Senior Mechanical Engineer - Vacuum Systems

About Pacific Fusion

Pacific Fusion was founded in 2023 with the mission to power the world with abundant, affordable, clean energy. We are rapidly designing and building a pulser‑driven inertial fusion system to achieve net facility gain (more fusion energy output than stored energy input). In parallel, we are developing the key components required to build affordable fusion systems. Our plans are ambitious. We have raised over $900M so far from incredible investors, resourcing us to deliver on these plans.

We are bringing together the best scientists, engineers, and operators from the fusion community, hard tech industry, and other sectors. We are united by a shared sense of urgency to provide clean power for the world, particularly managing climate change while meeting growing global energy demand. You can read more about us in this letter from our founders.

As a Senior Mechanical Engineer, you will lead the design, development, and integration of complex vacuum seal systems for our pulsed magnetic inertial fusion platform. This role focuses on designing robust seals for high‑vacuum, air, and water interfaces exposed to extreme fusion conditions.

• Design and analyze large, high-performance vacuum seals for water-to-air, air-to-high-vacuum, and water-to-high-vacuum transitions
• Lead experimental design and testing of vacuum seals in collaboration with internal teams, external vendors, and academic partners
• Conduct research into novel sealing techniques; define, execute, and evaluate test campaigns
• Perform FMEA and tolerance stack‑up analyses to ensure seal reliability and system safety
• Design test assemblies for seal validation and risk-reduction
• Review and present technical work across multidisciplinary teams; contribute to system-level integration discussions
• Provide subject‑matter expertise in sealing strategies and guide the integration of vacuum seals into the fusion target area
• Document sealing processes, validation data, and lessons learned
• Mentor and support junior engineers on vacuum system design and integration challenges

• Bachelor's or Master's degree in Mechanical, Aerospace, or a related engineering field, or equivalent experience
• 8+ years of mechanical design experience with a focus on vacuum seals and systems, including rough, high, and ultra-high vacuum environments
• Strong proficiency in CAD, FEM, and engineering analysis tools
• Proven expertise in tolerance analysis, FMEA, seal design, and mechanical integration

$138,100—$263,800 USD

• Industry-competitive salary
• Equity plan
• 6% employer 401k matching
• Generous paid time off (including sick leave, vacation, paid family leave)
• Medical, Dental, and Vision insurance

Pacific Fusion is committed to creating a diverse environment and is proud to be an Equal Opportunity Employer. All qualified applicants will receive consideration for employment without regard to race, color, religion, gender, gender identity or expression, sexual orientation, national origin, genetics, disability, age, or veteran status.

Pacific Fusion is committed to providing reasonable accommodations for qualified individuals with disabilities in our job application procedures and throughout employment. If you need assistance or any accommodation, please let us know.