Senior Mechanical Engineer

About EnduranceEndurance 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 First Round Capital and Point72 Ventures, our founding team includes veterans from SpaceX, Helion, and Robinhood. We have completed multiple deep ocean deployments and are launching our generation pilot this year. By leveraging manufacturing scale, efficient drilling, and latent cooling on the seafloor, we are pioneering a new category of energy that outperforms traditional sources on both environmental impact and cost.What You'll Be DoingAs 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 reliabilityBenefits & PerksGlobal 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 challengesCompetitive Compensation: Comprehensive salary (150K-250K) and equity packagesBenefits: Vision, Dental, Health insurance coverageDive Certification: Company-sponsored recreational dive certification