A method for preparing sampled simulated lunar soil

Abstract

The present invention discloses a method for preparing sampled simulated lunar soil, including determining the raw material composition of the sampled simulated lunar soil, wherein the raw materials include light raw materials and main raw materials; processing the main raw materials into particles of different particle size ranges, and determining the gradation of the sampled simulated lunar soil; mixing fine particles of different particle size ranges according to the gradation of the sampled simulated lunar soil, and laying coarse particles in the depth direction to form the main mixed particles of the sampled simulated lunar soil; using the main mixed particles to obtain a block-shaped simulated lunar soil with an expected dense state; horizontally or vertically splicing the block-shaped simulated lunar soil to obtain a simulated lunar soil body; laying a light raw material for simulating the lunar gravity field on the surface of the simulated lunar soil body, and performing surface morphology construction to obtain the sampled simulated lunar soil. The preparation method of the present invention is flexible and can achieve envelope coverage of various states of the lunar soil.

Description

Technical Field

[0001] The present invention belongs to the field of space exploration technology, and in particular relates to a method for preparing simulated lunar soil for lunar surface sampling. Background Art

[0002] With the implementation of my country's lunar exploration project, relevant domestic scientific research institutions and universities have carried out a series of research on simulated lunar soil. The CAS-1 and CLRS series of simulated lunar soils are mainly for the purpose of serving scientific research, and the TYII, TJ, and LBD series of simulated lunar soils are mainly for the landing of landers and the movement of rover. The lunar soil simulants for lunar sampling activities should take into account the differences in the lunar soil states in different areas and depth profiles of the lunar surface. The objects of sampling activities have certain uncertainties, and the sampled simulated lunar soil should have certain volatility. At present, our understanding of lunar soil is still insufficient, and the impact of lunar soil on surface and deep sampling activities is still unclear. Related research work is still an important support for the lunar exploration mission, so it is urgent to realize flexible and compatible simulated lunar soil for sampling activities. Summary of the invention

[0003] The purpose of the present invention is to overcome the above-mentioned defects and provide a method for preparing lunar soil for sampling simulation, which solves the technical problems that the influencing factors of lunar sampling activities in the existing lunar soil simulation process are insufficiently considered and the flexibility and compatibility are not strong. The preparation method of the present invention is flexible and can meet the simulation requirements of various sampling tasks.

[0004] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0005] A method for preparing sampled simulated lunar soil, comprising:

[0006] Determine the raw material composition of the sampled simulated lunar soil, the raw materials including light raw materials and main raw materials;

[0007] Processing the main raw materials into particles of different particle size ranges, and determining the gradation of the sampled simulated lunar soil; among the particles of different particle size ranges, particles with a particle size range of less than 40 mm are regarded as fine particles, and particles with a particle size range of ≥ 40 mm are regarded as coarse particles;

[0008] According to the gradation of the sampled simulated lunar soil, fine particles of different particle size ranges are mixed, and coarse particles are laid in the depth direction to form the main mixed particles of the sampled simulated lunar soil;

[0009] Using the main mixed particles, a block-shaped simulated lunar soil with an expected dense state is obtained;

[0010] Splicing blocks of simulated lunar soil horizontally or vertically to obtain a main body of simulated lunar soil;

[0011] Lightweight raw materials used to simulate the lunar gravity field are laid on the main surface of the simulated lunar soil, and surface morphology is constructed to obtain sampled simulated lunar soil.

[0012] Furthermore, the raw material composition of the simulated lunar soil is determined according to the sampling task. Among them, light pumice is used as the light raw material; when the sampling task is lunar sea sampling, basalt or basaltic volcanic slag is used as the main raw material; when the sampling task is lunar land sampling, calcium-rich calcium feldspar or plagioclase is used as the main raw material, and the particle density of the main raw material is 2.9g / cm 3 ~3.5g / cm 3 The particle density of the light raw material is 0.45g / cm 3 ~0.65g / cm 3 ;

[0013] When the main raw material is processed into particles of different particle size ranges, the particle shape is angular or sub-angular; the moisture content of the particles is determined according to the sampling task. When the sampling task is a sampling task outside the lunar polar circle, the mass percentage of moisture in the sampled simulated lunar soil raw material is ≤1%; when the sampling task is a sampling task within the lunar polar circle, the mass percentage of moisture in the sampled simulated lunar soil raw material is 5% to 10%.

