Low-orbit large spacecraft aluminum alloy framework autonomous disintegration system and control method

Abstract

The invention discloses a low-orbit large spacecraft aluminum alloy framework autonomous disintegration system and a control method. The low-orbit large spacecraft aluminum alloy framework autonomous disintegration system comprises an aluminum alloy framework, an activation signal unit and a liquid metal triggering unit. The activation signal unit is used for receiving an external signal and sending an activation signal to the liquid metal triggering unit; the liquid metal triggering unit comprises liquid metal, a storage bin for sealing the liquid metal and a protective gate; the protective gate is arranged between the liquid metal and the aluminum alloy framework so as to isolate the liquid metal from the aluminum alloy framework; the protection gate receives the activation signal and releases the liquid metal, so that the liquid metal makes contact with the aluminum alloy framework and diffuses and permeates into the aluminum alloy framework along the grain boundary of the aluminum alloy, the structural integrity is destroyed, the spacecraft is decomposed, the orbit is lowered under the influence of residual atmosphere and the like, and finally the spacecraft enters the atmosphere to be completely burnt out. Compared with the prior art, the device can be controllably disassembled, and space junk is avoided.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of spacecraft, in particular to a low-orbit large spacecraft aluminum alloy framework autonomous disintegration system and control method. BACKGROUND

[0002] Space junk, also known as space debris, refers to the debris of various man-made objects in operation in the Earth's orbit, such as abandoned satellites, rocket debris, and collision debris. With the increasing frequency of human exploration of outer space, the amount of space junk has increased dramatically. There are currently more than 100,000 pieces of space junk in the Earth's orbit. These space junk moves at a very high speed, up to 29,000 kilometers per hour, and a collision with any satellite or spacecraft in operation can cause significant damage, even threatening the safety of astronauts. Space junk has seriously affected human space activities. For example, in 2016, a few micrometer-diameter metal debris hit the window of the International Space Station, creating a 7mm-diameter hole. In 2021, the Canadian robotic arm-2 of the International Space Station was hit by a piece of debris that was not within the monitoring range, causing a nearly 10mm-diameter hole. In 2022, a 0.8mm-diameter hole in the outer shell of the Russian Soyuz spacecraft caused a 44kg coolant leak. Therefore, the management of space junk has become an urgent practical problem to be solved.

[0003] Currently, the management of space junk mainly relies on four strategies: avoidance, prevention, protection, and cleanup. In terms of prevention, the measures usually taken include active de-orbiting at the end of the satellite's life, i.e., using the remaining propellant to lower the orbit and make it burn up in the atmosphere; for geosynchronous orbit satellites, they are transferred to a special "graveyard orbit". Small low-orbit spacecraft will gradually decay in orbit and re-enter the atmosphere for destruction due to the influence of residual atmospheric resistance; large spacecraft, due to the difficulty of complete burning, need to be controlled to fall into the designated uninhabited area to avoid damage to ground personnel and facilities. However, there is still a risk of uncontrolled falling of large spacecraft. Historical events have highlighted this risk: in the 1970s and 1980s, a Soviet nuclear-powered satellite fell uncontrollably into Canada, causing nuclear pollution concerns; the debris of the American Space Laboratory also scattered into residential areas; in 2021, the International Space Station discarded a 2-ton battery tray component that did not completely burn, penetrating the roof of a two-story residential building in Spain. These cases all show that the re-entry process of an uncontrolled large spacecraft has significant social and safety risks. There is still a lack of experience in dealing with large spacecraft that have lost control in low orbit, and existing solutions all have significant risks and drawbacks. For example, using a large transport vehicle to recover in orbit is costly; using anti-satellite weapons to smash large spacecraft will add new space junk; the accuracy, timeliness, and rapid evacuation capability of tracking the falling area and evacuating personnel cannot be effectively guaranteed.

[0004] Therefore, in view of the above problems, there is a need to improve the structure of the existing spacecraft. SUMMARY

[0005] The first technical problem to be solved by the present application is to provide a low-orbit large spacecraft aluminum alloy framework autonomous disintegration system capable of controllable disintegration and avoiding space debris.

