Space communication systems, space communication equipment, space communication methods, and space communication programs

Abstract

The data contained in packets conforming to space communications standards is processed on a network conforming to the CAN or CAN FD standards. [Solution] The space communication system comprises a first space communication device and a second space communication device. The first space communication device acquires a first packet in accordance with a first standard used in space communication. The first space communication device stores the divided data, obtained by dividing the data contained in the acquired first packet, into a frame in accordance with a second standard which is the CAN or CAN FD standard, and transmits it to the second space communication device. The second space communication device combines the multiple divided data contained in each of the multiple frames received from the first space communication device to restore the data.

Description

Technical Field

[0001] The present disclosure relates to a space communication system, a space communication apparatus, a space communication method, and a space communication program.

Background Art

[0002] Spacecraft such as artificial satellites communicate with other spacecraft or the like in accordance with standards established by organizations such as the Consultative Committee for Space Data Systems (CCSDS).

[0003] For example, a spacecraft communicates with other spacecraft or the like by using, as an end-to-end protocol for space communication, the space packet protocol that was standardized at the Consultative Committee for Space Data Systems, which is described in SPACE PACKET PROTOCOL, June 2020, [online], CCSDS, [retrieved on February 25, 2025], Internet, <URL:https: / / public.ccsds.org / Pubs / 133x0b2e2.pdf> (Non-Patent Document 1). For example, data is transmitted and received between spacecraft, and between a spacecraft and a ground station, using space packets conforming to the space packet protocol.

Prior Art Documents

Non-Patent Documents

[0004]

Non-Patent Document 1

Summary of Invention

Problem to be Solved by the Invention

[0005] There are no standardized communication protocols for onboard subnetworks, such as networks within spacecraft. For example, the Space Data Systems Advisory Committee recommends adopting standards such as MIL-STD-1553B, SpaceWire, Wireless, and CAN (Controller Area Network) as communication protocols for onboard subnetworks.

[0006] In the future, if spacecraft are mass-produced, CAN or CAN FD (CAN with Flexible Data-Rate), which are used in mass-produced vehicles and other products, may be adopted as the communication standard for onboard subnetworks.

[0007] Here, the maximum data length of a space packet is 65,542 bytes. On the other hand, the maximum data length of a data field in a frame conforming to the CAN standard is 8 bytes. Therefore, a technology capable of processing data contained in space packets is desired in onboard subnetworks conforming to the CAN or CAN FD standard.

[0008] This disclosure was made to solve the aforementioned problems, and its purpose is to provide a space communication system, space communication device, space communication method, and space communication program capable of processing data contained in packets conforming to space communication standards on a network conforming to CAN or CAN FD standards. [Means for solving the problem]

[0009] The space communication system of this disclosure comprises a first space communication device and a second space communication device, wherein the first space communication device acquires a first packet in accordance with a first standard used in space communication, the first space communication device stores the divided data obtained from the acquired first packet into a frame in accordance with a second standard which is a CAN or CAN FD standard and transmits it to the second space communication device, and the second space communication device combines the multiple divided data contained in each of the multiple frames received from the first space communication device to restore the data.

[0010] One aspect of this disclosure can be realized not only as a space communication system equipped with such characteristic processing units, but also as a semiconductor integrated circuit that realizes part or all of the space communication system. [Effects of the Invention]

[0011] According to this disclosure, data contained in packets conforming to space communications standards can be processed in a network conforming to the CAN or CAN FD standards. [Brief explanation of the drawing]

[0012] [Figure 1] Figure 1 shows an example of the configuration of a space communication system according to an embodiment of the present disclosure. [Figure 2] Figure 2 shows an example of the configuration of a spacecraft according to an embodiment of the present disclosure. [Figure 3] Figure 3 shows an example of the configuration of a space communication device according to an embodiment of the present disclosure. [Figure 4] Figure 4 shows an example of a CAN-MA packet transmitted by a space communication device according to an embodiment of the present disclosure. [Figure 5] Figure 5 is a diagram illustrating the frame creation process by a space communication device according to an embodiment of the present disclosure. [Figure 6] Figure 6 shows an example of a CAN frame transmitted by a space communication device according to an embodiment of the present disclosure. [Figure 7] FIG. 7 is a diagram illustrating an example of a format of a DAT field in a CAN frame transmitted by a data transmission apparatus according to an embodiment of the present disclosure. [Figure 8] FIG. 8 is a diagram illustrating another example of a configuration of a space communication apparatus according to an embodiment of the present disclosure. [Figure 9] FIG. 9 is a flowchart defining an example of an operation procedure when a data transmission apparatus according to an embodiment of the present disclosure performs processing for transmitting a CAN frame. [Figure 10] FIG. 10 is a flowchart defining an example of an operation procedure when a data transmission apparatus according to an embodiment of the present disclosure performs processing for transmitting a CAN frame. [Figure 11] FIG. 11 is a flowchart defining an example of an operation procedure when a data reception apparatus according to an embodiment of the present disclosure performs restoration processing. [Figure 12] FIG. 12 is a flowchart defining an example of an operation procedure when a data reception apparatus according to an embodiment of the present disclosure performs restoration processing. [Figure 13] FIG. 13 is a diagram illustrating an example of a processing sequence of a data transmission apparatus and a data reception apparatus in a space communication system according to an embodiment of the present disclosure. [Figure 14] FIG. 14 is a diagram for explaining priorities set in commands and replies transmitted and received by Modification 1 of the space communication apparatus according to an embodiment of the present disclosure. [Figure 15] FIG. 15 is a diagram illustrating an example of a format of a DAT field in a CAN frame transmitted by Modification 2 of the data transmission apparatus according to an embodiment of the present disclosure. [Figure 16] FIG. 16 is a diagram illustrating an example of a format of a DAT field in a CAN frame transmitted by Modification 3 of the data transmission apparatus according to an embodiment of the present disclosure. [Figure 17] FIG. 17 is a diagram illustrating an example of a format of a DAT field in a CAN frame transmitted by Modification 3 of the data transmission apparatus according to an embodiment of the present disclosure. [Figure 18]FIG. 18 is a diagram illustrating an example of a format of a DAT field in a CAN frame transmitted by Modification 3 of the data transmission apparatus according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0013] First, the content of embodiments of the present disclosure will be listed and described. (1) A space communication system according to an embodiment of the present disclosure includes a first space communication device and a second space communication device, wherein the first space communication device acquires a first packet conforming to a first standard used in space communication; the first space communication device stores divided data obtained by dividing data included in the acquired first packet into frames conforming to a second standard which is a CAN or CAN FD standard, and transmits the frames to the second space communication device; and the second space communication device combines the plurality of pieces of divided data respectively included in the plurality of frames received from the first space communication device to restore the data.

