About the Role

Apex is seeking a Senior Propulsion Engineer with deep expertise in structures and hardware integration to design the propulsion modules that bolt onto Apex spacecraft at scale. You will own the mechanical design of the module, including the structure, mounting and installation of flow controllers, PPUs, and thrusters, and the packaging that turns a set of components into a single, buildable, flight-ready assembly.

What makes this role distinctive is that the propulsion components you're integrating are designed and built in-house at Apex. You'll work directly with the engineers who own our thrusters, cathodes, flow controllers, and PPUs, influencing their mechanical, thermal, and interface design so the components and module are optimized together from the start.

You'll also work closely with our manufacturing team throughout the design cycle, supporting first builds and incorporating feedback from the production floor as we scale. This is a senior individual-contributor role with significant design ownership and technical leadership scope on a team building propulsion modules for serial production.

Responsibilities:

• Own the mechanical design of propulsion modules, including module structures, mounting interfaces, and the installation of flow controllers, PPUs, thrusters, and other propulsion hardware.

• Design module structures to meet vehicle-level structural and environmental requirements, including launch loads, vibration, shock, and thermal environments, while conforming to vehicle ICDs.

• Define and manage the mechanical, thermal, and structural interfaces between propulsion components and the module, and between the module and spacecraft.

• Partner directly with Apex's in-house thruster, cathode, flow controller, and PPU teams to co-optimize component and module design, influencing component mounting, form factor, packaging, and interfaces early in the design cycle.

• Perform and review structural analysis, including hand calculations and FEA, to verify strength, stiffness, and margins and support fracture, fatigue, and random-vibration assessments.

• Design against mass, cost, and power budgets and drive engineering trades to keep the module within its allocations.

• Drive design-for-manufacturing and design-for-assembly to ensure modules are buildable and installable at rate, while designing for serviceability during fill, drain, and ground operations.

• Partner closely with manufacturing and production teams throughout the design cycle, walking designs through with technicians and production engineers, supporting first builds, and resolving issues on the floor.

• Incorporate manufacturing feedback into future design iterations to improve producibility, yield, repeatability, and build time as production scales.

• Own component and assembly drawings, tolerance stack-ups, fastening and torque specifications, and installation work instructions.

• Support the build, integration, and test of flight hardware and contribute to anomaly resolution, failure analysis, and root-cause investigations.

• Drive continuous design improvements across module generations to support future builds and scalable production.

• Provide technical mentorship to mechanical and integration engineers across the team.

Qualifications:

• Bachelor's degree in mechanical, aerospace, or a related engineering field.

• 6+ years of relevant mechanical or aerospace engineering experience with a Bachelor's or Master's degree, OR a Ph.D. in mechanical engineering, aerospace engineering, or a closely related field with 3+ years of relevant industry experience, with substantial experience in structural design and hardware installation/integration.

• Strong command of structural design and analysis, including load paths, strength and stiffness, fasteners and joints, tolerance stack-ups, hand calculations, and FEA.

• Experience designing hardware to survive launch and space environments, including vibration, shock, and thermal environments, and verifying designs against requirements.

• Experience installing and integrating discrete components, such as propulsion, avionics, fluidic, or other spacecraft hardware, into structural assemblies, including interface definition and ICD conformance.

• Proficiency with CAD, engineering drawings, and GD&T, with experience owning hardware from concept through release, build, and test.

• Experience working directly with manufacturing and production teams to transition designs into hardware and resolve build and integration issues.

• Ability to design against mass, cost, and power budgets and make sound engineering trades across competing requirements.

• Ability to communicate clearly and drive technical decisions across engineering, manufacturing, and production 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 with spacecraft propulsion modules, feed systems, or propulsion component integration.

• Experience designing spacecraft or aerospace hardware for serial or high-rate production, including design-for-manufacturing and design-for-assembly.

• Familiarity with electric propulsion components, including thrusters, flow controllers, PPUs, and their mechanical, thermal, fluidic, and electrical interfaces.

• Experience with propellant feed-system routing, fluidic components, and cleanliness/contamination control.

• Experience collaborating directly with component design teams to co-optimize hardware and system-level integration.

• Experience supporting environmental qualification testing, including vibration, shock, and TVAC.

• Experience supporting flight hardware through integration, qualification, launch, and/or on-orbit operations.

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What We Offer For Full-time Employees:

• Shared upside: Receive equity in Apex, letting you benefit from the work you create