Staff Product Performance Engineer

Mainspring Energy•Menlo Park, CA

8d•$156,005 - $183,536•Onsite

About The Position

Mainspring Energy is seeking a rigorous, curious, and highly motivated Product Performance Engineer to own the performance of its Linear Generator. Reporting directly to the VP of Test Engineering, this role combines hands-on experimental work with in-depth data analysis to characterize, understand, and improve generator performance, with emphasis on power output, efficiency, and emissions profiles. The position ensures products meet targets defined in the internal Product Requirements Document (PRD) and provides engineering teams with the insight needed to close performance gaps. The role is suited to an engineer or researcher with deep expertise in thermodynamics and power generation who wants to apply that expertise to a first-of-its-kind product in a fast-paced development environment. It is onsite at Mainspring’s Menlo Park headquarters. The listed annual salary range is $156,005–$183,536, adjusted for local market conditions and employee experience. Mainspring also offers pre-IPO RSUs and benefits.

Requirements

PhD in mechanical engineering, aerospace engineering, chemical engineering, physics, or a related field; alternatively, a Master's degree with several years of applicable industry or research experience.
Deep expertise in thermodynamics and power generation, with the ability to apply it to real hardware and experimental data.
Excellent Python data analysis skills, including pandas, NumPy, and SciPy, and experience working with large, noisy experimental datasets.
Hands-on experience designing and executing experiments involving instrumentation and emissions testing.
Strong communication skills and a collaborative mindset, including comfort presenting findings to leadership and working across teams.
Strong organizational skills and ability to manage multiple priorities against deadlines.

Responsibilities

Own measurement and tracking of product performance, including power, efficiency, and emissions, against PRD targets.
Identify gaps between measured performance and PRD targets, and drive cross-functional efforts to close them.
Design and execute experiments on Linear Generator test units, working with technicians and the test team to set up, instrument, and run studies.
Build and maintain Python-based analysis tools and pipelines to process large test datasets, quantify performance, and identify trends and root causes.
Apply first-principles thermodynamic and heat release analysis to explain observed performance.
Communicate results clearly to design engineering teams and make data-driven recommendations that guide design decisions.
Develop and improve test methods, instrumentation, and processes to support performance validation on next-generation products.