Satellite constellation

Abstract

To enable avoidance of inter-satellite collisions between when artificial satellites deorbit.SOLUTION: When a de-orbiting satellite, which is one among artificial satellites belonging to a first satellite constellation 101, de-orbits from an orbit of a first orbital altitude band and descends, a second satellite constellation 102 ensures an empty orbital region in a second orbital altitude band by expanding a relative angle of any two neighboring orbital planes among a plurality of orbital planes. The de-orbiting satellite passes through the empty orbital region of the second orbital altitude band.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to satellite constellations.

Background Art

[0002] There are increasing plans for satellite megaconstellations in which satellite groups cooperate and operate services at the same nominal orbital altitude, and the total number of satellites is approaching 50,000. In order for these satellite megaconstellations to continue their operations, it is necessary to establish a method of removing satellites that have completed their lifetimes and malfunctioning satellites from orbit, securing free space, and launching successor satellites into orbit. The healthy orbital departure of satellites that have completed their lifetimes is called Post Mission Disposal (PMD). The orbital departure that a malfunctioning satellite cannot perform on its own is called Active Debris Disposal (ADR), and is actively performed using debris removal satellites.

[0003] The process from when a satellite flying at a high altitude leaves its orbit and enters the atmosphere and burns up is called the orbital descent process. In the orbital descent process, since the satellite passes through the orbital altitude band of the megaconstellation satellites flying at a low altitude, there is a risk of collision between satellites. Normally, in a megaconstellation, a plurality of orbital planes are comprehensively and evenly formed in the sky, and a plurality of satellites fly evenly for each orbital plane. Therefore, when an uncontrolled orbital departure occurs, the orbital plane from which the satellite departs and the flying position of the satellite at the time of orbital departure become random, making it difficult to predict which satellite in which lower orbital plane the departing satellite may collide with. Even if it were possible to predict the danger, in an environment where tens of thousands of satellites randomly depart from orbit with the generation change, danger warnings would be issued with an enormous frequency, making it difficult for each satellite to take an avoidance action for each danger warning.

[0004] Patent Document 1 discloses a satellite constellation formation system that avoids collision risk by forming multiple orbital planes with different orbital altitudes. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] International Publication No. 2020 / 158505 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] This disclosure aims to enable the avoidance of collisions between satellites when they deorbit. [Means for solving the problem]

[0007] The satellite constellation disclosed herein is A satellite constellation used as the first satellite constellation in a satellite constellation maintenance method, The method for maintaining the satellite constellation is: The aforementioned first satellite constellation is operated in the first orbital altitude zone, The second satellite constellation operates in a second orbital altitude zone lower than the first orbital altitude zone, forming multiple orbital planes. When a deorbiting satellite, which is one of the satellites belonging to the first satellite constellation, departs from the orbit of the first orbital altitude zone and descends, the second satellite constellation secures an empty orbital area in the second orbital altitude zone by widening the relative angle between any two adjacent orbital planes in the plurality of orbital planes. The deorbiting satellite passes through the empty orbital region of the second orbital altitude zone, A successor satellite, which is a satellite that will replace the de-orbiting satellite, is placed into the orbit in the first orbital altitude zone. It is a method, The aforementioned satellite constellation is The system includes multiple artificial satellites, including the aforementioned deorbiting satellite, The aforementioned deorbiting satellite, Propulsion system and A satellite control device that uses the propulsion system to control the descent speed of the deorbiting satellite in order to allow the deorbiting satellite to pass through the empty orbital region, It is equipped with. [Effects of the Invention]

[0008] According to this disclosure, it is possible to avoid collisions between satellites when they deorbit. [Brief explanation of the drawing]

[0009] [Figure 1] Configuration diagram of the satellite constellation system 100 in Embodiment 1. [Figure 2] Configuration diagram of the artificial satellite 110 in Embodiment 1. [Figure 3] This figure shows the state of the second satellite constellation 102 before deorbiting in Embodiment 1. [Figure 4] This figure shows the state of the second satellite constellation 102 during orbital de-orbit in Embodiment 1. [Figure 5] A diagram showing the state of the deorbiting satellite 103 after it has de-orbited in Embodiment 1. [Figure 6] Configuration diagram of the satellite constellation system 100 in Embodiment 2. [Figure 7] Configuration diagram of the artificial satellite 210 in Embodiment 2. [Modes for carrying out the invention]

[0010] In the embodiments and drawings, the same or corresponding elements are denoted by the same reference numeral. The descriptions of elements denoted by the same reference numeral as the described elements are omitted or simplified as appropriate.

