Abstract: Methods and apparatus to methods and apparatus for performing propulsion operations using electric propulsion system are disclosed. An example launch vehicle includes a first space vehicle including a first core structure and a first electric propulsion system, and a second space vehicle including a second core structure and a second electric propulsion system, the second core structure releasably attached to the first space vehicle in a stacked configuration.

Abstract: A space vehicle system, a method of manufacturing a multiple space vehicle system, and a method of disposing space vehicles into Earth orbit are disclosed. The space vehicle system may include a first space vehicle including a first core structure with a first wall thickness. The space vehicle system may include a second space vehicle including a second core structure with a second wall thickness, the second wall thickness different from the first wall thickness, and the second core structure releasably attached to the first space vehicle in a stacked configuration.

Abstract: A space vehicle system, a method of manufacturing a multiple space vehicle launch system, and a method to transmit a launch load between space vehicles during a launch are disclosed. The space vehicle system may include a first space vehicle including a first core structure, a second space vehicle including a second core structure releasably attached to the first space vehicle in a stacked configuration, a first solar array supported by the first core structure, the first core structure extending beyond a lower edge of the first solar array, and a second solar array supported by the second core structure, the second core structure extending beyond an upper edge of the second solar array.

Abstract: Methods and apparatus to methods and apparatus for performing propulsion operations using electric propulsion system are disclosed. An example launch vehicle includes a first space vehicle including a first core structure and a first electric propulsion system, and a second space vehicle including a second core structure and a second electric propulsion system, the second core structure releasably attached to the first space vehicle in a stacked configuration.

Abstract: Methods and apparatus to methods and apparatus for performing propulsion operations using electric propulsion system are disclosed. An example apparatus includes means to use an electric propulsion system coupled to a frame of a spacecraft, the electric propulsion system including at least a first thruster and a second thruster, the first thruster adjacent a first side of the frame, the second thruster adjacent a second side of the frame, and means to allow at least one of the first thruster or the second thruster to control the spacecraft without using a chemical propulsion system.

Abstract: 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.

Abstract: Methods and apparatus to methods and apparatus for performing propulsion operations using electric propulsion system are disclosed. An example apparatus includes means to use an electric propulsion system coupled to a frame of a spacecraft, the electric propulsion system including at least a first thruster and a second thruster, the first thruster adjacent a first side of the frame, the second thruster adjacent a second side of the frame, and means to allow at least one of the first thruster or the second thruster to control the spacecraft without using a chemical propulsion system.

Abstract: Apparatus and methods for controlling a spacecraft for a transfer orbit. The spacecraft includes a propulsion subsystem with electric thrusters that are installed with two-axis gimbal assemblies. The spacecraft also includes a controller that identifies a target spin axis for the spacecraft, determines an actual spin axis for the spacecraft during the transfer orbit, determines gimbal angles for the electric thruster(s) that adjust the actual spin axis toward the target spin axis, and initiates a burn of the electric thruster(s) at the gimbal angles.

Abstract: A space vehicle system, a method of manufacturing a multiple space vehicle launch system, and a method to transmit a launch load between space vehicles during a launch are disclosed. The space vehicle system may include a first space vehicle including a first core structure, a second space vehicle including a second core structure releasably attached to the first space vehicle in a stacked configuration, a first solar array supported by the first core structure, the first core structure extending beyond a lower edge of the first solar array, and a second solar array supported by the second core structure, the second core structure extending beyond an upper edge of the second solar array.

Abstract: 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.

Abstract: A space vehicle system, a method of manufacturing the space vehicle system, and a method of launching the space vehicle system are disclosed. The method of manufacturing the space vehicle system may include disposing a first space vehicle with an upper core structure upon a second space vehicle with a lower core structure such that loads of the first space vehicle are transmitted to the lower core structure of the second space vehicle.

Abstract: 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.

Abstract: 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.

Abstract: Apparatus and methods for controlling a spacecraft for a transfer orbit. The spacecraft includes a propulsion subsystem with electric thrusters that are installed with two-axis gimbal assemblies. The spacecraft also includes a controller that identifies a target spin axis for the spacecraft, determines an actual spin axis for the spacecraft during the transfer orbit, determines gimbal angles for the electric thruster(s) that adjust the actual spin axis toward the target spin axis, and initiates a burn of the electric thruster(s) at the gimbal angles.

Abstract: 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.

Abstract: A multiple space vehicle launch system that may be adapted to be disposed within a payload region of a launch vehicle fairing is disclosed. The vehicle launch system may include a first space vehicle including a first core structure and a second space vehicle including a second core structure. The second core structure may be oriented relative to the first space vehicle such that when placed within a fairing, a launch load is transmitted from the first core structure of the first space vehicle and is borne by the second core structure of the second space vehicle. The first space vehicle and the second space vehicle each include respective propulsion units.

Abstract: 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.

Abstract: A space vehicle system, a method of manufacturing the space vehicle system, and a method of launching the space vehicle system are disclosed. The method of manufacturing the space vehicle system may include disposing a first space vehicle with an upper core structure upon a second space vehicle with a lower core structure such that loads of the first space vehicle are transmitted to the lower core structure of the second space vehicle.

Abstract: A gridded ion propulsion system comprising two power controllers, four ion thrusters, and two switch assemblies. One switch assembly is connected to the two power controllers and to two of the four ion thrusters. The other switch assembly is connected to the two power controllers and to the other two ion thrusters. Each switch assembly has first and second switching states which can be selected to enable either power controller to supply power to any one of the four ion thrusters. Each switch assembly comprises a respective movable body and a respective multiplicity of switches which change state in unison when the movable body changes position. For example, the movable body may be a rotatable hollow shaft driven by a stepper motor.

Abstract: Methods and apparatus to methods and apparatus for performing propulsion operations using electric propulsion system are disclosed. An example apparatus includes a frame, a power source coupled to the frame and a payload coupled to the frame, the payload to receive or transmit data. The apparatus also includes an electric propulsion system coupled to the frame. The electric propulsion system is to enable attitude control, momentum control, and orbit control of the apparatus.