---
title: 'Senior Mechanical Engineer at Pacific Fusion'
canonical: 'https://feeny.ai/job/senior-mechanical-engineer-pacific-fusion-san-leandro-ejqecnyqdj85'
type: 'job'
last_seen: '2026-09-10'
---

# Senior Mechanical Engineer at Pacific Fusion

- **Company:** Pacific Fusion
- **Location:** San Leandro, CA
- **Compensation:** $138k–$264k
- **Posted:** 2026-07-07
- **Last confirmed live:** 2026-09-10
- **Apply:** https://job-boards.greenhouse.io/pacificfusion/jobs/4164353009

## Job description

## 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](https://pacificfusion.com/updates/founders-letter).

## Why This Role Matters

Pacific Fusion is seeking an exceptional Senior Mechanical Engineer to help create the path to commercial fusion energy. You will help with the design, analysis, integration, and validation of mechanical systems and components across our advanced fusion energy platform. This role sits at the intersection of precision engineering and first-of-kind technology, demanding both deep technical expertise and the creative problem-solving mindset needed to tackle challenges no one has solved before. You will lead collaborative projects, mentor junior engineers, and play a vital role in driving our overall development effort.

## What You'll Do

- Own assigned mechanical scope end-to-end, providing technical direction to multidisciplinary teams to translate system requirements into robust, deliverable designs
- Provide subject matter expertise in mechanical design and analysis for advanced diagnostic instrumentation, from concept through release
- Develop precision motion and thermal management solutions compatible with high-vacuum and radiation environments
- Define and verify mechanical alignment requirements for optical and detector systems, coordinating with metrology and assembly teams
- Apply optomechanical design principles for mirrors, lenses, and optical mounts to ensure precision alignment and performance of diagnostic systems
- Create and maintain 3D CAD models and 2D fabrication drawings with GD&T for machined, sheet-metal, and additive-manufactured components
- Perform FEA (structural, thermal) to validate designs against shock, vibration, and thermal loads expected in pulsed fusion experiments
- Drive hardware from prototype through delivery, installation, and commissioning, working with vendors and in-house shops in a rapid-turn laboratory setting
- Maintain rigorous revision control and configuration management in PDM/PLM systems: part numbering, BOMs, ECOs, and CAD library maintenance
- Mentor early-career engineers and contribute to the technical development of the broader team
- Perform other duties as assigned

## What You Bring

- Bachelor’s degree in mechanical engineering or related field; advanced degree a plus
- Strong first-principles engineering instincts and problem-solving skills
- 5+ years’ experience in mechanical design for vacuum-compatible instrumentation, ideally with radiation or high-energy diagnostics
- Expert proficiency in a professional 3D CAD platform (Creo, NX, or SolidWorks), GD&T, and producing detailed manufacturing drawings
- Significant experience with FEA tools (ANSYS, COMSOL) for structural and thermal analysis
- Demonstrated ability to navigate competing design constraints simultaneously: vacuum compatibility, radiation tolerance, thermal management, and tight geometric envelopes  internally and between neighboring subsystems
- Proven ability to operate as an effective individual contributor: self-directed and accountable for assigned deliverables end-to-end
- Comfortable driving cross-functional stakeholders — vendors, technicians, and peer engineers — to keep mechanical deliverables on schedule
- Excellent verbal and written communication skills for technical documentation and cross-functional collaboration
- Able to work closely with team members and project manager in fast-paced environment with ambitious deadlines

Bonus Points

- Experience in fusion, plasma physics, accelerator physics, defense, or other high-consequence technical environments.
- Familiarity with vacuum systems, cryogenics, high-voltage hardware, or pulsed power components.
- Exposure to large-scale structural systems, pressure vessels, or custom capital equipment.

Pay Range: $138,100—$263,800 USD

## TOTAL COMPENSATION AND BENEFITS FOR ELIGIBLE EMPLOYEES

- 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

Actual base salary offered will be determined by: experience, skills, and work location. This range is for base salary, our total compensation includes equity and benefits. We welcome you to apply even if your expectations are outside our listed range.

## EQUAL OPPORTUNTITY

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.

## U.S. EXPORT CONTROL COMPLIANCE

This position may require access to information or technology that is subject to U.S. export control laws, such as ITAR or EAR. Under these regulations, we are required to ensure that such access is provided only to individuals who are classified as 'U.S. Persons.'This status includes U.S. citizens, U.S. nationals, lawful permanent residents (green card holders), and asylees and refugees with such status granted, not pending.

