Senior Electric Propulsion Engineer, Cathodes Verified today

About the Role

Apex is seeking a Senior Electric Propulsion Engineer with deep expertise in cathodes to own the design, development, qualification, and production of cathode technology for electric propulsion systems. Building on Apex's in-house Hall-effect thruster capability, you will drive hollow and heaterless cathode development, from emitter physics and thermal-mechanical design through cathode-thruster coupling, life characterization, and design-for-manufacturing at rate.

This is a senior individual-contributor role with significant technical ownership and leadership scope. You will drive key cathode design decisions, lead test and life-qualification campaigns, and work alongside propulsion engineers as we scale EP production. You'll approach cathode development with a clean-sheet, production-first mindset and directly shape the hardware, processes, and infrastructure required to take it from development into flight and serial production.

Responsibilities

• Own end-to-end design and development of hollow and/or heaterless cathodes, 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, and validate them 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 testing in vacuum facilities.
• Drive cathode-thruster integration, optimizing cathode-to-anode coupling, mass flow split, and placement for overall EP system performance and stability.
• Develop cathode erosion, poisoning, and degradation models and perform filtration and contamination-control analysis to 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 scalable production.
• Optimize cathode designs for performance, 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, including cathode heater/keeper drive and PPU interaction, and verify requirements.
• Support build, integration, and test of flight hardware, as well as 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 mentorship to propulsion engineers and contribute to development of Apex's cathode and electric propulsion capability.

Qualifications

• Bachelor's degree in aerospace, mechanical, electrical, plasma/propulsion engineering, applied physics, or related field.
• 6+ 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 3+ years of relevant industry experience. Substantial and demonstrable focus on cathode design, development, and testing required.
• 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 life/wear testing.
• Strong understanding of failure and degradation mechanisms that drive cathode life, including emitter depletion, erosion, poisoning, and contamination, and how to design and test against them.
• Working knowledge of spacecraft propulsion system architecture, propellant feed systems, and PPU interaction.
• Experience owning hardware through design, development, build, and test.
• Ability to decompose requirements and ICDs and communicate clearly across engineering disciplines.
• Must be a U.S. Person as defined by ITAR (22 CFR §120.15): U.S. citizen, lawful permanent resident, refugee, or individual granted asylum.

Nice to Have

• 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.
• Experience supporting failure investigations and resolving issues on flight or qualification hardware.

What We Offer

• Equity in Apex
• 100% company-paid medical, dental, and vision for you and dependents, plus $100k life insurance at no cost
• Starting at 15 days vacation, growing to 20+ days annually, plus 10 paid holidays
• 401(k) plan with 100% match on first 3%, 50% on next 2%
• 8 weeks paid parental leave plus childcare reimbursement up to $350/day for work-related travel
• Daily catered lunch and unlimited snacks
• Monthly office socials, pickleball tournaments, run club, and family gatherings
• Complete desk setup and tools for productivity
• Playa Vista office with in-person collaboration and work-life flexibility
• Stock options for long-term incentives