In this textbook, investigation and modeling of enhanced attitude and orbit determination and control systems is conducted which consists of sensors and control actuators in an effort to design an optimized controller. A three-axis star tracker and three reaction wheels are used in order to solve the spacecraft three-axis attitude and control estimation. In the case of sensor malfunction, three-axis attitude estimation is obtained using only two-axis star tracker sensor that utilizes a flexible and mathematically effective Discrete Kalman Filter (DKF). Development of an optimized Proportional-Integral-Derivative (PID) control law is desired mainly due to its simplicity and robustness. Control parameters of the PID controller are selected optimally by comparing the results from Gravitational Search Algorithm (GSA), Backtracking Search Optimization Algorithm (BSA) and Particle Swarm Optimization (PSO) methods to minimize the error. In all optimization methods, the objective function was considered the mean absolute error (MAE) of the controller error.