Structure thermal control integrated design method for micro-nano satellite

Abstract

The invention relates to a micro-nano satellite-oriented structure thermal control integrated design method, which comprises the following steps of: firstly, comprehensively considering constraint conditions of a micro-nano satellite, including bearing force, size, quality, mechanical interface, external heat flow and internal heat source, and integrally designing a micro-nano satellite structure subsystem and a thermal control subsystem; designing the micro-nano satellite configuration and layout; a mechanical interface and a thermal interface of the micro-nano satellite are designed in parallel; designing a heat dissipation mode of the micro-nano satellite; and finally, designing a micro-nano satellite isothermal mode. Structural components of the micro-nano satellite are made of heat conduction materials, and thermal control coatings, surface treatment of structural parts, heat insulation gaskets and multiple layers of heat insulation materials are integrated, so that miniaturization and light weight of the micro-nano satellite are achieved, and thermal control efficiency and structural stability are improved. The method is suitable for efficient thermal control requirements of micro-nano satellites, the mass of the micro-nano satellites is remarkably reduced, and the in-orbit reliability of the micro-nano satellites is enhanced.

Description

Technical Field

[0001] The present invention belongs to the field of micro-nano satellites, and in particular relates to a structural thermal control integrated design method for micro-nano satellites. Background Art

[0002] With the continuous development of aerospace technology, micro-nano satellites have been widely used in scientific exploration, remote sensing, communications and other fields due to their small size, low cost and flexible and diverse missions. However, the structural and thermal control problems faced by micro-nano satellites in the design process are becoming more and more prominent. The structural design of micro-nano satellites must meet the mechanical bearing during the launch process and the stability of on-orbit operation, while the thermal control design needs to cope with the complex space thermal environment to ensure that the temperature of the satellite's internal equipment remains within the allowable range. However, due to the size and mass limitations of micro-nano satellites, their internal space is small, and it is often difficult to achieve efficient structural and thermal control design alone.

[0003] In traditional satellite design, structure and thermal control are generally designed and optimized as two independent subsystems. Although this method is more applicable in large satellite design, due to the strict constraints of size and mass in micro-nano satellite design, designing the two separately will lead to space waste and weight increase, which will easily complicate the design of micro-nano satellites, affect the reliability of the system, and make it difficult to achieve miniaturization, lightness and high efficiency of micro-nano satellites.

[0004] In the existing technology, heat sinks, heat pipes, shutters and other devices are usually used to control heat transfer, and active heating treatment is taken for temperature-sensitive units to improve thermal control performance. However, in micro-nano satellites, traditional thermal control methods and structural design methods are often unable to achieve efficient thermal control effects under limited size and mass constraints, resulting in the thermal control system occupying more space and energy, and increasing the overall mass of micro-nano satellites. In addition, micro-nano satellites are easily affected by temperature changes in the external environment during their in-orbit operation. How to design a system with efficient thermal control performance and structural strength within limited mass and space has become a major problem in the design of micro-nano satellites. Summary of the invention

[0005] The purpose of the present invention is to propose a structural thermal control integrated design method for micro-nano satellites. The method is based on the constraints of the micro-nano satellites in terms of load-bearing, size and mass, mechanical interface, thermal environment and energy utilization, and integrates the structural subsystem and thermal control subsystem of the micro-nano satellite. While ensuring that the micro-nano satellite has efficient thermal control performance, the miniaturization and lightweight of the micro-nano satellite are achieved, thereby improving the reliability and stability of the micro-nano satellite's in-orbit operation.

[0006] The technical solution to realize the present invention is: a structural thermal control integrated design method for micro-nano satellites, the steps are as follows:

[0007] Step 1: Comprehensively consider the input conditions of the micro-nano satellite, including load-bearing, size, mass, mechanical interface, external heat flow and internal heat source, and integrate the structural subsystem and thermal control subsystem;

[0008] Step 2: Design the micro-nano satellite configuration layout:

[0009] Consider the constraints of the thermal control subsystem on the layout and the implementation space of the thermal control products in the configuration and layout design to achieve the organic integration of the structural subsystem and the thermal control subsystem;

[0010] Step 3: Based on the interface input file, the mechanical interface and thermal interface of the micro-nano satellite are designed in parallel;

[0011] Step 4: Design the heat dissipation method of the micro-nano satellite, including the location of the heat dissipation surface and the size of the heat dissipation surface;

[0012] Step 5: Design the isothermalization method of the micro-nano satellite and integrate thermal control components into the micro-nano satellite structural subsystem, including thermal conductive materials, surface treatment of structural parts, thermal insulation gaskets, MLI and thermal conductive fillers to improve thermal control performance.

