A method of low cost construction of a space habitat

Abstract

The application provides a method for constructing a space cabin at low cost, and belongs to the technical field of space technology. The carbon fiber capsule and the thermosetting resin are packaged separately. The carbon fiber capsule can be stored at room temperature for an unlimited time, which fundamentally eliminates the problems of short service life of prepreg and dependence on cold chain. The carbon fiber capsule is packaged separately, which avoids the problems of interlayer adhesion and failure to be inflated and unfolded. The thermosetting resin is packaged separately, which prolongs the room temperature storage period and reduces the risk of resin curing failure. The application greatly reduces the construction cost of the cabin, and is beneficial to the performance of earth simulation experiments and the alternation of technology.

Description

Technical Field

[0001] This invention belongs to the field of space technology, specifically relating to a low-cost method for constructing spacecraft. Background Technology

[0002] With the development of the space industry, the demand for manned spacecraft is gradually increasing. The core challenge in building manned spacecraft on extraterrestrial bodies such as the Moon and Mars is that the interior of the spacecraft must withstand a pressure load of one atmosphere, while the exterior must have sufficient structural rigidity to withstand the threats of extreme environments. However, due to the limited launch volume of the launch vehicle, the manned spacecraft must be transported in a highly compressed state.

[0003] Existing technology has developed a "prepreg-inflation-deployment-curing" construction method. The main steps are as follows: On Earth, the cabin's skeleton (carbon fiber fabric) is pre-impregnated with thermosetting resin. During the partially cured B-stage (pre-curing to reduce tack and interlayer adhesion), the prepreg is assembled into a capsule, folded, packaged, and stored and transported under a -18°C cold chain. Upon arrival at the target location (e.g., the lunar surface), inflation unfolds the folded capsule to a predetermined shape. Heating completes the curing of the resin in the prepreg, transforming the flexible capsule into a rigid shell. This construction method has been applied or validated in some inflatable spacecraft concepts (such as NASA TransHab and Bigelow BEAM).

[0004] However, the above construction method has the following drawbacks: because the lifespan of prepreg at room temperature is short (5 to 14 days) while the transportation cycle in outer space is long, the prepreg needs to be stored in a cold chain at -18°C throughout the entire process. The cold chain equipment increases the launch mass and mission complexity. If the resin between the prepreg layers experiences temperature fluctuations during transportation, it may stick together or even solidify, causing the folded capsule to fail to inflate and unfold smoothly, rendering the entire capsule material unusable. This results in extremely high requirements for the cold chain, making the construction cost of the capsule very high. The economic threshold for conducting full-scale, full-process simulation experiments on Earth is extremely high (reaching several million yuan), which is not conducive to rapid technological iteration. Summary of the Invention

[0005] The purpose of this invention is to provide a low-cost method for constructing spacecraft. The construction method provided by this invention requires no pre-impregnation, no cold chain storage, and has low construction costs.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a low-cost method for constructing a spacecraft, comprising the following steps: The carbon fiber capsule is folded to obtain a folded envelope; the carbon fiber capsule includes a fiber skeleton and an airtight layer disposed on the inner surface of the fiber skeleton. The folded envelope and the thermosetting resin precursor are packaged separately and transported to the target work site. The folded envelope is then inflated and unfolded to obtain a molded capsule. The thermosetting resin precursor is a thermosetting resin in the prepolymer stage or an unmixed two-component resin. The thermosetting resin precursor is packaged in a sealed package. The thermosetting resin precursor is in situ impregnated on the outer surface of the molded capsule, and then cured in situ to obtain the space capsule body; the in situ impregnation method is vacuum introduction.

[0007] Preferably, when the thermosetting resin precursor is an unmixed two-component resin, the components of the two-component resin are mixed and degassed before in-situ impregnation.

[0008] Preferably, the parameters for vacuum introduction include: vacuum degree 1~10kPa, resin flow rate 5~20g / min, and resin guide mesh layer spacing not exceeding 5mm.

[0009] Preferably, the internal air pressure of the formed capsule during vacuum introduction is 10~100kPa.

[0010] Preferably, during the vacuum introduction, a slight positive pressure is applied to the storage container of the thermosetting resin, wherein the slight positive pressure is 20~30 pka.

[0011] Preferably, the method for preparing the fiber skeleton includes 3D weaving or dry fabric sewing; the parameters of the 3D weaving include: warp density 7~9 ends / cm, weft density 7~9 ends / cm, and Z-direction yarn binding density 3~5 ends / cm.

