Combined electric thruster and method of operation

Abstract

The application discloses a combined electric thruster and a working method, which comprises a coaxial Hall module and a magnetic plasma module; the Hall module is located externally, and the magnetic plasma module is located internally; a magnet module is sleeved between the Hall module and the magnetic plasma module and is shared by the Hall module and the magnetic plasma module; the Hall module and the magnetic plasma module share an internal cathode, or the internal cathode is an electron source of the magnetic plasma module, and an external cathode is an electron source of the Hall module. The application combines the structures and magnetic field characteristics of the Hall thruster and the magnetic plasma thruster, places the magnetic plasma thruster at the central position of the Hall thruster, fully utilizes the central idle space of the super-power Hall thruster, shares part of structural components and magnetic fields, and comprehensively integrates the performance advantages of the super-power Hall thruster and the magnetic plasma thruster, so that the performance indexes of long service life, large thrust, high specific impulse and the like can be realized.

Description

Technical Field

[0001] This invention relates to the field of deep space exploration technology, specifically to a combined electric thruster and its operating method. Background Technology

[0002] Electric thrusters are one of the most widely used propulsion devices in aerospace. Based on their different operating principles, they are classified into several types, including Hall thrusters, ion thrusters, magneto-plasma thrusters, variable specific impulse thrusters, and magnetohydrodynamic thrusters. Each type of electric thruster has its own advantages and disadvantages. For example, ion thrusters have high specific impulse and strong stability, but their structure is relatively complex, making them suitable for aerospace missions with high specific impulse requirements. Hall thrusters have a simple structure and high reliability, with greater thrust than ion thrusters, but a smaller specific impulse, making them suitable for providing power for near-Earth satellite orbit control and attitude control. Magneto-plasma thrusters are small in size, have high thrust, and high energy density, but are generally suitable for operation under high-power conditions.

[0003] As the scope of deep space exploration missions continues to expand, traditional chemical propulsion methods not only require carrying large amounts of propellant but also consume significant flight time. For example, exploring the edge of the sun would take approximately 25 years, resulting in enormous time costs. While electric propulsion systems with high specific impulse, high thrust, and long lifespan can effectively shorten flight time and accelerate deep space exploration missions, current electric propulsion systems, under limited power conditions, cannot simultaneously meet the requirements of high specific impulse, high thrust, and long lifespan. Therefore, using combined thrusters, employed in combination at different stages of deep space missions, can leverage the advantages of different electric thrusters, greatly improving the efficiency of deep space exploration.

[0004] Ultra-high power (≥20kW) Hall thrusters typically have a specific impulse of 1500~2500s, offering advantages such as simple structure and high efficiency. With magnetically shielded magnetic field and structural design, their operational life can reach over 50,000 hours. However, due to their annular discharge channel and magnetic field design characteristics, ultra-high power Hall thrusters have a low effective utilization rate of their front-end area, resulting in inefficient use of space in the center and low thrust density. Magnetoplasma thrusters typically have a specific impulse of 3500s~6000s, suitable for ultra-high power operation (≥50kW). They offer advantages such as small size, high specific impulse, high power density, and high thrust density. However, due to their high plasma density, their structure is severely susceptible to ion erosion, limiting their operational life to only a few thousand hours. Due to space power limitations, Hall thrusters alone cannot meet the thrust requirements for rapid deep-space flight in deep space exploration, while magnetoplasma thrusters alone cannot meet the lifespan requirements for deep-space flight.

[0005] Compared with existing patents.

[0006] Publication number CN115059555A, entitled "A Pulse Detonation-Hall Hybrid Space Thruster," discloses a pulse detonation... The Hall effect hybrid space thruster and thrust control method include a pulse detonation thrust unit and a Hall effect thrust unit, which can operate in both pulse detonation and Hall effect thrust modes, combining the advantages of high thrust and high specific impulse of both. This patented design, combined with a Hall effect thruster, is a pulse detonation thruster. The combined thrusters cannot share a propellant system. Hall effect thrusters typically use inert gases or metal powders as propellants, while pulse detonation thrusters require a bicomponent propellant consisting of an oxidizer and a fuel, thus making the propellant supply system more complex.

