Senior Mechanical Engineer

Senior Mechanical EngineerEndurance is building the world's first modular subsea geothermal power plants, converting vast thermal resources under the ocean into gigawatts of baseload power. Backed by Founders Fund, Felicis, First Round Capital, and Point72 Ventures, our founding team includes veterans from SpaceX, Helion, Blue Origin, and Apple. We have completed multiple deep-ocean deployments to subsea volcanoes and are launching a long-term demonstration project this fall. By leveraging modular design, manufacturing scale, efficient drilling, and latent cooling on the seafloor, we are pioneering a new category of energy that outperforms traditional sources on environmental impact, deployment speed, and cost.As a Senior Mechanical Engineer, you will own critical mechanical systems within our seafloor power plants. These systems must survive high pressure, corrosion, thermal cycling, mechanical loads, and long deployment durations in saltwater environments. You will design and deliver pressure-tolerant structures, thermal systems, fluid interfaces, deployment hardware, and mechanical subsystems that operate reliably on the ocean floor. This role blends rigorous analysis with hands-on hardware development.You will take ambiguous, high-risk mechanical systems including pressure vessels, structural frames, thermal interfaces, fluid systems, and deployment hardware and drive them from first principles to offshore deployment. This role requires deep mechanical intuition and extreme ownership. You will architect systems, design parts, release drawings, build prototypes, run tests, break hardware, and iterate until the system works reliably. If a machine fails on the seafloor, you will feel responsible for fixing it permanently.We are looking for someone who has personally built hardware, debugged mechanical failures in the lab or field, and understands the difference between a clean CAD model and a system operating in a harsh environment.Key ResponsibilitiesArchitect and design critical mechanical systems from concept through offshore deploymentPerform first-principles analysis of loads, thermal behavior, sealing strategies, and failure modesDesign pressure-tolerant hardware, structural systems, and thermal interfaces for subsea environmentsDevelop robust sealing and corrosion mitigation strategies for long-duration saltwater exposureDesign assemblies including pressure housings, structural frames, fluid systems, and deployment mechanismsCreate detailed 3D CAD models, drawings, and tolerance stacks for complex hardwareBuild and test prototypes to validate mechanical performance and uncover failure modesDesign and execute qualification tests including pressure testing, fatigue testing, thermal cycling, and corrosion exposureInvestigate hardware failures and implement permanent design improvementsWork directly with fabricators and suppliers to build hardware quickly and correctlyCollaborate with electrical, drilling, and subsea systems teams to ensure clean system integrationParticipate in sea trials and field deployments to validate hardware performanceQualifications6+ years designing and delivering complex mechanical systems in demanding environmentsDemonstrated ownership of hardware from early concept through testing and deploymentStrong first-principles understanding of mechanics, materials, thermal systems, and failure modesDeep proficiency in 3D CAD and mechanical design of complex assembliesExperience designing hardware for harsh environments (subsea, aerospace, automotive, energy, robotics, etc.)Proven ability to debug mechanical failures through testing and root-cause analysisStrong intuition for structural load paths, sealing strategies, corrosion mitigation, and thermal managementComfort working hands-on with hardware in a lab or shop environmentAbility to move quickly, close loops, and make good engineering decisions under uncertaintyHigh ownership mentality and accountability for system performance and reliabilityCompensation, Benefits, & PerksAs a pre-revenue startup, Endurance Energy offers competitive base salaries and generous equity packages for full-time employees. Final base salary will be determined by an array of factors including internal equity, job-related knowledge, skills, and work experience.A key aspect of our compensation philosophy is that value creation should be aligned with rewards. Right now this means equity is a significant portion of every full-time employee's compensation. As the company matures, there will be continued evolution and changes to the total rewards and total compensation package. What will always be true is that if we win, we win together. Equity is granted to every full-time employee as a meaningful piece of ownership. We believe the people building the company should share directly in the value they create.In addition to a competitive base salary and equity, employees will receive all of our other great benefits and perks, including:Benefits: Health, Dental, and Vision insurance coverageTime Away: Flexible PTO including 12 paid company holidaysGlobal Fieldwork: Travel to fascinating deployment sites along oceanic ridges in locations like the Pacific Northwest, Hawaii, Iceland, Japan, New Zealand, and the AzoresHands-on Experience: Participate in sea trials and deployment operations in partnership with leading oceanographic institutionsCutting-edge Development: Work with technology that spans high-power electronics, marine systems, and clean energyImpactful Work: Help solve one of the world's most pressing challengesDive Certification: Company-sponsored recreational dive certificationOther Perks: Access to the company boat, free meals and snacks, and the list goes on!If you're selected for consideration, a recruiter will be able to discuss in greater detail.