A preparation method for different characteristic mars weathering layer simulation objects

Abstract

The present application relates to a kind of preparation methods for different characteristic Mars weathered layer simulation object, comprising: obtaining the chemical element information of real Mars weathered layer, selecting the brown red volcanic rock with approximate chemical characteristics as raw material and drying;The dry raw material is pulverized, classified and screened, and a plurality of particle size components are obtained;Design different types of target particle size grading, to simulate the typical mechanical properties of different regions on the surface of Mars, each grading can be used as dry state regolith sample.Add water or salt solution to dry state regolith sample, and form frozen sample by low temperature, to simulate high latitude or shallow ice frozen environment on Mars.In addition, secondary mineral powder can also be added to simulate the surface environment of Mars after acidification or salinization weathering, to realize more complex chemical characteristics demand.The present application is simple in process, suitable for mass production, and the simulation object and Mars weathered layer have good correspondence in chemical composition, physical and mechanical properties, and simulation regolith can be produced to cope with various working conditions.

Description

Technical Field

[0001] This invention relates to the fields of aerospace research and extraterrestrial environment simulation technology, and in particular to a method for preparing Martian regolith simulators with different characteristics. Background Technology

[0002] As Mars exploration activities progress, the impact of Martian regolith on the mission has become a key aspect of aerospace engineering. However, due to current technological limitations, it is difficult to bring back large quantities of in-situ samples from Mars. Furthermore, the Martian surface environment is complex, with varying characteristics of regolith in different regions, and the process of obtaining samples faces risks and uncertainties. Therefore, preparing simulants with properties similar to Martian regolith on Earth has become a necessary means to support the design and verification of Mars exploration missions.

[0003] By preparing simulated Martian soil samples, researchers can conduct extensive experimental studies under relatively safe and controllable conditions, simulating the extreme Martian environment on the ground. These studies include landing buffer tests, rover obstacle-crossing performance evaluations, slope stability analysis, in-situ resource utilization verification, and adaptability testing of sampling devices. This not only reduces the engineering risks and costs of actual exploration missions but also provides crucial scientific data and technical support for the design and optimization of exploration instruments, the formulation of Mars mission strategies, and future human landing plans on Mars.

[0004] Currently, various simulated fire soils have been developed, such as JSC Mars-1 (Allen et al., 1998), MMS Sand (Peters et al., 2008), JMSS-1 (Zeng et al., 2015), the JLU Mars series (Xue, 2017), TJ-M1 (Jiang et al., 2020), and NEU Mars-1 (Guan et al., 2020), which exhibit varying degrees of realism in terms of mineral composition, density, porosity, and strength. However, these simulated fire soils are developed for different engineering purposes, lacking a unified preparation standard, and the characteristics of the obtained simulated fire soils are relatively singular, lacking multi-objective characteristic control schemes.

[0005] Therefore, in order to further improve the simplification of the process, the gradation control scheme, the adaptability to multiple working conditions, and the adaptability to large-scale preparation of Martian regolith simulants, there is an urgent need for a preparation method for Martian regolith simulants with different properties. Summary of the Invention

[0006] The purpose of this invention is to provide a method for preparing Martian regolith simulants with different characteristics. The process is simple, adaptable to various working conditions, and the prepared simulants can be used for ground verification tests and scientific research related to different types of Martian regolith, meeting the experimental needs of complex Martian surface exploration projects, and can be mass-produced.

[0007] The objective of this invention can be achieved through the following technical solutions:

[0008] This invention provides a method for preparing Martian regolith simulators with different characteristics, characterized by comprising the following steps:

[0009] S1. Identify the raw materials based on the chemical elemental composition characteristics of the Martian regolith, and then dry the raw materials.

[0010] S2. The dried raw material is placed in a planetary ball mill for multi-stage ball milling and pulverization, and then classified and screened to obtain particles of different particle size ranges and sealed for storage.