[0014] A data length of a packet conforming to a space communication standard is larger than a data length of a data field in a frame conforming to a CAN or CAN FD standard. As described above, with the configuration in which divided data obtained by dividing data included in the packet is stored in the frame and transmitted, the data can be more reliably transmitted to the counterpart space communication device. In addition, with the configuration in which, at the destination space communication device of the frames, the plurality of pieces of divided data respectively included in the plurality of received frames are combined to restore the data, various processes can be performed using the restored data. Therefore, data included in a packet conforming to a space communication standard can be processed in a network conforming to a CAN or CAN FD standard.

[0015] (2) In the above (1), the first space communication device may create a second packet which includes a header indicating the type of data, the data, and a CRC code, and which conforms to a third standard different from the first standard and the second standard, and the first space communication device may divide the created second packet and store it in the frame.

[0016] With this configuration, the space communication equipment receiving the frame can determine the type of data contained in the frame and perform error detection on the data using a CRC code.

[0017] (3) In (1) or (2) above, the first space communication device may create a second packet which includes the data and conforms to a third standard which is different from the first and second standards, and the second packet may further include information indicating that it requests the writing of the data to the memory of the second space communication device, or information indicating that the data requested by the second space communication device has been read from the memory of the first space communication device, and the first space communication device may divide the created second packet and store it in the frame.

[0018] This configuration makes it easy for the space communication equipment at the destination of the frame to understand what needs to be done with the recovered data.

[0019] (4) In any of (1) to (3) above, the first space communication device may transmit to the second space communication device a frame containing data which is divided data that is different from the data contained in the first packet, in addition to the divided data.

[0020] This configuration allows for the efficient transmission of various types of data in a network conforming to the CAN or CAN FD standard, by mixing data contained in packets conforming to space communication standards with other data.

[0021] (5) In (2) or (3) above, the first space communication device may further acquire a third packet which conforms to a fourth standard used in space communications and which is different from the first standard, and the first space communication device may create a second packet which further includes the data contained in the third packet in addition to the data contained in the first packet.

[0022] This configuration allows for the transmission of multiple types of data corresponding to various space communication standards, enabling efficient transmission of multiple data types that support space communication standards.

[0023] (6) The space communication device according to the embodiment of the present disclosure includes an acquisition unit that acquires packets in accordance with a first standard used in space communication, a creation unit that creates a frame in accordance with a second standard which is a CAN or CAN FD standard, which includes divided data obtained by dividing the data contained in the packets acquired by the acquisition unit, and transmits the frame created by the creation unit to another device.

[0024] The data length of a packet conforming to space communication standards is greater than the data length of the data field in a frame conforming to CAN or CAN FD standards. As described above, by configuring the system to divide the data contained in the packet, store the divided data in the frame, and transmit it, the data can be transmitted more reliably to the space communication equipment of the communication partner. Therefore, the data contained in a packet conforming to space communication standards can be processed in a network conforming to CAN or CAN FD standards.

[0025] (7) An embodiment of the space communication device according to the present disclosure is a space communication device used in a space communication system, comprising: a receiving unit that receives from another space communication device a frame that conforms to the CAN or CAN FD standard and stores segmented data obtained by dividing data contained in a packet used in space communication; and a restoring unit that combines a plurality of segmented data contained in each of the plurality of frames received by the receiving unit to restore the data.

[0026] The data length of a packet conforming to space communication standards is greater than the data length of a data field in a frame conforming to CAN or CAN FD standards. As described above, by receiving a frame containing segmented data obtained by dividing the data contained in the packet, and combining the segmented data contained in each of the received frames to reconstruct the data, various processing can be performed using the reconstructed data. Therefore, data contained in a packet conforming to space communication standards can be processed in a network conforming to CAN or CAN FD standards.

[0027] (8) An embodiment of the space communication method according to the present disclosure is a space communication method in a space communication system comprising a first space communication device and a second space communication device, the first space communication device acquiring a first packet in accordance with a first standard used in space communication; the first space communication device storing divided data, which is the data contained in the acquired first packet, into a frame in accordance with a second standard which is the CAN or CAN FD standard, and transmitting it to the second space communication device; and the second space communication device combining a plurality of divided data contained in a plurality of frames received from the first space communication device to restore the data.

[0028] The data length of a packet conforming to space communication standards is greater than the data length of a data field in a frame conforming to CAN or CAN FD standards. As described above, by dividing the data contained in the packet and storing the divided data in the frame before transmission, the data can be transmitted more reliably to the space communication equipment of the communication partner. Furthermore, at the space communication equipment receiving the frame, various processing can be performed using the reconstructed data by combining the multiple divided data contained in each of the received frames. Therefore, data contained in a packet conforming to space communication standards can be processed in a network conforming to CAN or CAN FD standards.

[0029] (9) The space communication program according to the embodiment of the present disclosure is a space communication program used in a space communication device, which causes a computer to function as an acquisition unit that acquires packets in accordance with a first standard used in space communication, and a transmission unit that stores the divided data obtained from the packets acquired by the acquisition unit into a frame in accordance with a second standard which is the CAN or CAN FD standard, and transmits it to another device.

[0030] The data length of a packet conforming to space communication standards is greater than the data length of the data field in a frame conforming to CAN or CAN FD standards. As described above, by configuring the system to divide the data contained in the packet, store the divided data in the frame, and transmit it, the data can be transmitted more reliably to the space communication equipment of the communication partner. Therefore, the data contained in a packet conforming to space communication standards can be processed in a network conforming to CAN or CAN FD standards.

[0031] (10) The space communication program according to the embodiment of the present disclosure is a space communication program used in a space communication device used in a space communication system, and is a program that causes a computer to function as a receiving unit that receives frames from other space communication devices, which are frames conforming to the CAN or CAN FD standard, and which store divided data obtained by dividing the data contained in packets used in space communication; and a restoring unit that combines a plurality of the divided data contained in each of the plurality of frames received by the receiving unit to restore the data.

[0032] The data length of a packet conforming to space communication standards is greater than the data length of a data field in a frame conforming to CAN or CAN FD standards. As described above, by receiving a frame containing segmented data obtained by dividing the data contained in the packet, and combining the segmented data contained in each of the received frames to reconstruct the data, various processing can be performed using the reconstructed data. Therefore, data contained in a packet conforming to space communication standards can be processed in a network conforming to CAN or CAN FD standards.