[0011] Embodiment 1. The satellite constellation system 100 will be described based on FIGS. 1 to 5.

[0012] ***Description of the configuration*** Based on FIG. 1, the configuration of the satellite constellation system 100 will be described. The satellite constellation system 100 includes a plurality of satellite constellations. Each satellite constellation is composed of a plurality of artificial satellite groups and forms a plurality of orbital planes. The plurality of artificial satellite groups fly in orbits of different orbital planes in the same orbital altitude band. Each artificial satellite group is composed of a plurality of artificial satellites 110.

[0013] One of the plurality of satellite constellations is referred to as the first satellite constellation 101. The orbital altitude band in which the first satellite constellation 101 operates is referred to as the first orbital altitude band. Each artificial satellite 110 of the first satellite constellation 101 flies in the first orbital altitude band.

[0014] One of the satellite constellations that operates in an orbital altitude band lower than the first orbital altitude band among the plurality of satellite constellations is referred to as the second satellite constellation 102. The orbital altitude band in which the second satellite constellation 102 operates is referred to as the second orbital altitude band. Each artificial satellite 110 of the second satellite constellation 102 flies in the second orbital altitude band.

[0015] The satellite constellation system 100 includes ground facilities 120. The ground facilities 120 include a satellite control device The satellite control system 121 is a computer equipped with hardware such as processing circuits and input / output interfaces. The satellite control system 121 is connected to the communication device 122 via the input / output interfaces. The satellite control system 121 generates various commands for each satellite 110 in order to control each satellite constellation. The communication device 122 communicates with each satellite 110. Specifically, it transmits various commands to each satellite 110.

[0016] Based on Figure 2, the configuration of satellite 110 will be explained. The artificial satellite 110 comprises a propulsion system 111, an attitude control system 112, a satellite control system 113, and a communication system 114. The propulsion device 111 is a device that provides thrust to the satellite 110 and adjusts the speed of the satellite 110. Specifically, the propulsion device 111 is an electric propulsion system. For example, the propulsion device 111 is an ion engine or a Hall thruster. The attitude control device 112 is a device for controlling attitude elements such as the attitude and angular velocity of the satellite 110. The attitude control device 112 changes each attitude element in a desired direction, or maintains each attitude element in a desired direction. The attitude control device 112 comprises attitude sensors, actuators, and a controller. Attitude sensors include gyroscopes, Earth sensors, solar sensors, star trackers, thrusters, and magnetic sensors. Actuators include attitude control thrusters, momentum wheels, reaction wheels, and control moment gyros. The controller controls the actuators according to the measurement data from the attitude sensors or various commands from the ground equipment 120. The satellite control device 113 is a computer equipped with hardware such as processing circuits and input / output interfaces, and controls the artificial satellite 110. The communication system 114 includes a satellite communication device and a ground communication device. The satellite communication device is a communication device for communicating with other artificial satellites 110. The ground communication device is a communication device for communicating with ground facilities 120.

[0017] The processing circuits provided in the satellite control device 113 and the satellite control system 121 will be described below. The processing circuit may be dedicated hardware, or it may be a processor that executes a program stored in memory. In a processing circuit, some functions may be implemented by dedicated hardware, while the remaining functions are implemented by software or firmware. In other words, a processing circuit can be implemented using hardware, software, firmware, or a combination thereof. Dedicated hardware includes, for example, single circuits, complex circuits, programmed processors, parallel programmed processors, ASICs, FPGAs, or combinations thereof. ASIC is an abbreviation for Application Specific Integrated Circuit. FPGA is an abbreviation for Field Programmable Gate Array.

[0018] ***Explanation of operation*** In the satellite constellation system 100, the method for maintaining each satellite constellation is referred to as the satellite constellation maintenance method. The method by which satellite 110 of the first satellite constellation 101 deviates from its orbit in the first orbital altitude zone and descends is called the orbital descent method. The artificial satellite 110 that de-orbits will be referred to as de-orbiting satellite 103. The orbit from which de-orbiting satellite 103 de-orbits will be referred to as the de-orbiting orbit. In the satellite constellation maintenance method, after the orbital descent method is implemented, satellite 110, which will replace satellite 103 that has de-orbited, is placed into a de-orbiting orbit. The satellite 110, which will be placed into a detachment orbit, will be referred to as the successor satellite.

