Spacecraft

Abstract

A spacecraft is provided that adopts a more efficient amplifier configuration. A spacecraft is provided, the spacecraft comprising: a main body having a storage space for storing electronic equipment inside; an oscillator configured to output radio waves with a frequency including a predetermined frequency band; an amplifier configured to be exposed to outer space by being arranged in an external package of the main body and configured to amplify the power of the radio waves output by the oscillator; and an antenna configured to be arranged in an external package of the main body and used to transmit the radio waves to the outside with the power amplified by the amplifier.

Description

Technical Field

[0001] The present disclosure relates to a spacecraft capable of emitting radio waves to the outside, wherein the radio waves include frequencies in a predetermined frequency band. Background Art

[0002] Conventionally, in spacecraft such as artificial satellites, radio waves are emitted to the outside for communication with ground stations or data observation. Patent Document 1 describes a satellite including a satellite-borne microwave transmitting device, which includes an antenna horn for inputting a generated microwave signal and an antenna for transmitting the microwave signal to the ground. In such a satellite, in order to achieve high output power, a high-output power amplifier for amplifying the generated microwave signal before inputting it to the antenna horn has been used.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2012-207981 Summary of the invention

[0006] Problems to be solved by the invention

[0007] Therefore, in view of the above-described technology, the present disclosure provides, through various embodiments, a spacecraft that employs a more efficient amplifier configuration.

[0008] Means for solving problems

[0009] According to one embodiment of the present disclosure, there is provided a spacecraft, comprising: a main body having a storage space for storing electronic equipment inside; an oscillator configured to output radio waves with a frequency including a specified frequency band; an amplifier, which is arranged in an external package of the main body so as to be exposed to outer space and is configured to amplify the power of the radio waves output by the oscillator; and an antenna, which is arranged in the external package of the main body and is used to transmit the radio waves to the outside with the power amplified by the amplifier.

[0010] Effects of the Invention

[0011] Various embodiments of the present disclosure can provide a spacecraft that employs a more efficient amplifier configuration.

[0012] In addition, the above effects are merely examples for convenience of explanation and are not limiting. In addition to the above effects, or in place of the above effects, any effects described in the present disclosure or effects obvious to those skilled in the art may also be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1This is a diagram showing a schematic configuration of a spacecraft 1 according to a first embodiment of the present disclosure.

[0014] Figure 2 It is a block diagram showing the structure of the spacecraft 1 according to the first embodiment of the present disclosure.

[0015] Figure 3 It is a block diagram showing the structure of the transmitter 110 according to the first embodiment of the present disclosure.

[0016] Figure 4 It is a side view showing the outline of the structure of the spacecraft 1 according to the first embodiment of the present disclosure.

[0017] Figure 5 It is a plan view showing the outline of the structure of the spacecraft 1 according to the first embodiment of the present disclosure.

[0018] Figure 6 It is a side view showing the schematic structure of the amplifier 112 according to the first embodiment of the present disclosure.

[0019] Figure 7 It is a plan view showing the schematic structure of the amplifier 112 according to the first embodiment of the present disclosure. DETAILED DESCRIPTION

[0020] Various embodiments of the present disclosure will be described with reference to the accompanying drawings. In addition, the same reference numerals are given to common components in the drawings.

[0021] <First Embodiment>

[0022] 1. Structure of Spacecraft 1

[0023] Figure 1 1 is a diagram showing a schematic configuration of a spacecraft 1 according to a first embodiment of the present disclosure. Figure 1 The spacecraft 1 includes: a main body 300, which is equipped with a control unit and other equipment, and the control unit controls the navigation of the spacecraft 1 itself, the movement and posture of the spacecraft 1 in the outer space; a power supply unit 200, which provides power for driving various components including the control unit and the communication unit 100 in the outer space; and a communication unit 100, which is used to transmit radio waves toward the spacecraft 1 and the external outer space where there are ground or other spacecraft, and receive radio waves from the outer space.

