Low-orbit satellite plasma load pollution protection and state diagnosis method

Abstract

The invention discloses a low-orbit satellite plasma load pollution protection and state diagnosis method, and the method comprises the steps: carrying out the pollution protection transformation of the structural design, material selection and the like of a low-orbit satellite plasma load at the design stage of the low-orbit satellite plasma load; in the assembly test stage of the low-orbit satellite plasma load, anti-pollution control is carried out on the test environment cleanliness and the protection device of the low-orbit satellite plasma load; in the in-orbit operation stage of the low-orbit satellite plasma load, in-orbit pollution protection treatment is carried out on the low-orbit satellite plasma load. And according to a preset voltage scanning mode, carrying out pollution state diagnosis on the on-orbit low-orbit satellite plasma load. According to the embodiment of the invention, the deposition of pollutants on the surface layer of the load sensor can be effectively prevented and quickly diagnosed, the pollution damage degree of the load sensor in orbit is reduced, and the observation precision and reliability of low-orbit satellite plasma load data are remarkably improved.

Description

Technical Field

[0001] The present invention relates to the technical field of orbital satellites, and particularly to a method for protecting a low-orbit satellite plasma payload from contamination and diagnosing its state. Background Art

[0002] A low-Earth orbit satellite refers to a satellite that is relatively close to the ground, with an orbital altitude of approximately between 160 kilometers and 2,000 kilometers. A low-orbit satellite orbits the Earth at a very high speed, taking about 90 minutes to 120 minutes to complete one circle. And due to its proximity to the ground, it has advantages in Earth observation, scientific experiments, and some communication tasks. Low-orbit satellites are affected by atmospheric drag and the Earth's gravity, and need to frequently adjust their orbits. Therefore, they are easily affected by the accumulation of pollutants caused by factors such as engine jetting during orbit maintenance.

[0003] The Zhangheng-1 01 satellite is the first geophysical field satellite independently developed by China, which was launched in February 2018 with an orbital altitude of 507 kilometers. The plasma analyzer 1 is one of the eight payloads carried on the satellite, and is used for in-situ observation of ionospheric plasma parameters, including ion density, ion temperature, ion drift velocity, ion composition, and ion density fluctuations. Each sensor and conductor expansion board in the plasma payload 1 are installed on the windward side of the satellite platform, and the sensor inlet is flush with the satellite's surface skin, as Figure 2 shown.

[0004] The plasma analyzer is composed of three sensors and a conductor expansion board in terms of hardware composition 1.1. The above sensors include a retarding potential analyzer 1.2, an ion driftmeter 1.3, and an ion trap 1.4. Among them, the retarding potential analyzer is used to detect the ionospheric plasma density and temperature, the ion driftmeter is used to detect the ion drift velocity, the ion trap is used to detect ion density fluctuation information, and the conductor expansion board is mainly used to increase the conductive area and maintain the uniformity of the electric field at the sensor inlet. Figure 3 The structure schematic diagram of the low-orbit satellite plasma payload is shown.

[0005] The three sensors of the plasma analyzer are all developed from traditional Faraday cups. Taking the retarding analyzer as an example, the front end opening of its sensor is circular, with multiple layers of grids inside, and the bottommost is the current collector. The cross-sectional structure is as Figure 4 shown.

[0006] When the satellite is flying, space plasma (electrons, ions) enters the instrument through the sensor opening. Inside the sensor, the blocking grid maintains a certain bias relative to the instrument ground to prevent electrons in the space plasma from reaching the collector, and to prevent secondary electrons and photoelectrons on the collector from escaping, so as to ensure that the current detected by the collector is completely formed by ions in the plasma. As the scanning bias of the blocking grid gradually changes over time, the collector can obtain the volt-ampere characteristic curve of the ion current changing with the scanning bias. By fitting the volt-ampere characteristic curve, physical quantity data such as ion density, ion temperature, and ion drift velocity can be obtained.

[0007] Soon after the Zhangheng-1 01 satellite entered orbit, it was discovered that the plasma analyzer observation values ​​​​dropped abnormally. After analysis and verification, it was confirmed that the blocking grid and collecting electrode of the plasma analyzer sensor were contaminated in orbit, and tiny components were deposited on the surface to form a contamination layer, which inhibited the sensor's collection current, caused the payload observation sensitivity to decrease, and caused the observed ion density to be too low.

