Systems Engineer, Spacecraft Design & Simulation

At Vast, our mission is to contribute to a future where billions of people are living and thriving in space. Vast is developing next-generation space stations to ensure a continuous human presence in space for America and its allies, enabling advanced microgravity research and manufacturing, and unlocking a new space economy for government, corporate, and private customers. Using an incremental, hardware-rich and low-cost approach, Vast is rapidly developing its multi-module Haven Station. Haven Demo’s 2025 success made Vast the only operational commercial space station company to fly and operate its own spacecraft. Next, Haven-1 is expected to become the world’s first commercial space station when it launches, followed by additional Haven modules to enable permanent human presence by 2030. Our team is all-in, committed to executing our mission safely and on time. If you want to work with the most talented people on Earth furthering space exploration for humanity, come join us.Vast is seeking a Systems Engineer, Spacecraft Design & Simulation to own the spacecraft simulation toolchain that is the foundation of our mission factory — the software infrastructure that will enable us to scale from our first 10-satellite demo launch to hundreds of spacecraft per year. This will be a full-time, exempt position located in our Long Beach location. About the role:We're building a mission factory — software infrastructure that dramatically reduces the time from customer contract to payload on orbit. The foundation is a simulation and digital twin toolchain that serves as the primary engineering record. Requirements, budgets, design parameters, and trade study results all live in this toolchain. It includes spacecraft power/thermal/ADCS simulation, orbital constellation analysis, communications link budgets, and actuator trade studies. This is model-based systems engineering as it should work — requirements, budgets, and design parameters live in executable models that compute and validate, not in static documents. A working prototype exists today — you'll evaluate it, determine whether to extend it or redesign it, and own the toolchain as we scale from our first 10-satellite demo launch to hundreds of spacecraft per year.This is a spacecraft systems engineering role, not a software engineering role. You define the governing equations, boundary conditions, and expected behavior for each model. You build and maintain a rigorous validation suite — hand calculations, independent tool cross-checks, and edge case analysis — that serves as the quality gate for every change. We use AI code generation tools to accelerate implementation, but the engineering judgment, validation methodology, and physics expertise are yours.Responsibilities: Own and evolve the spacecraft design, simulation, and digital twin toolchain — power, thermal, ADCS, orbital mechanics, constellation coverage, link budgets, mass and design margin trackingMake the toolchain the hub of the engineering organization — every discipline (thermal, GNC, power, structures) should be able to run trade studies and assess design changes quickly as the program evolvesDrive design trades and architecture decisions through analysis — your models are how the team knows whether the power budget closes, whether the thermal architecture works, and whether we meet customer requirementsEnable rapid iteration as customer requirements and the design evolve — the toolchain must keep pace with the program so engineers can assess impact immediately, not wait weeks for analysisMaintain the digital twin as the program's engineering record — requirements, budgets, design parameters, and trade study results live hereBuild and maintain a rigorous validation suite — hand calculations, independent tool cross-checks, edge case analysis, and regression testing for every physics modelTrain and support the engineering team so they can self-serve on trade studies and analysisMinimum Qualifications:Bachelor's degree in Aerospace Engineering, Mechanical Engineering, Electrical Engineering, Physics, or a related technical discipline4+ years of spacecraft systems engineering or mission analysis experienceSpacecraft systems engineer with broad subsystem knowledge — you understand power, thermal, ADCS, and orbital mechanics well enough to catch errors in a simulationStrong analytical skills — you can set up a hand calculation for a thermal equilibrium problem, a power budget across an orbit, or a pointing error budgetRigorous validation mindset — you're the person who asks “how do we know this is right?” and builds the test to prove itComfortable with AI-assisted development workflowsGeneralist background — prior experience at a small-sat company, research lab, or mission design role where you touched multiple subsystemsCross-functional collaboration skills — you'll work with every discipline lead to capture their domain knowledge and translate it into validated modelsComfortable reading and reviewing code — you don't need a software engineering background, but you should be able to understand what code is doing and catch errorsPreferred Skills & Experience:Able to obtain a security clearanceExperience building or maintaining spacecraft simulation toolsFamiliarity with orbital mechanics (Kepler solver, J2 perturbations, eclipse geometry)Familiarity with CMG dynamics, quaternion attitude propagationExperience with data visualization tools or librariesDemonstrated use of AI-assisted code generation tools on an engineering project — show us what you builtRequirements management and verification experience on a spacecraft missionExperience with MBSE tools or model-based development methodologiesExperience scaling engineering tools or analysis workflows across a growing teamExperience developing validation and verification test suites for engineering toolsPay Range: California$112,340—$159,468 USDCOMPENSATION AND BENEFITSBase salary will vary depending on job-related knowledge, education, skills, experience, business needs, and market demand. Salary is just one component of our comprehensive compensation package. Full-time employees also receive company equity, as well as access to a full suite of compelling benefits and perks, including: medical, dental, and vision coverage for employees and dependents, generous paid time off; up to 20+ days of vacation for exempt staff and up to 10+ days of vacation for non-exempt staff with the ability to cash-out unused vacation annually, paid parental leave, short and long-term disability insurance, life insurance, access to a 401(k) retirement plan, ClassPass credits, personalized mental healthcare through Spring Health, and other discounts and perks. We also take pride in offering exceptional food perks, with snacks, drip coffee & onsite barista, cold drinks, and dinner meals remaining free of charge, and lunch subsidized as part of Vast’s ongoing commitment to providing high-quality meals for employees.U.S. EXPORT CONTROL COMPLIANCE STATUSThe person hired will have access to information and items subject to U.S. export controls, and therefore, must either be a “U.S. person” as defined by 22 C.F.R. § 120.62 or otherwise eligible for deemed export licensing. This status includes U.S. citizens, U.S. nationals, lawful permanent residents (green card holders), and asylees and refugees with such status granted, not pending.EQUAL OPPORTUNITYVast is an Equal Opportunity Employer; employment with Vast is governed on the basis of merit, competence and qualifications and will not be influenced in any manner by race, color, religion, gender, national origin/ethnicity, veteran status, disability status, age, sexual orientation, gender identity, marital status, mental or physical disability or any other legally protected status.