Senior GNC Simulation Engineer in Long Beach

Job DescriptionJob Description 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. About the Team: The Guidance, Navigation, and Control (GNC) and Performance teams are responsible for defining and analyzing how Terran R flies, from liftoff to landing. The work combines a variety of disciplines such as advanced modeling, orbital mechanics, software development, and dynamic systems to optimize every phase of flight. You'll develop flight algorithms, simulate trajectories, and model Terran R's dynamic behavior across mission profiles. Whether you're early in your career or a seasoned expert, you'll have the opportunity to own critical pieces of the system, influence design, and see your work fly. The department is part of the Integrated Performance team, uniting key disciplines to drive performance at every stage of the mission. About the Role: You will be a key contributor to the 6DOF simulation used for GNC algorithm development, Monte Carlo analysis, and hardware-in-the-loop (HITL) testing Work with analysis and hardware teams to develop and integrate subsystem models into the 6DOF simulation Implement numerical solvers and physics models Develop simulation configuration, scheduling, logging, and Monte Carlo capabilities Develop simulation interfaces with GNC algorithms Maintain and improve the development environment for simulation users Contribute to other cross‑functional software packages at Relativity About You: An undergraduate or graduate degree (BS/MS/PhD) in engineering, physics, mathematics or related disciplines 5+ years of relevant full‑time work experience Proficiency with compiled (e.g. C++, Rust) and scripted (e.g. Python) Experience developing physics-based simulations of aerospace vehicles Ability to work in a fast paced and intense startup environment Ability to complete projects with ownership of end‑to‑end solutions with a high degree of independence Nice to haves but not required: Familiarity with the design and analysis of launch vehicles or space systems Experience developing aerospace vehicle simulations that interface with GNC algorithms and/or hardware-in-the-loop (HITL) testing Experience implementing high-performance computing (HPC) solutions Experience implementing software development practices and workflows such as Docker, continuous integration (CI), and continuous deployment (CD) At Relativity Space, we are committed to transparency and fairness in our compensation practices. Actual compensation will be determined based on experience, qualifications, and other job-related factors. Compensation is only one part of our total rewards package. Relativity Space offers competitive salary and equity, a generous PTO and sick leave policy, parental leave, an annual learning and development stipend, and more! To see some of the benefits & perks we offer, please visit here. Hiring Range:$148,000—$203,500 USD We are an equal opportunity employer and value at our company. We do not discriminate on the basis of , , , , , , , marital status, veteran status, or status. If you need a reasonable accommodation, please contact us at View email address on click.appcast.io. #J-18808-Ljbffr