Space micro-thrust engine

Abstract

The application relates to the field of aerospace propulsion technology, in particular to a space micro-thrust engine, which comprises an external supporting cylinder, a grid assembly is fixedly connected to one side of the external supporting cylinder, a flange plate is fixedly connected to the other side of the external supporting cylinder, a hollow cathode assembly is fixedly connected to the middle of the flange plate, the hollow cathode assembly is located in the external supporting cylinder, an annular gas pipe is arranged between the grid assembly and the hollow cathode assembly, one end of the annular gas pipe penetrates through the flange plate, a magnetic field part is arranged on the external supporting cylinder, and the magnetic field part is located at the end far from the flange plate. The application can provide a compact structure and high specific impulse space micro-thrust engine.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of aerospace propulsion technology, in particular to a micro-thrust engine for space. BACKGROUND

[0002] On low earth orbit, microsatellites, micro-nanosatellites have begun to use electric propulsion on a large scale. Due to the self-volume and power supply power limit of microsatellites, the electric propulsion system is required to have the characteristics of small size, low power consumption and high specific impulse. At present, the most commonly used microsatellites are pulse plasma thrusters and field effect electrostatic thrusters, and microsatellites with slightly larger mass have tried to use Hall thrusters, such as FalconSat and Starlink satellites of SpaceX. The efficiency of pulse plasma thruster is generally not more than 10%, and the service life is relatively short, which is generally used for damping compensation and attitude adjustment, not as a propellant. The field effect electrostatic thruster has high specific impulse and small thrust, and has a long service life, which is suitable for long-term tasks with low thrust requirements. Both of them have the risk of tail plume pollution of microsatellites. At present, the Hall thruster and ion thruster used by the mainstream satellite platform have the problem of high difficulty in miniaturization, and further optimization is needed for their application in micro-nanosatellite platform. Therefore, a micro-thrust engine for space is urgently needed to solve the problem. SUMMARY

[0003] The purpose of the present application is to provide a micro-thrust engine for space to solve the above problems and achieve the purpose of providing a micro-thrust engine for space with compact structure and high specific impulse.

[0004] To achieve the above purpose, the present application provides the following scheme:

[0005] A micro-thrust engine for space, comprising an external support cylinder, one side of the external support cylinder is fixedly connected with a grid assembly, the other side of the external support cylinder is fixedly connected with a flange plate, the middle of the flange plate is fixedly connected with a hollow cathode assembly, the hollow cathode assembly is located in the external support cylinder, an annular gas pipe is arranged between the grid assembly and the hollow cathode assembly, one end of the annular gas pipe penetrates through the flange plate, a magnetic field part is arranged outside the external support cylinder, and the magnetic field part is located at the end away from the flange plate.

[0006] Preferably, the grid assembly comprises a screen grid, one end of the screen grid is fixedly connected with the external support cylinder, a plurality of first insulating ceramics and a plurality of acceleration grids are arranged on the side of the screen grid away from the external support cylinder, the plurality of acceleration grids and the plurality of first insulating ceramics are arranged alternately, the acceleration grids and the first insulating ceramics are fixedly connected, and the screen grid is fixedly connected with the first insulating ceramic located at the end.

[0007] Preferably, the hollow cathode assembly comprises a heat shield cylinder, the heat shield cylinder is located in the outer supporting cylinder, the end of the annular gas pipe is located in the gap between the outer wall of the heat shield cylinder and the inner wall of the outer supporting cylinder, the heat shield cylinder is fixedly connected with the flange plate, the heat shield cylinder is sleeved and fixedly connected with a heating part, the heating part is sleeved and fixedly connected with a hot wire ceramic framework, the hot wire ceramic framework is sleeved and fixedly connected with a cathode emission part, one end of the cathode emission part is fixedly connected and communicated with a cathode gas pipe, and the cathode gas pipe penetrates the center of the flange plate.

[0008] Preferably, the cathode emission part comprises a cathode tube, the cathode tube is located in the hot wire ceramic framework, the cathode tube is fixedly connected with the hot wire ceramic framework, the cathode tube is sleeved and fixedly connected with an emitter, and the hot wire ceramic framework is sleeved and fixedly connected outside the cathode tube; the emitter is fixedly connected with a bottom heat shield plate close to one end of the cathode gas pipe, and the emitter is fixedly connected with a cathode top away from the other end of the cathode gas pipe.