[0019] The orbital descent method will be explained based on Figures 3, 4, and 5. Deorbiting satellite 103 is one of the satellites 110 belonging to the first satellite constellation 101, and it deorbits from its orbit in the first orbital altitude zone and descends. The 12 circles drawn around the Earth represent the 12 orbital planes formed by the second satellite constellation 102. However, the number of orbital planes in the second satellite constellation 102 may be 11 or less, or 13 or more.

[0020] Figure 3 shows the state of the second satellite constellation 102 before satellite 103 de-orbited. The second satellite constellation 102 forms 12 orbital planes, each with a different normal vector direction. In the 12 orbital planes, the angles (relative angles) between adjacent orbital planes are approximately equal. The first orbital plane 104 and the second orbital plane 105 are two adjacent orbital planes.

[0021] Figure 4 shows the state of the second satellite constellation 102 when satellite 103 de-orbits. The second satellite constellation 102 narrows the relative angles of two adjacent orbital planes, except for the relative angle between the first orbital plane 104 and the second orbital plane 105, and widens the relative angle between the first orbital plane 104 and the second orbital plane 105. This ensures that there is space in the second orbital altitude zone for the deorbiting satellite 103 to pass through. The area secured in the second orbital altitude zone is called the empty orbital area.

[0022] Figure 5 shows the deorbiting satellite 103 passing through the empty orbital region in the second orbital altitude zone. The dashed line indicates the path taken by the deorbiting satellite 103. The deorbiting satellite 103 passes through an empty orbital area in the second orbital altitude zone. This allows the deorbiting satellite 103 to safely descend from the second orbital altitude zone.

[0023] After satellite 103 deorbits, a successor satellite will be placed into a deorbital trajectory from the ground or another orbit. This ensures that even if satellite 103 de-orbits, the first satellite constellation 101 will be maintained.

[0024] This explains the orbital derailment of satellite 103. There are two types of orbital derailment: PMD and ADR. PMD is an abbreviation for Post Mission Disposal. ADR is an abbreviation for Active Debris Disposal.

[0025] In PMD, the deorbiting satellite 103 deorbits on its own. Specifically, the satellite control device 113 uses the propulsion device 111 to control the descent velocity of the deorbiting satellite 103 in order to allow it to pass through an empty orbital area. The satellite control device 113 may autonomously perform the control for deorbiting, or it may perform it in accordance with commands from the ground equipment 120.

[0026] In ADR, the deorbiting satellite 103 is deorbited by a removal satellite. In this case, the satellite constellation system 100 is further equipped with a removal satellite. The debris removal satellite is a type of artificial satellite also known as a debris removal satellite. Like satellite 110, the debris removal satellite is equipped with a propulsion system, attitude control system, satellite control system, and communication system. Furthermore, the debris removal satellite is equipped with a capture system. The debris removal satellite operates as follows: First, the satellite control system controls the propulsion system and attitude control system to bring the removal satellite closer to the deorbiting satellite 103. Next, the capture device acquires the deorbiting satellite 103. The satellite control system then uses its propulsion system to control the descent speed of the removal satellite in order to allow the removal satellite to pass through the empty orbital area together with the deorbiting satellite 103. The satellite control system may autonomously perform the control for deorbiting, or it may perform it in accordance with commands from the ground equipment 120.

[0027] This section describes the formation of an empty orbital region in the second satellite constellation, 102. First, the second satellite constellation 102 sequentially changes the orbital altitude of adjacent orbital planes. As a result, the difference in orbital periods of the orbital planes due to the difference in orbital altitude gradually changes the relative angle in the longitude direction of the orbital plane normal vector. This principle creates empty orbital regions. Then, the second satellite constellation 102 restores the orbital altitude of each orbital plane to its original state. As a result, the orbital periods of the orbital planes become the same, and the relative angle in the longitude direction of the orbital plane normal vectors is maintained. In other words, multiple orbital planes are maintained while empty orbital regions are formed. The orbital altitude of satellite 110 is changed by changing the speed of satellite 110. Specifically, when satellite 110 increases its speed, its orbital altitude rises, and when satellite 110 decelerates, its orbital altitude falls. At this time, the satellite control device 113 controls the propulsion system 111 to change the speed of satellite 110. In each satellite 110 of the second satellite constellation 102, the satellite control device 113 may autonomously perform control to form an empty orbital area, or it may perform control according to commands from the ground equipment 120.