[0011] S3. Based on the in-situ particle size distribution curve of Mars, design the gradation of different Martian regolith simulated materials;

[0012] S4. According to the gradation of the Martian regolith simulator, mix particles of different size ranges in proportion to obtain a dry Martian regolith simulator.

[0013] S5. Introduce pure water or salt solution into the dry Martian regolith simulator, stir evenly, and freeze at low temperature to form a stable ice-containing structure, thus obtaining an ice-containing Martian regolith simulator.

[0014] S6. Secondary minerals are introduced into the dry Martian regolith simulator and stirred evenly under constant temperature conditions to obtain a Martian regolith simulator containing secondary minerals.

[0015] Preferably, step S1 specifically refers to: obtaining the chemical element composition information of the Martian regolith and selecting brownish-red natural volcanic rock with a similar chemical composition as raw material.

[0016] More preferably, step S1 specifically includes:

[0017] Step S1-1: Obtain chemical element information of the actual Martian regolith;

[0018] Step S1-2: Collect various natural volcanic rock samples with similar appearances, perform X-ray fluorescence spectroscopy (XRF) and other analyses to determine the main chemical element composition, and select samples that are similar to Martian soil data as raw materials.

[0019] Preferably, in step S1, the main oxide composition of the brownish-red natural volcanic rock includes SiO2, Fe2O3, Al2O3, MgO, and CaO, and the main mineral composition includes pyroxene, plagioclase, and olivine.

[0020] Preferably, in step S1, the drying process refers to drying continuously at a drying temperature of 105℃-110℃ for 5-8 hours, and the drying is considered complete when the change in the mass of the raw material is less than 0.1wt.%.

[0021] More preferably, in step S1, the drying process refers to: placing the raw material in a drying oven and drying it for 6 hours at a temperature of about 105℃-110℃. During the drying process, the change in the quality of the raw material is continuously monitored, and when the change in quality is less than 0.1wt.%, the drying is considered to be complete.

[0022] Preferably, in step S2, the dried raw material is pulverized in multiple stages and graded and sieved, so that the particle size distribution of the resulting particles covers the true particle size range of the Martian regolith.

[0023] Preferably, in step S2, the planetary ball mill includes a four-tank high-speed planetary ball mill.

[0024] Preferably, in step S2, the particle size range includes four types, specifically 0.5-2.5 mm, 0.25-0.5 mm, 0.075-0.25 mm, and 0-0.075 mm.

[0025] Preferably, step S2 includes the following specific steps:

[0026] S2.1 First, a four-tank high-speed planetary ball mill is used to perform multi-stage ball milling on the dried raw materials. By controlling different combinations of rotation speed and ball milling time parameters, particles with different particle size characteristics are prepared. Specifically: using a rotation speed of 300 rpm and a grinding time of 10 minutes, coarse particles of 2-5 mm are obtained; using a rotation speed of 400 rpm and a grinding time of 20 minutes, medium-coarse particles of 0.5-2 mm are obtained; using a rotation speed of 400 rpm and a grinding time of 30 minutes, relatively fine particles of 0.1-0.5 mm are obtained; using a rotation speed of 500 rpm and a grinding time of 35-40 minutes, extremely fine particles of <0.1 mm are obtained.

[0027] S2.2 The particles obtained after ball milling are vibrated and sieved using a combination of sieves with apertures of 2.5 mm, 0.5 mm, 0.25 mm and 0.075 mm respectively. Ultrasonic sieving is used for ultrafine particles with a particle size of less than 0.075 mm to improve accuracy and prevent agglomeration of fine particles, and finally particles in the four particle size ranges are obtained.

[0028] Preferably, in step S3, referring to the particle size distribution of the weathered layer particles on the surface of the Martian soil obtained by remote sensing, at least three in-situ particle size distribution curves of Mars (such as loose sandy area, medium dense area and dense compacted area) are preset according to the Mars microscopic imager. The three in-situ particle size distribution curves of Mars correspond to three gradations of Martian weathered layer simulation materials, and each gradation matches the typical mechanical properties of different areas on the Martian surface.

