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 for our electric propulsion systems. You will be the technical authority on hollow and heaterless cathode design, 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 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.

Responsibilities

• Own end-to-end design 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, 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, 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; 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; qualify them for spaceflight and high-rate production.
• Optimize cathode designs for weight, cost, manufacturability, and repeatability; develop work instructions, process flows, and AI&T procedures for high-rate production.
• Partner with systems, power electronics, thermal, structures, and avionics teams to define interfaces, including cathode heater/keeper drive and PPU interaction.
• Support build, integration, and test of flight hardware; support 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 electric propulsion capability.

Qualifications

• 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 (e.g., SSCMAN 91-710).
• Ability to decompose requirements and ICDs and communicate clearly across engineering disciplines.
• Must be a U.S. Person (U.S. citizen, lawful permanent resident, or protected individual) as defined by ITAR (22 CFR 120.15).

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.

What We Offer

• Equity in Apex
• 100% company-paid medical, dental, and vision for you and your 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
• Equipment and tools to support productivity