JP2010069973A - Space debris removal method and its device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a space debris removal method and its device descending a fine particle of the space debris existing in an earth low orbit of the cosmos space by the force of an electric field, making the fine particle rushing into an atmosphere and burning it. <P>SOLUTION: The space debris removal method and its device enlarge a mesh-like charged body 5 becoming a mesh-like electrode 5e positively biased into a plasma existing in the earth low orbit 8 and charge the debris 1, i.e., the fine particle of 1 mm or less flying to a periphery of the mesh-like electrode 5e to negative by an electron e accelerated on the periphery of the mesh-like electrode 5e. In the method and the device, the debris 1 is decelerated by the force of the electric field of the mesh-like electrode 5e, the orbit of the debris 1 is descended, and the debris 1 is made rushing into the atmosphere 3 to be burned. The mesh-like charged body 5 is applied to a pulse form in the plasma to constitute it to the mesh-like electrode 5e. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a space debris removal method and an apparatus for removing space debris, for example, fine particles floating in space or space debris from a polar orbit.

  In recent years, due to the construction of a space station, the launch of an artificial satellite, etc., the outer space around the earth is considerably contaminated by space debris, which are artificial objects such as artificial satellite fragments, peeled paint, and fine particles released from the satellite. This is a big problem for these space debris. Debris means debris, and space debris is an artificial object flying in low earth orbit in outer space that does not play a useful role, particularly in a region within 2000 km from the surface of the earth. Space debris orbits in low earth orbit at an average speed of 10 km / sec. When such a high-speed space debris collides with an object such as an artificial satellite, a launched space rocket, or a worker in space. The destruction energy is large, and it is clear that damages such as easily drilling holes are made in objects, and serious accidents and fatal damages are starting to be seen as problems in artificial satellites and space rockets. . At present, space debris observation capability is less than about 10 cm in diameter, and tracking systems such as laser observation and optical observation cannot track and catch such particles because the space debris is too small. At present, the occurrence of accidents due to space debris cannot be avoided in advance.

  Currently, as a method for removing space debris, measures are taken to attach bumpers to the satellites to prevent the satellites from directly colliding with the space debris, or to apply processing that is difficult to generate debris when manufacturing the satellites themselves. However, it is technically difficult to make an artificial satellite so that debris does not occur, and it is impossible to avoid the fact that a used artificial satellite becomes space waste. is there. A typical whipple bumper is known among these space debris removal devices. The whipple bumper has a structure in which a thin metal plate is placed outside the spacecraft. Therefore, debris first collides with the metal plate, and a hole is opened in the metal plate by the collision of debris. Also, since it breaks up or disappears due to the collision, the collision energy can be dispersed and the damage to the outer wall can be reduced.

  Also known is a debris crushing satellite that crushes space debris that may collide with astronauts in manned space activities. In the debris grinding satellite, a thin metal plate that can be crushed by colliding and penetrating space debris is spread over the entire inner surface of a rectangular frame and installed in a space orbit, and a gas jet device is provided at each corner. A bus device is provided that controls the gas jet device to adjust the position and posture of the metal plate. Attach a posture stabilization mast to the end of the frame on the outer circumference of the Earth orbit. The position and attitude of the metal plate are adjusted by controlling each gas jet device, and the metal plate is placed in front of the spacecraft in the orbit around the earth in front of the space where manned space activity is scheduled. Used so as to cover. The flying space debris collides with a metal plate in advance and is pulverized to reduce the size (see, for example, Patent Document 1).

Also known is a space debris trajectory conversion tether device that is connected to a robot arm to enable power supply and signal exchange, and capture and release the target satellites to be dumped and collected. ing. The space debris trajectory conversion tether device grips a tether device including a capture mechanism, a handle, and a tether mechanism by a gripping mechanism provided on a robot arm. When the gripping mechanism is coupled to the handle, the tether device can be operated by the robot arm, and power supply for driving the capture mechanism and the tether mechanism and exchange of work information signals such as sensor signals and control signals can be performed. It becomes possible. When the extension of the tether is completed, the coupling between the gripping mechanism and the handle is separated, and the tether device provided with the gripping mechanism is released integrally with the target satellite and used in a disposable manner (see, for example, Patent Document 2).
Japanese Patent Laid-Open No. 2002-2599 JP 2004-98959 A

  By the way, if the space debris is left unattended, it will not disappear naturally. For example, the space debris in the space of the altitude of 200 km to 500 km, which is a low earth orbit, due to the maximum period of solar activity that occurs every 11 years. About 30% has been removed. However, at present, removal of space debris due to natural phenomena as described above is not sufficient for the proliferation of space debris, and the number of space debris in all orbits is constantly increasing year by year. It is necessary to artificially remove this from the orbit.