[0014] Furthermore, the specific method for determining the gradation of the sampled simulated lunar soil is:

[0015] Nominal simulated lunar soil selection gradation I;

[0016] Challenge to simulate lunar soil and select at least one of the grades II to VI;

[0017] The extreme simulated lunar soil for deep sampling is selected from at least one of the gradations I, III and VII;

[0018] The extreme simulated lunar soil sampled from the surface layer is selected from at least one of the grades II to VI;

[0019] The gradations I to VII are shown in the following table:

[0020] Particle size range Gradation I Gradation II Grade III Grade IV Grade V Gradation VI Grade VII Tolerance <1mm 85.00％ 65.80％ 78.16％ 85.04％ 81.22％ 95.28％ 59.37％ 4％ 1~2mm 5.00％ 6.90％ 7.76％ 3.21％ 2.42％ 2.23％ 10.00％ 0.25％ 2~4mm 3.50％ 10.35％ 4.67％ 2.49％ 1.82％ 0.80％ 10.00％ 0.25％ 4~10mm 3.50％ 11.43％ 5.11％ 1.85％ 2.17％ 1.14％ 10.00％ 0.25％ 10~40mm 3.00％ 5.52％ 4.30％ 7.41％ 12.37％ 0.55％ 10.63％ 0.25％ .

[0021] Further, the method of laying coarse particles in the depth direction is:

[0022] When subsurface detection data exists, coarse particles of 40 mm to 100 mm and larger than 100 mm are laid in the depth direction according to the subsurface detection data;

[0023] When sub-surface detection data is missing, coarse particles of 40mm to 100mm and larger than 100mm are laid in the depth direction according to statistical rules. Within every meter of depth, 0 to 2 particles with a diameter of 80mm to 110mm appear.

[0024] Furthermore, the blocks of simulated lunar soil are spliced ​​horizontally or vertically according to different sampling tasks;

[0025] For the surface sampling mission, the blocks of simulated lunar soil are horizontally spliced;

[0026] For the longitudinal sampling task, the blocks of simulated lunar soil are spliced ​​vertically.

[0027] Furthermore, the main mixed particles are used to obtain a block-shaped simulated lunar soil with a desired dense state by adopting a multi-directional vibration compaction device;

[0028] The multi-directional vibration compaction device includes a hoisting facility, a compaction block, a container and a vibration mechanism; the main mixed particles are placed in the container, the hoisting facility hoists the compaction block above the container, the compaction block is used to press down the main mixed particles placed in the container by its own weight, and the vibration mechanism is arranged below and on both sides of the container;

[0029] In the process of using a multi-directional vibration compaction device to obtain a block of simulated lunar soil with an expected dense state, the vibration time and vibration frequency of the vibration mechanism are controlled by monitoring the volume change of the main mixed particles.

[0030] Furthermore, the expected density states of the sampled simulated lunar soil include generally dense, moderately dense, or extremely dense;

[0031] Generally, the relative density of the densely sampled simulated lunar soil is 65% ± 3%;

[0032] The relative density of the simulated lunar soil of the medium-dense sampling is 85%±3%;

[0033] The relative density of the extremely dense sampling simulated lunar soil is 95%±3%.

[0034] Furthermore, when laying lightweight raw materials for simulating the lunar gravity field on the surface of the simulated lunar soil body, the particle size of the lightweight raw materials is 40 mm to 100 mm;

[0035] Lightweight materials are laid either buried or floating.

[0036] Further, the method for performing surface topography construction is:

[0037] When surface topography image information exists, surface topography is constructed according to the surface topography image information;

[0038] When the surface topography image information is missing, the surface topography is constructed according to statistical laws;

[0039] When constructing the surface topography according to the surface topography image information, firstly, the plane of the flattened sampling area is fitted and the normal vector of the plane of the flattened sampling area is determined, the surface slope and slope direction are obtained according to the normal vector of the plane of the flattened sampling area, and the slope surface is constructed on the plane of the flattened sampling area according to the surface slope and slope direction;

[0040] When constructing the surface morphology according to statistical laws, there are no less than 10 pits with a diameter greater than 100 mm per square meter of surface, and 0 to 2 pits with a diameter greater than 300 mm; there are 0 to 2 lightweight raw material particles of 80 to 110 mm per square meter of surface;

[0041] When performing surface topography construction, the slope of the slope is not greater than 8°, and the slope direction varies within the range of 0° to 360°.

