Commonwealth Fusion Systems

Field Mechanical Engineer - Assembly

Join Commonwealth Fusion Systems in Devens, Massachusetts as a Field Mechanical Engineer. Lead assembly of fusion power components, solve complex mechanical challenges, and collaborate with design teams. Enjoy working in a cutting-edge fusion energy environment with a strong mission and competitive salary.
Commonwealth Fusion Systems
Commonwealth Fusion Systems
Devens, Massachusetts, United States On-site Full time USD 90k–145k yearly UTC-05:00

Commonwealth Fusion Systems

Company Overview

Commonwealth Fusion Systems (CFS)

Cambridge, MA, United States

2018

Approximately 430 employees (source: zoominfo.com). Revenue figures vary, with reports indicating $211.3 million or $31.7 million, though as a pre-revenue fusion developer focused on R&D, these may reflect funding or operations rather than sales.

What They Do

Commonwealth Fusion Systems (CFS) is a pioneering private fusion energy company that specializes in tokamak-based magnetic confinement fusion. Founded as a spinout from MIT's Plasma Science and Fusion Center, CFS focuses on utilizing high-temperature superconducting magnets to achieve commercial net energy production (source: cfs.energy). The company has made significant strides in its technology, particularly with the development of compact fusion machines that leverage decades of tokamak science. Their flagship projects, SPARC and ARC, aim to demonstrate net energy gain and commercial viability in the coming years (source: cfs.energy).

Projects & Track Record

CFS is currently engaged in several groundbreaking projects, most notably the construction of SPARC, which is set to be the world's first net-energy fusion machine. Located at their Fusion Energy Campus in Devens, Massachusetts, SPARC aims to demonstrate net energy gain by the late 2020s (source: cfs.energy). Additionally, CFS is planning the ARC project, a 400 MW-class grid-scale tokamak power plant designed for commercial deployment in the early 2030s. These projects are underpinned by significant technological advancements, including the successful testing of the central solenoid magnet module (CSMC) in November 2024, which confirmed the manufacturability of critical components for SPARC (source: zoominfo.com).

Recent Developments

In the past two years, CFS has made remarkable progress, including the opening of its Devens Fusion Energy Campus on February 10, 2023, which was attended by notable figures such as U.S. Secretary of Energy Jennifer Granholm (source: cfs.energy). The company has also secured substantial funding, raising $863 million in August 2024, building on a previous $1.8 billion round in May 2023, bringing total funding to over $2 billion (source: wbjournal.com). Furthermore, CFS announced its first commercial power plant site in Chesterfield County, Virginia, which will be independently financed and operated, with plans for grid connection in the early 2030s (source: zoominfo.com).

Working There

CFS offers a range of roles across various disciplines, including fusion science, engineering, manufacturing, and materials science. The majority of their workforce is based at the Devens campus, which has grown to over 430 employees (source: cfs.energy). The company culture emphasizes rapid execution and transparency, attracting top talent from the fusion and manufacturing sectors. Key executives include Co-Founder and CEO Bob Mumgaard, along with other leaders in operations and science, indicating a strong demand for expertise in tough tech and physics (source: nasdaqprivatemarket.com). While specific benefits are not detailed, the scale-up and investor backing suggest competitive packages for high-caliber roles in a mission-driven environment (source: cfs.energy). Job seekers are encouraged to monitor their careers page for openings related to SPARC and ARC advancements.


Last updated on Feb 23, 2026 | Report an issue

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.

What you'll do

  • Co-own and be the expert in the assembly sequence of your workstation (initially this role is scoped to the assembly of the Toroidal Field Coil (TF) semicircle sub-assemblies), with the responsibility to determine and enact acceptable solutions and changes to the sequence that both allow successful completion of the work-station but also fit with the entire SPARC assembly sequence
  • Be responsible for new first-encounter work scope definition including the installation of various manifolds and magnet sub-assemblies
  • Determine and execute solutions for identified assembly issues that arise, such as fit, method, or component handling problems. Work with the Tokamak System design teams to determine how a part or process step could be modified to work while also meeting functional requirements
  • Proactively procure or build all tools, fixtures, or manipulation equipment required for the upcoming ports of the process in your workstation
  • Serve as the owner for a process by testing, implementing, and handing off to production technicians for repeated use for any given operation or tool(s)
  • Provide design feedback to SPARC sub-system designs with a focus on manufacturing and assembly. Participate in both formal and informal design reviews to ensure what is delivered can be assembled
  • Assist in the disposition and resolution of non-conformance issues on parts or the process, then working to incorporate and release red-line changes into an updated assembly sequence.
  • Support hands on operations during Tokamak Assembly serving a variety of roles in the process
  • Work with teammates in a collaborative fashion to receive feedback early and often to ensure all requirements are met. Many SPARC projects involve high loads, vacuum requirements, and complex manipulation requiring the involvement and review of adjacent sub system experts

What we're looking for

  • Civil, Mechanical, or Aerospace Engineering B.S. with 5 years' experience
  • 3+ years' of Mechanical Engineering Experience demonstrating project ownership
  • 2+ years' experience overseeing an in-progress construction, manufacturing, or assembly/integration process
  • 2+ years' of experience with CAD software

Bonus points for

  • 6+ years of Mechanical Engineering Experience demonstrating project ownership
  • Experience with Siemens NX
  • Lifting operations experience
  • Knowledge of welding
  • Knowledge of piping and tubing construction and joining
  • Experience with highly complex or delicate assemblies
  • Experience with assembly or integration in tightly packaged spaces
  • Experience with fast-paced and dynamic construction, manufacturing, or assembly/integration builds
  • Experience with composite preparation, layup, and curing.
  • Experience with cable, tubing, bracing alignment and securing
  • Experience with fiber inspection and splicing work and equipment
  • Heavy component manipulation of large structures

Must-have Requirements

  • Ability to occasionally lift up to 50 lbs
  • Perform activities such as typing, standing, stooping, climbing or sitting for extended periods of time
  • Required onsite 5 days/week when assembly operations with relevant tools are underway, with possible alternating first or second shift assignment
  • Work in a facility that contains industrial hazards including heat, cold, noise, fumes, strong magnets, lead (Pb), high voltage, high current, pressure systems, and cryogenics

$90,000 - $145,000 a year

At CFS, we excel in fast-paced environments, driven by our values of integrity, execution, impact, and self-critique. As we grow, we're eager to bring on mission-driven folks who offer diverse perspectives and fresh ways to tackle challenges.

We value diversity deeply and are proud to be an equal opportunity employer by choice. We consider all qualified applicants equally, regardless of race, color, national origin, ancestry, citizenship status, protected veteran status, religion, physical or mental disability, marital status, sex, sexual orientation, gender identity or expression, age, or any other basis protected by law.

This role requires compliance with U.S. laws concerning the export of controlled or protected technologies or information (collectively, "Export Control Laws"). Any offer of employment will be contingent on the need for compliance with such Export Control Laws.

Apply now

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About the role

June 26, 2026

June 26, 2026

Full time

On-site

Company

USD 90k–145k yearly

Hydrogen

Commonwealth Fusion Systems

cfs.energy

  •  Devens, Massachusetts, United States

5+ years of experience in Mechanical Engineering

UTC-05:00