JP5417643B2 - Superconducting magnet device for space and propulsion device for space - Google Patents

Description

  The present invention relates to a space superconducting magnet device and a space propulsion device mounted on a spacecraft.

  As a propulsion device for spacecraft such as artificial satellites, development of a magnetic plasma sail (MPS) has been underway.

  The magnetoplasma sail injects a plasma jet into a strong magnetic field to carry the magnetic field far and expand the magnetosphere, and obtains a propulsive force through the interaction between the magnetosphere and solar wind plasma (see Non-Patent Document 1, for example). Magnetic plasma sails are expected to be applied to exoplanets and deep space exploration vehicles because they have greater thrust than ion engines and can fly spacecraft at high speed.

  It is conceivable to use a superconducting coil in order to obtain a strong magnetic field necessary for the magnetic plasma sail. In order to obtain a magnetic field with the superconducting coil, it is necessary to cool the superconducting coil below the superconducting transition temperature. For cooling the superconducting coil, liquid helium or a small refrigerator is generally used. An example of using a superconducting coil in outer space is the ASTROMAG project (for example, see Non-Patent Document 2), and there is an example in which the superconducting coil is cooled by liquid helium. On the other hand, a Stirling refrigerator using a Stirling cycle has been developed as a small-sized refrigerator for space use (for example, see Non-Patent Document 3).

  A method of cooling a superconducting coil using radiation cooling to outer space is known (see, for example, Patent Document 1).

  Furthermore, a radiation cooler is known as a cooling method for obtaining a low temperature in outer space (see, for example, Non-Patent Document 4).

JP 2008-91923 A

Kazuyuki Funaki and Hiroshi Yamakawa, “Research of Magnetic Plasma Sail and Challenge to Deep Space Exploration”, Journal of Plasma and Fusion Research, Society of Plasma and Fusion, 2007, Vol. 83, No. 3, p. 281-284 Supervised by Toyoichiro Nobuki and Akira Hirai, edited by Toichi Okada, “Cryogenic Engineering Handbook”, Uchida Otsuru Farm Shinsha, 1982, p. 930 Supervised by Toyoichiro Nobuki and Akira Hirai, edited by Toichi Okada, “Cryogenic Engineering Handbook”, Uchida Otsuru Farm Shinsha, 1982, p. 932-934 Supervised by Toyoichiro Nobuki and Akira Hirai, edited by Toichi Okada, “Cryogenic Engineering Handbook”, Uchida Otsuru Farm Shinsha, 1982, p. 931-932

  When liquid helium is used for cooling the superconducting coil, it becomes difficult to keep the superconducting coil at a temperature equal to or lower than the superconducting transition temperature if the liquid helium is consumed and depleted due to temperature rise and vaporization accompanying heat exchange.

  On the other hand, space-type refrigerators have a problem in terms of reliability in long-term operation (generally 10 years or more) required in deep space exploration. In deep space exploration, the output from the solar cell decreases as the distance from the sun increases, making it difficult to secure the power necessary to continuously operate a small space refrigerator. Furthermore, after the spacecraft heads for deep space exploration, it will be impossible to maintain a small space refrigerator.

  On the other hand, in the case of a conventional radiant cooler that obtains a low temperature by using radiant cooling, it is possible to ensure a long-term life, and a large amount of power (about 40 W, non-operating) for operation like a refrigerator. (See Patent Document 3). The low temperature obtained in this case is about 70 K to 100 K (see Non-Patent Document 4), and for example, a high temperature superconducting coil that transitions above the liquid nitrogen temperature can be operated. However, since the current density is low when the high temperature superconducting coil is used above the temperature of liquid nitrogen, in order to generate the magnetic field required for the magnetic plasma sail, the high temperature superconducting coil is made larger or lower than the superconducting transition temperature. Need to cool down. Transportation means such as a rocket that transports a spacecraft from the ground to outer space have a limited transportable mass (launch capability). For this reason, if the high temperature superconducting coil becomes large and the mass becomes heavy, it becomes difficult to apply the superconducting coil to the spacecraft. In order to obtain a strong magnetic field while reducing the weight of the high-temperature superconducting coil, it is necessary to obtain a low temperature of about 20K.

  Therefore, the present invention proposes a space superconducting magnet device and a space propulsion device that can cool a superconducting coil to a sufficient temperature range below the superconducting transition temperature and can easily ensure a long life. .

In order to solve the above problems, a superconducting magnet device for space according to the present invention includes a superconducting coil, an exciting device for exciting the superconducting coil, a current lead for electrically connecting the superconducting coil and the exciting device, A plurality of stages having a radiation cooling surface while being thermally connected to at least one of a support structure for supporting the superconducting coil on a spacecraft bus, and the superconducting coil, the current lead, and the support structure A heat shield plate and a sun shield provided in the bus portion , wherein the heat shield plate is formed in a cylindrical shape or a polygonal cylindrical shape having a bottom surface, and the axis is the axis of the superconducting coil. It is arranged on a substantially extended line .

