A micro-nano satellite oriented structure and thermal control integrated design method

Abstract

The application relates to a micro-nano satellite structure thermal control integrated design method, which comprises the following steps: firstly, considering the constraint conditions of the micro-nano satellite, including bearing, size, mass, mechanical interface, external heat flow and internal heat source, integrating the micro-nano satellite structure subsystem and the thermal control subsystem, and carrying out integrated design; then, designing the micro-nano satellite configuration and layout; then, parallelly designing the mechanical interface and the thermal interface of the micro-nano satellite; then, designing the heat dissipation mode of the micro-nano satellite; finally, designing the micro-nano satellite isothermal mode. In the application, the structure components of the micro-nano satellite are made of heat-conducting materials, and are integrated with thermal control coatings, surface treatment of structure parts, heat insulation pads and multilayer heat insulation materials, so that the micro-nano satellite is miniaturized and lightened, and the thermal control efficiency and the structure stability are improved. The application is suitable for the efficient thermal control requirement of the micro-nano satellite, significantly reduces the mass of the micro-nano satellite, and enhances the on-orbit reliability of the micro-nano satellite.

Description

Technical Field

[0001] This invention belongs to the field of micro and nano satellites, and specifically relates to an integrated design method for the structure and thermal control of micro and nano satellites. Background Technology

[0002] With the continuous development of aerospace technology, microsatellites and nanosatellites have been widely used in scientific exploration, remote sensing, and communications due to their small size, low cost, and flexible mission capabilities. However, the structural and thermal control problems faced in the design process of microsatellites and nanosatellites are becoming increasingly prominent. The structural design of microsatellites and nanosatellites must meet the mechanical load-bearing requirements during launch and the stability during on-orbit operation, while the thermal control design must cope with the complex space thermal environment and ensure that the temperature of the satellite's internal equipment remains within the allowable range. However, due to the limitations of the size and mass of microsatellites and nanosatellites, their internal space is limited, making it difficult to achieve efficient structural and thermal control designs independently.

[0003] In traditional satellite design, structure and thermal control are generally designed and optimized as two independent subsystems. While this approach is more suitable for large satellite design, in micro and nano satellite design, due to strict constraints on size and mass, separating the two designs leads to wasted space and increased weight, easily complicating the micro and nano satellite design, affecting system reliability, and making it difficult to achieve miniaturization, lightweighting, and high efficiency of micro and nano satellites.

[0004] In existing technologies, heat sinks, heat pipes, and louvers are commonly used to control heat transfer, and active heating is employed for temperature-sensitive components to improve thermal control performance. However, in microsatellites and nanosatellites, traditional thermal control methods and structural designs often fail to achieve efficient thermal control within limited size and mass constraints. This results in the thermal control system occupying significant space and energy, and increasing the overall mass of the microsatellite. Furthermore, microsatellites and nanosatellites are susceptible to temperature variations in the external environment during on-orbit operation. Therefore, designing a system with both efficient thermal control performance and structural strength within limited mass and space has become a major challenge in microsatellite design. Summary of the Invention

[0005] The purpose of this invention is to propose an integrated structural and thermal control design method for micro and nano satellites. Based on the constraints of micro and nano satellites in terms of load-bearing capacity, size and mass, mechanical interfaces, thermal environment and energy utilization, this method integrates the structural and thermal control subsystems of micro and nano satellites. While ensuring the high efficiency of thermal control performance of micro and nano satellites, it also achieves miniaturization and lightweighting of micro and nano satellites, thereby improving the reliability and stability of micro and nano satellites in orbit.

[0006] The technical solution for achieving the present invention is: a structural thermal control integrated design method for micro / nano satellites, comprising the following steps:

[0007] Step 1: Taking into account the input conditions of the micro-nano satellite, including load-bearing capacity, size, mass, mechanical interface, external heat flow and internal heat source, conduct an integrated design of the structural subsystem and thermal control subsystem;

[0008] Step 2: Design the configuration and layout of micro / nano satellites:

[0009] 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 in order to achieve the organic integration of the structural subsystem and the thermal control subsystem.