[0006] The second technical problem to be solved by the present application is to provide a control method for the low-orbit large spacecraft aluminum alloy framework autonomous disintegration system.

[0007] The technical solution adopted by the present application to solve the above first technical problem is a low-orbit large spacecraft aluminum alloy framework autonomous disintegration system, comprising an aluminum alloy framework, characterized in that it further comprises an activation signal unit and a liquid metal triggering unit. The activation signal unit is used to receive external signals and send activation signals to the liquid metal triggering unit. The liquid metal triggering unit comprises a storage bin for storing liquid metal and a protective gate; the protective gate is arranged between the liquid metal and the aluminum alloy framework to isolate the liquid metal and the aluminum alloy framework. The protective gate receives the activation signal and releases the liquid metal, so that the liquid metal contacts the aluminum alloy framework and penetrates into the aluminum alloy framework along the grain boundary of the aluminum alloy.

[0008] Preferably, the liquid metal is a Ga-In-Sn alloy, which comprises the following components by weight: 10-20wt.% Ga, 20-30wt.% In and 50-70wt.% Sn; the liquid metal is a film or metal sheet with a thickness of 0.5-1mm.

[0009] The lower limit of the critical concentration of Ga in the liquid metal is 10wt.%, which can ensure that after the spacecraft is scrapped, the liquid metal can effectively penetrate the grain boundary of the aluminum alloy to form a continuous brittle layer, so that the aluminum alloy framework is brittle and broken; and the upper limit of 20wt.% avoids the liquid metal from expanding rapidly due to too high Ga content, causing the structure of the pre-embedded liquid metal triggering unit to break, causing the liquid metal to seep out and damage the aluminum alloy framework of the spacecraft during normal operation.

[0010] The main role of In in the liquid metal is to adjust the melting point of the liquid metal alloy. If the content of In in the liquid metal is less than 20wt.%, the melting point of the liquid metal is lower than 60℃, which cannot guarantee the stability of the liquid metal during on-orbit storage; if the content of In exceeds 30wt.%, an Al-rich phase will be formed on the surface of the aluminum alloy, thereby greatly reducing the brittle rate of the liquid metal.

[0011] The main function of Sn in liquid metal is to provide sufficient mechanical support when the liquid metal is not activated. If the Sn content in the liquid metal is less than 50 wt.%, the liquid metal will not have enough mechanical strength to withstand the vibration load during spacecraft launch and operation when the liquid metal trigger unit is not activated, and will break. If the Sn content exceeds 70 wt.%, the flow properties of the liquid metal will decrease, so that the liquid metal cannot be uniformly covered on the surface of the aluminum alloy skeleton in the activated state, thus reducing the disintegration speed of the aluminum alloy skeleton.

[0012] The thickness of the liquid metal is 0.5-1mm. When the thickness is less than 0.5mm, the rate at which the liquid metal embrittles the aluminum alloy skeleton is too slow to meet the embrittlement rate requirements. When the thickness exceeds 1mm, the liquid metal is prone to falling off the surface of the protective gate, resulting in the failure of liquid metal release when the protective gate is opened.

[0013] Preferably, the activation signal unit includes a spacecraft receiver for receiving ground signals and a Peltier element electrically connected to the spacecraft receiver to emit a thermal signal. The Peltier element is heated to 180-200°C to emit a thermal signal.

[0014] Preferably, the protective gate is a shape memory metal Au-Pd alloy; the phase transformation temperature of the Au-Pd alloy is 170-180℃.

[0015] Preferably, the storage chamber is disposed on the surface of an aluminum alloy frame; the thickness of the storage chamber is 40-100 μm, and the storage chamber is made of a shape memory polymer, specifically polyimide. If the thickness of the storage chamber is less than 40 μm, it cannot withstand the temperature fluctuations of space (-150℃-200℃) and space radiation, leading to the decomposition and release of the internal liquid metal; if the thickness of the storage chamber is greater than 100 μm, the flexibility of the storage chamber decreases significantly, making it prone to cracking.