  Also, when space debris collides with each other or a satellite, new debris is generated thereby. When the debris spatial density exceeds a certain critical value, the debris generated by the collision causes the next collision in a chain, and the debris self-proliferates. Once debris starts self-replication in the universe, the number of debris increases at an accelerated rate, and even if a rocket is launched, it will be blocked by the debris. It is feared that it will be impossible.

  An object of the present invention is to solve the above-mentioned problem, in order to use a plasma environment in outer space to negatively charge fine debris, that is, space debris of fine particles existing in the space, and to reduce the speed of debris. This is to intentionally lower the height of the debris by applying the force of the electric field, and to inject and remove the debris into the atmosphere. In particular, the debris removal is focused on debris with a diameter of 10 cm or less. A large net-like net-like charged body is expanded in outer space, the net-type charged body is positively biased to be converted into a net-like electrode, and an electron sheath, that is, a negative sheath region around it. The debris that jumps into it is charged negatively by the negative sheath region at once, and the kinetic energy of the debris is canceled by the force of the electric field when the debris passes through the mesh electrode. Decelerating Te, then if enter the atmosphere debris dropped altitude, it is to provide a space debris removal method and apparatus utilizing a space plasma incineration by friction with the atmospheric drag.

  In the present invention, a net-like charged body is expanded and arranged in a vacuum plasma existing in a low earth orbit, the net-like charged body is positively biased to form a net-like electrode, and accelerated electrons around the net-like electrode are arranged. The space debris of fine particles flying around the mesh electrode is negatively charged, and the space debris is decelerated by the force of the electric field of the mesh electrode to lower the orbit of the space debris, and the space debris enters the atmosphere. It is related with the space debris removal method characterized by making it incinerate.

  In this space debris removal method, an electron sheath is formed around the positively biased mesh electrode, and the space debris flying into the electron sheath is negatively charged. In this space debris removal method, the mesh charged body is applied in pulses in the plasma to form the mesh electrode. Furthermore, in this space debris removal method, the space debris acts particularly effectively on fine particles having a diameter of 1 mm or less.

  The present invention also provides a network charged body spread in a vacuum plasma existing in a low earth orbit, and a power supply for connecting the network charged body and applying a voltage to positively bias the network charged body with respect to a plasma potential. And an artificial satellite for housing the power supply device and grounding the power supply device, and energizing the power supply device to positively bias the reticulated charged body to form a reticulated electrode, around the reticulated electrode An electron sheath is formed, and the space debris of the fine particles flying into the electron sheath is negatively charged. The negatively charged space debris is decelerated by the force of the electric field of the mesh electrode to lower the trajectory. It is related with the space debris removal apparatus characterized by injecting into the atmosphere and incinerating.

  In this space debris removal apparatus, the mesh-like charged body is applied in pulses in the plasma to constitute the mesh-like electrode. Moreover, in this space debris removal apparatus, the space debris acts particularly effectively on fine particles having a diameter of 1 mm or less. Furthermore, the net-like charged body is launched into the low earth orbit by the artificial satellite and is expanded to 1 km to several km square in the low earth orbit.

  Since the space debris removal method and apparatus using space plasma according to the present invention are configured as described above, the space debris, which are fine particles having a diameter of 1 mm or less, for example, 10 μm to 1 mm in diameter, are passed through the mesh electrode. As a result, the orbit of the space debris can be changed in the descending direction, the space debris can enter the atmosphere, and can be incinerated by frictional heat with the atmosphere. If the net-like charged body is a small one that expands to 1 km square, several pieces should be arranged in low earth orbit as appropriate, and if it is a large one that spreads to several km square, one machine is enough. Space debris can be removed. This space debris removal device is a simple structure consisting of a net-like charged body and a power supply device for charging it, and is a simple device that only changes the orbit of the space debris to a lowered orbit by the electric field force. Yes, if the mesh electrode descends and enters the atmosphere, it itself will be incinerated and will not become long-term space debris. Moreover, as a power supply device, it is possible to use electric power from a solar cell, and the running cost can be reduced.