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

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

[0012] Step 5: Design the isothermal method for the micro / nano satellite and integrate thermal control components into the micro / nano satellite structural subsystem, including thermally conductive materials, surface treatment of structural components, thermal insulation pads, MLI and thermally conductive fillers, to improve thermal control performance.

[0013] Compared with the prior art, the significant advantages of this invention are:

[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 proportion of effective payload, but also improves the stability and reliability of on-orbit operation, which is especially suitable for micro-nano satellite missions with high requirements for thermal control efficiency.

[0015] (2) Optimize the thermal control layout of high-power single units: For the layout of high-power single units, this invention integrates thermal control requirements and reasonably arranges high-power single units to ensure that these units have the best heat dissipation channels, thereby improving the temperature uniformity inside the micro-nano satellite and effectively avoiding local overheating.

[0016] (3) Integrating 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 internal units, and ensure the stability of the micro-nano satellite thermal control system.

[0017] (4) Modular Design: This invention designs the PCB support frame and partitions as modular components. These modular components possess both load-bearing and thermal control functions. For individual units requiring thermally conductive installation, the partition material is thermally conductive; for units requiring thermally insulated installation, only the partition material needs to be replaced with thermally insulated material. This not only achieves stability in the micro / nano satellite structure support but also improves thermal control efficiency, further reducing the overall mass of the micro / nano satellite while decreasing material usage. It enhances the flexibility of thermal design while reducing the complexity of traditional thermal control system design.

[0018] Reduced design iteration time: The design process considers both mechanical and thermal input conditions, and designs the structural and thermal control subsystems of micro- and nano-satellites in parallel. This reduces the number of iterative designs required in traditional designs due to the separate design of the structural and thermal control subsystems, and effectively improves the design efficiency of micro- and nano-satellites. Attached Figure Description

[0019] Figure 1 This is a flowchart of the integrated thermal control design method for micro / nano satellite structures according to the present invention.

[0020] Figure 2 This is a structural diagram of a micro / nano satellite separation mechanism exemplified by the present invention.

[0021] Figure 3 This is an example of the overall design of a micro / nano satellite according to the present invention.

[0022] Figure 4 This is a structural diagram of a micro / nano satellite substrate exemplified by the present invention.

[0023] Figure 5 This is a structural diagram of a modular design for a micro / nano satellite, as exemplified by this invention.

[0024] Figure 6 This is a diagram illustrating the integrated shell structure of a micro / nano satellite, as exemplified by this invention.

[0025] Figure 7 This is a single-unit layout diagram of the internal structure of a micro / nano satellite, as exemplified by this invention. Detailed Implementation

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0027] The technical solutions of the various embodiments of the present invention can be combined with each other, but only if they can be implemented by those skilled in the art. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

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

[0029] Combination Figure 1 A structural thermal control integrated design method for micro / nano satellites, comprising the following steps:

[0030] Step 1: Taking into account the input conditions of the micro-nano satellite, including load-bearing capacity, size, mass, mechanical interfaces, external heat flow, and internal heat sources, conduct an integrated analysis of the structural subsystem and thermal control subsystem, as detailed below:

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

[0032] The mechanical interfaces of microsatellites and nanosatellites include the following: the connection method between the microsatellite and the separation mechanism, the location of the connection point of the separation mechanism in the input conditions, the material of the positioning pin at the connection point, the power supply method between the microsatellite and the carrier satellite, the installation location of the limit switch, and the mechanical interfaces between the microsatellite and other mechanisms.

[0033] The external heat flow of microsatellites and nanosatellites requires comprehensive consideration of their orbits, attitudes, and thermal boundary conditions. It is necessary to calculate the magnitude of heat flow from solar radiation, Earth's infrared radiation, and Earth's albedo radiation on each of the microsatellite's external surfaces, as well as the influence of heat flow from other spacecraft on the microsatellites and nanosatellites.

[0034] The orbital parameters of microsatellites include orbital altitude and orbital inclination, as well as the time of the ascending node; the attitude parameters of microsatellites include the overall coordinate system of microsatellites, the direction of flight in orbit, and the direction of flight to the ground in orbit; based on the flight attitude, the magnitude of the external heat flux incident on each surface of the microsatellite in extreme high temperature and extreme low temperature conditions is calculated, thereby determining the location of the heat dissipation surface and the heat insulation surface of the microsatellite.

