Patent Description:
In recent years, space debris such as an artificial satellite that has become uncontrollable due to a failure or rocket debris has been increasing, and retrieval of space debris has become a problem.

In addition to the increase in space debris, large-scale satellite constellations including hundreds to thousands of satellites have started to be constructed, and the risk of collision accidents in orbit is increasing. Thus, in order to avoid collisions, there has been an appeal for the need for deorbit after completion of a mission in orbit (PMD), or ADR that causes debris such as a failed satellite or an upper stage of a rocket that is floating to deorbit by external means such as a debris retrieval satellite. International discussions have begun as STM on the need for such ADR. PMD is an abbreviation for Post Mission Disposal. ADR is an abbreviation for Active Debris Removal. STM is an abbreviation for Space Traffic Management.

Patent Literature <NUM> discloses a technology to capture space debris that is tumbling or rotating. <CIT> and <CIT> disclose prior art examples of capturing a debris by sandwiching it between two satellites.

In the technology of Patent Literature <NUM>, debris is captured with a rope-shaped object, so that a problem is that it is difficult to determine a center-of-gravity position when debris such as rocket debris or a failed satellite is to be retrieved.

In particular, in order to carry out an active control operation during orbital descent by a debris retrieval satellite connected with debris, it is necessary to place propulsion devices in a plurality of directions so as to sandwich the center-of-gravity position of the debris retrieval satellite connected with the debris. Therefore, for debris such as rocket debris or a failed satellite, it is difficult to place the propulsion devices at appropriate positions. For example, an instrument such as a robot arm that is long enough to wrap around the debris and has a great deal of freedom is required.

An object of the present invention is mainly to provide a debris retrieval system that can retrieve debris unerringly.

A debris retrieval system according to claim <NUM> is provided.

In a debris retrieval system according to the present invention, a control unit generates a control command to capture debris by sandwiching the debris between a first satellite and a second satellite and carry out an active control operation during orbital descent on a flying object which is the first satellite, the debris, and the second satellite being connected together. Then, the control unit transmits the control command to at least one of the first satellite and the second satellite via an apparatus communication device. Therefore, with the debris retrieval control apparatus according to this embodiment, there is an effect that debris can be retrieved unerringly.

Embodiments of the present invention will be described hereinafter with reference to the drawings. Throughout the drawings, the same or corresponding parts are denoted by the same reference signs. In the description of the embodiments, description of the same or corresponding parts will be suitably omitted or simplified. In the drawings hereinafter, the relative sizes of components may be different from actual ones. In the description of the embodiments, directions or positions such as "up", "down", "left", "right", "front", "rear", "top side", and "back side" may be indicated. These terms are used only for convenience of description, and are not intended to limit the placement and orientation of components such as devices, equipment, or parts.

The background to the following embodiments will now be described.

If a mega-constellation satellite or a debris retrieval satellite passes a congested low orbit or the polar region in the process of deorbiting, the risk of a collision becomes disproportionately high. The congested low orbit is, for example, in the vicinity of local standard time (LST) <NUM>:<NUM> or at altitudes of about <NUM> to <NUM>. For such deorbit in which the risk of a collision is disproportionately high, the rules for deorbit actions such as PMD or ADR currently being discussed are insufficient. In the deorbit process before entry into the atmosphere, it is necessary to carry out an active control operation during orbital descent which causes a descent by avoiding areas with disproportionately high risks. Such an active control operation during orbital descent will be referred to as an active deorbit operation. It is possible to avoid a collision by operation control in the deorbit process so as to control the orbital plane, altitude, timing for changing the orbital plane or altitude, and so on.

If only a deorbit action is simply to be performed, the purpose will be achieved by, for example, capturing debris by a debris retrieval satellite using net-like or rope-like capture means and applying deceleration force in a direction opposite to a flying direction.

However, in order to carry out active operation control in the deorbit process, orbit control and attitude control need to be performed on the mass characteristics of two bodies coupled together which are the debris retrieval satellite and the captured debris. Therefore, capture means that is not capable of restraining six degrees of freedom, such as net-like or rope-like capture means, is insufficient.

Even with capture means that is capable of restraining six degrees of freedom, desired orbit control and attitude control cannot be performed unless an injection vector of a propulsion device can be directed appropriately for the mass characteristics of the two bodies coupled together.