[0009] Preferably, the heating part comprises a heating wire, the heating wire is sleeved and fixedly connected outside the hot wire ceramic framework, and one end of the heating wire penetrates the flange plate.

[0010] Preferably, the heat shield cylinder is sleeved and fixedly connected with a heat shield layer, and the heating wire is located in the heat shield layer.

[0011] Preferably, the magnetic field part comprises a coil, the coil is sleeved and fixedly connected outside the outer supporting cylinder.

[0012] Preferably, one end of the outer supporting cylinder is fixedly connected with one end of second insulating ceramic, and the other end of the second insulating ceramic is fixedly connected with the flange plate.

[0013] The present application has the following technical effects: the hollow cathode assembly as an electron source can improve the utilization rate of working gas and the ionization rate of working gas in the main ionization area, thereby improving the specific impulse of the engine. Meanwhile, the annular gas pipe can make the ion distribution in the main ionization area more uniform. The use of the grid assembly can also improve and adjust the thrust of the engine, and the magnetic field part can also increase the discharge efficiency of the main ionization area.

[0014] The present application can also be used for surface potential control of a spacecraft and surface degassing in a vacuum chamber of a large vacuum equipment, and the electron or ion beam current can be extracted by adjusting the voltage in the grid assembly and the potential between the end of the hollow cathode assembly.

[0015] The present application is mainly used for space propulsion and vacuum electron sources. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from these drawings without creative labor.

[0017] Figure 1 Structure diagram of the present application;

[0018] Figure 2 Structure diagram of embodiment 2 of the present application;

[0019] Figure 3 Structure diagram of embodiment 2 of the present application; Figure 2 Enlarged view of part A in the present application;

[0020] Wherein, 1, accelerating grid; 2, screen grid; 3, coil; 4, external support cylinder; 5, annular gas pipe; 6, heat shield cylinder; 7, heat shield layer; 8, hot wire ceramic framework; 9, bottom heat shield sheet; 10, cathode gas pipe; 11, heating wire; 12, cathode tube; 13, emitter; 14, cathode top; 15, first insulating ceramic; 16, second insulating ceramic; 17, flange; 18, vacuum device; 19, bias power supply; 20, particle beam; 21, wire. DETAILED DESCRIPTION

[0021] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0022] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the present application will be further described in detail below with reference to the drawings and specific embodiments.

[0023] With reference to Figure 1 The present application provides a space micro-thrust engine, comprising an external support cylinder, a grid assembly is fixedly connected to one side of the external support cylinder, a flange is fixedly connected to the other side of the external support cylinder, a hollow cathode assembly is fixedly connected to the middle of the flange, the hollow cathode assembly is located in the external support cylinder, an annular gas pipe is arranged between the grid assembly and the hollow cathode assembly, one end of the annular gas pipe passes through the flange, a magnetic field part is arranged outside the external support cylinder, and the magnetic field part is located at the end far from the flange.

[0024] In use, the outer supporting cylinder 4 serves as a holding pole of the hollow cathode assembly and also serves as a mounting of the grid assembly, the cavity between the end of the hollow cathode assembly and the grid assembly forms a main ionization area, the working gas enters the hollow cathode assembly and is ionized in the hollow cathode assembly, the electrons generated in the hollow cathode assembly are introduced to the grid assembly by the working gas, the electrons are accelerated and released through the grid assembly to form an electron beam, the electron beam collides with the gas in the annular gas pipe 5 before passing through the grid assembly, the discharge oscillation in the cavity between the grid assembly and the end of the hollow cathode assembly is weakened, the stability of the discharge is improved, and the corrosion degree of each part is reduced, the service life of each part is increased, the magnetic field part of the outer supporting cylinder 4 sleeve introduces ions into the grid assembly by changing the strength of the magnetic field, and the discharge efficiency of the main ionization area is improved.

