An apparatus comprising: A satellite ; and an orbit controller configured to control stationkeeping maneuvers of the satellite , wherein the satellite comprises: a satellite bus having a nadir side configured to face the Earth and a zenith side opposite the nadir side ; a north electric thruster installed toward a north region of the zenith side and oriented downward to produce thrust through a center of mass of the satellite ; a south electric thruster installed toward a south region of the zenith side and oriented upward to produce thrust through the center of mass of the satellite ; an east chemical thruster installed on an east side of the satellite bus ; and a west chemical thruster installed on a west side of the satellite bus ; characterized in that the orbit controller is configured to detect a failure of one of the electric thrusters , and in response to the failure, to: control a burn of the remaining electric thruster proximate to an orbital node ; control a burn of one of the chemical thrusters at 90° ± 5° from the burn of the remaining electric thruster ; and control a burn of the other one of the chemical thrusters at 270° ± 5° from the burn of the remaining electric thruster , wherein the east chemical thruster and the west chemical thruster are configured to produce thrust through the center of mass of the satellite . A satellite ; and an orbit controller configured to control stationkeeping maneuvers of the satellite , wherein the satellite comprises: a satellite bus having a nadir side configured to face the Earth and a zenith side opposite the nadir side ; a north electric thruster installed toward a north region of the zenith side and oriented downward to produce thrust through a center of mass of the satellite ; a south electric thruster installed toward a south region of the zenith side and oriented upward to produce thrust through the center of mass of the satellite ; an east chemical thruster installed on an east side of the satellite bus ; and a west chemical thruster installed on a west side of the satellite bus ; a satellite bus having a nadir side configured to face the Earth and a zenith side opposite the nadir side ; a north electric thruster installed toward a north region of the zenith side and oriented downward to produce thrust through a center of mass of the satellite ; a south electric thruster installed toward a south region of the zenith side and oriented upward to produce thrust through the center of mass of the satellite ; an east chemical thruster installed on an east side of the satellite bus ; and a west chemical thruster installed on a west side of the satellite bus ; characterized in that the orbit controller is configured to detect a failure of one of the electric thrusters , and in response to the failure, to: control a burn of the remaining electric thruster proximate to an orbital node ; control a burn of one of the chemical thrusters at 90° ± 5° from the burn of the remaining electric thruster ; and control a burn of the other one of the chemical thrusters at 270° ± 5° from the burn of the remaining electric thruster , control a burn of the remaining electric thruster proximate to an orbital node ; control a burn of one of the chemical thrusters at 90° ± 5° from the burn of the remaining electric thruster ; and control a burn of the other one of the chemical thrusters at 270° ± 5° from the burn of the remaining electric thruster , wherein the east chemical thruster and the west chemical thruster are configured to produce thrust through the center of mass of the satellite . <EOS>