Multi-air-supply system based on Kaufman electric thruster

Abstract

The invention relates to the technical field of spacecraft propulsion, in particular to a multi-gas-supply system based on a Kaufman electric thruster, which comprises a passive gas inlet device, a turbo molecular pump, an electric thruster, a microwave power supply, a microwave neutralizer, a microwave cathode assembly, a gas cylinder and a controller, and is characterized in that the output end of the passive gas inlet device is connected with the turbo molecular pump; the turbo molecular pump is connected with the electric thruster through a main air inlet pipeline; the electric thruster is an electric thruster of a Kaufman structure and comprises a discharge chamber and a microwave cathode assembly. The microwave power supply is respectively connected with the microwave cathode assembly and the microwave neutralizer; the gas cylinder is connected with the main gas inlet pipeline through a flow meter and a second pipeline; and the controller is respectively connected with the turbo molecular pump and the flow meter. According to the invention, based on the Kaufman type electric thruster, a multi-gas supply mode is adopted for gas supply, so that the spacecraft can reside in the ultralow earth orbit for a long time under the condition that the environment gas condition has certain amplitude fluctuation.

Description

Technical Field

[0001] This application relates to the field of spacecraft propulsion technology, and more specifically, to a multi-gas supply system based on a Kaufman electric thruster. Background Technology

[0002] Air-breathing electric propulsion systems use solar cells for energy and utilize the rarefied nitrogen, oxygen, and oxygen atoms in the ultra-low Earth orbit environment as the working fluid source. The ionization and accelerated ejection of these gases generate thrust, which serves as the power source for maintaining the orbit of ultra-low Earth orbit spacecraft. This allows spacecraft to stay and maneuver in ultra-low Earth orbit with less or no working fluid, solving the problem that existing technologies cannot enable spacecraft to stay and maneuver in ultra-low Earth orbit for extended periods. It is widely used in spacecraft platforms such as high-resolution Earth observation satellites, Earth gravity field measurement satellites, and ultra-high-speed communication satellites.

[0003] When spacecraft operate in very low Earth orbit, the energy and working fluid available for air-breathing electric propulsion systems are significantly limited. Therefore, high efficiency is required for the electric thrusters. However, compared to traditional Xe propellants, ambient gas propellants have higher first ionization energies and smaller ionization cross-sections. Furthermore, the fragmentation, rotation, and vibration of diatomic molecules contribute to lower thruster efficiency compared to Xe propellant-based systems. Therefore, improving thruster efficiency is the most crucial factor determining the feasibility of air-breathing electric propulsion technology. Among relatively mature electric thruster types, Kaufman thrusters are significantly more efficient than microwave, radio frequency, and Hall thrusters.

[0004] Traditional Kaufman electric thrusters use hollow cathodes as both the main cathode and neutralizer cathode. Operating in an oxygen-containing gas environment (the main gas components in ultra-low Earth orbit are N2, O2, and AO), the emitter of the hollow cathode becomes poisoned, leading to a reduced lifespan. Microwave (radio frequency) cathodes avoid this problem, significantly increasing the lifespan of air-breathing electric propulsion systems. However, the ambient gas density in ultra-low Earth orbit fluctuates, requiring adjustments to stabilize the input mass flow rate of the electric thruster. This primarily involves increasing the speed of the turbomolecular pump to maintain a relatively stable working propellant mass flow rate when the orbital ambient gas density decreases. Fluctuations in ambient gas density can lead to an increase in spacecraft damping force. During events such as geomagnetic storms, the ambient gas density in the spacecraft's orbit can increase dramatically, causing a sharp rise in drag. In both of these scenarios, using ambient gas as the working fluid alone is insufficient to achieve thrust-drag balance. Therefore, it is necessary to use Xe working fluid or a mixture of ambient gas and Xe working fluid to improve electric thrust efficiency and achieve thrust-drag balance. Summary of the Invention

[0005] This application provides a multi-gas supply system based on a Kaufman electric thruster, which can adapt to changes in ambient gas density fluctuations, provide power for ultra-low Earth orbit spacecraft, and achieve thrust-drag balance for spacecraft in ultra-low Earth orbit.