[0007] The patent, with publication number CN108317061A and titled "An Ion Hall Hybrid Thruster with a Shared Magnet," discloses an ion Hall hybrid thruster with a shared magnet, comprising a ring-shaped ion thruster, a Hall thruster, a shared magnet, and a self-use magnet. The magnets are positioned according to the axial distance of the discharge channels of each thruster, which solves the problem of excessively large geometric dimensions in ion Hall hybrid thrusters. Compared to this invention, this patent integrates the Hall thruster and the ion thruster in a combined design, but the overall volume is still relatively large.

[0008] The patent, with publication number CN115559874A and titled "A Hybrid Propulsion Hall Thrust," discloses a hybrid propulsion Hall thruster that achieves two thrust output ranges—millinewton-level and newton-level—on a single thruster. The millinewton-level thrust is generated by the Hall thruster, while the newton-level thrust is generated by gas ejection from an intermediate Laval nozzle. Compared to the present invention, this patent integrates the Hall thruster with a cold gas propulsion method, resulting in a lower hybrid specific impulse. Summary of the Invention

[0009] The technical problem to be solved by this invention is that existing electric thrusters cannot adjust performance parameters over a wide range, and cannot balance thrust, specific impulse, and lifespan.

[0010] The present invention solves the above-mentioned technical problems through the following technical means: A combined electric thruster includes a coaxially designed Hall module and a magnetic plasma module; the Hall module is externally mounted, while the magnetic plasma module is internally mounted; a magnet module is nested between the Hall module and the magnetic plasma module and is shared by both; a built-in cathode is located at the center of the magnetic plasma module, and an external cathode is located outside the Hall module; the Hall module and the magnetic plasma module share the built-in cathode, or the built-in cathode serves as the electron source for the magnetic plasma module, and the external cathode serves as the electron source for the Hall module. This invention combines the structural and magnetic field characteristics of Hall thrusters and magnetic plasma thrusters, proposing a combined electric thruster design method. By placing the magnetic plasma thruster at the center of the Hall thruster, it fully utilizes the central empty space of the ultra-high-power Hall thruster, sharing some structural components, magnetic circuit components, cathodes, and magnetic fields. This integrates the performance advantages of ultra-high-power Hall thrusters and magnetic plasma thrusters, achieving performance indicators such as long lifespan, high thrust, and high specific impulse.

[0011] Furthermore, the magnetic plasma module includes an anode; the anode is internally cylindrical, forming a magnetic nozzle.

[0012] Furthermore, the nozzle of the built-in magnetic nozzle of the anode is gradually expanding.

[0013] Furthermore, the built-in cathode is located at the axial center of the magnetic plasma module and is insulated from the magnetic plasma module.

[0014] Furthermore, there are one or two external cathodes (backup), and the axis of the electron emission port is approximately parallel to the magnetic field lines of the external magnetic field.

[0015] Furthermore, the Hall module includes an inner magnetic pole, an outer magnetic pole, an inner magnetic screen, an outer magnetic screen, and a discharge channel; wherein the inner magnetic pole, the outer magnetic pole, the inner magnetic screen, and the outer magnetic screen constitute a Hall magnetic circuit, guiding the magnetic field generated by the magnet module to form a focused magnetic field within the discharge channel.

[0016] Furthermore, the discharge channel is an annular open channel.

[0017] Furthermore, the bottoms of the Hall module and the magnetic plasma module are fixed to the base plate, and the Hall module and the magnetic plasma module have no radial contact.

[0018] Furthermore, it also includes a refrigeration device; the heat-conducting surface of the refrigeration device is connected to the bottom of the Hall module and the magnetic plasma module.

