Senior Diagnostics Mechanical Engineer
Devens, MAFull-time$134–205K/yrPosted todayStill listed today
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Job overview
Commonwealth Fusion Systems is assembling the SPARC tokamak and completing the design and installation of diagnostic systems used to control plasma and deliver scientific data. The Senior Diagnostics Mechanical Engineer will support mechanical design and integration as systems move through closeout, analysis, procurement, testing, and installation, working with scientists and engineers to help deliver diagnostic systems for the project.
Skills & qualifications
Skills
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Full 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, suppliers, and many others to build the energy industry of the future.
We’re in the best position to make it happen. Since 2018, we’ve raised $4 billion of capital, making us the largest and leading 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 Senior Diagnostics Mechanical Engineer Commonwealth Fusion Systems is assembling the high-field SPARC tokamak, which aims to be the first magnetic fusion device to achieve net fusion energy, and is predicted to be able to achieve high gain and fusion power up to 140 MW. We are completing the design and have begun the assembly and installation of diagnostic systems that will be used to control the plasma and deliver the scientific data necessary to complete the design of ARC. These include approximately 40 sub-systems covering magnetics, interferometry, neutral pressure, x-ray to visible spectroscopy, camera imaging, bolometry, neutrons, Thomson scattering, electron cyclotron emission, reflectometry, Langmuir probes and structural temperature and strain sensing. A more detailed overview can be found at: https://pubs.aip.org/aip/rsi/article/95/10/103518/3317155. CFS is looking to grow the SPARC team in order to complete the mechanical design and integration of these diagnostic systems as they move through design closeout, analysis, procurement, test, and installation. At present we’re finalizing the design and starting assembly for many of the front-end, in vacuum measurement devices and are looking to add multi-faceted support to help carry those designs across the finish line, take on engineering challenges associated with their build and test, and help design the structural components associated with ex-vessel data transmission to our diagnostic labs. Candidates will work as part of an integrated diagnostic team along with fusion scientists and other engineers to demonstrate net energy from a tokamak for the first time. CFS encourages applications from both senior and early career engineers and those interested in cross-industry career changers to help us build a diverse team to meet our mission goals.
What you'll do:
- Shepherd SPARC diagnostic sub-systems through design closeout, test, and procurement, working with a team of scientists, designers, analysts and engineers
- Integrate technical input from experts on the team to ensure diagnostic designs will survive SPARC’s harsh environments and be usable to achieve SPARC’s scientific mission goals
- Coordinate with manufacturing engineers to align on build and test strategy for complex integrated systems, and support builds in the field to maintain quality and speed
- Contribute to a strong safety culture
What we're looking for:
- Bachelor’s degree in a relevant engineering field (mechanical, aerospace, civil or nuclear)
- 5+ years of relevant experience designing and delivering mechanical systems
- Demonstrated examples of delivering cradle-to-grave mechanical design with nuanced environmental or performance requirements
- Experience designing for manufacturing and assembly, and collaborating with partners to oversee or carry out integrated builds
- Bias toward action, and a balance of engineering intuition and technical rigor that allows for robust, simple designs to be generated with speed
- First principles based approach to engineering and ability to understand concepts and tradeoffs that bridge engineering and physics
- Strong communication skills to gather inputs and distribute information across several partner teams
Bonus points for:
- Experience with Siemens NX, Teamcenter, or Ansys as CAD, PLM, and analysis tools
- Experience with software development, particularly in Python
- Experience designing large equipment requiring lifting/rigging tools to assemble
- Experience with design of systems for exposure to high stress, UHV, high temperature, high magnetic field, and/or radiation environments
Must-have requirements:
- Ability to occasionally lift up to 50 lbs
- Perform activities such as climbing, typing, standing, or sitting for extended periods of time
- Willingness to travel or work required nights/weekends/on-call occasionally
- 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
#LI-Onsite
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.
134000 - 205000 USD a year
Salary range for this full-time position + equity + benefits. The actual salary will depend on level, location, qualifications, and experience. The range displayed on each job posting reflects new hire salaries for the position across all US locations. Benefits include:
- Competitive compensation with equity
- 13 Company-wide Holidays
- Flexible vacation days
- 10 sick days
- Generous parental leave policy
- Health, dental, and vision insurance
- 401(k) with employer matching
- Professional growth opportunities
- Team-building activities
How this job compares
Set against the 7,580 open Mechanical Engineer jobs on Olive Jobs, counted November 5, 2026.
- Pay
- This posting$134–205K/yr
- Massachusetts median$110–165K/yr211 salary ranges
- US median$105–160K/yr4,519 salary ranges
This range's midpoint, $170K, is 22% above the Massachusetts median midpoint ($139K) — in the top quarter of Mechanical Engineer salary ranges in Massachusetts.
- Openings
- Olive Jobs lists 267 open Mechanical Engineer jobs in Massachusetts and 7,580 across the US. 2% of them nationwide are listed as remote or flexible.
- Hiring the most in Massachusetts
- RTX Corporation26 open
- Amazon23 open
- Commonwealth Fusion Systems (this employer)11 open
- Experience
- This posting asks for at least 5 years of experience; Mechanical Engineer postings that state a minimum ask for 5 years at the median (6,305 postings).
- Education
- This posting asks for a bachelor's degree; 5,232 of the 7,580 open Mechanical Engineer jobs (69%) ask for a bachelor's degree or higher.
Counted across the open, public US postings on Olive Jobs on November 5, 2026. Pay medians are the middle values of the low ends and of the high ends of postings that list both ends of a range in the same cadence (a yearly salary or an hourly rate); a range's midpoint is halfway between its ends. Pay and experience figures resting on fewer than 20 postings are left out.
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