[0006] To achieve the above objectives, this application provides a multi-gas supply system based on a Kaufman electric thruster, including a passive air intake device, a turbomolecular pump, an electric thruster, a microwave power supply, a microwave neutralizer, a microwave cathode assembly, a gas cylinder, and a controller. The passive air intake device collects and compresses ambient gas, and its output is connected to the turbomolecular pump. The turbomolecular pump is connected to the electric thruster via a main air intake pipeline. The electric thruster is a Kaufman-configured electric thruster, including a discharge chamber and a microwave cathode assembly. The microwave power supply is located outside the electric thruster and is connected to both the microwave cathode assembly and the microwave neutralizer. The microwave neutralizer is located at the outlet of the electric thruster and is connected to the main air intake pipeline via a first pipeline. The gas cylinder is connected to the main air intake pipeline via a flow meter and a second pipeline. The controller is connected to both the turbomolecular pump and the flow meter. The interior of the discharge chamber is connected to the main air intake pipeline via a third and a fourth pipeline. The interior of the microwave cathode assembly is connected to the main air intake pipeline via a fifth and a sixth pipeline.

[0007] Furthermore, a shielding grid and an acceleration grid are installed at the outlet end of the discharge chamber; a thruster permanent magnet is installed on the outer wall of the discharge chamber.

[0008] Furthermore, the microwave cathode assembly is located at the entrance end of the discharge chamber and includes a front magnetic yoke, a reinforcing plate, a microwave antenna, an electron extraction plate, a microwave cathode permanent magnet, a microwave connector, and a rear magnetic yoke. Specifically: the front magnetic yoke is located at the front end of the plasma generation region; the reinforcing plate is located in front of the front magnetic yoke and connected to the microwave cathode housing; the microwave antenna is located inside the discharge chamber of the microwave cathode; the electron extraction plate is located between the front magnetic yoke and the reinforcing plate; the microwave cathode permanent magnet surrounds the discharge region of the microwave antenna; the rear magnetic yoke is located at the rear end of the plasma generation region; and the microwave connector is connected to both the microwave antenna and the microwave power supply.

[0009] Furthermore, a first valve is installed on the main intake pipe; a second valve is installed on the first pipe; a third valve is installed on the third pipe; and a fourth valve is installed on the fourth pipe.

[0010] Furthermore, it also includes a mass spectrometer, which is installed at the input of the passive air intake device and connected to the controller.

[0011] Furthermore, a vacuum gauge and a thermometer are installed at the connection between the output end of the passive air intake device and the turbomolecular pump, and the vacuum gauge is connected to the controller.

[0012] Furthermore, the gas inside the cylinder is xenon.

[0013] Furthermore, the speed of the turbomolecular pump can be adjusted by a controller based on the density of the ambient gas.

[0014] This application provides a multi-air supply system based on a Kaufman electric thruster, which has the following advantages: This application utilizes a Kaufman-type electric thruster with multiple gas supply modes, enabling the spacecraft to remain in ultra-low Earth orbit for extended periods even under fluctuating environmental gas conditions. The electric thruster employs a microwave cathode structure, avoiding the lifespan shortening caused by oxygen poisoning in a hollow cathode environment. A mass spectrometer can measure the composition and concentration of the orbital environment for spacecraft equipped with an air-breathing electric propulsion system; a vacuum gauge and thermometer can measure the gas pressure and temperature at the turbomolecular pump inlet. Combining the gas composition and concentration, the mass flow rate of the working fluid output from the turbomolecular pump (i.e., the input to the electric thruster) can be calculated, achieving thrust-drag balance for the spacecraft in ultra-low Earth orbit. Attached Figure Description

[0015] The accompanying drawings, which form part of this application, are used to provide a further understanding of the application and to make other features, objects, and advantages of the application more apparent. The illustrative embodiments and descriptions of this application are used to explain the application and do not constitute an undue limitation of the application. In the drawings: Figure 1 This is a schematic diagram of a multi-air supply system based on a Kaufman electric thruster provided according to an embodiment of this application; In the diagram: 1-Passive intake device, 2-Turbomolecular pump, 3-Electric thruster, 4-Microwave power supply, 5-Microwave neutralizer, 6-Gas cylinder, 7-Controller, 8-Discharge chamber, 9-Main intake pipeline, 10-First pipeline, 11-Flow rate, 12-Second pipeline, 13-Third pipeline, 14-Fourth pipeline, 15-Fifth pipeline, 16-Sixth pipeline, 17-Shielding grid, 18-Accelerating grid, 19-Thruster permanent magnet, 20-Front yoke, 21-Reinforcing plate, 22-Microwave antenna, 23-Electron lead-out plate, 24-Microwave cathode permanent magnet, 25-Microwave connector, 26-Rear yoke, 27-First valve, 28-Second valve, 29-Third valve, 30-Fourth valve, 31-Mass spectrometer, 32-Vacuum gauge, 33-Thermometer. Detailed Implementation

[0016] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0017] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this application described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0018] In this application, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," and "longitudinal" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing this application and its embodiments, and are not intended to limit the indicated device, element, or component to having a specific orientation, or to be constructed and operated in a specific orientation.

