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.

Senior GNC Engineer

We are seeking a Senior GNC Engineer to develop guidance, navigation, and control solutions for Castelion's long-range hypersonic strike vehicles. This role is critical to enabling stable, precise, and adaptive flight performance across all mission phases. You will work hands-on with multidisciplinary engineering teams to design, analyze, implement, and validate control and autopilot algorithms in a fast-paced, hardware-driven environment.

Responsibilities

• Design and develop flight control and autopilot algorithms for high-speed flight vehicles across atmospheric and exo-atmospheric regimes
• Develop and implement advanced control strategies, including adaptive and robust control methods, to ensure performance under uncertain and dynamic conditions
• Conduct modeling, simulation, and analysis (3DOF/6DOF) to evaluate control system performance, stability, and robustness
• Work closely with avionics, flight sciences, mechanisms, and flight software teams to integrate control algorithms into real-time embedded systems
• Support hardware-in-the-loop (HIL) testing, flight testing, and post-flight analysis, translating results into system-level improvements
• Analyze vehicle dynamics, actuator behavior, and sensor characteristics to inform control system design and tuning
• Develop tools and frameworks for control system design, verification, and validation
• Mentor junior engineers and contribute to best practices in GNC and control system development
• Partner closely with program leadership to make technical trades aligned with mission success

Basic Qualifications

• Bachelor's, Master's, or PhD in Aerospace Engineering, Electrical Engineering, or related field
• 5+ years of experience in control system design, analysis, and validation for aerospace or high-performance dynamic systems
• Strong background in classical and modern control theory, including adaptive, nonlinear, and robust control methods
• Experience developing autopilot algorithms for missiles, rockets, hypersonic vehicles, or similar systems
• Proficiency in modeling and simulation tools such as MATLAB/Simulink or equivalent
• Experience with 3DOF and 6DOF simulation environments and real-time control implementation
• Familiarity with flight software integration and real-time embedded systems
• Strong problem-solving mindset, thriving in a fast-paced, hardware-rich, high flight cadence environment

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.

Benefits And Perks

All full-time employees are granted meaningful long-term equity, sharing in the company's significant growth trajectory. We offer four (4) weeks of paid time off, ten (10) company-paid holidays, and comprehensive health benefits - including 100% employee-covered medical and strong dependent coverage, along with dental and vision plans. We also provide paid parental leave to support growing families, a $100 monthly fitness stipend to promote health and performance, and onsite EV charging for convenience. In addition, employees enjoy perks like catered meals, company-covered food during high-demand periods, and a fully stocked kitchen to stay fueled throughout the day.

While this position does not currently require a U.S government-issued security clearance, it may in the near future. Therefore, the ability to obtain and maintain a U.S. government–issued security clearance is required. U.S. citizenship is required, as only U.S. citizens are eligible for a security clearance.

Affirmative Action/EEO Statement

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.