When carrying out such an active deorbit operation for debris, the debris retrieval satellite performs orbit control and attitude control with the mass characteristics in the state of being connected with the debris. For such orbit control and attitude control, the propulsion device needs to apply an injection that is vectored to pass through a center-of-gravity position.

In the following embodiments, aspects according to which debris retrieval satellites realize accurate orbit control and attitude control with the mass characteristics in the state of being connected with debris will be described.

The debris retrieval system <NUM> includes a debris retrieval control apparatus <NUM> and the debris retrieval satellite <NUM>. The debris retrieval system <NUM> captures debris <NUM> by sandwiching it between a parent satellite <NUM> and a child satellite <NUM>, and carries out an active control operation during orbital descent, that is, an active deorbit operation on a flying object which is the parent satellite <NUM>, the debris <NUM>, and the child satellite <NUM> being connected together.

Specifically, the debris <NUM> is an object such as an artificial satellite that has become uncontrollable due to a failure or rocket debris. That is, the debris <NUM> is a relatively large object. For example, the debris <NUM> floats at altitudes of <NUM> to <NUM> in an elliptical orbit.

The debris retrieval satellite <NUM> includes the parent satellite <NUM> and the child satellite <NUM>. The parent satellite <NUM> is an example of a first satellite <NUM>. The child satellite <NUM> is an example of a second satellite <NUM>. The debris retrieval control apparatus <NUM> communicates with each of the parent satellite <NUM> and the child satellite <NUM>. The debris retrieval control apparatus <NUM> communicates with the debris retrieval satellite <NUM> via an apparatus communication device <NUM> of the debris retrieval control apparatus <NUM> and a satellite communication device <NUM> of each of the parent satellite <NUM> and the child satellite <NUM>.

In the following description, both or each of the parent satellite <NUM> and the child satellite <NUM> may be referred to as the debris retrieval satellite <NUM>.

The debris retrieval control apparatus <NUM> is a facility located on the ground. The debris retrieval control apparatus <NUM> controls the parent satellite <NUM> and the child satellite <NUM>. For example, the debris retrieval control apparatus <NUM> is composed of a ground station, such as a ground antenna device, a communication device connected to a ground antenna device, or an electronic computer, and a ground facility as a server or terminal connected with the ground station via a network. The debris retrieval control apparatus <NUM> may include a communication device installed in a mobile object such as an airplane, a self-driving vehicle, or a mobile terminal. The debris retrieval control apparatus <NUM> is an apparatus that controls the parent satellite <NUM> and the child satellite <NUM> to retrieve debris such as rocket debris or a failed satellite. The debris retrieval control apparatus <NUM> is referred to also as a ground device or a ground facility.

The debris retrieval control apparatus <NUM> includes a computer. The debris retrieval control apparatus <NUM> includes a processor <NUM>, and also includes other hardware components such as a memory <NUM>, an auxiliary storage device <NUM>, an input interface <NUM>, an output interface <NUM>, and the apparatus communication device <NUM>. The processor <NUM> is connected with other hardware components via signal lines and controls these other hardware components.

The debris retrieval control apparatus <NUM> includes a control unit <NUM> as a functional element. The functions of the control unit <NUM> are realized by hardware or software.

The processor <NUM> is a device that executes a debris retrieval program. The debris retrieval program is a program to realize the functions of the control unit <NUM>.

The processor <NUM> is an integrated circuit (IC) that performs operational processing. Specific examples of the processor <NUM> are a central processing unit (CPU), a digital signal processor (DSP), and a graphics processing unit (GPU).

The memory <NUM> is a storage device to temporarily store data. Specific examples of the memory <NUM> are a static random access memory (SRAM) and a dynamic random access memory (DRAM).

The auxiliary storage device <NUM> is a storage device to store data. A specific example of the auxiliary storage device <NUM> is an HDD. Alternatively, the auxiliary storage device <NUM> may be a portable storage medium, such as an SD (registered trademark) memory card, CF, a NAND flash, a flexible disk, an optical disc, a compact disc, a Blu-ray (registered trademark) disc, or a DVD. HDD is an abbreviation for Hard Disk Drive. SD (registered trademark) is an abbreviation for Secure Digital. CF is an abbreviation for CompactFlash (registered trademark). DVD is an abbreviation for Digital Versatile Disk.

