Abstract: Techniques for performing orbit raising, north-south stationkeeping, east-west stationkeeping, and momentum management with thrusters disposed on a spacecraft are disclosed. The spacecraft includes at least one thruster support mechanism (TSM), including a pointing arrangement and an elongated structural member, the structural member having a long dimension defining a first axis a proximal portion of the structural member is attached to the pointing arrangement each of the thrusters is fixedly coupled with a distal portion of the structural member. The pointing arrangement includes a first, second, and third revolute joint, the first revolute joint being rotatable about the first axis; the third revolute joint being rotatable about a third axis, the third axis being fixed with respect to the spacecraft; and the second revolute joint being rotatable about a second axis, the second axis being orthogonal to each of the first axis and the third axis.

Abstract: Techniques for performing orbit raising north-south stationkeeping, east-west stationkeeping, and momentum management with thrusters disposed on a spacecraft. The spacecraft includes at least one thruster support mechanism (TSM), including a pointing arrangement and an elongated structural member, the structural member having a long dimension defining a first axis a proximal portion of the structural member is attached to the pointing arrangement each of the thrusters is fixedly coupled with a distal portion of the structural member. The pointing arrangement includes a first, second, and third revolute joint, the first revolute joint being rotatable about the first axis; the third revolute joint being rotatable about a third axis, the third axis being fixed with respect to the spacecraft; and the second revolute joint being rotatable about a second axis, the second axis being orthogonal to each of the first axis and the second axis.

Abstract: Apparatus and methods for raising the orbit of a satellite having electric propulsion thrusters, an Earth sensor and an inertial reference sensor such as a gyro. A satellite positioning system generates orbital data and a profile generator generates an ideal electric orbit raising profile of the satellite. The ideal profile is one that the satellite must follow so that the perigee, apogee and inclination of the satellite can be adjusted simultaneously in a mass-efficient manner. A state machine processes the ideal profile and a true anomaly to generate a desired electric orbit raising profile. Steering apparatus generates signals that are used to control the attitude of the satellite to follow the desired profile.

Abstract: Apparatus and methods for raising the orbit of a satellite having electric propulsion thrusters, an Earth sensor and an inertial reference sensor such as a gyro. A satellite positioning system generates orbital data and a profile generator generates an ideal electric orbit raising profile of the satellite. The ideal profile is one that the satellite must follow so that the perigee, apogee and inclination of the satellite can be adjusted simultaneously in a mass-efficient manner. A state machine processes the ideal profile and a true anomaly to generate a desired electric orbit raising profile. Steering apparatus generates signals that are used to control the attitude of the satellite to follow the desired profile.

Abstract: A practical orbit raising method and system wherein a satellite quickly escapes the Van Allen radiation belts and payload mass and mission life are maximized. A satellite is launched that contains high thrust chemical propulsion thrusters, high specific impulse electric propulsion thrusters and a solar array. The satellite quickly escapes the Van Allen radiation belts by firing the high thrust chemical propulsion thrusters at apogees of intermediate orbits, starting from the transfer orbit initiated by a launch vehicle, to successively raise the perigees until the perigee clears the Van Allen radiation belts. The payload mass and mission life are maximized by firing high specific impulse electric propulsion thrusters to raise the satellite to near synchronous orbit, while steering the thrust vector and solar array to maintain the sun's illumination on the solar array. The chemical and/or electric propulsion thrusters are then fired to achieve geosynchronous orbit.