Senior Mechanical Engineer (Valves & Components)

Endurance Energy • Seattle, WA

2d • $170,000 - $230,000

About The Position

Endurance is developing modular subsea geothermal power plants that circulate 250–350 °C geothermal fluid through a closed loop 1–3 km underwater, where ambient seawater pressure is 100–300 bar. The Senior Mechanical Engineer will own fluid components—including isolation, check, control, and relief valves; seats and seals; fittings, manifolds, compensators; and filters and strainers—designed to operate for years in demanding hot, corrosive, high-pressure conditions. Most of the work is clean-sheet design, including component sizing, material selection, and designing and building hot-fluid test rigs to qualify hardware.

The engineer will share component scope with other engineers and own specific components end to end, from requirements and design through drawings, build, qualification, and deployment. The role involves close collaboration with principal engineers on plant-level architecture and with machine shops and specialty suppliers. In the first year, the engineer will help deliver the fluid-component set for Endurance’s first commercial system, which will be designed, built, qualified in the company’s test cells, and operated on the seafloor. Components developed for that system will establish a baseline for future plants.

Requirements

• Bachelor’s degree in mechanical engineering, aerospace engineering, or a related engineering discipline.
• At least 6 years of professional experience designing, testing, or manufacturing fluid-control hardware such as valves, regulators, seals, or pumps for demanding environments.
• Ownership of at least one fluid component from concept through qualification and fielded use.

Nice To Haves

• Experience designing propulsion valves or flow-control devices for rocket engines or feed systems, including cryogenic, hot-gas, or high-pressure applications.
• Equivalent depth in subsea oil and gas components (trees, chokes, API 17D/6A), high-temperature steam or geothermal hardware, or nuclear-grade pressure-boundary components.
• Strong understanding of seal and seat design, leakage physics, and seal behavior across large temperature ranges.
• Strong fundamentals in solid mechanics, fluid dynamics, heat transfer, and materials, with comfort using hand calculations and FEA.
• Experience designing and running qualification and acceptance tests and analyzing the results.
• Hands-on experience with GD&T, design for manufacture in hard-to-machine alloys, and work in a machine shop and test cell.
• Experience at a small or fast-moving hardware organization, making engineering decisions with incomplete information and limited resources.
• A track record of taking on increasing responsibility and delivering difficult work early in a career.
• Experience on an engineering competition team (Formula SAE, Baja SAE, RoboSub, rocketry, or similar) or an equivalent self-directed hardware project.

Responsibilities

• Own specific fluid components in the working-fluid loop from requirements through design, qualification, and field performance.
• Design isolation, check, control, and relief valves and sealing systems for 250–350 °C fluid with 100–300 bar external seawater pressure.
• Select and qualify materials for hot chloride, sulfide, and silica-scaling environments, including nickel alloys, duplex stainless steels, titanium, coatings, and hardfacing.
• Perform first-principles flow, thermal, and structural analysis, including seat loads at temperature, thermal growth and tolerance stacks, pressure-boundary margins, and fatigue.
• Design and build hot-fluid test rigs; run pressure, endurance, leak, thermal-cycling, and corrosion tests to qualify components.
• Lead root-cause investigations on test and field hardware and implement corrective actions.
• Define interfaces with actuators and pressure boundaries owned by peers.
• Work directly with machine shops and specialty suppliers on tight-tolerance parts in exotic alloys.
• Contribute to plant-level fluid-system architecture decisions alongside principal engineers.
• Create detailed 3D CAD models, drawings, and tolerance stacks.

Benefits

• Competitive base salary and generous equity packages for full-time employees; equity is granted to every full-time employee as a meaningful ownership stake.
• Health, dental, and vision insurance coverage.
• Flexible PTO, including 12 paid company holidays.
• Travel to deployment sites along oceanic ridges, including locations such as the Pacific Northwest, Hawaii, Iceland, Japan, New Zealand, and the Azores.
• Participation in sea trials and deployment operations in partnership with leading oceanographic institutions.
• Company-sponsored recreational dive certification.
• Access to the company boat, free meals, and snacks.

What This Job Offers

• Job Type: Full-time
• Career Level: Senior