JP2022143395A - Speed reducer - Google Patents

Abstract

To provide a speed reducer having a film member, which adjusts a deceleration rate of an object that moves in a cosmic space by controlling a posture of the film member.SOLUTION: A speed reducer 1 can adjust a deceleration rate of an object 2 that moves in a cosmic space. The speed reducer 1 comprises a film member 20, a charging device 30 and a control device 11. The film member 20 is attached to the object 2 or constitutes a portion of the object 2, which has a first surface 20a including a plurality of electrically separated regions R. The charging device 30 is electrically connected to the film member 20 to charge the plurality of regions R respectively. The control device 11 controls each voltage applied by the charging device 30 to the plurality of regions R.SELECTED DRAWING: Figure 1

Description

The present invention relates to a deceleration device capable of adjusting the deceleration rate of an object moving in outer space.

There are various needs for adjusting the deceleration rate of a moving object in space. For example, such needs are found in the removal of space junk, referred to as space debris, and the control of satellites or planetary probes. As for space debris, there are many in orbit around the earth, and it is required to decelerate the space debris and move it out of the important satellite orbit that should be protected.

Patent Literature 1 discloses a space debris reduction device that decelerates space debris. This space debris mitigation device has a drag augmentation device comprising a circular or polygonal membrane member or a balloon or air mat-like structure capable of enclosing gas pressure. This space debris mitigation device is attached to the space debris and receives a small amount of atmospheric and solar radiation pressure from the drag augmentation device to decelerate the space debris and change its trajectory. Space debris is thus kept out of critical satellite orbits to be protected.

JP 2010-285137 A

Atmospheric density decreases significantly with increasing orbital altitude. For example, it has been confirmed that the atmospheric density drops to about 1/50 to 1/100 at an altitude of around 1000 km compared to that at an altitude of 400 km to 600 km. Therefore, in the space debris mitigation device of Patent Document 1, as the orbital altitude increases, the drag obtained from the atmosphere decreases, and there is a possibility that sufficient execution performance cannot be obtained.

In the region of orbital altitude where the atmospheric density is not sufficient as described above, there are electrically neutral gas and ionized gas (ions and electrons) partially ionized by solar ultraviolet rays. Therefore, a closer look at changes in atmospheric density reveals that the density of the neutral atmosphere decreases markedly with increasing altitude as described above, while the density of ions decreases less. In other words, in regions of orbital altitude where the atmospheric density is not sufficient, it may be more effective to receive drag from ions than to receive drag from neutral atmosphere. For that purpose, for example, the membrane member of Patent Document 1 is charged to form a sheath (an electrically non-neutral space charge layer having a potential gradient) around the membrane member, and the sheath is used to reduce the drag force from the ions. can be considered to increase

However, even when the sheath is used to increase the drag from the ions, there is a possibility that sufficient drag from the ions cannot be obtained depending on the orientation of the membrane member. Specifically, as the posture of the membrane member becomes parallel to the traveling direction, the pressure receiving area from the ions decreases, and there is a possibility that sufficient drag cannot be obtained. Therefore, it is required to suitably control the posture of the membrane member, but no specific method has been established.

SUMMARY OF THE INVENTION An object of the present invention is to adjust the deceleration rate of an object moving in outer space by controlling the attitude of the film member in a reduction gear transmission having a film member.

The present invention
A deceleration device capable of adjusting the deceleration rate of an object moving in outer space,
a membrane member attached to or forming part of the object and having a first surface including a plurality of electrically isolated regions;
a charging device electrically connected to the film member and charging each of the plurality of regions;
and a control device for controlling the voltage applied to each of the plurality of regions by the charging device.

According to this configuration, by adjusting the voltage applied to each of the plurality of regions of the membrane member, it is possible to adjust the drag force that each of the plurality of regions of the membrane member receives from the ions. Therefore, the attitude of the membrane member can be controlled. By controlling the posture of the film member, the deceleration rate of the object can be adjusted. Here, the object broadly means something that moves in outer space, and can be, for example, space debris, an artificial satellite, or a planetary probe.

The film member may have a plurality of film pieces forming each of the plurality of regions.

According to this configuration, since each of the plurality of film pieces is structurally separated from each other, even if some of the plurality of film pieces are damaged, the others are damaged along with it, and the entire structure fails to function. can be suppressed.

The deceleration device further includes an orientation detection device that detects the orientation of the film member,
The control device may control the charging device according to the attitude of the film member detected by the attitude detection device.

According to this configuration, the posture of the membrane member can be preferably controlled. Specifically, by controlling the voltage application position on the first surface and the applied voltage, the “position where force is generated” and the “magnitude of force” received from the ion flow are varied, and the torque with respect to the center of gravity of the first surface is changed. It is possible to control the attitude of the membrane member. Further, by accumulating the control over time, the total torque that the first surface receives from the ion flow can be controlled. For example, if the orientation of the first surface of the membrane member is not perpendicular to the direction of travel, the orientation of the first surface of the membrane member may be controlled to be perpendicular to the direction of travel. As a result, the drag force that the film member receives from the ions can be increased, and the deceleration rate of the object can be increased. Further, when the orientation of the first surface of the membrane member is nearly perpendicular to the direction of travel, the orientation of the first surface of the membrane member may be controlled to be parallel to the direction of travel. As a result, the drag force that the membrane member receives from the ions can be reduced, and the deceleration rate of the object can be reduced.