The space propulsion device according to the present invention includes a superconducting coil, an exciting device for exciting the superconducting coil, a current lead for electrically connecting the superconducting coil and the exciting device, and the superconducting coil as a spacecraft. A plurality of heat shield plates that are thermally connected to at least one of the superconducting coil, the current lead, and the support structure and have a radiation cooling surface; The heat shield plate is formed in a cylindrical shape or a polygonal cylindrical shape having a bottom surface, and an axis of the heat shield plate is disposed on a substantially extended line of the axis of the superconducting coil. A space superconducting magnet device, and a plasma generator for expanding the magnetosphere of the magnetic field generated by the space superconducting magnet device.

  According to the present invention, it is possible to propose a space superconducting magnet device and a space propulsion device that can cool a superconducting coil to a sufficient temperature range below the superconducting transition temperature and can easily ensure a long life. .

BRIEF DESCRIPTION OF THE DRAWINGS The schematic block diagram which showed the spacecraft provided with the space superconducting magnet apparatus and space propulsion apparatus which concern on 1st Embodiment of this invention. 1 is a partial sectional view showing a space superconducting magnet apparatus according to a first embodiment of the present invention. 1 is a perspective view showing a heat shield plate of a space superconducting magnet apparatus according to a first embodiment of the present invention. 1 is a perspective view showing a heat shield plate of a space superconducting magnet apparatus according to a first embodiment of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS The schematic block diagram which showed the spacecraft provided with the space superconducting magnet apparatus and space propulsion apparatus which concern on 1st Embodiment of this invention. The figure which illustrated the relationship between the temperature in the radiation cooling surface of the space superconducting magnet apparatus which concerns on 1st Embodiment of this invention, and the amount of radiation cooling per unit area. The figure which illustrated the relationship between the number of steps of the radiation cooling surface (heat shield board) of the space superconducting magnet device concerning a 1st embodiment of the present invention, and the amount of heat penetration. The figure which illustrated the relationship between the step number of the radiation cooling surface (heat shield board) of the space superconducting magnet apparatus which concerns on 1st Embodiment of this invention, and its total area. The figure which illustrated the relationship between the number of steps and the mass of the radiation cooling surface (heat shield plate) of the space superconducting magnet apparatus according to the first embodiment of the present invention. The schematic block diagram which showed the space superconducting magnet apparatus and space propulsion apparatus which concern on 2nd Embodiment of this invention. The schematic block diagram which showed the space superconducting magnet apparatus and space propulsion apparatus which concern on 3rd Embodiment of this invention. The schematic block diagram which showed the space superconducting magnet apparatus and space propulsion apparatus which concern on 4th Embodiment of this invention. The schematic block diagram which showed the space superconducting magnet apparatus and space propulsion apparatus which concern on 5th Embodiment of this invention. The schematic block diagram which showed the space superconducting magnet apparatus and space propulsion apparatus which concern on 6th Embodiment of this invention. The schematic block diagram which showed the space superconducting magnet apparatus and space propulsion apparatus which concern on 6th Embodiment of this invention.

  DESCRIPTION OF EMBODIMENTS Embodiments of a space superconducting magnet device and a space propulsion device according to the present invention will be described with reference to FIGS.

[First Embodiment]
A space superconducting magnet device and a space propulsion device according to a first embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 is a schematic configuration diagram showing a spacecraft including a space superconducting magnet device and a space propulsion device according to a first embodiment of the present invention. FIG. 1 is a diagram schematically showing the flight state of the spacecraft 1.

  As shown in FIG. 1, the spacecraft 1 is a spacecraft used for deep space exploration, for example. The spacecraft 1 includes a bus module 3 (bus unit) and a space propulsion device 4 provided in the bus module 3. The space propulsion device 4 is a magnetic plasma sail including a space superconducting magnet device 5 and a plasma jet injection device 6 (plasma generator).

  The bus module 3 includes a main structure (not shown), an attitude control system (not shown), a power supply system 9 having a solar cell 8, a telemetry command ranging system (not shown), and a propulsion system (not shown). A machine bus system (not shown) and a mounting system (not shown) having an observation device (not shown) provided in the main structure. The space propulsion device 4 constitutes a part of the propulsion system of the bus module 3.

  The space superconducting magnet device 5 includes a superconducting coil support structure 11 (support structure) provided in the bus module 3, a superconducting coil 12 supported by the superconducting coil support structure 11, and a superconductivity provided in the bus module 3. At least one of an exciting device 13 that excites the coil 12, a current lead 14 that electrically connects the superconducting coil 12 and the exciting device 13, and a superconducting coil support structure 11, the superconducting coil 12, and the current lead 14. A plurality of heat shield plates 17 that are thermally connected and have a radiation cooling surface 16 and a sun shield 19 provided in the bus module 3 are provided.

