Staff Electric Propulsion Engineer, Cathodes Verified today

About the role

Apex is seeking a Staff Electric Propulsion Engineer with deep expertise in cathodes to own the design, development, qualification, and production of cathode technology at the heart of our electric propulsion systems. This is a senior individual-contributor role with technical leadership scope. You will set the cathode technical roadmap, drive key design decisions, stand up and run cathode test and life-qualification campaigns, and mentor propulsion engineers as we scale EP production.

What you will do

• Own the end-to-end design of hollow and/or heaterless cathodes for our electric propulsion systems, including emitter selection, keeper and orifice geometry, heater design, and thermal-mechanical packaging.
• Develop physics-based and empirical models to predict cathode performance, discharge behavior, thermal margins, and life, validated against test data.
• Define and execute cathode test and life-qualification campaigns, including ignition and conditioning, coupling voltage characterization, thermal cycling, plume/plasma diagnostics, wear testing, and long-duration life tests in vacuum facilities.
• Drive cathode-thruster integration, optimizing cathode-to-anode coupling, mass flow split, and placement for overall EP system performance and stability.
• Establish cathode erosion, poisoning, and degradation models; perform filtration and contamination-control analysis; and demonstrate compliance with propulsion budgets for life, power, thermal, leak, and contamination.
• Select emitter and structural materials and processes, including LaB6, BaO-impregnated tungsten, and refractory metals, and qualify them for spaceflight and high-rate production.
• Optimize cathode designs for weight, cost, manufacturability, and repeatability, and develop work instructions, process flows, and AI&T procedures required to build them at rate.
• Partner with systems, power electronics, thermal, structures, and avionics teams to define interfaces and verify requirements.
• Support the build, integration, and test of flight hardware, launch campaigns, on-orbit performance evaluation, and anomaly resolution.
• Lead failure analysis, root-cause investigations, and continuous design improvements to support future builds and scalable production.
• Provide technical leadership and mentorship to propulsion engineers and help build Apex's cathode and broader electric propulsion capability.

Requirements

• U.S. Person (U.S. citizen, lawful permanent resident, refugee, or individual granted asylum) as defined by ITAR (22 CFR §120.15).
• Bachelor's degree in aerospace, mechanical, electrical, plasma/propulsion engineering, applied physics, or related field.
• 10+ years of relevant electric propulsion experience with a Bachelor's or Master's degree, OR a Ph.D. in electric propulsion, plasma physics, applied physics, or closely related field with 5+ years of relevant industry experience, with substantial and demonstrable focus on cathode design, development, and testing.
• Deep, hands-on knowledge of hollow and/or heaterless cathode physics, including thermionic emission, emitter materials, plasma discharge behavior, keeper/orifice design, and cathode coupling to Hall or ion thrusters.
• Experience planning and executing cathode or EP test campaigns in vacuum facilities, including plasma diagnostics, performance measurement, and long-duration life/wear testing.
• Strong understanding of failure and degradation mechanisms that drive cathode life, including emitter depletion, erosion, poisoning, and contamination.
• Working knowledge of spacecraft propulsion system architecture, propellant feed systems, and range safety requirements.
• Ability to decompose requirements and ICDs and communicate clearly across engineering disciplines.

Preferred experience

• Direct experience taking a cathode or EP thruster from development through flight qualification and on-orbit operation.
• Experience with heaterless cathode ignition and conditioning schemes.
• Experience with alternative propellants, including krypton and other non-xenon EP propellants, and their effects on cathode life and operation.
• Familiarity with PPU/cathode drive electronics and power interface definition.
• Design-for-manufacturing experience bringing propulsion hardware into serial or high-rate production.
• Experience with EP environmental qualification, including vibration, TVAC, and EMI testing of flight propulsion hardware.

Compensation and benefits

Compensation is set by role, level, location, and market data. Full-time employees receive equity, stock options, 100% company-paid medical/dental/vision for you and dependents, $100k life insurance at no cost, starting 15 days vacation growing to 20+ days annually, 10 paid holidays, 100% match on first 3% of 401(k) and 50% on next 2%, 8 weeks paid parental leave, childcare reimbursement up to $350/day for work-related travel, daily catered lunch and unlimited snacks.

Employment details

Full-time position based in Los Angeles, CA (Playa Vista office).