[0012] Preferably, the material of the airtight layer includes polyurea elastomer, polyurethane elastomer, or epoxy resin-based elastomer; the thickness of the airtight layer is 0.5~2mm.

[0013] Preferably, the fiber skeleton is made of carbon fiber and functional fibers; the functional fibers include glass fiber and / or aerogel fiber, and the volume ratio of carbon fiber to functional fiber is (1~4):1.

[0014] Preferably, the transport temperature is 0~40℃.

[0015] Preferably, the carbon fiber capsule further includes a functional layer disposed on the outer surface of the fiber skeleton; the functional layer includes a neutron absorbing fabric layer and a micrometeorite protective fabric layer.

[0016] This invention provides a low-cost method for constructing a space capsule, comprising the following steps: folding a carbon fiber capsule to obtain a folded envelope; the carbon fiber capsule includes a fiber skeleton and an airtight layer disposed on the inner surface of the fiber skeleton; packaging the folded envelope and a thermosetting resin precursor separately and transporting them to the target work site, then inflating and unfolding the folded envelope to obtain a shaped capsule; the thermosetting resin precursor is a thermosetting resin in the prepolymer stage or an unmixed two-component resin; the thermosetting resin precursor is packaged in a sealed package; the thermosetting resin precursor is in-situ impregnated on the outer surface of the shaped capsule, and then cured in-situ to obtain the space capsule; the in-situ impregnation method is vacuum infusion. This invention packages the carbon fiber capsule and thermosetting resin separately. The carbon fiber capsule can be stored indefinitely at room temperature, fundamentally eliminating the problems of short external lifespan and reliance on cold chains associated with prepregs. Separate packaging of the carbon fiber capsule also avoids interlayer adhesion and inability to inflate and expand. Separate packaging of the uncured A-stage thermosetting resin or unmixed two-component resin, compared to the B-stage resin in the prepreg, reduces storage requirements, extends the shelf life at room temperature, and reduces the risk of resin curing failure. This invention significantly reduces the construction cost of the capsule, facilitating Earth simulation experiments and technological advancements. Results from the embodiments show that the construction method provided by this invention results in a space capsule with a wall thickness uniformity of ±0.05 mm and no leakage after holding at an internal pressure of 0.1 MPa for 30 minutes. Attached Figure Description

[0017] Figure 1 This is a flowchart illustrating the low-cost construction of a space capsule in an embodiment of the present invention. Detailed Implementation

[0018] All raw materials used in this invention are not particularly limited in their source; they can be purchased from the market or prepared using conventional methods known to those skilled in the art.

[0019] There are no particular restrictions on the purity of any of the raw materials used in this invention, but industrially pure raw materials are preferred.

[0020] This invention provides a low-cost method for constructing a spacecraft, comprising the following steps: The carbon fiber capsule is folded to obtain a folded envelope; the carbon fiber capsule includes a fiber skeleton and an airtight layer disposed on the inner surface of the fiber skeleton. The folded envelope and the thermosetting resin precursor are packaged separately and transported to the target work site. The folded envelope is then inflated and unfolded to obtain a molded capsule. The thermosetting resin precursor is a thermosetting resin in the prepolymer stage or an unmixed two-component resin. The thermosetting resin precursor is packaged in a sealed package. The thermosetting resin precursor is in situ impregnated on the outer surface of the molded capsule, and then cured in situ to obtain the space capsule body; the in situ impregnation method is vacuum introduction.

[0021] This invention involves folding a carbon fiber capsule to obtain a folded envelope.

[0022] In this invention, the carbon fiber capsule includes an airtight layer and a fiber skeleton. The airtight layer ensures that the carbon fiber capsule can be inflated and expanded; after expansion, the fiber skeleton forms the skeleton of the capsule and, after being impregnated with resin, forms a rigid material.

[0023] In this invention, the method for preparing the fiber skeleton preferably includes 3D weaving or dry fabric sewing, more preferably 3D weaving. Both 3D weaving and dry fabric sewing are common methods for fiber weaving and forming, which are beneficial for ensuring the continuity and stability of the fiber skeleton.

[0024] In one embodiment of the present invention, the dry fabric sewing operation is as follows: the carbon fiber dry fabric (i.e., dry carbon fiber fabric without any pre-impregnation of resin) is cut into two-dimensional petals according to a predetermined shape, and the petals are sewn together using an industrial sewing machine and high-temperature resistant sewing thread to form a fiber skeleton with a predetermined geometric shape; the carbon fiber dry fabric can be T700 grade or T800 grade standard modulus carbon fiber, the weaving method is plain weave or twill weave, and the areal density is 200~400g / m². 2 The filament bundle has a specification of 3K or 6K, a thickness of 0.2~0.5mm, and a dry tensile strength of not less than 3500MPa; the high-temperature resistant sewing thread can be carbon fiber sewing thread or Kevlar fiber sewing thread; the sewing path of the high-temperature resistant sewing thread is designed along the principal stress direction after the carbon fiber capsule is inflated and expanded.