[0008] In addition, affected by the space plasma environment, positive charges will gradually accumulate on the surface of the contaminated layer, causing the positive electric field strength of the contaminated layer to increase, thereby repelling positively charged ions from passing through the grid normally, that is, inhibiting the collector from collecting ions normally, resulting in a phenomenon of reduced on-track collection current, such as Figure 5 shown.

[0009] It can be seen that the pollution layer adsorbed on the surface of satellite payload sensors will cause observation sensitivity attenuation and measurement interference, affecting payload resolution and data accuracy. Therefore, in order to ensure the accuracy of low-orbit satellite observation data and the normal operation of payloads, it is crucial to protect satellite payload sensors in the space environment and reduce the impact of pollution. Summary of the invention

[0010] In view of this, an embodiment of the present invention provides a method for plasma payload contamination protection and status diagnosis of a low-orbit satellite, which at least partially solves the problems existing in the prior art.

[0011] Other features and advantages of the present invention will become apparent from the following detailed description, or may be learned in part by practice of the present invention.

[0012] In order to achieve the above purpose, the embodiment of the present invention provides the following technical solutions:

[0013] According to a first aspect of an embodiment of the present invention, a method for protecting plasma payload from contamination in a low-orbit satellite is provided, the method comprising:

[0014] During the design phase of the low-orbit satellite plasma payload, performing pollution protection modification on the low-orbit satellite plasma payload;

[0015] During the assembly and testing phase of the low-orbit satellite plasma payload, anti-pollution control is carried out on the test environment and protection device of the low-orbit satellite plasma payload;

[0016] During the on-orbit operation phase of the low-orbit satellite plasma payload, on-orbit pollution protection treatment is carried out on the low-orbit satellite plasma payload.

[0017] Furthermore, pollution protection transformation is carried out on the low-orbit satellite plasma payload, including:

[0018] For the conductor extension board of the low-orbit satellite plasma payload, a heating device is installed at the bottom of the conductor extension board. The heating device includes a heating sheet and a thermistor, and the heating device has the heating ability to keep the conductor extension board at 60° for a long time after the satellite is in orbit.

[0019] Furthermore, pollution protection transformation is carried out on the low-orbit satellite plasma payload, and it also includes:

[0020] For the sensor of the low-orbit satellite plasma payload, a titanium alloy plate is used as the blocking grid and the substrate of the collector of the sensor, and the surface coating material of the titanium alloy plate is titanium nitride.

[0021] Furthermore, the sensor collector is fixed on a polyimide insulating board;

[0022] Titanium alloy is used as the material of the external extension rod on the mounting surface of the sensor.

[0023] Furthermore, the sensor includes a retarding potential analyzer, an ion trap meter and an ion drift meter. The sensor is a multi-layer grid structure, including multiple retarding grids and a bottom collector.

[0024] Furthermore, during the assembly and testing phase of the low-orbit satellite plasma payload, anti-pollution control is carried out on the test environment and protection device of the low-orbit satellite plasma payload, including:

[0025] Component assembly and testing of the low-orbit satellite plasma payload are carried out in the clean room of the assembly workshop;

[0026] Before the low-orbit satellite plasma payload is loaded into the fairing of the launch vehicle at the launch site, the inside of the fairing is cleaned using a hundred-thousand-class vacuum cleaner;

[0027] During the period when the low-orbit satellite plasma payload is placed in the fairing of the launch vehicle, a protective cover is used to reduce the exposure time of the plasma payload sensor in the non-clean environment inside the fairing, and the protective cover on the plasma payload sensor is removed 2 to 4 hours before the low-orbit satellite is launched.

[0028] Furthermore, on-orbit contamination protection treatment is performed on the low-orbit satellite plasma payload, including:

[0029] In the initial stage of the low-orbit satellite's orbit insertion, during the remaining time except for briefly powering on the plasma payload to confirm its working state, the plasma payload remains powered off. The heating device on the conductor expansion board of the plasma payload is used to keep the plasma payload sensor in a locally high-temperature state for two months, and then long-term heating control at 10 to 15° is carried out.

[0030] Avoid the jetting period of the low-orbit satellite's attitude control propulsion engine during the brief power-on.

[0031] According to the second aspect of the embodiments of the present invention, a method for diagnosing the contamination state of a low-orbit satellite plasma payload is provided. The contamination state diagnosis method includes:

[0032] According to a preset voltage scanning mode, perform contamination state diagnosis processing on the on-orbit low-orbit satellite plasma payload, and obtain the acquisition current output by the sensor collection electrode of the low-orbit satellite plasma payload.

