Separation method for light and small reentry and reentry capsule

Abstract

The invention relates to a separation method for a light and small reentry and return capsule, and belongs to the technical field of spacecraft reentry and return. Firstly, a main detector sends out a control instruction, and power supply and communication between the main detector and the return capsule are stopped; then, at a set moment, the main detector sends a cable cutting instruction to cut off the cable between the cabins at one time; and the main detector stops attitude control and then sends an unlocking instruction, the reentry capsule is unlocked, and the main detector drives the reentry capsule to be separated. The motion amplitude of the reentry capsule around a non-spinning shaft is reduced through an attitude damping system on the reentry capsule, so that the attitude of the reentry capsule meets the reentry requirement. According to the invention, an electrical separation mode is realized by adopting the hot working cutter; the electrical separation mode realized by adopting the hot working cutter to cut off a cable between cabins can effectively avoid the uncertain service life of a long-term on-orbit separation electric connector of the reentry capsule, the reduction of the separation reliability, possible abnormal conditions such as vacuum cold welding and the like; and reliable separation of electrical connection between the cabins is realized.

Description

Technical Field

[0001] This invention belongs to the field of spacecraft reentry and return technology, specifically relating to a separation method for a lightweight reentry and return capsule. Background Technology

[0002] Sample return from extraterrestrial objects is an important form of deep space exploration. After collecting samples from extraterrestrial objects with the main probe, the return capsule returns to Earth, separates from the main probe near Earth, and then flies independently for a period of time before re-entering the Earth's atmosphere and landing safely, thus achieving sample return. For lightweight re-entry capsules, due to mass constraints, they generally lack an attitude control system. After separating from the main probe, they enter a free-flight state, and the capsule's attitude is determined by the disturbance introduced at the moment of separation. To ensure that the capsule's attitude meets re-entry requirements, the principle of spin-axis fixation is often used after separation. This allows the capsule to suppress attitude disturbances caused by the separation process through spin motion, preventing attitude divergence after separation and ensuring that it meets attitude re-entry requirements during free flight. The separation process generally includes: electrical separation, mechanical separation, and capsule spin-up.

[0003] As deep space probes venture into deeper space, sample return missions face longer on-orbit flight times and more stringent resource constraints. Due to the longer on-orbit flight time, the reliability and safety of the separation process of the inter-vessel connection and separation device are greatly affected by environmental factors, requiring a simple and reliable separation method. Furthermore, due to mass resource constraints, lightweight reentry capsules have limited means to suppress disturbances during separation, and maintaining the reentry attitude of the capsule after free flight is challenging. Traditional spacecraft separation schemes have the following shortcomings: 1) In the past, electrical connectors were used to achieve electrical connection between the cabins. After long-term flight in orbit, the state of the electrical connectors is uncertain due to environmental influences, which may lead to situations such as vacuum cold welding. The uncertainty is high, ground verification is difficult, and reliable separation of electrical connections cannot be guaranteed. 2) In the past, the return capsule and the main detector usually separated first, and then the return capsule started to rotate. This method could not determine the state of the return capsule when it started to rotate, and the state of the return capsule after it started to rotate was uncertain. 3) In the past, reentry capsules often used small spinning rockets to initiate their rotation, and then relied on spin stabilization to maintain their attitude after separation. This method involved a large mass, which is not feasible for lightweight and small reentry capsules. Furthermore, due to the small mass of the reentry capsule, the attitude stabilization accuracy of this method was low, resulting in significant uncertainty in the reentry attitude. Summary of the Invention

[0004] The purpose of this invention is to overcome the above-mentioned defects of the prior art and provide a separation method for a lightweight reentry capsule, which can reliably separate the electrical and mechanical structural connections between the reentry capsule and the main detector under the condition of limited reentry capsule resources.

[0005] The above-mentioned objectives of the present invention are mainly achieved through the following technical solutions: A separation method for a lightweight reentry capsule includes the following steps: (1) The main probe sends a control command, and the main probe and the return capsule stop receiving power and communicating. (2) At the set time, the main detector sends a cable cutting command to cut the inter-cabin cable in one go; (3) The main probe stops attitude control, then issues an unlocking command, the return capsule unlocks, and the main probe drives the return capsule to separate.

[0006] In step (2), a fire-cutting tool is used to cut the cable.

[0007] In step (2), after the cable is cut, the main detector and the return capsule are mechanically connected.

[0008] In step (2), after the cable is cut, the remaining cable is stored in the return capsule using a cable storage device and then heat-sealed.

[0009] In step (3), attitude control is stopped one second before unlocking and separation.

[0010] In step (3), a spiral guide rail is provided on the main detector. After the return capsule is unlocked from the main detector, the return capsule is driven by a spring to move along the spiral guide rail and start to spin and separate.

