On-orbit water vapor pressure measurement inversion device and method of lunar soil water molecule mass spectrometer

Abstract

This application relates to the field of vacuum measurement technology, specifically to an on-orbit water vapor pressure measurement and inversion device and method for a lunar soil water molecule mass spectrometer. The device includes a gas sampling device, a vacuum measurement unit, a water molecule mass spectrometer, and a control and processing unit. The gas sampling device is connected to the water molecule mass spectrometer via a gas pipeline and a small orifice. The vacuum measurement unit is located on the gas pipeline, in front of the small orifice. A first valve is installed at the inlet of the vacuum measurement unit, and a second valve is installed at the outlet. The control and processing unit is electrically connected to the gas sampling device, the vacuum measurement unit, and the water molecule mass spectrometer, and is used to perform on-orbit calibration and water vapor pressure inversion calculations. This application utilizes the ultra-high vacuum environment of the lunar surface as a natural zero-pressure reference point, and uses the Pirani vacuum gauge as a reference to perform on-orbit zero-point drift correction on the capacitive thin-film vacuum gauge, ensuring the long-term stability of the pressure measurement reference.

Description

Technical Field

[0001] This application relates to the field of vacuum measurement technology, and more specifically, to an on-orbit water vapor pressure measurement and inversion device and method for lunar soil water molecule mass spectrometer. Background Technology

[0002] Lunar exploration has always been an important direction in the development of the world's space industry. With the rapid development of the space industry, in-situ detection of water ice in the permanently shadowed region of the lunar south pole has also been put into the plan. Among them, time-of-flight mass spectrometer has become an ideal tool for in-situ detection due to its advantages such as fast analysis speed and wide mass range.

[0003] However, the lunar soil water molecule mass spectrometer faces two key challenges to measurement accuracy during its long-term lunar on-orbit mission: First, the performance of the mass spectrometer's core detection components (such as microchannel plates (MCPs) and filaments) degrades or changes over time and usage history, causing drift in its ion current response characteristics and making on-orbit measurement results based on ground calibration data unreliable. Second, the capacitive thin-film vacuum gauge used to measure the pressure in the main pipeline after lunar soil heating exhibits zero-point drift during operation, leading to inaccurate pressure measurement references.

[0004] Currently, there is a lack of an effective method for on-orbit calibration and correction of mass spectrometers and vacuum gauges in a lunar environment, which severely restricts the long-term accuracy and reliability of lunar soil water ice content inversion data. Summary of the Invention

[0005] This application provides an on-orbit water vapor pressure measurement inversion device and method for lunar soil water molecule mass spectrometer, which solves the problem of decreased accuracy of water vapor pressure measurement caused by performance degradation of mass spectrometer unit and zero drift of vacuum gauge during long-term on-orbit operation.

[0006] To achieve the above objectives, this application provides an on-orbit water vapor pressure measurement and inversion device for a lunar soil water molecule mass spectrometer, comprising a gas sampling device, a vacuum measurement unit, a water molecule mass spectrometer, and a control and processing unit. The gas sampling device is connected to the water molecule mass spectrometer via a gas pipeline and a small orifice. The gas sampling device has an internal heating structure filled with solid silver carbonate, and the heating structure is connected to the control and processing unit. The vacuum measurement unit is located on the gas pipeline, in front of the small orifice. A first valve is installed at the inlet of the vacuum measurement unit, and a second valve is installed at the outlet. The vacuum measurement unit includes a Pirani vacuum gauge, a capacitive thin-film vacuum gauge, and a vacuum pipeline. The vacuum pipeline is connected to the gas pipeline, and the Pirani vacuum gauge and the capacitive thin-film vacuum gauge are connected to the vacuum pipeline through their respective interfaces. The control and processing unit is electrically connected to the gas sampling device, the vacuum measurement unit, and the water molecule mass spectrometer, and is used to perform on-orbit calibration and water vapor pressure inversion calculations.

[0007] Furthermore, solid silver carbonate is heated and decomposed through a heating structure to produce carbon dioxide calibration gas.

[0008] Furthermore, the water molecule mass spectrometer is also equipped with a full-range composite vacuum meter.

[0009] Furthermore, the pore size is 1 μm to 10 μm, and its conductivity is constant under molecular flow conditions, which is used to form 10 μm pores within the internal space of the water molecule mass spectrometer. -6 Pa to 10 -4 Stable injection pressure of Pa.