[0033] If the preset voltage scanning mode is the contamination state inspection mode, determine whether the acquisition current is in a linearly oblique symmetric form.

[0034] If the acquisition current is in a linearly oblique symmetric form, the surface of the sensor of the low-orbit satellite plasma payload is not covered with a contamination layer.

[0035] If the acquisition current is in a non-linearly oblique asymmetric form, the surface of the sensor of the low-orbit satellite plasma payload is covered with a contamination layer. According to the non-linear deviation degree of the acquisition current, determine the severity of the contamination state. To reduce the deposition of the contamination layer, take measures to increase the temperature of the heating sheet installed on the conductor expansion board according to a low-orbit satellite plasma payload contamination protection method according to any one of claims 1 to 7 and adjust the working state of the payload.

[0036] Furthermore, each voltage scanning cycle of the contamination state inspection mode includes a first stage, a second stage, and a third stage.

[0037] In the first stage, raise the voltage from the reference voltage value to the maximum voltage value.

[0038] In the second stage, lower the voltage from the maximum voltage value to the reference voltage value.

[0039] In the third stage, keep no voltage input.

[0040] Further, the preset voltage scanning mode further includes a normal mode, and in each voltage scanning period of the normal mode, the voltage is increased from the reference voltage value to the maximum voltage value;

[0041] In the normal mode, inversion calculation is performed based on the combination of the scanned voltage value and the collected current value to obtain the physical quantity observation value.

[0042] A method for pollution protection and state diagnosis of a low-orbit satellite plasma payload provided by an embodiment of the present invention systematically proposes pollution protection and diagnosis methods for all process links such as the structural design, material selection, assembly test, on-orbit operation, and state diagnosis of the plasma payload based on the research and demonstration results of the sensor pollution phenomenon of the plasma analyzer payload carried by the Zhangheng-1 satellite No. 01 after it is launched into orbit. The embodiment of the present invention can effectively prevent and quickly diagnose the deposition of pollutants on the surface layer of the payload sensor, reduce the degree of pollution damage suffered by the payload sensor in orbit, and significantly improve the observation accuracy and reliability of the low-orbit satellite plasma payload data. The present invention has the characteristics of high operability and great practical value in satellite engineering implementation. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only exemplary, and for those of ordinary skill in the art, other implementation drawings can be obtained by extending according to the provided drawings without creative efforts.

[0044] Figure 1 It is a schematic diagram of the principle of a method for pollution protection and state diagnosis of a low-orbit satellite plasma payload provided by an embodiment of the present invention;

[0045] Figure 2 It is a schematic diagram of the on-satellite installation position of the plasma analyzer provided by an embodiment of the present invention;

[0046] Figure 3 It is a schematic diagram of the hardware structure of the plasma analyzer provided by an embodiment of the present invention;

[0047] Figure 4 It is a schematic diagram of the cross-sectional structure of the sensor provided by an embodiment of the present invention;

[0048] Figure 5 It is a schematic diagram of the influence of the pollution layer on the abnormal ion collection of the sensor provided by an embodiment of the present invention;

[0049] Figure 6 It is a schematic diagram of the voltage scanning normal mode provided by an embodiment of the present invention;

[0050] Figure 7Schematic diagram of the voltage scan pollution state inspection mode provided by the embodiments of the present invention.

[0051] Reference numerals:

[0052] 1 - Plasma analyzer; 1.1 - Conductor extension board; 1.2 - Retarding potential analyzer; 1.3 - Ion drift meter; 1.4 - Ion trap meter. Detailed implementation manners

[0053] In order to enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0054] In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device including a series of steps or units does not necessarily have to be limited to those clearly listed steps or units, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0055] Through the analysis of the defects of the prior art, it is found that the plasma load sensor mainly has the following pollution paths: First, the unburned gas released by the engine nozzle during satellite attitude control and orbit change gradually forms plume molecular deposition; Second, the volatilization and outgassing of satellite thermal control multi-layer materials in high-temperature environments cause small molecule particle deposition; Third, the carried ground pollutants finally form physical adsorption on the satellite surface.

