Ultralight space launch vehicle fuselage and manufacturing method thereof

Abstract

The present invention relates to a space launch vehicle for transporting a load from the earth to a space orbit or to space and, more specifically, to a carbon composite ultralight space launch vehicle fuselage manufactured using a carbon fiber reinforced composite for the fuselage of the launch vehicle and a propellant tank accommodated in the fuselage, and a manufacturing method thereof.

Description

Ultra-light space launch vehicle body and manufacturing method thereof

[0001] The present invention relates to a space launch vehicle for transporting a payload from the ground to space orbit or space, and more specifically, to a fiber-reinforced composite ultra-light space launch vehicle body and a manufacturing method thereof, in which the body of the space launch vehicle and the propellant tank accommodated inside the body are manufactured using carbon fiber-reinforced composite.

[0002] A space launch vehicle is a rocket that carries a payload and lifts it away from the Earth to a designated location in space orbit. It refers to a propulsion system that utilizes action and reaction, or a flying object propelled by this rocket system.

[0003] A space launch vehicle consists of an engine that generates thrust, a propellant tank that stores propellant, avionics for attitude control and communications, a payload that is transported to orbit, and a fairing that protects the payload until it reaches orbit. The propellant tank accounts for more than half of the total structural weight, excluding the engine. Most propellant tanks are manufactured by machining and welding metal materials such as aluminum or stainless steel.

[0004] Most existing propellant tanks are built with a monocoque structure. This is because the monocoque is optimized for lightweight construction, consisting solely of a thin shell without a frame structure. Balloon tanks are the most extreme of these, maintaining their shape solely through internal pressurization but offering the advantage of being extremely lightweight.

[0005] Considering only weight, a spherical shape, which provides the lightest weight for a given volume, is ideal. However, due to limitations in the slenderness ratio, which takes into account the required propellant capacity and the aerodynamic performance of the launch vehicle, the main propellant tank is generally manufactured as a long cylinder. Propellant tanks for engine systems using turbopumps store propellant at a pressure of approximately 5 bar or less, and in this case, the internal pressure is relatively low, so the tank wall thickness can be reduced to reduce weight. On the other hand, propellant tanks for pressurized cycle engines store propellant at a high internal pressure of approximately 10 to 20 bar, so the tank wall thickness increases accordingly, resulting in increased weight.

[0006] Propellant tanks for space launch vehicles can be either a separate outer wall forming the fuselage structure and a tank containing the propellant, or an integral tank, where the tank itself forms part of the fuselage structure. In the case of an integral tank, where the tank itself is built as part of the fuselage, the internal pressure of the tank can support the load, allowing for lighter propellant tanks.

[0007] In addition, as the size of the projectile increases, the structural cost increases, so in small projectiles, it is very important to reduce the weight of the projectile tank.

[0008] Therefore, the development of technology to reduce the weight of the propellant tank, which accounts for a large proportion of the components of a space launch vehicle, is required.

[0009] The present invention has been devised to solve the above problems, and its purpose is to reduce the weight of the body structure including the propellant tank in a small space launch vehicle.

[0010] To this end, the present invention aims to provide a propellant tank including a cylinder made of a fiber-reinforced composite material and an upper dome and a lower dome inserted into the cylinder to form an integral tank with the fuselage.

[0011] An ultra-light space launch vehicle body according to one embodiment of the present invention comprises a space for accommodating fuel or oxidizer in the body of a space launch vehicle, the space for accommodating fuel or oxidizer being formed inside the body, the cylinder having both longitudinal sides open; and an upper dome and a lower dome respectively coupled to both sides of the cylinder, the cylinder being configured as an integral body that functions as a tank for filling fuel or oxidizer inside and at the same time forms the outer surface of the body.

[0012] In addition, the cylinder, upper dome, and lower dome are made of a laminate structure in which multiple layers of fiber-reinforced composite prepreg are laminated.

[0013] Additionally, the upper dome and the lower dome are inserted into the inside of the cylinder and combined.

[0014] In addition, the upper dome and the lower dome are adhesively bonded to the inner surface of the cylinder, and the upper dome and the lower dome further include a joint formed to extend longitudinally along the radially outer circumference, and the radially outer surface of the joint is in contact with the inner surface of the cylinder and bonded through an adhesive member.

