Senior Mechanical Engineer (Vacuum Systems) (Tukwila)
About Avalanche Energy Avalanche Energy is a Washington-based startup building compact, deployable fusion systems through rapid hardware iteration. Rather than pursuing fusion as a single grid-scale outcome, Avalanche develops transportable fusion machines designed to be built, tested, and operated on short cycles, turning real hardware into steady progress. This approach enables near-term applications that demand extreme energy density and endurance—starting with fusion neutron production for radioisotope power and other defense and space uses—while advancing the underlying fusion platform. Backed by U.S. government programs and a team experienced in delivering complex systems, Avalanche is focused on building fusion that runs in the real world, not just on paper. Avalanche might be a fit for you if: You are energized by hands-on problem solving and building real hardware. You enjoy working in a lab or machine shop, fitting parts together, chasing leaks, and making stubborn systems behave. You are comfortable moving between CAD modeling, design analysis, and elbows-deep assembly and troubleshooting. You are motivated by delivering solutions to complex problems in aggressive timelines. You care about clean designs, well-toleranced parts, and systems that work reliably under real-world conditions. You take pride in hardware that performs because the fundamentals were done right. About the Role Avalanche Energy is seeking a Senior Mechanical Engineer with deep expertise in vacuum systems to design, build, and maintain the vacuum and mechanical systems that support our compact fusion devices. You will work directly on ultra high vacuum (UHV, This is a deeply hands-on role. You will be responsible for everything from CAD modeling and component selection to fabrication, assembly, testing, and troubleshooting under demanding conditions. The work centers on precision vacuum system design, structural design, thermal and high-voltage management, and integration with experimental hardware. You will be working with materials ranging from stainless steels to refractory metals and ceramics. As a senior member of the team, you will bring established vacuum engineering practices and help evaluate, refine, and improve our current approach. This is not a desk job or a simulation-first role. This is lab-centered engineering focused on getting complex vacuum and mechanical systems to work, reliably and repeatably. Responsibilities Design, build, and maintain mechanical and vacuum systems supporting fusion experiments, diagnostics, and laboratory infrastructure. Work alongside physicists and engineers to conceive, implement, and refine mechanical systems for experimental hardware, from initial concept through fabrication, assembly, and iteration. Specify, procure, fabricate, and test mechanical hardware including vacuum vessels, structural mounts, thermal interfaces, feedthroughs, and precision mechanical assemblies. Perform hands-on troubleshooting of mechanical and vacuum systems, diagnosing issues related to leaks, thermal performance, structural loading, alignment, and hardware fit-up. Support experiment operation by setting up, validating, and maintaining mechanical systems, vacuum hardware, and associated diagnostics. Provide mechanical insight into experimental results, helping interpret hardware performance, system behavior, and failure modes. Contribute to continuous improvement of lab mechanical practices, documentation, fabrication standards, and build processes. Required Qualifications B.S. degree or higher in mechanical engineering, aerospace engineering, or a closely related field. 8-12 years of post-degree experience in hands-on mechanical engineering roles, with significant focus on vacuum systems, preferably in a laboratory or experimental hardware environment. Strong command of mechanical engineering fundamentals, including structural analysis, thermal systems, fluid mechanics, and materials selection. Proficiency in 3D CAD tools (e.g., SolidWorks, CATIA, or equivalent) for design, assembly modeling, and drawing generation. Experience designing, assembling, and operating vacuum systems, including familiarity with pumping systems, gauging, and leak checking. Experience with high-vacuum or ultra-high-vacuum (UHV, defined as pressures below 10⁻⁷ torr) systems, including system design, bakeout, and troubleshooting. Demonstrated expertise in ultra high vacuum system design and best practices, including material selection, surface preparation, and cleaning protocols for UHV compatibility. Experience establishing or improving vacuum standard operating procedures. Deep familiarity with vacuum diagnostics and troubleshooting methodology, including residual gas analysis, virtual leak identification, and outgassing source identification. Experience with thermal management design, including heat transfer analysis, cooling system design, and thermal interface materials. Experience working with machine shops and fabrication processes, including tolerance specification, GD&T, and hands-on assembly of precision mechanical hardware. Comfort working directly with physical hardware in a laboratory or machine shop environment, including hands-on assembly, installation, and test. Desired Qualifications Experience designing or building hardware for laboratory experiments, research programs, or scientific instruments. Experience working with design or fabrication using ceramic materials, including MACOR or Alumina. Familiarity with plasma physics hardware or fusion-related systems, such as magnetic coils, ion sources, beam optics, or high-voltage electrical feedthroughs. Experience with precision machining or direct hands-on fabrication, including lathe, mill, or other shop equipment. Experience working with cryogenic systems, high-pressure hardware, or other mechanically demanding environments. Familiarity with FEA tools for structural or thermal analysis (e.g., ANSYS, Abaqus, or equivalent). Additional Considerations Location : Onsite required to support hands-on laboratory work and close integration with experimental teams. Sites : Tukwila or Richland, Washington. Travel : Occasional travel for equipment procurement, integration, or collaboration as needed. Schedule : Standard business hours, with flexibility during experimental campaigns or critical test periods. Benefits Excellent medical, dental, and vision benefits. 10 paid holidays and a company-wide December holiday break. Generous paid vacation and sick time. Small, tight-knit team with low barriers to action. Exposure to a wide range of challenging, hands-on engineering problems. Meaningful equity in the form of stock options. We value people of all backgrounds. We are an equal opportunity employer, and you do not need to match every listed qualification to apply. If you like being hands-on, all over the system, and making difficult hardware work in the real world, we encourage you to apply. This position may require access to export-controlled information. In order to comply with U.S. export control laws, applicants must be a “U.S. person” as defined by U.S. trade control laws (U.S. citizen, lawful permanent resident, or protected individual).
