Deorbiting device

Abstract

A deorbiting device according to an embodiment of the present invention is attached to an object that moves on an orbit in outer space, and causes the object to leave the orbit. The deorbiting device comprises: a deorbiting unit including a resistance force generation part that generates a resistance force against movement of the object on the orbit; a test unit for conducting a prescribed test; and a control part that executes control related to the deorbiting unit and / or the test unit in accordance with a prescribed condition.

Description

Deorbital Device

[0001] The present invention relates to a deorbiting device.

[0002] In the development of spacecraft such as artificial satellites, rockets, and space stations, durability tests of various materials and electronic devices used as components must be conducted in actual space. Various technological developments are also progressing using the space environment, such as the investigation of drug discovery and drug administration methods in a microgravity environment, and crystal growth experiments that lead to higher performance of semiconductors.

[0003] For example, Patent Document 1 describes a space medical device that is mounted on a spacecraft such as an artificial satellite and is capable of conducting medical tests in a space environment where a state of zero gravity or microgravity is continuously maintained.

[0004] Japanese Patent Application Laid-Open No. 2021-19511

[0005] However, spacecraft and other devices used in space are required to have a high level of durability against vibrations and the like that occur during launch and while the spacecraft is in orbit, which can result in enormous costs for various components such as power supplies, communication modules, electrical and mechanical interfaces, etc. Furthermore, in space, the environment, such as gravity, radiation distribution, and atmospheric density, changes depending on the altitude of the orbit, and since spacecraft usually orbit at a constant altitude, if there is a need to conduct tests at various altitudes, tests must be conducted on multiple spacecraft, each at a different orbit, further increasing costs.

[0006] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an apparatus that can be tested at various altitudes in space at low cost.

[0007] A de-orbiting device according to one aspect of the present invention is attached to an object moving in an orbit in outer space and causes the object to de-orbit, and includes a de-orbiting unit having a resistance force generating section that generates resistance to the movement of the object in its orbit, a test unit for conducting predetermined tests, and a control section that controls the de-orbiting unit and / or the test unit in accordance with predetermined conditions.

[0008] According to this aspect, the test unit can also use various devices and components of the orbital departure device attached to the target, eliminating the need to separately attach a test unit to the target, thereby reducing the cost of the test unit. Furthermore, since the altitude of the target gradually decreases when the orbital departure unit attached to the orbital departure device causes the target to depart from orbit, the test unit can perform tests at various altitudes during the departure process.

[0009] According to the present invention, it is possible to provide an apparatus that can be tested at various altitudes in space at low cost.

[0010] Fig. 1 is a schematic diagram showing a state in which the orbital de-orbit device 3 according to the embodiment is mounted on a spacecraft 2. Fig. 2 is a schematic diagram showing another state in which the orbital de-orbit device 3 according to the embodiment is mounted on a spacecraft. Fig. 3 is a block diagram showing an example of the functional configuration of the orbital de-orbit device 3 according to the embodiment. Fig. 4 is a schematic diagram showing an example of the arrangement of the orbital de-orbit unit 4 and the test unit 5 in the orbital de-orbit device 3 according to the embodiment.

[0011] A preferred embodiment of the present invention will be described with reference to the accompanying drawings (in each drawing, the same reference numerals denote the same or similar configurations).

[0012] (1) Introduction So-called space debris (space junk), including spacecraft that continue to fly in orbit even after their missions have ended and fragments of damaged spacecraft, has become a problem. In order to dispose of debris from orbit, a Post Mission Disposal (PMD) method is used, in which a de-orbiting device pre-installed on the spacecraft is activated to remotely de-orbit the spacecraft. By using this de-orbiting device, the debris can leave orbit, gradually descend toward the atmosphere, and be burned up during atmospheric re-entry.

[0013] The deorbital device according to this embodiment includes a test unit for conducting predetermined tests in addition to the deorbital unit. This makes it possible to utilize the PMD (Propulsion Module Deorbit Device) that is expected to be installed on many spacecraft, such as rockets and satellites, in the future as a debris countermeasure, to turn spacecraft that have completed their intended tasks and are to be discarded into platforms for conducting various experiments in space. Furthermore, various tests can be conducted using the test unit at various altitudes during the deorbital process. Furthermore, by utilizing an interface for attaching the deorbital device to the spacecraft, it is possible to omit the interface for the test unit and reduce installation costs.