[0015] In addition, the upper dome and the lower dome are formed with a first open hole for the inflow and outflow of fuel or oxidizer, and a boss made of a fiber-reinforced composite or metal material is bonded to the first open hole.

[0016] In addition, the boss is formed with a second open hole for the inflow and outflow of fuel or oxidizer, and a boss cap made of a fiber-reinforced composite or metal material is combined with the second open hole.

[0017] In addition, the boss is joined so that the radially outer circumference is connected to the circumference of the first open hole, and the outer surface is joined so as to be in contact with the inner surface of the first open hole.

[0018] Additionally, the length (H) of the above joint is calculated using the following formula 1.

[0019] (Formula 1)

[0020]

[0021] D: inner diameter of the cylinder, P: required internal pressure of the body, : Shear strength of adhesive, k: Safety factor for adhesive strength

[0022] In addition, the upper dome or lower dome is formed in the shape of an oval or torii-shaped dome, and is characterized in that the ratio of the major axis to the minor axis is 1: 0.3 to 1: 0.7.

[0023] In addition, the cylinder is provided with a baffle protruding radially inward on its inner surface, and the baffle is formed in a ‘ㄷ’ shape.

[0024] In addition, the baffle includes a bottom plate and a pair of side plates extending lengthwise on both sides of the bottom plate in the width direction, and the bottom plate has a bending surface formed by bending upward or downward on the radially inner or outer side, and the side plates have a joining surface formed by bending inward or outward in the circumferential direction on the radially outer side.

[0025] In addition, the boss is composed of a dome joint formed radially outer and joined to the dome, and a cap joint formed radially inner and joined to the boss cap.

[0026] In addition, the dome joint includes an adhesive surface formed for adhesive bonding with a dome in a predetermined area from a radially outer end to an inward end; a first bolting joint for bolting bonding with the dome on the radially inner side of the adhesive surface; and a first seal groove formed between the adhesive surface and the first bolting joint and into which a seal is inserted; and the cap joint includes a second bolting joint for bolting bonding with a boss cap on the radially outer side; and a second seal groove into which a second seal is inserted on the radially inner side of the second bolting joint.

[0027] Additionally, on the outside of the upper dome or lower dome, insulation material is provided for insulation.

[0028] According to another embodiment of the present invention, an ultra-light space launch vehicle body includes an oxidizer tank configured to contain an oxidizer and formed of the ultra-light space launch vehicle body of the above embodiment; a fuel tank configured to contain fuel and coupled to a lower side of the oxidizer tank; and an oxidizer transfer pipe penetrating the fuel tank to transfer the oxidizer to the lower side of the fuel tank.

[0029] In addition, the ultra-light space launch vehicle body further includes a ring joint provided between the lower side of the oxidizer tank and the end of the upper cylinder of the fuel tank to connect the oxidizer tank and the fuel tank.

[0030] A method for manufacturing an ultra-light space launch vehicle body according to one embodiment of the present invention comprises the steps of forming a cylinder using a fiber-reinforced composite; forming a dome using the fiber-reinforced composite; bonding a baffle to the cylinder; bonding a boss to the dome; and bonding the dome to the cylinder.

[0031] Additionally, the step of forming a cylinder using a fiber-reinforced composite and the step of forming a dome using a fiber-reinforced composite, or the step of bonding a baffle to the cylinder and the step of bonding a boss to the dome are performed sequentially, in reverse order or simultaneously.

[0032] A method for manufacturing an ultra-light space launch vehicle fuselage according to another embodiment of the present invention comprises: a first step of forming a cylinder using a fiber-reinforced composite; a second step of forming an upper dome using a fiber-reinforced composite; a third step of forming a lower dome using a fiber-reinforced composite; a fourth step of processing a baffle using a fiber-reinforced composite or a metal material; a fifth step of processing a boss using a fiber-reinforced composite or a metal material; a sixth step of bonding the baffle to the cylinder; a seventh step of bonding bosses to the upper dome and the lower dome; an eighth step of bonding the upper dome to one side of the cylinder; and a ninth step of bonding the lower dome to the other side of the cylinder.

[0033] Additionally, the first to fifth steps, the sixth and seventh steps, or the eighth and ninth steps are performed sequentially or in reverse order or randomly or simultaneously.

