Improved satellite systems

Abstract

A system for generating a magnetic field in one or more axes is provided. The system includes a primary electromagnet including a first coil having a first axis, a first secondary electromagnet including a second coil having a second axis, and a second secondary electromagnet including a third coil having a third axis. The first, second, and third axes are non-parallel, and the first, second, and third coils are formed of a superconductor. The system includes a cooling element configured to cool the first, second, and third coils below a critical temperature of the superconductor, and a power supply configured to provide power to the primary and secondary electromagnets.

Description

[Technical Field]

[0001] The present invention relates to systems for generating magnetic fields in one or more axes. More particularly, but not exclusively, the present invention relates to magnetic position control systems useful, for example, for controlling satellites. [Background technology]

[0002] Superconducting electromagnets, such as high-temperature superconducting (HTS) magnets, are made from coils of superconducting wire. Such magnets may be desirable for use in satellite positioning because, in their superconducting state, the electromagnet's wire has zero electrical resistance, allowing them to carry much larger currents than ordinary wire, generate powerful magnetic fields, and be cheaper to operate in terms of energy consumption. However, such magnets must be cooled below their critical temperature, the temperature at which the HTS material changes from its normal resistive state and becomes a superconductor. Solutions for effectively and efficiently cooling superconducting electromagnets to enable their more widespread and effective use in satellite environments have not been thoroughly explored.

[0003] One common method of cooling superconducting electromagnets is to use liquid helium as a coolant to cool the electromagnet's superconducting windings. Typically, both the electromagnet and the coolant are contained within an insulated vessel. To prevent the helium from boiling, the vessel is usually constructed with an external jacket containing liquid nitrogen. However, this cooling method is undesirable for cooling electromagnets configured for use on satellites due to the harsh conditions of outer space. Using such an external jacket containing liquid nitrogen can significantly increase the volume, mass, and complexity of the satellite, which is undesirable.

[0004] Thus, with respect to superconducting electromagnets configured for use on satellites, the aspect of effectively cooling the superconducting electromagnet and also maintaining the thermal mass at cryogenic temperatures (i.e., below the superconducting critical temperature) has not been adequately addressed until now.

[0005] One or more of the above limitations and drawbacks may also apply to other spacecraft that use magnetic fields for position control. Summary of the Invention [Problem to be solved by the invention]

[0006] It is an object of the present invention to provide a magnetic attitude control system that overcomes or at least partially ameliorates some of the above limitations or drawbacks, or at least provides the public with a useful choice.

[0007] Alternatively and / or additionally, it is an object of the present invention to provide a spacecraft that overcomes or at least partially ameliorates some of the above limitations or disadvantages, or at least provides the public with a useful choice.

[0008] Alternatively and / or additionally, it is an object of the present invention, but not limited to, to provide one or more components or parts of a satellite or other spacecraft positioning system, such as an electromagnetic positioning system, that overcomes or at least partially ameliorates some of the above limitations or disadvantages, or at least provides the public with a useful option. [Means for solving the problem]

[0009] In a first aspect, the present invention can broadly reside in a system for generating a magnetic field in one or more axes. The system includes a first electromagnet including a first coil having a first axis, a first secondary electromagnet including a second coil having a second axis, and a second secondary electromagnet including a third coil having a third axis. The first, second, and third axes are non-parallel, and the first, second, and third coils are formed of a superconductor. The system includes a cooling element configured to cool the first, second, and third coils below a critical temperature of the superconductor, and a power source configured to provide power to the primary and secondary electromagnets.

[0010] In a second aspect, the present invention can broadly reside in a system for generating a magnetic field in one or more axes. The system includes a primary electromagnet including a first coil having a first axis, a first secondary electromagnet including a second coil having a second axis, and optionally a second secondary electromagnet including a third coil having a third axis. The first, second, and third axes are non-parallel, and the first, second, and third coils are formed of a superconductor. The system includes a cooling element configured to cool the first, second, and third coils below a critical temperature of the superconductor, and a power source configured to provide power to the primary and secondary electromagnets.

[0011] In one embodiment, two of the first, second, and third axes are orthogonal.

[0012] In one embodiment, the first, second, and third axes are orthogonal.

[0013] In one embodiment, the first coil is a pancake coil.

[0014] In one embodiment, the primary electromagnet further includes a frame member having an inner periphery and an outer periphery, and the first coil is wound around the outer periphery of the frame member.

[0015] In one embodiment, the secondary electromagnet is attached to a frame member of the primary electromagnet.

[0016] In one embodiment, the secondary electromagnet is mounted within the inner periphery of the frame member.

[0017] In one embodiment, the secondary electromagnet is positioned inside the inner periphery of the frame member.

[0018] In one embodiment, the secondary electromagnet is positioned inside the footprint of the primary electromagnet.

[0019] In one embodiment, the secondary electromagnets are not located outside the footprint of the primary electromagnets.

[0020] In one embodiment, the secondary electromagnet is positioned within the thickness of the primary electromagnet.

[0021] In one embodiment, the secondary electromagnet does not extend outside the thickness of the primary electromagnet.

[0022] In one embodiment, the secondary electromagnet extends coplanar with the plane of the primary electromagnet.

[0023] In one embodiment, the secondary electromagnet is enclosed within the primary electromagnet.

[0024] In one embodiment, the secondary electromagnets are each provided in the form of a solenoid.

[0025] In one embodiment, the system further includes a third secondary electromagnet including a fourth coil having a fourth axis and a fourth secondary electromagnet including a fifth coil having a fifth axis, wherein the fourth coil and the fifth coil are formed of a superconductor, and the cooling element is further configured to cool the fourth coil and the fifth coil below a critical temperature of the superconductor.

[0026] In one embodiment, the superconductor is a high temperature superconductor (HTS).

[0027] In one embodiment, the frame members are quadrilateral (preferably rectangular).

[0028] In one embodiment, the frame member is quadrilateral (preferably rectangular) and each of the secondary electromagnets is mounted parallel to each side of the frame member.

[0029] In one embodiment, the frame member is quadrilateral (preferably rectangular), each of the secondary electromagnets is mounted parallel to each side of the frame member, and the fourth axis and fifth axis are parallel to the second axis and third axis, respectively.

[0030] In one embodiment, the frame member is supported by at least one bracket.

[0031] In one embodiment, the frame member is suspended from at least one bracket by an insulating structural member such as a cable or rod.

[0032] In one embodiment, the frame member is suspended from at least one bracket by an insulating damper, such as a spring.

[0033] In one embodiment, the insulating structural member is formed from one of a metallic or non-metallic material including one or more of a polymer, ceramic, composite, glass, Kevlar, stainless steel, or quartz.

[0034] In one embodiment, the frame members are suspended from a plurality of brackets by insulating structural members.

[0035] In one embodiment, the frame member is suspended by the insulating structural member from four brackets, one bracket facing and supporting each corner of the frame member.

[0036] In one embodiment, the bracket includes an adjustable tension adjustment means for adjusting the tension in the insulating structural member.

[0037] In one embodiment, the adjustable tensioning means includes a threaded spool around which the end portion of the insulating structural member is wound.

[0038] In one embodiment, the adjustable tensioning means includes one or more of a spring loaded pulley, a pinion, a roller, and a worm gear.

[0039] In one embodiment, the bracket includes an automatic tensioning means for maintaining tension in the insulating structural member.

[0040] In one embodiment, the bracket is formed from a resilient, flexible material and is configured to provide tension to the insulating structural member through its resilience.

[0041] In one embodiment, the automatic tensioning means includes a spring loaded pulley.

