The Space System Payload Engineer will support the design, integration, testing, characterization, calibration, validation, and operation of space payload systems across government, commercial, and defense space programs, with a focus on EO/IR sensors, imaging payloads, scientific instrumentation, and associated mission systems. Responsibilities include supporting initialization and on-orbit calibration and validation activities; coordinating proposed requirements changes, mission analysis, and acquisition teams; attending segment-level design reviews and program management reviews to assess design maturity, requirements compliance, and technical risk; and reviewing acquisition milestone documentation for adequacy, accuracy, and completeness.