The membrane member has the first surface and a second surface opposite to the first surface,
The charging device is capable of charging the first surface and the second surface to different potentials,
The control device may control the charging device to charge the first surface to a negative potential lower than the second surface by a predetermined potential difference.

According to this configuration, since a predetermined potential difference is provided between the first surface and the second surface of the membrane member, isotropic formation of the sheath around the membrane member can be suppressed. Here, the first surface is arranged as a surface on the upstream side of the ion flow (surface on the pressure receiving side), and the second surface is arranged as a surface on the downstream side of the ion flow. As a result, ions can be efficiently collected on the first surface, and ions can be prevented from straying to the second surface. Therefore, the momentum exchange of ions with respect to the membrane member can be suppressed from canceling out on the upstream side (first surface side) and the downstream side (second surface side) of the ion flow, and sufficient drag can be obtained from the ions. . Here, the predetermined potential difference is a value that can effectively suppress the ions from entering the second surface. For example, the predetermined potential difference may be between 10V and 1000V. Also, the negative potential may be a potential relative to a reference potential in outer space. In outer space, for ease of measurement and setting, the potential of the speed reducer (for example, the satellite body) itself may be used as a reference potential, and a potential that is relatively negative with respect to the reference potential may be treated as a negative potential.

The membrane member is
a first conductor made of a conductive material forming the first surface;
a second conductor made of a conductive material forming the second surface;
a third conductor made of a conductive material disposed between the first conductor and the second conductor;
a first non-conductor made of an insulating material or a dielectric material disposed between the first conductor and the third conductor;
and a second non-conductor made of an insulating material or a dielectric material interposed between the second conductor and the third conductor.

According to this configuration, the membrane member has a five-layer structure, and specifically, a predetermined potential difference can be provided between the first surface and the second surface. In particular, by arranging the third conductor in the center, it is possible to accurately apply a potential difference from the third conductor to the first conductor and the second conductor.

The membrane member is
a first conductor made of a conductive material forming the first surface;
a second conductor made of a conductive material forming the second surface;
and a non-conductor made of an insulating or dielectric material interposed between the first conductor and the second conductor.

According to this configuration, the membrane member has a three-layer structure, and specifically, a predetermined potential difference can be provided between the first surface and the second surface. Generally, it is assumed that the membrane member is stored in a folded state until it is deployed in outer space. At the time of storage, since the number of electrical connections and wiring increases as the number of layers of the film member increases, there is a possibility that it will be difficult to handle to prevent problems with the connections and wiring. Therefore, it is effective to simplify the structure and facilitate handling by configuring the membrane member in three layers.

The control device may control the charging device to charge each of the plurality of regions to a positive potential.

According to this configuration, since each of the plurality of regions is charged to a positive potential, it is possible to receive a drag force from the ions by repelling the ions with the membrane member. Here, the positive potential can be a potential relative to the reference potential in outer space, as described above.

According to the present invention, in a deceleration device having a film member, the deceleration rate of an object moving in outer space can be adjusted by controlling the posture of the film member.

1 is a schematic configuration diagram of a reduction gear transmission according to a first embodiment of the present invention; FIG. The front view of a satellite main body and a film|membrane member. The front view which shows the modification of the satellite main body of FIG. 2, and a film|membrane member. FIG. 2 is a front view of a membrane member showing multiple regions; The side view of the film|membrane member which shows attitude|position control. FIG. 4 is a front view of a film member showing attitude control; FIG. 11 is a perspective view of a film member showing another attitude control; FIG. 11 is a front view of a membrane member showing another attitude control; FIG. 10 is a first side view of the film member showing attitude control when the film member rotates; FIG. 11 is a second side view of the film member showing attitude control when the film member rotates; Sectional drawing which shows the modification of a film|membrane member. FIG. 4 is a schematic diagram showing a sheath around a membrane member having a single-layer structure; FIG. 4 is a schematic diagram showing a sheath around a film member having a multilayer structure; FIG. 12 is a cross-sectional view showing a modification of the film member of FIG. 11; FIG. 12 is a cross-sectional view showing another modification of the film member of FIG. 11; FIG. 2 is a schematic configuration diagram when a reduction gear is installed in front of an object in its traveling direction; The schematic block diagram of the reduction gear transmission which concerns on 2nd Embodiment. The side view of the target object which shows the modification of the reduction gear transmission which concerns on 2nd Embodiment. FIG. 4 is a schematic diagram showing a sheath when the membrane member is charged to a positive potential; The front view which shows the modification of a film|membrane member. The side view which shows the modification of a film|membrane member.

Embodiments of the present invention will be described below with reference to the accompanying drawings.