[0042] In one embodiment, the bracket is formed from a metallic or non-metallic material including one or more of a polymer, ceramic, composite, glass, nylon, aluminum, titanium, or PTFE.

[0043] In one embodiment, the cooling element includes a thermal linkage in thermal contact with the heat extraction means.

[0044] In one embodiment, the heat extraction means comprises one of a cryocooler, a heat pump, a heat exchanger, or a heat sink.

[0045] In one embodiment, the heat extraction means is one of a Stirling cryocooler, a pulse tube cryocooler, a pulse tube miniature cryocooler, a Gifford-McMahon cryocooler, a dilution refrigerator, an adiabatic demagnetization refrigerator, or a thermoelectric refrigerator.

[0046] In one embodiment, the heat extraction means comprises a pair of cryocoolers arranged in an opposing geometric arrangement to reduce net vibration during operation.

[0047] In one embodiment, a thermal linkage is disposed between the heat extraction means and the frame member and provides a thermal path between the heat extraction means and each of the coils of the primary and secondary electromagnets.

[0048] In one embodiment, the thermal linkage includes a flexible connector that may be made from one or more of braided copper, aluminum, or graphene.

[0049] In one embodiment, the power source includes an electromagnetic flux injection device.

[0050] In one embodiment, the electromagnetic flux injector is an electromagnetic flux pump.

[0051] In one embodiment, the electromagnetic flux pump is contactless.

[0052] In one embodiment, the system further includes a thermal insulating material positioned to reduce radiative heat transfer between the primary and secondary electromagnets and their surrounding environment.

[0053] In a third aspect, the invention may broadly reside in a system for generating a magnetic field in one or more axes, the system including: a primary electromagnet including a first coil having a first axis, the first coil formed of a superconductor; a cooling element configured to cool the first coil below a critical temperature of the superconductor; and a power source configured to provide power to the primary electromagnet, the primary electromagnet including a frame member, the frame member suspended from at least one bracket by a thermally insulated structural member.

[0054] In one embodiment, the insulating structural member is formed from any metallic or non-metallic material including one or more of a polymer, ceramic, composite, glass, Kevlar, stainless steel, or quartz.

[0055] In one embodiment, the frame members are rectangular in shape.

[0056] In one embodiment, the frame members are rectangular.

[0057] In one embodiment, the frame members are suspended from a plurality of brackets by insulating structural members.

[0058] In one embodiment, the frame member is rectangular and is suspended by the insulating structural member from four brackets, one bracket facing and supporting each corner of the frame member.

[0059] In one embodiment, the bracket includes an adjustable tension adjustment means for adjusting the tension in the insulating structural member.

[0060] In one embodiment, the adjustable tensioning means includes a threaded spool around which the end of the insulating structural member is wound.

[0061] In one embodiment, the adjustable tensioning means includes one or more of a spring loaded pulley, a pinion, a roller, and a worm gear.

[0062] In one embodiment, the bracket includes an automatic tensioning means for maintaining tension in the insulating structural member.

[0063] In one embodiment, the bracket is formed from a resilient, flexible material and is configured to apply tension to the insulating structural member through its resilience.

[0064] In one embodiment, the automatic tensioning means includes a spring loaded pulley.

[0065] In one embodiment, the bracket is formed from a metallic or non-metallic material including one or more of a polymer, ceramic, composite, glass, nylon, aluminum, titanium, or PTFE.

[0066] In one embodiment, a first secondary electromagnet is attached to a frame member including a second coil having a second axis, the second coil being formed from a superconductor; the first axis and the second axis are non-parallel; The cooling element is further configured to cool the second coil below the critical temperature of the superconductor.

[0067] In one embodiment, a second secondary electromagnet is attached to a frame member including a third coil having a third axis, the third coil being formed from a superconductor; the first, second, and third axes are non-parallel; The cooling element is further configured to cool the third coil below the critical temperature of the superconductor.

[0068] In one embodiment, two of the first, second, and third axes are orthogonal.

[0069] In one embodiment, the first, second, and third axes are orthogonal.

[0070] In one embodiment, the first coil is a pancake coil.

[0071] In one embodiment, the frame member has an inner periphery and an outer periphery, and the first coil is wound around the outer periphery of the frame member.

[0072] In one embodiment, the secondary electromagnet is mounted within the inner periphery of the frame member.

[0073] In one embodiment, the secondary electromagnets are each provided in the form of a solenoid.

[0074] In one embodiment, there are multiple cooling elements.

[0075] In a fifth aspect, the present invention may broadly reside in a method of generating a magnetic field in one or more axes, the method including the steps of: providing a primary electromagnet including a first coil having a first axis, providing a first secondary electromagnet including a second coil having a second axis, and optionally providing a second secondary electromagnet including a third coil having a third axis, the first, second, and third axes being non-parallel and the first, second, and third coils being formed of a superconductor; providing a cooling element and using the electromagnet to cool the first coil and the second coil (and optionally the third coil) below a critical temperature of the superconductor; and providing a power source and using the power source to power the primary electromagnet and the secondary electromagnet.

[0076] In a sixth aspect, the invention may broadly reside in a spacecraft or satellite incorporating a system as described in any one or more of the above statements.

[0077] In one embodiment, a satellite or spacecraft can control its orientation about one or more axes of rotation using the above-described systems located on the satellite or spacecraft.

[0078] In one embodiment, the satellite or spacecraft can control its orientation about three axes of rotation using the aforementioned systems located on the satellite or spacecraft.

[0079] In embodiments that control orientation about more than one axis of rotation, at least two of the axes are not parallel to one another.

[0080] In embodiments that control orientation about three axes of rotation, the three axes are not parallel to one another.

[0081] In embodiments that control orientation about more than one axis of rotation, at least two axes are orthogonal to each other.

[0082] In embodiments that control orientation about three axes of rotation, the three axes are mutually orthogonal.

[0083] In embodiments that control orientation about three axes of rotation, at least two of the three axes are orthogonal to one another.

[0084] In one embodiment, the axis corresponds to the axis of an electromagnet.

[0085] In one embodiment, the axes are each parallel to the axis of the electromagnet.

[0086] In a seventh aspect, the invention may broadly reside in a spacecraft or satellite incorporating a system as set forth in any one or more of the above statements, the satellite or spacecraft including a chassis and a superconducting magnet control system mounted on or within at least a portion of the chassis for positional control of said satellite.

[0087] In one embodiment, the chassis is a frame member.

[0088] In one embodiment, the chassis is a frame member as defined in any description of or in relation to any of the above aspects.

[0089] In one embodiment, the satellite or spacecraft includes at least one superconducting electromagnet.

[0090] In one embodiment, at least one superconducting electromagnet includes or is attached to at least one cooling element.

[0091] In an embodiment, the at least one cooling element is a cooling element as defined in any statement of or in relation to any of the above aspects.

[0092] In one embodiment, the at least one superconducting electromagnet is a primary electromagnet as defined in any statement of or associated with any of the above aspects.

[0093] In an embodiment, the at least one superconducting electromagnet is a first secondary electromagnet as defined in any of the statements of or associated with any of the above aspects.

[0094] In an embodiment, the at least one superconducting electromagnet is a second secondary electromagnet as defined in any of the statements of or related to any of the above aspects.

[0095] In one embodiment, the satellite or spacecraft includes at least one cryocooler.

[0096] In one embodiment, the at least one cryocooler is thermally coupled to the at least one cooling element and cools the at least one superconducting electromagnet or at least one or more components thereof via the at least one cooling element.