[0033] Embodiments of this disclosure will be described below with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and their descriptions will not be repeated. Furthermore, at least some of the embodiments described below may be combined in any way.

[0034] [Space communication system] Figure 1 is a diagram showing an example of the configuration of a space communication system according to an embodiment of the present disclosure. Referring to Figure 1, the space communication system 501 comprises, for example, a plurality of spacecraft 301.

[0035] In the example shown in Figure 1, the space communication system 501 comprises multiple spacecraft 301, namely spacecraft 301A and 301B. Spacecraft 301A and 301B include artificial satellites, space probes, and space shuttles, etc.

[0036] Furthermore, the space communication system 501 is not limited to a configuration comprising two spacecraft 301, but may also comprise three or more spacecraft 301. Also, the space communication system 501 is not limited to a configuration comprising multiple spacecraft 301, but may also comprise one spacecraft 301.

[0037] [Spacecraft] Figure 2 is a diagram showing an example of the configuration of a spacecraft according to the embodiment of the present disclosure. Figure 2 shows the configuration of spacecraft 301A.

[0038] Referring to Figure 2, the spacecraft 301A is equipped with multiple space communication devices 101. In the example shown in Figure 2, the spacecraft 301 is equipped with multiple space communication devices 101, namely space communication devices 101A, 101B, and 101C.

[0039] Space communication devices 101B and 101C are connected to space communication device 101A, for example, via CAN bus 51. Space communication devices 101A, 101B, and 101C constitute the onboard subnetwork 401, which is a network within spacecraft 301A. CAN is an example of a second standard.

[0040] Furthermore, the number of space communication devices 101 connected to the CAN bus 51 is not limited to two; it may be three or more.

[0041] Information is transmitted and received between space communication devices 101 in accordance with the CAN standard. Specifically, space communication device 101 transmits a CAN frame containing various types of information to another space communication device 101.

[0042] For example, space communication device 101A transmits various data, such as observational data showing the results of observations of objects in outer space, to space communication devices 101B and 101C. Hereinafter, space communication device 101A will also be referred to as the data transmission device.

[0043] The space communication devices 101B and 101C perform predetermined processing using various data received from the space communication device 101A. Hereinafter, each of the space communication devices 101B and 101C will also be referred to as a data receiving device.

[0044] [Data transmission device] Figure 3 is a diagram showing an example of the configuration of a space communication device according to an embodiment of the present disclosure. Figure 3 shows the configuration of the space communication device 101A, i.e., the data transmission device.

[0045] Referring to Figure 3, the data transmission device comprises an observation unit 11, a space packet acquisition unit 12, a CAN-MA (CAN-Memory Access) packet creation unit 13, a CAN frame creation unit 14, a communication unit 15, and a storage unit 16. Some or all of the observation unit 11, the space packet acquisition unit 12, the CAN-MA packet creation unit 13, the CAN frame creation unit 14, and the communication unit 15 are implemented by, for example, one or more processing circuits. The storage unit 16 is a non-volatile memory included in the processing circuit. The communication unit 15 is an example of a transmission unit.

[0046] (Observation Department) For example, the observation unit 11 performs observation processing to observe objects in outer space. These objects include space debris and other spacecraft 301 that are different from the spacecraft 301 on which its own data transmission device is installed.

[0047] The observation unit 11 performs observation processing, for example, periodically or irregularly. Each time the observation unit 11 performs observation processing, it stores observation data indicating the observation results in the storage unit 16.

[0048] (Space packet) The space packet acquisition unit 12 acquires a space packet P1 that conforms to the space packet protocol used in space communications. The space packet protocol is an example of a first standard, and space packet P1 is an example of a first packet.

[0049] The Space Packet Protocol (SPP) is a communication protocol for space communications, standardized by the Space Data Systems Advisory Committee (CCSDS). The SPP is a network layer protocol in the OSI reference model.

[0050] The space packet acquisition unit 12 performs a creation process to acquire space packet P1, for example, by creating space packet P1.

[0051] Specifically, for example, the space packet acquisition unit 12 performs a creation process C1 to create a space packet P1 (hereinafter also referred to as "space packet P11") containing observation data for writing to the storage unit 24 in the data receiving device (hereinafter also referred to as "Write process").

[0052] Furthermore, for example, the space packet acquisition unit 12 performs a creation process C2 to create a space packet P1 (hereinafter also referred to as "space packet P12") containing observation data requested by the data receiving device.

[0053] Space packet P1 has a data field. The data length of the data field is, for example, in the range of 1 byte to 65536 bytes. For example, observation data is stored in the data field of space packet P1.

[0054] (a1) Creation of space packet P11 For example, when the processing timing T of the creation process C1 arrives, the space packet acquisition unit 12 retrieves multiple observation data stored in the storage unit 16 by the observation unit 11 during the period from the previous processing timing T to the current processing timing T.

[0055] Then, the space packet acquisition unit 12 creates a space packet P11 containing the multiple observation data that have been extracted.

[0056] The space packet acquisition unit 12 outputs the created space packet P11 to the CAN-MA packet creation unit 13, and also outputs data information B1 to the CAN-MA packet creation unit 13 indicating that the multiple observation data contained in the space packet P11 are data for write processing.

[0057] (a2) Creation of space packet P12 The data receiving device shown in Figure 2, for example, holds an address table Tb2 that indicates the addresses of the observed data stored in the storage unit 16 of the data transmitting device.

[0058] The data receiving device uses its stored address table Tb2 to confirm the address in the storage unit 16 of the observed data that it requests the data transmitting device to transmit. Alternatively, the data receiving device may be configured to confirm the address in the storage unit 16 by a method other than the address table Tb2.

[0059] The data receiving device transmits data request information to the space communication device 101A, including the confirmed address, indicating a request to read the observation data (hereinafter also referred to as "Read processing").

[0060] In the space communication device 101A, the communication unit 15 outputs data request information received from the space communication device 101B to the space packet acquisition unit 12.

[0061] The space packet acquisition unit 12 retrieves the observed data of the address indicated by the data request information received from the communication unit 15 from the storage unit 16.

[0062] Then, the space packet acquisition unit 12 creates a space packet P12 containing the extracted observation data.

[0063] The space packet acquisition unit 12 outputs the created space packet P12 to the CAN-MA packet creation unit 13, and also outputs data information B2 to the CAN-MA packet creation unit 13 indicating that the observed data contained in the space packet P12 is data corresponding to the Read process requested by the data receiving device.