(First embodiment)
FIG. 1 is a schematic configuration diagram of a reduction gear transmission 1 according to a first embodiment of the present invention.

A deceleration device 1 of this embodiment is attached to space debris 2 (an example of an object moving in outer space) orbiting the earth, and adjusts the deceleration rate of the space debris 2 . For example, the trajectory of the space debris 2 can be changed by reducing the circulating speed of the space debris 2 with the speed reducer 1 . As a result, important orbits used for artificial satellites can be protected by, for example, dropping the space debris 2 to the ground. In addition, since the position of space debris on the earth orbit is generally known, if the space debris 2 attached with the reduction gear 1 is likely to collide with other space debris, the deceleration rate is adjusted to avoid collision. can also As a result, it is possible to prevent the space debris 2 from turning into a plurality of small pieces and becoming difficult to remove.

In FIG. 1, the traveling direction of the space debris 2 is indicated by an arrow A1. When viewed from the reduction gear 1, the ion current relatively flows in the direction opposite to the arrow A1. Also, a portion of the reduction gear transmission 1 indicated by a dashed circle is shown enlarged.

The reduction gear 1 of this embodiment includes a satellite body 10 , a film member 20 , a charging device 30 and a mounting device 40 .

FIG. 2 is a front view of the satellite body 10 and the membrane member 20. FIG.

The satellite body 10 has a propulsion function. Although not described in detail, the propulsion function may be accomplished by known mechanisms such as ion engines. The satellite body 10 is directly connected to the membrane member 20, and the relative positional relationship between the satellite body 10 and the membrane member 20 is fixed. Further, the satellite main body 10 is equipped with a control device 11 (see FIG. 1) for controlling the charging device 30 as will be described later in detail.

The film member 20 is in the form of a thin film. In this embodiment, the membrane member 20 is square when viewed from the front. The membrane member 20 has a first surface 20a that serves as a pressure receiving surface from the ion flow, and a second surface 20b opposite to the first surface 20a. The membrane member 20 has a frame 21 provided along the diagonal of the square. The frame 21 maintains the deployed state of the membrane member 20 and can efficiently receive pressure from the ion flow. The frame 21 has a foldable structure and may be in a folded state before the membrane member 20 is deployed. Note that the shape of the film member 20 is not particularly limited to a square, and may be any shape.

FIG. 3 is a front view showing a modification of the satellite body 10 and membrane member 20 of FIG.

The connection mode between the satellite body 10 and the membrane member 20 is not limited to that shown in FIG. The support member 22 is a columnar member having a predetermined length. By maintaining a predetermined distance between the satellite body 10 and the membrane member 20 by the support member 22, a large area for the membrane member 20 to receive pressure from the ions can be ensured.

Referring to FIG. 1, charging device 30 includes a power source 31 for applying voltage, electrical wiring, and the like. The power supply 31 is electrically connected to the film member 20 via electrical wiring. The charging device 30 can charge each of the plurality of regions R provided on the first surface 20a of the film member 20 to different potentials, as will be described later. Alternatively, power supply 31 may be replaced by an ion source with similar charging capabilities.

The mounting device 40 has a trapping mechanism 41 for trapping the space debris 2 .

The capturing mechanism 41 includes a gripping portion 41a that grips the space debris 2, an injection device 41b that ejects the gripping portion 41a so as to grip the space debris 2, and a tether of a predetermined length that connects the gripping portion 41a and the injection device 41b. 41c. Such a capture mechanism 41 is specific to ADR (Active Debris Removal) that removes space debris already in earth orbit. PMD (Post Mission Disposal), which is the self-disengagement of a satellite or rocket that has completed its operation from its orbit, will be described in the second embodiment.

The reduction gear 1 having the above configuration approaches the space debris 2 by the propulsion function of the satellite body 10, ejects the grasping part 41a with the tether 41c from the ejection device 41b, and grasps and captures the space debris 2. Next, the trajectory of the space debris 2 is changed by deploying the membrane member 20 and reducing the circulating speed of the space debris 2 . Therefore, it can be said that the reduction gear transmission 1 of the present embodiment is compatible with ADR.

Behind the large-sized space debris 2, a space (ion wake) is generated in which the ratio of ions having relatively low thermal velocities with respect to the orbital velocity of the space debris decreases as the distance to the space debris 2 increases. If the membrane member 20 is positioned in this ion wake region, the ion collection capability of the membrane member 20 may decrease. Therefore, the tether 41c must have a predetermined length in order to prevent the membrane member 20 from being positioned in the ion wake region. For example, the space debris 2 is assumed to be the upper stage of a rocket that has completed its operation. In that case, the upper stage of the rocket is about 2m to 4m in diameter, the orbital velocity at an altitude of 700 to 1000km is about 7.5km/s, and the thermal velocity of oxygen ions, which have a large momentum, is about 1.1km/s. Therefore, the predetermined length is assumed to be 10 to 20 m, preferably about 30 m.