[0035] The size of the internal heat source and the operating temperature range of the internal components of a microsatellite are important parameters that determine the overall temperature condition of the microsatellite. The individual components of the microsatellite should be reasonably distributed according to the size of the internal heat source to avoid the concentration of high-power components. The temperature gradient of the microsatellite should be determined according to the operating temperature range of the internal components. The structural components of the microsatellite have the widest temperature range, while the battery has the narrowest operating temperature range. Therefore, the design of the battery needs to include heat insulation and active heating.

[0036] Step 2: Design the configuration and layout of micro / nano satellites:

[0037] The configuration and layout design takes into account the constraints of the thermal control subsystem on the layout and the implementation space of the thermal control products, in order to achieve the organic integration of the structural subsystem and the thermal control subsystem; specifically as follows:

[0038] Design of the main load-bearing structure for micro / nano satellites:

[0039] Specifically, this includes: the size envelope design of the main load-bearing structure of the micro-nano satellite, the integrated shell design, the internal reinforcing rib design of the integrated shell, the thickening design at the shell surface connection, and the local thickening design at the installation location of the separation mechanism support.

[0040] Microsatellite internal single-unit regional layout design:

[0041] The PCB components are stacked, with the satellite computer, battery control module, GNSS module, and S-tracking and control unit installed separately in different areas. The gyroscope and DC-DC module are installed in an integrated housing. The internal space of the micro-nano satellite is compact and insufficient for a wire-burning structure. The solar array is body-mounted and directly installed on the sun-facing side of the micro-nano satellite. The array area is designed according to the energy balance input requirements. The external antennas, including the GPS antenna and the S-tracking and control antenna, are all body-mounted to facilitate the reduction of the overall size.

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

[0043] The mechanical interface design for the micro-nano satellite includes: the connection and positioning pins between the micro-nano satellite and the separation mechanism are provided with corresponding holes in the integrated housing; the micro-nano satellite contact electrical connector and the satellite-mounted contact electrical connector ensure that the docking position and docking depth meet the usage requirements; the limit switch is installed outside the integrated housing with redundant design considerations; and the remaining mechanisms are installed on the micro-nano satellite base plate with corresponding holes.

[0044] The thermal interface design of micro-nano satellites includes the use of thermal insulation pads and multi-layered thermal insulation materials to complete the thermal insulation design between mechanical interface mounting interfaces, 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 for micro / nano satellites, including the location and size of the heat dissipation surface, as detailed below:

[0046] The heat dissipation surface is selected at the part of the micro-nano satellite where the solar radiation absorbed is the least, the Earth radiation and Earth reflection reaching the heat dissipation surface are the least, and the internal heat is concentrated. In addition, the part is selected to have the largest contact area with the individual unit. 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 individual unit inside the micro-nano satellite and the shell is as short as possible. By controlling the shell temperature, the temperature of the individual units inside the satellite can be indirectly controlled.

[0047] Substitute the external heat flow absorbed by each surface of the micro-nano satellite obtained in step 3, as well as 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 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 outer shell of the micro-nano satellite does not have a significant gradient. Based on this characteristic, the micro-nano satellite as a whole is regarded as a node. This node only conducts radiative heat exchange to the outside and exchanges heat with the internal heat source through heat conduction and heat radiation.

[0048] Let the expected node temperature be T. p The required heat dissipation area Ahd is obtained through iterative solution.

[0049]

[0050] In the formula: 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 albedo radiation; QIR is Earth infrared radiation; Qout is infrared radiation of external components; BSi is the average solar viewing angle coefficient of the entire surface of the i-th heat dissipation surface; BEi is the average Earth viewing angle coefficient of the entire surface of the i-th heat dissipation surface, usually taken as 0.3; Boi is the viewing angle coefficient of the satellite relative to external components; C is the safety factor considering the simplified calculation of heat leakage effects.

