Senior Mechanical Engineer, Thermal

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: You will own thermo‑mechanical hardware designs for Helion's fusion generator. You will solve multidisciplinary engineering problems that are necessary for deploying fusion energy to the world and act as a culture driver on a growing team. You will report to the Senior Manager of Engineering, and this is an onsite role located at our Everett, WA office. You Will: Own and understand designs related to thermal, fluids, and structural subsystems – and improve their requirements. Learn from historical engineering approaches, design novel hardware, and test your solutions. Design fusion hardware within 3D CAD software (e.g. NX). Perform analysis (1D, 2D, 3D) with in-house and out‑of‑house tools (e.g. ANSYS) and hold design reviews to gather feedback and iterate to a fully functioning system. Learn from experts to expand your engineering skillset and domain knowledge. Work hands‑on alongside experienced technicians to implement your hardware designs. Troubleshoot hardware issues as they arise on integrated fusion generators. Required Skills: Bachelor's degree in engineering. 7+ years of professional experience delivering on full‑scope engineering projects (including schedule ownership). Experience applying engineering first‑principles and method‑based thinking to challenging problems. Hands‑on exposure to a variety of engineering disciplines (fluids, mechanical, thermal). Advanced experience with CAD software (e.g., NX, Solidworks). Benefits Our total compensation package includes benefits, including but not limited to: Medical, Dental, and Vision plans for employees and their families. 31 Days of PTO (21 vacation days and 10 sick days). 10 Paid holidays, plus company‑wide winter break. Up to 5% employer 401(k) match. Short term disability, long term disability, and life insurance. Paid parental leave and support (up to 16 weeks). Annual wellness stipend. Helion is an equal opportunity employer and value diversity at our company. We do not discriminate based on race, religion, color, national origin, gender, sexual orientation, age, marital status, veteran status, or disability status. If you need assistance or an accommodation during the interview process, please let us know. #J-18808-Ljbffr Fusion Energy Base