Although the capture mechanism 41 includes the grasping portion 41a in this embodiment, the capturing mode of the capturing mechanism 41 is not limited to using the grasping portion 41a. Also, the tether 41c does not have to be in the form of a flexible string, and may be a structure having a certain degree of rigidity, for example.

FIG. 4 is a front view of the film member 20 showing multiple regions R. FIG. For clarity of illustration, the reference numerals 23, 32, 33 and the reference R are only partially applied. This also applies to subsequent figures. Moreover, in FIG. 4, a portion of the film member 20 indicated by a two-dot chain line circle is shown in an enlarged manner.

The first surface 20a of the membrane member 20 includes a plurality of electrically isolated regions R. As shown in FIG. In this embodiment, the film member 20 has a plurality of film pieces 23 that respectively configure the plurality of regions R on the first surface 20a. A plurality of film pieces 23 are held by a thin insulating sheet 24 having insulating properties. In the illustrated example, a plurality of film pieces 23 constitute a first surface 20a serving as a pressure receiving surface and a second surface 20b opposite to the first surface 20a (see FIG. 1). That is, the plurality of film pieces 23 are arranged so as to penetrate the insulating sheet 24 . The plurality of film pieces 23 has a conductor surface that forms the first surface 20a and a conductor surface that forms the second surface 20b, and can be applied to different potentials. Details will be described later with reference to FIGS. ) may be wired so that they can be applied to different potentials. Also, the distance d between each of the plurality of film pieces 23 (that is, the width d of the insulating portion) is designed to the extent that creeping discharge can be prevented. Each of the plurality of membrane pieces 23 may be connected by sewing the insulating sheet 24 as shown, or may be connected using an insulating adhesive.

In this embodiment, the plurality of film pieces 23 are composed of a total of 81 film pieces, ie, 9 vertical×9 horizontal film pieces in FIG. However, the number and arrangement of film pieces constituting the plurality of film pieces 23 are not particularly limited. Further, in this embodiment, each of the plurality of film pieces 23 is square. However, the shape of each of the plurality of membrane pieces 23 is not particularly limited as long as it can receive pressure from the ion flow. Although the film member 20 has a plurality of film pieces 23 in this embodiment, the film member 20 may be made of one film. In this case, multiple regions R are electrically separated on one film.

Each of the multiple film pieces 23 (that is, multiple regions R) is charged by the charging device 30 . In the illustrated example, a main hot line 32 (see dashed line) and a sub-hot line 33 (see dashed line) are attached as electrical wiring to each of the plurality of film pieces 23 . Main hot line 32 and sub hot line 33 are electrically connected to charging device 30 . That is, each of the plurality of film pieces 23 can be charged to different potentials through the main hot line 32 (see dashed line) and sub-hot line 33 (see dashed line). The power supply structure is an example of a redundant system design that configures a plurality of film pieces 23, and other structures or structures other than the redundant system design may be employed.

The control device 11 controls the voltage applied to each of the plurality of film pieces 23 (that is, the plurality of regions R) by the charging device 30 . The control device 11 includes hardware such as a CPU (Central Processing Unit), RAM (Random Access Memory), and ROM (Read Only Memory), and software installed therein.

In this embodiment, an orientation detection device 12 is provided to detect the orientation of the film member 20 . The orientation detection device 12 may be a known angle detector such as a gyro sensor. In this embodiment, the attitude detection device 12 is mounted on the satellite body 10 . Since the satellite body 10 and the membrane member 20 are rigidly connected directly or via the support member 22, the attitude of the membrane member 20 can be detected by detecting the attitude of the satellite body 10. FIG. Alternatively, the attitude detection device 12 may be attached directly to the membrane member 20 . Also, the attitude detection device 12 is not an essential component and can be omitted as necessary.

FIG. 5 is a side view of the film member 20 showing attitude control. FIG. 6 is a front view of the film member 20 showing attitude control. 5 and 6, the X axis indicates an axis perpendicular to the first surface 20a, and the Y and Z axes indicate axes perpendicular to the X axis, parallel to each side of the square of the film member 20, and perpendicular to each other. ing. This also applies to subsequent figures.

1, 5, and 6, the control device 11 controls the charging device 30 according to the attitude of the film member 20 detected by the attitude detection device 12. FIG. In this embodiment, the posture of the membrane member 20 with respect to the ion flow A2 is preferably controlled. The ion flow A2 indicates ions flowing in the direction opposite to the traveling direction A1 of the space debris 2 (see FIG. 1).

In the examples of FIGS. 5 and 6, the membrane member 20 is not arranged perpendicularly to the ion flow A2, but is inclined around the Z-axis with respect to the ion flow A2. In such a case, among the plurality of regions R, the negative potential is applied to the region positioned upstream of the ion flow A2, and not applied to the other regions. In the illustrated example, the negative potential is applied to the nine regions located on the most upstream side (see hatched areas), and is not applied to the other regions among the plurality of regions R. FIG. A positive potential is applied to the entire second surface 20b. Ions are collected in a negatively charged area (see shaded area), and the membrane member 20 receives a strong pressure and drag force from the ions in this area (see shaded area). As a result, a rotational force around the Z-axis is generated in the membrane member 20 (see arrow A3), and the membrane member 20 can be arranged perpendicular to the ion flow A2. After that, the control device 11 cancels the application. At this time, since the membrane member 20 and the satellite main body 10 are rigidly connected, not only the membrane member 20 but also the satellite main body 10 can be arranged perpendicular to the ion flow A2.