[0097] In one embodiment, at least one cryocooler is thermally coupled to at least one cooling element and cools at least one superconducting electromagnet or at least one or more components thereof via the at least one cooling element by conduction cooling or conduction cooling alone.

[0098] In one embodiment, at least one cryocooler is thermally coupled to at least one cooling element to cool the at least one cooling element, and when the at least one cooling element is at a lower temperature than the superconducting electromagnet or at least one or more components thereof, conductive cooling of the superconducting electromagnet or at least one or more components thereof occurs by heat transfer through the at least one cooling element.

[0099] In one embodiment, the at least one cooling element is a cooling plate.

[0100] In one embodiment, the at least one cooling element is a metallic or non-metallic cooling plate.

[0101] In one embodiment, the at least one superconducting electromagnet is thermally coupled to the at least one cryocooler by at least one heat strap.

[0102] In one embodiment, the at least one superconducting electromagnet is thermally coupled to the at least one cryocooler by at least one metallic link.

[0103] In one embodiment, at least one cooling element is made of copper.

[0104] In one embodiment, the at least one superconducting electromagnet is a high temperature superconductor (HTS) electromagnet.

[0105] In one embodiment, the at least one HTS electromagnet has at least one magnetically permeable core.

[0106] In one embodiment, the at least one magnetically permeable core has a higher relative magnetic permeability than a conventional core, such as an iron core.

[0107] In one embodiment, at least one magnetically permeable core has a relative magnetic permeability greater than 500.

[0108] In one embodiment, the at least one superconducting electromagnet includes at least one coil, and the at least one cooling plate is in thermal contact with the at least one coil.

[0109] In one embodiment, the at least one superconducting electromagnet includes at least one coil, and the at least one superconducting electromagnet includes or is attached to at least two cooling elements in thermal contact with the at least one coil, the cooling elements being an upper cooling element and a lower cooling element, and the at least one coil is sandwiched between the upper cooling element and the lower cooling element.

[0110] In an embodiment, the at least one coil is a first coil, a second coil, and / or a third coil as defined in any of the statements of or associated with any of the above aspects.

[0111] In one embodiment, the upper cooling element is an upper cooling plate.

[0112] In one embodiment, the lower cooling element is a lower cooling plate.

[0113] In one embodiment, at least one of the upper cooling element and the lower cooling element is substantially hexagonal in shape.

[0114] In one embodiment, at least one of the upper and lower cooling elements is made of copper.

[0115] In one embodiment, at least one of the upper and lower cooling elements is 2 mm thick.

[0116] In one embodiment, at least one of the upper and lower cooling elements includes six holes, preferably six 3 mm holes with a diameter of 66 mm.

[0117] In one embodiment, the superconducting electromagnet includes two pole pieces with the magnetic field sensor sandwiched between the pole pieces.

[0118] In one embodiment, a thermal linkage is provided between the upper and lower cooling elements to thermally couple the upper and lower cooling elements.

[0119] In one embodiment, at least one coil is an HTS coil based on yttrium barium copper oxide (YBCO) 2G (second generation).

[0120] In one embodiment, at least one coil is made from tape or wire that is approximately 100 m long, 3 mm wide, and 50 μm thick.

[0121] In one embodiment, at least one coil has an outer diameter of 60 mm.

[0122] In one embodiment, at least one coil uses about 100 m of tape and is dry wound without inter-turn insulation or embedded in a matrix with insulation.

[0123] In one embodiment, the at least one superconducting electromagnet further includes a cylindrical magnet bore.

[0124] In one embodiment, the cylindrical magnet bore has an outer diameter of about 10 mm and an inner diameter of about 8 mm.

[0125] In one embodiment, at least one coil is wound around a cylindrical magnet bore.

[0126] In one embodiment, at least one coil is a double pancake coil.

[0127] In one embodiment, the double pancake coil is an HTS wire double pancake coil.

[0128] In one embodiment, the double pancake coil is an HTS wire double pancake coil based on yttrium barium copper oxide (YBCO) 2G (second generation).

[0129] In one embodiment, an insulating sheet is provided between the at least one coil and the cooling element to reduce electrical short circuits.

[0130] In one embodiment, the insulating sheet is a G10 insulating sheet.

[0131] In one embodiment, the winding of at least one coil terminates in a current bus.

[0132] In one embodiment, thermal grease is applied to each thermal interface of at least one superconducting electromagnet.

[0133] In one embodiment, the at least one superconducting electromagnet includes at least one yoke plate attached to an outer surface of at least one of the upper cooling element and the lower cooling element.

[0134] In one embodiment, at least one yoke plate is a mild steel yoke plate.

[0135] In one embodiment, at least one yoke plate is a mild steel magnetic yoke plate.

[0136] In one embodiment, the at least one yoke plate is screwed or lightly screwed to at least one of the upper cooling element and the lower cooling element.

[0137] In one embodiment, fastening means are provided for firmly clamping the upper and lower cooling elements into thermal contact with the at least one coil.

[0138] In one embodiment, the fastening means is one or more brackets.

[0139] In one embodiment, the bracket or brackets are made of stainless steel.

[0140] In one embodiment, the at least one cryocooler is selected from a Stirling cryocooler, a pulse tube tactical cryocooler, or a pulse tube miniature tactical cryocooler.

[0141] In one embodiment, the superconducting magnet control system comprises: at least one power source; at least one controller; The at least one cryocooler is operably coupled to at least one controller and at least one power source, and based on a control signal from the controller, the at least one cryocooler is configured to draw energy from the at least one power source to cool the at least one superconducting electromagnet or at least one or more components thereof.

[0142] In one embodiment, the satellite or spacecraft further includes a set of reaction wheels operably coupled to the at least one power source and the at least one controller.

[0143] In an embodiment, the at least one power source is a power source as defined in any of the statements of or associated with any of the above aspects.

[0144] In one embodiment, the set of reaction wheels includes three reaction wheels.

[0145] In one embodiment, the pair of reaction wheels are orthogonal to each other.

[0146] In one embodiment, a set of reaction wheels draws energy from at least one power source.

[0147] In one embodiment, the operation of the set of reaction wheels is controlled by at least one controller.

[0148] In one embodiment, the at least one controller includes an on-board computer.

[0149] In one embodiment, the at least one controller includes a microprocessor.

[0150] In one embodiment, the microprocessor is a programmable microprocessor.

[0151] In one embodiment, the at least one controller includes a control board.

[0152] In one embodiment, the at least one controller draws energy from at least one power source.

[0153] In one embodiment, the at least one controller is configured to control at least one of the timing, magnitude, and polarity of the magnetic field within the at least one superconducting electromagnet.

[0154] In one embodiment, the at least one controller is configured to control timing of the at least one cryocooler to cool the at least one superconducting electromagnet.

[0155] In one embodiment, at least one cryocooler is controlled by at least one controller and draws energy from at least one power supply to cool at least one superconducting electromagnet.

[0156] In one embodiment, the at least one power source includes at least one solar panel.

[0157] In one embodiment, the at least one power source is a battery.

[0158] In one embodiment, the battery is a rechargeable battery.

[0159] In one embodiment, the at least one power source is a capacitor.

[0160] In one embodiment, the superconducting magnet control system further includes at least one electromagnetic flux injector operably coupled to the at least one controller and configured to draw energy from the at least one power source to excite the at least one superconducting electromagnet.

[0161] In one embodiment, at least one electromagnetic flux injector is controlled by at least one controller and draws energy from at least one power source to energize at least one superconducting electromagnet.

[0162] In one embodiment, the at least one electromagnetic flux injector is an electromagnetic flux pump.

