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 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.

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 involve