FIG. 7 is a perspective view of the film member 20 showing another attitude control. Also, FIG. 8 is a front view of the film member 20 showing another posture control.

In the examples of FIGS. 7 and 8, the membrane member 20 is not arranged perpendicularly to the ion flow A2, but is inclined around the Y-axis and the Z-axis. In such a case, as shown in FIG. 8, a negative potential is applied to 24 regions (see shaded areas) located upstream of the ion flow A2 among the plurality of regions R, and the other regions are is not applied. A positive potential is applied to the entire second surface 20b. As a result, in the same manner as described above, strong pressure is received from the ions in the region (see the shaded area), and the membrane member 20 receives a drag force, and a rotational force around the Y-axis and the Z-axis is generated in the membrane member 20 (see arrow A3). 20 can be arranged perpendicular to the ion flow A2.

FIG. 9 is a first side view of the film member 20 showing attitude control when the film member 20 rotates. FIG. 10 is a second side view of the film member 20 showing attitude control when the film member 20 rotates, and shows a state after a certain period of time has elapsed from FIG.

In the examples of FIGS. 9 and 10, the film member 20 is rotating around the Z axis (see arrow A4). In this case, the first surface 20a on the front side with respect to the rotation direction A4 is charged to a negative potential, and the second surface 20b on the rear side is charged to a positive potential. In particular, in the illustrated example, of the plurality of regions R of the first surface 20a, only the region located at one end in the Y direction (see hatched portion) is charged to a negative potential. The second surface 20b charges the whole to a positive potential. As a result, in the same region (see hatched area) as described above, strong pressure is received from the ions and drag force is applied, and a rotational force around the Z axis is generated in the membrane member 20 (see arrow A3), causing the membrane member 20 to rotate. can be weakened and finally the membrane member 20 can be arranged perpendicular to the ion flow A2. At this time, since the membrane member 20 and the satellite main body 10 are rigidly connected, not only the membrane member 20 but also the satellite main body 10 can be arranged perpendicular to the ion flow A2.

According to the reduction gear transmission 1 of this embodiment, the following effects are obtained.

By adjusting the voltage applied to each of the plurality of regions R of the membrane member 20, the drag force that each of the plurality of regions R of the membrane member 20 receives from the ions can be adjusted. Therefore, the posture of the film member 20 can be controlled. By controlling the posture of the film member 20, the deceleration rate of the space debris 2 can be adjusted.

In addition, since the film member 20 has a plurality of film pieces 23, and each of the plurality of film pieces 23 is structurally separated from each other, even if some of the plurality of film pieces 23 are damaged, the others are damaged. can be suppressed from being damaged and not functioning as a whole. Alternatively, the multiple regions R may be electrically separated but not structurally separated. For example, a single sheet may be provided with a plurality of conductive regions R and insulating regions so as to electrically separate the plurality of regions R from each other.

In addition, since the reduction gear transmission 1 has the posture detection device 12, the posture of the film member 20 can be preferably controlled. Specifically, by controlling the voltage application position and the applied voltage on the first surface 20a, the "force generation position" and "force magnitude" received from the ion flow A2 are varied, and the center of gravity of the first surface 20a is changed. can be controlled to control the attitude of the film member 20 . Further, by accumulating the control over time, the total torque that the first surface 20a receives from the ion flow A2 can be controlled. 5 to 10, the attitude control for arranging the membrane member 20 perpendicularly to the ion flow A2 has been described as an example. Attitude control for placement can also be realized. Furthermore, the attitude of the membrane member 20 with respect to the ion flow A2 is not limited to vertical or parallel, and can be controlled to any attitude such as an inclined attitude. Therefore, the deceleration rate of the space debris 2 can be easily adjusted according to the posture of the film member 20 .

FIG. 11 is a cross-sectional view showing a modification of the membrane member 20. As shown in FIG.

In this modified example, unlike the above-described embodiment, the insulating sheet 24 (see FIG. 4) is not provided, and each of the plurality of film pieces 23 has a multilayer structure and is connected to each other. The film member 20 has a first surface 20a and a second surface 20b opposite to the first surface 20a, as described above. Since the insulating sheet 24 (see FIG. 4) is not provided, not only the first surface 20a but also the second surface 20b are composed of a plurality of film pieces 23. FIG. Note that FIG. 11 schematically shows one of the plurality of film pieces 23 .

The film member 20 of this modified example has a structure that can be charged to a plurality of potentials on the first surface 20a and the second surface 20b. That is, the first surface 20 a and the second surface 20 b can be charged to different potentials by the charging device 30 .

