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 Mechanical Engineer to own defined-scope mechanical engineering tasks, workstreams, or moderate-complexity projects for our Linear Generator platform. In this role, you will design mechanical hardware, support analysis and testing, drive assigned work through validation and release, and work cross-functionally with engineering, manufacturing, quality, supply chain, test, and service teams. This role is intended for engineers who have developed practical mechanical engineering experience through multiple design, analysis, test, release, or implementation cycles. A strong candidate should be able to independently own defined-scope engineering work, apply sound mechanical fundamentals, identify common risks, communicate clearly, and follow through on deliverables with support available for ambiguity, complex tradeoffs, or higher-risk decisions. Candidates who are still primarily learning engineering fundamentals, company processes, and task-level execution may be better aligned to an Associate Mechanical Engineer role, while candidates who have already demonstrated independent ownership of significant projects, subsystems, or technical workstreams may be better aligned to a Senior Mechanical Engineer role.