[0024] In the present embodiment, as an example, the spacecraft 1 can be used as a small SAR satellite for carrying SAR (synthetic aperture radar). Such a small SAR satellite can be used to observe and analyze the observation object by emitting microwave, millimeter wave or submillimeter wave band radio waves to the observation object and receiving the reflected waves from the observation object. Here, in the SAR radar that receives the reflected waves from the observation object, high output power is required, so an amplifier equipped with power is required. The amplifier generates high output power and may become a very large heat source. Therefore, especially in the case of using the spacecraft 1 as a small SAR satellite, how to efficiently dissipate the heat from the amplifier is very important. On the other hand, in a small SAR satellite, electronic components including the amplifier need to be arranged in a limited storage space, so it is more important to efficiently arrange the electronic components on the basis of considering the heat dissipation effect.

[0025] In addition, the following Figure 1 The case where the spacecraft 1 is used as a small SAR satellite will be described. However, the present embodiment is not limited to the case where it is used as a small SAR satellite, and can also be used for other purposes, other forms (large satellites), etc.

[0026] The main body 300 has a storage space (not shown) for storing various electronic devices and mechanism components inside. As an example, the main body 300 is formed by an octahedron having a hexagonal shape when viewed from above, and is formed into a hollow shape to form a storage space inside the main body 300. However, the shape of the main body 300 can be any shape such as other polyhedrons and spheres as long as a storage space can be formed inside it. In addition, the following describes the case where the main body 300 is formed into an octahedron having a hexagonal shape when viewed from above.

[0027] The storage space formed inside the main body 300 stores various electronic components such as the computer 301, the sensor 330, the actuator 340, the power supply control circuit 201, the battery 220, and the communication control circuit 170, and wiring for electrically connecting them.

[0028] In this embodiment, the power supply unit 200 includes a solar panel 230. As an example, the solar panel 230 is arranged on the wall surface of the main body 300 so as to cover the outer surface of the main body 300. By arranging in this way, the wall surface of the main body 300 can be effectively used.

[0029] In addition to the transmitter 110, the communication unit 100 also includes: a radiator 120; a sub-reflector (sub-reflector) 131, which is configured to be opposite to the radiator 120 at a specified angle, and the sub-reflector 131 is used to reflect the radio waves emitted from the radiator 120 to the main reflector 132; the main reflector 132 as the main reflector, which is configured to be opposite to the mirror surface of the sub-reflector 131, further reflects the radio waves reflected by the sub-reflector 131 and emits the radio waves to the outside; and a support rod 135, which is used to support the sub-reflector 131.

[0030] The main reflector 132 includes a hub 139, a plurality of ribs 136, a planar body 137, etc. The reflecting surface of the main reflector 132 is formed in a parabolic shape so as to function as a main reflector as described above.

[0031] The hub 139 is provided on the antenna axis X (also referred to as the central axis X of the hub 139) at the center of the main reflector 132 and on the side of the main body 300 where the sub-reflector 131 is arranged. As an example, the hub 139 is formed into a substantially cylindrical shape using a dielectric such as plastic or a metal such as titanium or stainless steel. The hub 139 is provided with a plurality of ribs 136 radially arranged at predetermined intervals on its outer peripheral surface with the central axis X as the center. That is, the cross-sectional shape of the hub 139 (the cross-sectional shape when viewed from the direction along the central axis X) is a circular shape, but the shape may be formed in any shape of an elliptical shape or a polygonal shape.

[0032] The rib 136 includes a plurality of ribs. The ribs 136 are radially arranged on the outer periphery of the hub 139 at predetermined intervals with the hub 139 as the center. The upper surface of each rib 136, which is a reflective mirror surface, is formed in a parabolic shape. Moreover, a planar body 137 is provided on the upper surface formed in the parabolic shape. As an example, the rib 136 is a spring member formed of a composite material such as stainless spring steel, GFRP (Glass Fiber Reinforced Plastics), CFRP (Carbon Fiber Reinforced Plastics), and has elasticity.

[0033] In addition, in the present embodiment, the ribs 136 are composed of a total of 24 ribs. However, the number of ribs 136 can be changed according to the area of ​​the unfolded antenna, the material and strength of the ribs used, etc., and it is not related to an even number or an odd number. In addition, in the present embodiment, the ribs 136 are arranged at a predetermined interval, but the interval can be a constant interval in all the ribs 136, or the interval can be made dense only in a part, or it can be irregular.