  The superconducting coil support structure 11 is a truss-like or ramen-like structure that supports the superconducting coil 12 on the main structure of the bus module 3. The superconducting coil support structure 11 has sufficient strength and rigidity to support the superconducting coil 12 in the launch environment of the spacecraft 1 transported to the space S by a transportation means such as a rocket.

  Superconducting coil 12 has a tape-shaped metal substrate (not shown), an intermediate layer (not shown) formed on the metal substrate, and an oxide superconducting layer (not shown) formed on the intermediate layer. This is a high-temperature superconducting coil formed by winding a tape-shaped yttrium-based high-temperature superconducting wire in a coil shape. Superconducting coil 12 has a high superconducting transition temperature (above liquid nitrogen temperature). Further, the superconducting coil 12 has excellent mechanical strength and has a high allowable stress, and can be easily reduced in weight when mounted on the spacecraft 1. The axis of superconducting coil 12 (the chain line c in FIG. 1) is arranged along the longitudinal axis direction of spacecraft 1.

  The respective heat shield plates 17 are arranged in alignment toward the longitudinal axis of the spacecraft 1. Here, the heat shield plate 17 approaches the bus module 3 in the order of the first stage, the second stage,... From the one arranged far from the bus module 3.

  The heat shield plate 17 is painted black with the surface facing the outer space S in the flight state of the spacecraft 1 as the radiation cooling surface 16. The heat shield plate 17 is thermally connected to the superconducting coil 12 (heat shield plate 21), and is thermally connected to at least one of the superconducting coil support structure 11 and the current lead 14 (heat There is a shield plate 22). Each heat shield plate 17 is supported by a heat shield plate support member (not shown) provided in the superconducting coil 12.

  Further, the heat shield plate 17 includes an axial core (indicated by a one-dot chain line c in FIG. 1) disposed on a substantially extended line of the axial core of the cylindrical superconducting coil 12 (indicated by a one-dot chain line c in FIG. 1) and at least one bottom surface. Are formed into a hollow cylindrical shape or a hollow polygonal cylindrical shape.

  The sun shield 19 shields the superconducting coil support structure 11, the superconducting coil 12, the current lead 14 and the heat shield plate 17 from the radiant heat H of the sun Sun in the flight posture of the spacecraft 1.

  Here, each step of the heat shield plate 17 is formed such that the outer diameter dimension is smaller as it is located farther from the sun shield 19, and in particular, the circumferential length of the cylindrical side surface portion is smaller. As a result, even when the attitude of the spacecraft 1 with respect to the sun Sun is inclined due to an attitude control error or the like, the sunshield 19 is positioned away from the sunshield 19 by placing the heat shield plate 17 in the shaded portion. The heat shield plate 17 can be reliably shielded from the radiant heat H of the sun.

  FIG. 2 is a partial cross-sectional view showing the space superconducting magnet apparatus according to the first embodiment of the present invention.

  As shown in FIG. 2, the superconducting coil 12 of the space superconducting magnet device 5 is held by the bus module 3 by a superconducting coil support structure 11 that is a truss-like or ramen-like structure.

  The heat shield plate 21 thermally connected to the superconducting coil 12 is formed so as to surround the superconducting coil 12. The heat shield plate 21 is provided with a black coating as the radiation cooling surface 16 on the outer surface 21a and the outer bottom surface 21b facing the outer space, and the outer surface facing the other inner surface 21c, inner bottom surfaces 21d and 21e, and the bus module 3. The bottom surface 21f is made of a mirror surface or a multilayer heat insulating material (Multi Layer Insulation, MLI). The heat shield plate 21 efficiently radiates heat from the superconducting coil 12 toward outer space, and heat that enters the superconducting coil 12 from the inner bottom surface 22c of the second stage heat shield plate 22 by radiation (radiation). Reduce.

  The heat shield plate 21 is made of an aluminum alloy. Thereby, the heat shield plate 21 prevents the cosmic rays from directly hitting the superconducting coil 12.

  The heat shield plate 22 thermally connected to at least one of the superconducting coil support structure 11 and the current lead 14 is formed in a bottomed cylindrical shape with one bottom surface opened. The bottom surface 23 of the heat shield plate 22 has a support structure through hole 23a through which the superconducting coil support structure 11 is inserted and a current lead through hole 23b through which the current lead 14 is inserted.

  Between the superconducting coil support structure 11 and the heat shield plate 22, the support provided between the beam member 25 or the node member 26 of the superconducting coil support structure 11 and the bottom surface 23 around the support structure through-hole 23a. Thermally connected via the material heat anchor 28.

  The current lead 14 and the heat shield plate 22 are thermally connected via a current lead thermal anchor 29 provided between a middle portion of the current lead 14 and a bottom surface portion 23 around the current lead through hole 23b. Is done. As a result, the heat shield plate 22 reduces the heat entering the superconducting coil 12 by conduction from the superconducting coil support structure 11 or the current lead 14.