[0019] Furthermore, in addition to indicating location or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in some cases to indicate a certain dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0020] In addition, the term "multiple" should mean two or more.

[0021] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0022] like Figure 1As shown, this application provides a multi-gas supply system based on a Kaufman electric thruster, including a passive air intake device 1, a turbomolecular pump 2, an electric thruster 3, a microwave power supply 4, a microwave neutralizer 5, a microwave cathode assembly, a gas cylinder 6, and a controller 7. The passive air intake device 1 is used to collect and compress ambient gas, and its output is connected to the turbomolecular pump 2. The turbomolecular pump 2 is connected to the electric thruster 3 through a main air intake pipe 9. The electric thruster 3 is a Kaufman-configured electric thruster, including a discharge chamber 8 and a microwave cathode assembly. The microwave power supply 4 is located in... The electric thruster 3 is externally connected to the microwave cathode assembly and the microwave neutralizer 5, respectively. The microwave neutralizer 5 is located at the outlet end of the electric thruster 3 and is connected to the main air intake line 9 through the first pipeline 10. The gas cylinder 6 is connected to the main air intake line 9 through the flow meter 11 and the second pipeline 12. The controller 7 is connected to the turbomolecular pump 2 and the flow meter 11, respectively. The discharge chamber 8 is internally connected to the main air intake line 9 through the third pipeline 13 and the fourth pipeline 14. The microwave cathode assembly is internally connected to the main air intake line 9 through the fifth pipeline 15 and the sixth pipeline 16.

[0023] Specifically, the multi-gas supply system based on Kaufman electric thrusters provided in this application embodiment adopts Kaufman-type electric thrusters 3. Compared with microwave, radio frequency, Hall thruster and other types of electric thrusters, it can significantly improve the efficiency of electric thrusters 3. At the same time, it supplies gas to electric thrusters 3 through multiple gas supply pipelines, which can adapt to changes in ambient gas density fluctuations and achieve thrust-resistance balance of spacecraft in ultra-low Earth orbit. This allows spacecraft to stay in ultra-low Earth orbit for a long time under conditions where ambient gas conditions fluctuate to a certain extent, making full use of ultra-low Earth orbit resources. The passive intake device 1 is used to collect and compress ambient gas; the turbomolecular pump 2 is used to further pressurize and deliver the gas to the electric thruster 3; the electric thruster 3 preferably adopts a Kaufman configuration electric thruster, which is composed of a discharge chamber 8 and a microwave cathode assembly; the microwave power supply 4 generates microwave power on the one hand, converting DC power into microwave electromagnetic energy of a specific frequency and power, and on the other hand, performs energy coupling, transmitting and coupling microwave energy efficiently and with low loss to the microwave cathode assembly and microwave neutralizer 5; the microwave neutralizer 5 is used to inject electrons into the high-speed positive ion beam ejected by the electric thruster 3 to achieve macroscopic electroneutrality of the beam; the gas cylinder 6 is used to supply Xe gas to the system; the controller 7 adjusts the speed of the turbomolecular pump 2 and / or the gas supply ratio of the Xe gas cylinder 6 according to the gas parameters to maintain a stable input mass flow rate of the electric thruster 3.

[0024] Furthermore, a shielding grid 17 and an accelerating grid 18 are provided at the outlet end of the discharge chamber 8; a thruster permanent magnet 19 is provided on the outer wall of the discharge chamber 8. The shielding grid 17 is used to shield the discharge chamber 8 from interference from the accelerating electric field and maintain discharge stability; the accelerating grid 18 and the shielding grid 17 form a strong electric field, which accelerates the ions and generates thrust. The thruster permanent magnet 19 is arranged circumferentially or axially along the side wall of the thruster, located around the discharge chamber 8, and generates a radial or axial magnetic field to constrain electron movement, enhance ionization efficiency, increase plasma density, and improve thruster performance.