[0014] (2) Overall Configuration The overall configuration of the orbital de-orbit device 3 according to this embodiment will be described with reference to Figures 1 to 3. Figure 1 is a schematic diagram showing a state in which the orbital de-orbit device 3 according to this embodiment is mounted on a spacecraft 2. Figure 2 is a schematic diagram showing another state in which the orbital de-orbit device 3 according to this embodiment is mounted on a spacecraft. Figure 3 is a block diagram showing an example of the functional configuration of the orbital de-orbit device 3 according to this embodiment.

[0015] 1 to 3, the direction of travel of the spacecraft 2 (the direction of the orbit around the Earth, etc.) is the X-axis, the horizontal direction perpendicular to the X-axis is the Y-axis, and the direction perpendicular to the X-axis and Y-axis is the Z-axis. In particular, the direction of the Z-axis facing away from the Earth (the positive Z-axis direction in FIG. 1) is sometimes referred to as the "zenith direction," and the direction of the Z-axis facing toward the Earth is sometimes referred to as the "geocentric direction."

[0016] The spacecraft 2 moves in an orbit around the Earth or other object in outer space. The spacecraft 2 is not particularly limited as long as it is an object that moves in an orbit, and may include an artificial satellite, a rocket, a space station, or parts of these. The altitude of the orbit is not particularly limited, but may be, for example, about 200 to 1000 km. Furthermore, the spacecraft 2 rotates at various rotational speeds and directions while moving in the orbit. Furthermore, for attitude control of the spacecraft 2, a device such as a reaction wheel that rotates at a predetermined rotational speed around a predetermined rotational axis may be provided.

[0017] The deorbital device 3 is attached to an object such as the spacecraft 2 moving in an orbit in outer space via a predetermined electrical and mechanical interface that is responsible for transmitting and receiving information, power, etc., and for mechanical interaction with the object. The electrical and mechanical interface may be highly durable against vibrations that occur during the launch of the spacecraft 2 and while it is in orbit.

[0018] The de-orbit device 3 is a device for causing an object such as the spacecraft 2 to depart from an orbit. To this end, the de-orbit device 3 is equipped with a de-orbit unit 4. The de-orbit unit 4 is equipped with, for example, a resistance force generating unit that generates resistance to the movement of the spacecraft 2 on the orbit, and causes the spacecraft 2 to depart from the orbit by generating this resistance force. The configuration of the de-orbit unit 4 will be described later.

[0019] The leave-orbit device 3 further includes at least one test unit 5 for conducting predetermined experiments in a microgravity environment in space while attached to an object such as the spacecraft 2 and traveling through space or a similar space. Microgravity refers to the gravitational force an object receives from the Earth and the resultant force of centrifugal force received by the object as it rotates while moving in an orbit, etc., and is a pseudo-gravity that appears to be weaker than the gravity experienced on the Earth's surface. This makes it possible to simulate the gravitational environment on the surface of the Moon or Mars within the test unit 5. The configuration of the test unit 5 will be described later.

[0020] The orbital departure device 3 also includes a control unit 36 ​​, a communication unit 37 , a battery unit 38 , and a power generation unit 39 .

[0021] The control unit 36 ​​performs overall control of the orbital departure device 3. The control unit 36 ​​may be configured as a computer including a processor such as a CPU (Central Processing Unit) and memories such as a RAM (Random Access Memory) and a ROM (Read Only Memory).

[0022] The communication unit 37 has the function of a transmitter and / or receiver and is a communication module for transmitting and receiving communication signals to and from any external device. The communication unit 37 may be configured with an antenna, a communication circuit, etc. The communication unit 37 may receive signals from a ground management device, another spacecraft, another de-orbiting device provided on the spacecraft, etc., and supply the signals to the control unit 36. The communication unit 37 may also transmit signals supplied from the control unit 36 ​​to a ground management device, another spacecraft, another de-orbiting device provided on the spacecraft, etc.