[0011] In step (3), after the return capsule separates, the amplitude of the return capsule's motion around the non-spin axis is reduced by the attitude damping system on the return capsule, so that the attitude of the return capsule meets the reentry requirements.

[0012] The attitude damping system operates for no more than 20 minutes. After the attitude damping system stops working, the return capsule flies freely to the reentry point for reentry.

[0013] In step (3), a separation point is set, and after the main detector reaches the separation point, it issues an unlocking command.

[0014] Compared with the prior art, the present invention has at least the following beneficial effects: (1) The present invention can reliably separate the electrical and mechanical structure connection between the return capsule and the main detector under the condition of limited return capsule resources.

[0015] (2) The preferred embodiment of the present invention is to use a pyrotechnic cutter to achieve electrical separation: the method of using a pyrotechnic cutter to cut the inter-cabin cable can effectively avoid the uncertainty of the lifespan of the electrical connectors of the return capsule during long-term on-orbit separation, the decrease in separation reliability, and the possible abnormal situation such as vacuum cold welding, so as to achieve reliable separation of electrical connections between the spacecraft and the cabin. (3) The preferred method of achieving heat sealing of the return capsule by shrinking the cabin cable in the embodiment of the present invention is as follows: After the cabin cable is cut, the remaining cable is stored in the return capsule using a cable storage device and heat-sealed with cotton felt pads. This avoids the danger of the cable forming a heat stagnation point outside the capsule during the re-entry process and transferring external heat flow to the inside. The heat sealing of the cotton felt pads can prevent the external high-temperature airflow from entering the return capsule. (4) In this embodiment of the invention, the separation and spin-starting processes are preferably performed simultaneously by a single spin-starting separation mechanism. After the capsule separates, the main detector uses a spring to push the return capsule out. The separation mechanism is designed with a spiral slide, which provides rotational torque at the same time as pushing out the return capsule, so that the return capsule spins while separating. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the separation method of the present invention. Detailed Implementation

[0017] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments: The technical solution of this invention is as follows: Based on the separation requirements between the return capsule and the main detector, a reliable electrical separation method is selected to separate the electrical separation process from the mechanical separation process, avoiding the electrical separation process from affecting the mechanical separation process; the mechanical separation process combines the unlocking separation and the spin-starting action of the return capsule, making the mechanical separation spin-starting link simple and reliable, and further reducing the attitude disturbance of the return capsule during the separation process; after the main detector and the return capsule are completely separated, the return capsule uses limited resources to configure a short-term working attitude damping system to further suppress the precession and nutation amplitude caused by disturbances on the basis of the return capsule's spin motion, so that the return capsule's attitude meets the re-entry requirements.

[0018] like Figure 1 As shown, the new separation scheme for the lightweight reentry capsule consists of three parts: electrical separation, mechanical separation, and post-separation attitude damping, as detailed below: 1) Electrical separation Ionization separation is achieved using a pyrotechnic cutter. Before the mechanical separation of the reentry capsule, a pyrotechnic ignition command is sent to cut the communication and power cables between the capsules, thus achieving electrical separation. The specific electrical separation process is as follows: a) Preparation: Before cutting the spacecraft cable, the main detector turns on the power supply switch of the return capsule battery pack through a command and turns off the main detector power supply switch of the return capsule. The return capsule switches to internal power supply, and there is no current in the power supply cable in the spacecraft cable. The main detector turns on the equipment on the return capsule through a command and enters the reentry mode. Communication between the spacecraft and the spacecraft stops, and there is no signal in the communication cable. The above preparation can reduce the risk of short circuit caused by cable splicing when cutting the cable.

[0019] b) Cabin Cable Cutting: After preparation, at a predetermined time, the main detector issues a cable cutting command to cut the inter-cabin cables in one go. Using pyrotechnic cutting can effectively avoid the uncertainties that may be caused by long-term on-orbit storage of electrical connectors, and the cable cutting method does not need to consider the design margin of mechanical force-free disconnection when the electrical connector cannot be electrically separated, making the separation process reliable.

[0020] c) Separation of electromechanical components: After the cabin cables are cut, the return capsule and the main detector remain mechanically connected. The disturbance caused by the pyrotechnic cutting process will not enter the mechanical separation process, and the separation process will not affect the attitude of the return capsule.

