GNC Engineer

Hop Aero is a venture-backed startup building rockets that deliver cargo anywhere on Earth in minutes.Our mission is to enable resilient global logistics to protect and improve our way of life.Our founding team has prior experience founding a satellite startup and taking it to orbit, launching 20+ Falcon 9 missions at SpaceX, and leading engineering teams at some of the world’s most advanced aerospace organizations. The company is well-capitalized through venture funding and government contracts. About the roleWe’re hiring a GNC Engineer to own guidance, navigation, control (GNC), and flight-dynamics development for Hop Aero’s reusable rocket cargo vehicles.This is a foundational technical role. You will build the models, simulations, algorithms, and test infrastructure that take our vehicles from the pad through ascent, coast, re-entry, and precision propulsive landing. We are looking for someone with deep intuition for flight dynamics and control of real vehicles, not just someone who can build simulations in isolation. You should be comfortable moving between first-principles modeling, Monte Carlo analysis, controller design, actuator and sensor limitations, software implementation, HIL testing, and flight-test data. You will have significant ownership over vehicle behavior. The models you build will directly inform vehicle architecture, actuator sizing, sensor selection, flight software, test planning, and ultimately whether the vehicle flies. Job DescriptionServe as the responsible engineer for guidance, navigation, control, and flight dynamicsBuild and maintain high-fidelity 6-DoF vehicle simulations from first principlesModel vehicle aerodynamics, propulsion, mass properties, sensors, actuators, winds, disturbances, and uncertaintiesDevelop guidance and control algorithms for ascent, coast, attitude reorientation, powered descent, and vertical landingSelect and implement appropriate control architectures including PID, LQR, MPC, gain scheduling, or other methods where appropriateDevelop navigation and state-estimation systems using inertial, GNSS, vision, radar, altimetry, and other sensing modalitiesPerform Monte Carlo analysis and define vehicle dispersions, stability margins, and control authority requirementsTranslate simulation results into requirements for propulsion, TVC, RCS, avionics, structures, and vehicle configurationIntegrate GNC algorithms with flight software and embedded systemsDevelop SIL and HIL environments to validate flight software and vehicle behavior prior to testSupport tethered tests, hover tests, hop tests, and full flight-test campaignsAnalyze flight data, identify model discrepancies, and continuously improve simulation fidelityOwn GNC technical risks through design reviews, test-readiness reviews, and flight-readiness reviewsWork in person with the team at our shop in Orange, CA Requirements5-10 years of relevant experience in GNC, flight dynamics, controls, or closely related fieldsDeep understanding of rigid-body dynamics, flight mechanics, guidance, controls, and state estimationDemonstrated experience building and using high-fidelity 6-DoF simulationsExperience developing control systems for real flight vehiclesStrong understanding of actuator dynamics, sensor limitations, latency, uncertainty, and real-world nonlinearitiesExperience with MATLAB/Simulink and Python and/or C++Ability to translate simulation and analysis into real vehicle requirements and design decisionsExperience validating models and algorithms against hardware or flight-test dataAbility to work directly with propulsion, avionics, flight software, structures, and test teamsWillingness to participate directly in vehicle integration and flight-test operationsMust be a US Person under ITAR - Hop Aero will not sponsor visas for this role. Nice to haveExperience with vertical takeoff and landing vehicles, launch vehicles, missiles, high-speed aircraft, or spacecraftExperience taking a vehicle from first simulation through hover or flight testExperience with thrust-vector control, reaction-control systems, or powered descentExperience with terrain-relative navigation, machine vision, or GPS-denied navigationExperience designing or operating SIL and HIL test environmentsExperience with Monte Carlo dispersion analysis and flight-envelope expansionExperience on DoD or U.S. Air Force flight programsPrior experience at a fast-moving aerospace or hardware startup What we offerCompetitive salary and meaningful stock optionsHealthcare, office meals & snacksDirect collaboration with founders & engineers with rich flight heritageSignificant technical ownership from day oneThe opportunity to define the GNC architecture of a new class of flight vehicleFast upward mobility as the company grows Even if you don’t meet every single requirement, we’d still love to hear from you. Greatness looks different in every one of us - and we need the best tackling this problem.