Manufacturing Engineer, Propellant

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, ownership, and excellence are decisive advantages - and we're building a world-class team to turn bold ideas into real capability. This is a rare opportunity to join at an early stage, where you'll have significant ownership, collaborate with exceptional teammates, and make a direct, measurable impact on our mission and the future of the company - regardless of your function. Manufacturing Engineer, Propellant We are seeking a Propellant Manufacturing Engineer to lead and execute propellant manufacturing processes for solid rocket motors (SRM) supporting Castelion's hypersonic strike programs, including Blackbeard. This role focuses on the development, optimization, qualification, and scaling of propellant formulation, mixing, casting, curing, and related processes. You will work hands-on with energetic materials in a high-consequence environment, driving process reliability, yield, safety, and throughput as we transition from prototype and research builds to high-rate production. Partnering closely with Propulsion Design, Manufacturing, Quality, Automation & Controls, and Test teams, you will ensure propellant processes meet stringent performance, safety, and producibility requirements. Responsibilities • Own or lead propellant manufacturing processes, including ingredient preparation, batch mixing, vacuum casting, grain forming, curing, and finishing operations. • Develop, document, and continuously improve process parameters, work instructions, and control plans for propellant production. • Execute Design for Manufacturability (DFM) and process FMEA activities; drive statistical process control (SPC) and yield improvement initiatives. • Support new product introduction (NPI) by translating propellant formulation and grain design requirements into robust, scalable manufacturing processes. • Perform root-cause analysis and implement corrective/preventive actions for process deviations, defects, or quality issues. Collaborate with Automation & Controls teams to introduce or improve mixing, casting, and handling automation while maintaining strict safety and process control. • Ensure full compliance with energetic materials handling protocols, DoD 4145.26-M, ATF regulations, ITAR, and site-specific explosive safety standards. • Support equipment selection, qualification, maintenance, and process validation for mixers, casting systems, ovens, and related tooling. • Interface with suppliers on propellant ingredients and intermediate materials; contribute to incoming quality and supplier process improvements. • Mentor junior engineers and technicians; contribute to training programs and process standardization across production sites. • Support facility ramp and capability expansion at the Midland, TX operations and Project Ranger campus in New Mexico. Basic Qualifications • Bachelor's or Master's degree in Chemical Engineering, Materials Science, Manufacturing Engineering, Mechanical Engineering, or related technical field. • 5+ years of manufacturing or process engineering experience, with at least 3+ years hands-on work involving solid propellants, energetic materials, or analogous high-hazard chemical/process manufacturing. • Demonstrated experience developing or scaling mixing, casting, or similar batch/process operations in a regulated environment. • Hands-on experience with propellant or energetic mixing (planetary, vertical, or similar mixers), vacuum casting, and curing processes. • Strong understanding of propellant rheology, ingredient interactions, process sensitivity, and quality attributes (density, voids, mechanical properties, ballistic performance). • Proficiency with process documentation, statistical tools (Minitab or similar), PFMEA, and root-cause methodologies. • Familiarity with process equipment design/qualification, instrumentation, and data collection for batch processes. • Working knowledge of energetic materials safety, hazardous location requirements, and large-scale chemical handling practices. • Ability to interpret engineering drawings, specifications, and material data sheets. Preferred Skills and Experience • Direct experience manufacturing solid rocket motor propellants for DoD, NASA, or commercial space/hypersonic programs. • Background in fast-paced aerospace or defense production environments (startups or primes). • Experience scaling processes from laboratory/prototype to low-rate or high-rate production. • Familiarity with insensitive munitions practices, motor case interfaces, or propellant-to-liner bonding processes. • Prior involvement in facility stand-up, equipment commissioning, or production ramp of energetic materials lines. • Experience with ITAR-controlled programs and classified manufacturing environments. Castelion offers a generous benefits package. Please refer to the bottom of our Careers page for more details. 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. Additional Eligibility Requirements 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. Affirmative Action/EEO Statement Castelion is an Equal Opportunity Employer. We are committed to providing equal employment opportunities to all applicants and employees without regard to race, color, religion, sex, sexual orientation, gender identity, national origin, age, disability, genetic information, protected veteran status, or any other characteristic protected by applicable federal, state, or local law. Castelion is committed to providing reasonable accommodations to qualified individuals with disabilities throughout the application and hiring process. If you require a reasonable accommodation to complete an application, participate in the interview process, or otherwise participate in the hiring process, please contact hr@castelion.com. Requests for accommodation will be considered on an individual basis and handled in accordance with applicable law. Castelion is committed to fostering a workplace where employment decisions are based on qualifications, business needs, and the ability to perform the essential functions of the role, with or without reasonable accommodation. EAR/ITAR Requirements This position requires access to export-controlled information, and as such, employment (or hiring of a contractor) is contingent upon the candidate’s ability to access all applicable export-controlled information without additional export licensing being required by the Bureau of Industry and Security and/or the Directorate of Defense Trade Controls.