[0034] The planar body 137 constituting the main reflector 132 together with the ribs 136 is arranged between a pair of ribs 136 adjacent to each other. The planar body 137 is formed into a parabolic shape as a whole using a material capable of reflecting radio waves. As an example, the planar body 137 is formed by a metal mesh (metal mesh), and the metal is formed by molybdenum, gold or a combination thereof. In the present embodiment, the planar body 137 is a metal mesh having a substantially triangular shape prepared according to the number of the ribs 136, and each metal mesh is sewn and arranged on the upper surface of the ribs 136 formed into a parabolic shape.

[0035] The sub-reflector 131 is disposed opposite to the main reflector 132, and the lower surface side (the side corresponding to the main reflector 132) of the sub-reflector 131 is supported by a support rod 135. The sub-reflector 131 is disposed at a predetermined distance from the radiator 120 disposed on the line of the central axis X thereof by the support rod 135. The sub-reflector 131 is made of a material capable of reflecting radio waves, similarly to the planar body 137 of the main reflector 132, and has a quadratic surface shape whose surface faces the main reflector 132 as a whole. Moreover, the sub-reflector 131 reflects the radio waves radiated from the radiator 120 toward the main reflector 132. Therefore, the sub-reflector 131 is disposed at a predetermined distance from the radiator 120 and the main reflector 132.

[0036] The support rod 135 is configured to separate the sub-reflector 131 from the radiator 120 and the main reflector 132 by a predetermined distance. The support rod 135 includes: a first support rod 133, one end of which is connected to the sub-reflector 131, and the other end is connected to the joint 138; and a second support rod 134, one end of which is connected to the joint 138, and the other end is connected to the main body. The sub-reflector 131 connected to one end of the first support rod 133 is supported by the first support rod 133 and the second support rod 134. The support rod 135 is composed of one rod or a plurality of rods to support the sub-reflector 131. In Figure 1 In the example of , three pairs of support rods 135 (one pair of which is covered on the back and not shown) are arranged at equal intervals. Figure 1 In the example of FIG. 1 , the first support rod 133 and the second support rod 134 are described as a pair of rods. However, the invention is not limited thereto, and the number of the second support rods 134 may be reduced or increased relative to the number of the first support rods 133 .

[0037] In this embodiment, a case where a small SAR satellite has a Cassegrain antenna whose main reflector 132 is formed in a parabolic shape is described as the spacecraft 1. However, the present invention is not limited to this, and other parabolic antennas such as Gregorian antennas or planar antennas may be provided.

[0038] Figure 2 This is a block diagram showing the structure of the spacecraft 1 according to the first embodiment of the present disclosure. The spacecraft 1 does not need to include Figure 2 All the components shown may be partially omitted, or other components may be added. For example, the spacecraft 1 may be equipped with a plurality of power supply units 200 and / or a plurality of communication units 100 .

[0039] according to Figure 2 The spacecraft 1 includes a control unit, a power unit 200 and a communication unit 100. The control unit includes a memory 310, a processor 320 and a sensor 330. The power unit 200 includes a power control circuit 210, a battery 220 and a solar panel 230. The communication unit 100 includes a communication control circuit 170, a transmitter 110, a receiver 140, a radiator 120 and a reflector 130. The components are electrically connected to each other via control lines and data lines.

[0040] The memory 310 is composed of a RAM, a ROM, a nonvolatile memory, a HDD, etc., and functions as a storage unit. The memory 310 stores instruction commands for various controls of the spacecraft 1 of the present embodiment as a program. As an example, the memory 310 appropriately stores an image of the outside of the spacecraft 1 captured by a camera (not shown), observation values ​​obtained by using the communication unit 100 as a radar, information received from a ground station via the communication unit 100 or information sent to a ground station via the communication unit 100, and detection information of the sensor 330 etc. required for the attitude and travel control of the spacecraft 1.

[0041] The processor 320 functions as a control unit that controls the spacecraft 1 according to the program stored in the memory 310. Specifically, the power supply unit 200, the communication unit 100, the sensor 330, etc. are controlled according to the program stored in the memory 310. As an example, the processor 320 performs control related to generating information to be sent to a ground station or other spacecraft via the communication unit 100, and performing observation by transmitting radio waves to an observation object and receiving its reflected waves by using the communication unit 100 as a radar.