The film member 20 of this modification includes a first conductor 23a made of a conductive material forming a first surface 20a, a second conductor 23b made of a conductive material forming a second surface 20b, and a first conductor A third conductor 23c made of an electrically conductive material is provided between 23a and the second conductor 23b. In addition, the film member 20 includes a first non-conductor 23d made of an insulating material or a dielectric material arranged between the first conductor 23a and the third conductor 23c, and a conductor between the second conductor 23b and the third conductor 23c. and a second non-conductor 23e of insulating or dielectric material disposed therebetween. In this embodiment, both the first nonconductor 23d and the second nonconductor 23e are made of polyimide. However, the material of the first nonconductor 23d and the second nonconductor 23e is not particularly limited as long as it is an insulator material or a dielectric material.

In this modification, the negative electrode of the power source 31 is electrically connected to the first conductor 23a, and the positive electrode of the power source 31 is electrically connected to the second conductor 23b. The third conductor 23 c is connected to the ground portion 10 , which indicates that the third conductor 23 c is electrically connected to the satellite body 10 . Therefore, here, the grounding portion 10 and the satellite body 10 are indicated by the same reference numerals. In outer space, the potential of the satellite body 10 is not necessarily zero, and the potential of the satellite body 10 fluctuates depending on the surrounding environment of the satellite body 10 . Therefore, the potential of the ground portion 10 indicates the so-called spacecraft potential (reference potential) at the position where the satellite body 10 exists. In this embodiment, the charging device 30 charges the first surface 20a to a negative potential lower than the second surface 20b by a predetermined potential difference. A negative potential here can be a potential relative to the reference potential.

The predetermined potential difference between the first conductor 23a (first surface 20a) and the second conductor 23b (second surface 20b) is preferably set to 10V to 1000V, more preferably 100V to 1000V. is set. Also, preferably, the potential of the first conductor 23a (first surface 20a) is set to −10 V or less (higher on the negative side), more preferably −100 V or less (higher on the negative side). Note that the potential of -10 V or less or -100 V or less here is a potential based on the spacecraft potential. According to the potential difference and the electric potential, it is possible to suppress isotropic formation of the sheath around the membrane member 20 and to form a sheath capable of efficiently collecting ions on the first surface 20a. Also, the ions can be sufficiently electrostatically accelerated within the sheath. In other words, if the potential difference is less than 10 V, a sheath large enough to efficiently collect ions cannot be formed on the first surface 20a. ), the ions are electrostatically accelerated within the sheath, but the acceleration is not sufficient. If the potential difference is 1000 V or more, the electron or ion current flowing into the film surface consumes a large amount of power, and the present system may become inefficient in terms of power consumption. Also, the applicable physical upper limit voltage may be designed based on the dielectric breakdown voltage of the first nonconductor 23d and the second nonconductor 23e.

The difference between the film member 200 having a single-layer structure and the film member 20 having a multi-layer structure will be described with reference to FIGS.

FIG. 12 shows the shape of the sheath Sm when using a film member 200 having a single-layer structure different from that of this modified example (see FIG. 11). FIG. 13 shows the shape of the sheath Sm when using the membrane member 20 having the same multi-layer structure as in this modified example (see FIG. 11). A sheath Sm indicates an area for collecting ions.

Referring to FIG. 12 , in single-layer structure membrane member 200 , sheath Sm is isotropically (generally spherical) formed around membrane member 200 . In such an isotropic sheath Sm, ions are collected not only on the first surface 200a but also on the second surface 200b opposite to the first surface 200a. As a result, the ion flow A2 wraps around, and the momentum exchange of ions cancels out on the upstream side (first surface 20a side) and downstream side (second surface 20b side) of the ion flow A2. There is a risk that the drag force received will be reduced.

Referring to FIG. 13, in membrane member 20 having a multilayer structure, sheath Sm (in this case, an ion sheath) that effectively contributes to ion collection is formed only on the first surface 20a side. In other words, the sheath at the second surface 20b would be greatly reduced from the state of FIG. 12 and would not effectively contribute to ion collection if the potential of the second surface 20b was equal to the space potential. Therefore, the momentum exchange of ions can be suppressed from canceling out on the upstream side (first surface 20a side) and downstream side (second surface 20b side) of the ion flow A2, and ions are collected only on the first surface 20a. , and can receive drag only at the first surface 20a. In FIG. 13, the dashed line also indicates the region Sp (the electronic sheath in this case) based on the positive potential of the second surface 20b. In the region Sp, collection of ions is suppressed, that is, wraparound of the ion flow A2 is suppressed.

According to this modification, the film member 20 is configured with a five-layer structure, and specifically, a predetermined potential difference can be provided between the first surface 20a and the second surface 20b. In particular, by arranging the third conductor 23c in the center, a potential difference from the third conductor 23c can be accurately applied to the first conductor 23a and the second conductor 23b.

FIG. 14 is a cross-sectional view showing a modification of the film member 20 of FIG. 11. As shown in FIG. In FIG. 14, one of the plurality of film pieces 23 is schematically shown.