[0163] In one embodiment, the at least one electromagnetic flux pump is a linear magnetic flux pump.

[0164] In one embodiment, the at least one electromagnetic flux pump is contactless.

[0165] In one embodiment, the at least one electromagnetic flux pump includes a plurality of solenoids.

[0166] In one embodiment, the at least one electromagnetic flux pump includes a copper solenoid with an iron core or multiple solenoids, each solenoid having a copper coil with an iron core.

[0167] In one embodiment, the iron core of each of the plurality of solenoids extends between a first end portion and a second end portion, each first end portion is attached to a common iron frame having a plurality of cubic iron pieces, and each second end portion is attached to a cubic piece independent of the plurality of cubic iron pieces.

[0168] In one embodiment, the frame is square or substantially square having a first side, a second side, a third side, and a fourth side, the first side being opposite the third side and the second side being opposite the fourth side.

[0169] In one embodiment, at least one electromagnetic flux pump includes six solenoids, three solenoids having a first end portion of an iron core attached to a first side of a frame, and three solenoids having a first end portion of an iron core attached to a third side of the frame, with the cube pieces attached to the second end portions spaced apart from one another.

[0170] In one embodiment, the at least one electromagnetic flux pump is a non-linear magnetic flux pump.

[0171] In one embodiment, the at least one electromagnetic flux pump includes a permanent magnet.

[0172] In one embodiment, the at least one electromagnetic flux pump is located remotely from the at least one superconducting electromagnet.

[0173] In one embodiment, the at least one electromagnet is mounted to the satellite or spacecraft chassis but is located at a distance from the at least one superconducting electromagnet.

[0174] In one embodiment, the electromagnetic flux pump is configured to magnetize at least one coil, the at least one coil being an HTS coil or an HTS tape.

[0175] In one embodiment, the chassis is in the shape of a hollow cube or rectangular parallelepiped that includes multiple walls.

[0176] In one embodiment, at least one superconducting electromagnet is disposed on at least one wall.

[0177] In one embodiment, the satellite or spacecraft has a total mass of at least 500 kg or more.

[0178] In one embodiment, the total mass of the satellite or spacecraft is less than 500 kg.

[0179] In one embodiment, the satellite is a pico-satellite or a nano-satellite.

[0180] In one embodiment, the satellite is a CubeSat (U-class spacecraft) that includes at least one unit.

[0181] In one embodiment, the satellite includes two or more units adjacent to each other.

[0182] In one embodiment, the chassis includes a frame structure formed by four spaced apart substantially vertical rails and four spaced apart substantially horizontal rails, the frame structure having a cross section in a plane perpendicular to a longitudinal axis of each of the substantially vertical rails in the shape of a four-sided polygon; In the frame structure, each of the four substantially vertical rails is connected to two of the other three substantially vertical rails via two of the substantially horizontal rails that are substantially vertically spaced apart from one another and substantially perpendicular to one another.

[0183] In one embodiment, the shape of the four-sided polygon is a square or a rectangle.

[0184] In one embodiment, the substantially vertical rail and the substantially horizontal rail are integrally formed.

[0185] In one embodiment, each substantially vertical rail includes a first end portion and a second end portion and extends longitudinally from the first end portion to the second end portion, and in each substantially vertical rail, one of the substantially horizontal rails is located at or proximate to the first end portion and another of the substantially horizontal rails is located at or proximate to the second end portion.

[0186] In one embodiment, at least a portion of each substantially vertical rail is L-shaped in cross section in a plane perpendicular to the longitudinal axis of that vertical rail.

[0187] In one embodiment, each substantially vertical rail includes a first end portion and a second end portion and extends longitudinally from the first end portion to the second end portion, and in each substantially vertical rail, one of the substantially horizontal rails is located at or proximate to the first end portion and another of the substantially horizontal rails is located at or proximate to the second end portion.

[0188] In one embodiment, at least one of the first end portion and the second end portion of each substantially vertical rail includes a plate member.

[0189] In one embodiment, the plate member is integrally formed with a substantially vertical rail.

[0190] In one embodiment, the four substantially perpendicular rails are the same length.

[0191] In one embodiment, at least one of the substantially vertical rails has a plurality of spaced openings along its length.

[0192] In one embodiment, the plurality of spaced apart openings are configured to accommodate countersunk head screws.

[0193] In one embodiment, the four substantially horizontal rails are the same length.

[0194] In one embodiment, the interior volume of the chassis is a cube or rectangular parallelepiped.

[0195] In one embodiment, the chassis is constructed from a rigid material.

[0196] In one embodiment, the chassis is constructed from 3D printed titanium.

[0197] In one embodiment, the satellite or spacecraft is configured for use in a magnetic field.

[0198] In one embodiment, the magnetic field is a natural or artificial magnetic field.

[0199] In one embodiment, the magnetic field is the natural magnetic field of the Earth or celestial bodies.

[0200] In one embodiment, the magnetic field is the magnetic field of at least one other satellite or spacecraft.

[0201] In one embodiment, a satellite or spacecraft can control its orientation about at least two axes of rotation using the aforementioned systems located on the satellite or spacecraft.

[0202] In one embodiment, the satellite or spacecraft can control its orientation around three axes of rotation using the aforementioned systems located on the satellite or spacecraft.

[0203] In one embodiment, at least two axes are not parallel to each other.

[0204] In one embodiment, the three axes are not parallel to one another.

[0205] In one embodiment, at least two axes are orthogonal to each other.

[0206] In one embodiment, the three axes are orthogonal to one another.

[0207] In one embodiment, at least two of the three axes are orthogonal to one another.

[0208] In one embodiment, the axis corresponds to the axis of an electromagnet.

[0209] In one embodiment, the axes are each parallel to the axis of the electromagnet.

[0210] In an eighth aspect, the invention broadly resides in a spacecraft or satellite incorporating a system as described in any one or more of the above statements, the spacecraft or satellite being as disclosed in PCT International Publication No. WO2020 / 174378A1.

[0211] In a ninth aspect, the invention relates to a satellite or spacecraft whose orientation can be controlled around at least two axes of rotation using a system as described above installed on the spacecraft.

[0212] In one embodiment, at least two axes are not parallel to each other.

[0213] In one embodiment, at least two axes are orthogonal to each other.

[0214] In one embodiment, the axis corresponds to the axis of an electromagnet.

[0215] In a tenth aspect, the invention resides in a satellite or spacecraft whose orientation can be controlled around three axes of rotation using the aforementioned system installed on the satellite or spacecraft.

[0216] In one embodiment, the three axes are not parallel to one another.

[0217] In one embodiment, the three axes are orthogonal to one another.

[0218] In one embodiment, at least two of the three axes are orthogonal to one another.

[0219] In one embodiment, the axis corresponds to the axis of an electromagnet.

[0220] In the above, one or more statements of or relating to one embodiment may apply to other embodiments as well.

[0221] Other aspects of the present invention may become apparent from the following description, given by way of example only, with reference to the accompanying drawings.

[0222] This specification may refer to patent specifications, other external documents, or other sources of information, generally for the purpose of providing a context for discussing features of the present invention. Unless specifically stated otherwise, a reference to such external documents should not be construed as an admission that such documents or such sources are prior art in any jurisdiction or form part of the general common general knowledge in the art.

[0223] For purposes of this specification, when method steps are described in a sequential order, that order does not necessarily imply that the steps are chronologically arranged in that order, unless there is no other logical way to interpret the order.