  The heat shield plate 22 is provided with a black coating as the radiation cooling surface 16 on the outer surface 22a facing the outer space, and the other inner surface 22b, the inner bottom surface 22c and the outer bottom surface 22d facing the bus module 3 are mirror surfaces or multilayer heat insulating materials. (MLI). As a result, the heat shield plate 22 reduces the heat entering the superconducting coil 12 by radiation (radiation) from the heat shield plate 22 on the high temperature side (heat shield plate 22 located on the side close to the bus module 3).

  3 and 4 are perspective views showing a heat shield plate of the space superconducting magnet apparatus according to the first embodiment of the present invention.

  As shown in FIG. 3, the axial core of the superconducting coil 12 of the space superconducting magnet device 5 (the chain line c in FIG. 3) is arranged along the longitudinal axis direction of the spacecraft 1.

  On the other hand, as shown in FIG. 4, the axis of the superconducting coil 12 of the space superconducting magnet device 5 (the chain line c in FIG. 4) can be disposed along the longitudinal axis crossing direction of the spacecraft 1. .

  In the spacecraft 1, it can be considered that the superconducting coil 12 that generates a magnetic field necessary for the magnetic plasma sail is arranged in the flight posture as shown in FIG. 3 or FIG. In addition, as shown in FIG. 3, it is more advantageous in terms of resistance to the mounting capacity and launch environment for the transportation means when the axis of the superconducting coil 12 is arranged along the longitudinal axis direction of the spacecraft 1.

  FIG. 5 is a schematic configuration diagram showing a spacecraft including the space superconducting magnet device and the space propulsion device according to the first embodiment of the present invention.

  As shown in FIG. 5, the space propulsion device 4 of the spacecraft 1 generates plasma from the plasma jet injection device 6 against the magnetic field S1 (solid line S1 in FIG. 5) formed by the superconducting coil 12 of the space superconducting magnet device 5. By injecting (broken line P in FIG. 5), the expanded magnetosphere S2 (solid line S2 in FIG. 5) is developed around the spacecraft 1. The spacecraft 1 receives solar wind plasma in the magnetosphere S2 and obtains a propulsive force through these interactions.

  The temperature of the superconducting coil 12 of the space superconducting magnet device 5 configured as described above is determined by the balance between the amount of radiation cooling and the amount of heat penetration.

  First, the amount of radiation cooling is radiation of heat from the space superconducting magnet device 5 to the space, and is determined from the temperature and radiation rate of the radiation cooling surface 16 of the heat shield plate 17.

  FIG. 6 is a diagram illustrating the relationship between the temperature on the radiation cooling surface of the space superconducting magnet apparatus according to the first embodiment of the present invention and the amount of radiation cooling per unit area.

As shown in FIG. 6, the amount of radiation cooling per unit area on the radiation cooling surface 16 has a fourth power relationship with the temperature of the radiation cooling surface 16 as the bottom. When the emissivity ε of the radiant cooling surface 16 coated with black is about 0.82, if the target cooling temperature of the superconducting coil 12 is 20K, the radiant cooling amount per unit area on the radiant cooling surface 16 is 7.4 mW. / M ² .

Here, the area of the radiation cooling surface 16 is limited to the mounting volume of a rocket which is a transport means for transporting the spacecraft 1 to outer space. For example, in the case of an H-IIA rocket equipped with a 4S type fairing, the spacecraft 1 having a diameter of 4 m and a height of about 10 m can be mounted. From this, the area of the radiation cooling surface 16 is about 100 m ^{2 at} the maximum. However, in consideration of the arrangement of other devices mounted on the spacecraft 1, the entire spacecraft 1 cannot be the radiation cooling surface 16, and the external dimensions of the bus module 3 of the spacecraft 1 are taken into consideration. The area of the radiant cooling surface 16 is desirably 30 m ² or less. In this case, the radiation cooling amount of the radiation cooling surface 16 is about 0.2 W (30 m ² × 7.4 mW / m ² ).

  The heat shield plate 21 thermally connected to the superconducting coil 12 has a radiation cooling surface 16 on the outer surface 21a and the outer bottom surface 21b so as to surround the superconducting coil 12. As shown in FIG. 6, as the temperature of the radiation cooling surface 16 is lower, the amount of radiation cooling per unit area of the radiation cooling surface 16 is smaller. Therefore, the total area of the radiation cooling surface 16 is expanded and the amount of radiation cooling is increased. It is to do.

  On the other hand, the amount of heat penetration includes radiant heat from the high temperature part and conduction heat from the superconducting coil support structure part 11 and the current lead 14. The amount of heat penetration due to radiation depends on the size (outer dimensions) of the superconducting coil 12. The amount of heat penetration from the superconducting coil support structure 11 due to conduction depends on the mass of the superconducting coil 12, and the amount of heat penetration from the current lead 14 due to conduction depends on the energization current of the superconducting coil 12.

  Therefore, the evaluation of the heat penetration amount requires the design of the superconducting coil 12.

