CN109264036B

CN109264036B - Off-orbit electric power rope system of spacecraft

Info

Publication number: CN109264036B
Application number: CN201811308255.9A
Authority: CN
Inventors: 师鹏; 雷冰瑶; 刘思帆; 程琦翔; 赵育善
Original assignee: Beihang University
Current assignee: Beihang University
Priority date: 2018-11-05
Filing date: 2018-11-05
Publication date: 2020-04-24
Anticipated expiration: 2038-11-05
Also published as: CN109264036A

Abstract

The invention relates to the technical field of spacecraft derailment, and discloses a spacecraft derailment electrodynamic force rope system which comprises an electrodynamic force rope and an air charging and discharging device, wherein the electrodynamic force rope comprises a conductive wire and an elastic layer sleeved outside the conductive wire, and the air charging and discharging device is connected with the electrodynamic force rope and is used for charging and discharging air into the elastic layer. The spacecraft off-orbit electrodynamic force tether provided by the invention is characterized in that the elastic layer sleeved outside the conductive wire is inflated by the inflation and deflation device to form an air column with internal air pressure and certain stretching tension, so that the electrodynamic force tether becomes a rod with certain bending and torsional rigidity in space, the stability of the electrodynamic force tether in space is improved, the problem that the effective length of the tether is reduced due to the fact that the tether is folded back is avoided, the axial line direction disturbance of the tether is not required to be considered, and the overall state control of the electrodynamic force tether is relatively simple. In addition, the modeling is convenient, so that the electric power rope system is more convenient and simpler in theoretical analysis and model operation.

Description

Off-orbit electric power rope system of spacecraft

Technical Field

The invention relates to the technical field of spacecraft derailment, in particular to a spacecraft derailment electric power rope system.

Background

With the increasing activity of human space, the space above the earth is becoming more crowded and the amount of satellites and space debris is increasing. According to statistics, the number of the artificial satellites orbiting around the earth is four thousand, three and more than hundred, and only one thousand, two and more than hundred are in normal operation. A large amount of space garbage including waste satellites seriously influences the development of human space activities, not only occupies precious orbit resources, but also brings great uncertainty and security threat to the normal operation of the in-orbit spacecraft. The space debris exists in large quantity from millimeter to dozens of centimeters, and the collision between the space debris and the existing debris collides with the running satellite to generate more new debris and cause the geometric progression increase of the space debris quantity. On 10 d 2.2009, space collision accidents occurred with russian obsolete satellite "universe 2251" and us "estuary 33", which was the first satellite collision accident in human history. For sustainable use of geospatial orbital resources, the generation of space junk must be effectively controlled. The active derailment of the mission-completed spacecraft to reduce the dead time is an important method for controlling and reducing space garbage.

The off-track method adopting the electric power rope system is a novel, convenient and energy-saving off-track method which is formed in recent years. The method only needs to install an off-track device which is lighter than the self-weight of the spacecraft, and then controls the rope system to work by utilizing electric energy, so that the control force can be brought to the whole spacecraft under the condition of not consuming fuel. After the spacecraft completes a space task, the electric power tether starts to release the tether, two ends of the tether are respectively connected with the spacecraft and the payload, and the tether and charges in the space form a closed loop by respectively installing plasma exchangers for charge collection and emission at two ends of the tether. Since the tether rapidly cuts the magnetic field lines of the landing magnetic field with the movement of the spacecraft, a large electromotive force is generated at both ends of the tether, causing directional movement of charges to induce an induced current on the tether. At this time, the electromagnetic field is cut by a live wire, and the generated Lorentz force can be used as power for controlling the movement of the spacecraft, so that the spacecraft can be quickly derailed. Further, the direction of current flow in the electric power roping and thus the direction of the lorentz force can also be controlled. When the included angle between the Lorentz force and the running speed direction of the spacecraft is smaller than 90 degrees, the acceleration force can be provided for the spacecraft, so that the orbit height of the spacecraft is increased; on the contrary, the spacecraft orbit height can be reduced by changing the current direction.

At present, although a complete spacecraft off-orbit space test actually carried out by utilizing an electric power rope system does not exist, a plurality of related space tests are carried out in many countries, and the feasibility of the method is verified. Research on theoretical aspects is a hot problem of research in various countries at present, and mainly comprises aspects such as mechanical model construction, dynamics control, ground simulation test and the like. Because the relatively thin electric power ropes are adopted in rail tests and theoretical researches, the length of the ropes in space is possible to change within the range of hundreds of meters to hundreds of kilometers, the shape and the state of the ropes can change along with the change of external force, the ropes cut earth magnetic field lines in the space environment, gravity gradient force and Lorentz force act on the electric power ropes with certain length, the space state of the electric power ropes can become unstable, and the kinematics analysis of the whole spacecraft can become inaccurate.