[0029] Preferably, in step S3, the Martian regolith gradation includes at least three types, namely gradation 1, gradation 2, and gradation 3.

[0030] More preferably, in step S3, gradation 1 comprises: 22 wt.% of 0.5-2.5 mm particles with an allowable error of ±3%; 26 wt.% of 0.25-0.5 mm particles with an allowable error of ±3%; 32 wt.% of 0.075-0.25 mm particles with an allowable error of ±3%; and 20 wt.% of 0-0.075 mm particles with an allowable error of ±3%; the internal friction angle of gradation 1 is 20°-30°.

[0031] More preferably, in step S3, gradation 2 comprises: 34 wt.% of particles with a tolerance of ±3% for 0.5-2.5 mm, 47 wt.% of particles with a tolerance of ±3% for 0.25-0.5 mm, 11 wt.% of particles with a tolerance of ±3% for 0.075-0.25 mm, and 8 wt.% of particles with a tolerance of ±3% for 0-0.075 mm; the internal friction angle of gradation 2 is 30°-40°.

[0032] More preferably, in step S3, gradation 3 comprises: 86 wt.% of particles with a tolerance of ±3% for 0.5-2.5 mm, 9 wt.% of particles with a tolerance of ±3% for 0.25-0.5 mm, 4 wt.% of particles with a tolerance of ±3% for 0.075-0.25 mm, and 1 wt.% of particles with a tolerance of ±3% for 0-0.075 mm; the internal friction angle of gradation 3 is 40°-45°.

[0033] Preferably, in step S4, particles of different particle size ranges are mixed in proportion according to the target particle size distribution to obtain a dry Martian regolith simulator with the target mechanical properties.

[0034] Preferably, in step S5, under low temperature conditions, pure water or salt solution is sprayed onto the dry Martian regolith simulator with the target mechanical properties in a target ratio, and then frozen into a stable ice-containing structure to obtain an ice-containing Martian regolith simulator with the target ice content and ice crystal size.

[0035] Preferably, in step S5, the salt solution includes either MgSO4 or NaCl aqueous solution.

[0036] Preferably, in step S5, the low temperature condition refers to a temperature equal to or lower than -20°C.

[0037] Preferably, in step S5, the ice content of the ice-containing Martian regolith simulator is 0.5-20 wt.%, to simulate the polar or mid-latitude permafrost environment of Mars.

[0038] More preferably, in step S5, the dry Martian regolith simulator is mixed thoroughly with different proportions of pure water or salt solution, and sealed and stored at a temperature equal to or below -20°C to prevent moisture sublimation loss.

[0039] Preferably, in step S6, secondary minerals are introduced into the dry Martian regolith simulator with the target mechanical properties to simulate the chemical characteristics under acidic or saline weathering conditions, thereby obtaining a Martian regolith simulator containing secondary minerals with the target chemical characteristics.

[0040] Preferably, in step S6, the secondary minerals include any one or more of sulfates, carbonates, chlorides, magnetite, and hematite.

[0041] More preferably, in step S6, the secondary mineral has a powder structure, and the particle size is based on the gradation curve.

[0042] Preferably, in step S6, the total proportion of secondary minerals in the Martian regolith simulator containing secondary minerals does not exceed 20 wt.%.

[0043] More preferably, the concentration of various secondary mineral components in the simulated Martian regolith containing secondary minerals should be referenced to the concentration of real Martian regolith soil, in order to reproduce the Martian surface environment of a specific region.

[0044] Preferably, in step S6, the constant temperature condition refers to 22-27℃.

[0045] Preferably, X-ray fluorescence spectroscopy (XRF), laser particle size analysis, densitometer, and triaxial compression tests are used to conduct a series of characteristic tests on Martian regolith simulants with different properties, including tests on chemical composition, particle size distribution, density, and mechanical properties. The mechanical properties include at least tests on the internal friction angle and cohesion. The test results are compared with preset targets. If the measured results deviate from the target range, feedback correction is performed by adjusting the ratio of coarse to fine particles, ice content, or the proportion of other minerals until the properties meet the target indicators.

