Steerable hall effect thruster having plural independently controllable propellant injectors and a frustoconical exhaust outlet

1. A steerable-thrust Hall effect thruster comprising:

an annular channel defined by two concentric walls with a central axis, the annular channel including an open end and a closed end, and including an upstream segment beside the closed end that is subdivided by radial walls into a plurality of separate compartments;

an anode situated at the closed end of the annular channel;

an injection circuit for injecting propulsion gas into the separate compartments of the annular channel, the injection circuit including at least one individual flow rate regulator device for each separate compartment;

a magnetic circuit for generating a magnetic field at the open end of the annular channel and including at least a final stage with an inner pole and a facing outer pole, wherein the inner pole is offset axially downstream relative to the outer pole, so that the magnetic field is inclined relative to a transverse plane of the thruster; and

a cathode downstream from the open end of the annular channel.

2. The steerable-thrust Hall effect thruster according to claim 1 , wherein the annular channel includes a downstream segment beside the open end with a meridian plane that diverges in a downstream direction.

3. The steerable-thrust Hall effect thruster according to claim 1 , wherein the annular channel is not axisymmetric.

4. The steerable-thrust Hall effect thruster according to claim 3 , wherein the annular channel presents a cross-section with a main axis of symmetry and a secondary axis of symmetry that is perpendicular to and shorter than the main axis of symmetry.

5. The steerable-thrust Hall effect thruster according to claim 1 , wherein the at least one individual flow rate regulator device is connected to a control unit.

6. The steerable-thrust Hall effect thruster according to claim 1 , wherein the concentric walls are made of ceramic material.

7. The steerable-thrust Hall effect thruster according to claim 2 , wherein the magnetic field is substantially perpendicular to the meridian plane.

8. The steerable-thrust Hall effect thruster according to claim 2 , wherein the concentric walls of the annular channel in the downstream segment are inclined outwards, and the meridian plane is defined therebetween.

9. A space vehicle incorporating at least one steerable-thrust Hall effect thruster for controlling attitude and/or trajectory of the space vehicle, wherein the at least one steerable-thrust Hall effect thruster comprises:

an annular channel defined by two concentric walls with a central axis, the annular channel including an open end and a closed end, and including an upstream segment beside the closed end that is subdivided by radial walls into a plurality of separate compartments;

an anode situated at the closed end of the annular channel;

an injection circuit for injecting propulsion gas into the separate compartments of the annular channel, the injection circuit including at least one individual flow rate regulator device for each separate compartment;

a magnetic circuit for generating a magnetic field at the open end of the annular channel and including at least a final stage with an inner pole and a facing outer pole, wherein the inner pole is offset axially downstream relative to the outer pole, so that the magnetic field is inclined relative to a transverse plane of the thruster; and

a cathode downstream from the open end of the annular channel.

10. A method of generating steerable thrust by a Hall effect thruster, the method comprising:

emitting electrons from a cathode situated downstream from an open end of an annular channel defined by two concentric walls with a central axis;

generating a radial magnetic field by a magnetic circuit at the open end of the annular channel to trap the electrons emitted by the cathode, thereby generating an electric field between the open end and an anode situated at a closed end of the annular channel;

injecting a propulsion gas via an injection circuit into an upstream segment of the annular channel that is subdivided into a plurality of separate compartments by radial walls, each separate compartment receiving a flow of gas that is individually regulated by at least one regulator device;

ionizing the propulsion gas by electrons escaping from the magnetic field towards the anode; accelerating the ionized propulsion gas by the electric field axially towards the open end of the annular channel; and

deflecting the propulsion gas, which has been ionized by the ionizing, radially outwards by a virtual cathode grid that is inclined relative to a transverse plane of the thruster and that is formed by electrons trapped by a final stage of the magnetic circuit including an inner pole and a facing outer pole with the inner pole being axially offset downstream relative to the outer pole.

11. The method of generating steerable thrust according to claim 10 , wherein at least one regulator device is controlled by a control unit.

12. The method of generating steerable thrust according to claim 10 , wherein modulus and/or orientation of the thrust are controlled to control trajectory and/or attitude of a space vehicle incorporating the Hall effect thruster.