Senior Test Engineer

About Helion We are a fusion power company based in Everett, WA, with the mission to build the world's first fusion power plant, enabling a future with unlimited clean electricity. Our vision is a world with clean, reliable, and affordable energy for everyone. Since Helion's founding in 2013, we have raised over $1 billion from long-time investors such as Sam Altman, Mithril, and Capricorn Investment Group as well as new investors SoftBank and Lightspeed to propel us forward. Our last prototype, Trenta, completed 10,000 high-power pulses and reached plasma temperatures of 100 million degrees Celsius (9 keV). We are now operating Polaris, our next prototype on the path to the world's first fusion power plant. This is a pivotal time to join Helion. You will tackle real-world challenges with a team that prizes urgency, rigor, ownership, and a commitment to delivering hard truths – values essential to achieving what no one has before. Together, we will change the future of energy, because the world can't wait. What You Will Be Doing: As a Test Engineer at Helion, you will be responsible for designing, building, and sustaining the electrical test systems that validate PCBAs, power electronics, and high-voltage assemblies used across our fusion generators. You will operate at the intersection of design engineering and production, ensuring that test infrastructure is robust, repeatable, and safe for hand-on execution by technicians. Your work will directly enable faster hardware iteration, improved first-pass yield, and reliable delivery of mission-critical electrical systems that support Helion's fusion generators and pulsed-power architecture. This is a hands-on, lab-based role reporting to the Production Manager and working closely with Design Engineers, R&D Engineers, and Technicians/Supervisors. This is onsite role located at our Everett, WA office. You Will: - Design and deliver electrical test systems for PCBA and high-voltage assemblies, including test rack architecture, fixture design, instrumentation selection, electrical integration, and supporting automation - Design test fixture PCBAs used within test racks and fixturing, owning schematic capture, layout, review, and bring-up to enable functional validation and diagnostics of production hardware - Build, wire, debug, and maintain complete test racks and fixtures, including power distribution, safety interlocks, signal routing, and data acquisition integration - Develop and maintain data acquisition and control tools using Python or PLC-based systems to support sequencing, measurement, and reporting - Write and maintain test procedures, calibration standards, and test limits in collaboration with design engineering and production leadership - Analyze test data to generate FPY, yield, and performance metrics, and partner with design teams to refine thresholds and improve robustness - Work hands-on with technicians and supervisors to standardize safe, repeatable test execution and continuously improve test system scalability and maintainability - Support deployment and sustainment of test infrastructure at Contract Manufacturers, including validation of test hardware and associated electronics Required Skills: - Bachelor’s degree in electrical engineering, Mechatronics, or a related field - 5+ years of experience developing and supporting electrical or electronic test systems in R&D or production environments - Demonstrated experience designing PCBAs for test fixtures or test systems, including schematic capture, layout, review, and bring-up - Proficiency with ECAD tools such as Altium Designer or equivalent - Strong hands-on experience designing, building, wiring, and debugging test racks, fixtures, harnesses, and control systems - Working experience with Python or PLC-based systems for test sequencing, automation, and data acquisition - Proficiency using standard lab instrumentation including oscilloscopes, DMMs, power supplies, electronic loads, and spectrum analyzers -