[0025] In this invention, the warp density of the 3D weaving is preferably 7~9 ends / cm, more preferably 8 ends / cm; the weft density is preferably 7~9 ends / cm, more preferably 8 ends / cm; and the Z-direction yarn density is preferably 3~5 ends / cm, more preferably 4 ends / cm. Having the 3D weaving parameters within the above ranges is beneficial for improving the strength and toughness of the fiber skeleton.

[0026] In one embodiment of the present invention, the 3D weaving can be three-dimensional orthogonal weaving or three-dimensional four-directional weaving; the areal density can be 200~400g / m³. 2 The wall thickness of the woven fabric can be 0.5~2mm.

[0027] In this invention, the fiber skeleton is preferably made of carbon fiber and functional fibers; the functional fibers preferably include glass fiber and / or aerogel fiber. Glass fiber has a higher elongation at break than carbon fiber, which can improve the damage tolerance and impact toughness of the fiber skeleton, and also reduce costs; aerogel fiber has low thermal conductivity, which can provide thermal insulation function, eliminating the need for thermal insulation felt layers and simplifying the cabin structure.

[0028] In this invention, the volume ratio of carbon fiber to functional fiber is preferably (1~4):1, more preferably (2~3):1. Using functional fiber within the above range can improve the toughness and / or thermal insulation performance of the cabin while ensuring its strength.

[0029] In one embodiment of the present invention, the carbon fiber can be T700 or T800 grade standard modulus carbon fiber with a tow specification of 3K or 6K; the glass fiber can be E glass fiber or S glass fiber; the aerogel fiber can be silica aerogel short fiber with a fiber diameter of 5~10μm, a length of 20~50mm, and a thermal conductivity of 0.015~0.02W / (m·K).

[0030] In this invention, the airtight layer is disposed on the inner surface of the fiber skeleton. The airtight layer covers the fiber skeleton, making the carbon fiber capsule form an airtight capsule, providing conditions for subsequent inflation and deployment.

[0031] In this invention, the thickness of the airtight layer is preferably 0.5~2mm, more preferably 1mm. A thickness within this range allows for weight reduction while maintaining the airtightness of the carbon fiber capsule.

[0032] In this invention, the material of the airtight layer preferably includes polyurea elastomer, polyurethane elastomer, or epoxy resin-based elastomer, and more preferably polyurea elastomer. These materials possess good airtightness and toughness, meeting the requirements for folding and inflating carbon fiber capsules.

[0033] As one embodiment of the present invention, the airtight layer can be prepared by coating the airtight coating material using an airless spraying or roller coating process, so that the coating material completely covers the stitch line and fiber pores to obtain an airtight layer; the spraying pressure of the airless spraying can be 8MPa, the coating temperature can be 70℃, and the curing time can be 24h at room temperature; the airtight coating material is a coating material obtained by mixing the precursor of the above-mentioned airtight layer material with a solvent.

[0034] In this invention, the carbon fiber capsule preferably further includes a functional layer disposed on the outer surface of the fiber skeleton; the functional layer preferably includes a neutron-absorbing fabric layer and a micrometeorite-protective fabric layer. The neutron-absorbing fabric layer can protect against secondary neutron radiation from extraterrestrial bodies; the micrometeorite-protective fabric layer can form a "buffer-fracture-shield" protective structure, improving the protective effect of the capsule.

[0035] In one embodiment of the present invention, the neutron-absorbing fabric layer can be boron-containing polyethylene nonwoven fabric or boron carbide / polyethylene composite woven fabric, with a surface density of 1.5~3 kg / m². 2 The thickness of a single layer can be 1~3mm.

[0036] In one embodiment of the present invention, the micrometeorite protective fabric layer can be a continuous ceramic fiber woven fabric or a Kevlar fabric, specifically Nextel. TM 312 or 440 type continuous ceramic fiber woven fabric or KevlarKM2; areal density can be 0.3~0.8 kg / m³. 2 The thickness of a single layer can be 0.3~0.8mm.

[0037] In one embodiment of the present invention, the functional layer can be fixed to the fiber skeleton by point stitching.

