Storage tank, spacecraft and method of using a storage tank

Abstract

The application relates to the technical field of on-orbit refueling, and discloses a storage tank, a spacecraft and a storage tank use method. The storage tank comprises a barrel body and a head. The barrel body comprises at least two barrel segments. The barrel segments are sequentially nested along the axial direction of the barrel body. The head comprises a first head and a second head. The first head and the second head respectively close the two ends of the barrel body. The head and the barrel body surround a cavity. At least part of the barrel segments can be extended and retracted along the axial direction to change the volume of the storage tank. On the one hand, during launching, the storage tank can reduce its volume by using the contraction of the barrel segments, thereby reducing the launch envelope of the spacecraft and improving the space utilization rate inside the fairing. On the other hand, after the spacecraft is on orbit, propellant is added into the cavity. The barrel segments can be extended under the pressure of the propellant, thereby providing a large-capacity cavity for the propellant. When the volume of the propellant changes, the barrel segments can automatically extend and retract, so that the volume of the cavity matches the volume of the propellant.

Description

Technical Field

[0001] This invention relates to the field of on-orbit refueling technology, specifically to tanks, spacecraft, and methods of using tanks. Background Technology

[0002] In-orbit refueling technology is of great significance for extending spacecraft lifespan and reducing costs. Propellant tanks, as the core component of in-orbit refueling, are mainly used for storing and managing propellants. In existing technologies, to meet the requirements of large-capacity propellant refueling, tanks often have large external dimensions, but this also encroaches on the usable space of other structures inside the fairing, reducing space utilization. Summary of the Invention

[0003] In view of this, the present invention provides a storage tank, a spacecraft, and a method for using the storage tank to solve the problem of excessive space occupied by the storage tank.

[0004] In a first aspect, the present invention provides a storage tank, the storage tank comprising a cylindrical body and end caps, the cylindrical body comprising at least two cylindrical segments, each of the cylindrical segments being nested sequentially along the axial direction of the cylindrical body, the end caps comprising a first end cap and a second end cap, the first end cap and the second end cap respectively closing both ends of the cylindrical body, the end caps and the cylindrical body surrounding to form a cavity, wherein at least a portion of the cylindrical segments are capable of extending and retracting along the axial direction to change the volume of the storage tank.

[0005] Beneficial effects: On the one hand, during launch, the tank can reduce its volume by contracting the cylindrical section, thereby reducing the launch envelope of the spacecraft and improving the space utilization rate inside the fairing; on the other hand, after the spacecraft is in orbit, propellant is added to the cavity, and the cylindrical section can extend under the pressure of the propellant, thereby providing a large-capacity cavity for the propellant. Furthermore, when the volume of the propellant changes, the cylindrical section can automatically expand and contract to match the volume of the cavity with the volume of the propellant.

[0006] In one alternative embodiment, the tank includes a limiting component connected between the two cylindrical sections, the limiting component being used to limit the distance between the two cylindrical sections.

[0007] Beneficial effect: Setting a limit component can restrict the extension and retraction of the cylinder segment, preventing two connected cylinder segments from accidentally separating.

[0008] In one alternative embodiment, the limiting assembly includes connecting lugs, guide rods, and rod caps, the connecting lugs protruding from the outer wall of the cylindrical section, the guide rods extending along the axial direction and passing through the two connecting lugs, and the rod caps being disposed at both ends of the guide rods.

[0009] Beneficial effects: The contact between the two connecting lugs can limit the retraction stroke of the cylinder section, and the contact between the rod cap and the connecting lugs can limit the extension stroke of the cylinder section, thus achieving bidirectional limitation of the stroke. At the same time, the guide rod can also play a guiding role during the extension and retraction process.

[0010] In one alternative embodiment, the limiting component includes a driver that is drively connected to the guide rod and is used to drive the guide rod to extend or retract.

[0011] Beneficial effects: The guide rod is designed to extend and retract actively. During launch, the guide rod retracts to keep the propellant tank in a stable compressed state. After launch, the guide rod extends to allow propellant to be loaded into the tank. After loading, the tank volume can be actively controlled, enabling comprehensive management of the propellant inside the tank.

