Systems Integration & Test Engineer, Avionics (All Levels)

About Castelion

Castelion is bringing a new approach to defense development and production: one that focuses on short, iterative design cycles, rapid testing in development, and modern commercial manufacturing strategies for production at scale. We're designing, building, and testing next generation long range strike weapons systems to give America and its Allies a definitive edge and deter future conflicts.

Senior Avionics Test Engineer

We are looking for a Senior Avionics Test Engineer to own the validation and performance characterization of our control actuation systems the critical interface between control commands and physical motion on our flight vehicles. You will lead the development of rigorous test infrastructure, design and execute test campaigns, and help define the performance envelope of every actuator that flies.

This role blends hands-on testing with systems-level thinking. You'll work closely with controls, software, avionics, and mechanical teams to ensure our actuation hardware is verified against realistic, mission-representative conditions.

Responsibilities

• Develop and execute comprehensive actuator test plans across component, subassembly, and integrated system levels.

• Build test fixtures, HIL environments, and automated test rigs to simulate flight conditions and actuator load profiles.

• Validate performance metrics such as torque, response time, bandwidth, power draw, and thermal behavior under nominal and fault scenarios.

• Instrument and log actuator tests for precise characterization and traceability.

• Lead root-cause investigations for performance anomalies or test failures.

• Collaborate with mechanical and control systems teams to refine actuator designs based on test results and failure data.

• Drive qualification testing and environmental testing campaigns (vibe, thermal, EMI) for flight hardware. Basic Qualifications

• B.S. or M.S. in Mechanical, Mechatronics, Aerospace, or Electrical Engineering.

• 4+ years of experience testing actuators, servos, or motion control systems for aerospace, automotive, robotics, or defense applications.

• Strong hands-on experience designing and running test setups involving motors, load cells, encoders, and motion control loops.

• 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 with high-force/high-precision actuator systems (e.g., TVC, flight control surfaces, robotic manipulators).

• 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. What We Value

• Hands-on rigor: deep understanding of systems through direct testing and failure analysis.

• Autonomy and ownership: you don't wait for direction you seek out what needs to be tested and make it happen.

• High standards for reliability, data quality, and test repeatability.

• Systems-level thinking: understanding how actuator behavior affects broader vehicle performance. Leadership Qualities

Bias to Action and Creative Problem Solving. Desire and experience questioning assumptions in ways that lead to break through ideas that are ultimately implemented. Successfully bring in applicable processes/concepts/materials from other industries to achieve efficiency gains. Ability to personally resolve minor issues in development without requiring significant support.

High Commitment, High Initiative. A successful candidate will have a genuine passion for Castelion's mission and consistently look for ways to contribute to the company's technical goals and prevent hardware blockers. Ability to work in a fast paced, autonomously driven, and demanding atmosphere. Strong sense of accountability and integrity.

Clear Communicator. Proactively communicates blockers. Trusted in previous roles to be voice of company with regulators, suppliers, gate keepers and customers. Capable of tactfully managing relationships with stakeholders to achieve company-desired outcomes without compromising relationships. Emails, IMs and verbal interactions are logical, drive clarity, and detailed enough to eliminate ambiguity.

ITAR Requirements

• To conform to U.S. Government export regulations, applicant must be a (i) U.S. citizen or national, (ii) U.S. lawful, permanent resident (aka green card holder), (iii) Refugee under 8 U.S.C. § 1157, or (iv) Asylee under 8 U.S.C. § 1158, or be eligible to obtain the required authorizations from the U.S. Department of State. 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.

All employees are granted long-term stock incentives as part of their employment at Castelion. All employees receive access to comprehensive medical, vision, and dental insurance, and the company offers four weeks of paid time off per year.