[0028] ***Description of the Example*** The satellite constellation system 100 consists of more than 100 artificial satellites 110. The satellite constellation system 100 comprises a constellation of satellites that operate in coordination with each of several nominal orbital altitudes, each of which flies at the same nominal orbital altitude. The nominal orbital altitudes correspond to the first orbital altitude zone and the second orbital altitude zone, respectively. The constellation of satellites corresponds to the first satellite constellation 101 and the second satellite constellation 102, respectively. The method for maintaining the satellite constellation involves deorbiting satellite 110 upon completion of its lifespan or failure to create an empty orbital space, and then placing a successor satellite into orbit. To allow a satellite deorbiting from the high-altitude first satellite constellation 101 to safely pass through the orbital altitude zone of the low-altitude second satellite constellation 102, a large relative angle between orbital planes is set, ensuring an empty orbital area. During this time, the second satellite constellation 102 continues its service operations.

[0029] The deorbiting satellite 103 or the debris removal satellite is equipped with a propulsion system and a deorbiting descent control system. The deorbiting descent control system corresponds to the satellite control system 113 of the deorbiting satellite 103. Then, the deorbiting satellite 103 (and the debris removal satellite) will pass through the empty orbital area set up by the second satellite constellation 102.

[0030] The deorbiting and descent control system predicts the timing (pass-through timing) when the deorbiting satellite 103 will pass through an empty orbital region. Specifically, the detachment and descent control system predicts the time it takes for the detachment satellite 103 to reach the second orbital altitude zone (arrival time) and the angle at which the second satellite constellation 102 revolves in the longitude direction during the arrival time (orbital angle), based on the orbital altitude of the orbital plane in which the detachment satellite 103 flies. Furthermore, the detachment and descent control system predicts the timing of passage based on the arrival time and orbital angle. The detachment and descent control system then operates the propulsion device 111 in accordance with the timing of the detachment, thereby allowing the detachment satellite 103 to pass through an empty orbital area. If the timing of passage differs from the prediction due to prediction errors, the detachment descent control device controls the orbital descent speed by operating the propulsion device 111. The detachment and descent control system may perform control autonomously in orbit, or it may perform control in accordance with commands from ground equipment 120.

[0031] If the first satellite constellation 101 and the second satellite constellation 102 are operated by different operators, the operators of the first satellite constellation 101 and the operators of the second satellite constellation 102 should share information. For example, the operator of the second satellite constellation 102 provides information on available orbital areas to the operator of the first satellite constellation 101. The shared information can be transmitted to each satellite 110 via inter-satellite communication or transmission from ground equipment 120.

[0032] ***Effects of Embodiment 1*** Embodiment 1 provides a method for maintaining a satellite constellation in which a high-altitude deorbiting satellite safely descends to orbit and passes through the orbital altitude of a low-altitude megaconstellation satellite group.

[0033] Typically, a mega-constellation of satellites, consisting of multiple satellites operating services in coordination at their nominal orbital altitudes, employs orbits with similar inclination angles. When satellites with similar orbital inclination angles pass through the altitude zone of the satellite constellation, they can avoid collisions by passing through empty areas in the orbital plane. At the intersection of orbital planes with different normal vectors, there remains a risk of collision with satellites in other orbital planes. However, assuming that a hypothetical group of satellites flies in the hypothetical orbital plane of the second megaconstellation, collisions with satellites in other orbital planes are avoided. In other words, the orbital planes are kept open so that the satellite group of the second megaconstellation can continue operations to avoid collisions within the second megaconstellation, and collisions with satellites in other orbital planes are avoided by having satellites descending to orbit pass at the same time as the hypothetical satellites pass. If multiple satellite megaconstellations with different orbital altitudes are managed by the same operator, the orbital information of high-altitude deorbiting satellites and the available orbital areas at the orbital altitudes of low-altitude megaconstellation satellites can be known in advance. Therefore, it becomes possible to plan and execute safe deorbiting operations systematically. When multiple generating megaconstellations with different orbital altitudes are managed by multiple operators, the operator managing the second satellite megaconstellation can share information with the operator managing the first satellite megaconstellation, and the descending satellites can pass through empty orbital areas to avoid collisions with satellites in other orbital planes. This also reduces the risk of the descending satellites colliding at random locations in random orbital planes, and the frequency of danger warnings being issued decreases. As a result, the second satellite megaconstellation does not need to interrupt its service operations to take hazard avoidance actions.