[0012] In one alternative embodiment, the tank includes a seal disposed between the sidewalls of two adjacent cylindrical sections.

[0013] Beneficial effect: The seals prevent propellant from leaking between the barrel sections.

[0014] In one alternative embodiment, an annular sealing groove is formed on the outer wall of the cylindrical section, and the sealing element is disposed within the sealing groove.

[0015] Beneficial effects: On the one hand, the sealing element is set on the outer surface of the cylinder section, which facilitates assembly; on the other hand, the sealing groove can constrain the sealing element and prevent it from deviating from its original position during expansion and contraction.

[0016] In one alternative embodiment, the diameter of the cylindrical section gradually decreases from the end where the first end cap is located to the end where the second end cap is located.

[0017] Beneficial effects: The gradually decreasing design makes the diameters of each cylinder section different. During contraction, the cylinder sections are arranged in order of increasing size in the radial direction and staggered from each other, which helps to reduce the axial compression size of the storage tank.

[0018] In one alternative embodiment, the first end cap has a filling and discharging port, and the first end cap is used to be fixedly installed in the spacecraft.

[0019] Beneficial effects: By using the refueling and discharge port for refueling operations, the position of the refueling and discharge port remains stable during the refueling process, which can reduce the risk of propellant leakage from the refueling and discharge port.

[0020] Secondly, the present invention also provides a spacecraft including the tank provided by the present invention.

[0021] Beneficial effects: The spacecraft provided by the present invention includes a storage tank, and therefore also has the beneficial effects brought by the storage tank, which will not be elaborated here.

[0022] Thirdly, the present invention also provides a method for using a propellant tank, the method of using the propellant tank provided by the present invention comprising: before the spacecraft is in orbit, placing the propellant tank in a retracted state and without propellant loading; and after the spacecraft is in orbit, loading propellant into the propellant tank.

[0023] Beneficial effects: By compressing the propellant tank, the launch envelope of the spacecraft containing the tank can be reduced, allowing the launch vehicle to place more spacecraft inside the fairing, thereby improving the space utilization rate inside the fairing; the cylinder section can extend during the refueling process, so that the volume of the cavity matches the volume of the propellant, thereby ensuring the normal use of the tank. Attached Figure Description

[0024] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0025] Figure 1 This is a front half-sectional view of a storage tank according to an embodiment of the present invention, showing the state of the storage tank during compression; Figure 2 for Figure 1 The illustrated tank embodiment is shown in a front half-sectional view, illustrating the state of the tank during expansion. Figure 3 for Figure 1 Side view diagram from direction A; Figure 4 for Figure 1 Side view diagram from direction B; Figure 5 This is a front half-sectional view of a storage tank according to another embodiment of the present invention, showing an electrically driven guide rod; Figure 6 This is a schematic diagram of the structure of a spacecraft according to an embodiment of the present invention, which shows one way in which the storage tank is installed in the spacecraft.

[0026] Explanation of reference numerals in the attached figures: 1. Storage tank; 101. Cylindrical section; 102. First end cap; 1021. Filling / discharging port; 103. Second end cap; 104. Cavity; 1051. Connecting lug; 1052. Guide rod; 1053. Rod cap; 1054. Motor; 1061. Seal; 1062. Sealing groove; 2. Mounting platform; 3. Load. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] It should be understood that the terminology used herein is for the purpose of describing particular exemplary embodiments only and is not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms "a," "an," and "comprising" as used herein may also mean including the plural forms. The terms "comprising," "including," and "having" are inclusive and therefore indicate the presence of the stated features, elements, and / or components, but do not exclude the presence or addition of one or more other features, elements, components, and / or combinations thereof.

[0029] Although terms such as "first," "second," etc., may be used in this document to describe multiple elements, components, regions, layers, and / or segments, these elements, components, regions, layers, and / or segments should not be limited by these terms. These terms may be used only to distinguish one element, component, region, layer, or segment from another. Unless the context clearly indicates otherwise, terms such as "first," "second," and other numerical terms used herein do not imply order or sequence. Furthermore, in the description of this application, unless otherwise expressly specified and limited, the terms "set up" and "connected" should be interpreted broadly; for example, they may refer to a fixed connection, a detachable connection, or an integral connection; they may refer to a direct connection or an indirect connection via an intermediate medium. Those skilled in the art will understand the specific meaning of the above terms in this application based on the specific circumstances.