[0010] Furthermore, the first valve is an all-metal diaphragm valve, used to isolate the gas sampling device from the gas pipeline before the calibration gas is introduced; the second valve is an ultra-high vacuum angle valve, used to isolate the vacuum measurement unit from the gas pipeline during the background pumping stage.

[0011] In addition, this application also provides an inversion method for on-orbit water vapor pressure measurement using a lunar soil water molecule mass spectrometer based on a device, comprising the following steps: Step 1: Ground pre-calibrate relative sensitivity by introducing water vapor and carbon dioxide calibration gases respectively, obtain the sensitivity ratio of water vapor to carbon dioxide under ground calibration conditions, and store it in the control processing unit. Step 2: After the on-orbit system has been preheated and stabilized, read the pressure readings of the Pirani vacuum gauge and the capacitive thin-film vacuum gauge. Calculate the zero-point drift of the capacitive thin-film vacuum gauge based on the Pirani vacuum gauge reading, and correct all subsequent pressure measurements. Step 3: During the on-orbit calibration stage, the solid silver carbonate in the gas sampling device is heated to generate carbon dioxide calibration gas, which is then introduced into the gas pipeline. The carbon dioxide gas pressure is measured using a modified capacitive thin-film vacuum gauge. At the same time, carbon dioxide gas is introduced into the water molecule mass spectrometer through a small hole, and the corresponding ion current signal is measured to calculate the on-orbit carbon dioxide sensitivity of the water molecule mass spectrometer. Step 4: Call up the pre-calibrated relative sensitivity on the ground and obtain the current water vapor sensitivity of the water molecule mass spectrometer based on the in-orbit carbon dioxide sensitivity inversion; Step 5: During the lunar soil water ice detection process, water vapor enters the gas pipeline and flows into the water molecule mass spectrometer. The ion flow signal corresponding to the water vapor is measured, and the actual partial pressure of water vapor in the gas pipeline is calculated using the water vapor sensitivity obtained by inversion.

[0012] The on-orbit water vapor pressure measurement and inversion device and method provided in this application for lunar soil water molecule mass spectrometry have the following beneficial effects: This application utilizes the ultra-high vacuum environment of the lunar surface as a natural zero-pressure reference point, and uses the Pirani vacuum gauge as a benchmark to perform on-orbit zero-point drift correction on the capacitive thin-film vacuum gauge, ensuring the long-term stability of the pressure measurement benchmark. By heating solid silver carbonate in orbit to generate controllable and pure carbon dioxide calibration gas to replace water vapor for calibration, the technical difficulties of directly introducing water vapor calibration sources in orbit are avoided. Based on the relative sensitivity of ground pre-calibration, the on-orbit carbon dioxide calibration results are mapped to water vapor sensitivity, realizing self-correction of the attenuation of mass spectrometer response characteristics. Finally, the true partial pressure of water vapor is accurately calculated through inversion formulas, significantly improving the long-term accuracy and reliability of lunar soil water ice detection data. Attached Figure Description

[0013] 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 the structure of the lunar soil water molecule mass spectrometer on-orbit water vapor pressure measurement and inversion device provided in the embodiments of this application; In the diagram: 1-Gas extraction device, 2-Pirani vacuum gauge, 3-Capacitive thin-film vacuum gauge, 4-Vacuum pipeline, 5-First valve, 6-Second valve, 7-Orifice, 8-Water molecule mass spectrometer, 9-Full-range composite vacuum gauge. Detailed Implementation

[0014] 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.

[0015] 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.

[0016] 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.

[0017] 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.

[0018] In addition, the term "multiple" should mean two or more.

[0019] 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.

[0020] like Figure 1 As shown, this application provides an on-orbit water vapor pressure measurement and inversion device for a lunar soil water molecule mass spectrometer, including a gas sampling device 1, a vacuum measurement unit, a water molecule mass spectrometer 8, and a control and processing unit. The gas sampling device 1 is connected to the water molecule mass spectrometer 8 via a gas pipeline and a small orifice 7. The vacuum measurement unit is located on the gas pipeline, in front of the small orifice 7. A first valve 5 is installed at the inlet of the vacuum measurement unit, and a second valve 6 is installed at the outlet. The control and processing unit is electrically connected to the gas sampling device 1, the vacuum measurement unit, and the water molecule mass spectrometer 8, respectively, and is used to perform on-orbit calibration and water vapor pressure inversion calculations.