[0042] Furthermore, the above-mentioned method for preparing the sampled simulated lunar soil further includes:

[0043] After the sampling test is completed, the repeatability of the sampled simulated lunar soil is evaluated. The specific method is: when the surface area of ​​the undisturbed sampled simulated lunar soil is more than 10 times the diameter of the deep sampling drill or more than 3 times the scale of the surface sampler, the sampled simulated lunar soil is repeatable.

[0044] When the sampled simulated lunar soil is reproducible, it will be used for the next sampling test;

[0045] When the sampled simulated lunar soil is not repeatable, if the gradation of the sampled simulated lunar soil used in the next sampling test is the same as that in this sampling test, the sampled simulated lunar soil of this sampling test will be directly used to prepare the block simulated lunar soil for the next sampling test; if the gradation of the sampled simulated lunar soil used in the next sampling test is different from that in this sampling test, the sampled simulated lunar soil of this sampling test will be sieved and classified according to the particle size range and then mixed again according to the gradation.

[0046] Compared with the prior art, the present invention has the following beneficial effects:

[0047] (1) The present invention creatively proposes a method for preparing simulated lunar soil for sampling, which can flexibly prepare simulated lunar soil for lunar surface sampling according to the requirements of the sampling mission, and prepare customizable nominal, challenge and extreme simulated lunar soils through quantitative parameter control;

[0048] (2) The present invention proposes a material constraint method for lunar soil simulation to ensure the controllability and stability of the performance of the sampled simulated lunar soil;

[0049] (3) The present invention proposes a mixing method for simulating lunar soil samples, and in particular provides a series of typical gradations to achieve envelope coverage of typical states of lunar soil in the surface and deep layers;

[0050] (4) The present invention proposes a forming equivalent method for lunar sampling and lunar soil simulation, which covers the effects of lunar surface morphology and low gravity environment on surface sampling and deep sampling;

[0051] (5) The present invention provides a basis for sampling test evaluation and lunar soil comparative research by controlling the raw materials, mixing and forming parameters of lunar sampling simulated lunar soil and evaluating the simulated lunar soil before and after the sampling test. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 This is a schematic diagram of the process of preparing the sampled simulated lunar soil in the present invention;

[0053] Figure 2 A schematic diagram of vibration compaction of sampling simulated lunar soil in the present invention;

[0054] Figure 3 Schematic diagram of the reference distribution of (a) impact craters and (b) rock blocks on the lunar surface in the present invention. DETAILED DESCRIPTION

[0055] The following detailed description of the present invention will make the features and advantages of the present invention more clear and explicit.

[0056] The word "exemplary" is used exclusively herein to mean "serving as an example, embodiment, or illustration." Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments. Although various aspects of the embodiments are shown in the drawings, the drawings are not necessarily drawn to scale unless otherwise noted.

[0057] The present invention is based on the research and development of sampling simulated lunar soil in my country, and aims at the demand for flexible preparation of lunar surface sampling simulated lunar soil. It proposes raw material control requirements for sampling simulated lunar soil from the aspects of material, particle morphology, particle density, particle size range, and water content. For the preparation process of simulated lunar soil, it proposes grading control requirements for sampling simulated lunar soil with a certain envelope range. It also proposes structural control requirements for sampling simulated lunar soil by comprehensively considering relative density, topography, profile distribution, and low gravity field. Based on the characteristic parameters, it standardizes the preparation method of lunar surface sampling simulated lunar soil.