[0025] The hollow cathode assembly can improve the utilization rate of the working gas and the ionization rate of the working gas in the main ionization area, thereby improving the specific impulse of the engine. Meanwhile, the annular gas pipe 5 can make the ion distribution of the main ionization area more uniform. The use of the grid assembly can also improve and adjust the thrust of the engine, and the magnetic field part can also increase the discharge efficiency of the main ionization area.

[0026] The application can also be used for surface potential control of a spacecraft, and the electron or ion beam is introduced by adjusting the voltage in the grid assembly and the potential between the end of the hollow cathode assembly.

[0027] The application is mainly used for space propulsion and vacuum electron sources.

[0028] In the application, the outer supporting cylinder 4 and the flange plate 17 are fixed together through an insulator.

[0029] Further optimization scheme, the grid assembly includes a screen grid 2, the screen grid 2 is fixed to one end of the outer supporting cylinder 4, a plurality of first insulating ceramics 15 and a plurality of acceleration grids 1 are arranged on the side of the screen grid 2 away from the outer supporting cylinder 4, the plurality of acceleration grids 1 and the plurality of first insulating ceramics 15 are arranged alternately, the acceleration grid 1 is fixed to the first insulating ceramic 15, and the screen grid 2 is fixed to the first insulating ceramic 15 at the end.

[0030] The plurality of acceleration grids 1 and the screen grid 2 constitute the grid assembly, the grid assembly at least has the screen grid 2, according to the requirements of thrust and specific impulse, the plurality of acceleration grids 1 can be increased to realize the increase of thrust and specific impulse, the adjacent acceleration grids 1 are fixed through the first insulating ceramic 15, the acceleration grid 1 and the screen grid 2 are also fixed through the first insulating ceramic 15, the electrical isolation between the plurality of acceleration grids 1 and between the acceleration grid 1 and the screen grid 2 is realized through the first insulating ceramic 15, and the spacing between the plurality of acceleration grids 1 and the spacing between the acceleration grid 1 and the screen grid 2 are designed according to the size of the thrust.

[0031] By using the potential difference between the screen grid 2 and the acceleration grid 1, the electron acceleration ejection is realized.

[0032] There is also a potential difference between adjacent acceleration grids 1, and as the number of acceleration grids 1 increases, the electron acceleration level also increases, thereby realizing multi-stage acceleration.

[0033] The application preferably has one acceleration grid 1 and one screen grid 2.

[0034] The acceleration grid 1 and the screen grid 2 are provided with through holes, and the number and arrangement of the through holes are different according to different thrust designs, and the through hole distribution design implementation is not limited to uniform arrangement.

[0035] Generally, the center hole density is high and the edge hole density is low.

[0036] The acceleration grid 1 and the screen grid 2 are generally made of corrosion-resistant refractory metal, and the typical material is molybdenum, and they can also be designed as titanium, tantalum and other metals according to the service life.

[0037] The screen grid 2 and the top of the external support cylinder 4 form the cathode external discharge area, which can improve the ionization rate of the working gas.

[0038] At the same time, the working gas in the annular gas pipe 5 can also weaken the discharge oscillation of this part, increase the stability of the discharge and reduce the corrosion degree of each part, and increase the service life of each part. The annular gas pipe 5 is generally provided with holes on the inner side, and the hole spacing is uniform. The annular gas pipe 5 can be made of stainless steel material to form a closed ring.

[0039] The cold working gas injected into the annular gas pipe 5 can not only reduce the energy of high-energy ions in the ionization area, but also provide ions and supplement electrons for the engine. The gas supply pipe position of the annular gas pipe 5 is not limited to the inside, and according to the structural characteristics, it can also be inserted into the main ionization area through the outside of the external support cylinder 4.

[0040] In the application, the hollow cathode assembly is a key component in the electric propulsion system, which provides electron maintenance plasma discharge and neutralizes the function of the plume. The hollow cathode assembly has the characteristics of simple structure, small size, reliable operation and long service life.

[0041] At the same time, the hollow cathode assembly as a kind of small thruster can separate the cathode and the grid assembly, increase the functionality. At the same time, the hollow cathode assembly can use krypton and argon and other rare gases as working gas to participate in discharge, which can greatly reduce the use cost of the propulsion system compared with the use of xenon.

