Senior Staff Mechanical Engineer

Mainspring Energy•Menlo Park, CA

4d•Onsite

About The Position

Mainspring is seeking a Senior Staff Mechanical Engineer to shape technical direction across multiple teams, systems, or major program areas within our Linear Generator platform. In this role, you will guide system-level design decisions, resolve complex cross-functional tradeoffs, identify risks that may not be visible within individual projects, and create technical leverage through architecture, standards, validation strategy, and high-quality decision-making. This role is intended for engineers who have already demonstrated advanced technical ownership within a major subsystem, team, or technical area and are now ready to influence outcomes across a broader part of the organization. A strong candidate should be able to operate with high autonomy, frame ambiguous system-level problems, align stakeholders, improve technical decision quality across projects, and help teams avoid rework caused by weak assumptions, incomplete validation, or missed integration risks. Candidates who primarily provide technical leadership within one team, subsystem, or technical area may be better aligned to a Staff Mechanical Engineer role, while candidates who serve as a company-level technical authority in a critical domain may be better aligned to a Principal Mechanical Engineer role.

Requirements

BS, MS, or PhD in Mechanical Engineering or a similar engineering field, with demonstrated success providing technical leadership across complex mechanical systems, subsystems, or major program areas.
Repeated experience developing, validating, releasing, and improving complex hardware across multiple design cycles, project types, failure modes, and implementation environments.
Strong system-level mechanical judgment, including the ability to balance performance, reliability, cost, manufacturability, serviceability, scalability, safety, schedule, integration, and business priorities.
Demonstrated ability to resolve ambiguous, cross-functional technical problems where ownership, requirements, evidence, or tradeoffs are not initially clear.
Proven ability to use analysis, testing, data, field learning, production learning, and engineering judgment to make or guide high-consequence technical decisions.
Strong communication and influence skills, including the ability to align stakeholders across teams and levels of the organization around technical strategy, risks, tradeoffs, and recommended paths forward.

Nice To Haves

Experience serving as the technical lead or subject matter expert for a broad system, product area, platform, or discipline.
Experience developing hardware for energy systems, engines, generators, compressors, pumps, thermal systems, fluid systems, structures, high-cycle fatigue environments, precision alignment systems, electromechanical systems, or industrial equipment.
Experience creating design standards, architecture principles, validation methods, risk frameworks, review practices, troubleshooting methods, or other reusable approaches that improve engineering execution across teams.
Experience with reliability strategy, accelerated life testing, failure analysis, structured root cause analysis, design of experiments, risk-based validation planning, or system-level trade studies.
Experience influencing major technical decisions across engineering, manufacturing, quality, supply chain, suppliers, service, product, or leadership stakeholders.
Experience helping teams sequence work, reduce uncertainty, avoid rework, and focus on the highest-leverage technical problems.

Responsibilities

Lead technical direction for a broad system, platform area, discipline, or group of related mechanical projects with high ambiguity, system-level tradeoffs, and major program impact.
Guide architecture, system, subsystem, or platform-level design decisions that affect multiple projects or teams, balancing technical performance, reliability, cost, manufacturability, serviceability, scalability, and business priorities.
Frame complex cross-functional problems at the right level, identify critical tradeoffs, and drive alignment on practical technical paths forward.
Establish analysis, validation, test, and data strategies for major technical decisions where the available evidence may be incomplete, imperfect, or spread across models, experiments, field data, and production learning.
Identify system-level risks, recurring failure modes, integration gaps, and organizational blind spots that may not be visible within individual projects.
Create technical leverage across teams through design reviews, risk reviews, architecture discussions, technical strategy, standards, methods, troubleshooting, and guidance on high-consequence decisions.