[0056] Based on the analysis and verification of the on-orbit pollution problem of the Zhangheng-1 01 satellite, in the process of developing the Zhangheng-1 02 satellite, a number of protection methods are adopted in the aspects of the structural design, material selection, assembly test, on-orbit operation, and state diagnosis of the plasma load, and a pollution protection and state diagnosis method for the plasma load of a low-orbit satellite is proposed to protect and control the deposition of on-orbit pollutants on the sensor surface to ensure that the satellite load is in a relatively clean working state after entering the orbit. Figure 1 The figure shows a schematic diagram of the principle of the pollution protection and state diagnosis method for the plasma load of a low-orbit satellite provided by the embodiments of the present invention.

[0057] First, the embodiments of the present invention provide a pollution protection method for the plasma load of a low-orbit satellite. Among them, the plasma load is the plasma analyzer. The plasma load includes a sensor and a conductor extension board, and the sensor further includes a retarding potential analyzer, an ion drift meter, and an ion trap meter.

[0058] First, during the design phase of the low-orbit satellite plasma payload, pollution protection transformation is carried out on the low-orbit satellite plasma payload.

[0059] The above steps specifically include:

[0060] The surface of the collector electrode of the plasma analyzer sensor is gold-plated, which is relatively easy to cause pollutant accumulation. By optimizing the collector electrode material to improve the anti-pollution ability of the sensor, combined with the test comparison results, in the embodiments of the present invention, a titanium alloy plate (TC4) is used as the substrate of the blocking grid and the collector electrode of the sensor of the low-orbit satellite plasma payload. The surface coating material of the titanium alloy plate is titanium nitride (TiN), and the above-mentioned collector electrode titanium alloy plate is fixed on a polyimide insulating plate.

[0061] In the embodiments of the present invention, materials with better anti-pollutant deposition characteristics are selected and applied to the outer surface of the sensor, and the surface of the material is specially treated, such as coating or plating, to prevent pollutants from adhering or reducing the influence of pollutant deposition on the sensor surface through chemical reactions.

[0062] In addition, since the plasma payload is installed on the windward side of the satellite, it is necessary to avoid using materials that are prone to outgassing or are easily environmentally polluted (such as organic materials or materials that are prone to accumulating static electricity) near the installation surface to prevent the adsorbable pollutants released by them from adhering to the sensor surface. The telescopic rod device installed around the sensor installation surface should avoid using carbon fiber materials, as there is a possibility that carbon fiber particulate matter will erode and fall off and enter the interior of the sensor, resulting in the accumulation and adhesion of small particulate matter.

[0063] In the embodiments of the present invention, the external telescopic rod material on the installation surface of the sensor of the low-orbit satellite plasma payload is replaced with a titanium alloy material (TC4), which has sufficient strength and stability, can effectively avoid the phenomenon of material erosion and falling off, and can meet the mechanical property requirements and pollution protection requirements during the active section of the satellite.

[0064] Also, since the opening of the plasma analyzer sensor is exposed on the surface of the satellite body, the sensor is surrounded by the thermal control multi-layer of the satellite. In the initial stage of orbit injection, in the high-temperature environment of space sunlight, the thermal control multi-layer material will volatilize a large amount of colloidal small-molecule particulate matter, which is easy to adhere to the sensor surface. In addition, to maintain a relatively stable orbit altitude, the low-orbit satellite will regularly start the engine for orbit maintenance. The main components of the satellite engine propellant are hydrazine and water. Hydrazine decomposes in the space environment to produce plume molecular organic substances such as nitrogen (N2), ammonia (NH3), and monomethylhydrazine (MMH-HNO3), which will deposit after contacting the sensor surface and are prone to physical adsorption.

[0065] According to the principle of gas condensation and deposition, small molecule organic substances in the space environment tend to move from areas with higher temperature to areas with lower temperature. On the other hand, the adsorption time of pollutants on the surface of celestial bodies is mainly determined by the material properties of the adsorption surface and the surface temperature.

[0066] Therefore, the temperature of the sensor surface layer determines the adsorption time and deposition thickness of contaminated organic molecule on the surface of the satellite payload sensor.

[0067] In view of this, in the embodiment of the present invention, a heating device is installed at the bottom of the conductor expansion plate of the low-orbit satellite plasma payload. The heating device includes a heating sheet and a thermistor. After the satellite is launched into orbit, the heating device is controlled to start heating the conductor expansion plate through ground commands, so that its surface temperature is much higher than the temperature of other parts on the windward side of the satellite, thereby preventing the gas released by the satellite from depositing on the sensor surface.