[0013] Compared with the prior art, the present invention has the following significant advantages:

[0014] (1) Reduced mass and improved reliability: The integrated design of the present invention not only reduces the overall mass of the micro-nano satellite and increases the payload ratio, but also improves the stability and reliability of on-orbit operation. It is particularly suitable for micro-nano satellite missions that require high thermal control efficiency.

[0015] (2) Optimizing the thermal control layout of high-power single machines: With regard to the layout of high-power single machines, the present invention comprehensively considers the thermal control requirements and rationally arranges the high-power single machines to ensure that these single machines have the best heat dissipation channels, thereby improving the temperature balance inside the micro-nano satellite and effectively avoiding local overheating.

[0016] (3) Integrate the main load-bearing structure, heat dissipation surface and isothermal treatment into one: By performing isothermal treatment on the surface of the main load-bearing structure and spraying a thermal control coating, the radiation heat dissipation performance of the main load-bearing structure is significantly improved, which can effectively manage the overall temperature of the micro-nano satellite, reduce the impact of external temperature fluctuations on the internal unit, and ensure the stability of the micro-nano satellite thermal control system.

[0017] (4) Modular design: The present invention designs the PCB support frame and the spacer as modular components. The modular components have both load-bearing and thermal control functions. The spacer material between the single units that need to be installed with heat conduction is a thermal conductive material. The single units that need to be installed with heat insulation only need to replace the spacer with a heat insulation material. This not only achieves the stability of the micro-nano satellite structure support, but also improves the thermal control efficiency, further reduces the overall mass of the micro-nano satellite while reducing the amount of materials used. It improves the flexibility of thermal design and reduces the complexity of traditional thermal control system design.

[0018] Reduce design iteration time: Mechanical and thermal input conditions are considered simultaneously during the design, and the structural subsystem and thermal control subsystem of the micro-nano satellite are designed in parallel. This reduces the multiple iterative designs caused by the separate design of the structural subsystem and the thermal control subsystem in traditional design, and effectively improves the design efficiency of the micro-nano satellite. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a flow chart of the micro-nano satellite structure thermal control integrated design method of the present invention.

[0020] Figure 2 It is a structural diagram of the micro-nano satellite separation mechanism used as an example in the present invention.

[0021] Figure 3 It is the overall design diagram of the micro-nano satellite used as an example in the present invention.

[0022] Figure 4 This is a structural diagram of a micro-nano satellite base plate according to an example of the present invention.

[0023] Figure 5 It is a modular design structure diagram of a micro-nano satellite according to an example of the present invention.

[0024] Figure 6 It is a structural diagram of the integrated shell of a micro-nano satellite according to an example of the present invention.

[0025] Figure 7 This is a diagram of the internal single-machine layout of a micro-nano satellite used as an example in the present invention. DETAILED DESCRIPTION

[0026] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] The technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on the fact that ordinary technicians in the field can implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0028] The following will further introduce the specific implementation method, as well as the technical difficulties and inventive points of this invention in combination with this design example.

[0029] Combination Figure 1 , a structural thermal control integrated design method for micro-nano satellites, the steps are as follows:

[0030] Step 1: Comprehensively consider the input conditions of the micro-nano satellite, including load-bearing, size, mass, mechanical interface, external heat flow and internal heat source, and conduct an integrated analysis of the structural subsystem and thermal control subsystem, as follows:

[0031] The load-bearing constraints of micro-nano satellites include: static load of separation mechanism, separation impact of separation mechanism, vibration fundamental frequency requirements, and static load deformation requirements.

[0032] The mechanical interface of the micro-nano satellite includes the following: the connection method between the micro-nano satellite and the separation mechanism, the connection point position of the separation mechanism in the input conditions, the material of the positioning pins at the connection point, the power supply method of the micro-nano satellite and the carrier satellite, the installation position of the travel switch, and the mechanical interface of the micro-nano satellite to other mechanisms.