[0042] As an example, the sensor 330 may include a gyro sensor, an acceleration sensor, a position sensor, a speed sensor, a star sensor, etc. required for controlling the movement and attitude of the spacecraft 1, a temperature sensor, an illumination sensor, an infrared sensor, etc. for observing the external environment of the spacecraft 1, and a temperature sensor, an illumination sensor, etc. for measuring the internal environment of the spacecraft 1. The detected information and data are appropriately stored in the memory 310 for control by the processor 320, or sent to a base station on the ground via the communication unit 100.

[0043] As an example, the actuator 340 may include a magnetic torquer, a reaction wheel, a CMG (control moment gyro), etc. The actuator 340 receives an instruction from the processor 320 to obtain a torque or thrust for attitude control of the spacecraft 1 and functions as a propulsion unit.

[0044] The power supply unit 200 includes a power supply control circuit 210, a battery 220, and a solar panel 230, and functions as a power supply unit. The power supply control circuit 210 is connected to the battery 220 to control the charging and discharging of the power of the battery 220. The battery 220 is controlled by the power supply control circuit 210, and is charged with the power generated by the solar panel 230, and stores the power to be provided to the computer 301 in the main body 300, the communication unit 100 and other driving systems.

[0045] The communication unit 100 includes a communication control circuit 170, a transmitter 110, a receiver 140, a radiator 120, and a reflector 130, and functions as a communication unit. The communication control circuit 170 performs signal encoding and decoding and other processing in order to send and receive information to and from a ground station or other spacecraft via the connected radiator 120. The transmitter 110 includes an oscillator, an amplifier, etc., and the amplifier amplifies the radio wave with a frequency of a specified frequency band generated by the oscillator. The amplified radio wave is transmitted to the reflecting surface of the reflector 130 via the radiator 120. In this embodiment, the communication unit 100 is used to transmit radio waves to the observed object and observe using its reflected waves. Therefore, the radio waves emitted from the radiator 120 are first reflected by the sub-reflector 131 constituting the reflector 130, and then emitted to the outside by the main reflector 132. On the other hand, the reflected wave received from the outside is received by the receiver 140 through the opposite path.

[0046] In this embodiment, only a communication unit having a pair of reflectors, namely, the sub-reflector 131 and the main reflector 132, is described as the communication unit 100. The communication unit 100 can be adjusted as desired to include frequencies such as a frequency band below 8 GHz, a microwave frequency band such as an 8 GHz to 12 GHz frequency band (so-called X band), a frequency band such as a 12 GHz to 18 GHz frequency band (so-called Ku band), a millimeter wave frequency band above 30 GHz, and a submillimeter wave frequency band above 300 GHz.

[0047] Figure 3 1 is a block diagram showing the structure of the transmitter 110 according to the first embodiment of the present disclosure. Specifically, Figure 3 It is functionally shown Figure 2 FIG. 1 is a diagram showing the internal structure of the transmitter 110. Figure 3 , the transmitter 110 includes an oscillator 111 , an amplifier 112 , a synthesizer 113 and a low-pass filter 114 .

[0048] As an example, the oscillator 111 is Figure 1 The oscillator 111 is arranged inside the main body 300. The oscillator 111 outputs a high-frequency signal as an electric wave for transmitting a signal or the like. In the present embodiment, the oscillator 111 outputs an electric wave, which includes at least any frequency in a frequency band below 8 GHz, a microwave frequency band such as a frequency band of 8 GHz to 12 GHz (so-called X band), a frequency band of 12 GHz to 18 GHz (so-called Ku band), a millimeter wave frequency band above 30 GHz, and a submillimeter wave frequency band above 300 GHz, preferably includes at least any frequency in a frequency band below 8 GHz, a microwave frequency band such as a frequency band of 8 GHz to 12 GHz (so-called X band), a frequency band of 12 GHz to 18 GHz (so-called Ku band), and more preferably includes at least any frequency in a frequency band of 8 GHz to 12 GHz (so-called X band).