[0019] The present invention also provides a method for operating a combined electric thruster, applied to the aforementioned combined electric thruster, characterized in that it includes the following three operating modes: Operating mode: Low thrust and long lifespan operating mode. In this mode, the Hall module works independently with a lifespan of over 10,000 hours. It generates relatively small thrust, which is suitable for low thrust and long-term orbital acceleration processes in deep space exploration. Operating mode: High thrust and high specific impulse operating mode. In this mode, the magnetoplasm module works alone and generates a large thrust, but its independent operating life is short, about several thousand hours. It is suitable for high thrust orbital transfer operations in deep space exploration. Operating mode: Hybrid operating mode. In this mode, the Hall module and the magnetoplasm module work simultaneously, generating greater thrust, but requiring greater electrical power. It is suitable for high-power operation in deep space exploration.

[0020] The advantages of this invention are: This invention combines the structural and magnetic field characteristics of Hall thrusters and magnetoplasm thrusters to propose a combined electric thruster design method. The magnetoplasm thruster is placed at the center of the Hall thruster, making full use of the central empty space of the ultra-high power Hall thruster. It shares some structural components, magnetic circuit components, cathodes and magnetic fields, and integrates the performance advantages of ultra-high power Hall thrusters and magnetoplasm thrusters, achieving performance indicators such as long life, high thrust and high specific impulse.

[0021] This invention integrates a Hall thruster and a magnetoplasm thruster in a hybrid design, sharing the same magnetic field. This results in high power density, small size, and high thrust performance for the same power output. It can operate in conjunction with or independently, and supports multiple operating modes. This combined thruster leverages the advantages of both Hall and magnetoplasm thrusters to achieve a compact size, high thrust density, high power density, high thrust, high specific impulse, and long lifespan, making it suitable for long-distance, long-duration space missions such as deep space exploration. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the magnetic field configuration of the combined thruster in an embodiment of the present invention; Figure 2 This is a schematic diagram of the overall structure of the combined thruster in an embodiment of the present invention; Figure 3 This is a cross-sectional schematic diagram of the combined thruster described in this embodiment of the invention. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] Example 1 This embodiment describes a combined electric thruster, such as... Figure 1 , Figure 2 As shown, it mainly includes a magnetic plasma module 1, a magnet module 2, a Hall module 3, and a cathode module 4. The cathode module 4 includes a built-in cathode 4-1 and an external cathode 4-2. The magnetic plasma module 1 is located inside the Hall module 3. Figure 3 As shown, the main body structure of the combined electric thruster is centrally rotationally symmetrical, and from the inside out are the built-in cathode 4-1, magnetic plasma module 1, magnet module 2, Hall module 3, and external cathode 4-2.

[0025] In this embodiment, the magnetic plasma module 1 mainly consists of an anode 1-1 and a gas distributor (not shown in the figure). The anode 1-1 is a barrel-shaped structure with an open top; the built-in cathode 4-1 is located at the center of the bottom of the anode 1-1. The magnet module 2 is a cylindrical structure that is fitted outside the anode 1-1. The anode 1-1 is designed to match the position of the magnet module 2, forming a "magnetic nozzle" configuration inside the anode 1-1 to confine the high-density plasma beam and accelerate its ejection. Furthermore, the anode 1-1 adopts a "gradually expanding nozzle" configuration to reduce the erosion of the anode by the plasma beam.

[0026] In this embodiment, the magnet module 2 is mainly composed of a strong excitation coil or a permanent magnet. It can be made of superconducting materials and adopt a superconducting excitation scheme. It can also be used with a Stirling refrigerator to create a superconducting low temperature state of the magnet, thereby saving excitation power consumption.