[0033] The external heat flow of a micro-nano satellite requires comprehensive consideration of the orbit, attitude and thermal boundary conditions of the micro-nano satellite, and calculation of the magnitude of the heat flow of solar radiation, earth infrared radiation, and earth reflected radiation received by the external surfaces of the micro-nano satellite, as well as the heat flow impact of other spacecraft on the micro-nano satellite.

[0034] The orbital parameters of the micro-nano satellite include the orbital altitude, orbital inclination, and ascending node time; the attitude parameters of the micro-nano satellite include the overall coordinate system of the micro-nano satellite, the in-orbit flight direction, and the in-orbit direction to the earth; based on the flight attitude, the magnitude of the external heat flux incident on each surface of the micro-nano satellite in extreme high temperature conditions and extreme low temperature conditions is calculated, and then the position of the heat dissipation surface and the heat insulation surface of the micro-nano satellite are determined.

[0035] The size of the internal heat source of the micro-nano satellite and the operating temperature range of the internal single unit are important parameters that determine the overall temperature condition of the micro-nano satellite. The micro-nano satellite units are reasonably distributed according to the size of the internal heat source to avoid the concentration of high-power single units; the temperature gradient of the micro-nano satellite is determined according to the operating temperature range of the internal single unit of the micro-nano satellite; the temperature range of the structural components in the micro-nano satellite is the widest, while the operating temperature range of the battery is the narrowest, so the battery needs to be insulated and actively heated during the design.

[0036] Step 2: Design the micro-nano satellite configuration layout:

[0037] In the configuration and layout design, the constraints of the thermal control subsystem on the layout and the implementation space of the thermal control products are considered to achieve the organic integration of the structural subsystem and the thermal control subsystem; the details are as follows:

[0038] Design of the main load-bearing structure of micro-nano satellite:

[0039] Specifically include: the size envelope design of the main load-bearing structure of the micro-nano satellite, the integrated shell design, the internal reinforcement rib design of the integrated shell, the thickening design of the shell surface connection, and the local thickening design of the separation mechanism support installation;

[0040] Design of regional layout of single unit inside micro-nano satellite:

[0041] PCB components are installed in a stacked manner. The satellite computer, battery control module, GNSS module and S measurement and control machine are installed separately in different areas. The gyroscope and DCDC module are installed in an integrated shell. The internal space of the micro-nano satellite is compact and not enough to set up a burn-in structure. The solar cell array is body-mounted and directly installed on the sun-facing side of the micro-nano satellite. The cloth area is designed according to the input requirements of the energy balance. The external antennas including the GPS antenna and the S measurement and control antenna are body-mounted to reduce the overall size.

[0042] Step 3: Based on the interface input file, design the mechanical interface and thermal interface of the micro-nano satellite in parallel, as follows:

[0043] The mechanical interface design of the micro-nano satellite includes: the connection locating pins between the micro-nano satellite and the separation mechanism are provided with corresponding holes in the integrated shell; the micro-nano satellite contact electrical connector and the onboard star contact electrical connector ensure that the docking position and docking depth meet the use requirements; the travel switch is installed outside the integrated shell and redundant design is considered; the remaining mechanisms are installed on the micro-nano satellite base plate and corresponding holes are provided.

[0044] The thermal interface design of micro-nano satellites includes: the thermal insulation design is completed by combining thermal insulation gaskets and thermal insulation multi-layer materials between the mechanical interface installation interface, between the body-mounted solar cell array and the integrated shell, and between other mechanisms and the base plate.

[0045] Step 4: Design the heat dissipation method of the micro-nano satellite, including the location of the heat dissipation surface and the size of the heat dissipation surface, as follows:

[0046] The heat dissipation surface is selected at the location where the micro-nano satellite absorbs the least solar radiation, the earth radiation and earth reflection reaching the heat dissipation surface are the smallest, and the internal heat is concentrated. The location is selected with the largest contact area with the single unit, and all exposed surfaces of the micro-nano satellite shell are used as heat dissipation surfaces to the maximum extent; the heat transfer path between each single unit inside the micro-nano satellite and the shell is as short as possible, and the temperature of the single unit inside the satellite can be indirectly controlled by controlling the shell temperature;

