Abstract: Described herein is a thrust system for a vehicle that includes at least three electrical power controllers, at least four electrical switches each configured to receive electrical power from at least one of the at least three electrical power controllers, and at least three thrusters each configured to receive electrical power from at least one of the at least three electrical switches. The at least four electrical switches are operable to switch a supply of electrical power from any of the at least three electrical power controllers to any one of the at least three thrusters.

Abstract: Described herein is a thrust system for a vehicle that includes at least three electrical power controllers, at least four electrical switches each configured to receive electrical power from at least one of the at least three electrical power controllers, and at least three thrusters each configured to receive electrical power from at least one of the at least three electrical switches. The at least four electrical switches are operable to switch a supply of electrical power from any of the at least three electrical power controllers to any one of the at least three thrusters.

Abstract: Described herein is a thrust system for a vehicle that includes at least three electrical power controllers, at least four electrical switches each configured to receive electrical power from at least one of the at least three electrical power controllers, and at least three thrusters each configured to receive electrical power from at least one of the at least three electrical switches. The at least four electrical switches are operable to switch a supply of electrical power from any of the at least three electrical power controllers to any one of the at least three thrusters.

Abstract: Described herein is a thrust system for a vehicle that includes at least three electrical power controllers, at least four electrical switches each configured to receive electrical power from at least one of the at least three electrical power controllers, and at least three thrusters each configured to receive electrical power from at least one of the at least three electrical switches. The at least four electrical switches are operable to switch a supply of electrical power from any of the at least three electrical power controllers to any one of the at least three thrusters.

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: An electric thruster has at least a portion of a surface of at least one of the component elements of its housing surface treated to increase the thermal transmission at the surface. The surface treatment is selected to increase the thermal absorption and thence the absorption of heat at the interiorly facing surfaces of the treated component, and/or to increase the thermal emissivity and thence radiation heat loss at the exteriorly facing surfaces of the treated component, and/or to increase the effective surface area through which heat is absorbed or emitted. The surface-treated housing components are assembled together with a cathode assembly, an ionization chamber, a propellant gas source, and a magnetic structure to form an electric thruster.

Abstract: An electric thruster has at least a portion of a surface of at least one of the component elements of its housing surface treated to increase the thermal transmission at the surface. The surface treatment is selected to increase the thermal absorption and thence the absorption of heat at the interiorly facing surfaces of the treated component, and/or to increase the thermal emissivity and thence radiation heat loss at the exteriorly facing surfaces of the treated component, and/or to increase the effective surface area through which heat is absorbed or emitted. The surface-treated housing components are assembled together with a cathode assembly, an ionization chamber, a propellant gas source, and a magnetic structure to form an electric thruster.

Abstract: A rocket engine has a combustion chamber, an injector, and an attachment between the combustion chamber and the injector. The attachment includes an annular metallic deposit joined to the chamber wall outer surface, and an annular transition ring structure. The transition ring structure has an annular step collar, and an annular adaptor ring brazed to the annular step collar. The adaptor ring is welded on one end to the injector and on the other end to the metallic deposit.

Abstract: A rocket engine includes a generally cylindrical annular combustion chamber, an injector attached to an injector end of the combustion chamber, a generally cylindrical annular step collar fitting within the combustion chamber at the injector end thereof, and an attachment of the combustion chamber, the injector, and the step collar. The maximum outer diameter of the step collar is from about 0.020 inches to about 0.024 inches smaller than the inner diameter of the combustion chamber, and has a length of from about 21 to about 31 percent of the length of the combustion chamber. The step collar is made of a material having a melting point greater than that of the combustion chamber. The attachment preferably includes a clip structure joining the combustion chamber and the step collar.

Abstract: A rocket engine is fabricated by a multistep brazing and welding technique. An annular step collar is fns brazed to a trnnsition joint. This first subassembly is second brazed to the combustion chamber. This second subassembly is third brezed to an annular adaptor to form a third subassembly. The succeeding brazing steps are performed at successively lower temperatures. The third subassembly is welded to an injector.

Abstract: An ion thruster has a source of a plasma, and an ion-optics system located in sufficient proximity to the source of the plasma to extract ions therefrom. The ion-optics system includes at least two grids arranged in a facing-but-spaced-apart relationship to each other, with each grid being axisymmetric about a grid axis. Each grid includes a peripheral region defining a grid plane perpendicular to the grid axis, a first region of curvature adjacent to the peripheral region, and a second region of curvature along the grid axis such that the first region of curvature lies between the second region of curvature and the peripheral region. The first region of curvature is a convexly curved segment of a first sphere relative to the grid plane, and the second region of curvature is a concavely curved segment of a second sphere relative to the grid plane.