[0021] Specifically, the on-orbit water vapor pressure measurement inversion device for the lunar soil water molecule mass spectrometer provided in this application establishes an on-orbit water vapor pressure inversion model based on the relative sensitivity obtained from ground calibration. It maps the on-orbit carbon dioxide calibration results to the mass spectrometer's sensitivity to water vapor measurement, thereby accurately inverting the true partial pressure of water vapor based on the measured water vapor ion flow signal during lunar soil water ice detection. By combining on-orbit vacuum gauge calibration with alternative gas calibration, synchronous correction of the mass spectrometer's response characteristics and pressure measurement benchmark is achieved, significantly improving the accuracy and reliability of on-orbit water vapor pressure measurement by the lunar soil water molecule mass spectrometer 8.

[0022] More specifically, the gas sampling device 1 is connected to the water molecule mass spectrometer 8 via a gas pipeline and a small orifice 7, forming a gas flow channel. The vacuum measurement unit is located on the gas pipeline, in front of the small orifice 7, ensuring that pressure measurements are completed before the gas enters the water molecule mass spectrometer 8. A first valve 5 is located at the inlet of the vacuum measurement unit, and a second valve 6 is located at the outlet, used to isolate and control gas flow. The control and processing unit is electrically connected to all components and is responsible for performing on-orbit calibration and water-gas pressure inversion calculations.

[0023] Furthermore, the gas extraction device 1 has an internal heating structure filled with solid silver carbonate, wherein: the heating structure is connected to the control and processing unit; the solid silver carbonate is heated and decomposed through the heating structure to generate carbon dioxide calibration gas. The gas extraction device 1 has an internal heating structure, preferably a heating wire, filled with solid silver carbonate (Ag2CO3). The heating structure is electrically connected to the control and processing unit; during controlled heating, the silver carbonate undergoes a thermal decomposition reaction: , This produces pure carbon dioxide calibration gas, avoiding the technical difficulties of directly using water gas calibration sources in orbit. The gas is generated by solid heating, and the pressure is controllable, the purity is high, and it is easy to implement.

[0024] Furthermore, the vacuum measurement unit includes a Pirani vacuum gauge 2, a capacitive thin-film vacuum gauge 3, and a vacuum line 4, wherein: the vacuum line 4 is connected to the gas line; the Pirani vacuum gauge 2 is installed on the vacuum line 4 to provide a stable zero-pressure reference; and the capacitive thin-film vacuum gauge 3 is installed on the vacuum line 4 to accurately measure the actual pressure of the gas.

[0025] Specifically, the vacuum measurement unit includes a Pirani vacuum gauge 2, a capacitive thin-film vacuum gauge 3, and a vacuum line 4. The vacuum line 4 is connected to the gas line, and the two vacuum gauges are connected in parallel or series on the line. The Pirani vacuum gauge 2 provides a stable zero-pressure reference during the low-pressure phase of the device, and its measurement reading is used for on-orbit correction of the zero-point drift of the capacitive thin-film vacuum gauge 3. In subsequent water and gas measurements, the pressure reading of the capacitive thin-film vacuum gauge 3, after on-orbit zero-point correction, is used as the actual pressure measurement result of the line. The two gauges work together to achieve online zero-point calibration of the capacitive thin-film vacuum gauge 3.

[0026] Furthermore, the exhaust port of the water molecule mass spectrometer 8 is directly exposed to <10 -8 In a vacuum environment of Pa, during lunar soil exploration, the exhaust port of the water molecule mass spectrometer 8 is directly exposed to the ultra-high vacuum environment of the lunar surface, which is better than 10 Pa. -8 Pa ensures that the water molecule mass spectrometer 8 can maintain the necessary working vacuum level, while the lunar vacuum itself can serve as a natural zero-pressure reference source, providing a benchmark for the zero-point calibration of the vacuum gauge.

[0027] Furthermore, the water molecule mass spectrometer 8 is also equipped with a full-range composite vacuum gauge 9, which is used to assist in monitoring the vacuum level at the inlet of the water molecule mass spectrometer 8, ensuring that the inlet pressure is within a safe range during sample injection, and preventing excessive pressure from damaging the mass spectrometer detector.

