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.

Materials Engineer – Flight Vehicle Support

Castelion is seeking a highly motivated Junior Materials & Processes (M&P) Engineer to support the development, qualification, and production of advanced materials for hypersonic flight applications. This role will focus on adhesive bond development, mechanical testing, materials characterization, and engineering documentation in support of solid rocket motors and other flight hardware.

The successful candidate will work closely with senior engineers to execute laboratory testing, analyze material performance, generate technical documentation, and support material qualification activities. This position requires strong attention to detail, hands-on laboratory skills, and a desire to develop expertise across a broad range of aerospace materials and manufacturing processes.

Responsibilities

• Prepare and test adhesive bond specimens in accordance with internal procedures and applicable ASTM standards.

• Perform materials characterization and mechanical testing in support of flight hardware and thermal protection system (TPS) development programs.

• Analyze experimental data and prepare technical reports summarizing results and recommendations.

• Generate and maintain engineering documentation including material specifications, process specifications, test plans, qualification reports, and test procedures.

• Support material failure investigations and root cause analyses.

• Work closely with design, manufacturing, and quality teams to support material selection, qualification, and production activities.

Basic Qualifications

• Bachelor's degree in Materials Science & Engineering, Mechanical Engineering, Chemical Engineering, Aerospace Engineering, or a related discipline.

Preferred Skills and Experience

• 0–3 years of engineering experience (internships or undergraduate research considered).

• Strong analytical and problem-solving skills.

• Excellent written and verbal communication skills.

• Ability to work effectively in both laboratory and cross-functional engineering environments.

Benefits And Perks

• 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

Physical Demands

• Must be willing to work extended hours and/or weekends as needed

• Must be able to travel up to 30%
• Must be able to lift more than 50lbs

ITAR Requirements

To conform to U.S. Government export regulations, applicant must be a (i) U.S. citizen or national, (ii) U.S. lawful, permanent resident (aka green card holder), (iii) Refugee under 8 U.S.C. § 1157, or (iv) Asylee under 8 U.S.C. § 1158, or be eligible to obtain the required authorizations from the U.S. Department of State.

This position may require access to classified information or restricted U.S. Government sites, systems, or information, as determined by the Company and/or applicable U.S. Government requirements. If the position is so designated, your employment in the role may be contingent upon your ability to obtain and maintain the required U.S. Government security clearance or other government authorization, and to satisfy any citizenship or other eligibility requirements imposed by applicable law, regulation, executive order, or government contract requirements. You will be notified if and when such requirements apply. Failure to obtain or maintain any required clearance or authorization may result in reassignment, leave, or separation from employment, consistent with business needs and applicable law.

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.

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.