[0023] The battery unit 38 includes a battery capable of holding (accumulating) power to be supplied to the deorbital device 3. In particular, the battery unit 38 may be configured to hold power to supply power to the deorbital unit 4 and / or the test unit 5. The battery unit 38 may also be configured to hold power to supply power to the spacecraft 2. The configuration of the battery included in the battery unit 38 is not particularly limited, and may be, for example, a lithium-ion secondary battery or a fuel cell. By including the battery unit 38 in the deorbital device 3, it is possible to ensure power for the deorbital unit 4 and the test unit 5 even if the battery unit of the spacecraft 2 runs out of power or if a failure occurs in the power supply from the spacecraft 2 to the deorbital device 3. This makes it possible to continue testing by the test unit 5 while the spacecraft 2 is out of orbit.

[0024] The power generation unit 39 generates electric power to be supplied to the deorbital device 3. In particular, the power generation unit 39 may be configured to be able to supply the generated electric power to the deorbital unit 4 and / or the test unit 5. The configuration of the power generation unit 39 is not particularly limited as long as it is capable of generating electric power. For example, the power generation unit 39 may include a thin film for photovoltaic power generation, such as a silicon-based film such as crystalline silicon or amorphous silicon, a compound-based film such as CIS or CdTe, or an organic film such as dye-sensitized or perovskite. The power generation unit 39 may be provided at any location in the deorbital device 3 that can receive light such as sunlight, for example, on the outer surface of the outer shell that houses the deorbital device. In particular, the power generation unit 39 may be provided on at least a portion of the tether 31, as shown in FIGS. 1 to 3 . This makes it possible to effectively utilize the three-dimensional shape formed by the deployed tether 31, thereby improving the power generation efficiency of the power generation unit 39. In addition, if the tether 31 is made of a conductive material as described below, the power generation unit 39 may generate part of the power to be supplied to the orbital departure device 3 based on the current flowing through the tether 31 due to the induced electromotive force.

[0025] (2) De-orbit Unit The de-orbit unit 4 will be described with reference to Figures 1 to 3. The de-orbit unit 4 shown in Figures 1 to 3 includes a tether 31. The tether 31 is an example of a resistance force generator that generates resistance to the movement of the spacecraft 2 on its orbit. The de-orbit unit 4 further includes a storage unit 33, a gas supply unit 34, and an electromagnetic valve 35. When deployed, the tether 31 is configured to be tiltable about the Z-axis with the de-orbit unit 4 as the base point.

[0026] The tether 31 may have an inflatable structure, and is configured, for example, to expand when gas is supplied to the interior from a gas supply unit 34 provided in the orbital departure unit 4, thereby forming a predetermined three-dimensional shape.

[0027] One end of the tether 31 may be configured as a fixed end 31T fixed to the de-orbit unit 4, and the other end may be configured as a free end 31F not fixed to the de-orbit unit 4. The de-orbit unit 4 is configured to be able to store the tether 31 therein during the mission of the spacecraft 2, as shown in FIG. 2 , for example. The de-orbit unit 4 is also configured to be able to release the free end 31F of the tether 31 into space and supply a predetermined gas into the interior of the tether 31 at a predetermined timing, such as when the mission of the spacecraft 2 ends, thereby expanding the tether 31 and deploying it to form a predetermined three-dimensional shape. FIG. 1 shows the tether 31 deployed outside the de-orbit unit 4. Note that although the direction of the tether 31 is drawn parallel to the Z-axis in FIG. 1 , the tether 31 is configured to be able to tilt at a predetermined angle with respect to the Z-axis, with the de-orbit unit 4 as the base point, in response to gravity gradient forces, atmospheric resistance, and the like.

[0028] The tether 31 may be formed of, for example, a flexible thin film member. The material constituting the tether 31 may be one or more of, for example, resin, metal thin film (sputtered or the like), adhesive, carbon fiber reinforced plastic (CFRP), carbon film, etc. Note that the tether 31 may have an overlap portion formed by bonding multiple thin film members together. The overlap portion may also be a region that receives atmospheric resistance.