  Hereinafter, a space debris removal method and apparatus using space plasma according to the present invention will be described with reference to the drawings. First, the principle of the technical idea of the present invention will be described with reference to FIG. 1, FIG. 2 and FIG. This space debris removal method and its apparatus is a small space debris 1 (hereinafter referred to as debris 1) having a size of 10 cm or less, particularly 1 mm or less in diameter, using an electron sheath, that is, a negative sheath region 2 in a plasma environment in outer space. Is negatively charged, and the altitude of the debris 1c is intentionally lowered by causing the force F of the electric field to act in a direction that decelerates the speed of the charged debris 1c, thereby causing the debris 1c to enter the atmosphere 3.

FIG. 1 is a conceptual diagram showing the principle of the space debris removal apparatus according to the present invention. FIG. 2 shows a conceptual diagram of the charging principle and debris deceleration of the debris 1.
The space environment 6 in the low earth orbit 8 above the earth 4 is a plasma environment. Plasma refers to a state where electrons are separated from atoms and molecules and ions and electrons are mixed.
As shown in FIG. 1, a giant reticulated charged body 5 that can be expanded to 1 km or several km square using an artificial satellite 23 is launched into a space of 400 to 2000 km in low Earth orbit 8 and the reticulated charged body 5 is , Especially in polar orbits. A reticulated electrode 5e is configured by applying a positive voltage to the expanded reticulated charged body 5 using a power supply device 7 such as a solar battery or a storage battery. In order to remove the debris 1 which is space debris from the Earth's low orbit 8, it is necessary to apply a high voltage to the mesh charging body 5 to form the mesh electrode 5e. Since it cannot be applied, it is necessary to apply it in a pulse form here. Further, in order to apply the reticulated charged body 5 to a positive bias, the reticulated charged body 5 is connected to the positive pole of the power supply device 7, but the negative pole of the power supply device 7 is connected to the artificial satellite 23, that is, the artificial satellite 23 is grounded. Use as

  When the net-like charged body 5 is positively charged, the net-like charged body 5 becomes the net-like electrode 5e, and the balance between electrons e and ions in the peripheral region of the net-like electrode 5e is lost, and the net-like electrode 5e attracts the electrons e. As a result, the electrons e dominate around the mesh electrode 5 e to form an electron sheath, that is, a negative sheath region 2. When space debris, that is, debris 1, which is a conductor sphere having no electric charge, jumps into the negative sheath region 2, there is always a potential difference between the conductor surface and the space potential on the left side of the mesh electrode 5 e (FIG. 2). The potential of the debris 1 is determined so that the current collected from the peripheral plasma becomes zero. Since the potential of the conductor surface of the debris 1 sinks negative with respect to the space potential, the debris 1 is negatively charged at once. After the charged debris 1c passes through the mesh electrode 5e, an electric field generated by an electron group accelerated toward the mesh electrode 5e is generated on the right side (FIG. 2), and a force F acts on the electron e in the opposite direction. The negatively charged debris 1c is decelerated because the kinetic energy is canceled out.

  FIG. 3 shows a conceptual diagram in which the charged debris 1c enters the atmosphere. The debris 1 circulates at an altitude of 400 to 600 km at about 10 km / sec. However, the debris 1 is negatively charged by passing through the biased mesh electrode 5e, and the negatively charged debris 1c receives the force F of the electric field. When the kinetic energy is canceled and decelerated, the charged debris 1c descends altitude and enters the atmosphere 3 and is burned out and incinerated by friction with the atmospheric resistance.