[0038] In one embodiment of the present invention, the folding can be a petal-shaped folding method, specifically: the carbon fiber capsule is flattened along the warp direction and folded sequentially towards the center, finally compressed into a cylindrical folded envelope; the compression ratio can be (20~50):1. Folding and packaging the carbon fiber capsule separately fundamentally avoids the strict requirements of cold chain storage of prepreg materials, as well as the risk of interlayer adhesion and inability to unfold the capsule.

[0039] After obtaining the folded envelope, the present invention packages the folded envelope and the thermosetting resin precursor separately and transports them to the target work site. Then, the folded envelope is inflated and unfolded to obtain a shaped capsule.

[0040] In one embodiment of the present invention, the folded and enveloping packaging material can be an aluminized polyester film dustproof transport bag.

[0041] In this invention, the thermosetting resin is either a thermosetting resin in the prepolymer stage or an unmixed two-component resin. Thermosetting resins in the prepolymer stage, where the curing reaction has not yet begun, can be stored at room temperature for a longer period, avoiding the need for a cold chain. Unmixed two-component resins, with the curing agent and resin packaged separately, can further extend the resin's shelf life. This is especially beneficial for Earth simulation experiments, allowing for on-site resin preparation. Individual packaging of thermosetting resins also improves the flexibility of resin formulation and wetting parameters, freeing them from the strict limitations of launch windows.

[0042] In this invention, the thermosetting resin is packaged in sealed packaging. Sealed packaging prevents the resin from contacting the external environment, thus extending its shelf life.

[0043] In this invention, the transportation temperature is preferably 0~40℃, more preferably 10~30℃; in an embodiment of this invention, the transportation temperature is 25℃. As one implementation of this invention, the transportation temperature can be ambient temperature. This invention eliminates the need for cold chain transportation, significantly reducing construction costs.

[0044] In one embodiment of the present invention, the thermosetting resin may be an epoxy resin, a cyanate ester resin, or a bismaleimide resin; the thermosetting resin may be stored in a lightweight flexible storage bag or a rigid container.

[0045] In one embodiment of the present invention, the inflation can be performed by first inflating to 30 kPa, holding the pressure for 5 minutes, checking whether the carbon fiber capsule is fully expanded and whether there are any wrinkles, and then continuing to inflate to the molding pressure; the inflation source can be nitrogen or air, and the inflation rate can be 0.5 kPa / s; the molding pressure can be 10~100 kPa or 30~80 kPa.

[0046] After obtaining the molded capsule, the present invention impregnates the thermosetting resin precursor on the outer surface of the molded capsule in situ, and then cures it in situ to obtain the space capsule body.

[0047] In this invention, the in-situ impregnation method is vacuum infiltration (VARTM). VARTM allows the resin to fully penetrate into the fiber skeleton, preventing the resin from remaining only on the surface of the fiber skeleton and reducing the strength of the chamber.

[0048] In this invention, the vacuum level of the vacuum introduction is preferably 1~10 kPa, more preferably 5 kPa; the resin flow rate is preferably 5~20 g / min, more preferably 10~15 g / min; and the resin guide mesh layup distance is preferably no more than 5 mm, more preferably 3 mm. VARTM parameters within the above ranges facilitate sufficient resin impregnation in the fiber skeleton, further improving the strength and toughness of the chamber.

[0049] In this invention, when the thermosetting resin is an unmixed two-component resin, it is preferable to mix the resin components and then degas them before in-situ impregnation. As one embodiment of this invention, the mixing can be mechanical stirring for 5 minutes; the degassing can be degassing in a vacuum degassing tank for 15 minutes; the vacuum degree of the vacuum degassing tank can be 1 kPa.

[0050] As one embodiment of the present invention, the viscosity of a thermosetting resin can be reduced by heating, wherein the heating temperature is lower than the curing temperature of the thermosetting resin.

[0051] In one embodiment of the present invention, the vacuum introduction operation can be as follows: a release cloth, a flow guide net, and a glue injection port are sequentially laid on the outer surface of the molded capsule, and then a vacuum bag film is covered; the edge of the vacuum bag film is fixed to the bottom of the molded capsule with a vacuum-resistant sealing strip, and a rigid flange is provided as an air extraction port; the release cloth can be polytetrafluoroethylene coated fiberglass cloth; the flow guide net can be made of polypropylene with a thickness of 3mm; the glue injection port is located at the top of the molded capsule; the vacuum bag film can be a polyimide film; Then connect the suction port to the vacuum pump to evacuate the vacuum bag film; connect the container containing resin to the glue injection port to impregnate it with resin; when resin flows out of the suction port, close the glue injection port and maintain the vacuum for 10 minutes to remove excess resin and air bubbles.