[0224] For purposes of the following description, the terms "top," "bottom," "right," "left," "vertical," "horizontal," "upper," "lower," "sideways," "vertical," and derivatives thereof, shall refer to the invention as shown in the orientation of the drawings. It is understood, however, that the invention may assume various alternative variations unless expressly specified to the contrary. It is also understood that the specific devices illustrated in the accompanying drawings and described in the following description are merely exemplary embodiments of the invention. As such, specific dimensions and other physical characteristics related to the embodiments disclosed herein are not to be considered limiting.

[0225] It is recognized that the term "comprise" may have an exclusive or inclusive meaning in different jurisdictions. For purposes of this specification, unless specifically stated otherwise, the term "comprise" shall have an inclusive meaning, that is, be interpreted to include not only the directly referenced listed component, but also other unspecified components or elements. This rationale also applies when the term "comprise, having, comprising" is used in connection with an apparatus or one or more steps of a method or process.

[0226] As used above and below, the term "and / or" means "and" or "or", or both.

[0227] As used above and below, "plural(s)" refers to the plural and / or singular form of a noun.

[0228] When used in the claims, unless expressly specified otherwise, the word "for" is to be construed only to mean "suitable for," and not, for example, specifically "adapted for" or "configured for" a recited purpose.

[0229] As used hereinbefore and hereinafter, unless otherwise specified, the term "satellite" shall be taken to mean an artificial satellite, i.e., an artificial satellite.

[0230] As used herein above and below, unless otherwise specified, the term "conduction cooling" means cooling using heat transfer through a conductive element (i.e., a cooling element) in direct contact with the component to be cooled, the conductive element being thermally coupled to a cryocooler for cooling the conductive element, and the term "conduction cooling" excludes other alternative cooling techniques other than "conduction cooling."

[0231] As used herein above and hereinafter, unless otherwise specified, the term "position control" shall be construed to mean attitude control, altitude control, and / or relative position control of a satellite using that satellite's electromagnetic control system (i.e., relative position control using the magnetic fields of nearby satellites).

[0232] The term "cooling element" as used herein above and hereinafter, unless otherwise specified, is taken to mean a heat conducting element suitable for use in conduction cooling.

[0233] It is recognized that the term "substantially" can be used to broaden a term in some cases. It should be clarified that, in this specification, when the term "substantially" is used in conjunction with a term to define a distinctive feature, all of the benefits of using the term "substantially" (i.e., the benefits of the broadening) are obtained, and that the exact same feature (without the broadening) is also included within its scope. For example, if a feature is described / defined herein as "substantially vertical," the scope includes features that are "close" to vertical (the term "substantially" is considered to be an extension of the term "vertical"), and also includes features that are "exactly" vertical.

[0234] The present invention may be broadly described as consisting of the parts, elements, features, and any two or more or all combinations of parts, elements, features individually or collectively referred to or shown in the specification of this application, and where certain wholes for which equivalents are known in the art to which the present invention pertains are referred to herein, such known equivalents are deemed to be incorporated herein as if individually set forth. [Brief explanation of the drawings]

[0235] The present invention will now be described, by way of example only, with reference to the drawings in which: [Figure 1] The coordinate system is shown, with points O and P indicating the location of the center of the Earth's magnetic dipole and the center of the onboard magnetic dipole generated by the HTS electromagnet. [Figure 2] 1 shows the closed loop and closed region used to calculate the magnetic moment. [Figure 3] 1 illustrates an isometric view of a magnetic attitude adjustment system according to an embodiment of the present invention. [Figure 4] 1A and 1B show top and side views of a system according to one embodiment of the present invention. [Figure 5] 1 illustrates an isometric view of certain components of a system according to one embodiment of the present invention. [Figure 6] 1 shows an isolated isometric view of a bracket according to one embodiment of the present invention. [Figure 7]10 illustrates various adjustment mechanisms for a suspension system according to one embodiment of the present invention. [Figure 8] 10A-10C illustrate various configurations of a suspension system according to one embodiment of the present invention. [Figure 9] 1 illustrates various arrangements of electromagnetic coils according to various embodiments of the present invention. [Figure 10] 1 illustrates various arrangements of electromagnetic coils according to various embodiments of the present invention. [Figure 11] 1 illustrates various arrangements of electromagnetic coils according to various embodiments of the present invention. [Figure 12] 1 illustrates various arrangements of electromagnetic coils according to various embodiments of the present invention. [Figure 13] 1 illustrates various arrangements of electromagnetic coils according to various embodiments of the present invention. [Figure 14] 1 illustrates various arrangements of electromagnetic coils according to various embodiments of the present invention. [Figure 15] 1 illustrates various arrangements of electromagnetic coils according to various embodiments of the present invention. [Figure 16] 1 illustrates various arrangements of electromagnetic coils according to various embodiments of the present invention. [Figure 17] 1 illustrates various arrangements of electromagnetic coils according to various embodiments of the present invention. [Figure 18] 1 illustrates various arrangements of electromagnetic coils according to various embodiments of the present invention. [Figure 19] 1 illustrates various arrangements of electromagnetic coils according to various embodiments of the present invention. [Figure 20] 1 illustrates various arrangements of electromagnetic coils according to various embodiments of the present invention. [Figure 21] 1 illustrates various arrangements of electromagnetic coils according to various embodiments of the present invention. [Figure 22] 1 illustrates various arrangements of electromagnetic coils according to various embodiments of the present invention. [Figure 23] 1 illustrates various arrangements of electromagnetic coils according to various embodiments of the present invention. [Figure 24] 1 illustrates various arrangements of electromagnetic coils according to various embodiments of the present invention. [Figure 25]1 illustrates various arrangements of electromagnetic coils according to various embodiments of the present invention. [Figure 26] 1 illustrates various arrangements of electromagnetic coils according to various embodiments of the present invention. [Figure 27] 1 illustrates various arrangements of electromagnetic coils according to various embodiments of the present invention. [Figure 28] 1 illustrates various arrangements of electromagnetic coils according to various embodiments of the present invention. [Figure 29] 1 illustrates various arrangements of electromagnetic coils according to various embodiments of the present invention. [Figure 30] 1 illustrates various arrangements of electromagnetic coils according to various embodiments of the present invention. [Figure 31] 1 illustrates various arrangements of electromagnetic coils according to various embodiments of the present invention. [Figure 32] 1 illustrates various arrangements of electromagnetic coils according to various embodiments of the present invention. [Figure 33] 1 illustrates various arrangements of electromagnetic coils according to various embodiments of the present invention. [Figure 34] 1 illustrates various arrangements of electromagnetic coils according to various embodiments of the present invention. [Figure 35] 1 illustrates various arrangements of electromagnetic coils according to various embodiments of the present invention. [Figure 36] 1 illustrates various arrangements of electromagnetic coils according to various embodiments of the present invention. [Figure 37] 1 illustrates various arrangements of electromagnetic coils according to various embodiments of the present invention. [Figure 38] 1 illustrates various arrangements of electromagnetic coils according to various embodiments of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0236] In the following description, unless otherwise specified, a satellite also refers to a satellite system, and therefore the terms "satellite" and "satellite system" may be used interchangeably herein.

[0237] Magnetic propulsion systems are based on the direct interaction of an object's own magnetic field with an external non-uniform magnetic field, such as the Earth's magnetic field.

[0238] The forces resulting from dipole-dipole interactions are fundamental to magnetic propulsion systems.

[0239] In the solar system, the Sun, as well as many other objects, possess natural magnetic fields. Some of these fields can be used for satellite propulsion, depending on their strength. Low-thrust propulsion can be achieved with any non-uniform external magnetic field, no matter how small. However, strong, dipole-like fields are preferred.