[0047] Substitute the external heat flux absorbed by each surface of the micro-nano satellite obtained in step 3 and the size of the internal heat source into the heat balance equation to determine the size of the heat dissipation surface required to maintain the internal single-unit average temperature at the allowable average temperature of each single unit of the micro-nano satellite; According to the thermal network method, there is no obvious gradient in the temperature of the micro-nano satellite shell. Based on this characteristic, the micro-nano satellite as a whole is regarded as a node, which only performs radiation heat exchange externally and exchanges heat with the internal heat source internally through heat conduction and heat radiation;

[0048] Let the expected node temperature be T p , iterative solution, to obtain the required heat dissipation area Ahd:

[0049]

[0050] Where: Ai is the area of ​​the i-th heat dissipation surface of the micro-nano satellite; P is the internal power consumption of the satellite; αi is the surface infrared emissivity of the i-th heat dissipation surface, and n represents the total number of heat dissipation surfaces; εi is the surface solar radiation absorptivity of the i-th heat dissipation surface; QS is solar radiation; QA is earth reflected radiation; QIR is earth infrared radiation; Qout is the infrared radiation of external components; BSi is the average solar view factor of the entire surface of the i-th heat dissipation surface; BEi is the average earth view factor of the entire surface of the i-th heat dissipation surface, which is usually taken as 0.3; Boi is the view factor of the satellite relative to the external components; C is the safety factor considering the simplified calculation of the influence of heat leakage.

[0051] Finally, determine the specific heat dissipation measures based on the location of the heat dissipation surface.

[0052] Step 5: Design the isothermal method of the micro-nano satellite and integrate the thermal control components into the micro-nano satellite structural subsystem, including thermal conductive materials, surface treatment of structural parts, thermal insulation gaskets, MLI and thermal conductive fillers to improve the thermal control performance, as follows:

[0053] The isothermal treatment of the micro-nano satellite is designed, including: black anodizing treatment of the inner wall of the aluminum alloy integrated shell to avoid local high temperature; using thermal conductive fillers to make full contact between the single unit inside the micro-nano satellite and the heat dissipation surface, thereby enhancing the heat conduction between the single unit inside the micro-nano satellite and the heat dissipation surface; using aluminum spacer supports between PCB boards; using fiberglass spacer supports when the battery is installed with spacer.

[0054] Example 1

[0055] Combination Figure 1 to Figure 7 , a structural thermal control integrated design method for micro-nano satellites, the specific steps are as follows:

[0056] Step 1: Comprehensively consider the input conditions of the micro-nano satellite, including load-bearing, size, mass, mechanical interface, external heat flow and internal heat source, and conduct an integrated analysis of the structural subsystem and thermal control subsystem.

[0057] Specifically, the load-bearing constraints of the micro-nano satellite include: static load of the separation mechanism 5000N, separation impact of the separation mechanism 1000g, vibration fundamental frequency requirement <70Hz, static load deformation requirement <1mm.

[0058] Specifically, the size and mass constraints of micro-nano satellites include: mass ≤3.5kg, and size envelope not exceeding 270mm×270mm×55mm.

[0059] Specifically, the mechanical interface of the micro-nano satellite is a connection method between the micro-nano satellite and the separation mechanism. The separation mechanism has four connection points in the input conditions: a first connection point 1, a second connection point 2, a third connection point 3, and a fourth connection point 4. There are four positioning pins made of polyimide at each connection point. The carrier satellite supplies power to the micro-nano satellite through a contact electrical connector (5, 6). At the same time, a separation identification plate (7, 8) is installed to determine whether the micro-nano satellite is separated from the carrier satellite. A 4kg attachment device is mounted on the bottom plate. The shell design of the micro-nano satellite has a corresponding mechanical interface.

[0060] Specifically, the external heat flow of the micro-nano satellite requires a comprehensive consideration of the orbit, attitude and thermal boundary conditions of the micro-nano satellite; the micro-nano satellite orbit is a sun-synchronous orbit with an orbital altitude of 650km, an orbital inclination of 97.6°, and an ascending node local time of 18:30. The overall coordinate system is determined according to the right-hand rule, +X is the flight direction on the orbit, +Z is the direction of the micro-nano satellite to the ground during flight, and the size of the spatial external heat flow incident on each surface of the micro-nano satellite is calculated by UG software according to the flight attitude. It is known that the incident external heat flow of the micro-nano satellite is the largest during the winter solstice, and it is in a fully illuminated orbit, which is an extremely high temperature condition of the micro-nano satellite; the external heat flow is the smallest during the summer solstice, and there is a partial shadow area in the satellite orbit during the summer solstice, which is an extremely low temperature condition of the micro-nano satellite. Then, the heat dissipation surface positions of the micro-nano satellite are determined as +X surface, -X surface, +Z surface, -Z surface, -Y surface, and the heat insulation surface position is -Y surface.