[0064] The space packet acquisition unit 12 may be configured to perform a process of acquiring space packets P1 from another spacecraft 301 different from the spacecraft 301A on which its own data transmission device is installed, instead of the creation processes C1 and C2 that create space packets P1.

[0065] Furthermore, the data stored in the data field of space packet P1 is not limited to observation data; it may also be other types of data, such as data related to health monitoring and data related to anomaly detection.

[0066] (Creation of CAN-MA packets) For example, the CAN-MA packet creation unit 13 creates a CAN-MA packet that contains data and conforms to the CAN-MA protocol. The CAN-MA packet is an example of a second packet. The CAN-MA protocol is an example of a third standard.

[0067] The CAN-MA protocol is a protocol that lies below the network layer and above the physical layer in the OSI reference model.

[0068] As an example, the CAN-MA packet creation unit 13 creates a CAN-MA packet containing observation data.

[0069] Figure 4 shows an example of a CAN-MA packet transmitted by a space communication device according to an embodiment of the present disclosure.

[0070] Referring to Figure 4, for example, a CAN-MA packet has a header Ha, a data field Da, and a CRC (Cyclic Redundancy Check) code. Specifically, a CAN-MA packet has the header Ha, the data field Da, and the CRC code in this order from the beginning of the packet.

[0071] In a CAN-MA packet, the header Ha indicates the type of data stored in the data field Da. Specifically, for example, the MSB (Most Significant Bit) of header Ha is flag F1, and the second bit from the MSB is flag F2.

[0072] Flag F1 indicates whether the data stored in the data field Da is data that corresponds to a write operation or data that corresponds to a read operation. For example, if the data stored in the data field Da is data that corresponds to a write operation, the value of flag F1 is set to "1". On the other hand, if the data stored in the data field Da is data that corresponds to a read operation, the value of flag F1 is set to "zero".

[0073] Flag F2 indicates whether the data stored in the data field Da is data included in the request packet or data included in the response packet. A request packet is a CAN-MA packet containing information (hereinafter also referred to as the "command") indicating a request to perform a Write or Read operation. A response packet is a CAN-MA packet containing information (hereinafter also referred to as the "reply") indicating that a Write or Read operation has been performed. For example, if the CAN-MA packet is a request packet, the value of flag F2 is set to "1". On the other hand, if the CAN-MA packet is a response packet, the value of flag F2 is set to "zero".

[0074] In the following explanation, the space communication device 101 that sends commands will also be referred to as the controller node, and the space communication device 101 that sends replies will also be referred to as the responder node.

[0075] The data length of data field Da ranges from 7 bytes to 65542 bytes. In other words, the data length of data field Da is the same as the data length of space packet P1.

[0076] CRC codes are used in data receiving devices to detect errors in the header Ha and data field Da of CAN-MA packets.

[0077] When the CAN-MA packet creation unit 13 receives a space packet P1 from the space packet acquisition unit 12, it creates a CAN-MA packet.

[0078] Specifically, for example, when the CAN-MA packet creation unit 13 receives a space packet P11 and data information B1 from the space packet acquisition unit 12, it decides to create a CAN-MA packet related to the write process.

[0079] For example, the storage unit 16 stores a usage status table Tb1 that shows the data writing status in the storage unit 24 of the data receiving device, which will be described later.

[0080] When the CAN-MA packet creation unit 13 determines that it is creating a CAN-MA packet related to a write operation, it refers to the usage table Tb1 in the storage unit 16 to confirm addresses where no data has been written (hereinafter also referred to as "free addresses").

[0081] When the CAN-MA packet creation unit 13 confirms an available address, it stores information indicating a request to execute a write operation (hereinafter also referred to as "write request information") and the available address in the header Ha, and creates a CAN-MA packet by storing the space packet P11 received from the space packet acquisition unit 12 in the data field Da. The CAN-MA packet creation unit 13 then sets the values ​​of flags F1 and F2 in the header Ha of the CAN-MA packet to "1" and "1", respectively.

[0082] The memory unit 16 stores a predetermined generating polynomial used to calculate the CRC code. The CAN-MA packet creation unit 13 calculates the remainder by dividing the header Ha and data field Da of the created CAN-MA packet by the generating polynomial stored in the memory unit 16. The CAN-MA packet creation unit 13 then adds the calculated remainder as the CRC code to the created CAN-MA packet.

[0083] On the other hand, when the CAN-MA packet creation unit 13 receives the space packet P12 and data information B2 from the space packet acquisition unit 12, it decides to create a CAN-MA packet related to the Read operation.

[0084] When the CAN-MA packet creation unit 13 determines that it is creating a CAN-MA packet related to a Read operation, it creates a CAN-MA packet in which it stores information indicating that the observation data requested by the data receiving device has been read from the storage unit 16 (hereinafter also referred to as "read completion information") in the header Ha, and stores the space packet P12 received from the space packet acquisition unit 12 in the data field Da. The CAN-MA packet creation unit 13 then sets the values ​​of flags F1 and F2 in the header Ha of the CAN-MA packet to "zero" and "zero," respectively.

[0085] The CAN-MA packet creation unit 13 outputs a CAN-MA packet with a CRC code added to it to the CAN frame creation unit 14.

[0086] (Creating a CAN frame) Figure 5 is a diagram illustrating the frame creation process by a space communication device according to an embodiment of the present disclosure.

[0087] Referring to Figures 3 and 5, the CAN frame creation unit 14 performs frame creation processing to create a CAN frame that includes segmented data obtained by dividing the observed data contained in the space packet P1 acquired by the space packet acquisition unit 12, and that conforms to the CAN standard.

[0088] More specifically, for example, the CAN frame creation unit 14 stores the CAN-MA packets created by the CAN-MA packet creation unit 13 in a CAN frame.

[0089] Specifically, the CAN frame creation unit 14 divides the CAN-MA packet received from the CAN-MA packet creation unit 13 into multiple segmented packets. That is, the CAN frame creation unit 14 divides the space packet P1 stored in the data field Da of the CAN-MA packet.

[0090] Each segmented packet contains segmented data, which is obtained by dividing the space packet P1 stored in the data field Da, i.e., the observed data contained in space packet P1 is divided into segments.

[0091] Each segmented packet has a header Hb and a data field Db in which the segmented data is stored. For example, the length of the header Hb and the length of the data field Db are 2 bytes and 6 bytes, respectively.

[0092] The top two bits of the header Hb indicate the position of the segmented data stored in the data field Db within the segmented packet.