[0068] It has been found through research that the volatilization of small molecule particulate matter in the satellite thermal control multi-layer material is relatively intense in the initial stage of satellite orbit injection, and then gradually decreases with time. In addition, multiple orbit adjustments are required in the initial stage of satellite orbit injection, and the number of engine eruptions is frequent, releasing a large number of gas molecules.

[0069] Therefore, in the initial stage of satellite orbit injection, the heating temperature of the conductor expansion plate is controlled at about 60 °C to ensure the prevention of adsorption of small molecule particulate matter. About two months after orbit injection, long-term heating control is carried out at about 10 to 15 °C, and the specific temperature setting is determined according to the actual on-orbit situation.

[0070] The interior of the sensor of the low-orbit satellite plasma payload is a multi-layer grid structure. Among them, the blocking grid maintains a negative bias relative to the instrument ground, which is used to prevent electrons in the space plasma from reaching the collector, and at the same time prevent secondary electrons and photoelectrons on the collector from escaping, so as to ensure that the current detected by the collector is completely formed by ions in the plasma.

[0071] Next, in the assembly and test stage of the low-orbit satellite plasma payload, anti-pollution control is carried out on the test environment and protection device of the low-orbit satellite plasma payload.

[0072] The above steps specifically include:

[0073] Since one of the pollution paths of the plasma payload sensor is the physical adsorption of ground pollutants on the surface layer of the celestial body, it is necessary to control the environmental cleanliness during the ground assembly and test process.

[0074] First, assemble the payload components and carry out relevant test work in the clean room of the assembly workshop to ensure that the content of dust particles in the air is extremely low and reduce particulate pollution.

[0075] Then, the cleanliness inside the fairing of the launch vehicle is controlled. After the fairing arrives at the launch site, it is thoroughly cleaned. Before the fairing opening, a dedicated hundred-thousand-class vacuum cleaner is used to clean the inside of the fairing to prevent dust particles in the ground environment from entering the load sensor.

[0076] In addition, since the plasma analyzer sensor is installed on the windward side of the satellite, the fixed placement position of the satellite causes the opening direction of this sensor to be directly facing the factory ceiling. Therefore, measures are taken to assemble a protective cover for the sensor. During the long-term placement of the satellite, the protective cover is covered to prevent dust particles floating in the factory ceiling and the space environment from directly falling into the sensor. Since the weakest link in protecting against ground pollutants is the process of placing the satellite in the fairing of the launch vehicle before launch, the embodiment of the present invention can reduce the exposure time of the sensor in a non-clean environment by delaying the removal of the protective cover. A corresponding operation port is specially added inside the fairing of the launch vehicle to remove the protective cover device on the plasma analyzer sensor 2 to 4 hours before the satellite is launched.

[0077] Finally, during the on-orbit operation stage of the low-orbit satellite plasma payload, on-orbit pollution protection treatment is carried out on the low-orbit satellite plasma payload.

[0078] The above steps specifically include:

[0079] Since the volatilization of small-molecule particles of the satellite temperature control multi-layer material is relatively intense in the initial stage of the satellite's orbit entry and then gradually decreases over time, and multiple orbit adjustments are required in the initial stage of the satellite's orbit entry, the number of engine eruptions is frequent, and a large number of gas molecules are released. After the load sensor is powered on and working, the electric field generated by the voltage applied to the blocking grid is likely to attract small-molecule particles in space to attach. Therefore, it is necessary to control the timing of power-on of the load after the satellite enters the orbit.

[0080] In the initial stage of the satellite's orbit entry, except for a short period of power-on of the plasma payload to confirm the working state of the plasma payload, the plasma payload remains powered off during the rest of the time. During this period, the heating device on the conductor expansion board of the plasma payload is used to keep the plasma payload sensor in a locally high-temperature state, thereby reducing the possibility of being contaminated due to gas condensation deposition. It should be noted that the short-term power-on is avoided during the jetting period of the low-orbit satellite. After continuously heating and maintaining the conductor expansion board at a high temperature of 60° for two months, long-term heating control is carried out at about 10 to 15°, and the numerical setting of the heating temperature of the conductor expansion board is further determined according to the analysis results of the load pollution state.