Next, a floating potential measurement test was performed in order to verify how many volts the debris 1 was negatively charged with an electronic sheath formed by a mesh electrode 5e to which a voltage was applied in plasma.
A positive potential was applied to the reticulated charged body 5 in the plasma to form a reticulated electrode 5e, and the floating potential in the vicinity thereof was measured. The floating potential is the potential with respect to the outer space of the debris 1, and the voltage at which the current becomes zero is the floating potential. The amount of charge (Q) possessed by debris is determined by the difference between the space potential (V _spece ) and the debris potential (floating potential, V _floating ).
Q = 4πε ₀ a (V _spece -V _floating )
In the floating potential measurement test, the surface potential of the probe 16 can be regarded as the potential of the debris 1 by measuring with the probe 16 and measuring the surface potential of the probe 16 with the surface potential meter 22. It can be called an electric potential measurement test.
The charge density on the surface of the charged debris 1c is σ. Assuming that area is A, it is expressed by Equation 1.

数１の式は，電荷密度の時間変化分とその面積の積が正味の電流値となることを示している。浮遊電位は電流値のバランスで決まり，Ｉ_net ＝０となる時の電位が浮遊電位となる。

Equation 1 shows that the product of the change in charge density over time and its area is the net current value. Floating potential is determined by the balance of the current value, the potential at the time of the I _net = 0 serving as a floating potential.

  Practical plasma includes neutral molecules other than ions and electrons, but also includes atomic molecules in which electrons have moved to the excitation orbit and gas molecules in the ground state. A normal gas is basically an insulator that does not conduct electricity. However, when ionization occurs and a plasma state occurs, free electrons that are not bound to atoms are included, so light electrons that apply voltage move easily and current flows. Flow and conduct electricity. As the temperature of the gas increases, the ionized components increase, and at very high temperatures, most atoms are ionized, resulting in a plasma with a high degree of ionization. Usually, in plasma, a difference in the speed of movement occurs between electrons and ions, and particles that jump out of the plasma have more electrons than ions, so the plasma as a whole has a positive potential. This potential is called a space potential and a plasma potential.

  The space potential varies depending on various conditions of the plasma, but is about several V to 100V. The voltage at which the current becomes 0 is a floating potential, but the plasma is floating at a positive voltage due to the difference in the movement speed of ions and electrons. The electron temperature refers to the temperature corresponding to the energy distribution of electrons in the plasma. In plasma, electrons are accelerated by an electric field, collide with gas particles, and discharge is maintained by the process of knocking out electrons, so the electron temperature and ion temperature may be different. Ion temperature refers to the temperature corresponding to the energy distribution of ions in the plasma. Here, the plasma density is the electron density, ion density, that is, the number of charged particles per unit volume, and varies depending on the measurement method. In the case of the Langmuir probe (16, 21), a plurality of multiply charged ions are present. It will be counted as an ion.

  Next, a surface potential measurement test was performed using a surface potential measuring apparatus as shown in FIGS. In this experiment, a metal plate 20 (reticulated charging body 5 in this case) is arranged in the center of the polar orbit simulation chamber 10, and the influence of the surface potential on the probe 16 placed in front of the metal plate 20 is observed. Here, the net-like charged body 5 as the metal plate 20 is disposed above the XY stage 24 in the polar orbit simulation chamber 10. The net-like charged body 5 is connected to the plus electrode of the power supply device 7 to the limiting resistor 14 and the minus electrode of the power supply device 7 is grounded. In the figure, reference numeral 15 denotes a digital multimeter. When the reticulated charged body 5 is connected to the power supply device 7 so as to be positively biased, the balance between the electrons e and ions in the electrically neutral plasma is lost, and the electrons e are attracted to the reticulated electrode 5e, resulting in a negative sheath. Region 2 is formed. If the probe 16 is present in the negative sheath region 2, it is negatively charged, so the relationship between the magnitude of the bias voltage and the measured potential is verified by experiment. Further, the ions are repelled and cannot enter the sheath region 2. Then, when the probe 16 used for measuring the surface potential is floated when the voltage is applied, the change in the potential is examined, so that the floating potential can be measured.