On the other hand, when theoretical research and off-track simulation are carried out, a theoretical model needs to be established for the electrodynamic force rope system, the existing rope system model comprises a rigid rod model, an elastic rod model, a chain rod model, a bead type model, a continuum model and the like, the model selection is closer to the actual situation, the calculation process is more complex, and the existing model cannot give consideration to good reality and the convenience of analysis and operation.

Disclosure of Invention

Technical problem to be solved

The invention aims to provide an off-orbit electric power tether of a spacecraft, which can improve the space stability of a tether, is convenient for integrally controlling the tether and is convenient for modeling analysis.

(II) technical scheme

In order to solve the technical problem, the invention provides an off-orbit electric power rope system for a spacecraft, which comprises an electric power rope and an air charging and discharging device, wherein the electric power rope comprises a conductive wire and an elastic layer sleeved outside the conductive wire, and the air charging and discharging device is connected with the electric power rope and is used for charging and discharging air into the elastic layer.

Wherein the electrodynamic cord further comprises a protective layer located outside the elastic layer.

The winding shaft is wound and unwound through rotation, the electric power rope is arranged in the winding shaft, an air passage is arranged in the winding shaft, a first port of the air passage is arranged on the side face of the winding shaft, the starting end of the elastic layer is sleeved on the first port, a second port of the air passage is arranged at the end face rotation center of the winding shaft and connected with the charging and discharging device, and the electric lead penetrates through the air passage and is connected with the plasma exchanger.

Wherein, it includes gas holder, solenoid valve and rotary joint to fill air bleeder, the solenoid valve includes air inlet, gas outlet and disappointing mouth, rotary joint includes stiff end and rotatory end, the air inlet is connected the gas holder, the gas outlet with the stiff end is connected, it is used for releasing to lose the mouth gaseous in the elastic layer, rotatory end with the second port is connected.

Wherein, rotary joint still includes rotary rod and sealed bearing, the rotary rod is hollow structure, rotary rod one end with second port fixed connection, the other end passes through sealed bearing with rotatory end rotatable coupling.

Wherein, the gas stored in the gas storage tank is high-pressure helium.

The tank body of the air storage tank is provided with a first air hole, a second air hole and a third air hole; the first air hole is connected with the air inlet and is used for inflating the elastic layer; the second air hole is connected with a pressure gauge and is used for measuring the pressure in the air storage tank; the third air hole is a spare hole.

The elastic layer is a graphene film, the thickness of the elastic layer is 0.18-0.22mm, and the outer diameter of the elastic layer is 4.5-5.5mm when no pressure difference exists between the inside and the outside.

The protective layer comprises an aramid fiber strength member and an overlapped layer of a high-melting-point aromatic polyamide woven net, the thickness of the protective layer is 0.45-0.55mm, and the outer diameter of the protective layer is 9-11 mm.

Wherein, the conductive wire is an aluminum wire, and the diameter of the aluminum wire is 0.8-1.2 mm.

(III) advantageous effects

Compared with the prior art, the invention has the following advantages:

according to the off-orbit electric power tether of the spacecraft, the inflation device is used for inflating the elastic layer sleeved outside the conductive wire, so that the elastic layer becomes an air column with internal air pressure and certain stretching tension, the electric power tether of the embodiment of the invention becomes a rod with certain bending and torsional rigidity in space, the stability of the electric power tether in space is improved, and the problem that the effective length of the tether is reduced due to the fact that the electric power tether is folded back is solved. Further, it is not necessary to consider the occurrence of disturbance in the axial direction of the tether, and the state control of the entire electric power tether is relatively simple. In addition, the electrodynamic force rope of the embodiment of the invention is approximately equivalent to a rod with bending rigidity, and is convenient to model, so that the electrodynamic force rope system is more convenient and simpler in theoretical analysis and model operation.

Drawings

FIG. 1 is a schematic diagram of an electric power cord structure according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of an off-orbit electric power tether structure of a spacecraft in accordance with an embodiment of the present invention;

in the figure: 1. a conductive wire; 2. an elastic layer; 3. a protective layer; 4. a spool; 5. a baffle disc; 6. a gas storage tank; 7. an electromagnetic valve; 8. a rotary joint; 9. an air escape opening; 10. an air hose; 11. a first air hole; 12. a second air hole; 13. a third air hole; 14. an air pressure sensor interface.

