ACS / GNC Engineer (Senior Levels)

York Space Systems is seeking a Senior GNC/ACS Engineer to lead the design, analysis, integration, and on-orbit support of spacecraft guidance, navigation, and attitude control systems across a range of commercial and national security missions. This individual will serve as a technical leader within the ACS team, working across multiple programs to define subsystem architecture, develop algorithms and models, support verification and flight operations, and mentor junior engineers. RESPONSIBILITIES Lead the analysis, design, and development of spacecraft attitude determination and control algorithms, simulations, and system models. Own ACS/GNC requirement decomposition, allocation, verification planning, and performance assessment from mission-level requirements through subsystem implementation. Lead trade studies for sensors, actuators, control architectures, estimation approaches, and mission-specific ACS/GNC concepts of operation. Define and maintain high-fidelity simulation environments to support design, integration, test, and mission operations. Lead software-in-the-loop, processor-in-the-loop, hardware-in-the-loop, and other integrated verification activities for ACS/GNC functionality and performance. Support spacecraft integration, test, commissioning, mission operations, and anomaly investigation using telemetry and flight data. Serve as the ACS/GNC technical interface to systems engineering, flight software, avionics, mechanical, thermal, manufacturing, and mission operations teams to ensure mission objectives are understood and supported by product design. Prepare for and present at internal and customer design reviews as an ACS/GNC subject matter expert. Provide technical direction and mentorship to junior engineers and contribute to the development of ACS team processes, standards, and best practices. Work with ACS hardware suppliers and internal supply chain teams to evaluate, select, procure, and integrate hardware needed to meet technical and programmatic objectives. QUALIFICATIONS Bachelor’s degree in aerospace engineering, mechanical engineering, electrical engineering, physics, or related technical field required; Master’s degree or PhD preferred. 4+ years of experience in spacecraft GNC/ACS development (8+ years preferred); equivalent advanced degree plus directly relevant experience may be considered. Strong background in spacecraft attitude dynamics, control theory, estimation, and system modeling. Demonstrated experience developing and analyzing ADCS/GNC algorithms for spacecraft applications. Experience with requirements development, verification, and performance validation for flight systems. Experience with MATLAB and Simulink; experience with Python, C/C++, or flight-software-adjacent development preferred. Experience supporting integrated test campaigns, mission operations, and anomaly resolution using telemetry and flight data. Demonstrated ability to lead technical work across multiple disciplines and mentor less-experienced engineers. Strong analytical, problem-solving, written, verbal, and presentation skills. Collaborative and effective in team environments. U.S. citizenship required. Must be able to obtain and maintain a U.S. security clearance.