[0042] Further optimization scheme, the hollow cathode assembly includes a heat shield cylinder 6, the heat shield cylinder 6 is located in the outer support cylinder 4, the end of the annular gas pipe 5 is located in the gap between the outer wall of the heat shield cylinder 6 and the inner wall of the outer support cylinder 4, the heat shield cylinder 6 is fixedly connected with the flange plate 17, a heating part is sleeved and fixedly connected in the heat shield cylinder 6, a hot wire ceramic framework 8 is sleeved and fixedly connected in the heating part, a cathode emission part is sleeved and fixedly connected in the hot wire ceramic framework 8, one end of the cathode emission part is fixedly connected and communicated with a cathode gas pipe 10, and the cathode gas pipe 10 penetrates the center of the flange plate 17.

[0043] Further optimization scheme, the cathode emission part includes a cathode tube 12, the cathode tube 12 is located in the hot wire ceramic framework 8, the cathode tube 12 is fixedly connected with the hot wire ceramic framework 8, an emitter 13 is sleeved and fixedly connected in the cathode tube 12, the hot wire ceramic framework 8 is sleeved and fixedly connected outside the cathode tube 12, the emitter 13 is fixedly connected with a bottom heat shield 9 close to one end of the cathode gas pipe 10, and a cathode top 14 is fixedly connected away from one end of the cathode gas pipe 10.

[0044] Further optimization scheme, the heating part includes a heating wire 11, the heating wire 11 is sleeved and fixedly connected outside the hot wire ceramic framework 8, and one end of the heating wire 11 penetrates the flange plate 17.

[0045] The outer support cylinder 4 can be used as a holding electrode of the hollow cathode assembly, and electrons (ions) are led out from the holding electrode, the cathode gas pipe 10, the cathode tube 12, the emitter 13 and the cathode top 14 are arranged in the inner part of the outer support cylinder 4, one end of the cathode gas pipe 10 penetrates the middle part of the flange plate 17, the cathode gas pipe 10 is communicated with the cathode tube 12, the cathode tube 12 is made of refractory metal pipe materials such as tantalum tube or molybdenum-rhenium tube, the emitter 13 is nested in the inner part of the cathode tube 12, the emitter 13 is generally made of barium-tungsten electron emission material or lanthanum hexaboride material, and materials with the characteristics of low electron emission work function can be used for the emitter, one end of the emitter 13 is provided with the bottom heat shield 9, and a through hole is arranged in the middle part of the bottom heat shield 9 to facilitate the passing of working gas. The cathode top 14 is generally made of tungsten or an alloy of tungsten with low work function and high density, the cathode top 14 is welded to the end of the cathode tube 12 away from the cathode gas pipe 10, and a throttle hole is designed in the center of the cathode top 14, and the main purpose is to increase the internal pressure of the emitter, which is beneficial to maintaining gas discharge.

[0046] The working gas enters the emitter 13 through the cathode gas pipe 10, and the working gas is ionized in the emitter 13, the ions in the internal plasma are backstreamed to the surface of the emitter 13, and the cathode part discharge is maintained. The electrons enter the main ionization area through the focusing and acceleration of the cathode top 14.

[0047] The cathode top 14, the cathode tube 12, the emitter 13, the cathode gas pipe 10 and the bottom heat shield 9 are coaxially arranged.

[0048] The heating wire 11 is wound on the heating wire ceramic framework 8 outside the cathode tube 12, and the heating wire 11 is located between the cathode tube 12 and the heat shield cylinder 6, and the cathode tube 12 serves as the cathode of the heating wire 11.

[0049] The heating wire 11 can heat the emitter 13 through the current, and the temperature of the emitter 13 can be increased, and a certain amount of hot emission electrons can be generated, so as to cause the gas in the emitter 13 to be broken down and ionized.

[0050] The way of winding the heating wire 11 on the heating wire ceramic framework 8 is not limited to winding, and the heating wire 11 can be directly embedded in the heating wire ceramic framework 8, or the heating wire ceramic framework 8 is not used, and a double-winding heating mode, a radio frequency heating mode, an eddy current heating mode, etc. are used, and the heating wire current heating mode is not limited.