[0240] The Earth's magnetic field is relatively well understood. Although complex, the geomagnetic field can be well approximated by a dipole magnetic field (Walt, Martin (1994)). Introduction to Geomagnetically Trapped Radiation New York, NY: Cambridge University Press pp. 29-33, the entire text of which is incorporated herein by reference).

[0241] In its simplest form, a magnetic propulsion system consists of a solenoid, which creates a magnetic dipole onboard.

[0242] The coordinate system is defined in Figure 1, where points O and P indicate the location of the center of the Earth's magnetic dipole and the location of the center of the magnetic dipole of the onboard solenoid (which coincides with the onboard dipole), respectively.

[0243] Dipole Bond The electrodynamic force resulting from the dipole-dipole interaction is radial F R and the tangential direction F θ The magnitudes of these components can be numerically estimated by Equations 1 and 2 (Pulatov, V. (2001). Magnetic propulsion systems Progress in Aerospace Sciences 37, 245-261, which is incorporated herein by reference in its entirety):

number

[0244] Propulsion system magnetic moment M P is determined by the characteristics of the solenoid and its current I according to equation 3 below:

number

[0245] magnetic moment A solenoid is always subjected to an electrodynamic torque, which is expressed in Equation 4:

number

[0246] The radial force F acting on the solenoid at the equilibrium position R is directed towards O (the center of the Earth). However, the tangential force F θ The direction of is position dependent. It can be positive (in line with the velocity) in the first (I) and third (III) quarters (see Figure 1) and negative (against the velocity) in the second (II) and fourth (IV) quarters, or vice versa, depending on the direction of the orbital motion.

[0247] superconductivity Harnessing the phenomenon of superconductivity allows for the generation of stronger on-board magnetic fields at lower energy costs.

[0248] From equations 1-3 above, we can see that the magnitude of the force generated is directly proportional to the magnitude of the current I. Modern high-temperature superconducting wires can carry currents up to 540 amperes / cm. Such currents can be maintained within the solenoid for years with little or no energy input. To maintain these properties, the wire must reach its threshold superconducting temperature, T C , critical current density J C , and magnetic field density B C be kept lower.

[0249] Superconducting temperature threshold T C is specific to the choice of material, but other critical values ​​of J C (critical current density) and B C (critical magnetic field density) depends on the operating temperature according to Equations 5 and 6 (Dadhich, A. & Schaffner, G. (2016). Electromagnetic Propulsion system for spacecrafts using geomagnetic fields and superconductors, San Diego, 4-8 January, incorporated herein by reference in its entirety).

number

[0250] Electromagnetic control systems can be used for satellite position control. Position control can include attitude control, altitude control, and / or relative position control (i.e., relative position control using the magnetic fields of nearby satellites). Such satellites utilize coils of wire attached to them to pass electrical currents that induce magnetic fields that interact with the magnetic fields of the Earth or other celestial bodies, or nearby satellites, to control the satellite's position in space. The present invention involves the use of superconducting electromagnets maintained in a temperature range where superconductivity occurs. Thus, once current is initiated through the coils or loops of the electromagnet, the current continues to flow through the superconducting material, requiring little or no additional energy.

[0251] The lack of an atmosphere means that there are no elements in outer space that can freeze onto a cryocooler, so it is suitable to use a cryocooler thermally coupled to an electromagnet to keep the electromagnet or electromagnet coils cold enough to become superconducting.

[0252] A small satellite is a satellite with a mass of 500 kg or less.

[0253] The demand for greater and more sustainable maneuverability is driven by the need for controlled deorbit from higher orbits, control of satellite orientation for communications or Earth observation, synchronization of satellite positions in constellations, orbital corrections, in-orbit assembly of complex satellites, proximity operations, etc.

[0254] It is desirable to provide maneuverability for satellites, such as small satellites, that require small, yet relatively high magnetic field electromagnets. It is desirable to design and construct superconducting electromagnets, such as high temperature superconducting (HTS) wire, that offer the possibility of achieving the required magnetic fields in a satellite environment.

[0255] Some examples / embodiments of or for use in the present invention will now be described.

[0256] 3 and 4 illustrate a magnetic position control system 10 according to one embodiment of the present invention. A primary superconducting electromagnet is formed from a superconducting coil 20 wound around the outer periphery or periphery of a frame member 22, the coil 20 having a characteristic axis 20A.

[0257] In one embodiment, the frame member 22 is formed from a non-magnetic material, such as ceramic or plastic, and the primary electromagnet may be classified as a so-called air-core electromagnet. In a further embodiment, the frame member is formed from a ferromagnetic material, such as iron, nickel, or cobalt, thereby forming the core of the primary electromagnet. Alternatively, other suitable materials may be used. While the frame member 22 is depicted as generally rectangular, it may take any necessary shape dictated by a particular application, including, but not limited to, circular, elliptical, irregular, and square.

[0258] In one embodiment, the conductive coil 20 is formed from Super Power Wire or 2G YBCO HTS tape / wire approximately 100 m long, 2-4 mm wide, and 96 μm thick, producing a coil 20 with a diameter of approximately 60 mm.

[0259] Located along each side of the inner periphery of frame member 22 is one of four secondary superconducting electromagnets, each consisting of an HTS coil wound around a cylindrical or rod-shaped core. In one embodiment, each coil is formed from 2G YBCO HTS tape / wire.

[0260] In yet another embodiment, each coil is wound around a core formed of a ferromagnetic material (such as iron, nickel, and cobalt) or a non-ferromagnetic material (such as plastic or ceramic). In an alternative embodiment, no core is provided. Each secondary electromagnet is formed by a coil 30, 35, 40, 45 having a characteristic axis 30A, 35A, 40A, 45A, respectively.

[0261] In the illustrated embodiment, axes 20A, 30A, and 40A are depicted as being orthogonal to one another, but any non-parallel arrangement that provides a component of the magnetic moment in each of three specific dimensions can be used. Similarly, while only three orthogonally arranged coils 20, 30, and 40 are required to provide six degrees of freedom, in the embodiment shown in FIG. 3, two additional coils 35 and 45 are provided, with their axes 35A and 45A parallel to the axes 30A and 40A of coils 30 and 40. This provides for uniform distribution of mass throughout the system, which is particularly important in satellite applications. In further embodiments, additional secondary electromagnets are provided with additional axes that point outward from the plane defined by the primary electromagnets. In yet other embodiments, only the primary electromagnets are provided alone. Alternatively, the primary electromagnets are provided in combination with only one of the secondary electromagnetic coils 30 and 40. In a particular embodiment, the primary electromagnet is provided by winding a coil 20 around each side arm of the frame member 22, thereby approximating four coils arranged along the edges of a square.

[0262] The particular configuration shown in Figures 3 and 4 uses a combination of so-called pancake coils arranged around four rod coils to provide a magnet configuration that uses minimal space and saves mass while still providing the required three-axis magnetic field.

[0263] Although not shown, it is contemplated that system 10 further includes thermal insulation material positioned to reduce radiative heat transfer between the primary and secondary electromagnets and their surrounding environments.

[0264] Frame member 22 is suspended at each corner by four brackets 60A-D via insulating structural members 65. In one embodiment, structural members 65 are provided in the form of cables. In one embodiment, brackets 60A-D are formed from either nylon, aluminum, titanium, or PTFE, while insulating structural members 65 are formed from either Kevlar®, stainless steel, or plastic, although other suitable materials may be used. In an alternative to the embodiment shown in Figures 3 and 4, frame member 22 is not provided and brackets are used to directly suspend primary electromagnetic coil 20.