Here, the superconducting coil 12 and the heat shield plate 17 having a magnetomotive force of 10 ⁶ A and mounted on the H-IIA rocket and launched can be designed.

  Specifically, the amount of heat penetration to the target cooling temperature (20 K) of the superconducting coil 12 was calculated with the temperature of the bus module 3 as the high temperature part as 300 K as design conditions and the number of stages of the heat shield plate 17 as a parameter.

  FIG. 7 is a diagram illustrating the relationship between the number of steps of the radiation cooling surface (heat shield plate) of the space superconducting magnet device according to the first embodiment of the present invention and the amount of heat penetration.

  FIG. 8 is a diagram illustrating the relationship between the number of steps of the radiation cooling surface (heat shield plate) and the total area of the superconducting magnet device for space according to the first embodiment of the present invention.

  As shown in FIG. 7, the amount of heat penetration into the target cooling temperature (20K) of the superconducting coil 12 decreases as the number of stages of the heat shield plate 17 increases. At this time, as shown in FIG. 8, the total area of the radiation cooling surface 16 decreases as the number of steps of the heat shield plate 17 increases. If the heat shield plate 17 has three or more stages, the heat penetration amount is smaller than 0.2W. Note that the effect of reducing the heat penetration amount is significant when the number of steps of the heat shield plate 17 is about four. The effect of reducing the total area of the radiation cooling surface 16 is also the same.

  Accordingly, since the radiation cooling amount of the radiation cooling surface 16 at the target cooling temperature (20 K) of the superconducting coil 12 is 0.2 W or less, considering the balance between the radiation cooling amount and the heat penetration amount, the space superconducting magnet device 5 is used. In addition, the space propulsion device 4 requires the three-stage heat shield plate 17 to cool the superconducting coil 12 to 20K or less, and more preferably includes four or more stages of the heat shield plate 17.

  Here, the reduction of the amount of heat penetration reduces the area of the radiation cooling surface 16, and the mass of the heat shield plate 17 can be reduced. On the other hand, an increase in the number of steps of the heat shield plate 17 increases the mass of the heat shield plate 17.

  Therefore, the relationship between the number of steps of the heat shield plate 17 and the mass was examined.

  FIG. 9 is a diagram illustrating the relationship between the number of stages and the mass of the radiation cooling surface (heat shield plate) of the space superconducting magnet apparatus according to the first embodiment of the present invention.

  As shown in FIG. 9, the heat shield plate 17 can be reduced in mass by being configured from four to six stages.

  The space superconducting magnet device 5 and the space propulsion device 4 according to this embodiment cool the superconducting coil 12 that generates a magnetic field necessary for the magnetic plasma sail by radiative cooling of the heat shield plate 17. Thereby, the superconducting magnet device 5 for space and the propulsion device 4 for space do not require maintenance like a cooling device having a driving member such as a refrigerator.

[Second Embodiment]
A second embodiment of the space superconducting magnet device and space propulsion device according to the present invention will be described with reference to FIG.

  FIG. 10 is a schematic configuration diagram showing a space superconducting magnet device and a space propulsion device according to the second embodiment of the present invention.

  In the space superconducting magnet device 5A and the space propulsion device 4A according to the present embodiment, the same components as those of the space superconducting magnet device 5 and the space propulsion device 4 of the first embodiment are denoted by the same reference numerals, and redundant description is given. Is omitted.

  As shown in FIG. 10, the space superconducting magnet device 5 </ b> A and the space propulsion device 4 </ b> A of the spacecraft 1 </ b> A include a permanent current switch 31 connected to the current lead 14.

  The permanent current switch 31 is arranged in parallel with the superconducting coil 12 and connected to the current lead 14. The permanent current switch 31 is composed of a coil that is wound non-inductively, and is turned off in a normal conducting state (high resistance state), and is turned on in a superconducting state (resistance is approximately 0Ω). When supplying power from the exciter 13 to the superconducting coil 12 to increase the coil current, the permanent current switch 31 is turned off, and when the coil current of the superconducting coil 12 reaches a required current value, the permanent current switch 31 is turned on. To. Thereby, the space superconducting magnet device 5A maintains the magnetic field of the superconducting coil 12 even if the superconducting coil 12 is once excited and then the power supply from the exciting device 13 is cut off, thereby reducing the power consumption for generating the magnetic field. it can.

  Note that the coil current of the superconducting coil 12 after being excited gradually attenuates. For this reason, the space superconducting magnet device 5A and the space propulsion device 4A are required to excite the superconducting coil 12, although it is necessary to periodically turn off the permanent current switch 31 and restart the supply of power from the exciting device 13. Average power consumption can be greatly reduced.

[Third Embodiment]
A third embodiment of the space superconducting magnet device and space propulsion device according to the present invention will be described with reference to FIG.

  FIG. 11 is a schematic configuration diagram showing a space superconducting magnet device and a space propulsion device according to a third embodiment of the present invention.

