GNC Engineer

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. GNC Engineer As a GNC Engineer at Castelion, you will build the algorithms, models, and software that make our vehicles fly. You will work across guidance, navigation, flight controls, and high-fidelity simulation to solve difficult problems in high-speed flight. Depending on your strengths and interests, you may focus deeply in one area or work across several. You will take ideas from analysis and simulation through software, hardware testing, and flight. This role is ideal for engineers who want broad ownership, hard technical problems, and a direct connection between their work and vehicle performance. Responsibilities • Develop and tune flight control algorithms for stability and performance across a challenging flight envelope • Develop guidance algorithms for trajectory shaping and mission execution • Develop navigation and state estimation algorithms • Model and analyze actuation systems, including aerodynamic control surfaces and electromechanical actuators • Build and improve high-fidelity 6-DOF simulations of vehicle flight • Model vehicle dynamics, aerodynamics, propulsion, sensors, actuators, and environmental effects • Implement and test GNC algorithms in flight software • Support Monte Carlo, Software-in-the-Loop (SITL), and Hardware-in-the-Loop (HITL) test environments • Support vehicle sizing, performance analysis, and hardware requirements • Support flight test planning, prediction, execution, and post-flight analysis • Use simulation, hardware, and flight data to improve models and vehicle performance Basic Qualifications • Bachelor's degree in Aerospace Engineering, Mechanical Engineering, Electrical Engineering, Computer Engineering, or a related technical field • Familiarity with aerodynamics, flight dynamics, and rigid-body dynamics • Strong fundamentals in dynamics, controls, estimation, numerical methods, or simulation • Strong programming skills in Rust, C/C++, Python, Julia, or a similar language • Demonstrated ability to solve technical problems through coursework, research, internships, projects, or professional experience • Ability to communicate technical results clearly and work effectively with multidisciplinary engineering teams Preferred Skills and Experience • Experience with flight controls, guidance, navigation, estimation, actuation, or vehicle simulation • Experience designing or analyzing feedback control systems • Experience with Kalman filtering, sensor fusion, or inertial navigation • Experience with trajectory optimization, guidance, or optimal control • Experience building 6-DOF or other nonlinear dynamic simulations • Experience modeling or controlling electromechanical or aerospace actuation systems • Experience with embedded or real-time software • Experience with Monte Carlo analysis, uncertainty analysis, or model validation • Experience with SITL or HITL testing • Experience analyzing test or flight data • Hands-on experience with rockets, UAVs, robotics, Formula SAE, research vehicles, or other complex hardware systems 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.