The polar orbit simulation chamber 10 is a vacuum chamber that can simulate a plasma environment. The polar orbit simulation chamber 10 is made of stainless steel and has a cylindrical shape with a diameter of 1.0 m and a depth of 1.2 m. For the exhaust of the polar orbit simulation chamber 10, a roughing rotary pump was used, and the inside of the polar orbit simulation chamber 10 was set to about 10 ⁻⁵ Pa to 10 ⁻³ Pa. The plasma density and electron temperature in the polar orbit simulation chamber 10 were measured using a spherical probe 21 (Langmuir probe) having a diameter of 3 cm. The polar orbit simulation chamber 10 is formed into a plasma state by a plasma generator 12.

  As an experimental sample, using a metal plate 20 (10 × 10 cm) and a net-like charged body 5 (10 × 10 cm) which is a metal net, the sample is fixed in a vacuum chamber 10 with a fishing line, and the voltage is increased from 0 V to 100 V in steps. The reticulated charged body 5 is positively biased to form a reticulated electrode 5e. At that time, the surface potential is measured from the probe 21 arranged at a distance of 1 cm in front of the metal plate 20. The probe 21 starts from a position 1 cm away from the metal plate 20 and moves away from the metal plate 20 by 1 cm, measures the surface potential of the probe 21 at that point, and observes the change. The surface potential of the probe 21 is measured using the surface potential meter 22. The floating potential can be measured by measuring the surface potential of the probe 21. Further, the plasma environment in the polar orbit simulation chamber 10 is measured by the source meter 17 and the measured value is taken into the personal computer 18. The inside of the polar orbit simulation chamber 10 was photographed from the outside through the window glass by the IR camera 13.

FIG. 6 is a graph showing the results of surface potential measurement. In FIG. 6, the vertical axis represents the measurement potential V at the probe 21, and the horizontal axis represents the measurement distance mm from the metal plate 20 to which a voltage is applied. In FIG. 6, the applied voltages are ◯: 0 V, x: 50 V, ◇: 100 V, □: 150 V, Δ: 200 V. The voltage of the probe 21 gradually increases within 10 mm. When the measurement distance is 10 or more, the voltage gradually decreases and settles to a constant voltage. The settled voltage is thought to be the floating potential in the sheath. Since the space potential is considered to be close to the applied voltage in the vicinity of the reticulated charged body 5, a voltage corresponding to the difference between the space potential and the floating potential is applied to the copper powder, and the space potential is negatively charged. It can be said that Further, the spatial potential increases as the bias to the metal plate 20 is increased. This is because when a positive voltage is applied to the mesh charging body 5 and the voltage is increased, the sheath region 2 is expanded. As the sheath region 2 expands, the amount of electrons attracted from the prime space increases, so that what was originally kept neutral in the plasma space is lost, and the overall number of ions gradually increases. It is thought that it happens to go. Further, in the process of changing the distance of the measurement probe from the mesh charged body 5, it is difficult to see the white mist in the sheath region 2 when it is visually observed just before the mesh charged body 5, or it is visible when it is moved away. The measurement probe that was moved in front of the mesh charged body 5 had a great influence on the sheath environment 2 created by the mesh charged body 5.
From the above, it can be confirmed that the debris 1 is negatively charged by passing through the negative sheath region 2.

-Example-
Next, using a polar orbit simulation chamber (LEO chamber) 10 capable of simulating a low earth orbit plasma environment, a powder charge drop test of copper powder 1P as debris 1 was performed. As shown in FIGS. 7 and 8, the polar orbit simulation chamber 10 is made of stainless steel and has a cylindrical shape with a diameter of 1.0 m and a depth of 1.2 m. To evacuate the polar orbit simulation chamber 10, a turbo molecular pump was used, and the plasma source was operated at a gas flow rate of 0.4 sccm, and the back pressure was reduced to about 1 × 10 ⁻² Pa. The plasma density and electron temperature in the polar orbit simulation chamber 10 were measured using a disk-shaped probe 16 (Langmuir probe) having a diameter of 5 cm provided inside the polar orbit simulation chamber 10.