  In the space superconducting magnet device 5B and the space propulsion device 4B according to the present embodiment, the same components as those of the space superconducting magnet device 5 and the space propulsion device 4 according to the first embodiment are denoted by the same reference numerals, and redundant description is given. Is omitted.

  As shown in FIG. 11, the space superconducting magnet device 5 </ b> B and the space propulsion device 4 </ b> B of the spacecraft 1 </ b> B include an excitation device 13 </ b> B connected to the current lead 14.

  Excitation device 13B is arranged outside the sun shield 19 in the axis crossing direction as seen in the axis direction of spacecraft 1B. That is, the excitation device 13B does not enter the shadow of the sunshield 19 in the flying posture of the spacecraft 1B.

  In addition, the exciting device 13B heats the thermoelectric element 33 electrically connected to the current lead 14, the heat receiving plate 34 thermally connected to the high temperature side electrode of the thermoelectric element 33, and the low temperature side electrode of the thermoelectric element 33. Connected to the heat sink 35.

  The heat receiving plate 34 has a heat receiving surface 34a that is exposed to solar radiation heat in the flight posture of the spacecraft 1B.

  The heat radiating plate 35 has a radiation cooling surface 35a that is arranged in the shadow of the heat receiving plate 34 in the flight posture of the spacecraft 1B and radiates heat to outer space.

  The thermoelectric element 33 generates a thermoelectromotive force due to a temperature difference between the high temperature side electrode and the low temperature side electrode, and generates a current in the superconducting coil 12 via the current lead 14.

  Therefore, the space superconducting magnet device 5B and the space propulsion device 4B can excite the superconducting coil 12 by the thermoelectromotive force generated by the thermoelectric element 33, and the electric power supplied from the bus module 3 of the spacecraft 1B. The power consumption of the spacecraft 1B as a whole can be reduced.

[Fourth Embodiment]
A fourth embodiment of the space superconducting magnet device and space propulsion device according to the present invention will be described with reference to FIG.

  FIG. 12 is a schematic configuration diagram showing a space superconducting magnet device and a space propulsion device according to a fourth embodiment of the present invention.

  In the space superconducting magnet device 5C and the space propulsion device 4C according to the present embodiment, the same components as those in the space superconducting magnet device 5 and the space propulsion device 4 of the first embodiment are denoted by the same reference numerals, and redundant description is given. Is omitted.

  As shown in FIG. 12, the space superconducting magnet device 5C and the space propulsion device 4C of the spacecraft 1C include a magnetic shield superconducting coil 37 supported by the superconducting coil support structure 11 and a magnetic shield superconducting coil 37. The repulsive force support structure part 38 provided, and the superconducting coil 12 supported by the repulsive force support structure part 38 are provided.

  The magnetic shield superconducting coil 37 is housed in the heat shield plate 21 together with the superconducting coil 12 and is cooled to the superconducting transition temperature or lower by the heat shield plate 17. Thereby, the space superconducting magnet device 5C and the space propulsion device 4C magnetically shield and protect the bus module 3 from the magnetic field generated by the superconducting coil 12 by the magnetic field generated by the magnetic shielding superconducting coil 37.

  The magnetic shield superconducting coil 37 is connected to the superconducting coil 12 in series. Thereby, the space superconducting magnet device 5C and the space propulsion device 4C can excite the superconducting coil 12 and the magnetic shield superconducting coil 37 by the common exciting device 13, and the exciting device for each superconducting coil. Compared with the case of providing a small, it is possible to reduce the size and weight.

  The repulsive support structure 38 is a truss-like or ramen-like structure similar to the superconducting coil support structure 11. The space superconducting magnet device 5C and the space propulsion device 4C house the superconducting coil 12 and the magnetic shield superconducting coil 37 in a common heat shield plate 21, and the repulsive force acting on each superconducting coil is generated by the repulsive support structure 38. Since it is held directly, a structure related to holding repulsive force can be easily configured.

[Fifth Embodiment]
A fifth embodiment of the space superconducting magnet device and space propulsion device according to the present invention will be described with reference to FIG.

  FIG. 13 is a schematic configuration diagram showing a space superconducting magnet device and a space propulsion device according to a fifth embodiment of the present invention.

  In the space superconducting magnet device 5D and the space propulsion device 4D according to the present embodiment, the same components as those in the space superconducting magnet device 5 and the space propulsion device 4 of the first embodiment are denoted by the same reference numerals, and redundant description is given. Is omitted.

  As shown in FIG. 13, the space superconducting magnet device 5 </ b> D and the space propulsion device 4 </ b> D of the spacecraft 1 </ b> D include an excitation device 13 </ b> D electrically connected to the power supply system 9.

  The power supply system 9 is electrically connected to the solar cell 8 supported by the main structure of the bus module 3 or the sun shield 19, the power supply control device 42 electrically connected to the solar cell 8, and the power supply control device 42. And a power supply bus line 43 for supplying power to each device mounted on the spacecraft 1D.

