Preliminary design of the ORION attitude control system

Abstract

This thesis models the motion of the NPS satellite ORION using the three Euler rotation angles. The simulation program also models aerodynamic drag and gravity gradient torques. Simulations are performed to analyze the effect of changing the inertia ratio on satellite stability and performance. The active nutation control method was also simulated and an example of its operation given. The amount of time required to reduce nutation to an acceptable level was found to be dependent on the initial nutation angle, spin rate, and thruster size. The slower the spin rate, the greater the torque that could be used during a given firing arc resulting in faster nutation control.