[0049] The amplifier 112 is electrically connected to the oscillator 111, and amplifies the power of the radio wave output from the oscillator 111. In the present embodiment, as an example, the data of the observation object is observed by transmitting radio waves toward an external observation object and receiving reflected waves reflected by the observation object. Therefore, a very high transmission power is required. In the present embodiment, the amplifier 112 amplifies to become a power of 500W to 5000W, preferably a transmission power of 700W to 2500W, and more preferably a transmission power of 1000W to 1500W. The amplifier 112 can be formed by combining one or more amplifiers according to the output. The specific structure of the amplifier 112 is described later. In addition, the output of the amplifier is only an example. For example, the upper and lower limits of each range only define the current required power. Regardless of the output exceeding the upper limit or the output below the lower limit, by applying the structure of the present embodiment, the desired effect such as the heat dissipation effect can be obtained.

[0050] When a plurality of amplifiers are combined to form the amplifier 112, a synthesizer 113 is electrically connected to the amplifier 112, and the synthesizer 113 synthesizes the radio waves output from the respective amplifiers into one carrier wave. A low-pass filter 114 is electrically connected to the synthesizer 113, and the low-pass filter 114 is used to extract only the low-frequency component from the radio wave output from the synthesizer 113 and remove it. This is to remove radio waves in a frequency band whose use is restricted due to radio wave laws, etc. The radio wave that has passed through the low-pass filter 114 is output to Figure 2 The radiator 120 is shown, and the radiation is emitted to the outside via the radiator 120 .

[0051] Here, as described above, the amplifier 112 included in the transmitter 110 uses a high-output power amplifier. Therefore, the amplifier 112 will radiate heat due to operation, which will have an adverse effect on surrounding electronic equipment. Furthermore, when the amplifier 112 reaches a high temperature, the risk of the components constituting the amplifier 112 themselves also malfunctioning becomes higher. Therefore, in the present embodiment, the amplifier 112 is arranged in the external packaging portion of the main body 300 and exposed to outer space. In this way, it can be away from other electronic devices such as the processor 320 stored in the internal storage space of the main body 300, and the adverse effects on other electronic devices can be reduced. In addition, in the case where the spacecraft 1 is orbiting in a satellite orbit, since the amplifier 112 is exposed to outer space, it can also be effectively cooled.

[0052] Figure 4 1 is a side view showing the general structure of a spacecraft 1 according to a first embodiment of the present disclosure. Specifically, Figure 4 This is a diagram in which a portion of the structure of the main reflector 132 is omitted in order to illustrate the configuration position of the amplifier 112. Figure 5 1 is a plan view showing the general structure of a spacecraft 1 according to a first embodiment of the present disclosure. Specifically, Figure 5 In order to illustrate the arrangement position of the amplifier 112 , a part of the structure of the sub-reflector 131 is omitted in this diagram.

[0053] First, according to Figure 4 A hub 139 is arranged on the upper surface of a main body 300 formed of an octahedron having a hexagonal upper surface and a bottom surface. The hub 139 is formed in a substantially cylindrical shape, and ribs 136 constituting a main reflector 132 are arranged at equal intervals and radially on its outer circumference. As an example, the cross section of the hub 139 when viewed from the direction along the central axis X is substantially circular. The amplifier 112 is arranged at a substantially central position of the circular hub 139 and on the same surface (i.e., the upper surface) of the main body 300 as the surface on which the hub 139 is arranged. Therefore, the amplifier 112 is not accommodated in the internal storage space of the main body 300, but is arranged on the surface exposed to the outer space.

[0054] In addition, in this embodiment, as an example, the radiator 120 is composed of a horn radiator, but it is of course not limited to this form. In addition, the sub-reflector 131 is separated from the horn radiator 120 by a predetermined interval and arranged by the support rod 135 composed of the first support rod 133, the second support rod 134 and the joint 138. In this embodiment, the amplifier 112 is arranged on the line connecting the radiator 120 and the sub-reflector 131 (that is, the line of the central axis X) and close to the radiator 120. In addition, the arrangement position of the amplifier 112 and the radiator 120 is only an example, and it is of course not necessary to arrange them on the line of the central axis X.