[0046] Preferably, in step S4, the obtained dry Martian regolith simulator is subjected to mechanical property testing, which includes at least internal friction angle and cohesion testing; the measured mechanical property values ​​are compared with the target index; if the measured values ​​deviate from the target index, the mixing ratio of particles in different particle size ranges is adjusted to correct the deviation until the mechanical properties of the dry Martian regolith simulator meet the target index.

[0047] Preferably, in step S5, the ice content and ice crystal size of the obtained ice-containing Martian regolith simulator are tested, and the measured values ​​of ice content and ice crystal size are compared with the corresponding target indicators. If the measured value of ice content deviates from the target indicator, the water content of the simulator is adjusted by adjusting the amount of pure water or salt solution introduced into the dry Martian regolith simulator until the target indicator is reached. If the measured value of ice crystal size deviates from the target indicator, the uniform mixing and freezing time are adjusted until the target indicator is reached.

[0048] Preferably, in step S6, the chemical composition of the obtained Martian regolith simulation containing secondary minerals is tested, and the measured chemical composition is compared with the target index. If the measured result deviates from the target index, it is corrected by adjusting the type and proportion of the introduced secondary minerals until the chemical composition meets the target index.

[0049] More preferably, the Martian regolith simulants with different properties can be prepared individually or mixed in proportion to obtain samples with comprehensive properties. For example, based on dry soils (loose, medium-dense, and dense samples) with different typical mechanical properties, the ice content of the samples can be adjusted to study the effect of water ice on the mechanical properties of Martian soil. In addition, the composition and proportion of secondary minerals can be adjusted in base samples with different ice contents to study the thermal properties of Martian soils with different mineral compositions at high latitudes.

[0050] The present invention also provides a Martian regolith simulator with different characteristics prepared according to the preparation method described above, wherein the Martian regolith simulator includes a dry Martian regolith simulator, an ice-containing Martian regolith simulator, or a Martian regolith simulator containing secondary minerals.

[0051] Preferably, the Martian regolith simulator has adjustable mechanical properties, ice content, and chemical composition, and the simulator can be used for Mars landing buffer experiments, wheel drive performance experiments, drilling and sampling experiments, and in-situ resource utilization.

[0052] This invention proposes a method for preparing Martian regolith simulators with different properties. Based on planetary ball milling technology, this method allows for precise control of particle size distribution, effectively improving the ability to regulate the mechanical properties of particles and enabling the preparation of Martian regolith simulators, i.e., Martian soil, with different target mechanical properties. Simultaneously, the method can recreate the shallow permafrost environment of Mars by introducing water or salt solutions at low temperatures to form stable ice-containing structures; and by introducing secondary minerals such as sulfates and chlorides, it can simulate the weathering and chemical evolution processes of the Martian surface.

[0053] The simulants prepared by this invention can be specifically controlled in terms of chemical composition, physical structure and mechanical response according to research needs. They are both reproducible and scalable, and can provide reliable support for subsequent ground experiments, detector interaction experiments and in-situ resource utilization research.

[0054] Compared with the prior art, the present invention has the following beneficial effects:

[0055] (1) This invention provides a method for preparing Martian regolith simulants with different characteristics. Based on the chemical elemental composition and in-situ particle size distribution curve of the real Martian regolith, raw materials with similar chemical compositions are screened. After drying, crushing and sieving, different gradations are designed. Each gradation can serve as a dry regolith sample with different mechanical properties. By introducing water or salt solution into the dry regolith sample and freezing it at low temperature, an ice-containing regolith sample can be obtained. By introducing secondary minerals into the dry regolith sample, a secondary mineral-containing regolith sample can be obtained. This preparation process is simple, adaptable to various working conditions, and can be mass-produced. The products can meet the needs of ground verification tests and scientific research related to the Mars exploration project.