[0016] The technical solution adopted by this invention to solve the second technical problem mentioned above is: a control method for an autonomous disintegration system of an aluminum alloy skeleton for a large low-orbit spacecraft, characterized by comprising the following steps: ① Receiving ground signals: After the activated signal unit receives the signal sent by the ground control center, it heats up to 180-200℃ and emits a heat signal; ② Protective gate opening: The thermal signal of the activation signal unit causes the protective gate to undergo a shape memory effect through heat conduction, resulting in multiple liquid metal release channels formed by the protective gate; ③ Liquid metal release and diffusion: The liquid metal melts into a liquid state due to the heating effect of the thermal signal of the activation signal unit. Under capillary action, it contacts the aluminum alloy skeleton along the liquid metal release channel, and then diffuses and penetrates into the aluminum alloy skeleton along the grain boundary of the aluminum alloy. ④ Spacecraft disintegration: Under vibration load, the aluminum alloy skeleton fractures and decomposes along the embrittled region where liquid metal has penetrated, causing the aluminum alloy skeleton to form small fragments; the small fragments are affected by the residual atmospheric drag in low orbit, continuously decreasing the orbital altitude, and are burned up upon re-entry into the atmosphere.

[0017] Preferably, step ① is as follows: after the spacecraft receiver receives the signal sent by the ground control center, the spacecraft receiver sends a signal to activate the Peltier element, causing the Peltier element to heat up to 180-200°C.

[0018] Spacecraft need to withstand temperatures ranging from -100℃ to 150℃ when operating in outer space. Setting the heating temperature of Peltier components to 180℃-200℃ can effectively prevent the device from being accidentally triggered due to temperature fluctuations in outer space, thereby ensuring the realization of controllable embrittlement, while avoiding the high power consumption caused by excessively high heating temperatures.

[0019] Preferably, the spacecraft receiver receives signals transmitted by the ground control center via radio.

[0020] Compared with existing technologies, the advantages of this invention are as follows: Under normal conditions, the liquid metal is isolated from the aluminum alloy frame by a protective gate and sealed in the storage chamber. When a release signal is received from the outside, the signal unit is activated to emit a signal, causing the shape of the protective gate to change, allowing the liquid metal to come into contact with the spacecraft's aluminum alloy frame. This allows it to diffuse along the grain boundaries of the aluminum alloy, destroying the intergranular strength and causing the aluminum alloy to become brittle and decompose. This further enables the spacecraft to break down into small fragments. These small fragments are subject to the drag of the residual atmosphere in low orbit, continuously decreasing their orbital altitude, and then burning up upon re-entry into the atmosphere. This reduces space debris at its source, effectively reducing the risks posed by space debris, and is both economical and feasible. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the autonomous disintegration system in Example 1; Figure 2 This is a schematic diagram of the shape memory effect of the protective gate in Example 1; Figure 3 High-magnification morphology image and EDS analysis diagram of the longitudinal section of the aluminum alloy skeleton. Detailed Implementation

[0022] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Example 1

[0023] An autonomous dismantling system for a large low-orbit spacecraft aluminum alloy frame 1, comprising an aluminum alloy frame 1, characterized in that: it further comprises an activation signal unit and a liquid metal trigger unit; the activation signal unit comprises a spacecraft receiver for receiving ground signals and a Peltier element 2 electrically connected to the spacecraft receiver; the spacecraft receiver receives signals sent by the ground control center via radio.

[0024] The liquid metal triggering unit includes liquid metal 5, a protective gate 3, and a storage chamber 4. Liquid metal 5 is a Ga-In-Sn alloy with a melting point of 62°C and comprises the following components by weight: 15 wt.% Ga, 24 wt.% In, and 61 wt.% Sn. Liquid metal 5 is attached to the surface of the protective gate 3 by electroplating, with a thickness of 0.7 mm.

