Lead Technician, Assembly Testing

Commonwealth Fusion Systems; Harvard (MA); On-site; USD 85,000 - 110,000; Full time

Benefits offered by this job

Equity

Health, dental, and vision insurance

401(k) with employer matching

Generous parental leave

Flexible vacation days

13 company-wide holidays

Sick days

Job summary

Commonwealth Fusion Systems seeks a Lead Technician, Assembly Testing to direct a small team in executing SASY and related test activities in a high‑hazard environment. You will perform complex mechanical tests, manage documentation, and coordinate with Test Engineering and cross‑functional groups to ensure safe, efficient work.

The role requires 5+ years in mechanical testing, leadership experience, and strong vacuum hardware skills, with a focus on leak detection and pressure testing.

Qualifications

• Hands-on mechanical testing with pneumatic pressure proofing and helium leak detection.
• Experience leading small to mid-sized technician crews.
• Proficiency with high-vacuum hardware and vacuum system plumbing (KF/CF/VCR/NPT).
• Familiarity with setting up vacuum systems and leak detectors.
• Proficiency with Microsoft or Google productivity software.

Responsibilities

• Execute mechanical testing field procedures with emphasis on pneumatic proofing and helium leak detection.
• Supervise test technicians and provide guidance to ensure safe, effective execution.
• Ensure all test documentation is accurate and submitted in a timely manner.
• Collaborate with cross-functional teams and adapt to parallel SPARC assembly activities.
• Drive issues to resolution and uphold safety and compliance standards.

Skills

Mechanical testing

Team leadership

Mass spectrometers

Vacuum systems

Microsoft Office

Google Workspace

Education

HS Diploma

Tools

KF fittings

CF fittings

VCR fittings

NPT fittings

Mass spectrometers

Vacuum pumps

Leak detectors

Job description

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

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.

Join the power movement as a Lead Technician, Assembly Testing

The Mechanical Commissioning Field Lead is responsible for leading a small team (2-3 technicians) in the execution of SASY testing activities under the direction the Manger of Assembly Testing with guidance and support from Test Engineering. These activities may also include assembly activities, as testing will take place in parallel with SPARC assembly. The lead technician will have daily hands‑on responsibilities.

What you’ll do:

• Execute complex testing procedures in the field with a primary focus on mechanical testing to include pneumatic pressure proofing and leak detection using helium leak detector
• Work under the direction of Manager, Assembly Testing, to execute test procedures
• Serve as front line supervisor for test technicians by providing guidance and instruction to technicians to facilitate safe, effective, and efficient execution of work
• Identify issues and potential issues pro‑actively, ensure accurate submission to our work and quality management systems and assist to drive issues to successful conclusions
• Ensure completion of all test documentation in an accurate and timely fashion
• Coach technicians to embody the CFS behaviors and guiding principles in all interactions
• Represent the SASY Test team in collaboration with all CFS cross‑functional teams as required
• Adhere to the highest standards of safety and ensure that activities taking place are being performed in accordance with CFS safety policies and applicable regulatory safety standards

What we’re looking for:

• HS Diploma
• Minimum 5 years of hands‑on mechanical testing experience, with a heavy focus on pneumatic pressure proofing and helium leak detection using mass spectrometers
• Proven experience leading small to medium‑sized crews of technicians performing complex mechanical or testing activities
• Demonstrated experience with high‑vacuum hardware: Must be proficient in plumbing temporary test fixtures and making connections using KF, CF, VCR, compression fittings, and NPT
• Familiarity with setting up and connecting vacuum systems, including turbomolecular pumps and leak detectors
• Mid‑level proficiency in with Microsoft or Google productivity software

Bonus points for:

• Formal training (40+ hours) or active progression toward an ASNT Level II NDT certification in Leak Testing
• Direct experience with specific leak testing methodologies (e.g., tracer probe, hood technique, and helium‑filled object techniques)
• Prior experience working in fusion‑relevant, aerospace, or semiconductor cleanroom environments
• Experience with low or high voltage electrical testing

Must‑have requirements:

• Ability to occasionally lift up to 50 lbs
• Perform activities such as stooping, climbing, typing, standing, or sitting for extended periods of time
• 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
• Willingness to travel or work required nights/weekends/on‑call occasionally

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.

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