[0034] The carbon composite ultra-light space launch vehicle body of the present invention and its manufacturing method with the above-mentioned configuration have the effect of reducing the weight by 30% to 40% compared to aluminum alloy by applying a carbon fiber composite having a higher specific strength than aluminum alloy.

[0035] In addition, since a dome for forming a tank is inserted into the cylinder of the fuselage made of fiber-reinforced composite material and then an ultra-low temperature adhesive is injected to integrate them, the propellant tank and the fuselage are not manufactured and combined separately, but share the same cylinder structure, which has the effect of minimizing weight.

[0036] In particular, since the dome and cylinder are manufactured separately and then bonded together, the manufacturing process for the launch vehicle body, including the tank, is minimized, thereby reducing manufacturing costs and time.

[0037] Figure 1 is an exploded perspective view of a space launch vehicle body according to one embodiment of the present invention.

[0038] Figure 2 is a cross-sectional perspective view of a space launch vehicle body according to one embodiment of the present invention.

[0039] Figure 3 is a cross-sectional side view of a space launch vehicle body according to one embodiment of the present invention.

[0040] Figure 4 is a perspective projection view of a body according to one embodiment of the present invention.

[0041] Figure 5 is a front view of a body according to one embodiment of the present invention.

[0042] Figure 6 is a perspective view of a baffle according to one embodiment of the present invention.

[0043] Figure 7 is a perspective view of a boss according to one embodiment of the present invention.

[0044] Figure 8 is a cross-sectional perspective view of a boss portion according to one embodiment of the present invention.

[0045] Figure 9 is a cross-sectional perspective view of a space launch vehicle body including a fuel tank and an oxidizer tank according to one embodiment of the present invention.

[0046] Figure 10 is a cross-sectional side view of a space launch vehicle body including a fuel tank and an oxidizer tank according to one embodiment of the present invention.

[0047] Figure 11 is a flowchart showing a method for manufacturing a space launch vehicle body according to one embodiment of the present invention.

[0048] <Explanation of symbols>

[0049] 1000, 2000: Space launch vehicle fuselage

[0050] 100: Cylinder

[0051] 200: Upper dome

[0052] 300: Lower dome

[0053] 400: First Boss

[0054] 410: Dome joint

[0055] 411: Adhesive surface

[0056] 412: First bolt joint

[0057] 415: First seal groove

[0058] 420: Cap joint

[0059] 421: Second bolt joint

[0060] 425: Second seal groove

[0061] 450: Fluid flow hole

[0062] 500: Second Boss

[0063] 610: First Boss Cap

[0064] 620: Second Boss Cap

[0065] 700; Anti-vortex baffle

[0066] 800: Insulation

[0067] 900: Baffle

[0068] 910: Base

[0069] 911: First fold surface

[0070] 912: Second fold surface

[0071] 920: Side plate

[0072] 921: Mating surface

[0073] 2100: Oxidizer Tank

[0074] 2200: Fuel tank

[0075] 2300: Oxidizer transfer pipe

[0076] 2400: Workspace

[0077] 2500: Ring joint

[0078] Hereinafter, an embodiment of the present invention as described above will be described in detail with reference to the drawings.

[0079]

[0080] FIG. 1 illustrates an exploded perspective view of a space launch vehicle fuselage (1000) (hereinafter, “fuselage”) according to one embodiment of the present invention. As illustrated, the fuselage (1000) includes a cylinder (100) having a space formed therein to allow fuel to be filled and having both longitudinal sides open, an upper dome (200) sealing one open surface of the cylinder (100), a lower dome (300) sealing the other open surface of the cylinder (100), a first boss (400) coupled to the inner side of the open surface of the upper dome (200) for connection with a transfer pipe (not shown), and a second boss (500) coupled to the inner side of the open surface of the lower dome (300) for connection with the transfer pipe. In addition, a first boss cap (610) for sealing the open surface of the first boss (400) is provided on the outside of the first boss (400), and a second boss cap (620) for sealing the open surface of the second boss (500) is provided on the outside of the second boss (500). In addition, an anti-vortex baffle (700) is coupled to the inside of the second boss (500). As the fuselage (1000) consumes propellant and the water level gradually decreases, a vortex-like vortex is generated inside the fuselage (1000) at some point, and since bubbles may be sucked into the engine due to the vortex, an anti-vortex baffle (700) having a radial bulkhead structure may be provided to suppress the generation of vortices inside the fuselage (1000).