[0093] Figure 6 shows an example of a CAN frame transmitted by a space communication device according to an embodiment of the present disclosure. Referring to Figure 6, a CAN frame has, from the beginning of the frame, an SOF (Start Of Frame) field, an extension field, a CONTROL field, a data field (hereinafter also referred to as a DAT field), a CRC field, an ACK (Acknowledgement) field, and an EOF (End Of Frame) field.

[0094] Referring to Figures 3, 5, and 6, the CAN frame creation unit 14 divides the CAN-MA packet received from the CAN-MA packet creation unit 13 into multiple divided packets, and then creates a CAN frame containing each divided packet. The divided packets are stored, for example, in the DAT field of the CAN frame.

[0095] Figure 7 shows an example of the format of the DAT field in a CAN frame transmitted by a data transmission device according to an embodiment of the present disclosure.

[0096] In Figure 7, the vertical direction represents bytes and the horizontal direction represents bits. The data length of the DAT field shown in Figure 7 is 8 bytes. The upper two bits of the "zero" byte in the DAT field indicate the "Data Field Sequence". The "Data Field Sequence" indicates whether the CAN frame containing the DAT field is the first CAN frame, the last CAN frame, or another CAN frame other than the first and last CAN frames (hereinafter also referred to as an "intermediate frame") transmitted from the data transmission device.

[0097] In this example, the "Data Field Sequence" values ​​in the first CAN frame, the last CAN frame, and the intermediate frame are "1," "2," and "zero," respectively.

[0098] Furthermore, the lower 6 bits and the 1st byte of the "zero" byte in the DAT field shown in Figure 7 represent the "Data Field Count." The "Data Field Count" is a value that indicates which CAN frame the DAT field is in, based on the data transmission device. In the example shown in Figure 7, the "Data Field Count" is represented by 14 bits.

[0099] Furthermore, the segmented packets are stored in bytes "2" through "7" of the DAT field shown in Figure 7.

[0100] The CAN frame creation unit 14 sequentially outputs the multiple CAN frames it has created to the communication unit 15.

[0101] (Transmitting CAN frames) The communication unit 15 transmits multiple CAN frames created by the CAN frame creation unit 14 to the data receiving device.

[0102] More specifically, the communication unit 15 sequentially transmits multiple CAN frames received from the CAN frame creation unit 14 to the data receiving device.

[0103] [Data receiving device] Figure 8 shows another example of the configuration of a space communication device according to an embodiment of the present disclosure. Figure 8 shows the configuration of space communication device 101B or space communication device 101C, i.e., a data receiving device.

[0104] Referring to Figure 8, the data receiving device comprises a communication unit 21, a restoration unit 22, a packet processing unit 23, and a storage unit 24. Some or all of the communication unit 21, the restoration unit 22, and the packet processing unit 23 are implemented, for example, by one or more processing circuits. The storage unit 24 is a non-volatile memory included in the processing circuit. The communication unit 21 is an example of a receiving unit.

[0105] The communication unit 21 receives CAN frames from the space communication device 101A. More specifically, the communication unit 21 sequentially receives multiple CAN frames from the space communication device 101A.

[0106] The communication unit 21 outputs the CAN frame to the reconstruction unit 22 each time it receives a CAN frame from the space communication device 101A.

[0107] (Restoration Department) The restoration unit 22 combines the multiple segmented data contained in each of the multiple CAN frames received by the communication unit 21 and performs restoration processing to restore the data contained in the space packet P1 acquired by the data transmission device.

[0108] More specifically, the restoration unit 22 restores the CAN-MA packet containing the space packet P1 by combining the multiple segmented packets contained in each of the multiple CAN frames received by the communication unit 21.

[0109] Specifically, when the recovery unit 22 receives a CAN frame from the communication unit 21, it checks the value of "Data Field Sequence" in that CAN frame. For example, if the recovery unit 22 finds that the value of "Data Field Sequence" in the CAN frame received from the communication unit 21 is "1" or "zero", it determines that the CAN frame is not the last CAN frame transmitted from the data transmission device. The recovery unit 22 then stores the CAN frame in the storage unit 24.

[0110] The restoration unit 22 determines that a CAN frame received from the communication unit 21 is the last CAN frame if the "Data Field Sequence" value in that CAN frame is "2". The restoration unit 22 then uses that CAN frame and multiple CAN frames stored in the storage unit 24, where the "Data Field Sequence" value is "1" or "zero", to restore the CAN-MA packet.

[0111] The restoration unit 22 then performs error detection on the header Ha and data field Da in the restored CAN-MA packet. For example, the storage unit 24 stores the same generator polynomial as the one held by the data transmission device.

[0112] The restoration unit 22 calculates the remainder by dividing the header Ha and data field Da of the restored CAN-MA packet by the generating polynomial stored in the storage unit 24. The restoration unit 22 compares the calculated remainder with the CRC code in the restored CAN-MA packet.

[0113] If the calculated remainder and the CRC code in the restored CAN-MA packet are the same, the restoration unit 22 outputs the CAN-MA packet to the packet processing unit 23.

[0114] On the other hand, if the calculated remainder differs from the CRC code in the restored CAN-MA packet, the restoration unit 22 discards the CAN-MA packet.

[0115] (Packet processing unit 23) The packet processing unit 23 performs predetermined processing using the CAN-MA packets restored by the restoration unit 22.

[0116] More specifically, when the packet processing unit 23 receives a CAN-MA packet from the restoration unit 22, it checks the flags F1 and F2 of the header Ha in the CAN-MA packet.

[0117] Then, the packet processing unit 23 performs a write operation if flags F1 and F2 are "1" and "1", respectively. More specifically, the packet processing unit 23 writes the space packet P11 containing the observed data, which is stored in the data field Da of the CAN-MA packet received from the restoration unit 22, to the storage unit 24.

[0118] Specifically, the packet processing unit 23 writes the space packet P11 stored in the data field Da to an empty address stored in the header Ha. The packet processing unit 23 may also be configured to write the observed data to an arbitrary address in the storage unit 24. In other words, the header Ha does not necessarily have to contain an empty address.

[0119] When the packet processing unit 23 completes the write operation, it sends write completion information to the data transmission device indicating that the write operation has been completed.

[0120] When the data transmission device shown in Figure 3 receives write completion information from the data receiving device, it updates the usage status table Tb1 in the storage unit 16. Specifically, for example, the data transmission device changes the write status in the usage status table Tb1 to "written" at the address corresponding to the write completion information received from the data receiving device.

