Patent ID: 6032904
Filing Date: 2000-03-07
Classification: B64G

Abstract:
A system for performing at least one of a plurality of operations including orbit raising, north-south station keeping, and selective unloading of momentum wheels used for controlling the orientation of a three-axis stabilized spacecraft having roll, pitch, and yaw axes, and having a north face and a south face which when on station in orbit about the earth generally face north and south, respectively, said system comprising:first and second thrusters having first and second thrust vectors, respectively;first support means for mounting said first thruster adjacent said north face, said first thruster being positioned a spaced distance away from said north face in a first direction parallel to the pitch axis and a spaced distance away from the pitch axis in a second direction normal to the pitch axis;second support means for mounting said second thruster adjacent said south face, said second thruster being positioned a spaced distance away from said south face in a third direction opposite the first direction and a spaced distance away from the pitch axis in the second direction; andgimbal means pivotally mounting said first and second thrusters on said first and second support means, respectively, for selectively positioning the thrust vectors of said first and second thrusters, said gimbal means including a gimbal system including:a first gimbal for mounting said first thruster for pivotal movement about an axis parallel to the roll axis between a stowed inoperative position through an orbit raising position at which the first thrust vector is generally parallel to the yaw axis to a north-south station keeping position at which the first thrust vector is generally aligned with the center of mass of the spacecraft; anda second gimbal for mounting said second thruster for pivotal movement about an axis parallel to the roll axis between a stowed inoperative position through an orbit raising position at which the second thrust vector is generally parallel to the yaw axis to a north-south station keeping position at which the second thrust vector is generally aligned with the center of mass of the spacecraft.