The input interface <NUM> is a port to be connected with an input device, such as a mouse, a keyboard, or a touch panel. Specifically, the input interface <NUM> is a Universal Serial Bus (USB) terminal. The input interface <NUM> may be a port to be connected with a local area network (LAN).

The output interface <NUM> is a port to which a cable of an output device, such as a display, is to be connected. Specifically, the output interface <NUM> is a USB terminal or a High Definition Multimedia Interface (HDMI, registered trademark) terminal. Specifically, the display is a liquid crystal display (LCD).

The apparatus communication device <NUM> has a receiver and a transmitter. Specifically, the apparatus communication device <NUM> is a communication chip or a network interface card (NIC). The debris retrieval control apparatus <NUM> communicates with the debris retrieval satellite <NUM> or other devices via the apparatus communication device <NUM>.

The debris retrieval program is read into the processor <NUM> and executed by the processor <NUM>. The memory <NUM> stores not only the debris retrieval program but also an operating system (OS). The processor <NUM> executes the debris retrieval program while executing the OS. The debris retrieval program and the OS may be stored in the auxiliary storage device <NUM>. The debris retrieval program and the OS that are stored in the auxiliary storage device <NUM> are loaded into the memory <NUM> and executed by the processor <NUM>. Part or the entirety of the debris retrieval program may be embedded in the OS.

The debris retrieval control apparatus <NUM> may include a plurality of processors as an alternative to the processor <NUM>. These processors share the execution of the debris retrieval program. Each of the processors is, like the processor <NUM>, a device that executes the debris retrieval program.

Data, information, signal values, and variable values that are used, processed, or output by the debris retrieval program are stored in the memory <NUM> or the auxiliary storage device <NUM>, or stored in a register or a cache memory in the processor <NUM>.

"Unit" of the control unit <NUM> may be interpreted as "process", "procedure", or "step". "Process" of the control process may be interpreted as "program", "program product", or "computer readable storage medium recording a program".

The debris retrieval program causes a computer to execute each process, each procedure, or each step, where "unit" of the above control unit <NUM> is interpreted as "process", "procedure", or "step". A debris retrieval method is a method performed by execution of the debris retrieval program by the debris retrieval control apparatus <NUM>.

The debris retrieval program may be stored and provided in a computer readable recording medium or storage medium. Alternatively, the debris retrieval program may be provided as a program product.

Referring to <FIG>, a configuration of the parent satellite <NUM> and the child satellite <NUM> according to this embodiment will be described. Each satellite of the parent satellite <NUM> and the child satellite <NUM> will be described as the debris retrieval satellite <NUM> here.

The debris retrieval satellite <NUM> is an artificial satellite. The debris retrieval satellite <NUM> may be an observation satellite or a communications satellite, or may be a satellite produced for the purpose of debris retrieval. The debris retrieval satellite <NUM> includes devices such as the satellite communication device <NUM>, a command data processing device <NUM>, an attitude and orbit control device <NUM>, a propulsion device <NUM>, a capture device <NUM>, and a mission data processing device <NUM>.

The capture device <NUM> is a device to capture the debris <NUM> by sandwiching it between the parent satellite <NUM> and the child satellite <NUM>. The capture device <NUM> may transmit capture data indicating a capture state of the debris <NUM> to the other debris retrieval satellite <NUM> or the debris retrieval control apparatus <NUM>.

The propulsion device <NUM> is a device to change the velocity of the debris retrieval satellite <NUM>. Specifically, the propulsion device <NUM> is a chemical thruster or an electric propulsion thruster. For example, the propulsion device <NUM> is a hydrazine thruster, an ion engine, or a Hall thruster.

The satellite communication device <NUM> is a device to receive a command and transmit capture data. The command is a signal transmitted from the ground and transferred, as data or a control signal, to the attitude and orbit control device <NUM> or the capture device <NUM> via the command data processing device <NUM>. The capture data is data that indicates a capture operation performed by the capture device <NUM> and is transmitted, using the satellite communication device <NUM>, to the ground or a data relay satellite via the mission data processing device <NUM>. For example, the capture data indicates a capture state of the debris <NUM>.