[0081] The cylinder (100) is configured as an integral body that serves as a tank in which fuel or oxidizer is filled inside and forms the outer surface of the body.

[0082] At this time, a first joint (210) for joining with the cylinder (100) is formed around the periphery of the upper dome (200), so that the first joint (210) of the upper dome (200) and one inner surface of the cylinder (100) can be joined and bonded. In addition, a second joint (310) for joining with the cylinder (100) is formed around the periphery of the lower dome (300), so that the second joint (310) of the lower dome (300) and the other inner surface of the cylinder (100) can be joined and bonded. An injection space for injecting adhesive can be formed between the cylinder and the dome, and the radial thickness of the injection space can be 2 mm or less.

[0083] At this time, the length of the first or second joint (210, 310) can be determined according to the load or internal pressure conditions required for the body (1000).

[0084] The inner diameter of the cylinder (100) is D, the internal pressure of the body (1000) is P, the length of the first or second joint (210, 310) is H, and the shear strength of the adhesive is , when the safety factor for bonding strength is defined as k, the minimum length H of the first or second joint (210, 310) can be determined through Equation 1 below.

[0085] (Formula 1)

[0086]

[0087] At this time, the actual H can be designed to have an appropriate safety factor by selecting an appropriate value of k=1.2 or higher based on the minimum H standard.

[0088]

[0089] In addition, the upper dome (200) and the lower dome (300) may be formed in the shape of an elliptical or tori-shaped dome to increase the volume efficiency of the fuselage (1000) in order to reduce the overall length of the launch vehicle fuselage (1000). At this time, the ratio of the major axis to the minor axis of the ellipse may be manufactured to have a range of 1:0.3 to 1:0.7. If it is less than the above range, a lot of stress is locally concentrated on the upper dome and the lower dome (200, 300), which may cause a problem in that the thickness must be increased to improve the composite strength, and if it is more than the above range, a problem may occur in that the length of the fuselage (1000) becomes longer in order to form the same volume.

[0090] Meanwhile, the cylinder (100), upper dome (200), and lower dome (300) may be made of fiber-reinforced composite material to reduce weight while maintaining a certain strength. For example, the cylinder (100), upper dome (200), and lower dome (300) may be made of a laminate structure formed by laminating multiple layers of composite prepreg.

[0091]

[0092] FIG. 2 illustrates a cross-sectional perspective view of a space launch vehicle body (1000) according to an embodiment of the present invention, and FIG. 3 illustrates a cross-sectional side view of a space launch vehicle body (1000) according to an embodiment of the present invention. In addition, FIG. 4 illustrates a projection perspective view of a cylinder (100) according to an embodiment of the present invention, and FIG. 5 illustrates a front view of a cylinder (100) according to an embodiment of the present invention.

[0093] As shown, the cylinder (100), upper dome (200), and lower dome (300) may be made of a fiber-reinforced composite, and an insulating material (800) for insulation may be provided on the outside of the upper dome (200).

[0094] As another example, insulation (800) may also be provided on the lower dome (300). That is, depending on the configuration of the system, insulation (800) may be attached to the upper dome (200), the lower dome (300), or both, as needed. Referring to FIG. 9, if the lower dome is located in the space between two tanks, the insulation may be omitted since no particularly temperature-sensitive devices are installed therein. However, since temperature-sensitive devices are installed at the uppermost and lowermost portions, insulation may be provided therein.

[0095] Additionally, the first and second bosses (400, 500) and the first and second boss caps (610, 620) may be made of a fiber-reinforced composite material or a metal material.

[0096] Meanwhile, a baffle (900) having a 'ㄷ' shape and an opening formed at the top may be provided on the inner surface of the cylinder (100). A plurality of baffles (900) may be spaced apart at equal intervals along the circumference of the cylinder (100) and may be spaced apart along the length direction. The baffle (900) may be provided to attenuate the operating environment of the launch vehicle and the shaking of the fluid filled inside during launch. In other words, it is provided to prevent the shaking of the fuel filled inside the fuselage (1000) and secure stability during the propulsion of the fuselage (1000). The baffle (900) may be adhesively bonded to the inner surface of the cylinder (100) using a cryogenic adhesive.)