[0055] Generally, the radio waves amplified by the amplifier 112 are electrically transmitted via a coaxial cable and / or a waveguide before reaching the radiator 120 via various electronic components that are electrically connected. During this transmission process, power loss occurs when passing through various electronic components and coaxial cables, and its transmission efficiency is reduced. Therefore, by arranging the amplifier 112 on the line connecting the radiator 120 and the sub-reflector 131 (that is, on the line of the central axis X) and close to the radiator 120 as in this embodiment, the wiring distance using the coaxial cable and / or the waveguide can be minimized, and its power loss can be reduced.

[0056] Next, according to Figure 5 The hub 139 is formed in a substantially circular shape when viewed from above, and is disposed on the upper surface of the main body 300 formed in a hexagonal shape. In addition, the center of the hub 139 is configured to pass through the central axis X. A plurality of ribs 136 constituting the main reflector 132 are arranged at equal intervals on the outer peripheral surface of the hub 139. In this embodiment, although Figure 5 Although not shown in the figure, the sub-reflector 131 is arranged so that the center of the sub-reflector 131 is located on the central axis X of the hub 139. Therefore, the radiator 120 that radiates radio waves to the sub-reflector 131 is also arranged on the central axis of the hub 139.

[0057] In this embodiment, amplifier 112 is disposed on the hexagonal upper surface of body 300 and is disposed directly below radiator 120 for the purpose of shortening the wiring distance between amplifier 112 and radiator 120. Therefore, amplifier 112 is disposed substantially at the center of hub 139.

[0058] 2. Structure of the amplifier

[0059] Figure 5 1 is a plan view showing the general structure of a spacecraft 1 according to a first embodiment of the present disclosure. Figure 6 1 is a side view showing the schematic structure of the amplifier 112 according to the first embodiment of the present disclosure. Figure 5 and Figure 6 , the amplifier 112 is composed of four amplifiers 112-1a to 112-1d. Figure 5 and Figure 6 In the example, the four amplifiers 112-1a to 112-1d are arranged to form the sides of a rectangular parallelepiped. Furthermore, the amplifiers 112-1a to 112-1d are supported by a frame 112-2, and the frame 112-2 is arranged to connect the amplifiers 112-1a to 112-1d. That is, although Figure 5 and Figure 6Although not shown in the figure, the amplifiers 112-1a to 112-1d are fixed to the upper surface of the main body 300 via the frame 112-2. Figure 5 and Figure 6 In the example of , four amplifiers are arranged to form the side of the rectangular parallelepiped, but the number of amplifiers used may be one or more than four. It can be appropriately adjusted according to the desired power.

[0060] exist Figure 5 and Figure 6 In the example, at least a portion of the amplifier 112 (specifically, the outer surfaces 112-3a to 112-3d exposed to outer space) is covered with silver-plated Teflon, aluminum-plated Teflon, indium oxide, indium tin oxide, white paint, black paint, or a combination thereof (preferably silver-plated Teflon or aluminum-plated Teflon) to further improve the heat dissipation effect. In addition, the covering can be formed by any method as desired, such as pasting a coating material in a sheet form, or spraying a coating agent in a liquid form. In addition, in Figure 5 and Figure 6 In the example, only the surface on one side exposed to outer space is covered, but it is not limited to this, and the upper surface or the inner surface may also be covered.

[0061] One end of the four amplifiers 112-1a to 112-1d is connected to each amplifier 112-1a to 112-1d, and the other end is connected to the synthesizer 113 via a coaxial cable and / or a waveguide (not shown) connected to the synthesizer 113. Then, the synthesizer 113 synthesizes the radio waves that have been power-amplified by the amplifiers 112-1a to 112-1d. Figure 5 and Figure 6 In the example, a horn-shaped radiator 120 is arranged on the central axis X which is the center of each amplifier 112-1a to 112-1d arranged to form a rectangular parallelepiped. The synthesizer 113 and the radiator 120 are arranged on the upper surface side of the main body 300 together with the amplifiers 112-1a to 112-1d through the frame 112-2.