Detailed Description

The following detailed description of embodiments of the present invention is provided in connection with the accompanying drawings and examples. The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention.

In the description of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," "third," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood as appropriate by those of ordinary skill in the art.

In addition, in the description of the present invention, "a plurality", and "a plurality" mean two or more unless otherwise specified.

As shown in fig. 1 and 2, the off-orbit electric power tether for a spacecraft according to an embodiment of the present invention includes an electric power tether and an inflation/deflation device, wherein the electric power tether includes a conductive wire 1 and an elastic layer 2 sleeved outside the conductive wire, and the inflation/deflation device is connected to the electric power tether and is configured to inflate/deflate air into the elastic layer 2. According to the off-orbit electric power tether of the spacecraft, the elastic layer 2 sleeved outside the conductive wire is inflated through the inflation and deflation device, so that the elastic layer 2 becomes an air column with internal air pressure and certain stretching tension, the electric power tether of the embodiment of the invention becomes a rod with certain bending and torsion rigidity in space, the stability of the electric power tether in space is improved, and the problem that the effective length of the tether is reduced due to the fact that the tether is folded backwards is avoided. Further, it is not necessary to consider the occurrence of disturbance in the axial direction of the tether, and the state control of the entire electric power tether is relatively simple. In addition, the electrodynamic force rope of the embodiment of the invention is approximately equivalent to a rod with bending rigidity, and is convenient to model, so that the electrodynamic force rope system is more convenient and simpler in theoretical analysis and model operation.

According to the off-orbit electrodynamic force tether of the spacecraft, provided by the embodiment of the invention, the protective layer 3 can be sleeved outside the elastic layer 2. The elastic layer 2 can be made of high-strength elastic material, and can expand after being inflated to form a gas column with certain internal pressure. The protective layer 3 can be made of high molecular polymer with certain strength, which can not only provide certain protection for the elastic layer 2 in a severe space environment, but also can form certain restriction for the expansion of the elastic layer 2. Further, the conductive wire of the embodiment of the invention can adopt a conventional aluminum wire, and the diameter can be 0.8-1.2 mm; the elastic layer 2 can adopt a graphene film with certain elasticity and toughness, the thickness is 0.18-0.22mm, and the outer diameter is 4.5-5.5mm when the film is not inflated or has no pressure difference between the inside and the outside; the protective layer 3 can be an overlapping layer of an aramid fiber strength member and a high-melting-point aromatic polyamide woven mesh, the thickness is 0.45-0.55mm, and the outer diameter is 9-11mm in an uninflated state. In the state that the electric power rope is not used, the elastic layer 2 can be in vacuum state, and the elastic layer is stored in the state of minimum volume so as to save precious space of the spacecraft. Can be vacuum state between elastic layer 2 and the protective layer 3, when elastic layer 2 was in the gas filled state, elastic layer 2 can expand and closely laminate with the protective layer, and protective layer 3 is to elastic layer 2 its to certain constraint effect of inflation to increase the inflation pressure in elastic layer 2 to a certain extent, and then strengthen the extension tension of electrodynamic force rope gas column.

Further, the spacecraft off-orbit electric power tether of the embodiment of the invention can further comprise a winding shaft 4 for winding the electric power tether, and the winding shaft 4 winds and unwinds the electric power tether through rotation. The two ends of the winding shaft 4 can be provided with baffle discs 5 to form a containing space of the electric power rope. When not in use, the electric power rope is wound on the winding shaft 4; when needed, the spool 4 is rotated and the electrodynamic cord is released; after use, the spool can be rotated in reverse and the power cord withdrawn. An air passage is arranged in the winding shaft 4, and the inflation and deflation device is connected with the air passage of the elastic layer 2 of the electrodynamic force rope through the air passage and inflates and deflates air into the elastic layer 2. The air flue can set up two ports, and 4 sides of spool are located to first port, and the initiating terminal of elastic layer 2 cup joints at first port, and electric power rope's conductor wire 1 can pass the air flue and be connected with plasma exchanger, and spool terminal surface rotation center is located to the second port, is connected with inflating and deflating device. Can be at the initiating terminal installation nut of electric power rope elastic layer 2 as electric power rope inflation and deflation port, elastic layer 2 closely cup joints at the nut surface to through threaded connection with electric power rope fixed connection to the first port of 4 air flues of spool.