In this modified example, the film member 20 is not provided with an insulating sheet, and the plurality of film pieces 23 each have a multilayer structure and are connected to each other. The film member 20 has a first surface 20a and a second surface 20b opposite to the first surface 20a. Since no insulating sheet is provided in this modified example, not only the first surface 20a but also the second surface 20b are composed of a plurality of film pieces 23. FIG.

The film member 20 of this modified example has a structure that can be charged to a plurality of potentials on the first surface 20a and the second surface 20b. That is, the first surface 20 a and the second surface 20 b can be charged to different potentials by the charging device 30 .

The film member 20 includes a first conductor 23f made of a conductive material forming a first surface 20a, a second conductor 23g made of a conductive material forming a second surface 20b, the first conductor 23f and the second conductor 23f. and a non-conductor 23h made of an insulating or dielectric material interposed with the conductor 23g. In this modified example, the nonconductor 23h is made of polyimide. However, the material of the nonconductor 23h is not particularly limited as long as it is an insulator material or a dielectric material.

In the charging device 30, the negative electrode of the power source 31 is electrically connected to the first conductor 23f, and the positive electrode of the power source 31 is electrically connected to the second conductor 23g. In FIG. 14, the first conductor 23f and the second conductor 23g are not electrically connected to the ground portion (satellite body) 10, but the second conductor 23g is grounded as in another modification shown in FIG. It may be electrically connected to the unit (satellite body) 10 . In either case, the charging device 30 can charge the first surface 20a to a negative potential lower than the second surface 20b by a predetermined potential difference. As a result, the film member 20 is charged to multiple potentials in the same manner as described above.

According to this modification, the film member 20 is configured with a three-layer structure, and specifically, a predetermined potential difference can be provided between the first surface 20a and the second surface 20b. Generally, it is assumed that the membrane member 20 is stored in a folded state until it is deployed in outer space. When the film member 20 is stored, the more layers the film member 20 has, the more electrical connections and wires are required. Therefore, it is effective to simplify the structure and facilitate handling by configuring the film member 20 in three layers.

FIG. 16 is a schematic configuration diagram when the reduction gear 1 is installed in front of the traveling direction A1 of the space debris 2. As shown in FIG.

In the example of FIG. 16, the tether 41c (see FIG. 1) in the above embodiment is replaced with a support member 41d. The support member 41d is a columnar member having a predetermined length, and rigidly connects the space debris 2 and the reduction gear transmission 1 to each other. Therefore, the distance between the space debris 2 and the membrane member 20 does not decrease when the membrane member 20 receives drag from the ion flow.

The structure and effects of the reduction gear 1 are the same as those of the above embodiment. Therefore, the deceleration device 1 can adjust the deceleration rate of the space debris 2 by controlling the attitude of the membrane member 20 on the same principle either in front of or behind the space debris 2 .

(Second embodiment)
The reduction gear transmission 1 of the second embodiment shown in FIG. 17 is compatible with PMD. In this embodiment, the description of the same parts as those of the configuration shown in the first embodiment may be omitted.

Unlike the first embodiment, the speed reduction gear 1 of this embodiment does not have the satellite main body 10 (see FIG. 1) or the capture mechanism 41 (see FIG. 1). In this embodiment, the mounting device 40 includes fixtures 42 that directly fix the space debris 2 to the membrane member 20 . Alternatively, the attachment device 40 may include a tether 41c as shown in FIG. 1, and may mechanically connect the space debris 2 and the membrane member 20 via the tether 41c.

The reduction gear 1 of the present embodiment targets satellites and debris of rockets as the space debris 2 . The reduction gear 1 is preliminarily mounted on a satellite or a rocket before launching the satellite or the rocket, and is deployed upon completion of their operation.

The action and effect of the deceleration device 1 are the same as those of the first embodiment, and by electrifying at least part of the plurality of regions R, the attitude of the film member 20 can be controlled and the deceleration rate of the space debris 2 can be adjusted.

According to this embodiment, there is no need to capture the space debris 2 in outer space, and reliable adjustment of the deceleration rate of the space debris 2 can be expected.

FIG. 18 is a side view of space debris 2 showing a modification of the speed reduction gear 1 according to the second embodiment.

In this modified example, part of the space debris 2 is the membrane member 20 . In the illustrated example, the wreckage of a rocket is shown as the space debris 2 , and the side surface of the space debris 2 is the film member 20 .

The action and effect of the speed reduction device 1 of this modified example are the same as those described above, and the attitude of the film member 20 can be controlled by electrifying a portion of the plurality of regions R, and the speed reduction rate of the space debris 2 can be adjusted.

FIG. 19 is a schematic diagram showing the sheath when the membrane member 20 is charged to a positive potential.

In order to control the attitude of the film member 20, the control device 11 may control the charging device 30 so as to charge each of the plurality of regions R to a positive potential. As a result, a region Sp based on a positive potential (in this case, an electronic sheath) is formed for each of the plurality of regions R of the membrane member 20, and the ion flow A2 repels the region Sp to obtain a drag force. be done. Therefore, as shown in FIGS. 5 to 10, the posture of the film member 20 can be controlled by electrifying a portion of the plurality of regions R. FIG.