[0034] One company has a plan to deploy approximately 2,500 megaconstellation satellites at each of three orbital altitudes around 340 kilometers, and several thousand more megaconstellation satellites at orbital altitudes of 550 kilometers and 1,050 kilometers. This plan requires that satellites at orbital altitudes of 550 kilometers or 1050 kilometers avoid collisions as they descend and pass through three orbital altitudes near 340 kilometers. Furthermore, even within the altitude range near 340 kilometers, higher-altitude satellites must descend without colliding with lower-altitude satellites. These megaconstellation satellites employ similar inclined orbits. For such a satellite constellation system, the satellite constellation maintenance method of Embodiment 1 has the effect of avoiding collisions by allowing satellites to pass through empty areas in the orbital plane when they pass through the altitude zone of the satellite group at similar orbital angles.

[0035] Embodiment 1 is an example of a preferred embodiment and is not intended to limit the technical scope of the present disclosure. Embodiment 1 may be implemented in part or in combination with other embodiments.

[0036] Embodiment 2. The configuration in which satellite 210 generates and transmits commands to each satellite 110 will be explained, with the main differences from Embodiment 1, based on Figures 6 and 7.

[0037] ***Explanation of the structure*** Based on Figure 6, the configuration of the satellite constellation system 100 will be explained. The satellite constellation system 100 comprises 210 artificial satellites. Satellite 210 is either Satellite 110 belonging to the first satellite constellation 101, Satellite 110 belonging to the second satellite constellation 102, or another satellite. For example, Satellite 210 is either Satellite 103 (which has de-orbited) or a successor satellite. Satellite 110 belonging to the first satellite constellation 101 and satellite 110 belonging to the second satellite constellation 102 may each be satellite 210.

[0038] Based on Figure 7, the configuration of satellite 210 will be explained. The artificial satellite 210 comprises a propulsion system 211, an attitude control system 212, a satellite control system 213, a communication system 214, an edge server 215, and a computer 216.

[0039] The propulsion device 211 corresponds to the propulsion device 111. The attitude control device 212 corresponds to the attitude control device 112. The satellite control device 213 corresponds to the satellite control device 113. Communication system 214 corresponds to communication system 114. In other words, communication system 214 includes communication equipment such as satellite communication equipment and ground communication equipment.

[0040] The edge server 215 is a computer equipped with processing circuits, input / output interfaces, and a database. The database contains orbital information for both satellite 110 belonging to the first satellite constellation 101 and satellite 110 belonging to the second satellite constellation 102.

[0041] Computer 216 is a computer equipped with processing circuits and a database.

[0042] ***Explanation of operation*** Computer 216 uses artificial intelligence (AI) to generate commands for controlling any satellite 110 by referring to the database of the edge server 215. Any satellite 110 may be the user's own satellite 110. The communication system 214 transmits the generated command to each satellite 110. The command may be transmitted directly to the destination satellite 110, or it may be transmitted to the destination satellite 110 via another satellite 110 or ground equipment 120.

[0043] The following command will be generated and sent. Computer 216 generates commands to control each satellite 110 of the second satellite constellation 102 in order to secure an empty orbital area in the second orbital altitude zone. The communication system 214 transmits the generated command to each satellite 110 of the second satellite constellation 102.

[0044] Computer 216 generates commands to control the deorbiting satellite 103 in order to move it out of the orbit in the first orbital altitude zone and through the empty area in the second orbital altitude zone. The communication system 214 transmits the generated command to the deorbiting satellite 103.

[0045] Computer 216 generates commands to control the trailing satellite in order to place it into orbit in the first orbital altitude zone. The communication system 214 transmits the generated command to the following satellite.

[0046] ***Effects of Embodiment 2*** Satellite 210 is equipped with an edge server 215 and AI to realize a method for maintaining a satellite constellation. By storing the orbital information of the 110 satellites that make up the satellite constellation in the edge server 215, it becomes possible to update the orbital information onboard.

[0047] When inserting a backup satellite into orbit to fill a gap in the orbit, it is necessary to generate safe control commands based on past insertion experience to prevent accidental collisions during the insertion process. Therefore, AI is used to machine-learn commands for successful orbit insertions in the past. This ensures safe orbit insertion. Furthermore, the automation of command generation reduces the workload of ground operations.