[0056] (2) This invention uses planetary ball milling technology to crush volcanic rock raw materials, which can flexibly optimize parameters such as ball milling time, rotation speed, and ball-to-material ratio, significantly improving the preparation efficiency of particles within the target particle size range. Subsequent use of vibrating sieving and ultrasonic sieving technologies achieves fine particle size classification, ensuring the accurate implementation of the gradation design. The entire process does not rely on complex equipment, and parameter control is convenient. It can meet the needs of small-batch preparation in the laboratory and can also achieve large-scale production, possessing strong engineering operability.

[0057] (3) Based on in-situ data such as the Mars Microscopic Imager, this invention designs different types of simulated particle size distributions. By adjusting the particle size distribution, the resulting simulated particles are highly consistent with the actual Martian soil in terms of particle size composition. At the same time, it achieves controllable preparation for different application requirements (such as mechanical properties, ice-containing properties, or chemical reactivity): for simulated Martian soil with different mechanical properties, key parameters such as dry density, internal friction angle, and cohesion can be flexibly controlled by adjusting the particle size and ratio; for the simulation requirements of ice-containing or acidic environments, humidity control, temperature control, and chemical addition steps can be further introduced to reproduce diverse Martian surface environments.

[0058] (4) This invention enables the customized preparation of various types of fire and soil simulants. The method is simple, the parameters are controllable, and the scope of application is wide. It can meet diverse experimental needs, such as obstacle crossing tests of probes, in-situ sampling and resource utilization assessment, etc. It is applicable to Mars-related ground verification tests and the study of surface materials of other terrestrial bodies. It has strong engineering adaptability and application promotion value. Attached Figure Description

[0059] Figure 1 This is a flowchart of a method for preparing Martian regolith simulators with different characteristics according to the present invention;

[0060] Figure 2 The particle size distribution curves of real in-situ volcanic soil and other simulated materials are used as references in this invention.

[0061] Figure 3 The simulated fire soil particle size distribution curve prepared for this invention.

[0062] Figure 4 The shear strength of the simulated samples under different ice-containing conditions was measured. Detailed Implementation

[0063] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0064] Unless otherwise specified, the reagents, methods, instruments, and equipment used in this invention are conventional in the art. Unless otherwise specified, the reagents and materials used in the following examples are all commercially available.

[0065] Example 1

[0066] This embodiment provides a method for preparing Martian regolith simulators with different characteristics, including:

[0067] (1) Raw material selection

[0068] Table 1 Chemical element data of Martian regolith

[0069]

[0070] The preparation process flowchart of the fire-soil simulant of the present invention is shown below. Figure 1 Based on the chemical composition data of the in-situ Martian regolith, see Table 1 ( a Banin et al., 1992; b Wänke et al., 2001; cGellert et al., 2004; d Rieder et al., 2004; e Blake et al. (2013) used natural brownish-red volcanic rock as raw material, prioritizing comparative analysis of volcanic rocks with similar main chemical element contents. Ultimately, a volcanic rock with main chemical components matching Martian regolith data and exhibiting a Martian-like reddish-brown color was selected as the raw material. This raw material originated from Helingeer County, Hohhot City, Inner Mongolia.

[0071] (2) Raw material pretreatment

[0072] The raw materials were placed in an electric heating drying oven and dried at 110℃ for 8 hours. During this period, the materials were weighed every 0.5 hours. The drying process was considered complete when the difference between two consecutive weighings was less than 0.1%.

[0073] (3) Planetary ball milling and sieving

[0074] A planetary ball mill was used, loaded with agate balls and the sample. Different rotation speeds and milling times were set according to the particle size range: 2-5 mm coarse particles were milled at 300 rpm for 10 minutes; 0.5-2 mm medium-coarse particles at 400 rpm for 20 minutes; 0.1-0.5 mm relatively fine particles at 400 rpm for 30 minutes; and <0.1 mm extremely fine particles at 500 rpm for 35-40 minutes. Preliminary pulverized samples were obtained (different rotation speeds and milling times were set according to the target particle size range).