[0061] Specifically, the size of the internal heat source of the micro-nano satellite and the operating temperature range of the internal single unit are important parameters that determine the overall temperature condition of the micro-nano satellite. The total internal heat source of the micro-nano satellite is 6W. According to the size of the internal heat source, the individual units of the micro-nano satellite are reasonably distributed to avoid the concentration of high-power consumption components. Among them, the heat consumption of the satellite computer 40 is 0.7W, the heat consumption of the battery control module 42 is 0.6W, the heat consumption of the GNSS module 43 is 0.7W, the heat consumption of the S measurement and control machine 44 is 0.65W, the heat consumption of the gyroscope 46 is 0.4W, and the heat consumption of the DCDC module is 0. The heat consumption of block 41 is 0W; the temperature gradient of the micro-nano satellite can be determined according to the operating temperature range of a single unit inside the micro-nano satellite. There is no device inside the micro-nano satellite that is sensitive to structural deformation. Therefore, the temperature range of the structural components in the micro-nano satellite is the widest, and the operating temperature range of the battery is the narrowest. The battery 24 is installed on the battery mounting bracket 23. When the partition column is installed, the partition column 21 made of fiberglass is used, that is, the heat-insulating installation is adopted. The heating belt is wrapped around the outside of the battery. The active heating power consumption is 0.5W, and the heating temperature range is 0-5°C.

[0062] Step 2: Consider the constraints of the thermal control subsystem on the layout and the implementation space of the thermal control products in the configuration and layout design to achieve the organic integration of the structural subsystem and the thermal control subsystem.

[0063] Specifically, the micro-nano satellite configuration layout design includes: the main load-bearing structure of the micro-nano satellite is a rectangular parallelepiped of 270mm×270mm×50mm, and the outer shell is an integrated shell 17 with cross-shaped reinforcement ribs. In order to withstand a static tensile force of 5000N, cross-shaped reinforcement ribs 34 are added inside the main shell, 4 support columns (26~29) are designed at the connection of the shell surface, and 4 bosses (30~33) are designed at the installation of the separation mechanism support. The main purpose of the cross-shaped reinforcement ribs 34 is to improve the overall rigidity of the shell and avoid deformation of the shell. The cross-shaped reinforcement ribs 34 separate the micro-nano satellite into four areas. The PCB components are installed in a stacked manner. The four single machines, namely the satellite computer 40, the battery control module 42, the GNSS module 43 and the S measurement and control machine 44, are installed in four areas. The gyroscope 46 and the DCDC module 41 are small in size and installed on the inside of the integrated shell. The solar cell array 19 is body-mounted and directly installed on the -Y surface. The cloth area is designed according to the input requirements of the energy balance. The external antennas including the GPS antenna 25 and the S measurement and control antenna 39 are all body-mounted to facilitate reducing the overall size.

[0064] Step 3: Based on the interface input file, the mechanical interface and thermal interface of the micro-nano satellite are designed in parallel.

[0065] Specifically, the mechanical interface design of the micro-nano satellite includes: the connection positioning pins between the micro-nano satellite and the separation mechanism are provided with corresponding installation holes (9-12) in the integrated shell, the micro-nano satellite contact electrical connector (15, 16) and the onboard star contact electrical connector ensure the docking position, the docking depth meets the use requirements, the travel switch (13, 14) is installed in the integrated shell, and the attachment device is installed on the bottom plate 47, all of which have corresponding hole positions.

[0066] The thermal interface design of the micro-nano satellite includes: the thermal insulation installation is completed by combining the thermal insulation gasket and the sun-facing thermal insulation multilayer 18 between the body-mounted solar cell array 19 and the integrated shell 17, and the thermal insulation installation is completed by combining the thermal insulation gasket and the shady-side thermal insulation multilayer 20 between the attachment device and the base plate 47.

[0067] Step 4: Conduct heat dissipation design for micro-nano satellites, including determining the location of the heat dissipation surface and designing the size of the heat dissipation surface.

