Senior Flight Mechanics 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. We're designing, building, and testing next generation long range strike weapon systems to give America and its Allies a definitive edge and deter future conflicts.

Senior Flight Mechanics Engineer

We are seeking a Senior Flight Mechanics Engineer to lead analysis and design for Castelion's long-range hypersonic strike vehicles. This role is critical in shaping the flight performance of our hypersonic systems from concept through flight tests. You will work hands-on with multidisciplinary engineering teams to design, analyze, characterize, and validate flight vehicle products in a rapid hardware-driven environment.

Responsibilities

- Lead the design and optimization of hypersonic flight vehicle shapes, airfoils, control surfaces, and controls to maximize performance, stability, and maneuverability in atmospheric and space environments

· Conduct computational fluid dynamics (CFD) and trajectory simulations to evaluate vehicle performance, identify improvement opportunities, and validate design decisions

· Develop and execute wind tunnel testing campaigns to validate aerodynamic models and optimize vehicle design

· Analyze and enhance the flight dynamics and stability of Castelion's long-range hypersonic systems, ensuring robust performance under variable environmental conditions

· Develop aerodynamic databases to support trajectory generation, guidance, navigation & control (GNC), and performance analysis

· Work closely with teams in structures, propulsion, thermal protection systems, and GNC to ensure seamless vehicle integration

· Define and execute test plans for wind tunnel, subscale, and full-scale flight tests, translating results into system-level design improvements

· Mentor and guide junior engineers in flight mechanics best practices

· Partner closely with program leadership to make technical trades aligned with mission success

Basic Qualifications

· Bachelors, Masters, or PhD in Aerospace Engineering or related field

· 5+ years of experience in flight vehicle design, analysis, and validation for high-speed vehicles (missiles, rockets, hypersonic glide vehicles, or maneuvering re-entry systems)

· Strong background in CFD, trajectory/flight simulation (3DOF and 6DOF), and wind tunnel test methods

· Experience generating and validating aerodynamic databases for use in trajectory and GNC simulations

· Familiarity with compressible flow, high-Mach regimes, and stability/control analysis

· Hands-on experience with wind tunnel testing and/or flight test programs

· Proficiency in flight/trajectory analysis tools such as TAOS, POST, or equivalent

· Strong problem-solving mindset, thriving in a fast-paced, hardware-rich environment

Why Castelion

· Opportunity to shape the design of cutting-edge high-speed missile and flight systems

· Work alongside a team of A+ players who believe in the mission and want to make a difference

· Be part of a rapidly growing startup where your impact is direct and visible

· Competitive compensation, equity, and benefits package

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

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.