[0121] On the other hand, in the data receiving device, if flags F1 and F2 are "zero" and "zero," respectively, the packet processing unit 23 performs predetermined processing using the space packet P12 containing the observed data stored in the data field Da of the CAN-MA packet received from the restoration unit 22. For example, the packet processing unit 23 uses the space packet P12 to generate a control signal for controlling equipment (not shown) connected to its own data receiving device.

[0122] [Operation Flow] Next, the operation flow of each device in the space communication system 501 according to the embodiment of this disclosure will be explained with reference to the drawings.

[0123] Figure 9 is a flowchart illustrating an example of the operation procedure when a data transmission device according to an embodiment of the present disclosure performs the process of transmitting a CAN frame. Figure 9 shows the case in which the data transmission device transmits a CAN frame containing segmented data obtained by dividing the observed data contained in a space packet P11.

[0124] Referring to Figure 9, first, the data transmission device waits for the processing timing T of the creation process C1, which creates the space packet P11, to arrive (NO in step ST101).

[0125] Then, when the processing timing T arrives (YES in step ST101), the data transmission device retrieves multiple observation data stored in the storage unit 16 during the period from the previous processing timing T to the current processing timing T (step ST102).

[0126] Next, the data transmission device creates a space packet P11 containing the extracted observation data (step ST103).

[0127] Next, the data transmission device creates a CAN-MA packet having a header Ha containing write request information and an available address, a data field Da containing the created space packet P11, and a CRC code (step ST104).

[0128] Next, the data transmission device divides the created CAN-MA packet into multiple segmented packets (step ST105).

[0129] Next, the data transmission device creates multiple CAN frames, each containing multiple segmented packets (step ST106).

[0130] Next, the data transmission device sequentially transmits the multiple CAN frames it has created to the data receiving device (step ST107) and waits for the next processing timing T to arrive (NO in step ST101).

[0131] Figure 10 is a flowchart illustrating an example of the operation procedure when a data transmission device according to an embodiment of the present disclosure performs the process of transmitting a CAN frame. Figure 10 shows a case in which the data transmission device transmits a CAN frame that includes segmented data obtained by dividing the observed data contained in a space packet P12.

[0132] Referring to Figure 10, first, the data transmission device waits for the reception of data request information from the data receiving device (NO in step ST201).

[0133] Then, when the data transmission device receives data request information from the data receiving device (YES in step ST201), it retrieves the observed data for the address indicated by the data request information from the storage unit 16 (step ST202).

[0134] Next, the data transmission device creates a space packet P12 containing the extracted observation data (step ST203).

[0135] Next, the data transmission device creates a CAN-MA packet having a header Ha containing read completion information, a data field Da containing the created space packet P12, and a CRC code (step ST204).

[0136] Steps ST205 and ST206 are the same as steps ST105 and ST106 shown in Figure 9, respectively.

[0137] Next, the data transmission device sequentially transmits the multiple CAN frames it has created to the data receiving device (step ST207) and waits for new data request information to be received from the data receiving device (NO in step ST201).

[0138] Figures 11 and 12 are flowcharts illustrating an example of the operation procedure when a data receiving device according to an embodiment of the present disclosure performs a restoration process.

[0139] Referring to Figures 11 and 12, first the data receiving device waits for the reception of a CAN frame from the data transmitting device (NO in step ST301).

[0140] The data receiving device then receives a CAN frame from the data transmitting device, and if the value of "Data Field Sequence" in the CAN frame is "1" or "zero" (YES in step ST301 and YES in step ST302), it stores the CAN frame in the storage unit 24 (step ST303) and waits for the reception of a new CAN frame from the data transmitting device (NO in step ST301).

[0141] On the other hand, if the value of "Data Field Sequence" in the received CAN frame is "2" (YES in step ST301 and NO in step ST302), the data receiving device performs a restoration process to restore the CAN-MA packet using the segmented packets contained in the received CAN frame and the segmented packets contained in other CAN frames stored in the storage unit 24 (step ST304).

[0142] Next, the data receiving device performs error detection on the restored CAN-MA packets (step ST305).

[0143] Next, if no errors are detected in the restored CAN-MA packet (NO in step ST305), the data receiving device performs predetermined processing using the CAN-MA packet (step ST306).

[0144] On the other hand, if the data receiving device detects an error in the restored CAN-MA packet (YES in step ST305), it discards the CAN-MA packet (step ST307).

[0145] Figure 13 shows an example of the processing sequence of a data transmission device and a data reception device in a space communication system according to an embodiment of the present disclosure. Figure 13 shows a case where the segmented packets included in the CAN frame transmitted by the data transmission device to the data reception device are segmented packets obtained by dividing a CAN-MA packet in which a space packet P11 is stored in the data field Da.

[0146] Referring to Figure 13, first the data transmission device creates a space packet P11 containing the observation data (step ST401).

[0147] Next, the data transmission device creates a CAN-MA packet containing a header Ha storing the write request information and an available address in the storage unit 24 of the data reception device, a data field Da storing the created space packet P11, and a CRC code (step ST402).

[0148] Next, the data transmission device divides the created CAN-MA packet into multiple segmented packets (step ST403).

[0149] Next, the data transmission device creates multiple CAN frames, each containing multiple segmented packets (step ST404).

[0150] Next, the data transmission device sequentially transmits the multiple CAN frames it has created to the data receiving device (step ST405).

[0151] Next, when the data receiving device receives all of the multiple CAN frames, each containing multiple segmented packets, from the data transmitting device, it uses these multiple segmented packets to reconstruct the CAN-MA packet (step ST406).

[0152] Next, the data receiving device performs error detection on the restored CAN-MA packet. Here, we assume that the data receiving device did not detect any errors in the CAN-MA packet (step ST407).

[0153] Next, the data receiving device performs predetermined processing using the restored CAN-MA packet. Here, the data receiving device performs a write operation, that is, writes the space packet P11 stored in the data field Da of the restored CAN-MA packet to the storage unit 24, according to the write request information contained in the CAN-MA packet (step ST408).

[0154] In the space communication system 501 according to the embodiment of this disclosure, the data transmission device is configured to store divided packets obtained by dividing a CAN-MA packet, i.e., packets obtained by dividing a space packet P1, in a CAN frame and transmit them to the data receiving device. However, the system is not limited to this configuration. The data transmission device may also be configured to store the divided data in a frame conforming to the CAN FD standard and transmit it to the data receiving device.