[0030] For ease of description, spatial relative terms may be used in the text to describe the relationship of one element or feature relative to another element or feature, as shown in the figure. These relative terms include, for example, "end," "length," "inner," "outer," etc. Such spatial relative terms are intended to include different orientations of the mechanism in use or operation, in addition to those depicted in the figure. For example, if the mechanism in the figure is flipped, then an element described as "below other elements or features" or "below other elements or features" will subsequently be oriented as "above other elements or features" or "above other elements or features." Therefore, the example term "below" can include both upper and lower orientations. The mechanism may be otherwise oriented (rotated 90 degrees or in other directions), and the spatial relative descriptors used in the text will be interpreted accordingly.

[0031] Spacecraft (such as satellites) use propellant tanks to receive and supply propellant in orbit, thereby improving the spacecraft's maneuverability and extending its operational life. Related technologies tend to use large-capacity tanks, which can load more propellant at once, reducing the frequency of spacecraft refueling and facilitating spacecraft operation and maintenance. However, the space within the launch vehicle's fairing is limited; increasing the tank volume reduces space utilization and impacts the launch vehicle's launch efficiency.

[0032] In addition, the tanks in related technologies often adopt a rigid, fixed-capacity design. By inputting compressed gas into the tank, the tank can continuously deliver liquid propellant without entrainment to the downstream system. For this purpose, high-pressure gas cylinders, pressure reducers and other devices are required, which further reduces the space utilization rate inside the fairing.

[0033] The following is combined Figures 1 to 4 The following describes embodiments of the present invention.

[0034] Reference Figure 1 and Figure 2 According to an embodiment of the present invention, in a first aspect, a storage tank 1 is provided. The storage tank 1 includes a cylindrical body and end caps. The cylindrical body includes at least two cylindrical segments 101, each of which is nested sequentially along the axial direction of the cylindrical body. The end caps include a first end cap 102 and a second end cap 103, which respectively close the two ends of the cylindrical body. The end caps and the cylindrical body surround and form a cavity 104. At least a portion of the cylindrical segments 101 are capable of extending and retracting along the axial direction to change the volume of the storage tank 1.

[0035] It is understood that the tank 1 of the present invention is a component of the spacecraft and is exposed to the outside of the spacecraft. Figure 1 This shows the state when the cylindrical section 101 contracts and the volume of the storage tank 1 decreases. Figure 2 The diagram shows the state when the cylindrical section 101 extends and the volume of the storage tank 1 increases.

[0036] On the one hand, during launch, the tank 1 can reduce its volume by contracting the cylindrical section 101, thereby reducing the launch envelope of the spacecraft (that is, the envelope formed by the spacecraft during launch) and improving the space utilization rate inside the fairing. On the other hand, after the spacecraft is in orbit, propellant is added to the cavity 104. The cylindrical section 101 can extend under the pressure of the propellant, thereby providing a large-capacity cavity 104 for the propellant. Furthermore, when the volume of the propellant changes (e.g., when the propellant is consumed or when the propellant expands or contracts due to thermal expansion or contraction), the cylindrical section 101 can automatically expand and contract to match the volume of the cavity 104 with the volume of the propellant.

[0037] Furthermore, since the volume of the cavity 104 can be changed according to the volume change of the propellant, the pressure of the tank 1 can be kept constant without compressing the gas. The spacecraft can omit high-pressure gas cylinders, pressure reducers and other devices, further reducing the launch envelope of the spacecraft and improving the space utilization rate inside the fairing.

[0038] Understandably, tank 1 also has a filling and discharging port 1021 for filling and discharging propellant.

[0039] In some embodiments, the first end cap 102 has a filling / discharging port 1021, and the first end cap 102 is used to be fixedly installed in the spacecraft.