[0025] The protective gate 3 is a shape memory metal Au-Pd alloy, and is located between the liquid metal 5 and the aluminum alloy frame 1 to isolate the liquid metal 5 and the aluminum alloy frame 1; the protective gate 3 is fixed to the surface of the aluminum alloy frame 1 by a low temperature brazing process; the phase transformation temperature of the Au-Pd alloy is 175℃.

[0026] Storage chamber 4 is disposed on the surface of liquid metal 5 to seal liquid metal 5; storage chamber 4 has a thickness of 60μm; and storage chamber 4 is a shape memory polymer polyimide.

[0027] The control method for the autonomous disintegration system of the aluminum alloy frame 1 of the aforementioned large low-orbit spacecraft includes the following steps: ① Receiving ground signals: After the spacecraft completes its service life, the ground control center sends a signal to the spacecraft receiver. The spacecraft receiver sends a signal to activate Peltier element 2, causing Peltier element 2 to heat up to 180°C. ② The protective gate 3 opens: The Peltier element 2 causes the protective gate 3 to undergo a shape memory effect through heat conduction, so that the protective gate 3 forms a liquid metal release channel 31; ③ Release and diffusion of liquid metal 5: Liquid metal 5 melts into a liquid state due to the heating effect of Peltier element 2. Under capillary action, it contacts the aluminum alloy skeleton 1 along the liquid metal release channel 31, and then diffuses and penetrates into the aluminum alloy skeleton 1 along the grain boundaries. After 48 hours, the changes in tensile strength of the aluminum alloy before and after the action of liquid metal 5 are shown in Table 1. As can be seen from Table 1, the tensile strength of the aluminum alloy decreased by more than 20% due to crack propagation induced by local stress concentration. Figure 3 These are high-magnification morphology images and EDS analysis diagrams of the longitudinal section of the aluminum alloy skeleton 1; from Figure 3 It can be seen that Ga is enriched at the grain boundaries of aluminum alloys, which weakens the grain boundary strength and causes grain boundary cracking.

[0028] ④ Spacecraft disintegration: Under vibration load, the aluminum alloy skeleton 1 fractures and decomposes along the embrittled region where the liquid metal 5 has penetrated, causing the aluminum alloy skeleton 1 to form small fragments; the small fragments are affected by the residual atmospheric drag in the low orbit, continuously decrease in orbital altitude, and are burned up upon re-entry into the atmosphere. Example 2

[0029] An autonomous dismantling system for a large low-orbit spacecraft aluminum alloy frame 1, comprising an aluminum alloy frame 1, characterized in that: it further comprises an activation signal unit and a liquid metal trigger unit; the activation signal unit comprises a spacecraft receiver for receiving ground signals and a Peltier element 2 electrically connected to the spacecraft receiver; the spacecraft receiver receives signals sent by the ground control center via radio.

[0030] The liquid metal triggering unit includes liquid metal 5, a protective gate 3, and a storage chamber 4. Liquid metal 5 is a Ga-In-Sn alloy, comprising the following components by weight: 17 wt.% Ga, 25 wt.% In, and 58 wt.% Sn; its melting point is 64°C. The protective gate 3 is a shape memory metal Au-Pd alloy, disposed between the liquid metal 5 and the aluminum alloy skeleton 1, isolating the liquid metal 5 from the aluminum alloy skeleton 1; the phase transition temperature of the Au-Pd alloy is 175°C. The storage chamber 4 is disposed on the surface of the liquid metal 5 to seal the liquid metal 5; the storage chamber 4 has a thickness of 70 μm and is made of shape memory polymer polyimide. Liquid metal 5 is a 0.9 mm thick film, attached to the surface of the protective gate 3 by chemical plating.