[0058] The method for preparing simulated lunar soil for sampling proposed in the present invention is used for preparing simulated lunar soil for ground sampling, and the method comprises the following steps: step one, selection of substrate for simulated lunar soil for sampling, selecting a specific substrate in combination with mission objectives and environmental characteristics, and determining the material composition and density of surface or deep simulated lunar soil particles for sampling; step two, generation of particle size and morphology of simulated lunar soil for sampling, processing the selected substrate according to the particle size envelope range and main morphology of the lunar soil, and generating required raw material particles of different sizes and specific morphologies; step three, control of moisture content of simulated lunar soil for sampling, processing and controlling the moisture content of raw material particles in combination with the characteristics of the sampling object and the verification content of the sampling mechanism, and forming simulated raw materials with different humidity; step four, gradation control of simulated lunar soil for sampling, combining the requirements of experimental verification working conditions, using simulated raw materials of specific particle sizes for combination and preparation according to a certain content, and grading the coarse particles of simulated lunar soil for sampling as needed. For distributed laying, rock-like particles of specific shape, size and position need to be laid along the depth direction (deep sampling) or in the regional range (surface sampling); step five, relative density control of sampled simulated lunar soil, according to the requirements of ground sampling test conditions, the density control of sampled simulated lunar soil is achieved through the vibration process; step six, morphology and structure of sampled simulated lunar soil, according to the morphology characteristics of the lunar surface, specific slopes, impact craters and other deployments are carried out on the basis of existing sampled simulated lunar soil; step seven, low gravity equivalence of sampled simulated lunar soil surface, the characteristics of surface lunar soil under the low gravity field of the moon are simulated through lightweight simulants; step eight, status evaluation of sampled simulated lunar soil, before the sampling test, local sampling of simulated lunar soil can be carried out in the container, basic characteristic compliance determination can be carried out, and in-situ mechanical properties can be measured to form a sampling object with clear characteristics. After the sampling test, the repeatability of the simulated lunar soil can be evaluated.

[0059] In the present invention, during the preparation of the sampled simulated lunar soil, the sampled simulated lunar soil construction process is differentially controlled mainly from the aspects of substrate, form, particle size, water content, ratio, relative density, morphology, gravity influence, etc., and the mechanical properties are evaluated before the test. For lunar surface sampling activities, different sampled simulated lunar soils containing the above characteristics are divided into three categories: nominal simulated lunar soil, challenge simulated lunar soil and extreme simulated lunar soil. In the specific implementation process, the control parameters of nominal, challenge and extreme simulated lunar soils can be adjusted according to the differences in sampling methods.

[0060] Specifically, in step one, the following is performed: based on the differences in the lunar regolith in different regions of the moon and in combination with the differences in the gravity fields of the earth and the moon, a comprehensive analysis is conducted on various soil and rock materials in the earth's environment, the main types of substrates for sampling simulated lunar soil are determined, and the particle density of the raw materials is measured to meet the needs of surface sampling and deep sampling.

[0061] Furthermore, in step 2, the following is performed: the selected materials are segmented, ground, screened, etc. according to the morphological requirements and particle size range. The particle size and morphological processing of the particles need to be comprehensively considered and prepared simultaneously. After processing, the raw material particles need to be classified, stored and labeled according to a certain particle size fluctuation range and particle size morphology differences.

[0062] Furthermore, in step three, the following is performed: based on the location and characteristic differences of the lunar sampling target area, the moisture content requirement of the raw material particles is determined, the raw material is dried or humidified, and measurements are required before and after the moisture content treatment.

[0063] Furthermore, in step four, the following is performed: according to the selected sampling simulated lunar soil raw materials, combined with the sampling activities or working conditions, the preparation process is controlled according to the coarseness and fineness of the particle size. When there are clear given grading requirements, mixing and balancing can be performed as required. When there are no clear grading requirements, selection can be made from typical gradings to prepare nominal, challenging and extreme simulated lunar soils. Depending on the different objects of the sampling mission, the sampling simulated lunar soil grading process should carry out differential control of special coarse particles. Combined with the detection data of scientific instruments, the coarse particles are deployed on the depth profile according to a certain distribution, and the mutation characteristics caused by the coarse particles in the sampling activities are simulated. The distribution control of coarse particles can be laid by random distribution of shape, size, and position or by specified distribution.

[0064] Furthermore, in step five, the following is performed: on the basis of fine particle grading control and coarse particle dispersion and laying, the simulated raw materials in a loose state are vibrated and compacted by a vibration device, and the relative density of the sampled simulated lunar soil is indirectly controlled through a quantitative volume control scheme. For deep-layer sampled simulated lunar soil, the control targets of different layers and different relative densities can be achieved by using segmented vibration and multi-segment assembly; for surface-layer sampled simulated lunar soil, the control targets of different partitions and different relative densities can be achieved by using partitioned vibration and module assembly.

[0065] Furthermore, in step six, the following is performed: the morphological differences in the sampling area will affect the movement path and sampling method of the sampling equipment, and may affect the safety of the sampling activities. According to the lunar surface images and morphological detection data, combined with the structural size relationships such as the slope and direction of the lunar surface, protrusions or pits, etc., a typical sampling area morphology is constructed.

