Senior Mechanical Engineer

Endurance 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, and Robinhood. We have completed multiple deep-ocean deployments 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 both environmental impact 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.

• Architect and design critical mechanical systems from concept through offshore deployment

• Perform first-principles analysis of loads, thermal behavior, sealing strategies, and failure modes

• Design pressure-tolerant hardware, structural systems, and thermal interfaces for subsea environments

• Develop robust sealing and corrosion mitigation strategies for long-duration saltwater exposure

• Design assemblies including pressure housings, structural frames, fluid systems, and deployment mechanisms

• Create detailed 3D CAD models, drawings, and tolerance stacks for complex hardware

• Build and test prototypes to validate mechanical performance and uncover failure modes

• Design and execute qualification tests including pressure testing, fatigue testing, thermal cycling, and corrosion exposure

• Investigate hardware failures and implement permanent design improvements

• Work directly with fabricators and suppliers to build hardware quickly and correctly

• Collaborate with electrical, drilling, and subsea systems teams to ensure clean system integration

• Participate in sea trials and field deployments to validate hardware performance

• 6+ years designing and delivering complex mechanical systems in demanding environments

• Demonstrated ownership of hardware from early concept through testing and deployment

• Strong first-principles understanding of mechanics, materials, thermal systems, and failure modes

• Deep proficiency in 3D CAD and mechanical design of complex assemblies

• Experience designing hardware for harsh environments (subsea, aerospace, automotive, energy, robotics, etc.)

• Proven ability to debug mechanical failures through testing and root-cause analysis

• Strong intuition for structural load paths, sealing strategies, corrosion mitigation, and thermal management

• Comfort working hands-on with hardware in a lab or shop environment

• Ability to move quickly, close loops, and make good engineering decisions under uncertainty

• High ownership mentality and accountability for system performance and reliability

• Global Fieldwork: Travel to fascinating deployment sites along oceanic ridges in locations like the Pacific Northwest, Hawaii, Iceland, Japan, New Zealand, and the Azores

• Hands-on Experience: Participate in sea trials and deployment operations in partnership with leading oceanographic institutions

• Cutting-edge Development: Work with technology that spans high-power electronics, marine systems, and clean energy

• Impactful Work: Help solve one of the world's most pressing challenges

• Competitive Compensation: Comprehensive salary (150K-250K) and equity packages

• Benefits: Vision, Dental, Health insurance coverage

• Dive Certification: Company-sponsored recreational dive certification