[0028] Furthermore, orifice 7 is located on the gas pipeline connected to the rear end of vacuum pipeline 4, between the second valve 6 and the water molecule mass spectrometer 8. The orifice 7 has a diameter of 1 μm to 10 μm, and its conductance is constant under molecular flow conditions, used to form a 10 μm orifice within the internal space of the water molecule mass spectrometer 8. -6 Pa to 10 -4 The stable injection pressure is Pa. Orifice 7 is used to continuously and stably introduce a small gas flow rate into the lunar soil water molecule mass spectrometer 8 under on-orbit operating conditions, ensuring that the water molecule mass spectrometer 8 operates in a molecular flow state. The ion flow signal has a linear relationship with the gas pressure, laying the foundation for subsequent sensitivity calculations.

[0029] Furthermore, the first valve 5 is an all-metal diaphragm valve, used to isolate the gas sampling device 1 from the gas pipeline before the calibration gas is introduced; the second valve 6 is an ultra-high vacuum angle valve, used to isolate the vacuum measurement unit from the gas pipeline during the background evacuation stage. The first valve 5, being an all-metal diaphragm valve, is used to isolate the gas sampling device 1 from the gas pipeline before the calibration gas is introduced, preventing premature gas leakage. The second valve 6, being an ultra-high vacuum angle valve, is used to isolate the vacuum measurement unit from the downstream gas pipeline during the background evacuation stage, avoiding back diffusion of downstream gas that could affect the accuracy of pressure measurement. Both valves are ultra-high vacuum compatible valves, ensuring an extremely low system leakage rate.

[0030] In addition, this application also provides an inversion method for on-orbit water vapor pressure measurement using a lunar soil water molecule mass spectrometer based on a device, comprising the following steps: Step 1: Ground pre-calibrate relative sensitivity by introducing water vapor and carbon dioxide calibration gases respectively, obtain the sensitivity ratio of water vapor to carbon dioxide under ground calibration conditions, and store it in the control processing unit. Specifically, the water molecule mass spectrometer prototype 8 was calibrated in a ground-based laboratory. High-purity water vapor and carbon dioxide gas were introduced separately, and their respective sensitivities (S0) were measured and calculated under the same temperature and pressure conditions. H2O地 and S CO2地 Thus, the relative sensitivity S is obtained. r =S H2O地 / S CO2地 . This S r The value is pre-stored as a known constant in the control processing unit. This relative sensitivity remains unchanged under the same water molecule mass spectrometer 8 and is a key parameter for subsequent on-orbit inversion.

[0031] Step 2: After the on-orbit system has been preheated and stabilized, read the pressure readings of the Pirani vacuum gauge 2 and the capacitive thin-film vacuum gauge 3. Calculate the zero-point drift of the capacitive thin-film vacuum gauge 3 based on the reading of the Pirani vacuum gauge 2, and correct all subsequent pressure measurements. Specifically, the water molecule mass spectrometer 8 was powered on and preheated in orbit, entering a stable working state, with its exhaust port exposed to temperatures better than 10°C. -8 The lunar surface ultra-high vacuum environment is measured at Pa. During the stable low-pressure phase of the system (before lunar soil heating), the control and processing unit synchronously reads the reading P from the Pirani vacuum gauge 2. p And the reading P of the capacitive thin-film vacuum gauge 3 c Since the Pirani vacuum gauge 2 has no zero drift, its reading represents the true background pressure (which can be considered as 0). Therefore, the zero drift of the capacitive thin-film vacuum gauge 3 is calculated as Δ = P. c -P p Correct the reading of the capacitive thin-film vacuum gauge 3: P true =P c -Δ, during short-term measurements, the zero-point drift Δ of the capacitive thin-film vacuum gauge 3 remains constant, ensuring the stability of the short-term pressure measurement reference. However, in the lunar orbital environment, the operating temperature of the capacitive thin-film vacuum gauge 3 is precisely controlled, and its zero-point drift characteristics remain stable in the short term (e.g., several hours), thus allowing for correction using the zero-point drift Δ. To further improve the accuracy of long-term measurements, step 2 can be repeated periodically before each subsequent measurement according to the mission plan to re-acquire the Δ value.