[0027] The Hall module 3 mainly consists of an inner magnetic pole 3-1, an outer magnetic pole 3-2, an inner magnetic screen 3-3, an outer magnetic screen 3-4, and a discharge channel 3-5. The inner magnetic pole 3-1, outer magnetic pole 3-2, inner magnetic screen 3-3, and outer magnetic screen 3-4 form a Hall magnetic circuit, which guides the magnetic field generated by the magnet module 2 to form a focused magnetic field in the discharge channel 3-5, thereby improving the plasma beam efficiency. At the same time, the morphology of the discharge channel 3-5 is matched and designed. The discharge channel 3-5 is an open annular channel, and a magnetic shielding magnetic field configuration is formed near the outlet of the discharge channel 3-5 to reduce plasma erosion of the wall surface and significantly extend the working life.

[0028] The built-in cathode 4-1 and the external cathode 4-2 are generally hollow cathodes, serving as the electron source. For example... Figure 1 As shown, the built-in cathode 4-1 is placed at the central axis of the combined electric thruster and is insulated from the magnetic plasma module 1. Figure 1 As shown, the external cathode 4-1 is placed outside the combined electric thruster and is insulated from the combined electric thruster by a bracket, and the axis of the electron emission port is approximately parallel to the magnetic field lines of the external magnetic field.

[0029] The combined thruster is externally connected to a cooling system at its bottom, which can be a Stirling refrigerator. The bottom of the thruster directly contacts the heat pipes or heat-conducting plates of the cooling system to transfer heat away. This serves two purposes: firstly, it creates a low-temperature superconducting environment for the superconducting excitation coil; secondly, it removes the heat generated by the magnetic plasma module 1, preventing heat accumulation that could affect the thruster's thermal stability. The Hall module 3 and the magnetic plasma module 1 are designed with thermal insulation. They are only connected to the mounting base plate and there is no contact between them in the radial direction. At the same time, a low-emissivity coating is added to the radiating surface between the two to reduce the amount of heat radiation between the two modules and prevent the high-density heat flow of the magnetic plasma module 1 from being conducted to the Hall module 3 during operation, thus compromising the thermal stability of the Hall module 3. The external cathode 4-2 serves as the electron source for the Hall module 3. A dual-cathode configuration can be used to improve the working life of the Hall module 3.

[0030] In this embodiment, the magnet module 2 generates a strong magnetic field in space, forming a magnetic field of intensity on the order of kilogauss within the magnetic plasma module 1 (the strongest magnetic field along the axial line of the discharge channel). Then, by utilizing the magnetic saturation characteristics of the inner magnetic pole 3-1, outer magnetic pole 3-2, inner magnetic screen 3-3, and outer magnetic screen 3-4 of the magnetic circuit component in the Hall module 3, a magnetic field of intensity on the order of hundreds of gauss is achieved within the discharge channel 3-5 of the Hall module 3 (the strongest magnetic field along the axial line of the discharge channel), thus meeting the operational needs of the two modules.

[0031] Example 2 The thruster based on Embodiment 1 has at least the following three operating modes: Operating mode 1: Low thrust and long lifespan operating mode. In this mode, Hall module 3 works alone and has a working lifespan of over 40,000 hours. It generates relatively small thrust and is suitable for long-term orbital acceleration processes with small thrust in deep space exploration. Working mode 2: High thrust and high specific impulse working mode. In this mode, the magnetic plasma module 1 works alone and generates a large thrust, but the lifespan of working alone is short. It is suitable for high thrust orbital transfer working process in deep space exploration. Operating mode 3: Hybrid operating mode. In this mode, Hall module 3 and magnetic plasma module 1 work simultaneously, generating greater thrust, but requiring greater electrical power. It is suitable for working in high-power mode during deep space exploration.

[0032] The combined thruster in this embodiment can operate in three different modes, combining the advantages of high specific impulse and high thrust density of magnetic plasma and high specific impulse and long life of Hall thruster respectively. In different operating modes, the Hall module 3 and the magnetic plasma module 1 can freely adjust their operating power according to the power supplied by the electrical energy, making the thruster's performance coverage wider and its adaptability stronger.

