The Vanguard system is composed of many subsystems.  Due to this a number of microcontrollers are used. Each subsystem has a controller designed to perform a specific for that subsystem. These controllers take instructions from the main controller. The main controller is programmed to monitor the inputs it receives. These inputs can come from the subsystem controllers or the earth based controllers. The main controller is a processor (CPU) for image processing capabilities. The software to coordinate these actions is the most important aspect of this control design.

 

Fig. Main Computer Block Diagram