[0029] The predetermined three-dimensional shape formed by the deployed tether 31 may be a shape capable of withstanding atmospheric resistance to release the spacecraft 2 from orbit. The predetermined three-dimensional shape may be, for example, a three-dimensional shape with high isotropy about the longitudinal direction of the tether 31 (the Z-axis direction in FIG. 1 ). The higher the isotropy about the longitudinal direction of the tether 31 (the Z-axis direction in FIG. 1 ), the smaller the variation in atmospheric resistance experienced when the tether 31 rotates around that axis. Therefore, rotation of the tether about that axis is less likely to occur, the orientation of the tether about the longitudinal direction is stabilized, and it is easier to ensure a projected area for withstanding atmospheric resistance regardless of the orientation about the longitudinal direction. A three-dimensional shape with high isotropy about the longitudinal direction of the tether 31 (the Z-axis direction in FIG. 1 ) may be, for example, a substantially cylindrical shape as shown in FIG. 1 . In this case, the longitudinal dimension of the tether 31 is not particularly limited and may be, for example, in the range of several meters to several kilometers.

[0030] A gravity gradient force may act on the tether 31. Here, the gravity gradient force is a force that acts to orient the attitude of an object in a predetermined direction due to spatial changes in the gravitational acceleration acting on the object. In particular, when an object that revolves around the center of gravity, such as the Earth, has a long shape like the tether 31, the gravity gradient force acts as a force that orients the longitudinal direction toward the center of gravity, that is, a force that reduces the angle between the longitudinal direction and the Z-axis direction.

[0031] The material constituting the tether 31 may include conductive materials such as metal fibers such as aluminum fibers and conductive high-strength fibers. The Lorentz force generated in the tether 31 by movement through the magnetic field in space functions as a resistance force against movement of the spacecraft 2 in orbit in addition to or instead of atmospheric resistance.

[0032] For example, the storage section 33 may be configured to have a space therein capable of storing the tether 31. The manner in which the tether 31 is stored inside the storage section 33 is not particularly limited, but may be, for example, wound as shown in Fig. 3, or folded.

[0033] The gas supply unit 34 may hold a gas to be supplied to the tether 31. The gas supply unit 34 may be configured as, for example, a gas cartridge. The type of gas to be supplied to the tether 31 is not particularly limited, and may be, for example, nitrogen gas.

[0034] The electromagnetic valve 35 may be connected to each of the gas supply unit 34 and the tether 31. The electromagnetic valve 35 may adjust the opening and closing based on a control signal received from the control unit 36, thereby adjusting the amount of gas supplied from the gas supply unit 34 to the tether 31.

[0035] One end 31T of the tether 31 may be configured as a fixed end that is fixed to a predetermined position on the de-orbit unit 4. The end 31T of the tether may be connected to the gas supply unit 34 via an electromagnetic valve 35. The other end 31F of the tether 31 may be configured as a free end that is not fixed to the de-orbit unit 4. The tether 31 may be stored inside the storage unit 33, for example, during a mission of the spacecraft 2.

[0036] (3) Test Unit The test unit 5 will be described with reference to Figures 3 and 4. Figure 4 is a schematic diagram showing an example of the arrangement of the de-orbit unit 4 and the test unit 5 in the de-orbit device 3 according to the embodiment. Note that, for the sake of convenience of explanation, units and members other than the de-orbit unit 4 and the test unit 5 are omitted from Figure 4.

[0037] The test unit 5 is a unit for conducting tests in various fields. The fields are not particularly limited and may include, for example, chemistry, biochemistry, medicine, bioengineering, genetic science, biology, physics, environmental science, earth science, and astronomy. The test unit 5 may be configured, for example, to include various instruments, devices, and other equipment in a sealed or open housing partitioned by a metal material or the like. The instruments and devices included in the test unit 5 are not particularly limited and may include, for example, sensors and measuring devices for detecting gravity, temperature, humidity, etc., analytical devices for analyzing the components and structure of substances, and synthesis devices for synthesizing samples and substances. More specifically, for example, the instruments and devices may include instruments such as petri dishes, lighting devices, temperature control devices, automatic titration devices, chromatography, microscopes, cameras, PCR devices, DNA sequencers, X-ray analysis devices, MRI, spectrophotometers, laser devices, and the like.

[0038] The test unit 5 may include a computer including a processor such as a CPU and memories such as a RAM and a ROM. The computer may control components, devices, etc. within the test unit 5, so that the test of the test unit 5 may be performed automatically.

