and laboratory-scale synthesis.
• Familiarity with standard analytical characterization techniques (e.g., GC, GC-MS FTIR, NMR, Chromatography, DSC, TGA, or equivalent).
• Strong experimental design, data analysis, and technical documentation skills.
• Ability to work independently in a hands‑on laboratory 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
• Meals & Catering:
  Frequently catered lunches and team meals, plus company‑covered meals when extra time or effort is…