[0066] Further, in step seven, the following is performed: for surface sampling activities, due to the influence of low gravity on the lunar surface, the regolith in the weathered layer has stronger fluidity than that on the ground, and lightweight simulants are used to simulate the coarse surface particles. Generally, particles with a diameter of more than 40 mm can be selected for simulation. The specific boundary scale of the coarse particles can be determined according to the scale of the sampling equipment to better reflect the interaction process between the sampling equipment and the coarse surface particles.

[0067] Furthermore, in step eight, the following is performed: the sampled simulated lunar soil prepared by raw material control, mixing control and forming control is generally contained in a specific container, and the sampled simulated lunar soil can be sampled on site by a portable soil sampler, moisture meter, etc., and the basic characteristics such as particle morphology, gradation, relative density, and moisture content after preparation are measured to check whether the prepared simulated lunar soil meets the requirements. If the measuring instruments are available, the simulated lunar soil samples can be sampled to measure mechanical properties such as compression characteristics, bearing characteristics, and shear resistance. After the sampling test, the repeatability of the sampled simulated lunar soil that has completed a sampling test is analyzed in combination with the effectiveness of the sampled simulated lunar soil verification, the preparation time and manpower consumption, and the like, to determine the unloading, screening or storage workflow of the sampled simulated lunar soil after the test.

[0068] Example:

[0069] This embodiment provides a method for preparing lunar surface sampling simulated lunar soil, which is used for the preparation of sampling simulated lunar soil. The method mainly includes five aspects: raw material control, mixing control, forming control, state evaluation and repeated application, especially the sampling simulated lunar soil raw material control method based on substrate selection, particle size and morphology generation, and moisture content control; the flexible preparation method of layered or partitioned multi-gradation simulated lunar soil based on gradation control and relative density control; and the sampling simulation forming control method based on the lunar surface morphology and gravity influence. A typical sampling simulated lunar soil preparation process is as follows: Figure 1 As shown, the specific implementation process of the sampling simulated lunar soil preparation control method of the present invention is as follows:

[0070] Basalt or basaltic volcanic slag is used as the base material for lunar soil simulation of lunar sea sampling. Basalt is used as the raw material for particles with a particle size of more than 1mm, and basalt or basaltic volcanic slag can be used for particles with a particle size of less than 1mm. Calcium-rich calcium feldspar or plagioclase is used as the base material for lunar soil simulation of lunar land sampling. Light pumice is used as the base material for low-gravity simulation of lunar soil sampling. The density of non-light raw material particles for sampling simulated lunar soil is generally 2.9g / cm 3 ~3.5g / cm 3 The density of lightweight raw material particles is generally 0.45g / cm 3 ~0.65g / cm 3 , lightweight raw materials can be used to simulate the lunar surface regolith, which is easy to flow under the low gravity.

[0071] The morphology of the sampled simulated lunar soil materials should be angular and sub-angular, and the recommended particle aspect ratio is between 1.3 and 1.4. According to the difference in particle size, the sampled simulated lunar soil materials are divided into 7 subcategories as shown in Table 1. According to the different sampling activities and test conditions, the influence of fine particles and coarse particles is comprehensively considered. For scenes that require fine simulation, the recommended subdivision range in Table 1 can be referred to for further subdivision. Particles with a diameter less than 10μm or rocks larger than 300mm are no longer distinguished.

[0072] Table 1 Particle size classification of sampled simulated lunar soil materials

[0073]

[0074] The moisture content of the sampled simulated lunar soil materials needs to be controlled according to the different lunar sampling areas. Generally, the water weight content of the sampled simulated lunar soil materials used for sampling exploration or sampling return missions outside the lunar polar circle should not exceed 1%; the water weight content of the sampled simulated lunar soil materials used for missions within the lunar polar circle (above 79° south latitude or above 86° north latitude) is greater than 5% and less than 10%, and appropriate adjustments can be made for specific needs.

[0075] During the grading process, different particle size simulants are mixed according to a certain volume ratio or mass ratio, and a specific stirring device is used for equalization. The main part of the sampled simulated lunar soil is formed by mixing fine particles with coarse particles. The typical particle size ratio of fine particles in the mixing process is shown in Table 2 (mass percentage). While referring to the typical particle size ratio, the coarse particles can be set at a specific position on the surface or subsurface according to a certain profile distribution during the mixing process based on the lunar surface morphology or subsurface detection data.