[0039] The test unit 5 may be configured as, for example, a container that can be easily attached to and detached from the orbital departure device 3. In particular, the orbital departure device 3 may be configured to allow a plurality of test units 5 to be installed therein. This makes it possible to adjust the volume of the internal space of the orbital departure device 3 by installing any number of test units 5 inside the orbital departure device 3. Figure 4 shows, as an example, an example in which four test units 5 are installed in the orbital departure device 3.

[0040] When the de-orbital device 3 includes multiple test units 5, the tools and devices installed inside each test unit 5 may be the same, or some or all of them may be different. FIG. 4 shows, as an example, a configuration in which four test units 5 are installed below the de-orbital device 4. However, the installation positions of the de-orbital unit 4 and the test units 5 are not particularly limited. The de-orbital unit 4 and the test units 5 may be configured to be installable, for example, so that the center of gravity of the de-orbital device 3 is near the center of the de-orbital device 3. This makes it possible, for example, to adjust the weight balance of the entire spacecraft 2 equipped with the de-orbital device 3 by arranging the separate test units 5 at positions away from the de-orbital unit 4, even if the weight balance of the de-orbital device 3 and the spacecraft 2 equipped with the de-orbital device 3 is shifted due to the installation of the de-orbital unit 4.

[0041] Information such as the test content and the environment required for the test (including the temperature, humidity, pressure, and other internal environment of the test unit 5, as well as the magnitude of microgravity) may be set for the test unit 5. This information may be stored in a memory or the like provided in the control unit 36, or may be acquired by the de-orbit device 3 from an external device via the communication unit 37. The control unit 36 ​​may control the test unit 5 based on this information.

[0042] (4) Control of Each Unit Next, the control of each unit of the orbit departure device 3 by the control unit 36 ​​will be described.

[0043] <Predetermined Condition> The control unit 36 ​​may execute control related to the de-orbiting unit 4 and / or the test unit 5 in accordance with a predetermined condition. Here, the predetermined condition may be based on a control signal received from an external device by the communication unit 37. Alternatively, the predetermined condition may be a condition defined by at least one of the movement status information, the departure status information, and the power information.

[0044] The movement status information may be information relating to the status of movement in the orbit of the spacecraft 2. Specifically, the movement status information may include the position, movement distance, movement speed, attitude, rotation speed for attitude control, elapsed time of movement, etc. of the spacecraft 2.

[0045] The departure status information may be information relating to the status of departure from the orbit of the spacecraft 2. Specifically, the departure status information may include the altitude of the spacecraft 2, information relating to the activation of the deorbital unit 4 (whether it has been activated, the time elapsed since activation, the power consumption of the deorbital unit 4, etc.), etc.

[0046] The power information may be information about the power of the spacecraft 2 and / or the de-orbital device 3. Specifically, the power information about the power of the de-orbital device 3 may include information about the power held by the battery unit 38 (remaining power, power reduction rate, voltage value, current value, etc.), and information about the power generated by the power generation unit 39 (power generation capacity, amount of power generated per unit time, etc.). Furthermore, the power information about the power of the spacecraft 2 may include information about the power held by a battery (not shown) provided in the spacecraft 2 (remaining power, power reduction rate, voltage value, current value, etc.), information about the power generated by a power generation unit (not shown) provided in the spacecraft 2 (power generation capacity, amount of power generated per unit time, etc.), etc.

[0047] These various types of information (movement status information, departure status information, power information, etc.) may be stored in a memory provided in the control unit 36, or may be acquired by the orbit departure device 3 from an external device via the communication unit 37.

[0048] The predetermined condition may be defined as a result of comparing at least one of the movement status information, the departure status information, and the power information with a predetermined threshold. Specifically, the predetermined condition may be defined as, for example, "when the movement speed of the spacecraft 2 is equal to or greater than a threshold," "when the altitude of the spacecraft 2 is equal to or less than a threshold," "when the elapsed time since the de-orbit unit 4 was activated is equal to or less than a threshold," "when the power held by the battery unit 38 is equal to or less than a threshold," "when the amount of power generated per unit time by the power generation unit 39 is equal to or greater than a threshold," "when the voltage of the power supplied from the spacecraft 3 to the de-orbit device 3 is equal to or less than a threshold," etc.