Therefore, each of the plurality of regions R of the first surface 20a of the film member 20 can obtain drag from ions not only by being charged to a negative potential, but also by being charged to a positive potential.

As described above, specific embodiments and modifications thereof of the present invention have been described, but the present invention is not limited to the above embodiments, and various changes can be made within the scope of the present invention. For example, an embodiment of the present invention may be an appropriate combination of contents of individual embodiments or modifications.

Also, for example, referring to FIGS. 20 and 21 , the membrane member 20 may have a relatively large base portion 25 and a relatively small laminated portion 26 laminated on the base portion 25 . The base 25 has two conductors 25a, 25b and a nonconductor (insulator) 25c disposed between the two conductors 25a, 25b. The two conductors 25 a and 25 b and the non-conductor 25 c are squares of the same size when viewed from the front of the membrane member 20 . The laminated portion 26 has a conductor 26a and a nonconductor (insulator) 26b. The conductor 26a and the non-conductor 26b are rectangles of the same size when viewed from the front of the membrane member 20. As shown in FIG. The long side of the conductor 26a is approximately the same length as one side of the conductor 25a, and the conductor 26a is arranged along one side of the conductor 25a. Conductor 26a is attached to conductor 25a via non-conductor 26b. Different voltages can be applied to conductor 25a, conductor 25b, and conductor 26a via power supply 31. FIG. In particular, the voltage applied to the conductor 26a is variable. The conductors 25a and 26a constitute a first surface 20a including a plurality of regions R, and the conductor 25b constitutes a second surface 20b. For example, the first surface 20a is set to a negative potential and the second surface 20b is set to a positive potential. As in this modified example, the plurality of regions R may not be provided on the same plane, and may be provided on two or more stacked planes.

Also, for example, a part of the second surface 20b may be made of a conductor, and the area of the conductor portion may be smaller than the total area of the first surface 20a and the second surface 20b. This makes it easier to maintain the potentials of the first surface 20a and the second surface 20b at desired values. In addition, the second surface 20b may be divided into a plurality of regions and applied with a potential as in the case of the first surface 20a.

Further, although adjustment of the deceleration rate of the space debris 2 has been exemplified as an application of the reduction gear 1, various other applications of the reduction gear 1 are conceivable. For example, the deceleration device 1 may be used to adjust the deceleration rate of an artificial satellite, planetary probe, or the like as an object.

1 reduction gear 2 space debris (object)
10 satellite body (grounding part)
Reference Signs List 11 control device 12 attitude detection device 20 film member 20a first surface 20b second surface 21 frame 22 support member 23 multiple film pieces 23a first conductor 23b second conductor 23c third conductor 23d first nonconductor 23e second second Nonconductor 23f First conductor 23g Second conductor 23h Nonconductor 24 Insulating sheet 25 Base 25a, 25b Conductor 25c Nonconductor 26 Laminate 26a Conductor 26b Nonconductor 30 Charging device 31 Power source 32 Main hot line 33 Sub hot line 40 Mounting device 41 Capturing Mechanism 41a Grasping Part 41b Injection Device 41c Tether 41d Supporting Member 42 Fixing Tool 200 Membrane Member 200a First Surface 200b Second Surface R Multiple Areas

Claims (7)

A deceleration device capable of adjusting the deceleration rate of an object moving in outer space,
a membrane member attached to or forming part of the object and having a first surface including a plurality of electrically isolated regions;
a charging device electrically connected to the film member and charging each of the plurality of regions;
and a control device that controls the voltage applied to each of the plurality of regions by the charging device. 2. The reduction gear transmission according to claim 1, wherein said film member has a plurality of film pieces forming each of said plurality of regions. further comprising an orientation detection device that detects the orientation of the membrane member;
3. The reduction gear transmission according to claim 1, wherein said control device controls said charging device according to the attitude of said film member detected by said attitude detection device. The membrane member has the first surface and a second surface opposite to the first surface,
The charging device is capable of charging the first surface and the second surface to different potentials,
4. The charging device according to any one of claims 1 to 3, wherein said control device controls said charging device so as to charge said first surface to a negative potential lower than said second surface by a predetermined potential difference. Reducer as described. The membrane member is
a first conductor made of a conductive material forming the first surface;
a second conductor made of a conductive material forming the second surface;
a third conductor made of a conductive material disposed between the first conductor and the second conductor;
a first non-conductor made of an insulating material or a dielectric material disposed between the first conductor and the third conductor;
5. The reduction gear transmission according to claim 4, further comprising: a second non-conductor made of an insulating material or a dielectric material and arranged between the second conductor and the third conductor. The membrane member is
a first conductor made of a conductive material forming the first surface;
a second conductor made of a conductive material forming the second surface;
5. The reduction gear transmission according to claim 4, further comprising: a non-conductor made of an insulator material or a dielectric material arranged between the first conductor and the second conductor. 4. The reduction gear transmission according to any one of claims 1 to 3, wherein said control device controls said charging device so as to charge each of said plurality of regions to a positive potential.

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