[0068] Specifically, the heat dissipation design of the micro-nano satellite includes: the heat dissipation surface is selected where the absorbed solar radiation is the minimum, the earth radiation and earth reflection reaching the heat dissipation surface are the minimum, the heat flux absorbed by the +Y surface of the micro-nano satellite is the minimum, but the +Y surface is connected to the attachment mechanism, and the interface is insulated by a heat-insulating multilayer material and cannot be used as a heat dissipation surface. The heat dissipation surface is selected as +X, -X, +Z, -Z, and -Y surfaces. The heat sources in the micro-nano satellite are evenly arranged, and each unit is directly connected to the integrated shell. The heat transfer path between each unit inside the micro-nano satellite and the shell is short. Therefore, all exposed surfaces of the micro-nano satellite shell are used as heat dissipation surfaces to the maximum extent. The external heat flux absorbed by each surface of the micro-nano satellite obtained in step 3 and the size of the internal heat source are substituted into the heat balance equation to determine the size of the heat dissipation surface required to maintain the average temperature of the internal unit at the allowable average temperature of each unit of the micro-nano satellite; according to the thermal network method, the temperature of the micro-nano satellite shell has no obvious gradient. According to this characteristic, the micro-nano satellite as a whole is regarded as a node, which only performs radiation heat exchange externally and exchanges heat with the internal heat source internally through heat conduction and heat radiation.

[0069] Let the expected node temperature be T p , iterative solution, get the required heat dissipation area A hd :

[0070]

[0071] Where: A i is the i-th heat dissipation surface area of ​​the micro-nano satellite; P is the internal power consumption of the satellite; α i is the surface infrared emissivity of the i-th heat dissipation surface, n represents the total number of heat dissipation surfaces; ε i is the surface solar radiation absorption rate of the i-th heat dissipation surface; Q S is solar radiation; Q A Q is the reflected radiation of the earth;IR is the earth's infrared radiation; Q out is the infrared radiation of external components; B Si is the average solar viewing angle coefficient of the entire surface of the i-th heat dissipation surface; B Ei B is the average value of the earth's viewing angle coefficient of the entire surface of the i-th heat dissipation surface, usually 0.3; oi is the viewing angle coefficient of the satellite relative to the external components; C is the safety factor for simplifying the calculation of heat leakage.

[0072] Taking the design safety factor C = 1.2, the external heat flux of the micro-nano satellite is calculated to be 519W / m on the -Y surface. 2 , +Y surface heat flux 0W / m 2 , +Z surface heat flux 173W / m 2 , -Z surface heat flux 0W / m 2 ,-+X surface heat flux 0W / m 2 , -X surface heat flux 0W / m 2 Combined with the internal heat source size in step 1, the heat dissipation area of ​​the -Y surface is calculated to be 0.013m 2 The heat dissipation surface area of ​​the surrounding body is 0.052m 2 , total heat dissipation area 0.065m 2 The specific heat dissipation measures are as follows: the +X, -X, +Z, -Z and +Y surfaces are sprayed with inorganic white paint KS-ZA as heat dissipation surfaces, and the GPS antenna 25 is sprayed with organic white paint S781.

[0073] Step 5: Design the isothermalization method of the micro-nano satellite and integrate thermal control components into the micro-nano satellite structural subsystem, including thermal conductive materials, surface treatment of structural parts, thermal insulation gaskets, MLI and thermal conductive fillers to improve thermal control performance.

[0074] Specifically, the design of integrated thermal control components in the micro-nano satellite structure includes: the integrated shell 17 is made of aluminum alloy material, the power control board support frame 22 and the GNSS support frame 45 are installed by filling with thermal conductive silicone grease, the PCBs of the satellite computer 40, the battery control module 42, the GNSS module 43 and the S measurement and control machine 44 are thermally installed between the aluminum partitions supporting them, and the inner wall of the integrated shell, namely the battery control module support frame mounting surface 35, the satellite computer support frame mounting surface 36, the GNSS module support frame mounting surface 37 and the S measurement and control machine support frame mounting surface 38, are black anodized to avoid local high temperature.