[0025] Furthermore, the microwave cathode assembly is located at the entrance end of the discharge chamber 8, including a front magnetic yoke 20, a reinforcing plate 21, a microwave antenna 22, an electron extraction plate 23, a microwave cathode permanent magnet 24, a microwave connector 25, and a rear magnetic yoke 26. Specifically: the front magnetic yoke 20 is located at the front end of the plasma generation region; the reinforcing plate 21 is located in front of the front magnetic yoke 20 and connected to the shell of the microwave cathode; the microwave antenna 22 is located inside the discharge chamber of the microwave cathode; the electron extraction plate 23 is located between the front magnetic yoke 20 and the reinforcing plate 21; the microwave cathode permanent magnet 24 is arranged around the discharge region of the microwave antenna 22; the rear magnetic yoke 26 is located at the rear end of the plasma generation region; and the microwave connector 25 is connected to both the microwave antenna 22 and the microwave power supply 4.

[0026] Specifically, in the microwave cathode assembly of this application, the front yoke 20 and the microwave cathode permanent magnet 24 form a magnetic circuit, guiding and concentrating the magnetic field, enhancing the electron cyclotron resonance effect, and improving ionization efficiency. The reinforcing plate 21 is used to enhance structural rigidity and prevent deformation under vibration or thermal load. The microwave antenna 22 is connected to the microwave power supply 4, coupling microwave energy into the gas and exciting gas ionization. The electron extraction plate 23 mainly controls the extraction of electrons from the cathode plasma to the main discharge chamber 8, and can adjust the electron flux density, affecting discharge stability. The rear yoke 26 closes the magnetic field lines, improving magnetic field utilization efficiency and reducing leakage flux. The microwave cathode permanent magnet 24, the front yoke 20, and the rear yoke 26 form a closed magnetic circuit, generating the static magnetic field required for electron cyclotron resonance, significantly improving microwave energy absorption and ionization efficiency. The microwave connector 25 connects the microwave antenna 22 and the microwave power supply 4, transmitting microwave power and ensuring impedance matching and low-loss transmission.

[0027] Furthermore, a first valve 27 is installed on the main intake pipe 9; a second valve 28 is installed on the first pipe 10; a third valve 29 is installed on the third pipe 13; and a fourth valve 30 is installed on the fourth pipe 14. The valves control the flow of gas within each gas pipe according to the actual intake conditions.

[0028] Furthermore, it also includes a mass spectrometer 31, which is installed at the input end of the passive air intake device 1 and connected to the controller 7. The mass spectrometer 31 can measure the composition and content of the gas in the orbital environment.

[0029] Furthermore, a vacuum gauge 32 and a thermometer 33 are installed at the connection between the output end of the passive air intake device 1 and the turbomolecular pump 2. The vacuum gauge 32 is connected to the controller 7. The vacuum gauge 32 can be used to measure the pressure after being pressurized by the passive air intake device 1. The thermometer 33 can be used to measure the temperature of the gas after being pressurized by the passive air intake device 1. Combining the gas pressure, composition, and turbine pumping speed, the mass flow rate of the turbine output can be obtained.

[0030] Furthermore, the gas inside cylinder 6 is xenon. Controller 7 can inject a certain proportion of Xe (xenon) into the electric thruster 3 system when atmospheric density increases rapidly during geomagnetic storms, or even shut down turbomolecular pump 2, allowing the electric thruster 3 to operate in pure Xe mode.

[0031] Furthermore, the rotational speed of the turbomolecular pump 2 can be adjusted by the controller 7 according to the density of the ambient gas.

[0032] Specifically, in the multi-gas supply system based on the Kaufman electric thruster provided in this application embodiment, the passive air intake device 1 collects ambient gases (mainly composed of N2, AO and O2) in ultra-low Earth orbit. The passive air intake device 1 pressurizes the collected gas through the ram principle. The pressurized gas is then delivered to the turbomolecular pump 2. The turbomolecular pump 2 further pressurizes the gas and delivers it to the electric thruster 3. The electric thruster 3 generates thrust to compensate for the atmospheric damping force on the spacecraft.

[0033] The mass spectrometer 31 can measure the composition and content of the ambient gas in the orbit of the spacecraft. The vacuum gauge 32 measures the pressure P1 of the ambient gas after it has been pressurized by the passive air intake device 1. The thermometer 33 measures the temperature T1 of the gas output from the passive air intake device 1. By combining the gas composition and content measured by the mass spectrometer 31, the gas density D1 at the inlet of the turbomolecular pump 2 can be obtained.

[0034] An air-breathing electric propulsion system operates at an optimal ambient gas density point (d1). For example, the pressure, temperature, and density of the gas pressurized by the passive air intake device 1 are P1, T1, and D1, respectively. When the spatial density decreases, the controller 7, by collecting the pressure, temperature, and density of the gas pressurized by the passive air intake device 1 (P2, T2, and D2), increases the rotational speed of the turbomolecular pump 2 (it is generally assumed that the composition and content of the orbital gas remain constant) to ensure a relatively stable inlet working fluid mass flow rate for the thruster.