[0048] ***Supplement to Embodiment 2*** Edge computing, which involves deploying edge servers on the IoT side, is attracting attention as a method for realizing a distributed architecture. IoT is an abbreviation for Internet of Things. In conventional IoT systems, a centralized system was common where data collected by sensors was transmitted to the cloud via the internet for data analysis. In contrast, edge computing employs a mechanism that distributes data processing either on the device itself or on edge servers located between the device and the cloud. This enables real-time and low-load data processing. Furthermore, with the advancement of the information society and the increase in the amount of information, measures to reduce power consumption and dissipate heat have become challenges. In particular, measures for supercomputers and large-scale data centers in centralized systems are a serious problem. On the other hand, in outer space, heat can be released into deep space through radiative cooling. Therefore, the following mechanism is rational: Treat satellites as devices in the Internet of Things (IoT), and place edge servers on the satellite constellation side. Then, after performing distributed computing processing in orbit, transmit only the necessary data to the ground.

[0049] Artificial intelligence (AI) learns the deviation of intersections (e.g., the maximum deviation) based on past intersections between its own orbital plane and each other's orbital planes. Then, computer 216 detects the collision risk using the AI ​​after machine learning. Specifically, computer 216 detects that there is a satellite that will pass within the deviation range centered on the intersection at a future time when its own satellite will pass the intersection.

[0050] The edge server 215 and the AI-equipped satellite 210 may consist of one satellite or two or more satellites. All satellites may also be satellites 210. Information from all satellites is shared via a communication line and analyzed using a common algorithm, enabling multiple satellites to cooperate while making independent, autonomous decisions. The edge server 215 and the artificial satellite 210 equipped with AI may autonomously generate and execute commands for themselves. Satellites that are not performing their satellite functions may be identified by ground equipment 120, and identification information may be transmitted from ground equipment 120. Anomalies may be detected in orbit based on telemetry information.

[0051] ***Summary of Embodiment 2*** The size of megaconstellations is rapidly increasing, with a total of approximately 50,000 satellites. Therefore, it is urgent to establish a method for satellites that deorbit during generational changes to pass through the orbital altitude of the megaconstellation without colliding with other satellites. In Embodiment 2, the following orbital de-orbiting control is implemented. Through orbital de-orbiting control, the low-altitude megaconstellation secures an empty orbital area, and the de-orbiting satellite of the high-altitude megaconstellation passes through the empty orbital area. To this end, the satellites autonomously transmit commands to the de-orbiting satellites and the operational satellites using AI in space.

[0052] The satellite will be equipped with edge servers and AI computers. The edge server stores a database containing orbital information of the satellites (including its own satellite) that make up the satellite constellation (especially the second satellite constellation). The AI ​​computer references the database on the edge server to generate commands to control any of the satellites that make up the satellite constellation.

[0053] The satellite operates using edge servers and AI computers as follows: The satellite generates a command to secure an empty orbital area in the second orbital altitude zone and transmits the generated command to the satellites of the second satellite constellation.

[0054] The satellite generates a command to deorbit and transmits the generated command to the deorbiting satellite.

[0055] The artificial satellite generates a command to place the following satellite into orbit in the first orbital altitude zone, and then transmits the generated command to the following satellite.

[0056] The satellites will form a second satellite constellation, securing an empty orbital area in the second orbital altitude zone.

[0057] The satellite is a deorbiting satellite and autonomously secures an empty orbital area in the second orbital altitude zone.

[0058] The artificial satellite is a follow-up satellite and secures an empty orbital area in the second orbital altitude zone. [Explanation of symbols]

[0059] 100 Satellite constellation system, 101 First satellite constellation, 102 Second satellite constellation, 103 Deorbiting satellite, 104 First orbital plane, 105 Second orbital plane, 110 Artificial satellite, 111 Propulsion system, 112 Attitude control system, 113 Satellite control system, 114 Communication system, 120 Ground equipment, 121 Satellite control system, 122 Communication equipment, 210 Artificial satellite, 211 Propulsion system, 212 Attitude control system, 213 Satellite control system, 214 Communication system, 215 Edge server, 216 Computer.