[0031] The control method for the autonomous disintegration system of the aluminum alloy frame 1 of the aforementioned large low-orbit spacecraft includes the following steps: ① Receiving ground signals: After the spacecraft completes its service life, the ground control center sends a signal to the spacecraft receiver. The spacecraft receiver sends a signal to activate Peltier element 2, causing Peltier element 2 to heat up to 183°C. ② The protective gate 3 opens: The Peltier element 2 causes the protective gate 3 to undergo a shape memory effect through heat conduction, so that the protective gate 3 forms a liquid metal release channel 31; ③ Release and diffusion of liquid metal 5: Liquid metal 5 melts into a liquid state due to the heating effect of Peltier element 2. Under capillary action, it contacts aluminum alloy skeleton 1 along liquid metal release channel 31, and then diffuses and penetrates into aluminum alloy skeleton 1 along the grain boundary of aluminum alloy. After 48 hours, the change in tensile strength of aluminum alloy before and after the action of liquid metal 5 is shown in Table 1. The tensile strength of aluminum alloy decreased from 462 MPa to 305 MPa.

[0032] ④ Spacecraft disintegration: Under vibration load, the aluminum alloy skeleton 1 fractures and decomposes along the embrittled region where the liquid metal 5 has penetrated, causing the aluminum alloy skeleton 1 to form small fragments; the small fragments are affected by the residual atmospheric drag in the low orbit, continuously decrease in orbital altitude, and are burned up upon re-entry into the atmosphere. Example 3

[0033] An autonomous dismantling system for a large low-orbit spacecraft aluminum alloy frame 1, comprising an aluminum alloy frame 1, characterized in that: it further comprises an activation signal unit and a liquid metal trigger unit; the activation signal unit comprises a spacecraft receiver for receiving ground signals and a Peltier element 2 electrically connected to the spacecraft receiver; the spacecraft receiver receives signals sent by the ground control center via radio.

[0034] The liquid metal triggering unit includes liquid metal 5, a protective gate 3, and a storage chamber 4. Liquid metal 5 is a Ga-In-Sn alloy, comprising the following weight components: 13 wt.% Ga, 25 wt.% In, and 62 wt.% Sn; its melting point is 67°C. The protective gate 3 is a shape memory metal Au-Pd alloy, disposed between the liquid metal 5 and the aluminum alloy frame 1, isolating the liquid metal 5 from the aluminum alloy frame 1; the phase transition temperature of the Au-Pd alloy is 175°C. The storage chamber 4 is disposed on the surface of the liquid metal 5 to seal the liquid metal 5; the storage chamber 4 has a thickness of 80 μm and is made of shape memory polymer polyimide. Liquid metal 5 is a metal sheet with a thickness of 0.8 mm.

[0035] The control method for the autonomous disintegration system of the aluminum alloy frame 1 of the aforementioned large low-orbit spacecraft includes the following steps: ① Receiving ground signals: After the spacecraft completes its service life, the ground control center sends a signal to the spacecraft receiver. The spacecraft receiver sends a signal to activate Peltier element 2, causing Peltier element 2 to heat up to 183°C. ② The protective gate 3 opens: The Peltier element 2 causes the protective gate 3 to undergo a shape memory effect through heat conduction, causing the protective gate 3 to form multiple shapes such as... Figure 2 The liquid metal release channel 31 is shown. ③ Release and diffusion of liquid metal 5: Liquid metal 5 melts into a liquid state due to the heating effect of Peltier element 2. Under capillary action, it contacts the aluminum alloy skeleton 1 along the liquid metal release channel 31, and thus diffuses and penetrates into the aluminum alloy skeleton 1 along the grain boundaries. After 48 hours, the tensile strength of the aluminum alloy decreased from 462 MPa to 320 MPa.

[0036] ④ Spacecraft disintegration: Under vibration load, the aluminum alloy skeleton 1 fractures and decomposes along the embrittled region where the liquid metal 5 has penetrated, causing the aluminum alloy skeleton 1 to form small fragments; the small fragments are affected by the residual atmospheric drag in the low orbit, continuously decrease in orbital altitude, and are burned up upon re-entry into the atmosphere.

[0037] The mechanical properties of the aluminum alloy skeletons in Examples 1-3 were tested, and the results are shown in Table 1.