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

[0052] Step 5: Design the isothermal treatment method for the micro / nano satellite, and integrate thermal control components into the micro / nano satellite structural subsystem, including thermally conductive materials, surface treatment of structural components, thermal insulation pads, MLI (Medium-Liquidity Interchange) and thermally conductive fillers, to improve thermal control performance, as detailed below:

[0053] The design of the microsatellite isotherm treatment includes: black anodizing of the inner wall of the integrated aluminum alloy shell to avoid localized high temperatures; using thermally conductive fillers to ensure full contact between the internal components of the microsatellite and the heat dissipation surface, enhancing heat conduction between the internal components and the heat dissipation surface; using aluminum spacers for support between PCB boards; and using fiberglass spacers for support when the battery is installed with spacers.

[0054] Example 1

[0055] Combination Figures 1 to 7 A structural thermal control integrated design method for micro / nano satellites, the specific steps of which are as follows:

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

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

[0058] Specifically, the size and mass constraints for microsatellites include: mass ≤ 3.5 kg, and size envelope not exceeding 270 mm × 270 mm × 55 mm.

[0059] Specifically, the mechanical interface of the microsatellite is the connection method between the microsatellite and the separation mechanism. The separation mechanism has four connection points in the input conditions: first connection point 1, second connection point 2, third connection point 3, and fourth connection point 4. There are four positioning pins made of polyimide at each connection point. The satellite on board supplies power to the microsatellite through contact electrical connectors (5, 6). At the same time, separation identification plates (7, 8) are installed to determine whether the microsatellite and the satellite on board have separated. The base plate is equipped with an attachment device weighing 4kg. The outer shell of the microsatellite has a corresponding mechanical interface.

[0060] Specifically, the external heat flux of the microsatellite needs to be determined by comprehensively considering its orbit, attitude, and thermal boundary conditions. The microsatellite is in a sun-synchronous orbit at an altitude of 650 km and an inclination of 97.6°. The local time at the ascending node is 18:30. Using the right-hand rule, the global coordinate system is determined, with +X representing the on-orbit flight direction and +Z representing the microsatellite's direction relative to the Earth during flight. Based on the flight attitude, the magnitude of the incident external heat flux on each surface of the microsatellite is calculated using UG software. It is found that the incident external heat flux is maximum during the winter solstice, when the satellite is in a fully illuminated orbit, representing the extreme high-temperature condition. The external heat flux is minimum during the summer solstice, when the satellite's orbit has a partially shaded area, representing the extreme low-temperature condition. Therefore, the locations of the microsatellite's heat dissipation surfaces are determined as +X, -X, +Z, -Z, and -Y surfaces, while the location of the heat insulation surface is the -Y surface.

[0061] Specifically, the size of the internal heat source and the operating temperature range of the internal components of a microsatellite are crucial parameters determining its overall temperature characteristics. The total internal heat source of the microsatellite is 6W. Based on the size of the internal heat source, the various components of the microsatellite are rationally distributed to avoid concentrating high-power components. Specifically, the heat dissipation of the following components is as follows: Satellite computer 40: 0.7W; Battery control module 42: 0.6W; GNSS module 43: 0.7W; Telemetry and command unit 44: 0.65W; Gyroscope 46: 0.4W; DC-DC module... Block 41 has a heat dissipation of 0W. The temperature gradient of the microsatellite can be determined based on the operating temperature range of the individual units inside the microsatellite. There are no devices inside the microsatellite that are sensitive to structural deformation. Therefore, the structural components in the microsatellite have the widest temperature range, while the battery has the narrowest operating temperature range. The battery 24 is mounted on the battery mounting bracket 23. When using a spacer mounting, a fiberglass spacer 21 is used, which is a heat-insulating mounting. The battery is wrapped with a heating tape. The active heating power consumption is 0.5W, and the heating temperature range is 0~5℃.

[0062] Step 2: In the configuration and layout design, consider the constraints of the thermal control subsystem on the layout and the implementation space of the thermal control products, so as to achieve the organic integration of the structural subsystem and the thermal control subsystem.