Claims

1. A satellite constellation used as the first satellite constellation in a satellite constellation maintenance method, The method for maintaining the satellite constellation is: The aforementioned first satellite constellation is operated in the first orbital altitude zone, The second satellite constellation operates in a second orbital altitude zone lower than the first orbital altitude zone, forming multiple orbital planes. When a deorbiting satellite, which is one of the satellites belonging to the first satellite constellation, departs from the orbit of the first orbital altitude zone and descends, the second satellite constellation secures an empty orbital area in the second orbital altitude zone by widening the relative angle between any two adjacent orbital planes in the plurality of orbital planes. The deorbiting satellite passes through the empty orbital region of the second orbital altitude zone, A successor satellite, which is a satellite that will replace the de-orbiting satellite, is placed into the orbit in the first orbital altitude zone. It is a method, The aforementioned satellite constellation is The system includes multiple artificial satellites, including the aforementioned deorbiting satellite, The aforementioned deorbiting satellite, Propulsion system and A satellite control device that uses the propulsion system to control the descent speed of the deorbiting satellite in order to allow the deorbiting satellite to pass through the empty orbital region, Equipped with, The satellite control device operates autonomously to ensure that when the deorbiting satellite passes through the second orbital altitude zone at an orbital inclination angle similar to the orbital inclination angles of each of the two orbital planes, the deorbiting satellite passes through the empty orbital region secured between the two orbital planes to avoid a collision between the deorbiting satellite and the satellites in the second orbital altitude zone. Satellite constellation.

2. The satellite control device predicts the timing at which the deorbiting satellite will pass through the empty orbital area, and operates the propulsion system in accordance with that timing to allow the deorbiting satellite to pass through the empty orbital area. The satellite constellation according to claim 1.

3. The satellite control device predicts the time it takes for the deorbiting satellite to reach the second orbital altitude zone based on the first orbital altitude zone in which the deorbiting satellite is flying, and predicts the timing of its passage based on the time it takes to reach the second orbital altitude zone. The satellite constellation according to claim 2.

4. The satellite control device predicts the orbital angle, which is the angle at which the second satellite constellation revolves in the longitude direction during the arrival time, and predicts the passage timing based on the arrival time and the orbital angle. The satellite constellation according to claim 3.

5. The satellite control device controls the descent velocity of the deorbiting satellite by activating the propulsion system when the passing timing differs from the prediction. A satellite constellation according to any one of claims 2 to 4.

6. A satellite constellation used as the first satellite constellation in the orbital descent method, The aforementioned orbital descent method is, The aforementioned first satellite constellation is operated in the first orbital altitude zone, The second satellite constellation operates in a second orbital altitude zone lower than the first orbital altitude zone, forming multiple orbital planes. When a deorbiting satellite, which is one of the satellites belonging to the first satellite constellation, departs from the orbit of the first orbital altitude zone and descends, the second satellite constellation secures an empty orbital area in the second orbital altitude zone by widening the relative angle between any two adjacent orbital planes in the plurality of orbital planes. The deorbiting satellite passes through the empty orbital region of the second orbital altitude zone. It is a method, The aforementioned satellite constellation is The system includes multiple artificial satellites, including the aforementioned deorbiting satellite, The aforementioned deorbiting satellite, Propulsion system and A satellite control device that uses the propulsion system to control the descent speed of the deorbiting satellite in order to allow the deorbiting satellite to pass through the empty orbital region, Equipped with, The satellite control device operates autonomously to ensure that when the deorbiting satellite passes through the second orbital altitude zone at an orbital inclination angle similar to the orbital inclination angles of each of the two orbital planes, the deorbiting satellite passes through the empty orbital region secured between the two orbital planes to avoid a collision between the deorbiting satellite and the satellites in the second orbital altitude zone. Satellite constellation.

7. The satellite control device predicts the timing at which the deorbiting satellite will pass through the empty orbital area, and operates the propulsion system in accordance with that timing to allow the deorbiting satellite to pass through the empty orbital area. The satellite constellation according to claim 6.

8. The satellite control device predicts the time it takes for the deorbiting satellite to reach the second orbital altitude zone based on the first orbital altitude zone in which the deorbiting satellite is flying, and predicts the timing of its passage based on the time it takes to reach the second orbital altitude zone. The satellite constellation according to claim 7.

9. The satellite control device predicts the orbital angle, which is the angle at which the second satellite constellation revolves in the longitude direction during the arrival time, and predicts the passage timing based on the arrival time and the orbital angle. The satellite constellation according to claim 8.

10. The satellite control device controls the descent velocity of the deorbiting satellite by activating the propulsion system when the passing timing differs from the prediction. A satellite constellation according to any one of claims 7 to 9.

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