[0097] When the baffle (900) is opened downward, the height of the bottom plate (910) that holds the water surface of the baffle (900) located at the lowest position increases accordingly. Therefore, it is preferable that the baffle (900) be opened upward and attached so that the bonding portion is located at the upper side. In addition, since a load is applied to the baffle (900) by the fluid rippling, it is structurally safer to have two bonding surfaces on the left and right sides rather than one, and since it is easier to manufacture when forming bonding surfaces on both left and right ends during manufacturing, the baffle (900) can be formed in a 'ㄷ' shape.

[0098]

[0099] Fig. 6 illustrates a perspective view of a baffle (900) according to one embodiment of the present invention. As illustrated, the baffle (900) includes a bottom plate (910) and a pair of side plates (920) extending upwardly on both sides of the bottom plate (910) in the width direction. The bottom plate (910) is formed with a first folded surface (911) that is bent downwardly on the radially outer side, and a second folded surface (912) that is bent upwardly on the radially inner side. The first and second folded surfaces (911) (912) may be formed as a reinforcing structure for increasing rigidity as the bottom plate (910) is formed thinly. The first and second folded surfaces (911) (912) may be formed by bending in directions facing each other with respect to the bottom plate (910).

[0100] The side plate (920) is formed with a joining surface (921) that is bent from the radially outer side to the circumferential inner side.

[0101]

[0102] FIG. 7 shows a perspective view of a first boss (400) or a second boss (500) according to one embodiment of the present invention, and FIG. 8 shows a cross-sectional perspective view of a first boss (400) or a second boss (500) according to one embodiment of the present invention.

[0103] Since the first boss (400) and the second boss (500) have the same shape but different joint positions, the detailed configuration of the first boss (400) will be described below.

[0104] The first and second bosses (400, 500) can be configured to form a fluid inlet / outlet of the fuselage (1000) and can be joined to the inside of the dome using adhesive, bolts, and a gas-tight seal.

[0105] More specifically, the first boss (400) can be divided into a dome joint (410) that is joined to the upper dome (200) and a cap joint (420) that is joined to the first boss cap (610) and has a fluid flow hole (450) formed therein. The first boss (400) is formed in the shape of a thick disc, and the dome joint (410) is formed on the radially outer side, and the cap joint (420) is formed on the radially inner side.

[0106] The dome joint (410) has an adhesive surface (411) formed from the radially outer end to the inner end for adhesive bonding with a dome of a certain area, and a first bolting joint (412) formed on the radially inner side of the adhesive surface (411) for bolting bonding with the dome. In addition, a first seal groove (415) into which a first seal (not shown) is inserted may be formed between the adhesive surface (411) and the first bolting joint (412). The first seal groove (415) may be formed by recessing inwardly from the outer surface of the first boss (400). The first seal may be provided to improve the sealing force between the boss and the dome.

[0107] The cap joint (420) may be formed on the radially inner side of the dome joint (410) and may be formed to protrude outward in the thickness direction. The cap joint (420) may have a second bolting joint (421) formed on the radially outer side for bolting connection with the boss cap. In addition, a second seal groove (425) into which a second seal (not shown) is inserted may be formed on the radially inner side of the second bolting joint (421). The second seal groove (425) may be formed to be recessed inward from the outer surface of the first boss (400). The second seal may be provided to improve the sealing force between the boss and the boss cap.

[0108] The first and second seals above have an inner diameter larger than the PCD of the bolt for bolting the dome and cylinder, and can be used in numbers of one to three.

[0109] When multiple seals are deployed, seals of different diameters can be arranged concentrically without overlapping. The first and second seal grooves can also be formed to match the number of seals.

[0110]

[0111] FIG. 9 shows a cross-sectional perspective view of a space launch vehicle body (2000) including a fuel tank and an oxidizer tank according to an embodiment of the present invention, and FIG. 10 shows a cross-sectional side view of a space launch vehicle body (2000) including a fuel tank and an oxidizer tank according to an embodiment of the present invention.

[0112] As illustrated, the space launch vehicle body (2000) includes an oxidizer tank (2100) containing an oxidizer and a fuel tank (2200) containing fuel. The oxidizer tank (2100) and the fuel tank (2200) may be formed of the space launch vehicle body (1000) described above.