[0075] After pulverization, the particles were vibrated and sieved using a combination of sieves with apertures of 2.5 mm, 0.5 mm, 0.25 mm, and 0.075 mm. Particles smaller than 0.075 mm were subjected to ultrasonic sieving to improve accuracy and prevent agglomeration of fine particles. The sieving yielded four particle size fractions: a) 0.5 mm–2.5 mm; b) 0.25 mm–0.5 mm; c) 0.075 mm–0.25 mm; d) < 0.075 mm. Samples of each particle size fraction were sealed and stored in a desiccator to prevent moisture absorption and contamination.

[0076] (4) Gradation mixing and preparation of simulated samples

[0077] (4a) Based on the Martian in-situ particle size distribution curve ( Figure 2a) (Herkenhoff et al., 2004; Arvidson et al., 2010; Siebach et al., 2010), designed three simulated fire-soil target gradations. Due to the resolution limitations of the Mars microscopy imager (approximately 100), μm Particles smaller than this threshold cannot be captured. However, considering that fine particles exist in the actual Martian regolith, based on other simulated Martian soil gradation curves (…),… Figure 2 (b) (Allen et al., 1998; Peters et al., 2008; Zeng et al., 2015; Xue, 2017; Jiang et al., 2020; Guan et al., 2020) added a certain proportion of fine particles in the design of the simulated material gradation to better reproduce the particle size distribution of natural pyrophyllite. Figure 3 Subsequently, based on the mass of the samples obtained from sieving at each particle size range, they were precisely weighed and mixed according to the target ratio. Mixing ensured that the components were evenly distributed, resulting in three gradations of simulated fire soil samples, which can be used as dry simulated fire soil with three different mechanical properties.

[0078] (4b) Based on the preparation of dry simulated fire soil, a water-ice mixing process under controlled temperature was adopted. First, pure water or salt solution was slowly sprayed into the dry fire soil to achieve different target ice content ratios (e.g., 5 wt.%, 10 wt.%, 15 wt.%). Then, the mixed sample was placed in a low-temperature stirring device for continuous mixing to ensure uniform distribution of the liquid phase between particles. After completion, it was immediately stored at ≤20℃ to maintain the ice content. According to experimental requirements, the thermodynamic and mechanical response characteristics of fire soil at different latitudes and burial depths can be simulated by adjusting the ice content and ice crystal size.

[0079] (4c) To simulate the secondary mineral environment formed by hydration or acidification of the Martian surface, specific chemical components are introduced into dry simulated marshland samples. Specifically, this includes adding mineral powders such as sulfates, magnetite, and hematite to a target proportion of the marshland sample, with each component added in a proportion controlled between 0.1-5 wt.% of the total mass. Subsequently, the sample is thoroughly stirred under constant temperature conditions (approximately 25°C) to allow ion adsorption and surface reactions to begin, thereby forming a marshland sample containing secondary minerals. This type of sample can be used to simulate experimental scenarios such as the Martian acidic environment, salinization and weathering, and in-situ resource extraction.

[0080] (5) Sample characteristic testing and verification

[0081] (5a) Dry pyrophyll simulants

[0082] Chemical elements: See Table 2. As can be seen from Table 2, the dry fire soil simulant prepared in this embodiment has a similar chemical composition content to the Martian in-situ regolith.

[0083] Table 2. Chemical elements and their contents (wt%) in simulated volcanic soil

[0084]

[0085] Particle size distribution: Analysis was performed using an image / laser particle size analyzer, and the results deviated from the target gradation curve by less than ±10%.

[0086] Internal friction angle and cohesion: The sample was filled into the cylindrical mold by layer compaction to make a standard specimen for triaxial test, and a triaxial compression test was carried out (the confining pressure of the triaxial test was 25, 50 and 75 kPa to simulate the geostress conditions of the shallow cover layer of Mars). The stress and strain data were recorded during the test, and the physical and mechanical properties of each grade were calculated as shown in Table 3.