The air charging and discharging device of the embodiment of the invention can comprise an air storage tank 6, an electromagnetic valve 7 and a rotary joint 8. The gas storage tank 6 is used for storing high-pressure gas, and the high-pressure gas can adopt helium gas with light specific gravity and stable chemical properties. The electromagnetic valve 7 can work normally under vacuum, negative pressure and zero pressure, parameters such as flow, speed and the like of gas passing can be controlled and adjusted through electric signals, and the electromagnetic valve 7 can be selected to control charging and discharging of the electrodynamic force rope system. The solenoid valve 7 may include an air inlet, an air outlet, and an air release 9, and the rotary joint may include a fixed end and a rotary end. An air inlet of the electromagnetic valve 7 can be connected with the air storage tank 6 through an air hose 10. The air hose 10 can be made of a common PVC plastic hose, and threaded joints are fixed at two ends of the air hose to facilitate connection with each air breather. The gas outlet of solenoid valve 7 is connected with rotary joint 8's stiff end, and disappointing mouth 9 of solenoid valve 7 is used for the gas in the elastic layer 2 of bleeding, and rotary joint 8's rotatory end is connected with the second port of 4 air flues of spool. Further, the rotary joint 8 may further include a rotary rod and a seal bearing. The rotary rod is of a hollow structure, one end of the rotary rod is fixedly connected with the second port of the air passage of the winding shaft 4, and the other end of the rotary rod is rotatably connected with the rotary end through a sealing bearing. Therefore, the high-pressure gas stored in the gas storage tank 6 is connected with the gas inlet of the electromagnetic valve 7 through the ventilation hose 10, when the electromagnetic valve 7 is controlled to be inflated, the high-pressure gas enters the rotary joint 8 from the gas outlet of the electromagnetic valve 7 and further enters the gas channel of the winding shaft 4 through the hollow rotary rod, and finally is inflated into the elastic layer 2 of the electrodynamic force rope. When the gas in the elastic layer 2 needs to be discharged, the electromagnetic valve 7 is controlled to open the gas release port 9 and close the gas inlet, so that the space in the elastic layer 2 is communicated with the external space, and the gas discharge is completed. In addition, an air pressure sensor interface 14 can be additionally arranged in the rotary joint 8 or the air passage and used for measuring the air pressure in the elastic layer 2, sending a pressure signal to the control system to form a feedback signal for controlling and adjusting the pressure in the elastic layer 2, and completing the adjustment and control of the pressure in the elastic layer 2 through the electromagnetic valve 7.

A plurality of holes are formed in the tank body of the air storage tank 6 in the embodiment of the invention, for example, a first air hole 11 connected with an air inlet of the electromagnetic valve 7 can be arranged and used for inflating the elastic layer 2; a second air hole 12 connected with a pressure gauge can be arranged for measuring the pressure in the air storage tank 6; a third gas vent 13 may also be provided as a backup vent to provide a redundant backup and facilitate gas use in other parts of the spacecraft.

The off-orbit electric power rope system of the spacecraft provided by the embodiment of the invention can have four working states:

1) a dormant state. In the process of completing space tasks by the spacecraft, when the off-orbit operation is not needed, the off-orbit system is in a dormant state, and all components are in a power-off state.

2) Releasing the tether state. When the spacecraft needs to be off-orbit, the off-orbit electric power tether of the spacecraft is electrified, the tether is firstly released to a specified length under a certain rule, then the control system controls the electromagnetic valve 7 to be opened and closed, and the elastic layer 2 in the tether is filled with a proper amount of gas, so that the electric power tether is changed into a long rod state with certain rigidity and torsional strength.

3) And maintaining and off-track state. The plasma exchanger in the spacecraft off-track system starts to work, the electric conductor 1 of the electric power rope starts to generate current, and the spacecraft can be quickly off-track under the action of Lorentz force. The physical quantity such as attitude angle of the tether in the space can be controlled by controlling the current in the tether through the control system.

4) And recovering the tied rope in a packaged state. After the spacecraft is successfully derailed, the air leakage port 9 of the electromagnetic valve 7 is opened, the air in the tether is exhausted and then is closed, and then the tether is recovered.