## RECRUITING AGENCIES

Pacific Fusion does not accept unsolicited resumes from recruiters or employment agencies without a fully executed recruitment agreement in place. In the absence of such agreement, Pacific Fusion reserves the right to pursue and hire any candidates without an obligation to pay fees. Agencies are requested not to contact Pacific Fusion hiring managers or employees regarding recruiting services.

## About Pacific Fusion

## Company Overview
- **One-liner**: Pacific Fusion is developing a pulsed magnetic inertial fusion system designed to deliver affordable, clean, commercial fusion energy by the early 2030s.
- **Entity Type**: Private (Series A)
- **Headquarters**: Fremont, California, United States
- **Founded**: 2023
- **Founders**: Eric Lander (CEO), Keith LeChien (CTO), Carrie von Muench (COO), Will Regan, Leland Ellison

## Core Business
- **Primary Industry**: Fusion Energy / Renewable Energy Power Generation
- **Target Customers**: Utility companies, large-scale industrial power consumers, and governments seeking clean, baseload energy generation.
- **Mission Statement**: To power a prosperous planet by delivering affordable, reliable fusion power to meet growing global energy demand and address the climate crisis [pacificfusion.com](https://pacificfusion.com/).

## Products & Services
- **Pulsed Magnetic Inertial Fusion System**: A modular fusion power plant design that uses a fast, powerful electrical pulser to rapidly compress small fuel containers (centimeter-scale) of deuterium-tritium fuel. The system is designed to achieve "net facility gain" — producing more fusion energy output than the total stored energy input. The approach is highly modular, enabling affordable manufacturing and rapid iteration using common materials [pacificfusion.com](https://pacificfusion.com/).

## Market Standing
- **Valuation/Market Cap**: Not publicly disclosed.
- **Key Metric (Total Funding)**: Over **$900 million** raised in Series A funding (announced October 2024) [linkedin.com](https://www.linkedin.com/company/pacificfusion), [wikipedia.org](https://en.wikipedia.org/wiki/Pacific_Fusion).
- **Notable Investors/Partners**: Led by **General Catalyst**, with participation from **Breakthrough Energy Ventures**, **Ken Griffin** (Citadel founder), **Patrick Collison** (Stripe co-founder), **John Doerr** (venture capitalist), **Mustafa Suleyman** (Microsoft AI), and **Eric Schmidt** (former Google CEO) who joined the board [wikipedia.org](https://en.wikipedia.org/wiki/Pacific_Fusion).
- **Growth Signals**:
    - Headcount has grown **118.8% YoY** to approximately 151 employees [linkedin.com](https://www.linkedin.com/company/pacificfusion).
    - In September 2025, selected Mesa del Sol, Albuquerque, New Mexico, for a **$1 billion research and manufacturing facility**, expected to create 200 permanent jobs and ~1,000 construction jobs [wikipedia.org](https://en.wikipedia.org/wiki/Pacific_Fusion).
    - In December 2025, opened its first build center in Los Lunas, New Mexico [wikipedia.org](https://en.wikipedia.org/wiki/Pacific_Fusion).
    - In June 2026, achieved a key technical milestone: a scaled module prototype delivered **over 440 GW of peak output power** and **~1.1 MV peak voltage** in ultra-fast pulses, demonstrating the performance required for fusion conditions [wikipedia.org](https://en.wikipedia.org/wiki/Pacific_Fusion).

## Competitive Advantages
- **Proven Science, Practical Engineering**: The company is building on decades of government-funded research (including breakthroughs at Sandia and US National Labs in 2022) and using an advanced pulsed power driver (the Impedance-Matched Marx Generator, co-invented by CTO Keith LeChien), which is designed to be simpler and more manufacturable than other fusion approaches [pacificfusion.com](https://pacificfusion.com/), [wikipedia.org](https://en.wikipedia.org/wiki/Pacific_Fusion).
- **Modular and Affordable Design**: The system is made of three highly modular parts (a fast electric pulser, a small fusion chamber, and tiny fuel containers), enabling cheap, rapid iteration and supply chain simplicity [pacificfusion.com](https://pacificfusion.com/).
- **Clear Path to Commercialization**: The company has a defined roadmap with milestone-based funding, a specific goal of achieving net facility gain by 2030, and is already investing heavily in large-scale manufacturing facilities [pacificfusion.com](https://pacificfusion.com/), [wikipedia.org](https://en.wikipedia.org/wiki/Pacific_Fusion).