[0155] Furthermore, in the space communication system 501 according to the embodiment of this disclosure, the data transmission device stores space packet P1 in the data field Da of a packet that follows a protocol of a layer lower than the network layer in the OSI reference model and a protocol of a layer higher than the physical layer, and the packet has a header Ha and a CRC code, but is not limited to this. The packet in which space packet P1 is stored does not have to have at least one of the header Ha and the CRC code.

[0156] Furthermore, in the space communication system 501 according to the embodiment of this disclosure, the data transmission device is configured to divide a CAN-MA packet containing write request information or read completion information, i.e., a CAN-MA packet containing information indicating whether the data contained in the data field Da is data corresponding to a write operation or data corresponding to a read operation, and store it in a CAN frame, but is not limited to this. The type of data transmitted to the data receiving device may be data for purposes other than write and read operations.

[0157] Furthermore, while the space communication system 501 according to the embodiments of this disclosure is configured such that the data transmission device and the data reception device are each installed in an onboard subnetwork 401 of a spacecraft 301, the disclosure is not limited to this configuration. The spacecraft 301 on which the data transmission device is installed and the spacecraft 301 on which the data reception device is installed may have different configurations. Also, the data transmission device and the data reception device may each be installed in a ground station that communicates with the spacecraft 301. In addition, when a vehicle communicates with the spacecraft 301, the data transmission device and the data reception device may each be installed in the vehicle. Furthermore, the data transmission device and the data reception device may each be installed in a subsystem of a spacecraft 301.

[0158] [Example 1] Commands and replies transmitted and received between space communication devices 101 in the onboard subnetwork 401 may be assigned a priority.

[0159] Figure 14 is a diagram illustrating the priority set for commands and replies transmitted and received by Modification 1 of the space communication device according to the embodiment of this disclosure.

[0160] Referring to Figure 14, in the space communication system 501, for each command and reply, two types of priority, such as high and low, are set.

[0161] The space communication device 101 modifies the CAN-ID (Identifier) ​​included in the CAN frame according to the command priority and reply priority.

[0162] In the example shown in Figure 14, the CAN-ID in a CAN frame sent by a controller node, containing a "high-priority command" and "various data," is "0x300" with the ID of the responder node to which the CAN frame is sent appended. The CAN-ID in a CAN frame sent by a responder node, containing a "high-priority reply" and "various data," is "0x400" with the ID of the responder node appended. The CAN-ID in a CAN frame sent by a controller node, containing a "low-priority command" and "various data," is "0x500" with the ID of the responder node to which the CAN frame is sent appended. The CAN-ID in a CAN frame sent by a responder node, containing a "low-priority reply" and "various data," is "0x600" with the ID of the responder node appended. Here, a number starting with "0x" means that the numbers after "0x" are represented in hexadecimal.

[0163] Incidentally, in the space communication system 501, the time constraints on data may differ depending on the type of data. For example, for data transmitted and received in the onboard subnetwork 401, such as data related to health monitoring and anomaly detection, the required time from when the controller node sends a command until it receives a reply may be set shorter compared to other data, such as data transmitted and received between spacecraft 301s and data transmitted and received between spacecraft 301s and ground stations. As described above, by setting priorities for each command and reply, the space communication system 501 can handle both the transmission and reception of data with strict time constraints and data with loose time constraints.

[0164] [Differentiation 2] The data transmission device may be configured to send a CAN frame with the following structure to the data receiving device.

[0165] Figure 15 shows an example of the format of the DAT field in a CAN frame transmitted by Modification 2 of the data transmission device according to the embodiment of this disclosure.

[0166] In Figure 15, the vertical direction represents bytes and the horizontal direction represents bits. The format of the DAT field in the CAN frame shown in Figure 15 differs from the format shown in Figure 7 in that the lower 6 bits of the "zero" byte in the DAT field represent the "Data Field Count," and the segmented packets are stored in bytes "1" through "7" of the DAT field. This allows for an increase in the data size of segmented packets that can be stored in the DAT field.

[0167] [Difference 3] Furthermore, the data transmission device may be configured to transmit a CAN frame with the following structure to the data receiving device.

[0168] Figures 16, 17, and 18 show an example of the format of the DAT field in a CAN frame transmitted by Modification 3 of the data transmission device according to the embodiment of this disclosure. In Figures 16, 17, and 18, the vertical direction represents bytes and the horizontal direction represents bits.

[0169] The DAT field format shown in Figure 16 represents the format of the DAT field in the first CAN frame transmitted by the data transmitter to the data receiver. The DAT field format shown in Figure 17 represents the format of the DAT field in an intermediate frame transmitted by the data transmitter to the data receiver. The DAT field format shown in Figure 18 represents the format of the DAT field in the final CAN frame transmitted by the data transmitter to the data receiver.

[0170] Referring to Figure 16, in the DAT field of the first CAN frame, the zeroth and first bytes represent the flag sequence S1, which indicates that it contains the first segmented packet. In the example shown in Figure 16, the flag sequence S1 is "0x0001".

[0171] In the DAT field of the first CAN frame, the segmented packets are stored in bytes 2 through 7.

[0172] Referring to Figure 17, in the DAT field of the intermediate frame, the segmented packets are stored in bytes 0 through 7.

[0173] Referring to Figure 18, in the DAT field of the last CAN frame, the segmented packets are stored in bytes 0 through 5.

[0174] In the DAT field of the last CAN frame, bytes 6 and 7 indicate the flag sequence S2, which indicates that it contains the last segmented packet. In the example shown in Figure 18, the flag sequence S2 is "0x0002".

[0175] Thus, in this configuration, where each of the multiple CAN frames transmitted from the data transmitter to the data receiver has flag sequences S1 and S2, it becomes unnecessary to include information indicating which CAN frame it is in the intermediate frames. Furthermore, it is possible to include split packets with a data length equal to the maximum data length of the DAT field. Therefore, when the data length of CAN-MA packets is large, the number of CAN frames transmitted and received between the data transmitter and data receiver can be reduced.

[0176] [Differentiation Example 4] Furthermore, the data transmission device may be configured to create a CAN frame containing other data in addition to the data included in the space packet P1, and transmit it to the data receiving device.

[0177] Referring again to Figures 2 and 3, for example, the data transmission device may be configured to transmit to the data receiving device a CAN frame containing data different from the data contained in the space packet P1. This other data is, for example, data obtained from another device other than the data receiving device when that device is connected to the data transmission device via the CAN bus 51.

[0178] Furthermore, for example, a data transmission device may be configured to acquire not only space packet P1 but also packet P2 that conforms to other space communication standards other than the Space Packet Protocol. Such other standards include CFDP (CCSDS File Delivery Protocol), etc.