The attitude and orbit control device <NUM> is a device to control attitude elements such as the attitude and angular velocity of the debris retrieval satellite <NUM> and the orientation of the capture device <NUM> and to control orbital elements of the debris retrieval satellite <NUM>. The attitude and orbit control device <NUM> changes the orientation of each attitude element to a desired orientation. Alternatively, the attitude and orbit control device <NUM> maintains each attitude element in a desired orientation. The attitude and orbit control device <NUM> includes an attitude sensor, an actuator, and a controller. Specifically, the attitude sensor is a sensor such as a gyroscope, an Earth sensor, a sun sensor, a star tracker, or a magnetic sensor. The actuator is an instrument such as a momentum wheel, a reaction wheel, or a control moment gyroscope. The controller controls the actuator by executing a control program based on measurement data of the attitude sensor or a control command from Earth.

The attitude and orbit control device <NUM> includes a Global Positioning System receiver (GPSR) and a controller. Specifically, the actuator is an attitude and orbit control thruster. The controller executes a control program based on measurement data of the attitude sensor and the GPSR or a control command from Earth, and performs orbit control by controlling the attitude and the propulsion device <NUM>.

Specifically, the power supply device <NUM> includes equipment such as a solar cell, a battery, and an electric power control device. The power supply device <NUM> provides electric power to each piece of equipment installed in the debris retrieval satellite <NUM>.

A processing circuit of the controller included in the attitude and orbit control device <NUM> will now be described.

The processing circuit may be dedicated hardware, or may be a processor that executes control programs stored in a memory.

In the processing circuit, some functions may be realized by hardware, and the remaining functions may be realized by software or firmware. That is, the processing circuit can be realized by hardware, software, firmware, or a combination of these.

Specifically, the dedicated hardware is a single circuit, a composite circuit, a programmed processor, a parallel-programmed processor, an ASIC, an FPGA, or a combination of these.

ASIC is an abbreviation for Application Specific Integrated Circuit.

FPGA is an abbreviation for Field Programmable Gate Array.

<FIG> is a diagram illustrating a comparison example to be compared with this embodiment.

As illustrated in <FIG>, a debris retrieval satellite <NUM> of the comparison example retrieves debris <NUM> such as an artificial satellite that has lost an orbit control function due to a failure or rocket debris. In <FIG>, the debris retrieval satellite <NUM> of the comparison example captures the debris <NUM> with a capture device, and carries out an active deorbit operation in a state in which the debris retrieval satellite <NUM> and the debris <NUM> are connected. In this case, propulsion devices in a plurality of directions need to be placed so as to sandwich a center-of-gravity position C of the debris retrieval satellite <NUM> and the debris <NUM> being connected together. However, it is difficult with only the debris retrieval satellite <NUM> to place the propulsion devices in the above arrangement.

Referring to <FIG>, operation of the debris retrieval system <NUM> according to this embodiment will be described.

A procedure for the operation of the debris retrieval system <NUM> is equivalent to the debris retrieval method. A program that realizes the operation of the debris retrieval system <NUM> is equivalent to the debris retrieval program.

In step S101, the control unit <NUM> of the debris retrieval control apparatus <NUM> generates a control command <NUM> to be transmitted to at least one of the parent satellite <NUM> and the child satellite <NUM>. The control command <NUM> includes a capture command <NUM> and an orbit control command <NUM>.

The control unit <NUM> generates the capture command <NUM> to capture the debris <NUM> by sandwiching it between the parent satellite <NUM> and the child satellite <NUM>.

<FIG> is a diagram illustrating an example of capture of the debris <NUM> and orbit control by the debris retrieval satellites <NUM> according to this embodiment. As illustrated in <FIG>, an object which is the parent satellite <NUM>, the debris <NUM>, and the child satellite <NUM> being connected together will be referred to as a flying object <NUM>. The control unit <NUM> generates the capture command <NUM> to place the parent satellite <NUM> and the child satellite <NUM> so that a center-of-gravity position C of the flying object <NUM> is on a straight line of a traveling direction vector V of the propulsion device.

The control unit <NUM> generates the orbit control command <NUM> to carry out an active deorbit operation on the flying object <NUM> which is the parent satellite <NUM>, the debris <NUM>, and the child satellite <NUM> being connected together.

In step S102, the control unit <NUM> transmits the control command <NUM> including the capture command <NUM> and the orbit control command <NUM> to at least one of the parent satellite <NUM> and the child satellite <NUM> via the apparatus communication device <NUM>.

The control command <NUM> may be received by the parent satellite <NUM> as a single recipient. Alternatively, the debris retrieval control apparatus <NUM> may generate a control command <NUM> individually for each of the parent satellite <NUM> and the child satellite <NUM> and transmit the control command <NUM> to each.