[0075] In summary, the structural thermal control integrated design method for micro-nano satellites described in the present invention integrates the structural subsystem and thermal control subsystem of the micro-nano satellite through an integrated design method to achieve efficient thermal control while meeting the structural strength, thereby achieving better heat dissipation, heat insulation and temperature balance effects in a limited space. This design method can not only reduce the overall mass of the micro-nano satellite, but also significantly improve the thermal control efficiency and enhance the reliability of the micro-nano satellite in orbit.

Claims

1. A structural thermal control integrated design method for micro-nano satellites, characterized in that: Here are the steps: Step 1: Comprehensively consider the input conditions of the micro-nano satellite, including load-bearing, size, mass, mechanical interface, external heat flow and internal heat source, and integrate the structural subsystem and thermal control subsystem; Step 2: Design the micro-nano satellite configuration layout: Consider the constraints of the thermal control subsystem on the layout and the implementation space of the thermal control products in the configuration and layout design to achieve the organic integration of the structural subsystem and the thermal control subsystem; Step 3: Based on the interface input file, the mechanical interface and thermal interface of the micro-nano satellite are designed in parallel; Step 4: Design the heat dissipation method of the micro-nano satellite, including the location of the heat dissipation surface and the size of the heat dissipation surface; Step 5: Design the isothermalization method of the micro-nano satellite and integrate thermal control components into the micro-nano satellite structural subsystem, including thermal conductive materials, surface treatment of structural parts, thermal insulation gaskets, MLI and thermal conductive fillers to improve thermal control performance.

2. The method for integrated structural thermal control design for micro-nano satellites according to claim 1, characterized in that: In step 1, the load-bearing constraints of the micro-nano satellite include: static load of the separation mechanism, separation impact of the separation mechanism, vibration fundamental frequency requirements and static load deformation requirements; The mechanical interface of the micro-nano satellite includes the following: the connection method between the micro-nano satellite and the separation mechanism, the connection point position of the separation mechanism in the input conditions, the material of the positioning pin at the connection point, the power supply method between the micro-nano satellite and the carrier satellite, the installation position of the travel switch, and the mechanical interface of the micro-nano satellite to other mechanisms; The external heat flow of a micro-nano satellite requires comprehensive consideration of the orbit, attitude and thermal boundary conditions of the micro-nano satellite, and calculation of the magnitude of the heat flow of solar radiation, earth infrared radiation, and earth reflected radiation received by the external surfaces of the micro-nano satellite, as well as the heat flow impact of other spacecraft on the micro-nano satellite.

3. The method for integrated structural thermal control design for micro-nano satellites according to claim 2, characterized in that: The orbital parameters of the micro-nano satellite include the orbital altitude, orbital inclination, and ascending node time; the attitude parameters of the micro-nano satellite include the overall coordinate system of the micro-nano satellite, the in-orbit flight direction, and the in-orbit direction to the earth; based on the flight attitude, the magnitude of the external heat flux incident on each surface of the micro-nano satellite in extreme high temperature conditions and extreme low temperature conditions is calculated, and then the position of the heat dissipation surface and the heat insulation surface of the micro-nano satellite are determined.

4. The method for integrated structural thermal control design for micro-nano satellites according to claim 3 is characterized in that: In step 1, the size of the internal heat source of the micro-nano satellite and the operating temperature range of the internal single unit are important parameters that determine the overall temperature condition of the micro-nano satellite. The micro-nano satellite units are reasonably distributed according to the size of the internal heat source to avoid the concentration of high-power single units; the temperature gradient of the micro-nano satellite is determined according to the operating temperature range of the internal single unit of the micro-nano satellite; the temperature range of the structural components in the micro-nano satellite is the widest, while the operating temperature range of the battery is the narrowest. The battery needs to be designed with thermal insulation and active heating in the design.

5. The structural thermal control integrated design method for micro-nano satellites according to claim 1 is characterized in that: In step 2, the micro-nano satellite configuration layout is designed, including the design of the main load-bearing structure of the micro-nano satellite and the design of the internal single-machine regional layout of the micro-nano satellite, as follows: Design of the main load-bearing structure of micro-nano satellite: Specifically include: the size envelope design of the main load-bearing structure of the micro-nano satellite, the integrated shell design, the internal reinforcement rib design of the integrated shell, the thickening design of the shell surface connection, and the local thickening design of the separation mechanism support installation; Design of regional layout of single unit inside micro-nano satellite: PCB components are installed in a stacked manner. The satellite computer, battery control module, GNSS module and S measurement and control machine are installed separately in different areas. The gyroscope and DCDC module are installed in an integrated shell. The internal space of the micro-nano satellite is compact and not enough to set up a burn-in structure. The solar cell array is body-mounted and directly installed on the sun-facing side of the micro-nano satellite. The cloth area is designed according to the input requirements of the energy balance. The external antennas including the GPS antenna and the S measurement and control antenna are body-mounted to reduce the overall size.