[0052] In one embodiment of the present invention, the vacuum-introducing auxiliary components can be deployed on Earth and, after being inflated and deployed in outer space, directly connected to a vacuum pump and resin for in-situ impregnation. This simplifies space operations, further reduces operational difficulty, and improves construction stability. Compared to existing technologies, the present invention pre-defines the vacuum-introducing components on Earth, and during space operations, only adds the connection between the evacuation port and the vacuum pump, and the connection between the injection port and the resin storage container. This operation is similar to the connection between the carbon fiber capsule and the inflation device, enabling space operations.

[0053] In this invention, during vacuum introduction, a slight positive pressure is preferably applied to the storage container of the thermosetting resin, preferably 20-30 pka. Applying a slight positive pressure to the storage container of the thermosetting resin facilitates resin outflow from the container and improves the efficiency of in-situ wetting.

[0054] In this invention, the internal air pressure of the molded capsule during vacuum introduction is preferably 10~100 kPa, more preferably 30~80 kPa; as one embodiment of this invention, the internal air pressure of the molded capsule during vacuum introduction can be 30 kPa, 40 kPa, 50 kPa, 60 kPa, 70 kPa, or 80 kPa. Maintaining a certain air pressure in the molded capsule can serve as a flexible template for resin impregnation, maintaining the precise geometry of the capsule; an internal air pressure within the above range is beneficial for in-situ impregnation.

[0055] In one embodiment of the present invention, the temperature of the gas inside the molded capsule during in-situ immersion can be 15~40°C; the temperature can be controlled by heating the gas inside the molded capsule.

[0056] In one embodiment of the present invention, the in-situ curing can be achieved by continuously blowing hot air into the molded capsule to reach the curing temperature of the thermosetting resin, and holding at that temperature for 60-120 minutes; the hot air can be hot air or hot nitrogen. After in-situ curing is completed, the capsule is allowed to cool naturally, and the capsule construction is complete.

[0057] In an embodiment of the present invention, the flowchart for the low-cost construction of the spacecraft is as follows: Figure 1 As shown, the steps are as follows: cutting and sewing carbon fiber dry cloth petals to form a capsule; stacking functional layers and installing embedded parts; folding and packaging the petals; inflating and unfolding the capsule to the designed shape on the lunar surface; keeping the capsule inflated and impregnating it with liquid resin in situ; curing it in situ to transform it into a rigid shell.

[0058] This invention packages the carbon fiber capsule and thermosetting resin separately. The carbon fiber capsule can be stored indefinitely at room temperature, fundamentally eliminating the problems of short lifespan and reliance on cold chains associated with prepregs. Separate packaging of the carbon fiber capsule also avoids problems such as interlayer adhesion and inability to inflate and expand. Separate packaging of the uncured A-stage thermosetting resin or unmixed two-component resin, compared to the B-stage resin in the prepreg, reduces storage requirements, extends the shelf life at room temperature, and reduces the risk of resin curing failure. This invention significantly reduces the construction cost of the capsule, which is beneficial for conducting Earth simulation experiments and technological advancements.