[0032] Step 3: In the on-orbit calibration stage, the solid silver carbonate in the gas sampling device 1 is heated to generate carbon dioxide calibration gas and introduced into the gas pipeline. The carbon dioxide gas pressure is measured using the modified capacitive thin-film vacuum gauge 3. At the same time, carbon dioxide gas is introduced into the water molecule mass spectrometer 8 through the small hole 7, the corresponding ion current signal is measured, and the on-orbit carbon dioxide sensitivity of the water molecule mass spectrometer 8 is calculated. Specifically, the first valve 5 and the second valve 6 are closed, and the control processing unit instructs the solid silver carbonate in the gas extraction device 1 to be heated, preferably to 300°C, to generate carbon dioxide calibration gas. The first valve 5 is then opened, allowing CO2 gas to enter the gas pipeline. The actual pressure P of the CO2 gas is measured using the capacitive thin-film vacuum gauge 3, which has been corrected in step 2. CO2 Then, open the second valve 6 to allow CO2 gas to enter the water molecule mass spectrometer 8 through the small hole 7. Before introducing the CO2 gas, measure the background ion intensity of the water molecule mass spectrometer 8 and record it as I. 0CO2 After introducing CO2 gas and waiting for the ion current signal to stabilize, the stable ion current intensity of the water molecule mass spectrometer 8 at this time is measured and recorded as I. CO2 Calculate the change in ion current ΔI CO2 =I CO2 -I0CO2 Then, the CO2 sensitivity of the water molecule mass spectrometer 8 in orbit was calculated: S CO2 =ΔI CO2 / P CO2 .

[0033] Step 4: Call up the pre-calibrated relative sensitivity on the ground and obtain the current water vapor sensitivity of the water molecule mass spectrometer 8 based on the in-orbit carbon dioxide sensitivity inversion; Specifically, the control processing unit calls the ground-pre-stored relative sensitivity S. r The current sensitivity of the mass spectrometer to water vapor is calculated using the inversion formula: S H2O =S CO2 ×S r This step maps the CO2 response measured in orbit to the HO2 response, effectively compensating for the sensitivity drift caused by the degradation of detector gain, electron multiplier efficiency, and other performance factors during long-term operation of the mass spectrometer.

[0034] Step 5: During the lunar soil water ice detection process, water vapor enters the gas pipeline and flows into the water molecule mass spectrometer 8. The ion flow signal corresponding to the water vapor is measured, and the actual partial pressure of water vapor in the gas pipeline is calculated using the water vapor sensitivity obtained by inversion.

[0035] Specifically, during the heating process of the lunar soil sample, the released water vapor enters the gas pipeline through the gas sampling device 1 (silver carbonate is not heated at this time). The water vapor flows through the vacuum measurement unit, and the water vapor pressure is measured using the capacitive thin-film vacuum gauge 3, which has been corrected in step 2. In the actual inversion, the water vapor pressure is not directly measured, but calculated through the ion current signal and sensitivity. That is, the water vapor enters the water molecule mass spectrometer 8 through the small hole 7. Before the water vapor is introduced, the background ion current intensity of the water molecule mass spectrometer 8 is measured and recorded as I. 0H2O After introducing water gas and waiting for the ion current signal to stabilize, the stable ion current intensity of the water molecule mass spectrometer 8 at this time is measured and recorded as I. H2O The change in ion current ΔI was obtained. H2O =I H2O -I 0H2O Then, using the current water vapor sensitivity S obtained in step 4... H2O Calculate the actual partial pressure of water vapor in the gas pipeline: P H2O =ΔI H2O / S H2O Combining the expressions from steps 3 and 5, we obtain the final inversion formula: , Among them, S r This is the relative sensitivity pre-calibrated on the ground. The control and processing unit automatically calculates the water vapor partial pressure based on this formula, which is used to ultimately calculate the lunar soil water ice content.

[0036] More specifically, through the aforementioned apparatus and method, this application achieves high-precision measurement and inversion of water vapor pressure in orbit using the lunar regolith water molecule mass spectrometer 8. Utilizing the ultra-high vacuum environment of the lunar surface as a natural zero-pressure reference, the zero-point drift of the capacitive thin-film vacuum gauge 3 is corrected using the Pirani vacuum gauge 2 as a reference. Carbon dioxide generated by heating silver carbonate is used as a substitute calibration gas, avoiding the difficulties of directly using water vapor for calibration in orbit. Based on the relative sensitivity pre-calibrated on the ground, the in-orbit carbon dioxide sensitivity is mapped to the water vapor sensitivity, thereby establishing a complete inversion chain from ion current signal to the actual water vapor partial pressure. This method effectively suppresses long-term measurement errors caused by the performance degradation of the water molecule mass spectrometer 8 and vacuum gauge drift, significantly improving the reliability of lunar regolith water ice detection data.