[0076] Table 2 Typical particle size ratios of sampled simulated lunar soil

[0077]

[0078] Normally, the nominal simulated lunar soil can choose gradation I as the ratio, the challenging simulated lunar soil can choose gradation II~VI as the ratio, the extreme simulated lunar soil for deep sampling can choose gradation I, III and VII as the ratio, and the extreme simulated lunar soil for surface sampling can choose gradation II~VI as the ratio. For complex working conditions, a variety of gradation combinations can be used to achieve layered or zoned multi-gradation simulated lunar soil. Generally, deeper layers should use gradation types with a higher proportion of coarse particles. During the mixing process of sampling simulated lunar soil, the distribution of larger particles in non-surface layers must be paid special attention. Considering that the isotropic distribution of rock blocks in the simulated lunar soil is approximately isotropic, particles of 40mm~100mm and larger than 100mm can be laid in the depth direction according to the sub-surface detection data. When sub-surface detection information is missing, the distribution of rock blocks in the depth direction can be as follows Figure 3The laying is carried out according to the statistical law shown in the figure. Generally, within each meter of depth, there are no less than 50 particles with a diameter greater than 40 mm and 0 to 2 rock blocks with a diameter of 80 mm to 110 mm.

[0079] The sampled simulated lunar soil may have different relative densities (lateral changes) at different locations in the sampling area, and may also have different relative densities (vertical changes) at different sampling depths. For surface sampling tasks, the relative density changes are mainly reflected in lateral changes, and a partitioning construction scheme can be used to achieve different relative density requirements for each block; for deep sampling tasks, the relative density changes are mainly reflected in longitudinal changes, and a layered preparation scheme can be used to achieve different relative density requirements for each layer in the depth direction. Therefore, the sampling simulated lunar soil construction process is the process of horizontally or vertically splicing a series of block simulated lunar soils or layered simulated lunar soils with different relative densities. The block simulated lunar soil or layered simulated lunar soil is compacted by vibration to obtain the required relative density. Vibration compaction has a variety of schemes. A multi-directional vibration compaction device such as Figure 2 As shown, the hoisting facility 1, the compaction block 2, the container 3 and the vibration table (including the lower vibration table 4, the left vibration table 5 and the right vibration table 6) are combined from top to bottom, and transverse plane vibrators are installed on the left and right sides of the container, specifically including the first vibrator 7, the second vibrator 8, and the third vibrator 9. The simulated raw materials are added (or coarse particles are laid) into the container. Before vibration, the top of the container is sealed by the pressing block and its weight is used to apply downward pressure. The vibrator is started to vibrate the left, right and bottom to realize the transformation of the simulated lunar soil from a loose state to a dense state. The relative density of the sampled simulated lunar soil is monitored by the volume change of the block or layered simulated lunar soil during the vibration compaction process, and the dense state (generally dense, medium dense or extremely dense) is controlled by the vibration time and frequency. It is recommended that the relative density of the typical general dense sampling simulated lunar soil be controlled at 65%±3%, the relative density of the typical medium dense sampling simulated lunar soil be 85%±3%, and the relative density of 95%±3% be the typical extremely dense simulated lunar soil.

[0080] During the formation of lunar soil, the morphology of the sampling area can be constructed based on the downlinked sampling area image or the reconstructed digital terrain to determine the slope, aspect, ridges or pits. Figure 3The layout is based on the relationship shown in the figure. Generally, for the local area involved in the sampling, there are no less than 10 pits with a diameter greater than 100 mm per square meter, and 0 to 2 pits with a diameter greater than 300 mm; generally, there are 0 to 2 rock blocks with a diameter of 80 mm to 110 mm per square meter. In the process of morphological construction, the flat sampling area plane with the most coincidence points with the morphological information (generally a three-dimensional digital model) is first fitted through the acquired morphological information, and its normal vector is determined, and then the slope and direction are obtained. The flat plane with a certain slope and a specific slope direction can be constructed. The slope is generally not greater than 8°, and the slope direction can vary within the range of 0° to 360°. The fitted flat sampling area plane is used as the reference plane, and then the fixed-point construction of surface protrusions or pits is performed according to the digital terrain.

[0081] During the formation control process of the sampled simulated lunar soil, lightweight raw materials are laid on the surface of the sampled simulated lunar soil to simulate the 40mm to 100mm rock blocks distributed on the surface. Their dense state is loose, and no relative density control is performed. Since the protruding rocks may be partially buried under the lunar surface, while using lightweight simulants for low gravity equivalence, the lightweight rock blocks can be deployed in two ways: buried and floating.