Copper powder 1P was used as a simulation sample as debris 1. As the copper powder 1P, a particle size of 50 μm was used. Further, as the net-like charged body 5, for example, a metal material such as aluminum, zinc, or iron, a material such as a chargeable synthetic resin, for example, a charge body having a wire diameter of 0.3 mm, is formed on the net-like charged body 5. First, in order to negatively charge the debris 1 made of the copper powder 1P, a positive voltage is applied to the reticulated charging body 5 by the power supply device 7 to form the reticulated electrode 5e, and the debris 1 passes in front of the reticulated electrode 5e. As a result, the debris 1 is charged. It was verified whether or not the charged debris 1c is attracted to the mesh electrode 5e side by the force of the electric field by the mesh electrode 5e to change the trajectory.
In FIG. 9, the copper powder 1P dropped from the funnel-shaped powder dropping device 9 passes through the negative sheath region 2 and is negatively charged, and the descending locus moves as the charged copper powder 1P receives the force of the electric field. Then, the state in which the copper powder 1P is accommodated in the receiving tray 11 partitioned is shown. Here, the tray 11 is divided into 1 to 15 rows. When the copper powder 1P is dropped from the funnel-shaped powder dropping device 9, when no displacement occurs in the copper powder 1P, most of the copper powder 1P is set to fall on the seven rows of trays 11 from the left side.

The experimental method and principle of the powder drop test are as follows.
In the polar orbit simulation chamber 10, a metal net (mesh charged body) having a size of 10 × 10 cm is arranged in the vertical direction so that the net charged body 5 can be biased. Wired through. Copper powder 1P prepared as a sample of debris 1 was dropped by a vibration of a vibration motor 19 from a funnel-shaped powder dropping device 9 installed above the net-like charged body 5. This time, copper powder (particle size: 100 μ) was used as a sample of debris 1 having a particle size of 100 μ. In addition, a U-shaped metal tray 11 is arranged below the net-like charged body 5 as a partition row in order to see the fall distribution from the ratio of the mass of the fall distribution recovered below the net-like charged body 5. . The tray 11 has a size of 1.3 × 7 × 1 (cm) arranged in three rows vertically and fifteen rows horizontally. In the powder dropping device 9, the aluminum plate was bent into the container 9C, the container 9C was attached to a bracket (not shown) fixed to the polar orbit simulation chamber 10, and the copper powder 1P measured with an electronic balance was put into the container 9c. A vibration motor 19 is attached to the container 9C, and the operation of the vibration motor 19 causes the copper powder contained in the container 9c to drop by a certain amount. Due to the vibration of the vibration motor 19, the copper powder 1 </ b> P dropped from the powder dropping device 9 passes through the funnel 9 </ b> R attached to the tip of the container 9 </ b> C and drops to the mesh electrode 5 e of the mesh charger 5. The amount of copper powder 1P placed on the tray 11 was measured with an electronic balance, and the distribution of the falling region of the copper powder 1P was measured.

The evaluation method for the measurement distribution is as follows.
As a measurement result, the amount of the copper powder 1P accumulated in each row of the tray 11 was measured. When examining the change of the distribution, we evaluated it using the normal distribution table. In the graph of FIG. 10 showing the results, the horizontal axis indicates the column number, and the vertical axis indicates the average value of the ratio of each column with respect to the total amount of the collected copper powder. Also, the standard deviation is 1σ, and the error bar is shown in the graph. However, the error bar is not displayed for the number of measurements less than 3. FIG. 10 shows a standard deviation curve of a normal distribution table. In FIG. 10, X: true value, XM: average value, X _i : i-th measured value. Δ is the average error of the average value, γ is the probability error of each measurement, σ is the standard deviation of each measurement, ε _i is the i-th measurement error, and υ is the residual of the i-th measurement value .

1. The measurement results of the comparison by pressure are as follows.
The plasma generator 12 is not operated, that is, the plasma is not ignited and the polar orbit simulation chamber 10 is not in a plasma state, and no voltage is applied to the reticulated charged body 5 without bias. The case of 1.3 Pa (◯ in FIG. 11) was performed 8 times, and the case of 4.0 × 10 ⁻⁴ Pa (□ in FIG. 11) was performed 5 times. The measurement results are shown in FIG.
Although the measurement was performed while changing the pressure, the amount of copper powder in the sixth row was only slightly increased, and it was confirmed that there was no significant difference. In addition, the measurement results were stable with no significant errors. The measurement distribution results by pressure were within the standard deviation σ. Here, the number of measurements was small, but the lower pressure is considered to fall together in the central area. That is, when the inside of the polar orbit simulation chamber 10 is not in a plasma state and there is no bias, most of the copper powder 1P dropped from the powder dropping device 9 falls directly below, and the copper powder 1P has a displacement force. I confirmed that I was not working.