[0038] Table 1. Changes in tensile strength of aluminum alloys before and after the application of liquid metal.

Claims

1. A self-disassembly system for an aluminum alloy frame of a large low-orbit spacecraft, comprising an aluminum alloy frame (1), characterized in that: It also includes an activation signal unit and a liquid metal trigger unit; The activation signal unit is used to receive external signals and send an activation signal to the liquid metal trigger unit; The liquid metal triggering unit includes a storage chamber (4) for sealing liquid metal (5) and a protective gate (3); the protective gate (3) is located between the liquid metal (5) and the aluminum alloy frame (1) to isolate the liquid metal (5) and the aluminum alloy frame (1); After receiving the activation signal from the activation signal unit, the protective gate (3) releases liquid metal (5), which then contacts the aluminum alloy skeleton (1) and diffuses and penetrates into the aluminum alloy skeleton (1) along the grain boundaries of the aluminum alloy.

2. The autonomous disassembly system for the aluminum alloy skeleton of a large low-orbit spacecraft according to claim 1, characterized in that: The liquid metal (5) is a Ga-In-Sn alloy and includes the following components by weight: 10-20 wt.% Ga, 20-30 wt.% In and 50-70 wt.% Sn; the liquid metal (5) is a film or metal sheet with a thickness of 0.5-1 mm.

3. The autonomous disassembly system for the aluminum alloy skeleton of a large low-orbit spacecraft according to claim 1, characterized in that: The activation signal unit includes a spacecraft receiver for receiving ground signals and a Peltier element (2) electrically connected to the spacecraft receiver to emit thermal signals.

4. The autonomous disassembly system for the aluminum alloy skeleton of a large low-orbit spacecraft according to claim 3, characterized in that: The protective gate (3) is a shape memory metal Au-Pd alloy, and the phase transformation temperature of the Au-Pd alloy is 170-180℃.

5. The autonomous disassembly system for the aluminum alloy skeleton of a large low-orbit spacecraft according to claim 1, characterized in that: The storage chamber (4) is disposed on the surface of the aluminum alloy frame, and the thickness of the storage chamber (4) is 40-100μm; and the storage chamber (4) is a shape memory polymer.

6. A control method for an autonomous disintegration system of an aluminum alloy skeleton for a large low-orbit spacecraft as described in any one of claims 1-5, characterized in that: Includes the following steps: ① Receiving ground signals: After the activated signal unit receives the signal sent by the ground control center, it heats up to 180-200℃ and emits a heat signal; ② The protective gate (3) opens: The heat signal of the activation signal unit causes the protective gate (3) to have a shape memory effect through heat conduction, and multiple liquid metal release channels (31) are formed on the protective gate (3); ③ Liquid metal (5) release and diffusion: The liquid metal (5) melts into liquid due to the heating effect of the activation signal unit, and the liquid metal release channel (31) contacts the aluminum alloy skeleton (1), thereby diffusing and penetrating into the aluminum alloy skeleton (1) along the grain boundary of the aluminum alloy. ④ Spacecraft disintegration: Under vibration load, the aluminum alloy skeleton (1) breaks and decomposes along the embrittled area penetrated by the liquid metal (5), causing the aluminum alloy skeleton (1) to form small fragments. Small debris, dragged down by the residual atmospheric drag in low orbit, continued to descend in altitude and burned up upon re-entry into the atmosphere.

7. The control method for the autonomous disintegration system of the aluminum alloy skeleton of a large low-orbit spacecraft according to claim 6 is characterized in that: Step ① is as follows: After the spacecraft receiver receives the signal sent by the ground control center, the spacecraft receiver sends a signal to activate the Peltier element (2), so that the Peltier element (2) is heated to 180-200℃.

8. The control method for the autonomous disintegration system of the aluminum alloy skeleton of a large low-orbit spacecraft according to claim 6 is characterized in that: The spacecraft receiver receives signals sent by the ground control center via radio.

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