GNC Engineer - Actuation Systems

About the role

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.

Responsibilities

• Design, implement, and tune closed-loop control systems for flight vehicle actuators
• Develop position, velocity, force, torque, and current control architectures as required by the actuator system
• Model electromechanical actuator dynamics, including motors, transmissions, ball screws, control surfaces, sensors, structural loads, friction, backlash, saturation, and other nonlinear effects
• Develop actuator performance requirements and support motor, gearing, sensor, and mechanical hardware sizing
• Perform stability, bandwidth, robustness, disturbance rejection, and tracking performance analysis
• Develop feedforward, filtering, compensation, anti-windup, command shaping, and other control features to improve actuator performance
• Perform system identification and parameter estimation using component, bench, and integrated test data
• Build actuator models for high-fidelity vehicle and 6-DOF simulations
• Implement control algorithms in embedded flight software and support real-time execution constraints
• Develop Software-in-the-Loop (SITL) and Hardware-in-the-Loop (HITL) test environments for actuator validation
• Plan and execute hardware characterization and closed-loop actuator testing
• Analyze test and flight data to validate models, identify performance limitations, and improve control designs
• Work closely with GNC, avionics, embedded software, mechanical, electrical, and test engineers to deliver integrated flight-ready actuation systems

Qualifications

• Bachelor's degree in Aerospace Engineering, Mechanical Engineering, Electrical Engineering, Computer Engineering, or a related technical field
• Strong fundamentals in feedback controls, dynamics, or electromechanical systems
• Experience programming in Python, Rust, C/C++, Julia, or a similar technical computing language
• Experience analyzing dynamic systems through coursework, research, internships, projects, or professional work
• Ability to work effectively across software, electrical, mechanical, and controls disciplines
• Ability to obtain and maintain a U.S. government–issued security clearance (U.S. citizenship required)

Skills

• Experience designing and tuning closed-loop control systems for electromechanical or aerospace hardware
• Experience with motor control, servo systems, position control, velocity control, force control, or torque control
• Experience modeling DC, BLDC, or PMSM motors and their associated drive electronics
• Experience with mechanical transmission systems such as gearboxes, ball screws, linkages, or rotary-to-linear mechanisms
• Strong understanding of classical control techniques, including loop shaping, gain and phase margin, bandwidth, and frequency-domain analysis
• Experience with state-space controls, observers, feedforward control, or disturbance estimation
• Experience with nonlinearities including saturation, rate limits, deadband, backlash, friction, hysteresis, and compliance
• Experience with system identification and correlation of analytical models against hardware test data
• Experience with embedded or real-time control software
• Experience with sensors such as encoders, resolvers, current sensors, load cells, or position transducers
• Experience with actuator sizing, power requirements, thermal constraints, structural loads, or performance trades
• Experience developing simulation models for actuator dynamics and integrating them into larger vehicle simulations
• Experience with Monte Carlo analysis, uncertainty analysis, or robustness assessment
• Experience with Software-in-the-Loop (SITL) or Hardware-in-the-Loop (HITL) testing
• Experience designing or operating test stands and working directly with flight-like hardware
• Experience supporting aerospace, robotics, automotive, industrial automation, or other high-performance motion-control systems

Benefits

• All full-time employees are granted meaningful long-term equity, sharing in the company's significant growth trajectory
• Four (4) weeks of paid time off
• Ten (10) company-paid holidays
• Comprehensive health benefits – including 100% employee-covered medical and strong dependent coverage, along with dental and vision plans
• Paid parental leave to support growing families
• $100 monthly fitness stipend to promote health and performance
• Onsite EV charging for convenience
• Catered meals, company-covered food during high-demand periods, and a fully stocked kitchen to stay fueled throughout the day