[0063] Specifically, the microsatellite configuration and layout design includes a main load-bearing structure of 270mm×270mm×50mm cuboid, an outer shell of 17 with cross-shaped reinforcing ribs, and a cross-shaped reinforcing rib 34 added inside the main shell to withstand a static tensile force of 5000N. Four support columns (26-29) are designed at the shell surface connection, and four bosses (30-33) are designed at the separation mechanism support installation location. The main purpose of the cross-shaped reinforcing rib 34 is to improve the overall rigidity of the shell and prevent deformation of the shell. The cross-shaped reinforcing rib 34 divides the micro-nano satellite into four areas. The PCB components are stacked and installed in four areas, with the four individual units, namely the satellite computer 40, battery control module 42, GNSS module 43, and S-tracking and control unit 44, installed in the four areas. The gyroscope 46 and DC-DC module 41 are small in size and installed inside the integrated housing. The solar array 19 is body-mounted and directly mounted on the -Y surface. The area of ​​the array is designed according to the input requirements of energy balance. The external antennas, including the GPS antenna 25 and the S-tracking and control antenna 39, are all body-mounted to facilitate the reduction of the overall size.

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

[0065] Specifically, the mechanical interface design for the micro-nano satellite includes: the connection and positioning pins between the micro-nano satellite and the separation mechanism are provided with corresponding mounting holes (9-12) in the integrated housing; the micro-nano satellite contact electrical connectors (15, 16) and the satellite-mounted contact electrical connectors ensure the docking position and the docking depth meets the usage requirements; the limit switches (13, 14) are installed in the integrated housing; and the attachment device is installed on the base plate 47, all with corresponding holes.

[0066] The thermal interface design of the micro-nano satellite includes: the heat insulation installation is completed by combining the heat insulation gasket between the body-mounted solar cell array 19 and the integrated shell 17 with the heat insulation multilayer 18 on the sun-facing side; the attachment device needs to be heat-insulated by combining the heat insulation gasket between it and the base plate 47 with the heat insulation multilayer 20 on the shaded side.

[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 area.

[0068] Specifically, the heat dissipation design for the microsatellite includes: selecting heat dissipation surfaces where the absorbed solar radiation, the Earth's radiation reaching the heat dissipation surface, and the Earth's reflection are minimized; the heat flow absorbed by the +Y side of the microsatellite is minimized, but the +Y side is connected to the attachment mechanism, and the interface is treated with multi-layer heat insulation material, so it cannot be used as a heat dissipation surface; the heat dissipation surfaces are selected as +X, -X, +Z, -Z, and -Y sides; the heat sources inside the microsatellite are evenly distributed, and each unit is directly connected to the integrated shell; the heat transfer path between each unit inside the microsatellite and the shell is short, therefore, all exposed surfaces of the microsatellite shell are used as heat dissipation surfaces to the maximum extent. Substituting the external heat flow absorbed by each surface of the microsatellite obtained in step 3, as well as the size of the internal heat source, into the heat balance equation, the size of the heat dissipation surface required to maintain the average temperature of the internal units at the allowable average temperature of each unit in the microsatellite is determined; according to the thermal network method, the temperature of the microsatellite shell does not have a significant gradient. Based on this characteristic, the microsatellite as a whole is regarded as a node, which only conducts radiative heat exchange to the outside and exchanges heat with the internal heat source through heat conduction and thermal radiation.

[0069] Let the expected node temperature be T. p The required heat dissipation area A is obtained by iterative solution. hd :

[0070]

[0071] In the formula: A i α represents the heat dissipation surface area of ​​the i-th microsatellite; P represents the internal power consumption of the satellite; α i ε represents the surface infrared emissivity of the i-th heat dissipation surface, and n represents the total number of heat dissipation surfaces; i Q is the surface solar radiation absorptivity of the i-th heat dissipation surface; S Solar radiation; Q A Earth's albedo; QIR For Earth's infrared radiation; Q out For infrared radiation from external components; B Si B is the average solar viewing angle coefficient of the entire surface of the i-th heat dissipation surface; Ei B is the average Earth's viewing angle coefficient across the entire surface of the i-th heat dissipation surface, typically taken as 0.3; oi denoted as the viewing angle coefficient of the satellite relative to external components; C is the safety factor that takes into account the effects of heat leakage in simplified calculations.