[0021] 2) Mechanical separation According to the predetermined procedure, the main probe ceases attitude control and then issues a command to unlock and separate the return capsule. The return capsule unlocks from the main probe, and the main probe, via a spring-driven spin-starting separation mechanism, pushes the return capsule away from the main probe and causes it to spin. The mechanical separation process is as follows: a) Main probe stops control: 1 second before separation, the main probe stops attitude control. At this time, the return capsule is mechanically connected to the main probe. Stopping control can eliminate the attitude disturbance of the return capsule by the main probe attitude control system during separation. b) Spinning Separation: After the main detector stops, it immediately issues an unlocking command, and the return capsule unlocks from the main detector. At this time, the spring pressure of the spinning separation mechanism between the return capsule and the main detector is released, and the spinning separation mechanism drives the return capsule to push the main detector along the spiral guide rail. As the spinning separation mechanism moves along the spiral guide rail, it generates a rotational torque while applying thrust to the return capsule, causing the return capsule to rotate around its axis of symmetry. That is, the separation and spinning separation are carried out simultaneously.

[0022] 3) Attitude damping After the return capsule completely separates from the main probe, the attitude damping system, which is equipped on the return capsule and can operate for short periods, further reduces the amplitude of the return capsule's motion around its non-spin axis, ensuring its attitude meets reentry requirements. The mechanical separation process is as follows: After complete separation, the attitude damping system automatically determines whether the return capsule's attitude meets the requirements. If not, it applies an attitude damping torque to reduce the influence of the disturbance torque during mechanical separation, thereby further reducing the precession and nutation angles of the return capsule's spin motion, ensuring it meets reentry attitude requirements.

[0023] This invention proposes a novel separation scheme for lightweight reentry capsules, the specific implementation steps of which are as follows: 1) Return preparation: The main probe transmits the separation control commands to the return capsule. After separation, the return capsule automatically executes the relevant commands and completes subsequent procedures such as attitude damping stabilization. 2) Switch to internal power: The power supply switch for the return capsule's battery pack is turned on, and the power supply switch from the main detector to the return capsule is turned off, allowing the return capsule to supply its own power. 3) Carrier ionization separation: After the program injection and power supply conversion are completed, according to the return program, the main detector issues a carrier cable cutting command, and the pyrotechnic cutter cuts the cable between the return capsule and the main detector to achieve electrical separation of the carrier; 4) Re-entry capsule spin separation: Upon reaching the separation point, the main probe issues a capsule unlocking command according to the return program, pushing the re-entry capsule away from the main probe. At the same time, the re-entry capsule spins, and through spin stability, the disturbance torque generated during the separation process is converted into precession and nutation angles in the spin motion. 5) Attitude damping stabilization after separation: After separation, the return capsule automatically performs attitude damping stabilization control. If the disturbance during the separation process is too large, the attitude damping system will further control the precession and nutation amplitudes of the return capsule's spin motion to ensure that the return capsule's attitude meets the reentry requirements. 6) Stop Control: The attitude damping stabilization system is subject to resource constraints and its working time shall not exceed 20 minutes. After the attitude stabilization is completed, the system will stop working, the return capsule will complete the separation process and fly freely to the reentry point for reentry.

[0024] The above description is only the best specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the protection scope of the present invention.

[0025] The contents not described in detail in this specification are common knowledge to those skilled in the art.

Claims

1. A separation method for a lightweight reentry capsule, characterized in that: Includes the following steps: (1) The main probe sends a control command, and the main probe and the return capsule stop receiving power and communicating. (2) At the set time, the main detector sends a cable cutting command to cut the inter-cabin cable in one go; (3) The main probe stops attitude control, then issues an unlocking command, the return capsule unlocks, and the main probe drives the return capsule to separate.

2. The separation method for a lightweight reentry capsule according to claim 1, characterized in that: In step (2), a fire-cutting tool is used to cut the cable.

3. The separation method for a lightweight reentry capsule according to claim 1, characterized in that: In step (2), after the cable is cut, the main detector and the return capsule are mechanically connected.

4. The separation method for a lightweight reentry capsule according to claim 1, characterized in that: In step (2), after the cable is cut, the remaining cable is stored in the return capsule using a cable storage device and then heat-sealed.

5. The separation method for a lightweight reentry capsule according to claim 1, characterized in that: In step (3), attitude control is stopped one second before unlocking and separation.

6. The separation method for a lightweight reentry capsule according to claim 1, characterized in that: In step (3), a spiral guide rail is provided on the main detector. After the return capsule is unlocked from the main detector, the return capsule is driven by a spring to move along the spiral guide rail and start to spin and separate.

7. The separation method for a lightweight reentry capsule according to claim 1, characterized in that: In step (3), after the return capsule separates, the amplitude of the return capsule's motion around the non-spin axis is reduced by the attitude damping system on the return capsule, so that the attitude of the return capsule meets the reentry requirements.

8. The separation method for a lightweight reentry capsule according to claim 7, characterized in that: The attitude damping system operates for no more than 20 minutes. After the attitude damping system stops working, the return capsule flies freely to the reentry point for reentry.

9. The separation method for a lightweight reentry capsule according to claim 1, characterized in that: In step (3), a separation point is set, and after the main detector reaches the separation point, it issues an unlocking command.

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