Mutual communication between the parent satellite <NUM> and the child satellite <NUM> may be performed by non-directional short-range communication. The parent satellite <NUM> and the child satellite <NUM> may be connected at the time of launch and launched simultaneously. Alternatively, the parent satellite <NUM> and the child satellite <NUM> may approach the debris <NUM> after being connected with each other.

In step S103, the debris retrieval satellites <NUM> capture the debris <NUM> based on the control command <NUM> by sandwiching it between the parent satellite <NUM> and the child satellite <NUM>, and carry out the active deorbit operation on the flying object <NUM>. Specifically, the capture devices <NUM> of the parent satellite <NUM> and the child satellite <NUM> capture the debris <NUM> by sandwiching it based on the control command <NUM>. Then, the propulsion devices <NUM> of the parent satellite <NUM> and the child satellite <NUM> carry out the active deorbit operation on the flying object <NUM> based on the control command <NUM>.

As illustrated in <FIG>, each of the parent satellite <NUM> and the child satellite <NUM> is placed so that the center-of-gravity position C of the flying object <NUM> is on a straight line of the traveling direction vector V of the propulsion device.

For example, when rocket debris is to be retrieved, the debris retrieval satellites <NUM> capture the upper end in an axial direction with the parent satellite <NUM> and capture the lower end with the child satellite <NUM>. Then, orbit control and attitude control are performed as the integrated flying object <NUM>.

When it is assumed that the upper end of the debris <NUM> faces toward the traveling direction, an injection in a direction opposite to the traveling direction by the propulsion device of the parent satellite <NUM> causes the flying object <NUM> to decelerate and descend in altitude. By continuing to descend in altitude, the flying object <NUM> will eventually descend to the atmosphere due to the gravity of Earth and burn up as a result of friction with the atmosphere, thereby completing the purpose of debris removal.

<FIG> is a diagram illustrating an example of capture of the debris <NUM> and orbit control by the debris retrieval satellites <NUM> according to this embodiment.

If there is a risk of intrusion into a congested orbit during a descent in altitude, an injection in the traveling direction by the child satellite <NUM> generates an acceleration effect, so that the falling velocity of the flying object <NUM> is reduced.

As illustrated in <FIG> and <FIG>, in the debris retrieval system <NUM>, the velocity of the flying object <NUM> can be increased or decreased by appropriately controlling the operation amount and timing of the propulsion devices <NUM> of the parent satellite <NUM> and the child satellite <NUM>. Specifically, the debris retrieval system <NUM> can speed up the descent before the flying object <NUM> intrudes into the congested orbit so as to cause it to fall before intruding into the congested orbit. Alternatively, the debris retrieval system <NUM> may slow down the descent, and then speed up the descent for falling after the congested orbital plane has rotated and passed away to an orbital plane different from that of the flying object <NUM>. In this way, the debris retrieval system <NUM> carries out the active deorbit operation on the flying object <NUM>.

<FIG> and <FIG> are diagrams illustrating examples of capture of the debris <NUM> and orbit control by the debris retrieval satellites <NUM> according to examples which are not covered by the appended claims.

Orbit control and attitude control of the flying object <NUM> requires not only increasing or decreasing the velocity in the traveling direction but also a movement of the propulsion device <NUM> in a direction orthogonal to the traveling direction, that is, a traveling-direction orthogonal direction, or a movement in a rotation direction.

As illustrated in <FIG>, the flying object <NUM> can accelerate in the traveling-direction orthogonal direction. Specifically, each of the parent satellite <NUM> and the child satellite <NUM> operates the propulsion device <NUM> in the traveling-direction orthogonal direction and in the same direction and with thrust that is inversely proportional to the ratio of the distance from the center of gravity of the flying object <NUM> to each of the propulsion devices <NUM>.

As illustrated in <FIG>, a movement in the rotation direction can be made by causing the propulsion device <NUM> of each of the parent satellite <NUM> and the child satellite <NUM> to make an injection in a direction opposite to each other or to operate with thrust that generates a moment corresponding to the distance from the center of gravity of the flying object <NUM>.

In this embodiment, the functions of the control unit <NUM> are realized by software. As a variation, the functions of the control unit <NUM> may be realized by hardware.

<FIG> is a diagram illustrating a configuration of the debris retrieval system <NUM> according to a variation of this embodiment.