[0049] <Control of De-orbit Unit 4> The control unit 36 ​​may execute control related to the de-orbit unit 4 in accordance with, for example, predetermined conditions.

[0050] For example, when a predetermined condition is satisfied, the control unit 36 ​​may control the deorbit unit 4 so that the tether 31 is subjected to atmospheric resistance. The predetermined condition may be satisfied when, for example, the movement status information, the deorbit status information, the power information, or the like becomes equal to or greater than a predetermined threshold value, or when a predetermined signal is received by the communication unit 37 from an external device at a predetermined timing, such as after the spacecraft's mission is completed.

[0051] First, the control unit 36 ​​opens, for example, an opening / closing lid (not shown) provided on the housing unit 33. This puts the tether 31 in a state where it can be released to the outside of the housing unit 33. Then, the control unit 36 ​​controls the opening degree of the electromagnetic valve 35 to supply gas from the gas supply unit 34 to the tether 31. This causes the tether 31 to expand and unfold so as to form a predetermined three-dimensional shape, and puts it in a state where it can receive atmospheric resistance. Due to the atmospheric resistance received by the tether 31, the spacecraft 2 equipped with the orbital departure device 3 gradually loses altitude and eventually leaves the circular orbit.

[0052] The speed at which the tether 31 is deployed by the supply of gas is not particularly limited, but may be, for example, a speed at which it takes several hours to deploy 1 meter, or a speed at which it takes several days to several months to deploy the tether 31. As the deployed tether 31 is subjected to atmospheric resistance, the spacecraft 2 carrying the orbital de-orbit device 3 decelerates, gradually departs from the orbit, and falls towards the atmosphere. The time from the start of de-orbit to the time the spacecraft 2 falls to an altitude at which it re-enters the atmosphere is not particularly limited, but may be several hours, weeks, months, years, decades, etc.

[0053] The deployed length of the tether 31 affects the rotation speed of the orbiting spacecraft 2. Therefore, the control unit 36 ​​may, for example, obtain information on the level of microgravity required by the test unit 5 and the rotation speed of the spacecraft 2, and then adjust the length of the tether 31 to match the level of microgravity required by the test unit 5.

[0054] The control unit 36 ​​may transmit information about the deorbital unit 4 to an external device, for example, via the communication unit 37.

[0055] <Control of Test Unit 5> The control unit 36 ​​may execute control related to the test unit 5 according to, for example, predetermined conditions.

[0056] The content of the control related to the test unit 5 is not particularly limited as long as it relates to the test unit 5, and may include, for example, control of the test environment within the test unit, control of the timing of tests by the test unit, etc. Control of the test environment within the test unit may include, for example, control of the temperature, humidity, and pressure (including the degree of openness of the test unit to the atmosphere) within the test unit. Control of the timing of tests by the test unit may include, for example, starting and stopping the tests. Furthermore, if the de-orbit device 3 includes multiple test units 5, the control unit 36 ​​may control the order of tests by each test unit 5. The control unit 36 ​​may execute control of these test units 5, for example, when a value calculated based on at least the movement status information, de-orbit status information, and power information becomes equal to or smaller than a predetermined threshold. Specifically, the control unit 36 ​​may start or stop testing of the test unit 5, for example, when the altitude of the spacecraft 2 reaches a value set for the test unit 5. Furthermore, the control unit 36 ​​may start testing of the test unit 5, for example, when the de-orbit unit 4 is activated or when the time since activation reaches a predetermined threshold.

[0057] The control unit 36 ​​may transmit information about the test unit 5 to an external device via the communication unit 37, for example.

[0058] <Control of Battery Unit 38> The control unit 36 ​​may execute control related to the battery unit 38 according to, for example, predetermined conditions.

[0059] The control unit 36 ​​may, for example, control the power supplied from the battery unit 38 to the de-orbit unit 4 and / or the power supplied to the test unit 5 according to predetermined conditions. The control unit 36 ​​may acquire information on the power required by the de-orbit unit 4 and the test unit 5, and then allocate at least a portion of the power held in the battery unit 38 to the de-orbit unit 4 and the test unit 5 based on the information. Note that, if the de-orbit device 3 includes a plurality of test units 5, the control unit 36 ​​may further acquire information on the power required by each test unit 5, and then allocate at least a portion of the power held in the battery unit 38 to each test unit 5 based on the information.

