The Avionics of a spacecraft work to take information gathered by the Guidance, Navigation, and Control Subsystem and output commands to the other subsystems to complete the mission objective.

The Avionics of a spacecraft work with the Data Handling Subsystem to create the Flight Computer which handles the commands and computations for flight. The Watchdog of the data handling system helps check up on the avionics system, and performs resets either routinely, as needed, or both. Power Boards monitor power levels of batteries so the Avionics may use and conserve power as needed. the ACB and Peripheral Controllers allow the spacecraft to communicate with the sensors needed for spaceflight.

The Avionics of a spacecraft work with the landing subsystem to determine the optimum timing to detach from the satellite, deploy landing measures, and to optimize steering and control during descent.

The Avionics of a spacecraft work with the Mechanisms Subsystem to collect and communicate data both to store and to output in the form of mechanical motions or actions.