[0035] When fluctuations in ambient gas parameters cause an increase in gas density, the damping force of the spacecraft increases to a certain extent. When events such as geomagnetic storms occur, the ambient gas density increases rapidly, and the damping force of the spacecraft also increases rapidly. In both of these situations, increasing the rotational speed of the turbomolecular pump 2 cannot achieve thrust-resistance balance for the spacecraft because the mass flow rate of the thruster exhibits a saturation phenomenon. That is, when the mass flow rate of the thruster increases to a certain value, the beam current of the electric thruster 3 becomes saturated or even decreases.

[0036] Therefore, under the two scenarios of increased ambient gas density, the controller 7 collects the pressure, temperature, and density of the gas after pressurization by the passive air intake device 1, which are P3 (P4), T3 (T4), and D3 (D4). By adjusting the flow meter 11 of the Xe gas cylinder 6, the working fluid of the electric thruster 3 is made to be a mixture of ambient gas and Xe, or even entirely Xe, thereby improving the performance of the electric thruster 3 (because the performance of the electric thruster 3 with Xe working fluid is significantly higher than that of the electric thruster 3 with ambient gas working fluid), thus achieving thrust-drag balance of the spacecraft.

[0037] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A multi-air supply system based on a Kaufman electric thruster, characterized in that, It includes a passive air intake system, a turbomolecular pump, an electric thruster, a microwave power supply, a microwave neutralizer, a microwave cathode assembly, gas cylinders, and a controller, among which: The passive air intake device is used to collect and compress ambient gas, and its output end is connected to the turbomolecular pump. The turbomolecular pump is connected to the electric thruster via the main intake pipe; The electric thruster is a Kaufman-configured electric thruster, comprising a discharge chamber and the microwave cathode assembly; The microwave power supply is located outside the electric thruster and is connected to the microwave cathode assembly and the microwave neutralizer, respectively. The microwave neutralizer is located at the outlet end of the electric thruster and is connected to the main air intake pipe through a first pipe. The gas cylinder is connected to the main air inlet pipe via a flow meter and a second pipeline; The controller is connected to both the turbomolecular pump and the flow meter. The interior of the discharge chamber is connected to the main air intake pipe via a third pipe and a fourth pipe; The microwave cathode assembly is internally connected to the main air intake pipe via a fifth pipe and a sixth pipe.

2. The multi-air supply system based on a Kaufman electric thruster according to claim 1, characterized in that, The discharge chamber is equipped with a screen and an acceleration grid at its outlet end; a thruster permanent magnet is installed on the outer wall of the discharge chamber.

3. The multi-air supply system based on a Kaufman electric thruster according to claim 2, characterized in that, The microwave cathode assembly is located at the entrance end of the discharge chamber and includes a front magnetic yoke, a reinforcing plate, a microwave antenna, an electron lead-out plate, a microwave cathode permanent magnet, a microwave connector, and a rear magnetic yoke, wherein: The front magnetic yoke is positioned at the front end of the plasma generation region. The reinforcing plate is located in front of the front yoke and is connected to the housing of the microwave cathode. The microwave antenna is disposed inside the discharge chamber of the microwave cathode; The electron lead-out plate is disposed between the front magnetic yoke and the reinforcing plate; The microwave cathode permanent magnet is arranged around the discharge area of ​​the microwave antenna. The rear magnetic yoke is located at the rear end of the plasma generation region. The microwave connector is connected to the microwave antenna and the microwave power supply, respectively.

4. The multi-air supply system based on a Kaufman electric thruster according to claim 3, characterized in that, A first valve is installed on the main intake pipe; a second valve is installed on the first pipe; a third valve is installed on the third pipe; and a fourth valve is installed on the fourth pipe.

5. The multi-air supply system based on a Kaufman electric thruster according to claim 4, characterized in that, It also includes a mass spectrometer, which is located at the input of the passive air intake device and connected to the controller.

6. The multi-air supply system based on a Kaufman electric thruster according to claim 5, characterized in that, A vacuum gauge and a thermometer are installed at the connection between the output end of the passive air intake device and the turbomolecular pump, and the vacuum gauge is connected to the controller.

7. The multi-air supply system based on a Kaufman electric thruster according to claim 6, characterized in that, The gas inside the cylinder is xenon.

8. The multi-air supply system based on a Kaufman electric thruster according to claim 7, characterized in that, The speed of the turbomolecular pump can be adjusted by the controller based on the density of the ambient gas.

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