Principal Mechanical Engineer

Confirmed live in the last 24 hours

Commonwealth Fusion Systems

Compensation

$150k - $225k/per-year-salary

Milpitas, CA

On-site

Posted April 15, 2026

Job Description

About Commonwealth Fusion Systems:

Commonwealth Fusion Systems is on a mission to deliver the urgent transition to fusion energy.

Combining decades of research, top talent, and new technologies, we’re designing and building commercially viable fusion power plants. And we're working with policymakers and suppliers to build the energy industry of the future.

We’re in the best position to make it happen. Since 2018, we’ve raised nearly $3 billion in capital, making us the largest and leading private fusion company in the world.

Now we’re looking for more thinkers, doers, builders, and makers to join us. People who’ll bring new perspectives, solve tough problems, and thrive as part of a team.

If that’s you and this role fits, we want to hear from you.

Join the power movement as a Principal Mechanical Engineer

We’re looking for a Principal Mechanical Engineer to join our R&D and equipment design team to help build the next generation of thin-film deposition technology. You will be responsible for the end-to-end design, integration, and implementation of advanced thermal vacuum deposition systems and complex R&D machinery.

This role requires you to be a technical expert who can drive innovative architecture while maintaining the procedural discipline necessary for high-performance hardware. If you enjoy solving complex thermal-mechanical problems in vacuum environments and mentoring others in a collaborative, fast-paced setting, this is your opportunity to make an impact.

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