[0113] Accordingly, the space launch vehicle body (2000) can be configured by longitudinally combining an oxidizer tank (2100) and a fuel tank (2200) manufactured using the above-described body (1000).

[0114] The oxidizer tank (2100) and the fuel tank (2200) may each be formed as one body (1000), and may be connected using a ring joint (2500) between the lower part of the oxidizer tank (2100) and the end of the upper cylinder of the fuel tank (2200).

[0115] At this time, an oxidizer transfer pipe (2300) may be provided inside the fuel tank (2200) to transfer the oxidizer of the oxidizer tank (2100) to the combustion chamber located at the lower side of the body (2000).

[0116] Additionally, a working window (2400) that allows internal inspection may be provided on the cylinder located at the connection between the oxidizer tank (2100) and the fuel tank (2200).

[0117]

[0118] FIG. 11 shows a flowchart illustrating a method for manufacturing a space launch vehicle body according to one embodiment of the present invention.

[0119] Referring to FIG. 11, a method for manufacturing a space launch vehicle body according to an embodiment of the present invention first performs a step (S11) of forming a cylinder using a fiber-reinforced composite, a step (S12) of forming an upper dome using the fiber-reinforced composite, and a step (S13) of forming a lower dome using the fiber-reinforced composite. In addition, a step (S21) of processing a baffle using a metal material, and a step (S22) of processing first and second bosses using a metal material are performed.

[0120] The above steps S11, S12, S13, S21, and S22 may be performed sequentially, in reverse order, randomly, or simultaneously.

[0121] Additionally, a step (S15) of checking whether the cylinder and dome are formed to the appropriate specifications may be further included.

[0122] Next, a step (S31) of bonding a baffle to a cylinder, a step (S32) of bonding a first boss to an upper dome, and a step (S33) of bonding a second boss to a lower dome are performed.

[0123] The above steps S31, S32, and S33 may be performed sequentially, in reverse order, randomly, or simultaneously.

[0124] Next, a step (S41) of attaching an upper dome to one side of the cylinder and a step (S42) of attaching a lower dome to the other side of the cylinder are performed.

[0125] The above steps S41 and S42 may be performed sequentially or in reverse order.

[0126] Finally, a step (S50) is performed to inspect the joint and connection status of the fuselage composed of the cylinder and dome assembly.

[0127]

[0128] The technical concept of the present invention should not be construed solely based on the aforementioned embodiments. The scope of application is diverse, and various modifications can be made by those skilled in the art without departing from the spirit of the invention as claimed in the claims. Therefore, such improvements and modifications, as long as they are obvious to those skilled in the art, fall within the scope of protection of the present invention.

Claims

1. In the body of a space launch vehicle in which a space for containing fuel or oxidizer is formed inside, A cylinder having a space formed inside to accommodate fuel or oxidizer and having both longitudinal sides open; and comprising an upper dome and a lower dome, each of which is coupled to both sides of the cylinder; An ultra-light space launch vehicle body that is constructed as an integral body that forms the outer surface of the body while also serving as a tank filled with fuel or oxidizer inside.

2. In paragraph 1, The above cylinder, upper dome and lower dome, An ultra-light space launch vehicle body made of a laminate structure made of multiple layers of fiber-reinforced composite prepreg.

3. In paragraph 1, The above upper dome and lower dome, An ultra-light space launch vehicle body inserted and joined inside the above cylinder.

4. In paragraph 1, The above upper dome and lower dome, It is adhesively bonded to the inner surface of the above cylinder, The above upper dome and lower dome, Further comprising a joint formed extending longitudinally along the radially outer circumference, An ultra-light space launch vehicle body in which the radial outer surface of the above joint is in contact with the inner surface of the cylinder and is joined through an adhesive member.

5. In paragraph 1, The above upper dome and lower dome, An ultra-light space launch vehicle body having a first open hole formed for the inflow and outflow of fuel or oxidizer, wherein a boss made of fiber-reinforced composite or metal is bonded to the first open hole.

6. In paragraph 5, An ultra-light space launch vehicle body in which a second open hole is formed in the above boss for the inflow and outflow of fuel or oxidizer, and a boss cap made of fiber-reinforced composite or metal is combined in the second open hole.

7. In paragraph 5, The above boss, An ultra-light space launch vehicle body, wherein the radial outer circumference is joined to the circumference of the first open hole, and the outer surface is joined to the inner surface of the first open hole.