[0082] Different sampling tasks can be implemented by different sampling simulated lunar soil states. In the process of sampling simulated lunar soil construction, the influencing factors can be traded off according to the different surface sampling and deep sampling tasks. After the preparation of the sampled simulated lunar soil is completed, the simulated lunar soil in the container is sampled using a portable soil sampler to complete the determination of basic characteristics such as particle morphology, gradation, relative density, and water content after preparation to confirm whether the simulated lunar soil meets the requirements. If the measuring instrument is available, the mechanical properties such as compression characteristics, bearing characteristics, and shear resistance of the simulated lunar soil samples can be measured. After the sampling test is completed, the repeatability of the sampled simulated lunar soil can be evaluated. Generally, when the surface area of ​​the undisturbed sampled simulated lunar soil is more than 10 times the diameter of the deep sampling drill or more than 3 times the scale of the surface sampler, the sampled simulated lunar soil can be used again for deep sampling or surface sampling verification. When it can no longer be used for sampling tests, the simulated lunar soil in the container needs to be unloaded. If the same grading requirements are used in the re-test and there are no special requirements, it is recommended to skip the previous sequence and directly enter the relative density control process to prepare the sampling simulated lunar soil; if the grading changes in the re-test, the used simulated lunar soil needs to be screened, recombined with new raw material particles, and then enter the mixing control process to prepare the sampling simulated lunar soil; when the screened raw materials are not available in the next sampling test, it is recommended to use well-sealed containers for storage, and classify and mark the particle size for use in other working conditions for sampling simulated lunar soil preparation.

[0083] The present invention has been described in detail above in conjunction with specific implementations and exemplary examples, but these descriptions cannot be understood as limiting the present invention. Those skilled in the art understand that, without departing from the spirit and scope of the present invention, a variety of equivalent substitutions, modifications or improvements may be made to the technical solution of the present invention and its implementation methods, all of which fall within the scope of the present invention. The scope of protection of the present invention shall be subject to the attached claims.

[0084] The contents not described in detail in the specification of the present invention belong to the common knowledge of those skilled in the art.

Claims

1. A method for preparing sampled simulated lunar soil, characterized in that: include: Determine the raw material composition of the sampled simulated lunar soil, the raw materials including light raw materials and main raw materials; Processing the main raw materials into particles of different particle size ranges, and determining the gradation of the sampled simulated lunar soil; among the particles of different particle size ranges, particles with a particle size range of ≤40 mm are regarded as fine particles, and particles with a particle size range of >40 mm are regarded as coarse particles; According to the gradation of the sampled simulated lunar soil, fine particles of different particle size ranges are mixed, and coarse particles are laid in the depth direction to form the main mixed particles of the sampled simulated lunar soil; Using the main mixed particles, a block-shaped simulated lunar soil with an expected dense state is obtained; Splicing blocks of simulated lunar soil horizontally or vertically to obtain a main body of simulated lunar soil; Laying lightweight raw materials for simulating the lunar gravity field on the main surface of the simulated lunar soil, and performing surface morphology construction to obtain sampled simulated lunar soil; The raw material composition of the simulated lunar soil is determined according to the sampling task. Among them, light pumice is used as the light raw material; when the sampling task is lunar sea sampling, basalt or basaltic volcanic slag is used as the main raw material; when the sampling task is lunar land sampling, calcium-rich calcium feldspar or plagioclase is used as the main raw material, and the particle density of the main raw material is 2.9g / cm 3 ~3.5g / cm 3 The particle density of the light raw material is 0.45g / cm 3 ~0.65g / cm 3 ; When the main raw material is processed into particles of different particle size ranges, the particle shape is angular or sub-angular; the moisture content of the particles is determined according to the sampling task. When the sampling task is a sampling task outside the lunar polar circle, the mass percentage of moisture in the sampled simulated lunar soil raw material is ≤1%; when the sampling task is a sampling task within the lunar polar circle, the mass percentage of moisture in the sampled simulated lunar soil raw material is 5% to 10%; The specific method for determining the gradation of sampled simulated lunar soil is: Nominal simulated lunar soil selection gradation I; Challenge to simulate lunar soil and select at least one of the grades II to VI; The extreme simulated lunar soil for deep sampling is selected from at least one of the gradations I, III and VII; The extreme simulated lunar soil sampled from the surface layer is selected from at least one of the grades II to VI; The gradations I to VII are shown in the following table: 。 2. The method for preparing sampled simulated lunar soil according to claim 1, characterized in that: The method of laying coarse particles in the depth direction is: When subsurface detection data exists, coarse particles with a diameter of 40 mm to 100 mm and a diameter greater than 100 mm are laid in the depth direction according to the subsurface detection data; When sub-surface detection data is missing, coarse particles of 40mm to 100mm and larger than 100mm are laid in the depth direction according to statistical rules. Within every meter of depth, the number of particles with a diameter larger than 40mm is no less than 50, and the number of particles with a diameter of 80-110mm is 0-2.