[0051] In a further optimization scheme, the heat shield cylinder 6 is sleeved and fixed with the heat shield layer 7, and the heating wire 11 is located in the heat shield layer 7.

[0052] In a further optimization scheme, the magnetic field part includes the coil 3, and the coil 3 is sleeved and fixed outside the outer support cylinder 4.

[0053] The electrons in the cathode external discharge area formed by the screen grid 2 and the top of the outer support cylinder 4 can produce Hall drift under the action of the magnetic field and the electric field by electrifying the coil 3 to form an electromagnetic field, so as to ensure the ionization efficiency of the ionization area (discharge area), and the magnetic field can also generate an axial electric field to accelerate ions. The magnetic field can enhance the energy of ions and electrons, and can assist the screen grid 2 and the plurality of acceleration grids 1 to focus the beam.

[0054] The way of generating the magnetic field is not limited to the way of forming the electromagnetic field by the coil 3, and the coil 3 can be replaced by a permanent magnet, and the implementation mode of the magnetic field is not limited to one mode.

[0055] In a further optimization scheme, one end of the outer support cylinder 4 is fixed with one end of the second insulating ceramic 16, and the other end of the second insulating ceramic 16 is fixed with the flange plate 17.

[0056] The working process of the application is as follows: in use, the working gas enters into the emitter 13 from the cathode gas pipe 10, the temperature of the emitter 13 is increased by the heating wire 11 through current heating, and then a certain amount of thermal emission electrons can be generated, so that the working gas is ionized, the ions in the internal plasma are back-bombarded to the surface of the emitter 13, and the cathode part discharge is maintained. The electrons are focused and accelerated into the main ionization area through the cathode top 14, the center of the cathode top 14 is designed with a throttle hole, the main purpose is to increase the internal pressure of the emitter, which is beneficial to maintain the gas discharge, the cold working gas injected into the annular gas pipe 5 can reduce the energy of high-energy ions in the ionization area, and can also provide ions and supplement electrons for the engine. After the electrons enter the screen grid 2, they are sprayed out from the through holes on the surface of the screen grid 2, and then accelerated by the acceleration grid 1 and released outward to generate thrust. Before the electrons enter the screen grid 2, the electrons pass through the electromagnetic field formed by the coil 3, and the electrons produce Hall drift under the action of the magnetic field and the electric field, so as to ensure the ionization efficiency of the ionization area (discharge area), and the magnetic field can also generate an axial electric field to accelerate the ions. The magnetic field can enhance the energy of ions and electrons and can assist the screen grid 2 and the acceleration grid 1 to focus the beam.

[0057] Embodiment 2:

[0058] Reference Figures 2-3 The application can be used for gas removal and cleaning of the inner surface of the vacuum equipment 18. After the surface of the vacuum equipment 18 works for a long time, dust or impurities will accumulate on the inner surface. If the internal working equipment has a high requirement for vacuum degree, the inner surface must be cleaned, otherwise the ultimate vacuum degree of the vacuum equipment and the internal working equipment will be affected.

[0059] One end of the flange plate 17 is fixedly connected to one end of the middle part of the inner side of the vacuum equipment 18, and the outer supporting cylinder 4 is located in the vacuum equipment 18. The screen grid 2 is electrically connected to one end of the bias power supply 19 through the lead wire 21, and the other end of the bias power supply 19 is electrically connected to the edge of the outer wall of the vacuum equipment 18 through another lead wire 21.

