Senior Staff Mechanical Engineer

About Mainspring Mainspring Energy manufactures and delivers fuel-flexible, low-emissions local power solutions that rapidly add new capacity and deliver reliable, affordable, and sustainable electric power. The company began commercial shipments of its Mainspring Linear Generators in 2020 and today has hundreds of megawatts in advanced development and field operations for leading Fortune 500 companies, data centers, and utilities. Mainspring also partners with global energy leaders including AEP, NextEra Energy Resources, Schneider Electric, and more. The core values that ground our work, guide our decisions, and connect us together: Pragmatic Optimism Excellence without Ego Proactive Collaboration About the Role 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.