## Strategic Focus
- **Technical Milestone Execution**: Rapidly building and testing scaled prototypes of their pulser system to demonstrate fusion conditions.
- **Manufacturing Scale-Up**: Building out the $1 billion facility in New Mexico to house the Demonstration System and prepare for commercial production.
- **Talent Acquisition**: Aggressively hiring top-tier scientists, engineers, and operators from the fusion community, national labs, and hard-tech industry (e.g., Lawrence Livermore, Los Alamos, Tesla, SpaceX) [linkedin.com](https://www.linkedin.com/company/pacificfusion).
- **Workforce Development**: Partnering with local universities in New Mexico to create training programs for its future workforce [wikipedia.org](https://en.wikipedia.org/wiki/Pacific_Fusion).

## Why Work Here
- **Mission-Driven Impact**: Employees are united by a "shared sense of urgency" to solve the climate crisis and provide clean, abundant power for the world [pacificfusion.com](https://pacificfusion.com/careers).
- **Award-Winning Culture**: 100% of employees say Pacific Fusion is a Great Place to Work (vs. 57% at a typical US company), earning the company the #60 spot on Fortune's Best Workplaces in the Bay Area™ 2025 list [greatplacetowork.com](https://www.greatplacetowork.com/certified-company/7085506).
- **Core Values**: The company operates on four key values: *Support each other, Pursue the truth, Encourage creative approaches, Commit to impact* [pacificfusion.com](https://pacificfusion.com/careers).
- **Work Environment**: A builder's mentality with a mix of scientists, engineers, and operators. Roles are on-site in Fremont, CA; San Leandro, CA; Albuquerque, NM; and Los Lunas, NM. The culture emphasizes rapid iteration, open communication, and practical engineering.
- **Strong Financial Backing**: With over $900M in funding from top-tier investors, the company is well-resourced to pursue its ambitious timeline.

## Sources
1. [pacificfusion.com](https://pacificfusion.com/)
2. [pacificfusion.com/careers](https://pacificfusion.com/careers)
3. [linkedin.com/company/pacificfusion](https://www.linkedin.com/company/pacificfusion)
4. [wikipedia.org/wiki/Pacific_Fusion](https://en.wikipedia.org/wiki/Pacific_Fusion)
5. [greatplacetowork.com](https://www.greatplacetowork.com/certified-company/7085506)

## Other roles at Pacific Fusion

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- [Summer 2027 Internship- Software Engineering](https://feeny.ai/job/summer-2027-internship-software-engineering-pacific-fusion-san-leandro-ca-sjnerfajh3nk) — San Leandro Ca/fremont CA OR Los Lunas, NM
- [Summer 2027 Internship - Electrical Engineering](https://feeny.ai/job/summer-2027-internship-electrical-engineering-pacific-fusion-san-leandro-ca-e8vy78c5z1v2) — San Leandro Ca/ Fremont CA OR Los Lunas, NM
- [Summer 2027 Internship- Mechanical Engineering](https://feeny.ai/job/summer-2027-internship-mechanical-engineering-pacific-fusion-san-leandro-ca-82c4h67r4wj3) — San Leandro Ca/fremont CA OR Los Lunas, NM
- [Manufacturing Systems  Analyst](https://feeny.ai/job/manufacturing-systems-analyst-pacific-fusion-san-leandro-qk55y71ff0e3) — San Leandro, CA
- [Summer 2027 Internship-Manufacturing Engineering](https://feeny.ai/job/summer-2027-internship-manufacturing-engineering-pacific-fusion-san-leandro-09kxn4d8q0pf) — San Leandro, CA / Fremont, CA / Los Lunas, NM
- [Senior Mechanical Engineer - Vacuum Systems](https://feeny.ai/job/senior-mechanical-engineer-vacuum-systems-pacific-fusion-fremont-keva8g47wjzp) — Fremont, CA
- [Senior Manufacturing Engineer - NPI](https://feeny.ai/job/senior-manufacturing-engineer-npi-pacific-fusion-fremont-pmh1tcd60e6v) — Fremont, CA
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