The debris retrieval control apparatus <NUM> includes an electronic circuit <NUM> in place of the processor <NUM>.

The electronic circuit <NUM> is a dedicated electronic circuit that realizes the functions of the control unit <NUM>.

Specifically, the electronic circuit <NUM> is a single circuit, a composite circuit, a programmed processor, a parallel-programmed processor, a logic IC, a GA, an ASIC or an FPGA. GA is an abbreviation for Gate Array.

The functions of the control unit <NUM> may be realized by one electronic circuit, or may be distributed among and realized by a plurality of electronic circuits.

As another variation, some of the functions of the control unit <NUM> may be realized by the electronic circuit, and the rest of the functions may be realized by software.

Each of the processor and the electronic circuit is referred to also as processing circuitry. That is, in the debris retrieval control apparatus <NUM>, the functions of the control unit <NUM> are realized by the processing circuitry.

For debris such as rocket debris or a large satellite that has failed, the center-of-gravity position of a flying object which is a debris retrieval satellite being connected with the captured debris is located far, making it difficult to place propulsion devices. In the debris retrieval system according to this embodiment, even for debris for which it is difficult to place propulsion devices because the center-of-gravity position of a flying object which is a debris retrieval satellite being connected with the captured debris is far, an active deorbit operation can be easily carried out and the debris can be retrieved unerringly.

In the debris retrieval system according to this embodiment, the center-of-gravity position as the flying object after the parent satellite and the child satellite have captured debris is positioned to be on the straight line of the traveling direction vector of the propulsion devices of the parent satellite and the child satellite. Therefore, the debris retrieval system according to this embodiment can accurately perform orbit control and attitude control of the flying object.

The debris retrieval system according to this embodiment can realize the active deorbit operation whose capability has not been explicitly defined in PMD or ADR for performing a deorbit action. That is, the capability for operation control in the deorbit process is provided, and the active deorbit operation can be realized by capturing a non-cooperative target without a dedicated attachment and restraining the six degrees of freedom of the target, and arranging an injection environment for the propulsion devices necessary for performing orbit control and attitude control.

In this embodiment, additions to Embodiment <NUM> will be mainly described. Components that are substantially the same as those in Embodiment <NUM> are denoted by the same reference signs, and description thereof will be omitted.

<FIG> is a diagram illustrating an example of capture of the debris <NUM> by the debris retrieval satellites <NUM> according to this embodiment.

In this embodiment, a capture interface instrument <NUM> is provided in each of the debris retrieval satellites <NUM> and the debris <NUM>.

The capture interface instrument <NUM> is placed so that the center-of-gravity position C of the flying object <NUM> is on the straight line of the traveling direction vector V of the propulsion device <NUM>.

Each of the parent satellite <NUM> and the child satellite <NUM> is provided with the capture interface instrument <NUM> for capturing the debris <NUM>. The debris <NUM> is also provided with a capture interface instrument <NUM> at a position such that the center-of-gravity position C of the flying object <NUM> is on the straight line of the traveling direction vector V of the propulsion device <NUM> when connected with the parent satellite <NUM> and the child satellite <NUM>. The capture interface instrument <NUM> is preferably provided in advance in each of the parent satellite <NUM> and the child satellite <NUM> and in objects that may become debris <NUM> in the future. Specifically, the capture interface instrument <NUM> is preferably provided in advance in each satellite of the parent satellite <NUM> and the child satellite <NUM>, rockets for launching, observation satellites, and communications satellites.

The debris retrieval system according to this embodiment facilitates retrieval of debris such as an artificial satellite or rocket that has completed a mission and a failed artificial satellite.

In this embodiment, additions to Embodiments <NUM> and <NUM> will be mainly described. Components that are substantially the same as those in Embodiments <NUM> and <NUM> are denoted by the same reference signs, and description thereof will be omitted.

In this embodiment, the debris retrieval satellite <NUM> includes a connection device <NUM>.

The connection device <NUM> is included in each of the parent satellite <NUM> and the child satellite <NUM>. The connection device <NUM> includes an arm part <NUM> and a connection part <NUM>.

The arm part <NUM> extends from a body portion of each the parent satellite <NUM> and the child satellite <NUM> toward the other satellite with which the debris <NUM> is sandwiched. That is, the arm part <NUM> extending from the parent satellite <NUM> extends toward the child satellite <NUM>, which is the other satellite. The arm part <NUM> extending from the child satellite <NUM> extends toward the parent satellite <NUM>, which is the other satellite.