[0179] In this case, for example, the data transmission device creates a CAN frame that includes the divided data obtained by dividing the data contained in space packet P1, as well as the divided data obtained by dividing the data contained in packet P2, and sends it to the data receiving device.

[0180] The embodiments described above should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims rather than the above description, and all modifications within the meaning and scope equivalent to the claims are intended to be included.

[0181] Each process (each function) of the above-described embodiment is implemented by a processing circuit including one or more processors. The processing circuit may consist of one or more memories, various analog circuits, various digital circuits, and other integrated circuits in addition to the one or more processors. The one or more memories store programs (instructions) that cause the one or more processors to execute each of the above processes. The one or more processors may execute each of the above processes according to the programs read from the one or more memories, or they may execute each of the above processes according to logic circuits that have been pre-designed to execute each of the above processes. The processors may be various processors suitable for computer control, such as a CPU (Central Processing Unit), GPU (Graphics Processing Unit), DSP (Digital Signal Processor), FPGA (Field Programmable Gate Array), and ASIC (Application Specific Integrated Circuit). Furthermore, the physically separated multiple processors may cooperate with each other to execute each of the above processes. For example, the processors installed in each of several physically separate computers may cooperate with each other via a network such as a LAN (Local Area Network), WAN (Wide Area Network), and the Internet to perform the above processes. The program may be installed in the memory via the network from an external server device, or it may be distributed on a recording medium such as a CD-ROM (Compact Disc Read Only Memory), DVD-ROM (Digital Versatile Disk Read Only Memory), and semiconductor memory, and then installed in the memory from the recording medium.

[0182] The above description includes the following features. [Note 1] A space communication method in a space communication device, Steps include obtaining packets that conform to the first standard used in space communications, The steps include creating a frame that includes segmented data from the acquired packet and conforms to a second standard which is a CAN or CAN FD standard, A space communication method comprising the step of transmitting the created frame to another device.

[0183] [Note 2] A space communication method in a space communication device used in a space communication system, The steps include receiving a frame from another space communication device that conforms to the CAN or CAN FD standard, and which stores segmented data obtained by dividing the data contained in a packet used in space communication, A space communication method comprising the step of combining a plurality of divided data contained in each of the received plurality of frames to restore the data.

[0184] [Note 3] Equipped with a processing circuit, The aforementioned processing circuit is We obtain packets that conform to the first standard used in space communications. The data contained in the acquired packet includes segmented data, and a frame is created that conforms to the second standard, which is a CAN or CAN FD standard. A space communication device that transmits the created frame to other devices.

[0185] [Note 4] A space communication device used in a space communication system, Equipped with a processing circuit, The aforementioned processing circuit is A frame conforming to the CAN or CAN FD standard, in which data contained in a packet used in space communications is divided into segmented data, is received from another space communications device. A space communication device that reconstructs data by combining multiple divided data contained in each of the received frames. [Explanation of Symbols]

[0186] 11 Observation Department 12 Space Packet Acquisition Unit 13 CAN-MA packet creation section 14. CAN Frame Creation Section 15,21 Communications Department 16,24 Storage section 22 Restoration Section 23 Packet Processing Unit 51 CAN bus 101,101A,101B Space communication equipment 301,301A,301B Spacecraft 501 Space Communication System

Claims

1. First space communication device, Equipped with a second space communication device, The first space communication device acquires a first packet in accordance with a first standard used in space communications, The first space communication device stores the divided data, which is the data contained in the acquired first packet, into a frame conforming to the second standard, which is a CAN or CAN FD standard, and transmits it to the second space communication device. The second space communication device is a space communication system that reconstructs data by combining a plurality of divided data contained in a plurality of frames received from the first space communication device.

2. The first space communication device creates a second packet which includes a header indicating the type of data, the data, and a CRC code, and which conforms to a third standard that is different from the first and second standards. The space communication system according to claim 1, wherein the first space communication device divides the created second packet and stores it in the frame.

3. The first space communication device creates a second packet that includes the data and conforms to a third standard that is different from the first and second standards. The second packet further includes information indicating a request to write the data to the memory of the second space communication device, or information indicating that the data requested by the second space communication device has been read from the memory of the first space communication device. The space communication system according to claim 1 or 2, wherein the first space communication device divides the created second packet and stores it in the frame.

4. The space communication system according to claim 1 or 2, wherein the first space communication device transmits to the second space communication device a frame containing data which is divided data, in addition to the divided data, other data different from the data contained in the first packet.

5. The first space communication device further acquires a third packet that conforms to a fourth standard used in space communications, which is different from the first standard. The space communication system according to claim 2, wherein the first space communication device creates a second packet that further includes the data contained in the third packet in addition to the data contained in the first packet.

6. An acquisition unit that acquires packets conforming to the first standard used in space communications, A creation unit creates a frame that includes segmented data obtained from the packet acquired by the acquisition unit, and that conforms to a second standard which is a CAN or CAN FD standard. A space communication device comprising a transmission unit that transmits the frame created by the creation unit to another device.

7. A space communication device used in a space communication system, A receiving unit that receives a frame from another space communication device, which is a frame conforming to the CAN or CAN FD standard, and which stores segmented data obtained by dividing the data contained in a packet used in space communication. A space communication device comprising: a restoration unit that combines a plurality of divided data contained in each of the plurality of frames received by the receiving unit to restore the data.

8. A space communication method in a space communication system comprising a first space communication device and a second space communication device, The first space communication device acquires a first packet in accordance with a first standard used in space communication, The first space communication device stores the divided data obtained from the first packet into a frame conforming to a second standard which is a CAN or CAN FD standard, and transmits it to the second space communication device. A space communication method comprising the step of the second space communication device combining a plurality of divided data contained in each of the plurality of frames received from the first space communication device to restore the data.

9. A space communication program used in space communication equipment, Computers, An acquisition unit that acquires packets conforming to the first standard used in space communications, A transmitting unit that stores the divided data, obtained by dividing the data contained in the packet acquired by the acquisition unit, into a frame conforming to the second standard, which is a CAN or CAN FD standard, and transmits it to another device. A space communications program designed to function as such.

10. A space communication device used in a space communication system, and a space communication program used in such a device. Computers, A receiving unit that receives a frame from another space communication device, which is a frame conforming to the CAN or CAN FD standard, and which stores segmented data obtained by dividing the data contained in a packet used in space communication. A restoration unit that combines the multiple divided data contained in each of the multiple frames received by the receiving unit to restore the data, A space communications program designed to function as such.

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