[0040] During the refueling process, the service spacecraft docks with the spacecraft containing tank 1 and injects propellant through the refueling and discharge port 1021. Since the first end cap 102 is fixedly installed in the spacecraft, the position of the refueling and discharge port 1021 can remain stable during the refueling process, thereby avoiding the interface from separating and reducing the risk of propellant leakage from the refueling and discharge port 1021.

[0041] In some embodiments, the tank 1 includes a limiting component connected between two cylindrical sections 101, which limits the distance between the two cylindrical sections 101. The limiting component can restrict the extension and retraction of the cylindrical sections 101, thereby maintaining the connection between the cylindrical sections 101 and preventing the two connected cylindrical sections 101 from accidentally separating.

[0042] Optionally, in some embodiments, the limiting assembly includes a connecting ear 1051, a guide rod 1052, and a rod cap 1053. The connecting ear 1051 protrudes from the outer wall of the cylindrical section 101, the guide rod 1052 extends axially and passes through the two connecting ears 1051, and the rod cap 1053 is disposed at both ends of the guide rod 1052.

[0043] The contact between the two connecting lugs 1051 can limit the retraction stroke of the cylindrical section 101, and the contact between the rod cap 1053 and the connecting lugs 1051 can limit the extension stroke of the cylindrical section 101, thereby achieving bidirectional limitation of the stroke. At the same time, the guide rod 1052 can also play a guiding role during the extension and retraction process.

[0044] Specifically Figure 1 and Figure 2 In the illustrated embodiment, the connecting lug 1051 has through holes, and the bolt passes through the two through holes and is screwed on with a nut, thereby connecting the connecting lug 1051 of the two cylindrical sections 101. At this time, the shank of the bolt is the guide rod 1052 of the limiting component, and the head of the bolt and the nut are the rod cap 1053 of the limiting component.

[0045] Reference Figure 3 and Figure 4 Multiple connecting lugs 1051 can be equidistantly arranged along the circumference on a single cylindrical section 101, thereby connecting two cylindrical sections 101 using multiple guide rods 1052. This improves the guiding effect of the guide rods 1052 and also allows the cylindrical section 101 to be subjected to more uniform force during positioning, thus avoiding stress concentration.

[0046] In addition, Figure 3 and Figure 4 In the illustrated embodiment, the cylindrical segment 101 where the first end cap 102 is located (here referred to as the reference segment) serves as the limiting reference. The reference segment has eight connecting lugs 1051 equidistantly spaced along its circumference. The remaining cylindrical segments 101 (here referred to as movable segments) each have two symmetrical connecting lugs 1051, and are connected to the reference segment via guide rods 1052. This ensures that the travel range of each movable segment is uniformly limited by the connecting lugs 1051 of the reference segment. However, the connection method of the guide rods 1052 is not limited to this; the guide rods 1052 can also be connected between two adjacent cylindrical segments 101, and this invention does not impose any restrictions on this.

[0047] The limiting component can also be constructed in other ways, as long as it can constrain the stroke of the cylinder section 101.

[0048] For example, in some embodiments not shown, the inner wall of the cylindrical section 101 may form an annular inner flange along the radial protrusion, and the outer wall of the cylindrical section 101 may form an annular outer flange along the radial protrusion. The inner flange of one cylindrical section 101 and the outer flange of another cylindrical section 101 are in contact with each other, thereby constraining the stroke.

[0049] For example, in some embodiments not shown, two cylinder sections 101 can be connected by a linkage mechanism, thereby constraining the extension stroke of the cylinder section 101.

[0050] Furthermore, the limiting component may optionally include a driver that can actively act on the cylinder section 101, facilitating full management of the storage tank 1.

[0051] Exemplary, in some embodiments not shown, the driver is driven to connect to the guide rod 1052, and the driver is used to drive the guide rod 1052 (in which case the guide rod 1052 can be a hydraulic rod or other telescopic structure) to extend or retract. Thus, the limiting assembly can actively retract the cylinder section 101, ensuring that the propellant is always at the outlet of the tank 1.

[0052] Furthermore, during rocket launch, the guide rod 1052 can actively retract to apply force to the cylinder section 101, ensuring that the propellant tank 1 remains compressed during launch and will not accidentally extend due to acceleration or impact. After the spacecraft is in orbit, the guide rod 1052 receives the corresponding command and extends to its normal working length, thereby allowing the propellant tank 1 to receive propellant.

