Senior Mechanical Design Engineer

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. Senior Mechanical Design Engineer Castelion is seeking a high output Senior Mechanical Design Engineer with a full stack, Responsible Engineer mindset and experience shipping flight hardware. This person will be responsible for critical flight structures and mechanism design and build efforts for Castelion's hypersonic vehicles. The Senior Mechanical Design Engineer will work closely with a fast-moving team of peers and engineering leadership to ensure mission-critical hardware is delivered on time and meets demanding technical performance. A successful candidate will have significant experience delivering high-performance, mass-constrained hardware in a rapid development environment. Responsibilities Design and Deliver Mission-Critical Hardware: Lead the design, build, and integration of key flight vehicle components such as composite tanks, separation mechanisms, actuators, and control surfaces. Own your systems from concept to flight. Apply fundamentals in statics, dynamics, and modal analysis to justify designs and prove them in test and flight. Drive High-Cadence Design Iteration: Support iterative prototyping cycles every four weeks for key subsystems. Engage in cross-functional design reviews, integrate test feedback rapidly, and evolve hardware through fast-paced learning loops. Build and Maintain Engineering Rigor: Contribute to the development of engineering best practices at Castelion, including CAD standards, documentation practices, and hardware management protocols. Write build documentation and collaborate hands‑on with technicians during integration and assembly. Basic Qualifications Educational Background : Bachelors degree in Mechanical Engineering with 5+ years of professional ME experience. Technical Skills : This role requires broad mechanical domain knowledge, including detailed CAD design of complex parts, tolerance stack up analysis, thermal analysis, structural analysis, and design-to-cost. Flight-Ready Hardware : Experience designing elegant, manufacturable components optimized for weight, cost, and simplicity; familiarity with coatings, finishes, and composite structures. Full-Cycle Development Ownership : Experience bringing hardware designs from initial concept to implementation, production, and successful operations. Ability to maximize speed and value from vendors for company goals during vendor visits or joint development efforts. 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. #J-18808-Ljbffr