Senior Staff Mechanical Engineer

About the role

You will define and own the system-level architecture for key mechanical subsystems across multiple Linear Generator programs, ensuring alignment with reliability, cost, and manufacturability goals. You will act as a cross-functional integrator, translating ambiguous business and performance requirements into coherent technical strategies that span design, analysis, validation, and operations. You will leverage deep expertise in mechanical dynamics, thermodynamics, and materials behavior to anticipate failure modes and guide tradeoffs before they escalate into program risk. You will establish and enforce technical standards, validation frameworks, and design baselines that allow multiple teams to execute efficiently and with shared context. You will mentor other engineers by elevating decision quality, improving documentation, and creating reusable technical assets that reduce duplicated effort and recurring defects. You will partner closely with leaders in product, operations, and supply chain to align technical roadmaps with commercial milestones and field performance expectations. You will own the hard problems that sit between projects, resolving cross-team dependencies and surfacing integration risks that individual teams cannot see on their own. You will represent Mainspring Energy in external technical discussions where appropriate, ensuring that our hardware strategy reflects best practices and evolving stakeholder needs.

Key facts

What you'll do

Define system-level mechanical architectures and coordinate interfaces across subsystems to maintain coherence as programs scale.

Lead root cause investigations for complex field and test failures, driving corrective actions that prevent recurrence across the fleet.

Develop and maintain validation and test strategies that provide confidence in performance, durability, and safety across diverse operating conditions.

Translate customer and regulatory requirements into technical specifications that balance performance, cost, and manufacturability.

Own critical design reviews and gate decisions, ensuring that assumptions, analyses, and test data are consistent and sufficiently rigorous.

Create and evolve design standards, best practices, and tooling that enable efficient reuse and reduce variability between engineering teams.

Partner with operations and service teams to diagnose in-field issues and convert insights into durable design improvements.

Collaborate with supply chain and manufacturing to simplify designs, improve yields, and reduce production complexity without sacrificing reliability.

Model and analyze dynamic and thermal behaviors of mechanical systems to guide component selection and integration decisions.

Establish traceability between requirements, design decisions, and verification results to make program risks visible and manageable.

Drive the development of diagnostic and monitoring capabilities that support both customers and field engineers in deploying and maintaining systems.

Champion data-driven decision-making, ensuring that key performance trends inform priorities and tradeoffs across the development roadmap.

Identify opportunities to standardize components and processes across programs, enabling economies of scale and faster onboarding of new teams.

Support hiring and development of mechanical engineers by defining role expectations, evaluating technical work, and mentoring through complex problems.

Engage with external partners, utilities, and customer teams to communicate technical direction and align on implementation plans.

Requirements

You have a Bachelor's degree in Mechanical Engineering or a closely related field, and your most recent role involved significant mechanical design responsibility.

You have at least 10 years of progressive experience in mechanical engineering roles, with a demonstrated record of owning complex system-level problems.

You have at least 8 years of experience applying first-principles modeling and analysis methods to mechanical systems, including dynamics, thermal, and structural problems.

You have at least 8 years of experience leading the development, validation, and execution of hardware test plans for critical mechanical systems.

You have at least 6 years of experience guiding design decisions and tradeoffs in a program or product development environment.

You have at least 6 years of experience interfacing with manufacturing, quality, and operations teams to ensure designs are producible, serviceable, and reliable at scale.

You are proficient in core mechanical analysis tools and methods, including multi-body dynamics, finite element analysis, and design of experiments.

You are comfortable working with incomplete information and formulating clear problem statements, hypotheses, and test plans under uncertainty.

You can communicate effectively with both technical and non-technical stakeholders, translating deep engineering details into actionable recommendations.

You are comfortable operating in a fast-paced, ambiguous environment where priorities evolve based on customer needs and field feedback.

Nice to have

Experience with fuel-flexible power systems, internal combustion, or related thermal machines is preferred.

Experience in data center, utility, or mission-critical power markets is preferred.

Experience with digital twins, sensor-based diagnostics, or condition-based monitoring is preferred.

Experience with ISO or other functional safety and quality standards in regulated environments is preferred.

Experience leading distributed or cross-site engineering teams is preferred.

Practical notes

This role is based in Menlo Park, California, and requires consistent in-person presence during standard business hours.

Travel may be required up to 25 percent of the time for customer engagements, design reviews, or field investigations.

Employment eligibility to work in the United States is required, and no sponsorship is available for this role at this time.

The position is salaried and classified as full-time, with performance expectations aligned to Mainspring's career levels.