[0053] Exemplarily, in some embodiments, reference is made to Figure 5 The guide rod 1052 is a lead screw driven by a motor 1054. The motor 1054 is mounted on one of the connecting lugs 1051. The mounting base of the motor 1054 serves as one of the rod caps 1053. The slider serves as the other rod cap 1053 and is mounted on the other connecting lug 1051 and sleeved on the guide rod 1052. As the guide rod 1052 rotates, the slider moves along the guide rod 1052, thereby driving the cylinder section 101 to extend and retract.

[0054] In some embodiments, the tank 1 includes a seal 1061 disposed between the sidewalls of two adjacent cylinder sections 101. The seal 1061 forms a dynamic seal between the adjacent cylinder sections 101 to prevent propellant leakage between the cylinder sections 101.

[0055] Specifically, in Figure 2 In the illustrated embodiment, an annular sealing groove 1062 is formed on the outer wall of the cylindrical section 101, and a sealing element 1061 is disposed within the sealing groove 1062. On the one hand, the sealing element 1061 is disposed on the outer surface of the cylindrical section 101 for easy assembly; on the other hand, the sealing groove 1062 can constrain the sealing element 1061 and prevent the sealing element 1061 from deviating from its original position during expansion and contraction.

[0056] It should be pointed out that, in Figure 2 The central seal 1061 is schematically represented by a circular sealing ring, but the actual seal 1061 that can be used is not limited to this. For example, a lip seal can also be considered to improve the dynamic sealing effect.

[0057] In some embodiments, the diameter of the cylindrical section 101 gradually decreases from the end where the first end cap 102 is located to the end where the second end cap 103 is located. The gradually decreasing design makes the diameters of each cylindrical section 101 different from each other. During contraction, the cylindrical sections 101 are arranged in order of increasing diameter in the radial direction and staggered from each other, which helps to reduce the axial compression dimension of the storage tank 1. According to an embodiment of the present invention, in a second aspect, a spacecraft is also provided, the spacecraft including the tank 1 of the present invention.

[0058] The spacecraft also has the same beneficial effects as tank 1, which will not be elaborated here.

[0059] Furthermore, as mentioned earlier, since the volume of tank 1 can vary, the spacecraft does not need to use a compression-type gas supply method, thus eliminating the need for high-pressure gas cylinders and pressure reducers to provide compression gas, further reducing the spacecraft's launch envelope.

[0060] For example, refer to Figure 6 In some embodiments, the spacecraft includes a mounting platform 2 (the rest of the spacecraft structure is omitted here). The mounting platform 2 has a layered design; specifically, one side of the mounting platform 2 is used to mount the payload 3, and the other side is used to mount the propellant tank 1. The mounting platform 2 has a through mounting hole, and the end of the propellant tank 1 containing the first end cap 102 is embedded and fixed in the mounting hole, such that the filling and discharging port 1021 faces the end containing the payload 3 for refueling. During launch, the propellant tank 1 retracts, thus retracting entirely into the mounting hole, with the second end cap 103 located within the mounting hole, giving the spacecraft a compact launch envelope. After orbit, the second end cap 103 extends away from the payload 3 for refueling.

[0061] Optionally, the mounting platform 2 is provided with multiple storage tanks 1, which are arranged circumferentially to make full use of the space inside the fairing.

[0062] According to an embodiment of the present invention, a third aspect also provides a method for using a storage tank, the method being implemented based on the storage tank 1 of the present invention, the method comprising the following steps: Step S101: Before the spacecraft is in orbit, tank 1 is in a retracted state and without propellant.

[0063] Step S102: After the spacecraft is in orbit, propellant is added to tank 1.

[0064] Optionally, in some embodiments, step S101 specifically includes: Step S1011: Control the guide rod 1052 to retract so that the storage tank 1 is in a retracted state.

[0065] Active management of the propellant tank 1 using the guide rod 1052 helps to avoid accidents during launch, and also avoids the introduction of external or destructive structures (such as explosive bolts) to compress the propellant tank 1.

