Senior GNC Engineer

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.

As a Senior GNC Engineer at Castelion, you will be at the forefront of developing and refining the control systems that guide and control our advanced missile systems. You will be responsible for controlled flight of development vehicles, focusing on aerodynamically efficient flight paths. This position offers the opportunity to work on cutting‑edge technology, creating advanced flight control algorithms while validating simulation models through real‑world testing.

You will collaborate closely with cross‑functional engineering teams to deliver accurate flight predictions, drive hardware specification, and conduct successful flight tests.

• 6 DOF Simulations: Build, maintain and run multi‑DOF simulations for multi‑stage vehicle flights. Implement the simulation models in Software in the Loop (SITL) systems and transition them to hardware environments. Build a validation workflow for each controller release and integrate with Hardware in the Loop (HITL) systems to test real‑world expected performance.
• Aerodynamic Analysis: Estimate, generate, and calibrate aerodynamic tables and responses. Test and validate aerodynamic performance through flight tests, novel testing, and analytical CFD or Missile DATCOM.
• Electromechanical Actuators: Develop and characterize actuator simulation models based on test data. Specify performance requirements for sensors and mechanisms from a bottom‑up approach. Quantify the impact of sensor and mechanism errors on overall performance.

• Roll‑Pitch Controlled Single Stage Flights: Design and implement initial control systems to achieve roll‑stabilized pitch controlled ballistic paths. Capture flight data to validate simulations and predict aerodynamic performance.
• Roll‑Pitch Flight Path on Multi‑Stage Vehicles: Expand controllers to multi‑stage vehicle while ensuring stable and safe flight envelopes throughout all flight regimes.
• Simulations and Model Predictions: Build and utilize simulations to inform design trades. Specify bandwidth, slew rate, limits, and output sensor requirements for navigation and control.

• Bachelor’s or Master’s degree in Aerospace Engineering, Mechanical Engineering, Electrical Engineering, or a related field.
• 5+ years of experience in GNC engineering or a similar role in the aerospace, defense, or missile systems industry.
• Experience with 6 DOF simulation tools and building flight models for missile systems.
• Familiarity with CFD, Missile Datcom, and other aerodynamics simulation tools.
• Proficient in implementing and testing Software in the Loop (SITL) systems.
• Strong programming skills in MATLAB, Python, C++, or similar languages.

• Experience with Hardware in the Loop (HITL) systems.
• Familiarity with Kalman filters for state estimation and advanced control techniques.
• Strong understanding of aerodynamics, flight dynamics, and control theory.
• Hands‑on experience with electromechanical actuator characterization and building actuator simulation models.

• Ability to put in extended hours, including evenings and weekends, when required to meet aggressive timelines.
• This role is based in Torrance, CA and requires full‑time onsite presence.

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.

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…