[0081] In addition, the embodiment of the present invention also provides a method for diagnosing the pollution state of a low-orbit satellite plasma payload, including:

[0082] After the plasma payload of the low-orbit satellite is powered on and working, in the normal voltage mode, it linearly rises from the reference value to the maximum value per second, completing a full cycle of voltage scanning (slanting upward), and then starts the voltage scanning of the next cycle. The combination of the scanned voltage value and the current value collected by the collector is used to obtain the physical quantity observation value through inversion calculation, such as Figure 6 as shown

[0083] In order to quickly determine whether the sensor is in a contaminated state and take timely measures to reduce the impact of contamination, in the embodiments of the present invention, a contamination state check voltage scan process (up and down back scan) is performed on the plasma payload of the low-orbit satellite to obtain the collected current output by the sensor collector of the plasma payload of the low-orbit satellite.

[0084] A full cycle of the above contamination state check voltage scan consists of three stages: in the first second, it rises from the reference value to the maximum value to complete the voltage "slanting upward scan", in the second second, it drops from the maximum value to the reference value to complete the voltage "slanting downward scan", in the third second, it remains stationary without voltage output, and then starts the voltage scan of the next cycle Figure 7 The figure shows the schematic diagram of the contamination state check voltage scan.

[0085] Judge whether the collected current is in a linearly slanted symmetric form. Under ideal conditions, the sensor is in a pure resistive state. Therefore, when the scanned voltage "up and down back scans" in the contamination state check mode, the collected current output by the sensor collector presents a linearly slanted symmetric form.

[0086] If the surface of the sensor is covered with a contamination layer, the sensor becomes a non-pure resistive state. Under the resistance-capacitance effect of the contaminant, the collected current output by the collector presents a non-linearly slanted asymmetric form. The greater the degree of non-linear deviation, the more serious the contamination degree. Thus, the contamination state of the sensor is quickly diagnosed to obtain the contamination state diagnosis result, and corresponding disposal measures such as increasing the temperature of the heating sheet of the conductor extension plate and adjusting the working state are carried out.

[0087] The switching between the above normal mode and the contamination state check mode is realized by uploading ground commands.

[0088] In summary, the method for protecting against contamination and diagnosing the state of a low-orbit satellite plasma payload provided by the embodiments of the present invention is based on the research and demonstration results of the contamination phenomenon of the sensors of the plasma analyzer payload carried by the Zhangheng-1 satellite No. 01 after it is launched into orbit. It systematically proposes contamination protection and diagnosis methods for all process links such as the structural design, material selection, assembly and testing, on-orbit operation, and state diagnosis of the plasma payload. The embodiments of the present invention can effectively prevent and quickly diagnose the deposition of contaminants on the surface of the payload sensors, reduce the degree of contamination damage suffered by the payload sensors in orbit, and significantly improve the observation accuracy and reliability of the low-orbit satellite plasma payload data. The present invention can be applied to the design and development of the plasma analyzer payload carried by the subsequent satellites of Zhangheng-1, and is also applicable to plasma observation payloads of the same type of low-orbit satellites. The present invention has the characteristics of high operability and great practical value in the realization of satellite engineering.

[0089] Although the present invention has been described in detail above with general descriptions and specific embodiments, on the basis of the present invention, some modifications or improvements can be made, which are obvious to those skilled in the art. Therefore, these modifications or improvements made without departing from the spirit of the present invention all fall within the scope of protection of the present invention.

[0090] The above are only the preferred embodiments of the present invention, and do not impose any form of limitation on the present invention. Any simple modifications, equivalent changes or decorations made by those skilled in the art using the technical content disclosed above all fall within the protection scope of the present invention.

Claims

1. A method for protecting plasma payload from contamination in a low-orbit satellite, characterized in that: The pollution protection method comprises: During the design phase of the low-orbit satellite plasma payload, performing pollution protection modification on the low-orbit satellite plasma payload; During the assembly and testing phase of the low-orbit satellite plasma payload, anti-pollution control is performed on the test environment and protective devices of the low-orbit satellite plasma payload; During the on-orbit operation phase of the low-orbit satellite plasma payload, the low-orbit satellite plasma payload is subjected to on-orbit pollution protection treatment.

2. A method for protecting plasma payload from contamination of a low-orbit satellite as claimed in claim 1, characterized in that: The low-orbit satellite plasma payload is modified for pollution protection, including: For the conductor extension plate of the low-orbit satellite plasma payload, a heating device is installed at the bottom of the conductor extension plate. The heating device includes a heating plate and a thermistor. The heating device has the ability to keep the conductor extension plate heated at 60° for a long time after the satellite enters orbit.