[0066] Optionally, in some embodiments, step S102 specifically includes: Step S1021: Control guide rod 1052 to elongate in response to propellant injection, so as to keep the pressure in tank 1 stable.

[0067] Specifically, after the spacecraft containing Tank 1 is in orbit, Tank 1 does not deploy immediately like payloads such as solar sails. Instead, it deploys during refueling. During refueling, the spacecraft containing Tank 1 establishes a communication connection with the service spacecraft, obtains propellant flow information from the service spacecraft, and actively adjusts the volume of Tank 1 based on this information to control the deployment speed of Tank 1 to match the propellant flow, making the refueling process smoother.

[0068] Optionally, in some embodiments, the method of using the storage tank further includes: Step S103: Control guide rod 1052 to extend or contract in response to pressure changes in tank 1, so as to keep the pressure in tank 1 stable.

[0069] Specifically, pressure changes may come from the use of propellant or thermal expansion and contraction. The spacecraft containing tank 1 monitors pressure changes and actively adjusts the volume of tank 1 based on this information, which helps to ensure that propellant is always supplied to the outside from the refueling and discharge port 1021 at a suitable pressure.

[0070] By compressing the propellant tank 1, the launch envelope of the spacecraft containing the propellant tank 1 can be reduced, allowing the launch vehicle to place more spacecraft inside the fairing, thereby improving the space utilization rate inside the fairing; the cylindrical section 101 can extend during the refueling process, so that the volume of the cavity 104 matches the volume of the propellant, thereby ensuring the normal use of the propellant tank 1.

[0071] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A spacecraft, characterized in that, include: A storage tank for receiving and supplying propellant in orbit includes a cylinder and a head. The cylinder includes at least two cylinder segments (101), each of which is nested sequentially along the axial direction of the cylinder. The head includes a first head (102) and a second head (103), which respectively close the two ends of the cylinder. The head and the cylinder together form a cavity (104). At least a portion of the cylindrical segment (101) is capable of telescoping along the axial direction to change the volume of the tank (1); the tank (1) includes a limiting assembly connected between two cylindrical segments (101) for limiting the distance between the two cylindrical segments (101); the limiting assembly includes a connecting lug (1051), a guide rod (1052), and a rod cap (1053); the connecting lug (1051) protrudes from the outer wall of the cylindrical segment (101); the guide rod (1052) extends along the axial direction and passes through the two connecting lugs (1051); the rod cap (1053) is disposed at both ends of the guide rod (1052); the limiting assembly includes a driver connected to the guide rod (1052) for driving the guide rod (1052) to telescop and extend; The installation platform (2) is used to set the load (3) on one side and the storage tank (1) is set on the other side. The mounting platform (2) has a through mounting hole. The end of the first end cap (102) of the tank (1) is embedded and fixed in the mounting hole. During launch, the tank (1) can retract and retract entirely into the mounting hole. The second end cap (103) is located in the mounting hole. After the spacecraft is in orbit, the second end cap (103) extends away from the load (3) for refueling. Before the spacecraft is in orbit, the guide rod (1052) is controlled to retract, so that the tank (1) is in a retracted state and not loaded with propellant; After the spacecraft is in orbit, propellant is added to the tank (1), and the guide rod (1052) is controlled to extend in response to the injection of propellant so as to keep the pressure inside the tank (1) stable; Furthermore, the guide rod (1052) is controlled to extend or contract in response to pressure changes within the tank (1) so that the pressure within the tank (1) remains stable.

2. The spacecraft according to claim 1, characterized in that, The storage tank (1) includes a seal (1061) disposed between the side walls of two adjacent cylindrical sections (101).

3. The spacecraft according to claim 2, characterized in that, The outer wall of the cylindrical section (101) is formed with an annular sealing groove (1062), and the sealing element (1061) is disposed in the sealing groove (1062).

4. The spacecraft according to claim 1, characterized in that, The diameter of the cylindrical section (101) gradually decreases from the end where the first end cap (102) is located to the end where the second end cap (103) is located.

5. The spacecraft according to claim 4, characterized in that, The first end cap (102) has a filling and discharging port (1021) and is used to be fixedly installed in the spacecraft.

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