[0033] In this embodiment, both the Hall module 3 and the magnetic plasma module 1 can have their input parameters adjusted independently to adapt to a wide range of discharge voltage and anode flow rate adjustments. The Hall module 3 and the magnetic plasma module 1 can use the same propellant supply circuit and the same propellant, such as xenon, krypton, argon, iodine, or other commonly used electric propulsion propellants. Flow controllers are used at the thruster interface to control the flow rate and on / off state. Alternatively, depending on requirements, two propellant supply circuits can be used, employing different types of propellants.

[0034] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A combined electric thruster, characterized in that, The system includes a Hall module (3) and a magnetic plasma module (1) designed coaxially. The Hall module (3) is located externally, and the magnetic plasma module (1) is located internally. A magnet module (2) is sleeved between the Hall module (3) and the magnetic plasma module (1) and is shared by the Hall module (3) and the magnetic plasma module (1). An internal cathode (4-1) is provided at the center of the magnetic plasma module (1), and an external cathode (4-2) is provided externally to the Hall module (3). The internal cathode (4-1) is the electron source of the magnetic plasma module (1), and the external cathode (4-2) is the electron source of the Hall module (3). The magnet module (2) generates a strong magnetic field in space and forms a magnetic field with a strength of thousands of Gausss inside the magnetic plasma module (1). By utilizing the magnetic saturation characteristics of the Hall magnetic circuit formed by the inner magnetic pole (3-1), the outer magnetic pole (3-2), the inner magnetic screen (3-3), and the outer magnetic screen (3-4), a magnetic field with a strength of hundreds of Gausss is formed in the discharge channel of the Hall module (3).

2. The combined electric thruster according to claim 1, characterized in that, The magnetic plasma module (1) includes an anode (1-1); the anode (1-1) is internally cylindrical to form a magnetic nozzle.

3. A combined electric thruster according to claim 2, characterized in that, The nozzle of the magnetic nozzle built into the anode (1-1) is gradually expanding.

4. A combined electric thruster according to any one of claims 1 to 3, characterized in that, The built-in cathode (4-1) is located at the axial position of the magnetic plasma module (1) and is insulated from the magnetic plasma module (1).

5. A combined electric thruster according to any one of claims 1 to 3, characterized in that, There are 1 to 2 external cathodes (4-2), and the axis of the electron emission port is approximately parallel to the magnetic field lines of the external magnetic field.

6. A combined electric thruster according to any one of claims 1 to 3, characterized in that, The Hall module (3) also includes a discharge channel (3-5); wherein the inner magnetic pole (3-1), the outer magnetic pole (3-2), the inner magnetic screen (3-3), and the outer magnetic screen (3-4) constitute a Hall magnetic circuit, which guides the magnetic field generated by the magnet module (2) to form a focused magnetic field in the discharge channel (3-5).

7. A combined electric thruster according to claim 6, characterized in that, The discharge channel (3-5) is an annular open channel.

8. A combined electric thruster according to any one of claims 1 to 3, characterized in that, The bottoms of the Hall module (3) and the magnetic plasma module (1) are fixed to the base plate, and the Hall module (3) and the magnetic plasma module (1) have no radial contact.

9. A combined electric thruster according to any one of claims 1 to 3, characterized in that, It also includes a refrigeration device; the heat-conducting surface of the refrigeration device is connected to the bottom of the Hall module (3) and the magnetic plasma module (1).

10. A method for operating a combined electric thruster, applied to the combined electric thruster according to any one of claims 1 to 9, characterized in that, The following three operating modes are included: Working mode 1: Low thrust long life working mode. In this state, the Hall module (3) works alone and generates a small thrust, which is suitable for the small thrust long-term orbit acceleration process in deep space exploration. Working mode 2: High thrust and high specific impulse working mode. In this state, the magnetic plasma module (1) works alone, which is suitable for the high thrust orbital transfer process in deep space exploration. Working mode 3: Hybrid working mode. In this mode, the Hall module (3) and the magnetic plasma module (1) work simultaneously, which is suitable for working in high power mode during deep space exploration.

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