  The power control device 42 converts the output of the solar cell 8 into an appropriate common voltage and supplies power to each device mounted on the spacecraft 1D via the power bus line 43.

  The excitation device 13D includes a DC converter 45. The exciter 13D converts the electric power sent from the power supply bus line 43 into a voltage suitable for exciting the superconducting coil 12 by the DC converter 45 and supplies it. The DC converter 45 includes an input end electrically connected to the power supply bus line 43 of the bus module 3 and an output end electrically connected to the current lead 14.

  The space superconducting magnet device 5D and the space propulsion device 4D can share the power supply system of the spacecraft 1D among the devices by taking out the power for exciting the superconducting coil 12 from the power supply system 9 of the spacecraft 1D. This is possible, and the power utilization efficiency of the spacecraft 1D can be increased. The space superconducting magnet device 5D and the space propulsion device 4D include a DC converter 45 connected independently to the superconducting coil 12, and freely set the voltage and current supplied to the superconducting coil 12. The degree of freedom of operation of the superconducting coil 12 can be improved.

[Sixth Embodiment]
A sixth embodiment of the space superconducting magnet device and space propulsion device according to the present invention will be described with reference to FIGS.

  14 and 15 are schematic configuration diagrams showing a space superconducting magnet device and a space propulsion device according to a sixth embodiment of the present invention.

  In the space superconducting magnet device 5E and the space propulsion device 4E according to the present embodiment, the same components as those in the space superconducting magnet device 5 and the space propulsion device 4 according to the first embodiment are denoted by the same reference numerals, and redundant description is given. Is omitted.

  As shown in FIG. 14, the space superconducting magnet device 5E and the space propulsion device 4E of the spacecraft 1E include an excitation device 13E.

  The exciting device 13E includes a superconducting coil exciting solar cell 47 (second solar cell) electrically connected to the current lead 14. The superconducting coil excitation solar cell 47 is provided on the main structure of the bus module 3 or the sunshield 19. Further, the superconducting coil exciting solar battery 47 includes a plurality of solar cells (not shown) connected in parallel or a plurality of solar cells connected in parallel with a series of solar cell rows connected in series. .

  In general, the solar cell 8 of the bus module 3 includes a solar cell module (not shown) in which a large number of solar cells are connected in series, and a required output (by connecting a large number of solar cell modules in series and in parallel). Dozens of volts and several A) are obtained. On the other hand, the voltage and current necessary for exciting the superconducting coil 12 are several volts, several tens of A to several hundreds A. Therefore, in order to supply electric power necessary for exciting the superconducting coil 12 from the power supply system of the bus module 3, the DC converter 45 as in the fifth embodiment is required.

  Therefore, in the present embodiment, electric power necessary for exciting the superconducting coil 12 is obtained by the superconducting coil exciting solar battery 47 in which an appropriate number of solar cells are connected in series or in parallel to the exciting device 13E. The space superconducting magnet device 5E and the space propulsion device 4E connect the superconducting coil 12 directly to the superconducting coil exciting solar cell 47, thereby eliminating the need for the DC converter 45 and further reducing the size and weight of the spacecraft 1E. And loss of the power supply circuit can be reduced.

  As shown in FIG. 15, the excitation device 13E can also include an excitation control device 48 (power supply circuit). The excitation control device 48 includes an input terminal electrically connected to the superconducting coil exciting solar cell 47 and an output terminal electrically connected to the superconducting coil 12. The excitation control device 48 is configured using a switching element made of a semiconductor.

  The space superconducting magnet devices 5, 5A, 5B, 5C, 5D, and 5E and the space propulsion devices 4, 4A, 4B, 4C, 4D, and 4E according to the present embodiment radiate heat from the heat shield plates 17 in a plurality of stages. By doing so, the superconducting coil 12 can be cooled to a temperature considerably lower than the superconducting transition temperature. Specifically, the superconducting coil 12 can be cooled to about 20K. At this time, the mass and volume of the space superconducting magnet devices 5, 5A, 5B, 5C, 5D, and 5E and the space propulsion devices 4, 4A, 4B, 4C, 4D, and 4E are based on existing transportation means such as rockets. It can be configured to be transportable from the ground to outer space.

  The space superconducting magnet devices 5, 5A, 5B, 5C, 5D, and 5E and the space propulsion devices 4, 4A, 4B, 4C, 4D, and 4E according to the present embodiment are superconducted by the heat shield plates 17 in a plurality of stages. By cooling the coil 12, a large amount of power for operation (about 40 W, see Non-Patent Document 3) is not consumed like a refrigerator.

  Furthermore, the space superconducting magnet devices 5, 5A, 5B, 5C, 5D, and 5E and the space propulsion devices 4, 4A, 4B, 4C, 4D, and 4E according to the present embodiment have a low temperature obtained by a conventional radiation cooler. It is possible to obtain a temperature much lower than (about 70K to 100K, see Non-Patent Document 4), and a strong magnetic field can be obtained while suppressing the mass of the superconducting coil 12.

