Systems Test 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. Systems Test Engineer We are looking for a Systems Test Engineer to own the test requirements, automated test station development, integration, validation and performance characterization. In this role, you will take end-to-end ownership for test equipment deployment in hardware domains such as Control Actuation System (CAS), Ignition Safety Devices (ISDs), thrust vector control systems, Flight Avionics electronics, and other instrumentation circuit boards and sub-assemblies. You will lead the development of rigorous test infrastructure, design and execute test campaigns, and help define the production test performance envelope from components to circuit boards, to sub-systems. This role blends hands-on testing with systems-level thinking. You'll work closely with controls, software, avionics, and mechanical teams to ensure our avionics hardware is verified against realistic, mission-representative conditions. Responsibilities • Develop and execute comprehensive test plans across component, subassembly, and integrated system levels. • Design & Build test fixtures, HIL environments, and automated test rigs to provide test conditions and automated test profiles. • Validate performance metrics such as power consumption, digital communication, RF performance, torque, response time, bandwidth, and thermal/vibe behavior under nominal and fault scenarios. • Instrument and log tests for precise characterization and traceability. • Lead root-cause investigations for performance anomalies or test failures. • Collaborate with flight hardware development to refine designs based on test results and failure data. • Drive qualification testing and environmental testing campaigns (vibe, thermal, EMI) for flight hardware. • Deploy and prove test equipment designs for components, CCA, and sub-assembly test stations. Basic Qualifications • B.S. or M.S. in Mechanical, Mechatronics, Aerospace, or Electrical Engineering. • Experience testing high power sub-assemblies, high-speed digital interfaces, actuators, motion control systems, and RF sub-assemblies for aerospace, automotive, robotics, or defense applications. • Hands-on experience designing automated test equipment from the ground up utilizing equipment such as power suppliers, DMMs, oscilloscopes, switch matrixes, network analyzers, spectrum analyzers, signal generators, electronic loads, etc. • Familiarity with embedded control systems and communication protocols (CAN, RS-422/485, SPI, Ethernet, Automotive Ethernet). • Proficient in using instrumentation and data acquisition systems (e.g., Python, C++,Protobuffs, custom scripts) • Demonstrated ability to work independently and lead multi-disciplinary integration efforts. Preferred Skills and Experience • Experience in RF testing fundamentals or more advanced knowledge of Radar architecture • Experience with software development for test automation for digital, power, and RF electronics (Python preferred) • Experience controlling test instrumentation using SCPI, VISA, or PyVISA commands • Experience developing GUIs or dashboards • Experience in writing custom scripts for data analysis & database creation • Experience writing software for Environmental Chambers and/or RF Chambers • Exposure to flight-like test environments, including environmental stress screening (ESS) • Experience with fault injection, failure mode testing, and reliability qualification for mission-critical systems • Working knowledge of C/C++ or Python for custom test tooling or embedded systems debugging • Background supporting flight test or launch operations. 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.