[0265] This suspension system thermally isolates the superconducting electromagnetic coils to reduce the thermal load and keep the coils below their critical temperature T C This reduces the cooling time and power required to cool the coil below 1000 kJ / cm2, while insulating the coil from the heat source, thereby reducing the cooling power required to maintain the coil in a superconducting state.

[0266] The suspension system also serves to damp vibrations and external forces (such as those encountered during spacecraft launch) transmitted from the body to the frame members 22.

[0267] Additionally, the open central area and height of the primary magnet allows more space for mounting the cryocooler, suspension system, and power transfer system to the base plate, which reduces the amount of space used in the design and allows for a more compact system, as space is often at a premium on satellites and other spacecraft.

[0268] FIG. 5 shows a further embodiment in which each bracket 60 is provided with two additional horizontally disposed insulating structural members 65 .

[0269] As shown in FIG. 6, each of the four brackets 60A-D is generally V-shaped and has various openings and anchor points 61 through which insulating structural members 65 pass and from which frame members 22 are suspended.

[0270] FIG. 7 illustrates various arrangements of brackets 60A-D and insulating structural members 65, where adjustable and / or automatic tensioning means using one or more tensioning screws 62, spring-loaded pulleys 63, roller pins 64, worm gears 66, and springs 67 are alternatively used to adjust and / or maintain tension applied to the insulating structural members 65 supporting the frame members 22. In the setup shown in FIG. 7A, two tensioning screws 62 are used to tension the insulating structural members 65 in multiple directions. In the setup shown in FIG. 7B, a spring-loaded pulley wheel is used to tension the insulating structural members 65, and this tension can be adjusted by tightening the spring. In the setup shown in FIG. 7C, the tension of the insulating structural members 65 can be adjusted evenly with a single tensioning screw 62.

[0271] In certain embodiments, the brackets 60A-D themselves are formed from a resiliently flexible material and are configured to provide a constant tension to the insulating structural member 65 during assembly, thus reducing the need for mechanical actuation means that may be required to adjust the tension in the structural member. In Figure 7D, screws are inserted into the brackets to selectively adjust the tension in the brackets themselves.

[0272] 8A and 8B show alternative embodiments in which a single U-shaped or square bracket is provided. The operating principle and advantages are the same as above. In the embodiment of FIG. 8A, the insulating structural member 65 is coupled with a spring 67 to increase stiffness and damping.

[0273] 3 and 4 also show a cryocooler 50 positioned in thermal contact with the frame member 22 (and, through the frame member 22, each of the coils 20, 30, 35, 40, and 45) by a thermal linkage 55. In an alternative embodiment, the cryocooler 50 is in direct contact with each of the coils 20, 30, 35, 40, and 45. While the cryocooler 50 is shown as a Stirling cryocooler connected to the thermal linkage by a cold finger 52 or cooling element, other suitable cooling and / or heat extraction means may be used, such as a heat pump, heat exchanger, heat sink, or pulse tube cryocooler, as long as they are capable of extracting heat from the superconducting electromagnet. The absorbed heat is dissipated into the surrounding space via a radiant panel or the like.

[0274] Cryocoolers offer a particularly viable cooling option in satellite environments with relatively small volume and power requirements. Furthermore, the use of cryocoolers eliminates the need for working fluids / sleeves to cool electromagnets and eliminates reliance on consumable cryogenic coolant supplies. In certain embodiments, pulse-tube cryocoolers are used, which offer the added benefit of reduced vibration compared to piston-based cryocoolers.

[0275] In one embodiment, the thermal linkage is provided in the form of a flexible braided copper connector or heat strap. This has been found to provide optimal thermal conduction while remaining resilient to forces experienced during system operation and launch. Furthermore, the use of heat straps is advantageous because it provides a natural conduction path for cooling without imposing structural loads on the satellite components. Heat straps offer reduced mass, size, and superior conductivity compared to traditional thermal solutions. Some heat straps exhibit improved conductivity at cryogenic temperatures, making them effective at dissipating heat from high-power electronic components. In an alternative embodiment, the cold finger 52 of the cryocooler 50 directly contacts the frame member 22, eliminating the need for a heat strap or linkage 55.

[0276] Although not shown, a further embodiment is envisioned that uses a second cryocooler located on the opposite side of cryocooler 50 to counteract axial vibrations imparted to cold finger 52 and thermal linkage 55. A second cryocooler also increases the cooling rate.

[0277] Although not shown in Figures 3 or 4, system 10 further includes a power supply that provides power to the superconducting electromagnets. In one embodiment, this is provided in the form of an electromagnetic flux injector. In a further embodiment, the power supply is provided by one or more non-contact electromagnetic flux pumps, such as linear flux pumps or non-linear flux pumps (using permanent magnets rather than solenoids), that enable wireless and / or inductive power transfer to the superconducting coils.

[0278] During use, the cryocooler 50 raises the temperature of the electromagnetic coils 20, 30, 35, 40, 45 to a critical temperature T C As mentioned above, because superconducting electromagnets have zero electrical resistance, they can carry much larger currents and produce stronger magnetic fields with relatively lower energy consumption than conventional non-superconducting magnetic torque devices.

[0279] This magnetic field can be used to change the position of the spacecraft on which system 10 is installed. Advantageously, high field strength magnetic fields can also be used to deflect incoming charged radiation, thereby protecting both system 10 and the spacecraft (including other spacecraft within the field).

[0280] Once in this superconducting state, the electromagnetic flux injector or electromagnetic flux pump is configured to draw energy from at least one external power source to power the superconducting electromagnet.

[0281] In one embodiment, the electromagnetic flux injector draws power from a battery or solar panel external to the system 10. In one embodiment, the cryocooler 50 and the electromagnetic flux injector are operably coupled to and controlled by a controller. Advantageously, the use of an electromagnetic flux injector, such as a flux pump, to power the electromagnets eliminates the need for high current power supplies, which can be bulky and expensive, as well as the need for physical current supply leads that constantly carry the high current, lossy charging current required in this application.

[0282] A paper on a linear flux pump design that can be used to magnetize HTS tapes and coils is described in Fu, L., Matsuda, K., Baghdadi, M., & Coombs, T. (2015). Linear Flux Pump Device Applied to High Temperature Superconducting (HTS) Magnets. IEEE Transactions on Applied Superconductivity, 25(3), 1-4, which is incorporated herein by reference in its entirety. The design is based on an iron magnetic circuit combined with a copper solenoid and driven by a current source drive circuit.

[0283] 9-38 show several alternative embodiments of the present invention having different arrangements of superconducting electromagnetic coils and cryocooler 50 that allow for multi-axis control.

[0284] In particular, Figure 9 shows a three-part cylindrical rod design containing three electromagnets, each formed from a cylindrical rod containing an iron core and an outer wrapped HTS wire coil.

[0285] Figure 10 shows a pot-core-rod design that includes a semi-hollow rod formed of HTS wire wound inside a small cylindrical iron core that contains an outer cylindrical case. This design has the advantage of reducing electromagnetic interference through the pot-core shielding effect.

[0286] Figure 11 shows a so-called E-core design, which includes a cylindrical center leg and two side legs connected to form an iron core. The center leg contains three axially wound HTS coils.

[0287] Figure 12 shows a so-called U-core rod design: a U- or C-shaped core is provided with an HTS coil wound around a cylindrical plastic bobbin.

[0288] Figure 13 shows a second configuration of the U-shaped core-rod design, further arranging the three cores along three orthogonal axes while using a different geometry.

[0289] Figure 14 shows a design in which multiple small rods are packed together along three directions to distribute the magnetic field more widely.

