Apparatus and methods for controlling a spacecraft for a transfer orbit. The spacecraft includes a momentum subsystem that stores angular momentum relative to a center of mass of the spacecraft, and a propulsion subsystem that includes electric thrusters. A controller identifies a target spin axis for the spacecraft, determines gimbal angles for electric thruster(s) that so that thrust forces from the electric thrusters are parallel to the target spin axis, and initiates a burn of the electric thruster(s) at the gimbal angles. The controller controls the momentum subsystem to compensate for a thruster torque produced by the burn of the electric thrusters. The momentum subsystem is able to produce a target angular momentum about the center of mass, where a coupling between the target angular momentum and an angular velocity of the spacecraft creates an offset torque to counteract the thruster torque.

A thrust vector control system is provided. The thrust vector control system may comprise an anti-stall hydraulic pump configured to deliver hydraulic fluid to at least one actuator, wherein each actuator may be configured to move an exhaust nozzle of a space vehicle. The anti-stall hydraulic pump may provide thermal conditioning to the thrust vector actuation control system during ground operation and/or periods of low output operation.

A propulsion system for the orbit control of a satellite in Earth orbit driven at a rate of displacement along an axis V tangential to the orbit comprises two propulsion modules, fixed to the satellite, and facing one another relative to the plane of the orbit, each of the propulsion modules comprising, in succession: a motorized rotation link about an axis parallel to the axis V; an offset arm; and a plate supporting two thrusters, suitable for delivering a thrust on an axis, arranged on the plate on either side of a plane P at right angles to the axis V passing through a center of mass of the satellite; each of the two thrusters being oriented in such a way that the thrust axes of the two thrusters are parallel to one another and at right angles to the axis V.

Attitude and/or attitude rate of a vehicle may be controlled using jet paddles and/or movable masses. Thrust direction generally may also be controlled using jet paddles. The jet paddles may be moved into and/or sufficiently close to the exhaust flow, and out of the exhaust flow, to change the thrust direction. Movable masses may also be used in addition to, or in lieu of, jet paddles. Movement of the movable masses alters a center-of-mass of the vehicle, generating torque that changes vehicle attitude.

Methods and apparatus to methods and apparatus for performing propulsion operations using electric propulsion system are disclosed. An apparatus includes a space vehicle including means for performing propulsion operations without using a chemical propulsion system.

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.

A method for controlling the orbit of a satellite in earth orbit. The orbit of the satellite is controlled by commanding, according to a maneuver plan, a propulsion system having at least one thruster and a transporter to move the propulsion system. The maneuver plan includes at least two orbit-control maneuvers. The thrust powers of the propulsion system during the two orbit control maneuvers have respective thrust directions that are not parallel in an inertial frame of reference. Each thrust power is determined to simultaneously control the inclination and the position of the orbit of the satellite as well as to form a momentum that is suitable for unloading a device for storing angular momentum of the satellite in a plane orthogonal to the direction of thrust of the thrust power.

Methods and apparatus to methods and apparatus for performing propulsion operations using electric propulsion system are disclosed. An example method includes deploying a space vehicle including an electric propulsion system; and using the electric propulsion system for attitude control and orbit control, no other propulsion system provided to enable the attitude control and the orbit control.

Systems, apparatus, and method for momentum management for a spacecraft are disclosed. An example spacecraft includes a body; an appendage moveably coupled to the body; a thruster carried by the body; machine-readable instructions; and processor circuitry to execute the machine-readable instructions to detect a change in angular momentum at the spacecraft during firing of the thruster; and in response to the detection, cause the appendage to move relative to the body to adjust a center of mass of the spacecraft relative to a net thrust vector associated with the thruster.

An orbital maneuver apparatus includes a fluid supply arrangement, a main body, an actuation head, and a nozzle assembly. The main body includes an outer housing, an inner housing mounted in the outer housing such that the inner housing is arranged to rotate about a longitudinal direction of the main body, wherein the fluid supply tube extends in the inner housing of the main body and is stationary with respect to the outer housing. The actuation head is connected to the inner housing of the main body to rotate along with the inner housing. The nozzle assembly includes a first nozzle head and a second nozzle head which are in fluid communication with the fluid supply arrangement, and are both movably supported in the actuation cavity and are arranged to rotate correspondingly with the actuation head, and to further rotate about a transverse direction of the main body.