6. The method for integrated structural thermal control design for micro-nano satellites according to claim 1, characterized in that: In step 3, the mechanical interface and thermal interface of the micro-nano satellite are designed in parallel according to the interface input file, as follows: The mechanical interface design of the micro-nano satellite includes: the connection locating pins between the micro-nano satellite and the separation mechanism are provided with corresponding holes in the integrated shell; the micro-nano satellite contact electrical connector and the onboard star contact electrical connector ensure that the docking position and docking depth meet the use requirements; the travel switch is installed outside the integrated shell and redundant design is considered; the remaining mechanisms are installed on the micro-nano satellite base plate and corresponding holes are provided.

7. The method for integrated structural thermal control design for micro-nano satellites according to claim 6, characterized in that: The thermal interface design of micro-nano satellites includes: the thermal insulation design is completed by combining thermal insulation gaskets and thermal insulation multi-layer materials between the mechanical interface installation interface, between the body-mounted solar cell array and the integrated shell, and between other mechanisms and the base plate.

8. The method for integrated structural thermal control design for micro-nano satellites according to claim 1, characterized in that: In step 4, the heat dissipation method of the micro-nano satellite is designed, including the location of the heat dissipation surface and the size of the heat dissipation surface area, as follows: The heat dissipation surface is selected at the location where the micro-nano satellite absorbs the least solar radiation, the earth radiation and earth reflection reaching the heat dissipation surface are the smallest, and the internal heat is concentrated. The location is selected with the largest contact area with the single unit, and all exposed surfaces of the micro-nano satellite shell are used as heat dissipation surfaces to the maximum extent; the heat transfer path between each single unit inside the micro-nano satellite and the shell is as short as possible, and the temperature of the single unit inside the satellite can be indirectly controlled by controlling the shell temperature; Substitute the external heat flux absorbed by each surface of the micro-nano satellite obtained in step 3 and the size of the internal heat source into the heat balance equation to determine the size of the heat dissipation surface required to maintain the internal single-unit average temperature at the allowable average temperature of each single unit of the micro-nano satellite; According to the thermal network method, there is no obvious gradient in the temperature of the micro-nano satellite shell. Based on this characteristic, the micro-nano satellite as a whole is regarded as a node, which only performs radiation heat exchange to the outside and exchanges heat with the internal heat source through heat conduction and heat radiation. Let the expected node temperature be T p , iterative solution, get the required heat dissipation area A hd : Where: A i is the i-th heat dissipation surface area of ​​the micro-nano satellite; P is the internal power consumption of the satellite; α i is the surface infrared emissivity of the i-th heat dissipation surface, and n represents the total number of heat dissipation surfaces; ε i is the surface solar radiation absorption rate of the i-th heat dissipation surface; Q S is solar radiation; Q A Q is the reflected radiation of the earth; IR is the earth's infrared radiation; Q out is the infrared radiation of external components; B Si is the average solar viewing angle coefficient of the entire surface of the i-th heat dissipation surface; B Ei is the average value of the earth's viewing angle coefficient of the entire surface of the i-th heat dissipation surface, B oi is the viewing angle coefficient of the satellite relative to the external components; C is the safety factor considering the simplified calculation of heat leakage effect; Finally, determine the specific heat dissipation measures based on the location of the heat dissipation surface.

9. The method for integrated structural thermal control design for micro-nano satellites according to claim 1, characterized in that: In step 5, the isothermal treatment of the micro-nano satellite is designed, including: black anodizing treatment of the inner wall of the aluminum alloy integrated shell to avoid local high temperature; using thermal conductive fillers to make full contact between the single unit inside the micro-nano satellite and the heat dissipation surface, thereby enhancing the heat conduction between the single unit inside the micro-nano satellite and the heat dissipation surface; using aluminum spacer supports between PCB boards; and using fiberglass spacer supports when the battery is installed with spacers.

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