[0059] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0060] Example 1 A low-cost method for constructing a spacecraft, comprising the following steps: Cabin design specifications Shape: Sphere, designed diameter 2.0m, internal volume approximately 4.2m³ when unfolded. 3 ; Design pressure resistance: internal pressure 90 kPa (relative to lunar vacuum). Target structural layer thickness: The cured carbon fiber composite layer thickness is 1.0 mm ± 0.1 mm; Materials list: The carbon fiber dry cloth is made of T700 grade, plain weave, with an areal density of 300g / m². 2 The filament bundle is 3K, with a thickness of 0.33mm and a width of 1.5m. Polyurea elastomer coating (two-component); boron-containing polyethylene nonwoven fabric, areal density 2.0 kg / m³ 2 , 2mm thick; NextelTM 312 fabric, with an areal density of 0.5 kg / m² 2 Thickness 0.5mm; The thermosetting resin system uses low-viscosity bisphenol A type epoxy resin EPON862, combined with aliphatic amine curing agent D230, with a viscosity of 150 mPa·s (25℃) after mixing; The charging gas is high-purity nitrogen (99.99%), used for expansion and pressure holding; Portable vacuum pump (suitable for 10... -5 (Pa background vacuum); Manufacturing steps Step (a): 3D weaving of capsules (completed on Earth) A three-dimensional four-way weaving machine (model: 3DWeavingMachineQX-8) was used, employing T700 grade carbon fiber (3K tow) as the main weaving yarn. The weaving parameters were: warp density 8 ends / cm, weft density 8 ends / cm, Z-axis binding density 4 ends / cm, and weave wall thickness 1.0 mm. The capsule shape was a sphere with a diameter of 2.0 m, using near-net-shape weaving. During the weaving process, silica aerogel short fibers (volume ratio of carbon fiber:aerogel fiber = 4:1) were mixed into the carbon fiber bundles to ensure uniform distribution of aerogel fibers in the weave. The finished capsule weighed 11.31 kg and had a wall thickness of 1.0 mm ± 0.05 mm. Step (b): Functional layer stacking and installation of embedded parts (ground completion) The following layers were laid sequentially on the outside of the capsule: a neutron absorption layer (fixed to the capsule by spot stitching), and two layers of Nextel fabric (cross-laid and fixed by stitching); a polyurea coating was sprayed onto the inner surface of the capsule: using a GracoReactor E-10 two-component sprayer, spraying pressure 8MPa, coating temperature 70℃, and dry film thickness 1.0mm; after spraying, it was cured at room temperature for 24 hours. Step (c): Lobe-shaped folding and packaging (Earth completes) The above-mentioned multi-layer carbon fiber capsules are folded using a petal-like folding method: the capsules are flattened along the warp direction and folded sequentially towards the center, ultimately compressed into a cylindrical folded envelope with a diameter of 0.4m and a height of 0.3m, with a compression ratio of 45:1; they are then placed in dustproof transport bags (made of aluminized polyester film) and stored at room temperature; EPON862 resin and curing agent D230 are separately sealed in airtight containers and stored at room temperature (shelf life is 1 year). Step (d): Simulated lunar surface inflation and deployment (conducted inside a hot vacuum chamber) The folded envelope was placed in a heated vacuum chamber and evacuated to a vacuum level of 1.3 × 10⁻⁶. -4Pa (simulating lunar vacuum), background temperature -20℃; nitrogen gas is injected into the folded envelope at a rate of 0.5 kPa / s through the inflation line until the internal pressure reaches 30 kPa. This pressure is maintained for 5 minutes, and the capsule is checked to be fully expanded and without wrinkles; then the pressure is increased to 80 kPa as the forming pressure. Step (e): In-situ resin impregnation (VARTM method, performed in a vacuum chamber) (e1) VARTM system layout Under the condition of inflation and expansion while maintaining an internal air pressure of 50 kPa, the following are laid sequentially on the outer surface of the molded capsule: release cloth (PTFE-coated fiberglass cloth), flow guide net (polypropylene, 3 mm thick, 3 mm mesh spacing), and injection port (at the top of the molded capsule), and then covered with vacuum bag film (polyimide film); the edge of the vacuum bag film is fixed to the bottom of the molded capsule with vacuum-resistant sealing strip, and a rigid flange is set as an air extraction port for connecting a vacuum pump; (e2) Vacuum suction Start the vacuum pump to evacuate the inside of the vacuum bag membrane, reducing the absolute pressure inside the vacuum bag to 5 kPa. At this time, the pressure inside the formed capsule is 50 kPa, so the pressure difference between the inside and outside of the formed capsule is 45 kPa. This pressure difference keeps the formed capsule in an expanded state, while the vacuum bag membrane is tightly attached to the outside of the functional layer, forming a closed ring cavity. Continue evacuating for 10 minutes and check the vacuum bag membrane for leaks. (e3) Resin mixing and degassing Mix EPON862 and D230 at a mass ratio of 100:32, stir mechanically for 5 minutes, and then let stand for 1 minute for later use; the viscosity of the degassed resin is 120 mPa·s (heated to 25°C). (e4) Resin introduction The degassed resin is connected to the injection port inside the vacuum bag membrane through the injection tube. The resin is driven to flow into the vacuum bag membrane by the pressure difference between the absolute pressure of 5 kPa inside the vacuum bag membrane and the slight positive pressure of 20 kPa applied inside the resin container. The total amount of resin used is 7.54 kg. During the actual impregnation process, the resin front is evenly advanced in the guide net and flows from the injection port to the air extraction port. When resin flows out of the air extraction port, the injection port is closed and the vacuum suction is maintained for 10 minutes to remove excess resin and air bubbles. Step (f): In-situ curing Hot nitrogen gas (130℃) was blown into the capsule to raise the temperature of the inner surface of the capsule to 120℃±5℃ and kept at that temperature for 90 minutes. Heating was stopped and the capsule was allowed to cool naturally to room temperature (2 hours, background temperature of -20℃). The gas was released to normal pressure (atmospheric pressure inside the vacuum chamber), and the capsule was removed to obtain the space capsule body.