3. A method for protecting plasma payload from contamination of a low-orbit satellite as claimed in claim 1, characterized in that: The pollution protection modification of the plasma payload of the low-orbit satellite also includes: For the sensor of the plasma payload of the low-orbit satellite, a titanium alloy plate is used as the blocking grid and collecting electrode substrate of the sensor, and the surface coating material of the titanium alloy plate is titanium nitride.

4. A method for protecting plasma payload contamination of a low-orbit satellite as claimed in claim 3, characterized in that: Fixing the sensor collector on a polyimide insulating board; Titanium alloy is used as the material of the external extension rod on the installation surface of the sensor.

5. A method for protecting plasma payload from contamination of a low-orbit satellite as claimed in claim 3, characterized in that: The sensor comprises a blocking potential analyzer, an ion capture meter and an ion drift meter. The sensor is a multi-layer grid structure, comprising a multi-layer blocking grid and a bottom collecting electrode.

6. A method for protecting plasma payload contamination of a low-orbit satellite as claimed in claim 1, characterized in that: During the assembly and testing phase of the low-orbit satellite plasma payload, anti-pollution control is performed on the test environment and protective devices of the low-orbit satellite plasma payload, including: Assembling and testing components of the low-orbit satellite plasma payload in a clean room of an assembly plant; Before the low-orbit satellite plasma payload is loaded into the carrier rocket fairing at the launch site, the inside of the fairing is cleaned using a 1000-class vacuum cleaner; While the low-orbit satellite plasma payload is placed in the fairing of a carrier rocket, a protective cover is used to reduce the exposure time of the plasma payload sensor to the unclean environment in the fairing, and the protective cover on the plasma payload sensor is removed 2 to 4 hours before the launch of the low-orbit satellite.

7. A method for protecting plasma payload contamination of a low-orbit satellite as claimed in claim 1, characterized in that: Performing on-orbit pollution protection treatment on the plasma payload of the low-orbit satellite includes: At the initial stage of the low-orbit satellite entering orbit, except for briefly powering on the plasma payload to confirm the working state of the plasma payload, the plasma payload is kept in a powered-off state, and a heating device on a conductor expansion board of the plasma payload is used to keep the plasma payload sensor in a local high-temperature state, which lasts for two months, followed by a long-term heating control of 10 to 15°; Avoid the jet period of low-orbit satellite attitude control propulsion engines when performing a short power-up.

8. A method for diagnosing the contamination status of plasma payload of a low-orbit satellite, characterized in that: The pollution status diagnosis method comprises: According to a preset voltage scanning mode, a contamination state diagnosis process is performed on a low-orbit satellite plasma payload on orbit, and a collection current output by a sensor collector of the low-orbit satellite plasma payload is obtained; If the preset voltage scanning mode is a pollution state inspection mode, determining whether the collected current is in a linear oblique symmetrical form; If the collected current is in a linear oblique symmetrical shape, the sensor surface of the low-orbit satellite plasma payload is not covered with a contamination layer; If the collected current is in a nonlinear, oblique, asymmetric shape, the sensor surface of the low-orbit satellite plasma payload is covered with a pollution layer. The severity of the pollution state is judged according to the degree of nonlinear deviation of the collected current. In order to reduce the deposition of the pollution layer, measures are taken to increase the temperature of the heating plate installed on the conductor extension board according to the low-orbit satellite plasma payload pollution protection method as described in any one of claims 1 to 7 and adjust the working state of the load.

9. A method for diagnosing the contamination state of plasma payload of a low-orbit satellite as claimed in claim 8, characterized in that: Each voltage scanning cycle of the pollution state inspection mode includes a first stage, a second stage and a third stage; In the first stage, the voltage is increased from a reference voltage value to a maximum voltage value; In the second stage, the voltage is reduced from the maximum voltage value to the reference voltage value; In the third phase, no voltage is input.

10. A method for diagnosing the contamination state of plasma payload of a low-orbit satellite according to claim 8, characterized in that: The preset voltage scanning mode also includes a normal mode, in which each voltage scanning cycle of the normal mode increases the voltage from the reference voltage value to the maximum voltage value; In the normal mode, the inversion calculation is performed based on the combination of the scanned voltage value and the collected current value to obtain the observed value of the physical quantity.

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