[0087] Table 3 Physical and mechanical properties of each grade of material

[0088]

[0089] (5b) Contains ice-fire soil simulants

[0090] To verify the thermophysical properties and mechanical stability of ice-containing samples, three groups of samples with ice contents of 5 wt.%, 10 wt.%, and 15 wt.% were selected and tested at negative temperatures.

[0091] Thermal properties: Specific heat and phase change characteristics were tested using differential scanning calorimetry (DSC).

[0092] Mechanical properties: The peak strength of the sample, measured using a temperature-controlled triaxial compression testing machine, was approximately 40% higher than that of the dry sample. Figure 4 The results show that the ice bridge structure significantly enhances the adhesion between particles.

[0093] (5c) Samples of volcanic soil containing secondary minerals

[0094] Based on real Mars sampling and landing site exploration data, mineral powders such as sulfate, magnetite, and hematite can be added to dry Martian soil samples as needed (Table 4).

[0095] Table 4 Mineral composition of Martian soil and its analogues

[0096]

[0097] Test results show that simulated Martian soil samples prepared for different characteristics can well reproduce the real Martian soil characteristics in terms of chemical composition, physical properties, and mechanics. Diverse mechanical conditions can be achieved by adjusting the particle size distribution. The cohesion between sample particles can be significantly enhanced by adjusting different ice contents and ice states. Adding different proportions of secondary minerals can simulate the acidic or saline weathering environment of Mars in terms of chemical composition and mineral structure. This invention can provide a reliable material basis and experimental support for simulating the physical environment of the Martian surface, lander landing and obstacle-crossing tests, in-situ sampling, and resource utilization research.