[0060] The control unit 36 ​​may execute the supply of power from the battery unit 38, giving priority to either the de-orbit unit 4 or the test unit 5 over the other. In particular, the control unit 36 ​​may execute this control when the power held by the battery unit 38 is less than the required power. For example, the control unit 36 ​​may supply the required power from the battery unit 38 to the de-orbit unit 4 and then supply the remaining power to the test unit 5. This makes it possible to reliably perform de-orbit of the spacecraft 2 by the de-orbit device 3. Alternatively, for example, the control unit 36 ​​may supply the required power from the battery unit 38 to the test unit 5 and then supply the remaining power to the de-orbit unit 4. This makes it possible to reliably perform testing by the test unit 5 included in the de-orbit device 3.

[0061] The control unit 36 ​​may change which of the de-orbital units 4 and the test units 5 receives priority for power supply from the battery unit 38, depending on information (de-orbital status information) related to the status of the de-orbital of the spacecraft 2 leaving the circular orbit. For example, the control unit 36 ​​may change the priority between the de-orbital unit 4 and the test unit 5 depending on whether the altitude of the spacecraft 2, the elapsed time since the de-orbital unit 4 was activated, etc. are equal to or greater than a predetermined threshold. Furthermore, when the de-orbital device 3 includes multiple test units 5, power supply from the battery unit 38 may be executed depending on the priority set for each test unit 5.

[0062] <Control of Power Generation Unit 39> The control unit 36 ​​may execute control related to the power generation unit 39 according to, for example, predetermined conditions.

[0063] The control unit 36 ​​may, for example, control the power supplied from the power generation unit 39 to the de-orbit unit 4 and / or the power supplied to the test unit 5 according to predetermined conditions. The control unit 36 ​​may acquire information on the power required by the de-orbit unit 4 and the test unit 5, and then allocate at least a portion of the power supplied by the power generation unit 39 to the de-orbit unit 4 and the test unit 5 based on the information. Note that, if the de-orbit device 3 is equipped with a plurality of test units 5, the control unit 36 ​​may further acquire information on the power required by each test unit 5, and then allocate at least a portion of the power supplied by the power generation unit 39 to each test unit 5 based on the information.

[0064] The control unit 36 ​​may execute the supply of power from the power generation unit 39, giving priority to either the de-orbit unit 4 or the test unit 5 over the other. In particular, the control unit 36 ​​may execute this control when the power supplied by the power generation unit 39 is less than the required power. For example, the control unit 36 ​​may supply the necessary power from the power generation unit 39 to the de-orbit unit 4 and then supply the remaining power to the test unit 5. This makes it possible to reliably perform de-orbit of the spacecraft 2 by the de-orbit device 3. Alternatively, for example, the control unit 36 ​​may supply the necessary power from the power generation unit 39 to the test unit 5 and then supply the remaining power to the de-orbit unit 4. This makes it possible to reliably perform testing by the test unit 5 included in the de-orbit device 3.

[0065] The control unit 36 ​​may change which of the de-orbital unit 4 and the test unit 5 receives priority for power supply from the power generation unit 39, depending on information (de-orbital status information) related to the status of the de-orbitalization of the spacecraft 2 from its orbit. For example, the control unit 36 ​​may change the priority between the de-orbital unit 4 and the test unit 5 depending on whether the altitude of the spacecraft 2, the elapsed time since the de-orbital unit 4 was activated, etc. are equal to or greater than a predetermined threshold. Furthermore, if the de-orbitalization device 3 includes multiple test units 5, power supply from the power generation unit 39 may be executed depending on the priority set for each test unit 5.

[0066] (5) Modification A slave unit may be provided at the end 31F of the tether 31. The slave unit may be configured, for example, as a sensor for detecting a predetermined parameter. The slave unit may also be configured, for example, as a communication module for transmitting and receiving communication signals to and from any external device, and include an antenna and a communication circuit. The slave unit may also include a processor such as a CPU and memories such as RAM and ROM. The slave unit may, for example, acquire position information of the spacecraft 2 or the slave unit itself, or acquire the deployment status of the tether 31, and transmit and receive this information to and from the control unit 36, a ground management device, or another spacecraft.