3. The method for preparing sampled simulated lunar soil according to claim 1, characterized in that: According to different sampling tasks, the blocks of simulated lunar soil are spliced ​​horizontally or vertically; For the surface sampling mission, the blocks of simulated lunar soil are horizontally spliced; For the longitudinal sampling task, the blocks of simulated lunar soil are spliced ​​vertically.

4. The method for preparing sampled simulated lunar soil according to claim 1, characterized in that: Using the main mixed particles, a multi-directional vibration compaction device is used to obtain a block of simulated lunar soil with an expected dense state; The multi-directional vibration compaction device includes a hoisting facility, a compaction block, a container and a vibration mechanism; the main mixed particles are placed in the container, the hoisting facility hoists the compaction block above the container, the compaction block is used to press down the main mixed particles placed in the container by its own weight, and the vibration mechanism is arranged below and on both sides of the container; In the process of using a multi-directional vibration compaction device to obtain a block of simulated lunar soil with an expected dense state, the vibration time and vibration frequency of the vibration mechanism are controlled by monitoring the volume change of the main mixed particles.

5. The method for preparing sampled simulated lunar soil according to claim 1, characterized in that: The expected compaction states of the sampled simulated lunar soil include generally dense, moderately dense or extremely dense; Generally, the relative density of the densely sampled simulated lunar soil is 65% ± 3%; The relative density of the simulated lunar soil of the medium-dense sampling is 85%±3%; The relative density of the extremely dense sampling simulated lunar soil is 95%±3%.

6. The method for preparing sampled simulated lunar soil according to claim 1, characterized in that: When laying lightweight raw materials for simulating the lunar gravity field on the surface of the simulated lunar soil, the particle size of the lightweight raw materials is 40 mm to 100 mm; Lightweight materials are laid either buried or floating.

7. The method for preparing sampled simulated lunar soil according to claim 1, characterized in that: The method for surface topography is: When surface topography image information exists, surface topography is constructed according to the surface topography image information; When the surface topography image information is missing, the surface topography is constructed according to statistical laws; When constructing the surface topography according to the surface topography image information, firstly, the plane of the flattened sampling area is fitted and the normal vector of the plane of the flattened sampling area is determined, the surface slope and slope direction are obtained according to the normal vector of the plane of the flattened sampling area, and the slope surface is constructed on the plane of the flattened sampling area according to the surface slope and slope direction; When constructing the surface morphology according to statistical laws, there are no less than 10 pits with a diameter greater than 100 mm per square meter of surface, and 0 to 2 pits with a diameter greater than 300 mm; there are 0 to 2 lightweight raw material particles with a diameter of 80 mm to 110 mm per square meter of surface; When performing surface topography construction, the slope of the slope is not greater than 8°, and the slope direction varies within the range of 0° to 360°.

8. The method for preparing sampled simulated lunar soil according to claim 1, characterized in that: Also includes: After the sampling test is completed, the repeatability of the sampled simulated lunar soil is evaluated. The specific method is: when the surface area of ​​the undisturbed sampled simulated lunar soil is more than 10 times the diameter of the deep sampling drill or more than 3 times the scale of the surface sampler, the sampled simulated lunar soil is repeatable. When the sampled simulated lunar soil is reproducible, it will be used for the next sampling test; When the sampled simulated lunar soil is not repeatable, if the gradation of the sampled simulated lunar soil used in the next sampling test is the same as that in this sampling test, the sampled simulated lunar soil of this sampling test will be directly used to prepare the block simulated lunar soil for the next sampling test; if the gradation of the sampled simulated lunar soil used in the next sampling test is different from that in this sampling test, the sampled simulated lunar soil of this sampling test will be sieved and classified according to the particle size range and then mixed again according to the gradation.

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