About the Company

General Matter enriches uranium.

We are designing, building, and operating the world’s lowest-cost enrichment services, here in the US.  

In the process, we are restoring America’s ability to produce nuclear fuel to power AI, advanced manufacturing and critical industries our country relies on to remain competitive. 

Fuel drives the cost of advanced reactor electricity production, and enrichment drives the cost of the fuel that advanced reactors consume.  Reliable, low-cost enrichment is the catalyst for the nuclear Renaissance now under way.

Our mission is to make nuclear not only the cleanest and safest source of baseload power, but also the most affordable.  We believe abundant nuclear energy will lead to a post-scarcity society. 

We were incubated inside Founders Fund, like Anduril and Palantir before us, and are backed by over a dozen of the world's top venture capital firms.  

Our lean, world-class team of engineers and operators is applying a first-principles approach to solving the problem of nuclear fuel production.  

We are a mission-driven company with a culture of urgency, accountability, and transparency. 

Help us build a high-energy society by making the cleanest, safest form of baseload energy the most affordable.

About This Role

As a General Matter Mechanical Test Engineer, you will build the test infrastructure and execute the test campaigns that qualify the mechanical hardware behind our next-generation enrichment technology — including precision optical mounts, alignment stages, beam delivery paths, and structures that must survive demanding thermal, vibration, shock, and material-compatibility conditions unique to uranium processing. You'll work hands-on with prototype and production hardware, design fixtures and test setups from scratch, and partner closely with the mechanical, optical, materials, and manufacturing engineers who design the hardware you're qualifying. If you seek high impact and are excited by fast-paced, intense, Skunkworks-style projects at the frontier of enrichment technology, we encourage you to apply to join our team.

Responsibilities

• Design, build, and maintain test fixtures, rigs, and setups for mechanical, thermal, vibration, shock, and durability testing of enrichment hardware, including precision optical and beam delivery assemblies.
• Develop and execute test plans that verify mechanical performance, alignment stability, and beam pointing/positioning accuracy under representative environmental and process conditions.
• Perform coupon- and component-level materials testing (e.g., fatigue, corrosion, wear, thermal cycling) to support material selection and qualification decisions.
• Instrument test articles and collect, reduce, and analyze test data to assess pass/fail criteria and identify design margins.
• Perform root-cause analysis on test failures and partner with design engineers to develop and verify corrective actions.
• Own test documentation, including test plans, procedures, reports, and qualification packages, ensuring traceability for engineering and regulatory purposes.
• Continuously improve test methods, tooling, and lab infrastructure to increase test throughput and fidelity as hardware iterates rapidly.
• Work closely with mechanical, optical, materials, manufacturing, and nuclear engineers to translate test results into design and process improvements.

Basic Qualifications

• Evidence of exceptional ability (prior projects, portfolio of work, completed products, etc).
• Bachelor's degree in Mechanical Engineering or a related field.
• 3+ years of experience in mechanical test engineering, environmental test, or hardware qualification via project team, research, internship, and/or professional experience.
• Hands-on experience designing and building test fixtures and instrumented test setups.
• Working knowledge of environmental test methods (vibration, shock, thermal cycling, thermal vacuum, durability/fatigue).
• Comfortable working directly with hardware in a lab environment, including troubleshooting instrumentation and data acquisition systems.

Preferred Skills and Experience

• Background or working knowledge in materials science or metallurgy, particularly failure analysis, fatigue/corrosion testing, or performance of metals and alloys under extreme thermal, mechanical, or corrosive conditions.
• Experience testing precision optical or photonic-based hardware — for example alignment stage repeatability, beam pointing/stability verification, or thermal management validation for high-energy optical components.
• Experience with data acquisition systems, sensors (accelerometers, strain gauges, thermocouples, sensors), and test automation.
• Strong understanding of engineering fundamentals and statistical methods for interpreting test data.
• Experience in a fast-paced engineering environment or a highly technical role requiring a resourceful, entrepreneurial approach to complete tasks within tight timeframes or budget constraints.

Additional Requirements

• Ability to work extended hours and weekends as necessary.

Equal Opportunity Employer

General Matter is an Equal Opportunity Employer; employment with General Matter is governed on the basis of merit, competence and qualifications and will not be influenced in any manner by race, color, religion, gender, national origin/ethnicity, veteran status, disability status, age, sexual orientation, gender identity, marital status, mental or physical disability or any other legally protected status.

Compensation and Benefits

The base salary range for this role is $110,000–$180,000 annually. 

Compensation bands are determined by role, level, location, and alignment with market data. Individual level and base pay is determined on a case-by-case basis and may vary based on job-related skills, education, experience, technical capabilities and internal equity. Please note that the stated salary range is an estimate and may be adjusted based on market conditions, business needs, or other factors. In addition to base salary, for full-time hires, you may also be eligible for long-term incentives, in the form of stock options, and access to medical, vision & dental coverage as well as access to a 401(k) retirement plan.