Senior Mechanical Engineer (Electromechanical)

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, 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.

Every watt the plant produces passes through electromechanical hardware. The power electronics live on the seafloor, so they are packaged in pressure-compensated, fluid-filled housings, cooled by seawater, and connected to the rest of the plant through high-power busswork and wet-mate and dry-mate connectors we design in-house. Every valve the plant actuates and every mechanism that moves is driven by subsea actuators and motors. We design, build, test, and deploy all of it. In this role you will focus on the hardware where electricity, fluid, and pressure meet: electronics cooling and thermal management; subsea packaging of high-power electronics, including dielectric fluids, compensation, penetrators, and feedthroughs; high-power busswork and electrical interfaces; wet-mate and dry-mate connectors; and actuators, motors, pumps, and mechanisms with their dynamic seals and magnetic couplings. You will share that scope with a few other engineers, and specific hardware will be yours end to end. You will work most closely with our power electronics engineers.

Help deliver the electromechanical hardware for our first commercial system, the first subsea geothermal plant to put power on a grid: the cooled, pressure-compensated electronics packaging, the busswork and connectors that carry its power, and the actuators that run it, all designed, built, qualified, and operating on the seafloor.

Our mechanical engineering team is a small group of senior and principal engineers who split the plant's hardware between them. Each engineer owns their hardware end to end: requirements, design, drawings, build, test, and deployment. Principal engineers own the plant architecture, and you will be part of those decisions. We are looking for people who have built hardware, debugged it in the lab or the field, and want to own the result.

• Own specific electromechanical hardware end to end: electronics cooling and enclosures,

busswork and connectors, or actuators and mechanisms

• Design high-power electrical interfaces: busswork, wet-mate and dry-mate connectors, contact and insulator design, dielectric sealing, and mate and demate mechanics

• Design subsea packaging for high-power electronics: fluid-filled and pressure-compensated enclosures, dielectric fluid selection, penetrators, and feedthroughs

• Design electronics cooling and thermal management: heat rejection from converter stacks through the enclosure to seawater, cold plates, and immersion cooling

• Design subsea actuators, motors, pumps, and mechanisms: dynamic and rotating seals,

magnetic couplings, position feedback, and fail-safe behavior

• Translate electrical requirements (voltage, current, creepage, thermal) into mechanical

designs, working day to day with the power electronics engineers

• Design and build test setups for high voltage under hydrostatic pressure, insulation resistance, partial discharge, thermal performance, and long-duration immersion

• Lead root-cause investigations on connector, enclosure, and actuator failures and implement corrective actions

• Define interfaces with the valves and primary structures owned by your peers

• Work directly with machine shops, molders, and specialty suppliers on contacts, insulators, seals, and precision mechanisms

• Contribute to plant-level electrical architecture and packaging decisions alongside our principal engineers

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

assemblies

• Bachelor's degree in mechanical engineering, electrical engineering, or a related engineering discipline

• 6+ years of professional experience designing electromechanical hardware (connectors,

actuators, mechanisms, or electronics packaging) for demanding environments

• Ownership of at least one electromechanical component from concept through qualification and fielded use

• Experience designing subsea electrical connectors, penetrators, busswork, or actuators, or equivalent experience with spacecraft mechanisms, downhole tools, or power electronics packaging for aerospace or automotive

• Hands-on experience with dielectric fluids, pressure compensation, and sealing high voltage against seawater

• Experience with dynamic and rotating seals, magnetic couplings, and the failure modes of

mechanisms in long-duration service

• Experience with thermal management of power electronics, including liquid- or immersion- cooled systems

• Working knowledge of high-voltage design and test: creepage and clearance, insulation

resistance, partial discharge

• Experience sizing motors and actuators and integrating electronics into mechanical assemblies

• Experience at a small or fast-moving hardware organization, where you had to make good

engineering decisions with incomplete information and limited resources

• A track record of taking on increasing responsibility and delivering something difficult early in your career

• Experience on an engineering competition team (Formula SAE, Baja SAE, RoboSub, rocketry, or similar) or an equivalent self-directed hardware project