[0072] Taking a design safety factor of C = 1.2, the calculated external heat flux of the microsatellite is 519 W / m on the Y-plane. 2 +Y surface heat flow 0W / m 2 +Z-side heat flux 173W / m 2 -Z-plane heat flux 0W / m 2 -+X surface heat flow 0W / m 2 -X surface heat flux 0W / m 2 Based on the size of the internal heat source in step 1, the heat dissipation area of ​​the -Y surface is calculated to be 0.013m². 2 The surface area of ​​the heat dissipation zone is 0.052m². 2 Total heat dissipation area: 0.065m² 2 The specific heat dissipation measures are as follows: the +X, -X, +Z, -Z, and +Y surfaces are coated with inorganic white paint KS-ZA, and the GPS antenna 25 is coated with organic white paint S781.

[0073] Step 5: Design the isothermal method for the micro / nano satellite and integrate thermal control components into the micro / nano satellite structural subsystem, including thermally conductive materials, surface treatment of structural components, thermal insulation pads, MLI and thermally conductive fillers, to improve thermal control performance.

[0074] Specifically, the integrated thermal control component design in the micro-nano satellite structure includes: the integrated shell 17 is made of aluminum alloy; the power control board support frame 22 and GNSS support frame 45 are installed by filling with thermally conductive silicone grease; the PCBs of the satellite computer 40, battery control module 42, GNSS module 43 and S-tracking and control unit 44 are thermally conductively installed between them and the aluminum spacers supporting them; the inner wall of the integrated shell, namely the mounting surface 35 of the battery control module support frame, the mounting surface 36 of the satellite computer support frame, the mounting surface 37 of the GNSS module support frame and the mounting surface 38 of the S-tracking and control unit support frame, is treated with black anodizing to avoid localized high temperatures.

[0075] In summary, the integrated structural and thermal control design method for micro / nano satellites described in this invention integrates the structural and thermal control subsystems of micro / nano satellites through a unified design approach. This achieves efficient thermal control while meeting structural strength requirements, thereby realizing superior heat dissipation, insulation, and temperature equalization within a limited space. This design method not only reduces the overall mass of micro / nano satellites but also significantly improves thermal control efficiency and enhances the reliability of micro / nano satellites during on-orbit operation.

Claims

1. A structural thermal control integrated design method for micro / nano satellites, characterized in that, The steps are as follows: Step 1: Taking into account the input conditions of the micro-nano satellite, including load-bearing capacity, size, mass, mechanical interface, external heat flow and internal heat source, conduct an integrated design of the structural subsystem and thermal control subsystem; Step 2: Design the configuration and layout of micro / nano satellites: 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 in order to achieve the organic integration of the structural subsystem and the thermal control subsystem. Step 3: Based on the interface input file, design the mechanical and thermal interfaces of the micro-nano satellite in parallel; Step 4: Design the heat dissipation method for the micro / nano satellite, including the location and size of the heat dissipation surface; The heat dissipation surface is selected at the part of the micro-nano satellite where the solar radiation absorbed is the least, the Earth radiation and Earth reflection reaching the heat dissipation surface are the least, and the internal heat is concentrated. In addition, the part is selected to have the largest contact area with the individual unit. 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 individual unit inside the micro-nano satellite and the shell is as short as possible. By controlling the shell temperature, the temperature of the individual units inside the satellite can be indirectly controlled. Substitute the external heat flow absorbed by each surface of the micro-nano satellite obtained in step 3, as well as 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 average temperature of each internal unit at the allowable average temperature of each internal unit of the micro-nano satellite. According to the thermal network method, the temperature of the outer shell of the micro-nano satellite does not have a significant gradient. Based on this characteristic, the micro-nano satellite as a whole is regarded as a node. This node only conducts radiative heat exchange to the outside and exchanges heat with the internal heat source through thermal conduction and thermal radiation. Let the expected node temperature be The required heat dissipation area is obtained by iterative solution. : ， ， In the formula: For micro and nano satellites Area of ​​each heat dissipation surface; Power consumption inside the star; For the first The surface infrared emissivity of each heat dissipation surface, where n represents the total number of heat dissipation surfaces; For the first The surface solar radiation absorption rate of each heat dissipation surface; Solar radiation; It reflects Earth's albedo radiation; This refers to Earth's infrared radiation. Infrared radiation from external components; For the first The average solar viewing angle coefficient of the entire surface of the heat dissipation surface; For the first The average Earth's perspective coefficient of the entire surface of the heat dissipation surface. This is the viewing angle coefficient of the satellite relative to external components; To simplify the calculation of the safety factor for the impact of heat leakage; Finally, based on the location of the heat dissipation surface, specific heat dissipation measures are determined; Step 5: Design the isothermal method for the micro / nano satellite and integrate thermal control components into the micro / nano satellite structural subsystem, including thermally conductive materials, surface treatment of structural components, thermal insulation pads, MLI and thermally conductive fillers, to improve thermal control performance.

