Patent ID: 6186446
Filing Date: 2001-02-13
Classification: B64G

Abstract:
A satellite control for an electric propulsion system, said propulsion system used for transferring a satellite from a first orbit to a second orbit in accordance with a predetermined schedule which includes continuous adjustment of the direction of electrical propulsion to maintain optimum electrical propulsion system efficiency, said satellite being oriented with reference to orthogonal x, y, and z axis, said control including a ground control computer and further comprising:a system of electric propulsion thrusters mounted on the satellite for generating a resultant thrust in a predetermined direction;an onboard inertial reference for generating data indicative of the current attitude of the satellite;an onboard attitude control for processing said schedule of optimized thruster attitude data, said data relating to the transfer of the satellite through a series of transition orbits from said first orbit to said second orbit, said attitude control comparing the attitude indicated by the inertial reference to the thruster attitude data and generating an attitude adjustment for moving the satellite to the desired thruster attitude, said adjustment including a component which moves the satellite so that the sun position is aligned with the xz plane of said orthogonal axis';attitude actuators for adjusting the position of the satellite in accordance with the thruster attitude adjustment;a solar array mounted on the satellite for rotation about an axis coincident with the y axis of the satellite;a solar array control for generating array position data indicative of the rotational adjustment of the array required to align the array substantially perpendicular to the sun; anda solar array actuator connected to the array to drive the array in rotation about its axis in accordance with the array adjustment data from the solar array control.