The connection part <NUM> is provided at an end portion of the arm part <NUM> and connects with an end portion of the arm part <NUM> of the other satellite. Specifically, the connection part <NUM> is a holding mechanism or a magnet. That is, the connection part <NUM> of the parent satellite <NUM> connects with the connection part <NUM> provided at the end portion of the arm part <NUM> of the child satellite <NUM>. The connection part <NUM> of the child satellite <NUM> connects with the connection part <NUM> provided at the end portion of the arm part <NUM> of the parent satellite <NUM>. That is, the connection devices <NUM> mechanically connect the parent satellite <NUM> and the child satellite <NUM> that are flying with the debris <NUM> being sandwiched between them.

The arm part <NUM> may be provided, for example, in the parent satellite <NUM> so as to wrap around the debris <NUM> and reach the child satellite <NUM>. In this case, the child satellite <NUM> may include only the connection part <NUM>. Alternatively, the configurations of the parent satellite <NUM> and the child satellite <NUM> may be interchanged.

<FIG> is a diagram illustrating an example of the connection device <NUM> according to this embodiment.

As illustrated in <FIG>, three or more connection devices <NUM> may be provided. In <FIG>, three connection devices <NUM> are illustrated. Three or more connection devices <NUM> can be placed to surround a large structure such as a rocket.

The arm part <NUM> may be provided only in the parent satellite <NUM> or may be provided in each of the parent satellite <NUM> and the child satellite <NUM>. The connection device <NUM> may be utilized as a capture device for a large structure such as a rocket by contracting the connection device <NUM> or pulling the child satellite <NUM> from the parent satellite <NUM> as a robot arm after enclosing the large structure.

The debris retrieval system according to this embodiment facilitates capture of debris that is not provided with a structure such as a protrusion suitable for capture. It is also possible to avoid a risk of pushing away and losing debris as a result of failing to capture the debris in orbit.

In Embodiments <NUM> to <NUM> above, each unit of the debris retrieval control apparatus has been described as an independent functional block. However, the configuration of the debris retrieval control apparatus may be different from the configuration in the embodiments described above. The functional blocks of the debris retrieval control apparatus may be arranged in any configuration, provided that the functions described in the above embodiments can be realized. The debris retrieval control apparatus may be one device or may be a system composed of a plurality of devices.

Claim 1:
A debris retrieval system (<NUM>) including a debris retrieval control apparatus (<NUM>) to control retrieval of debris (<NUM>), the debris retrieval system (<NUM>) comprising:
a first satellite (<NUM>);
a second satellite (<NUM>); the debris retrieval control apparatus comprising:
an apparatus communication device (<NUM>) to communicate with at least one of the first satellite (<NUM>) and the second satellite (<NUM>);
a control unit (<NUM>) to generate a control command to capture the debris (<NUM>), the control command controlling the first satellite (<NUM>) and the second satellite (<NUM>) to sandwich the debris (<NUM>) between the first satellite (<NUM>) and the second satellite (<NUM>) such that the first satellite (<NUM>) and the second satellite (<NUM>) are both connected to the debris (<NUM>) and carry out an active control operation during orbital descent on a flying object (<NUM>) which is the first satellite (<NUM>), the debris (<NUM>), and the second satellite (<NUM>) being connected together, and transmit the control command to at least one of the first satellite (<NUM>) and the second satellite (<NUM>) via the apparatus communication device (<NUM>), wherein
the debris (<NUM>) is an artificial satellite or rocket debris,
the debris retrieval control apparatus (<NUM>) is configured to communicate with at least one of the first satellite (<NUM>) and the second satellite (<NUM>),
each of the first satellite (<NUM>) and the second satellite (<NUM>) includes a capture device (<NUM>) to capture the debris (<NUM>) based on the control command and a propulsion device (<NUM>) to carry out the active control operation during orbital descent on the flying object (<NUM>) based on the control command, and
the control unit (<NUM>) is configured to transmit the control command, the control command further controlling the first satellite (<NUM>) and the second satellite (<NUM>) to place the first satellite (<NUM>) and the second satellite (<NUM>) so that a center-of-gravity position of the flying object (<NUM>) is on a straight line of a traveling direction vector of the propulsion devices (<NUM>).