Mechanical Propulsion Engineer

Momentus•San Jose, CA

20d•$125,000 - $150,000•Onsite

About The Position

As an early mover in the in-space transportation and infrastructure services, Momentus is at the forefront of the commercialization of space. With an experienced team of aerospace, propulsion, and robotics engineers, Momentus has developed a cost-effective and energy-efficient in-space transport system. OUR PEOPLE Daring problems require daring solutions. We boldly charge into uncharted territory knowing that no matter the outcome we will benefit from the journey and move closer to our goals no matter what. Our teams know that working at Momentus means more than building innovative technology, it means creating entirely new markets in the space economy. We are level-headed, business-minded strategic thinkers intent on providing immediate value to our customers today while simultaneously preparing for the vast possibilities of the future. If this sounds like you, we should talk. JOB SUMMARY We are seeking a Mechanical / Propulsion Engineer with a strong hands-on background in spacecraft hardware and propulsion system development. This hybrid role blends mechanical design, propulsion assembly and testing, spacecraft layout/architecture, and cross-functional collaboration across thermal, structural analysis, and manufacturing teams—with a strong emphasis on AIT execution and spacecraft hardware integration. The ideal candidate thrives in fast-paced, hardware-focused environments and enjoys working from concept through fabrication, test, and flight.

Requirements

Hands-on experience with propulsion system build-up and testing, including fluid systems, heaters, wiring/sensors, or valve integration.
Mechanical design proficiency using modern CAD tools; experience with GD&T, tolerance stack-ups, and drawing release workflows.
Familiarity with spacecraft packaging constraints, tight-tolerance interfaces, and multidisciplinary integration challenges.
Strong documentation skills and the ability to produce clear, concise technical communication.
Effective collaborator in hands-on, cross-functional engineering environments; capable of taking hardware from bench to flight.
BS in Mechanical Engineering, Aerospace Engineering, or related field.
3+ years relevant experience.
3 to 5 years of on-the-job engineering experience.
Desire to contribute to a highly hands-on engineering setting involving design, integration, testing, and flight hardware ownership.
U.S. citizenship, U.S. legal permanent resident status, or protected person status under 8 U.S.C. Â§ 1324b(a)(3) is required.

Nice To Haves

Working understanding of propulsion-system fundamentals, thermal behavior, or fluid dynamics is a plus.
Knowledge of aerospace standards (range safety, RPUG, etc.) or prior experience working with flight hardware.

Responsibilities

Execute hands-on assembly and testing of propulsion systems, including tubing, heaters, sensors, valves, and other fluid-system hardware.
Develop 3D CAD models, detailed part/assembly drawings, tolerance analyses, and integrated layouts optimized for tightly constrained spacecraft environments.
Design spacecraft hardware such as brackets, enclosures, fluid-routing solutions, thermal/mechanical interfaces, and structural components.
Generate models, documentation packages, and work instructions to support AIT (Assembly, Integration & Test) for propulsion and spacecraft mechanical hardware.
Collaborate closely with structural, thermal, analysis, and manufacturing teams to iterate designs through the full engineering lifecycle—from early concepts to flight-ready hardware.
Support propulsion and mechanical test campaigns, including setup, execution, data review, troubleshooting, and documentation.
Apply aerospace standards—including range safety guidelines and RPUG requirements—to ensure compliance, safety, and mission success.
Contribute to process development, continuous improvement, and flight-readiness maturation for mechanical and propulsion subsystems.