[0061] Construction results After curing, the chamber is a rigid thin-shell sphere with a measured thickness of 0.95~1.05mm, without delamination or bubbles (visual inspection); it can be pressured for 30 minutes at an internal air pressure of 0.1MPa without leakage.

[0062] Example 2 A low-cost method for constructing a spacecraft, comprising the following steps: Cabin design specifications Shape: Cylindrical with hemispherical end caps, total length 3.0m, diameter 1.5m, volume approximately 5.3m³. 3 ; Design pressure resistance: Internal air pressure 120kPa (simulating ground positive pressure); Target structural layer thickness: 1.2mm; Materials list The carbon fiber dry cloth is made of T800 grade, twill weave (2 / 2), with an areal density of 400g / m². 2 The filament bundle is 6K and the thickness is 0.45mm. The sewing thread used is Kevlar 49 sewing thread with a linear density of 400 tex and a usage of approximately 300m; the airtight layer is aliphatic polyurethane elastomer with a thickness of 1.2mm; the outer protective layer is a single layer of Kevlar KM2 fabric (thickness 0.6mm); the heat insulation layer is a multi-layer heat insulation felt (10 layers) of aluminized polyimide (MLI) with a total thickness of 8mm; the resin system uses bismaleimide (BMI) resin (brand: Cytec 5250-4, stored in a sealed container below 25℃ away from light, shelf life 12 months), with a viscosity of 300mPa·s (120℃); the filling gas is compressed air; the curing equipment includes an industrial hot air blower (outlet temperature adjustable to 250℃) and a thermocouple temperature control device; Manufacturing steps Step (a): Dry cloth sewing to form a sac Cut the T800 dry cloth into: two rectangular pieces of cloth for the cylindrical part (3.0m×1.5m in size), and six pieces for each end cap; use Kevlar sewing thread to sew along the main stress direction with a stitch spacing of 5mm, allowing for a certain degree of elastic deformation of the sewing thread; Step (b): Functional layer overlay Spray polyurethane elastomer (1.2 mm thick, cured at room temperature for 24 hours) onto the inner surface; then stitch and fix the Kevlar protective layer and MLI insulation layer onto the outer surface in sequence. Step (c): Lobe-like folding Folded into a 0.5m×0.4m×0.5m fold envelope in a manner similar to Example 1, with a compression ratio of 25:1; Step (d): Inflate and deploy In a ground-based factory (at normal temperature and pressure), compressed air is introduced at a rate of 0.3 kPa / s to 100 kPa, and the pressure is maintained for 10 minutes to fully expand, thus obtaining a shaped capsule. Step (e): In-situ resin impregnation BMI resin is preheated to 120℃ to reduce viscosity. Under conditions of inflation and expansion while maintaining an internal pressure of 50 kPa within the molded capsule, the following are sequentially laid on the outer surface of the capsule: release cloth (PTFE-coated fiberglass cloth), flow guide mesh (polypropylene, 3 mm thick, 3 mm mesh spacing), and injection port (top of the vacuum capsule). Then, a vacuum bag film (polyimide film) is placed over it. The edges of the vacuum bag film are fixed to the bottom of the molded capsule with vacuum-resistant sealing strips, and a rigid flange is provided as an extraction port for connecting a vacuum pump. Vacuum is evacuated to an absolute pressure of 2 kPa; the resin flow rate is controlled at 15 g / min. Step (f): Heating and curing in situ Hot air (inlet temperature 250℃) was blown into the chamber to raise the temperature of the composite material layer to 200±5℃, and the temperature was maintained for 120 minutes before naturally cooling to room temperature.

[0063] Construction results The cabin wall thickness is uniform (1.15~1.25mm), and no leakage was found after a water pressure test (120kPa, 2h); the total cost of ground verification is approximately RMB 80,000.

[0064] Comparative Example 1 Using the same geometric dimensions (2.0m diameter sphere) and the same carbon fiber fabric (T700, 300g / m²) as in Example 1. 2 It uses the same epoxy resin system, but is constructed according to the existing prepreg-air-expansion-curing route; The specific implementation of the prepreg route is as follows: On Earth, T700 dry cloth is impregnated with EPON862 / D230 resin and pre-cured at 130°C for 10 minutes to produce a prepreg with a resin content of 33% (the same as the final product in Example 1); the prepreg is stored at -18°C with a nominal external lifespan of 12 days; the prepreg is cut and sewn into identical capsules (the resin is already present during sewing, and the needles are easy to adhere); after folding, it is transported to a thermal vacuum chamber (simulating the lunar surface) in a dry ice insulated box; the transportation takes 7 days; the thermal vacuum chamber is inflated and deployed (pressure 80 kPa); it is then heated and cured (under the same conditions as in Example 1) to obtain the space capsule body.

