Posted on:March 13, 2026

Senior Mechanical Design Engineer at Inertia

Inertia is hiring a Senior Mechanical Design Engineer in Livermore, CA, US. On-site. Pay: USD 180k-240k/yr.

About Inertia

Inertia is a commercial fusion energy company. It is developing a laser-based fusion power system, including high-power modular lasers, mass-produced fusion fuel targets, and gigawatt-scale power plants, based on the fusion ignition approach demonstrated at the U.S. National Ignition Facility. The company aims to commercialize fusion energy within the next decade.

Senior Mechanical Design Engineer job description

Overview

We are seeking a Senior Mechanical Design Engineer within the laser division, to play a key role in developing the next generation of ultra-high energy pulsed laser systems for fusion energy. Typical design projects would include the design and development of solid-state laser hardware and systems, large-aperture opto-mechanical mounts and positioning systems, support structures, vacuum chambers and systems, thermal management systems, and test stands and diagnostics.

What You'll Get to Do

  • Gather and develop requirements for systems with stakeholders across all disciplines.

  • Conceptualize system architectures and concepts based on high-level requirements.

  • Lead small teams in the design of precision mechanical and opto-mechanical equipment and systems for IFE facilities.

  • Design mechanical, opto-mechanical, and electro-mechanical equipment and systems.

  • Validate design work with appropriate analysis (static and modal FEA, hand calculations, etc.).

  • Present at design reviews to science and management stakeholders.

  • Work closely with other disciplines in the design and coordination of activities.

  • Integrate precision opto-mechanical, fluidic, and electrical hardware, designed both in-house and by subcontractors, into large-scale CAD assemblies that include facility BIM data.

  • Perform detailed component materials and finish specifications, manage technical data transfer to suppliers, inspect and qualify hardware following procurement.

  • Assemble prototype hardware; develop and execute test plans for subsystem performance validation.

  • Utilize large-scale CAD assemblies to provide assembly documentation and installation schedules for opto-mechanical and electrical systems.

  • Guide and mentor other engineers.

What You Bring to Inertia

  • 10+ years of experience as a mechanical design engineer.

  • Proven history of delivering novel and innovative solutions to challenging problems.

  • Proficiency with 3D CAD packages; SolidWorks (preferred), CREO, Autodesk Inventor, etc.

  • Thorough knowledge of drafting, tolerance analysis, and Geometric Dimensioning and Tolerancing (GD&T).

  • Demonstrated experience with FEA - Structural, Modal, Random Vibration with empirical validation.

  • Experience with CFD analysis with empirical validation.

  • Practical knowledge of manufacturing processes (machining, sheet metal, welding) and design for manufacturability (DFM).

  • Experience specifying components for precision design: linear stages, rotary motors, encoders, optical sensors, pneumatic components, vacuum components, etc.

  • Full design lifecycle experience including design, procurement, assembly, and test of mechanical systems.

  • Experience with cleanroom procedures, high-voltage, and high-vacuum environments.

  • Experience designing laser systems or optical instruments.

  • Due to the nature of this position, applicants must be U.S. citizens or permanent residents.

Salary & Benefits:

  • The base salary range for this role is $180,000 - $240,000 per year; The pay range provided is an estimated base range for this role. Exact compensation may vary based on skills, experience, and education.

  • We offer market-competitive compensation and an excellent benefits program, including Medical, Dental, and Vision plans, company-paid holidays, matching 401k, and more!

About Inertia:

Inertia is taking the most direct, scientifically-proven path to commercializing fusion, leveraging the only successful achievement of fusion ignition, using a process that was pioneered at the U.S. Department of Energy’s (DOE) Lawrence Livermore National Laboratory (LLNL). With groundbreaking innovation, transformative technology, and multi-year investment, Inertia is committed to commercializing fusion energy in the next decade.

This position requires access to technology, software and other information that is subject to governmental access control restrictions, due to export controls, security classification and/or designation as Controlled Unclassified Information. Employment in this position is conditioned on the candidate’s eligibility for, obtaining and maintaining appropriate government authorization to access technology or information, to the extent required, including without limitation a security clearance, export license, or other documentation required to establish authorization to receive access to such items technology or information.

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Applications go straight to Inertia. We never sit between you and the employer.

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