Mechanical Engineer II

At Relativity Space, we’re building rockets to serve today’s needs and tomorrow’s breakthroughs. Our Terran R vehicle will deliver customer payloads to orbit, meeting the growing demand for launch capacity. But that’s just the start. Achieving commercial success with Terran R will unlock new opportunities to advance science, exploration, and innovation, pioneering progress that reaches beyond the known.

Joining Relativity means becoming part of something where autonomy, ownership, and impact exist at every level. Here, you're not just executing tasks; you're solving problems that haven’t been solved before, helping develop a rocket, a factory, and a business from the ground up. Whether you’re in propulsion, manufacturing, software, avionics, or a corporate function, you’ll collaborate across teams, shape decisions, and see your work come to life in record time.

Relativity is a place where creativity and technical rigor go hand in hand, and your voice will help define the stories we’re writing together. Now is a unique moment in time where it’s early enough to leave your mark on the product, the process, and the culture, but far enough along that Terran R is tangible and picking up momentum.

The most meaningful work of your career is waiting. Join us.

The Stennis Test team designs, builds, and operates test sites to evaluate Terran R’s high-energy components, rocket engines, and both booster and upper stages. Team members are hands‑on with these large-scale, complex systems, pushing hardware to the limits and directly contributing to flight readiness. The work is fast‑paced, highly operational, and collaborative. No aerospace experience required—we welcome fresh graduates as well as those with hands‑on backgrounds in aviation, automotive, manufacturing, offshore operations, industrial systems, construction, or adjacent industries.

As the Stennis Test site scales to meet growing demand, the team plays a critical role in paving the way for routine, reliable flights of Terran R.

As a Propulsion Test Engineer II, you will work with test stands and test articles (high-energy components, engines, and full stages) for Terran R. You'll have the opportunity to see a heavy‑lift orbital launch vehicle and its many parts come to life through testing. Test and flight articles are designed and built in our Long Beach factory, then sent to Stennis to undergo rigorous testing.

Entry‑level engineers at our Stennis facility work in partnership with experienced engineers, technicians, and welders to build and modify test facilities and participate in test campaigns to evaluate complex rocket hardware. You'll solve a variety of technical problems across broad ranges of timeframe, complexity, and impact, and continuously improve processes to move faster and more efficiently. The role includes three focus areas – Design & Build, Operations, and Integration.

You'll initially be placed on a team in one focus area, with opportunities to work across focuses as you develop in the role, particularly between Operations and Integration which work closely together.

• Design fluid systems (gas, liquid, cryogenic) including Piping & Instruction Diagrams (P&IDs), analysis, and component selection
• Design structural and mechanical systems including 3D modeling, analysis, and fabrication drawings
• Source components and develop detailed fabrication work instructions
• Bring new test stands to life by managing fabrication, activation, and initial operations
• Design and implement upgrades to operational test stands to enable new test capabilities
• Maintain test stands through preventive maintenance and rapid response to anomalies & equipment failures

• Conduct test operations on high-energy components, engines, and stages
• Control test stand and test article through GUIs and automation while monitoring cameras and telemetry
• Conduct flight acceptance, qualification, and development testing campaigns to validate designs and continuously improve the rocket
• Develop and optimize GUIs, procedures, control automation, and data review processes
• Prepare test articles for testing through…