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.

Systems Integration & Test Engineer (Avionics)

We are looking for a Systems Integration & Test Engineer to architect and execute the full suite of hardware test capabilities needed to move our avionics and control systems from prototype to production. In this role, you will own test requirements, automated test equipment (ATE) development, integration, validation, and performance characterization across domains including power electronics, digital interfaces, RF assemblies, motion control, and flight avionics.

You will design fixtures, build automated test stations, support DVT and qualification, and define the test performance envelope for components, circuit cards, and integrated sub-systems. This role blends hands-on lab work with systems-level reasoning and close collaboration with electrical, controls, software, and mechanical engineering teams.

Responsibilities

• Develop and execute test plans at component, subassembly, and integrated system levels
• Design and build test fixtures, HIL environments, and automated test rigs
• Validate hardware performance across electrical, digital, mechanical, and RF metrics
• Instrument and log tests to ensure precision and traceability
• Lead failure analysis and root-cause investigations
• Support hardware teams by feeding test results back into design cycles
• Drive qualification and environmental test campaigns (thermal, vibe, EMI)
• Deploy and validate automated test equipment for boards and sub-systems

Basic Qualifications

• B.S./M.S. in Electrical, Mechanical, Mechatronics, Aerospace, or related
• Experience testing high-power subsystems, high-speed digital interfaces, actuators, or RF hardware
• Hands-on experience developing automated test equipment using instruments such as oscilloscopes, DMMs, power supplies, loads, switch matrices, network analyzers, etc.
• Familiarity with embedded control systems and interfaces (CAN, RS-422/485, SPI, Ethernet)
• Experience with instrumentation control and data acquisition (Python, C++, protobufs, scripting)
• Ability to work independently and lead cross-functional test integration

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

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.

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.