8. In paragraph 4, The length (H) of the above joint is calculated using the following formula 1, which is an ultra-light space launch vehicle body.

9. In paragraph 1, The above upper dome or lower dome, It is made in the shape of an oval or torii-shaped dome, An ultra-light space launch vehicle body characterized by a major axis to minor axis ratio of 1: 0.3 to 1: 0.

7.

10. In paragraph 1, The above cylinder, A baffle is provided on the inner surface that protrudes radially inward, The above baffle is, An ultra-light space launch vehicle body in the shape of the letter 'ㄷ'.

11. In paragraph 10, The above baffle is, It includes a bottom plate and a pair of side plates extending lengthwise on both sides of the bottom plate in the width direction, The above base plate is formed with a folded surface that is folded upward or downward on the radial inner or outer side, The above side plate is an ultra-light space launch vehicle body having a joint surface formed by bending from the radially outer side to the circumferential inner side or outer side.

12. In paragraph 6, The above boss, An ultra-light space launch vehicle body comprising a dome joint formed radially outwardly and joined to the dome, and a cap joint formed radially inwardly and joined to the boss cap.

13. In paragraph 12, The above dome joint is, An adhesive surface formed for adhesive bonding with a dome of a predetermined area from the outer end in the radial direction to the inner end; A first bolting joint for bolting connection with the dome on the radially inner side of the above-mentioned bonding surface, and It includes a first seal groove formed between the above-mentioned adhesive surface and the first bolted joint, into which a seal is inserted; The above cap joint is, A second bolting joint for bolting the boss cap on the outer radial side; and An ultra-light space launch vehicle body, comprising a second seal groove into which a second seal is inserted, on the radially inner side of the second bolting joint.

14. In paragraph 1, On the outside of the upper dome, An ultra-light space launch vehicle body equipped with insulation for insulation.

15. An oxidizer tank containing an oxidizer and comprising an ultra-light space launch vehicle body of any one of the first to 14 items; A fuel tank, which is connected to the lower side of the oxidizer tank and is composed of an ultra-light space launch vehicle body of any one of the first to fourteenth clauses, and which contains fuel; and An oxidizer transfer pipe penetrating the fuel tank to transfer the oxidizer to the lower side of the fuel tank; An ultra-light space launch vehicle body, including:

16. In paragraph 15, The above ultra-light space launch vehicle body is, A ring joint provided between the lower side of the oxidizer tank and the end of the upper cylinder of the fuel tank, connecting the oxidizer tank and the fuel tank; An ultra-light space launch vehicle body that further includes:

17. In the method for manufacturing an ultra-light space launch vehicle body of any one of claims 1 to 15, A step of forming a cylinder using a fiber-reinforced composite; A step of forming a dome using a fiber-reinforced composite; A step of bonding a baffle to the above cylinder; A step of bonding a boss to the above dome; and A step of bonding the above dome to a cylinder; A method for manufacturing an ultra-light space launch vehicle body, including:

18. In paragraph 17, The step of forming a cylinder using the above fiber-reinforced composite and the step of forming a dome using the above fiber-reinforced composite or the step of bonding a baffle to the cylinder and the step of bonding a boss to the dome are, A method for manufacturing an ultra-light space launch vehicle body, which is performed sequentially, reversely or simultaneously.

19. In the method for manufacturing an ultra-light space launch vehicle body of any one of claims 1 to 14, Step 1: Forming a cylinder using a fiber-reinforced composite; A second step is to form the upper dome using a fiber-reinforced composite; The third step is to form the lower dome using a fiber-reinforced composite; Step 4: Processing a baffle using fiber-reinforced composite or metal material; Step 5 of machining a boss using a fiber-reinforced composite or metal material; A sixth step of bonding the baffle to the cylinder; Step 7 of bonding bosses to the upper and lower domes; An eighth step of bonding the upper dome to one side of the cylinder; and Step 9: Adhering the lower dome to the other side of the cylinder; A method for manufacturing an ultra-light space launch vehicle body, including:

20. In paragraph 19, The above steps 1 to 5, the above steps 6 and 7, or the above steps 8 and 9, A method for manufacturing an ultra-light space launch vehicle body, which is performed sequentially, in reverse order, randomly, or simultaneously.

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