[0062] In addition, in the present embodiment, adjacent to the radiator 120, another communication unit 180 is also fixed to the frame 112-2. The communication unit 180 has a horn-shaped radiator, and as an example, is used for communication in the 12 GHz to 18 GHz frequency band (so-called Ku band) used when sending data from the spacecraft 1 to the ground station. In this case, unlike the communication unit 100 for observation, which needs to receive the reflected wave from the observation object, it is sufficient to make the radio wave reach the ground station, so a high-output amplifier like the communication unit 100 is not required. Therefore, the communication unit 180, for example, only includes a low-output amplifier.

[0063] As described above, in this embodiment, the amplifier 112 is arranged on the surface of the main body 300 exposed to outer space. As a result, not only can the heat dissipation effect of the heat generated by the amplifier 112 be improved, but also the amplifier 112 as a heat source can be kept away from other electronic devices, thereby reducing their adverse effects. In addition, by improving the heat dissipation effect of the amplifier 112, the risk of failure of the components constituting the amplifier 112 itself can also be reduced. In addition, in particular in a small SAR satellite, the limited storage space of the main body 300 can be effectively utilized.

[0064] <Other Implementation Methods>

[0065] In the first embodiment, the amplifier 112 is arranged on the antenna arrangement surface side of the main body 300. However, the present invention is not limited thereto, and the amplifier 112 may be arranged on other surfaces of the main body 300. For example, by arranging the amplifier 112 on the lower surface of the main body 300, that is, on the surface exposed to outer space, the heat dissipation effect of the amplifier 112 can be improved as in the first embodiment.

[0066] In the first embodiment, the communication unit 100 having a so-called Cassegrain type antenna having a sub-reflector 131 in addition to the main reflector 132 has been described. However, the communication unit 100 is not limited to this, and may be a Gregorian type communication unit, a parabolic communication unit that radiates radio waves from the front surface of the reflector 121, or a communication unit having a planar antenna.

[0067] The components described in the embodiments may be appropriately combined or replaced.

[0068] Description of symbols

[0069] 1: spacecraft; 100: communication unit; 200: power supply unit; 300: main body.

Claims

1. A spacecraft comprising: A main body having a storage space inside for storing electronic equipment; an oscillator configured to output a radio wave having a frequency including a predetermined frequency band; an amplifier, which is arranged in an external package of the main body so as to be exposed to outer space and is configured to amplify the power of the radio wave output by the oscillator; and an antenna, which is arranged on the external package of the main body and is used to transmit the radio waves to the outside with the power amplified by the amplifier, The amplifier and the antenna are fixed to the same surface side of the main body in a manner aligned along a central axis of the antenna.

2. The spacecraft according to claim 1, wherein: The prescribed frequency band is a microwave frequency band.

3. The spacecraft according to claim 1, wherein: The specified frequency band is 8 GHz to 12 GHz.

4. The spacecraft according to claim 1, wherein: The amplifier amplifies the electric power of the radio wave so as to make the electric power into 500W to 5000W.

5. The spacecraft according to claim 1, wherein: The antenna is configured to receive radio waves that are emitted from the antenna and reflected by an observation target object.

6. The spacecraft according to claim 1, wherein: The amplifier is formed by combining a plurality of amplifiers. The spacecraft further includes a synthesizer that synthesizes the electric waves output from the plurality of amplifiers.

7. The spacecraft according to claim 1, wherein: The main body is formed into a polyhedron shape, The antenna is arranged on at least one side of the main body. The amplifier is disposed on the side where the antenna is disposed.

8. The spacecraft according to claim 1, wherein: The antenna comprises: a radiator for emitting the radio waves with the electric power amplified by the amplifier; a main reflector that emits the radio waves toward the outside; as well as a sub-reflector that reflects the radio waves emitted from the radiator toward the main reflector, The amplifier is arranged on a line connecting the radiator and the sub-reflector.

9. The spacecraft according to claim 8, wherein: The spacecraft includes a hub, which is arranged on the surface of the main body on the side of the sub-reflector, and the cross section of the hub is formed into a circular shape, an elliptical shape or a polygonal shape, and is configured to connect the ribs constituting the main reflector. The amplifier is configured to be located approximately in the center of the hub.

10. The spacecraft according to claim 1, wherein: At least a portion of the amplifier is covered with silver-coated Teflon, aluminum-coated Teflon, indium oxide, indium tin oxide, white paint, black paint, or a combination thereof.

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