[0060] The flange plate 17 of the micro-thrust engine is generally installed at the central axis position inside the vacuum device 18, and can be adjusted according to actual conditions, and there is no special requirement, but a bias power supply 19 needs to be arranged between the micro-thrust engine and the vacuum device 18, and the bias power supply 19 has no position requirement and can be placed inside or outside the vacuum device 18. The bias power supply 19 is used to establish a voltage bias. After the bias power supply 19 is set, an electron beam (low energy) or an ion beam (high energy) is selected for bombardment according to the cleanliness of the inner surface of the vacuum device 18. When the electron beam is selected for bombardment, a negative bias voltage needs to be arranged between the inner surface of the vacuum device 18 and the micro-thrust engine, and the bias voltage is determined according to the actual size of the vacuum device. At this time, a negative bias voltage is arranged between the screen grid 2 in the micro-thrust engine 3 and the cathode top 14, so that the electron beam reaches the screen grid 2 and is emitted under the acceleration of the acceleration grid 1. At this time, the screen grid 2 and the acceleration grid 1 of the micro-thrust engine are different from the thrust mode, and when the entire vacuum device 18 needs to be cleaned, the grid assembly can be designed according to actual needs, for example, the screen grid 2 and the acceleration grid 1 can be designed as a convex structure in this case, so that the internal electrons are emitted in a divergent form. At the same time, if the inner surface of the vacuum device 18 is large, multiple micro-thrust engines can be arranged inside the vacuum device 18 to achieve comprehensive cleaning. When the ion beam is used for cleaning, the setting mode is similar to that of the electron beam, and only the bias power supply 19 needs to be set to a positive bias voltage.

[0061] In the description of the present application, it should be understood that the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0062] The above-described embodiments are only preferred modes of the present application, and do not limit the scope of the present application, and various modifications and improvements to the technical solutions of the present application made by those skilled in the art without departing from the design spirit of the present application shall fall within the protection scope of the present application.

Claims

1. A micro-thrust engine for space use, characterized by: The external support cylinder (4) is fixed with a grid assembly on one side, and a flange plate (17) on the other side, the hollow cathode assembly is fixed in the middle of the flange plate (17) and located in the external support cylinder (4), an annular air pipe (5) is arranged between the grid assembly and the hollow cathode assembly, one end of the annular air pipe (5) penetrates the flange plate (17), and a magnetic field part is arranged outside the external support cylinder (4) and located away from the flange plate (17); The grid assembly comprises a screen grid (2), which is fixed with the external support cylinder (4) on one end, and a plurality of first insulating ceramics (15) and a plurality of accelerating grids (1) are arranged on the side away from the external support cylinder (4), a plurality of the accelerating grids (1) and a plurality of the first insulating ceramics (15) are arranged alternately, the accelerating grids (1) are fixed with the first insulating ceramics (15), and the screen grid (2) is fixed with the first insulating ceramics (15) located at the end. The hollow cathode assembly comprises a heat shield cylinder (6), which is located in the external support cylinder (4), the end of the annular air pipe (5) is located in the gap between the outer wall of the heat shield cylinder (6) and the inner wall of the external support cylinder (4), the heat shield cylinder (6) is fixed with the flange plate (17), a heating part is sleeved and fixed in the heat shield cylinder (6), a hot wire ceramic framework (8) is sleeved and fixed in the heating part, a cathode emission part is sleeved and fixed in the hot wire ceramic framework (8), one end of the cathode emission part is fixed and communicated with a cathode air pipe (10), and the cathode air pipe (10) penetrates the center of the flange plate (17). The annular air pipe (5) is opened on the inner side, and the hole spacing is uniformly distributed.

2. The micro-thruster for space use according to claim 1, characterized by: The cathode emission part comprises a cathode tube (12), which is located in the hot wire ceramic framework (8), the cathode tube (12) is fixed with the hot wire ceramic framework (8), an emitter (13) is sleeved and fixed in the cathode tube (12), the hot wire ceramic framework (8) is sleeved and fixed outside the cathode tube (12), a bottom heat shield plate (9) is fixed at one end of the emitter (13) close to the cathode air pipe (10), and a cathode top (14) is fixed at one end of the emitter (13) away from the cathode air pipe (10).

3. The micro-thruster of claim 1, wherein: The heating part comprises a heating wire (11), which is sleeved and fixed outside the hot wire ceramic framework (8), and one end of the heating wire (11) penetrates the flange plate (17).

4. The micro-thruster of claim 3, wherein: The heat shield cylinder (6) is sleeved and fixed with a heat shield layer (7), and the heating wire (11) is located in the heat shield layer (7).

5. The micro-thruster of claim 1, wherein: The magnetic field part comprises a coil (3), which is sleeved and fixed outside the external support cylinder (4).

6. The micro-thruster of claim 1, wherein: One end of the external support cylinder (4) is fixed with one end of a second insulating ceramic (16), and the other end of the second insulating ceramic (16) is fixed with the flange plate (17).

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