Senior Product Performance Engineer

Mainspring Energy•Menlo Park, CA

8d•$129,854 - $152,770•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 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. The central mission is to ensure products meet performance targets defined in the internal Product Requirements Document (PRD) and provide engineering teams with insights to close performance gaps. The role is suited to an engineer or researcher with expertise in thermodynamics and power generation who wants to apply it to a first-of-its-kind product in a fast-paced development environment. The role is onsite at Mainspring's Menlo Park headquarters. The stated salary range is $129,854–$152,770 per year, 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, or a master's degree with several years of applicable industry or research experience.
Deep expertise in thermodynamics or power generation and 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 and collaboration skills, including comfort presenting findings to leadership and working across teams.
Strong organizational skills and the 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 hands-on 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 to design engineering teams and make data-driven recommendations to guide design decisions.
Develop and improve test methods, instrumentation, and processes for performance validation on next-generation products.