2. The integrated structural thermal control design method 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 interfaces of microsatellites and nanosatellites include the following: the connection method between the microsatellites and nanosatellites and the separation mechanism, the location of the connection point of the separation mechanism in the input conditions, the material of the positioning pin at the connection point, the power supply method between the microsatellites and nanosatellites and the carrier satellite, the installation location of the limit switches, and the mechanical interfaces between the microsatellites and nanosatellites and other mechanisms. The external heat flow of microsatellites and nanosatellites requires comprehensive consideration of their orbits, attitudes, and thermal boundary conditions. It is necessary to calculate the magnitude of heat flow from solar radiation, Earth's infrared radiation, and Earth's albedo radiation on each of the microsatellite's external surfaces, as well as the influence of heat flow from other spacecraft on the microsatellites and nanosatellites.

3. The integrated structural thermal control design method for micro / nano satellites according to claim 2, characterized in that: The orbital parameters of microsatellites include orbital altitude and orbital inclination, as well as the time of the ascending node; the attitude parameters of microsatellites include the overall coordinate system of microsatellites, the direction of flight in orbit, and the direction of flight to the ground in orbit; based on the flight attitude, the magnitude of the external heat flux incident on each surface of the microsatellite in extreme high temperature and extreme low temperature conditions is calculated, thereby determining the location of the heat dissipation surface and the heat insulation surface of the microsatellite.

4. The integrated structural thermal control design method for micro / nano satellites according to claim 3, characterized in that, In step 1, the size of the internal heat source and the operating temperature range of the internal components of the microsatellite are important parameters that determine the overall temperature condition of the microsatellite. The individual components of the microsatellite are reasonably distributed according to the size of the internal heat source to avoid the concentration of high-power components. The temperature gradient of the microsatellite is determined according to the operating temperature range of the internal components. The structural components of the microsatellite have the widest temperature range, while the battery has the narrowest operating temperature range. Therefore, the design of the battery requires heat insulation and active heating design.

5. The integrated structural thermal control design method for micro / nano satellites according to claim 1, characterized in that, Step 2 involves designing the configuration and layout of the microsatellite, including the design of the main load-bearing structure and the regional layout design of individual units within the microsatellite, as detailed below: Design of the main load-bearing structure for micro / nano satellites: Specifically, this includes: the size envelope design of the main load-bearing structure of the micro-nano satellite, the integrated shell design, the internal reinforcing rib design of the integrated shell, the thickening design at the shell surface connection, and the local thickening design at the installation location of the separation mechanism support. Microsatellite internal single-unit regional layout design: The PCB components are stacked, with the satellite computer, battery control module, GNSS module, and S-tracking and control unit installed separately in different areas. The gyroscope and DC-DC module are installed in an integrated housing. The internal space of the micro-nano satellite is compact and insufficient for a wire-burning structure. The solar array is body-mounted and directly installed on the sun-facing side of the micro-nano satellite. The array area is designed according to the energy balance input requirements. The external antennas, including the GPS antenna and the S-tracking and control antenna, are all body-mounted to facilitate the reduction of the overall size.

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

7. The integrated structural thermal control design method for micro / nano satellites according to claim 6, characterized in that, The thermal interface design of micro-nano satellites includes the use of thermal insulation pads and multi-layered thermal insulation materials to complete the thermal insulation design between mechanical interface mounting interfaces, between the body-mounted solar cell array and the integrated shell, and between other mechanisms and the base plate.

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

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