Further, according to the spacecraft off-orbit electrodynamic force tether disclosed by the embodiment of the invention, the conducting wire 1 is an aluminum wire with the diameter of 1 mm; the elastic layer 2 is a graphene film with the thickness of 0.2mm, and the outer diameter of the elastic layer is 5mm in an uninflated state; the protective layer 3 is a superposed layer of an aramid fiber strength member and a high-melting-point aromatic polyamide woven mesh, the thickness is 0.5mm, and the outer diameter is 10mm in an uninflated state. On the basis, the length of the electric power rope is set to be 5km, and the mass and space budget of the off-orbit electric power rope system of the spacecraft is carried out according to the embodiment of the invention. The mass of the gas storage tank 6 is estimated to be 2000g, and the volume is estimated to be 300mm (length) 160mm (width) 190mm (height); the mass of the solenoid valve 7 is estimated to be 200g, and the volume is estimated to be 60mm (length) 40mm (width) 110mm (height), while the overall calculation can be performed for two solenoid valves 7. The mass of the elastic layer 2 and the protective layer 3 outside the electrically conductive wire 1 of the electrodynamic rope is 500g, so that the spacecraft adopting the off-orbit electrodynamic force rope system of the spacecraft of the embodiment of the invention has the mass increase of about 3000g and the volume increment of about 400mm (length) 200mm (width) 200mm (height) compared with the traditional rope system.

It can be seen from the above embodiments that the spacecraft off-orbit electric power tether provided by the embodiment of the present invention inflates air into the elastic layer 2 wrapped outside the conductive wire 1 through the air inflation and deflation device, so that the elastic layer 2 becomes an air column with internal air pressure and certain stretching tension, and further the electric power tether of the embodiment of the present invention becomes a rod with certain bending and torsional rigidity in space, thereby improving the stability of the electric power tether in space and avoiding the problem of the effective length reduction of the tether caused by folding back. Further, it is not necessary to consider the occurrence of disturbance in the axial direction of the tether, and the state control of the entire electric power tether is relatively simple. In addition, the electrodynamic force rope of the embodiment of the invention is approximately equivalent to a rod with bending rigidity, and is convenient to model, so that the electrodynamic force rope system is more convenient and simpler in theoretical analysis and model operation. Further, a protective layer 3 can be arranged outside the elastic layer 2, so that the elastic layer 2 can be protected to a certain extent in a severe space environment, and the expansion of the elastic layer 2 can be restrained to a certain extent.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.

Claims

1. The off-orbit electrodynamic force tether of the spacecraft is characterized by comprising an electrodynamic force tether and a charging and discharging device, wherein the electrodynamic force tether comprises a conductive wire and an elastic layer sleeved outside the conductive wire, and the charging and discharging device is connected with the electrodynamic force tether and is used for charging and discharging air into and out of the elastic layer;

the winding shaft is used for winding the electrodynamic force rope, an air passage is arranged in the winding shaft, a first port of the air passage is arranged on the side face of the winding shaft, the starting end of the elastic layer is sleeved on the first port, the conducting wire penetrates through the air passage and is connected with the plasma exchanger, and a second port of the air passage is arranged at the end face rotation center of the winding shaft and is connected with the charging and discharging device.

2. A spacecraft off-orbit electrical power tether of claim 1, wherein the electrical power tether further comprises a protective layer located outside the elastic layer.

3. The off-orbit electric power tether of spacecraft of claim 1, wherein the inflation and deflation device comprises a gas storage tank, a solenoid valve and a rotary joint, the solenoid valve comprises a gas inlet, a gas outlet and a gas release opening, the rotary joint comprises a fixed end and a rotating end, the gas inlet is connected with the gas storage tank, the gas outlet is connected with the fixed end, the gas release opening is used for releasing gas in the elastic layer, and the rotating end is connected with the second port.

4. A spacecraft off-orbit electrical power tether of claim 3, wherein the swivel joint further comprises a swivel rod and a sealed bearing, the swivel rod is of a hollow structure, one end of the swivel rod is fixedly connected with the second port, and the other end of the swivel rod is rotatably connected with the swivel end through the sealed bearing.

5. A spacecraft off-orbit electrical power tether of claim 3, wherein the stored gas within the gas tank is helium at high pressure.

6. A spacecraft off-orbit electric power tether of claim 3, wherein the tank body of the air tank is provided with a first air hole, a second air hole and a third air hole; the first air hole is connected with the air inlet and is used for inflating the elastic layer; the second air hole is connected with a pressure gauge and is used for measuring the pressure in the air storage tank; the third air hole is a spare hole.

7. A spacecraft off-orbit electrical power tether as claimed in claim 1, wherein the elastic layer is a graphene film having a thickness of 0.18-0.22mm and an outer diameter of 4.5-5.5mm when there is no pressure difference between the inside and outside.

8. A spacecraft off-orbit electrical powered tether of claim 2, wherein the protective layer comprises a stack of aramid fiber strength members and woven high melting point aramid mesh, the protective layer having a thickness of 0.45-0.55mm and an outer diameter of 9-11 mm.

9. A spacecraft off-orbit electrical power tether as claimed in claim 1, wherein the electrically conductive wire is an aluminium wire having a diameter of 0.8-1.2 mm.