  Therefore, according to the present invention, it is possible to cool the superconducting coil 12 to a sufficient temperature range (about 20 K) below the superconducting transition temperature (approximately liquid nitrogen temperature) and to easily ensure a long life. is there.

1, 1A, 1B, 1C, 1D, 1E Spacecraft 3 Bus module 4, 4A, 4B, 4C, 4D, 4E Space propulsion device 5, 5A, 5B, 5C, 5D, 5E Space superconducting magnet device 6 Plasma jet Injecting device 8 Solar cell 11 Superconducting coil support structure 12 Superconducting coils 13, 13B, 13D, 13E Excitation device 14 Current lead 16 Radiation cooling surface 17 Heat shield plate 19 Sun shield 21 Heat shield plate 21a Outer side surface 21b Outer bottom surface 21c Inner side surface 21d, 21e Inner bottom surface 21f Outer bottom surface 22 Heat shield plate 22a Outer side surface 22b Inner side surface 22c Inner bottom surface 22d Outer bottom surface 23 Bottom surface portion 23a Support structure through hole 23b Current lead through hole 25 Beam member 26 Node member 28 Support material thermal anchor 29 Current lead thermal anchor 31 Permanent current switch 33 Thermoelectric element 34 Heat receiving plate 34a Surface 35 radiating plate 35a radiative cooling surface 37 magnetically shielding the superconducting coil 38 repulsion support structure 41 supply system 42 power control unit 43 power supply bus lines 45 DC converter 47 superconducting coil excitation solar cell 48 excitation control device

Claims (17)

A superconducting coil;
An exciting device for exciting the superconducting coil;
A current lead for electrically connecting the superconducting coil and the excitation device;
A support structure for supporting the superconducting coil on a spacecraft bus,
A plurality of heat shield plates thermally connected to at least one of the superconducting coil, the current lead, and the support structure and having a radiation cooling surface;
A sunshield provided in the bus part ,
The space superconducting magnet device is characterized in that the heat shield plate is formed in a cylindrical shape or a polygonal cylindrical shape having a bottom surface, and an axis of the heat shield plate is disposed on a substantially extended line of the axis of the superconducting coil . The space superconducting magnet device according to claim 1, wherein the superconducting coil is a high temperature superconducting coil composed of a high temperature superconducting wire. 3. The space superconducting magnet device according to claim 2, wherein the high-temperature superconducting wire is a tape-shaped high-temperature superconducting wire in which an intermediate layer and an oxide superconducting layer are formed on a metal substrate. The space superconducting magnet device according to any one of claims 1 to 3, further comprising a permanent current switch connected in parallel to the superconducting coil. The space superconducting magnet device according to any one of claims 1 to 4, wherein the heat shield plate has any number of stages from four to six. The space superconducting magnet apparatus according to any one of claims 1 to 5, wherein the superconducting coil is surrounded by the heat shield plate thermally connected to the superconducting coil. Each stage, space for a superconducting magnet apparatus according to claim 1, characterized in that as the circumferential length away from the sunshield is reduced in the heat shield plate. Space for a superconducting magnet apparatus according to 7 claims 1, wherein the superconducting coil with superconducting coils for magnetic shielding which shields the bus portion magnetically from the magnetic field to be generated. The space superconducting magnet apparatus according to claim 8 , wherein the superconducting coil and the magnetic shielding superconducting coil are surrounded by the same heat shield plate. The space superconducting magnet apparatus according to claim 8 or 9 , wherein the magnetic shield superconducting coil is connected in series to the superconducting coil. The space superconducting magnet apparatus according to any one of claims 1 to 10 , wherein the excitation device includes a thermoelectric element electrically connected to the current lead. A heat receiving plate thermally connected to the high temperature side electrode of the thermoelectric element;
Space for a superconducting magnet apparatus according to claim 1 1 in which the heat sink is thermally connected to the low temperature side electrode, comprising the to the thermoelectric element. The spacecraft includes a power supply system that obtains electric power from a solar cell,
The excitation device is 0 to claim 1 1, further comprising a DC converter with and electrically connected to the output terminal to the current lead electrically connected to each input terminal to the power supply system The superconducting magnet device for space according to any one of the above. The DC converter, for space superconducting magnet apparatus according to claim 1 3, characterized by controlling the excitation current of the superconducting coil. The excitation device, space for a superconducting magnet apparatus according to any one of 0 claims 1 1, characterized in that it comprises a second solar cell electrically connected to the current lead. The excitation device includes a power supply circuit that has an input end electrically connected to the second solar cell and an output end electrically connected to the current lead, and controls power supplied to the superconducting coil. The space superconducting magnet apparatus according to claim 15 , wherein The space superconducting magnet device according to any one of claims 1 to 16 ,
A space propulsion device comprising: a plasma generator for expanding a magnetosphere of a magnetic field generated by the space superconducting magnet device.
It is characterized by that.

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