2. The measurement results of the comparison of the presence or absence of the reticulated charged body 5 are as follows.
The case where the net-like charged body 5 was not installed was performed once and compared with the measurement result at a pressure of 1.3 Pa. The measurement results are shown in FIG.
Comparing the case (□ in FIG. 12) where the net-like charged body 5 is not installed with the case (◯ in FIG. 12) where the net-like charged body 5 is installed, the cases where the net-like charged body 5 is not installed are large in the fifth and sixth rows. It was confirmed that the number of columns after the seventh column was slightly decreased in all columns. It can be seen that the area on the left side of the net-like charged body 5 is blocked by the presence of the net-like charged body 5.

3. A comparison between a case where a voltage is applied to the net-like charged body 5 and a case where the voltage is applied to the net-like electrode 5e and a case where the voltage is not applied are as follows.
Due to the relationship between the specifications of the limiting resistor 14 and the power supply device 7, two types of voltages, a 115 V case and a 150 V case, were applied to the mesh charger 5.
The case of applying a positive voltage of 115 V was performed twice, and the case of applying a positive voltage of 150 V was performed three times. Here, the measurement results are shown based on the measurement results in a lower pressure state.
FIG. 13 shows the result of measurement distribution when a positive voltage of 115 V is applied to the net charger 5. In the case of the positive 150V in the net-like charged body 5, the result considered that the electric field dropped was only one out of three times. The cause is considered to be that the reticulated charged body 5 is bent by applying a large voltage of 150 V to the reticulated charged body 5, and the angle is slightly changed. FIG. 14 shows a measurement distribution result when a positive voltage of 150 V is applied to the net-like charged body 5.
As can be seen from FIG. 13 and FIG. 14, it can be seen that there is a difference in the sixth column between when the voltage is applied to the mesh charger 5 and when no voltage is applied to the mesh charger 5. This is because, when a voltage is applied to make the net-like charged body 5 the net-like electrode 5e and the negative sheath region 2 is formed in the vicinity thereof, if the copper powder 1P is passed through the negative sheath region 2, It was confirmed that the copper powder 1P moved by displacing the dropping direction by force.
That is, the amount of the sixth row of the section of the tray 11 is increased, and the seventh and eighth rows are slightly decreased. The decrease in the 7th and 8th rows is thought to have moved to the 6th row, which is thought to be because the copper powder was negatively charged and the trajectory of falling due to the electric field force changed. There was no significant difference for the other columns. In both cases of 115V and 150V, the error bar exceeds the standard deviation σ, which is 3σ with a probability of 99.73%, and can be evaluated as clearly changing.
Further, in the case of the higher voltage of 150V, the difference in the sixth voltage column appears more prominently than in the case of 115V. It was confirmed that the charge amount of the copper powder 1P can be expressed by Q = 4πε ₀ aV, the charge amount is proportional to the magnitude of the voltage, and further the electric field force is proportional to the voltage situation.

4). The case where no voltage is applied during plasma ignition is as follows.
The case where no voltage was applied with the plasma ignited was performed once. The measurement results are shown in FIG.
Compared to when the plasma was not ignited and no voltage was applied, a slight increase in the sixth row was observed, but the change was not as great as when the voltage was applied.

The estimation of the charge amount from the moving distance of the copper powder 1P is as follows.
In the above-described embodiment, it is considered that the decrease in the seventh column appears as the increase in the sixth column from the comparison between the seventh column and the sixth column before and after the voltage application. Here, the charge amount in the case of a moving distance of 1.3 cm, which is a shift for one row, was estimated from the moving distance of the copper powder 1P.

Summarizing the above copper powder drop test, the following conclusions can be obtained.
A voltage is applied to the net-like charged body 5 by the power supply device 7, and the net-like charged body 5 can be formed on the net-like electrode 5e. The debris 1 can be negatively charged by passing the copper powder 1P that becomes the debris 1 through the sheath formed by the mesh electrode 5e. It was confirmed that the negatively charged debris 1c was attracted to the mesh electrode 5e by the electric field force of the mesh electrode 5e, and the trajectory could be changed.