[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 lunar soil water molecular mass spectrometer on-orbit water vapor pressure measurement and inversion device, characterized in that, It includes a gas sampling device, a vacuum measurement unit, a water molecule mass spectrometer, and a control and processing unit, wherein: The gas sampling device is connected to the water molecule mass spectrometer via a gas pipeline and a small hole; The gas extraction device is equipped with a heating structure inside and filled with solid silver carbonate. The heating structure is connected to the control and processing unit. The vacuum measuring unit is installed on the gas pipeline, located in front of the small orifice; The vacuum measurement unit is equipped with a first valve at its inlet and a second valve at its outlet. The vacuum measurement unit includes a Pirani vacuum gauge, a capacitive thin-film vacuum gauge, and a vacuum pipeline. The vacuum pipeline is connected to a gas pipeline. The Pirani vacuum gauge and the capacitive thin-film vacuum gauge are respectively connected to the vacuum pipeline through their respective interfaces. The control and processing unit is electrically connected to the gas sampling device, the vacuum measurement unit, and the water molecule mass spectrometer, respectively, and is used to perform on-orbit calibration and water gas pressure inversion calculation.

2. The lunar soil water molecular mass spectrometer on-orbit water vapor pressure measurement and inversion device according to claim 1, characterized in that, The solid silver carbonate is heated and decomposed by the heating structure to produce carbon dioxide calibration gas.

3. The lunar soil water molecular mass spectrometer on-orbit water vapor pressure measurement and inversion device according to claim 1, characterized in that, The water molecule mass spectrometer is also equipped with a full-range composite vacuum meter.

4. The lunar soil water molecule mass spectrometer on-orbit water vapor pressure measurement and inversion device according to claim 1, characterized in that, The pore size is 1 μm to 10 μm, and its conductance is constant under molecular flow conditions, used to form 10 μm in the internal space of the water molecule mass spectrometer. -6 Pa to 10 -4 Stable injection pressure of Pa.

5. The lunar soil water molecular mass spectrometer on-orbit water vapor pressure measurement and inversion device according to claim 1, characterized in that, The first valve is an all-metal diaphragm valve, used to isolate the gas sampling device from the gas pipeline before the calibration gas is introduced; the second valve is an ultra-high vacuum angle valve, used to isolate the vacuum measurement unit from the gas pipeline during the background evacuation stage.

6. A method for inverting on-orbit water vapor pressure measurement using a lunar soil water molecular mass spectrometer based on the apparatus described in any one of claims 1-5, characterized in that, Includes the following steps: Step 1: Ground pre-calibrate relative sensitivity by introducing water vapor and carbon dioxide calibration gases respectively, obtain the sensitivity ratio of water vapor to carbon dioxide under ground calibration conditions, and store it in the control processing unit. Step 2: After the on-orbit system has been preheated and stabilized, read the pressure readings of the Pirani vacuum gauge and the capacitive thin-film vacuum gauge. Calculate the zero-point drift of the capacitive thin-film vacuum gauge based on the Pirani vacuum gauge reading, and correct all subsequent pressure measurements. Step 3: During the on-orbit calibration stage, the solid silver carbonate in the gas sampling device is heated to generate carbon dioxide calibration gas, which is then introduced into the gas pipeline. The carbon dioxide gas pressure is measured using a modified capacitive thin-film vacuum gauge. At the same time, carbon dioxide gas is introduced into the water molecule mass spectrometer through a small hole, and the corresponding ion current signal is measured to calculate the on-orbit carbon dioxide sensitivity of the water molecule mass spectrometer. Step 4: Call up the pre-calibrated relative sensitivity on the ground and obtain the current water vapor sensitivity of the water molecule mass spectrometer based on the in-orbit carbon dioxide sensitivity inversion; Step 5: During the lunar soil water ice detection process, water vapor enters the gas pipeline and flows into the water molecule mass spectrometer. The ion flow signal corresponding to the water vapor is measured, and the actual partial pressure of water vapor in the gas pipeline is calculated using the water vapor sensitivity obtained by inversion.

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