[0098] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A method for preparing Martian regolith simulators with different characteristics, characterized in that, Includes the following steps: S1. Identify the raw materials based on the chemical elemental composition characteristics of the Martian regolith, and then dry the raw materials. S2. The dried raw material is placed in a planetary ball mill for multi-stage ball milling and pulverization, and then classified and screened to obtain particles of different particle size ranges and sealed for storage. S3. Based on the in-situ particle size distribution curve of Mars, design the gradation of different Martian regolith simulated materials; S4. According to the gradation of the Martian regolith simulator, mix particles of different size ranges in proportion to obtain a dry Martian regolith simulator. S5. Introduce pure water or salt solution into the dry Martian regolith simulator, mix them evenly, and freeze them at low temperature to form a stable ice-containing structure, thus obtaining an ice-containing Martian regolith simulator. S6. Introduce secondary minerals into the dry Martian regolith simulator and stir evenly under constant temperature conditions to obtain a Martian regolith simulator containing secondary minerals. In step S1, the raw material includes brownish-red natural volcanic rock, the oxide composition of which includes SiO2, Fe2O3, Al2O3, MgO, and CaO, and the mineral composition includes pyroxene, plagioclase, and olivine. In step S1, the drying process refers to drying continuously at a drying temperature of 105℃-110℃ for 5-8 hours. The drying is considered complete when the change in the mass of the raw material is less than 0.1wt.%. In step S2, the particle size range includes four types, specifically 0.5-2.5 mm, 0.25-0.5 mm, 0.075-0.25 mm, and 0-0.075 mm; Step S2 includes the following specific steps: S2.1 First, a four-tank high-speed planetary ball mill is used to perform multi-stage ball milling on the dried raw materials. By controlling different combinations of rotation speed and ball milling time parameters, particles with different particle size characteristics are prepared. Specifically: using a rotation speed of 300 rpm and a grinding time of 10 minutes, coarse particles of 2-5 mm are obtained; using a rotation speed of 400 rpm and a grinding time of 20 minutes, medium-coarse particles of 0.5-2 mm are obtained; using a rotation speed of 400 rpm and a grinding time of 30 minutes, relatively fine particles of 0.1-0.5 mm are obtained; using a rotation speed of 500 rpm and a grinding time of 35-40 minutes, extremely fine particles with a particle size of <0.1 mm are obtained. S2.2 The particles obtained after ball milling are vibrated and sieved using a combination of sieves with apertures of 2.5 mm, 0.5 mm, 0.25 mm and 0.075 mm respectively. Ultrafine particles with a particle size less than 0.075 mm are sieved using ultrasonic sieving to finally obtain particles in the four particle size ranges. In step S3, the Martian regolith gradation includes at least three types: Gradient 1: 22 wt.% of particles in the range of 0.5-2.5 mm with an allowable error of ±3%; 26 wt.% of particles in the range of 0.25-0.5 mm with an allowable error of ±3%; 32 wt.% of particles in the range of 0.075-0.25 mm with an allowable error of ±3%; and 20 wt.% of particles in the range of 0-0.075 mm with an allowable error of ±3%. The internal friction angle of gradation 1 is 20°-30°. Grade 2: 34 wt.% of particles in the range of 0.5-2.5 mm with an allowable error of ±3%, 47 wt.% of particles in the range of 0.25-0.5 mm with an allowable error of ±3%, 11 wt.% of particles in the range of 0.075-0.25 mm with an allowable error of ±3%, and 8 wt.% of particles in the range of 0-0.075 mm with an allowable error of ±3%; the internal friction angle of grade 2 is 30°-40°; Grade 3: 86 wt.% of particles in the range of 0.5-2.5 mm with an allowable error of ±3%, 9 wt.% of particles in the range of 0.25-0.5 mm with an allowable error of ±3%, 4 wt.% of particles in the range of 0.075-0.25 mm with an allowable error of ±3%, and 1 wt.% of particles in the range of 0-0.075 mm with an allowable error of ±3%; the internal friction angle of grade 3 is 40°-45°; In step S4, the obtained dry Martian regolith simulator is subjected to mechanical property tests, which include at least internal friction angle and cohesion tests. The measured values ​​of the mechanical properties are compared with the target indicators. If the measured values ​​deviate from the target indicators, the mixing ratio of particles in different particle size ranges is adjusted to correct the deviation until the mechanical properties of the dry Martian regolith simulator meet the target indicators.

2. The method for preparing Martian regolith simulators with different characteristics according to claim 1, characterized in that, In step S5, the salt solution includes either MgSO4 or NaCl aqueous solution, the low temperature condition refers to being equal to or below -20°C, and the ice content of the ice-containing Martian regolith simulator is 0.5-20 wt.%.

3. The method for preparing Martian regolith simulators with different characteristics according to claim 1, characterized in that, In step S6, the secondary minerals include any one or more of sulfates, carbonates, chlorides, magnetite, and hematite. The total proportion of secondary minerals in the Martian regolith simulator containing secondary minerals does not exceed 20 wt.%. The secondary minerals refer to secondary mineral powder. The constant temperature condition refers to 22-27℃.

4. The method for preparing Martian regolith simulators with different characteristics according to claim 1, characterized in that, In step S5, the internal friction angle and ice crystal size of the obtained ice-containing Martian regolith simulator are tested. The measured values ​​of ice content and ice crystal size are compared with the corresponding target indicators. If the measured value of ice content deviates from the target indicator, the water content of the simulator is adjusted by adjusting the amount of pure water or salt solution introduced into the dry Martian regolith simulator until the target indicator is reached. If the measured value of ice crystal size deviates from the target indicator, the uniform mixing and freezing time are adjusted until the target indicator is reached.

5. The method for preparing Martian regolith simulators with different characteristics according to claim 1, characterized in that, In step S6, the chemical composition of the obtained Martian regolith simulation containing secondary minerals is tested. The measured chemical composition results are compared with the target index. If the measured results deviate from the target index, the type and proportion of the introduced secondary minerals are adjusted to correct the chemical composition until it meets the target index.

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