About Castelion

Castelion is bringing a new approach to defense development and production: one that focuses on short, iterative design cycles, rapid testing in development, and modern commercial manufacturing strategies for production at scale. Were designing, building, and testing next generation long range strike weapons systems to give America and its Allies a definitive edge and deter future conflicts.

Manufacturing Engineer - Propellant Mixing & Casting

Castelion is building the next generation of defense hardware and is looking for a motivated early-career Manufacturing Engineer to join our solid rocket motor production team in Midland, TX. In this hands-on role, you will support the development, qualification, and daily execution of safe and repeatable propellant mixing, vacuum casting, and curing.

Key Responsibilities

• Assist in the day-to-day execution of propellant mixing, vacuum casting, and curing operations following established procedures and safety protocols.
• Support process development by running small-scale mixing trials, collecting rheology and temperature data, and documenting results.
• Help troubleshoot common casting defects (voids, cracks, unbonded areas) by performing root-cause analysis with guidance from senior team members.
• Participate in continuous improvement projects focused on yield improvement, cycle-time reduction, and waste elimination.
• Operate and maintain mixing equipment, vacuum systems, ovens, and basic inspection tools.
• Contribute to the creation and revision of standard operating procedures (SOPs), work instructions, and process control documentation.
• Support scale-up activities by helping specify fixtures, tooling, and layout improvements for higher-rate production.
• Work closely with Quality Assurance, EHS (Environment, Health & Safety), and senior engineers on non-conformance investigations and corrective actions.
• Assist in new product introduction (NPI) tasks such as qualification casting runs, PFMEA updates, and basic non-destructive evaluation (NDE).
• Maintain accurate records in the Manufacturing Execution System (MES) and help implement simple data-collection or automation scripts when needed.

Required Qualifications

• Bachelors degree in Chemical Engineering, Mechanical Engineering, Aerospace Engineering, Materials Science, or a closely related discipline.
• 03 years of relevant experience (co-op, internship, or academic research projects involving process engineering, composites, or energetics strongly preferred).
• Strong foundational knowledge of chemistry and materials science (coursework or projects involving polymers, composites, or reaction kinetics is a plus).
• Hands-on experience in a laboratory or manufacturing setting (academic labs, senior design projects, internships, or personal projects count).
• Familiarity with basic safety practices in chemical or energetic material environments.
• Comfortable working with hand tools, data acquisition systems, and basic test equipment.
• Excellent attention to detail and ability to follow strict procedures.
• Strong written and verbal communication skills.

Preferred Skills

• Any prior exposure to composite propellants, vacuum casting, rheology, or energetic materials (even academic or hobby rocketry experience).
• Basic scripting or data analysis skills (Python, MATLAB, Excel VBA, or LabVIEW).
• Experience reading technical drawings and CAD models.
• Enthusiasm for defense technology and willingness to work in a regulated, high-safety environment.

Leadership Qualities

• Bias to Action and Creative Problem Solving. Desire and experience questioning assumptions in ways that lead to break through ideas that are ultimately implemented. Successfully bring in applicable processes/concepts/materials from other industries to achieve efficiency gains. Ability to personally resolve minor issues in development without requiring significant support.
• High Commitment, High Initiative. A successful candidate will have a genuine passion for Castelion's mission and consistently look for ways to contribute to the company's technical goals and prevent hardware blockers. Ability to work in a fast paced, autonomously driven, and demanding atmosphere. Strong sense of accountability and integrity.
• Clear Communicator. Proactively communicates blockers. Trusted in previous roles to be voice of company with regulators, suppliers, gate keepers and customers. Capable of tactfully managing relationships with stakeholders to achieve company-desired outcomes without compromising relationships. Emails, IMs and verbal interactions are logical, drive clarity, and detailed enough to eliminate ambiguity.

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.

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.

All employees are granted long-term stock incentives as part of their employment at Castelion. All employees receive access to comprehensive medical, vision, and dental insurance, and the company offers four weeks of paid time off per year.