In this space debris removal method and apparatus, the number of debris that can be removed in one year is 10,000 km per year assuming that the diameter of the debris 1 is 100 μm when the network charged body 5 of 1 km ² is arranged at an altitude of 400 km. It was found that it is possible to incinerate individual pieces.

  The method and apparatus for removing space debris according to the present invention can be applied to a method and apparatus for removing space debris floating in outer space. Necessary equipment for achieving the present invention, for example, a charged net, an artificial satellite, a power source, etc. It can be applied in the industrial field of manufacturing equipment such as devices.

It is a conceptual diagram which shows the principle of the space debris removal apparatus by this invention. It is a conceptual diagram of the debris charging principle and debris deceleration. It is a conceptual diagram of the entry of debris into the atmosphere. It is the schematic which shows a surface potential measuring apparatus. It is a schematic explanatory drawing which shows arrangement | positioning in a polar orbit simulation chamber. It is a graph which shows a surface potential measurement result. It is the schematic which experimented using the polar orbit simulation chamber which simulated the space debris removal apparatus by this invention. It is a schematic explanatory drawing which shows the layout in a polar orbit simulation chamber. It is the schematic which shows the relationship between the funnel-shaped powder dropping apparatus, the copper powder which is a debris, a negative sheath area | region, and a division tray. It is a graph which shows a standard deviation curve. It is a graph which shows the measurement result of the fall field of copper powder according to pressure. It is a graph which shows the measurement result of the fall area | region of the copper powder by the presence or absence of arrangement | positioning of a net-like charged body. It is a graph which shows the measurement result of the fall area | region of the copper powder in the case where the voltage of 115V is applied to the net-like charged body, and the case where it is not applied. It is a graph which shows the measurement result of the fall area | region of the copper powder in the case where the voltage of 150V is applied to the net-like charged body, and the case where it is not applied. It is a graph which shows the measurement result of the fall area | region of the copper powder in the case where a voltage is not applied at the time of plasma ignition.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Debris 1c Charged debris 2 Negative sheath area | region 3 Atmosphere 4 The earth 5 Reticulated charged object 5e Reticulated electrode 7 Power supply device 8 Low earth orbit 23 Artificial satellite e Electron F Electric field force

Claims (8)

A reticulated charged body is expanded and arranged in a vacuum plasma existing in a low earth orbit, and the reticulated charged body is positively biased to form a reticulated electrode, and the reticulated electrode is formed by accelerated electrons around the reticulated electrode. The space debris of fine particles flying around the space is negatively charged, the space debris is decelerated by the force of the electric field of the mesh electrode, the orbit of the space debris is lowered, and the space debris enters the atmosphere and is incinerated. A method for removing space debris. 2. The space debris removal method according to claim 1, wherein an electron sheath is formed around the positively biased mesh electrode, and the space debris flying into the electron sheath is negatively charged. . The space debris removal method according to claim 1 or 2, wherein the net-like charged body is applied to the net-like electrode by being applied in pulses in the plasma. The space debris removal method according to any one of claims 1 to 3, wherein the space debris are fine particles of 1 mm or less. Reticulated charged body spread in vacuum plasma existing in low earth orbit, power supply apparatus for connecting and applying voltage to reticulated charged body for positively biasing reticulated charged body with respect to plasma potential, and said power supply apparatus An artificial satellite for grounding the power supply device and energizing the power supply device to positively bias the mesh charged body to form a mesh electrode, forming an electronic sheath around the mesh electrode, The space debris of fine particles flying into the electronic sheath is negatively charged, the negatively charged space debris is decelerated by the force of the electric field of the mesh electrode, the trajectory is lowered, and the space debris enters the atmosphere. Space debris removal device characterized by incineration. 6. The space debris removal apparatus according to claim 5, wherein the net-like charged body is applied to the net-like electrode by being applied in pulses in the plasma. The space debris removal apparatus according to claim 5 or 6, wherein the space debris is fine particles of 1 mm or less. The net-like charged body is launched into the Earth's low orbit by the artificial satellite and is expanded to 1 km to several km square in the earth's low orbit. Space debris removal device.

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