[0065] Main problems encountered On the 10th day of transport, the temperature of the insulated box briefly rose to -5℃ (about 6 hours), and local adhesion appeared on the surface of the prepreg, making it impossible to completely separate the folded layers. When inflated and unfolded, the adhesion area prevented the capsule from fully unfolding, forming an unexpanded fold with a diameter of 15cm. After heating and curing, fibers accumulated and resin enriched at the fold, resulting in uneven wall thickness (up to 2.5mm in some areas) and microcracks. The capsule experienced local bulging and leakage under an internal air pressure of 60kPa.

[0066] Summary of comparison results Regarding storage / transportation conditions, Embodiment 1 of this invention operates at room temperature with no time limit (relatively long), while the prepreg route involves a -18°C cold chain for no more than 12 days. Regarding transportation risks, this invention is risk-free, while the prepreg route carries the risk of adhesion due to temperature fluctuations. Regarding unfolding integrity, this invention achieves 100% complete unfolding, while the prepreg route exhibits wrinkles and un-unfolded areas. Regarding wall thickness uniformity after curing, this invention performs well (±0.05mm), while the prepreg route performs poorly (local deviations exceeding 1mm). Regarding pressure resistance (passing the 90kPa test), this invention passes the test, while the prepreg route fails (leaking occurs at 60kPa). Regarding the cost of full-scale ground verification, the technical solution of this invention costs 60,000 to 80,000 RMB, while the prepreg route costs approximately 3 million RMB (including cold chain and special prepreg storage).

[0067] As can be seen from the above embodiments and comparative examples, the method provided by the present invention is significantly superior to existing prepreg routes in terms of room temperature storage and transportation, deployment reliability, final structural integrity and economy.

[0068] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A low-cost method for constructing a spacecraft, comprising the following steps: The carbon fiber capsule is folded to obtain a folded envelope; the carbon fiber capsule includes a fiber skeleton and an airtight layer disposed on the inner surface of the fiber skeleton. The folded envelope and the thermosetting resin precursor are packaged separately and transported to the target work site. The folded envelope is then inflated and unfolded to obtain a molded capsule. The thermosetting resin precursor is a thermosetting resin in the prepolymer stage or an unmixed two-component resin. The thermosetting resin precursor is packaged in a sealed package. The thermosetting resin precursor is in situ impregnated on the outer surface of the molded capsule, and then cured in situ to obtain the space capsule body; the in situ impregnation method is vacuum introduction.

2. The method according to claim 1, characterized in that, When the thermosetting resin precursor is an unmixed two-component resin, the components of the two-component resin are mixed and degassed before in-situ impregnation.

3. The method according to claim 1, characterized in that, The parameters for vacuum introduction include: vacuum degree 1~10kPa, resin flow rate 5~20g / min, and resin guide mesh layer spacing not exceeding 5mm.

4. The method according to claim 3, characterized in that, The internal air pressure of the formed capsule during vacuum introduction is 10~100kPa.

5. The method according to claim 3, characterized in that, During the vacuum introduction, a slight positive pressure of 20~30 pka is applied to the storage container of the thermosetting resin.

6. The method according to claim 1, characterized in that, The fiber skeleton is prepared by 3D weaving or dry fabric sewing; the parameters of the 3D weaving include: warp density 7~9 ends / cm, weft density 7~9 ends / cm, and Z-direction binding yarn density 3~5 ends / cm.

7. The method according to claim 1, characterized in that, The material of the airtight layer includes polyurea elastomer, polyurethane elastomer, or epoxy resin-based elastomer; the thickness of the airtight layer is 0.5~2mm.

8. The method according to claim 1, characterized in that, The fiber skeleton is made of carbon fiber and functional fibers; the functional fibers include glass fiber and / or aerogel fiber, and the volume ratio of carbon fiber to functional fiber is (1~4):

1.

9. The method according to claim 1, characterized in that, The transport temperature is 0~40℃.

10. The method according to any one of claims 1 to 9, characterized in that, The carbon fiber capsule also includes a functional layer disposed on the outer surface of the fiber skeleton; the functional layer includes a neutron absorbing fabric layer and a micrometeorite protective fabric layer.

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