[0067] The resistance generating unit included in the deorbital unit 4 is a tether 31 that receives atmospheric resistance as a resistance force against the movement of the spacecraft 2 in the orbit, or a tether 31 that includes a conductive material that generates Lorentz force as the resistance force. However, the resistance generating unit is not limited to the tether 31, and may be a thruster such as a cold gas thruster. In this case, the reaction force generated by the thruster ejecting gas in the direction of movement of the spacecraft 2 becomes the resistance force against the movement of the spacecraft 2 in the orbit. The thruster may also serve as a device that generates thrust for the spacecraft 2 to move in the orbit and a device that controls the attitude of the spacecraft 2. The configuration of the resistance generating unit that receives atmospheric resistance is not limited to an inflatable structure or a tether-shaped one, and may be, for example, cloth-shaped, fan-shaped, umbrella-shaped, or the like, or may be composed of a frame and a sheet.

[0068] The test unit 5 may be installed in an empty space inside the de-orbiting unit 4. Furthermore, if the tether 31 has an inflatable structure, the test unit 5 may be provided inside the tether 31 and configured to be able to perform tests on the movement of gas supplied inside the tether 31 and the movement of floats within the gas.

[0069] The test unit 5 may function as the gas supply unit 34. Specifically, the test unit 5 may be configured to store gas therein and be usable as a gas source for the tether 31 of the inflatable structure.

[0070] The above-described embodiments are intended to facilitate understanding of the present invention and are not intended to limit the present invention. The elements of the embodiments, as well as their arrangement, materials, conditions, shapes, sizes, etc., are not limited to those illustrated and can be modified as appropriate. Furthermore, configurations shown in different embodiments can be partially substituted or combined with each other.

[0071] 2...spacecraft, 3...deorbital device, 31...tether, 31F, 31T...ends, 33...accommodation section, 34...gas supply section, 35...electromagnetic valve, 36...control section, 37...communication section, 38...battery section, 39...power generation section, 4...deorbital unit, 5...test unit

Claims

1. An orbital departure device that is attached to an object moving in an orbit in outer space and causes the object to leave the orbit, comprising: an orbital departure unit having a resistance generating unit that generates resistance to the movement of the object on the orbit; a test unit for performing specified tests; and a control unit that executes control of the orbital departure unit and / or the test unit in accordance with specified conditions.

2. The orbital departure device of claim 1, wherein the specified condition is a condition defined by at least one of: movement status information, which is information regarding the status of the movement of the object in the orbit; departure status information, which is information regarding the status of the departure of the object from the orbit; and power information, which is information regarding the power of the object and / or the orbital departure device that can be supplied to the orbital departure device.

3. The orbital departure device according to claim 1, wherein the control unit controls at least one of the environment within the test unit and the timing of tests performed by the test unit.

4. The orbital departure device according to claim 1, wherein the control unit controls the orbital departure unit so that the resistance force generating unit is in a state in which it generates the resistance force.

5. The orbital departure device according to claim 1, further comprising a transmitting unit that transmits information relating to the specified test performed by the test unit to a specified information processing device.

6. The orbital departure device according to claim 1, wherein the control unit determines whether the resistance generating unit has been activated, and operates the test unit if it determines that the resistance generating unit has been activated.

7. The deorbiting apparatus of claim 1, further comprising a power supply for supplying power to said deorbiting apparatus.

8. The orbital departure apparatus of claim 7, wherein the power supply unit comprises a battery unit that holds power to be supplied to the orbital departure apparatus, and / or a power generation unit that generates power to be supplied to the orbital departure apparatus.

9. The orbital departure device according to claim 8, wherein the control unit controls the power supplied from the battery unit and / or the power generation unit to the orbital departure unit and / or the test unit in accordance with the predetermined conditions.

10. The orbital departure device as described in claim 8, wherein the resistance generating unit is configured to be capable of forming a predetermined three-dimensional shape to receive atmospheric resistance as the resistance force, and the power generating unit is provided in the resistance generating unit.

11. The orbital departure device described in claim 8, wherein the resistance force generating unit is configured to include a conductive material capable of generating a Lorentz force as the resistance force, and the power generating unit generates the power based on a current flowing through the conductive material of the resistance force generating unit.

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