[0290] Figure 15 shows a design in which multiple small rods are stacked and arranged to provide the desired three-axis magnetic field. This particular configuration allows for a high packing density.

[0291] Figure 16 shows a design using three square pancake coils with copper struts arranged to provide magnetic field components on each of the three axes.

[0292] Figure 17 shows a design using a circular pancake electromagnet.

[0293] Figure 18 shows a design using three orthogonally arranged copper sheets, each fitted with a circular pancake electromagnet.

[0294] Figures 19-27 show various hybrid designs that use both rod and pancake-style electromagnets in multiple combinations and spatial arrangements.

[0295] 28-31 show a further design in which a rod-shaped electromagnet is provided within a volume defined by one or more surrounding pancake-shaped electromagnets.

[0296] 32-34 show configurations of rod-shaped and ring-shaped electromagnets for providing magnetic fields in three axes.

[0297] Figure 35 shows an alternative configuration in which the magnetic components are mounted in the same plane, with two orthogonal rectangular bars protruding from the base plate and the HTS coil wound around the extrusions of the rectangular frame. The cryocooler 50 is mounted within the footprint of the rectangular frame.

[0298] Figure 36 shows a stackable triaxial magnetic structure. Each hexagonal piece consists of two rods in a crossed configuration, while an HTS coil is wound around each hexagon.

[0299] FIG. 37 shows an open frame structure in which a cryocooler 50 can be mounted within an interior volume defined by an electromagnet.

[0300] FIG. 38 illustrates an embodiment in which three electromagnetic coils are arranged in a line, facing each other, with the axes of all three coils perpendicular to one another. Each coil is formed of conductive wire or tape wound around a frame member (101, 102, 103) having an internal volume. In a specific embodiment, the frame members are made of copper to allow rapid heat transfer between the frame members and their respective coils. In an alternative embodiment, the frame members are made of a thermally non-conductive space-grade plastic, such as PEEK (polyetheretherketone), to help insulate the electromagnetic coils and reduce the overall thermal mass of the system 10. In a further embodiment, the frame members are made of aluminum or graphene. However, one skilled in the art will understand that any suitable material may be used for the frame members, including both ferromagnetic materials (such as iron, nickel, and cobalt) and non-ferromagnetic materials (such as plastic or ceramic).

[0301] As shown, the leftmost frame member (101) has a larger inner diameter and a shallower depth than the two frame members (102, 103) to its right, thereby reducing the overall length of the system 10. In alternative embodiments, each frame member is substantially identical in size. While the frame members are depicted as having a generally oval cross-section, one skilled in the art will understand that frame members of any suitable shape may be used depending on the particular application of the system 10.

[0302] In one embodiment, the coils are formed from 2, 4, 6, or 10 mm wide HTS tape / wire. In a further embodiment, each coil is dry wound without inter-turn insulation. In an alternative embodiment, each coil is embedded in a matrix with insulation.

[0303] As shown in the figures, each frame member is connected by a structural member, such as a cross rod (111, 112, 113, 114). In one embodiment, the rods are made of a thermally conductive material, such as copper, and are insulated from the surrounding environment (by insulating mounts, such as plastic bolts, or other suitable forms of insulating breaks), thereby thermally balancing the electromagnets. In one embodiment, the rods are actively cooled by one or more cooling elements (such as cryocooler 50) and are in thermal contact with each frame member and / or individual coil. In one embodiment, thermal contact to the coils is provided by one or more thermal linkages of the type described above. In alternative embodiments, the frame members and / or coils are directly cooled by one or more cooling elements. In certain embodiments, the cooling elements extend through the interior volume of the leftmost frame member (101) in FIG. 38 and contact a plate (not shown) located between the leftmost frame member (101) and the middle frame member (102). This plate is formed of a thermally conductive material, such as copper, and allows the two frame members (101, 102) to be cooled by a single cooling element located within the interior volume of the frame members, thereby reducing the total mass and volume required for system 10. In this embodiment, the right-most frame member (103) can be cooled by the same single cooling element (via a rod or some other thermal linkage between the frame member and one or both of the other frame members and / or cooling elements). Alternatively, the right-most frame member (103) is cooled by a dedicated cooling element.

[0304] Although not shown, the superconducting cooled coils are powered by one or more power sources, such as the electromagnetic flux injectors and non-contact electromagnetic flux pumps discussed above. In certain embodiments, a dedicated flux pump is provided for each electromagnet / coil.

[0305] The described system is envisioned for orienting a satellite or constellation of satellites relative to each other or other entities (i.e., attitude control), but can be used for altitude control or orbital assembly of larger structures from individually positionable components as well. Operation is not limited to space; the described system can have terrestrial applications, including, but not limited to, position control of drone vehicles. The system 10 and operating concepts described herein can also be applied to charged particle shielding, plasma manipulation, momentum exchange, and eddy current induction.

[0306] While the above describes some embodiments of the present invention with reference to satellites, the above may be equally applicable to any other suitable spacecraft that uses magnetic fields for position control, not necessarily satellites. In particular embodiments, the spacecraft and / or satellite may be those described in International Publication No. WO2020 / 174378A1 (PCT Application No. PCT / IB2020 / 051579), which is incorporated herein by reference in its entirety.

[0307] Where the foregoing description refers to elements or wholes that have known equivalents, such equivalents are included as if they were individually described.

[0308] It will, of course, be understood that the foregoing is set forth as illustrative examples of the present invention, but that all such modifications and variations that are apparent to those skilled in the art are deemed to be within the broad scope and ambit of the various aspects of the invention as defined above and / or in the claims.

Claims

1. 1. A system for generating a magnetic field in one or more axes, the system comprising: a primary electromagnet including a first coil having a first axis; a first secondary electromagnet including a second coil having a second axis; a second secondary electromagnet including a third coil having a third axis; the first, second, and third axes are non-parallel, and the first, second, and third coils are formed of superconductors; The system is a cooling element configured to cool the first, second, and third coils below a critical temperature of the superconductor; a power supply configured to provide power to the primary and secondary electromagnets. system.

2. The system of claim 1 , wherein one or more of the coils and / or the cooling element are insulated and / or thermally isolated from the surrounding environment.

3. The system of claim 1 , wherein two of the first, second, and third axes are orthogonal.

4. 3. The system of claims 1 and 2, wherein the first, second and third axes are orthogonal.

5. The system of claim 1 , wherein the first coil is a pancake coil.

6. The system of claim 1 , wherein the primary electromagnet further includes a frame member having an inner periphery and an outer periphery, and the first coil is wound around the outer periphery of the frame member.

7. The system of claim 6 , wherein the secondary electromagnet is attached to the frame member of the primary electromagnet.

8. 8. The system of claim 6 or 7, wherein the secondary electromagnet is mounted within the inner periphery of the frame member.

9. 5. A system according to any one of claims 1 to 4, wherein each of the secondary electromagnets is provided in the form of a solenoid.

10. The system of claim 1 , wherein the first, second, and third coils are wound on first, second, and third frame members, respectively.

11. The system of claim 10 , wherein the first, second, and third frame members are aligned and extend along the first axis.

12. 12. The system of claim 11, wherein the first, second, and third frame members are connected by a thermally conductive structural member, optionally the thermally conductive structural member being a cross rod.

13. 13. The system of claim 10, wherein the cooling element is at least partially disposed within an interior volume of the one or more frame members.

14. a third secondary electromagnet including a fourth coil having a fourth axis; a fourth secondary electromagnet including a fifth coil having a fifth axis; the fourth coil and the fifth coil are formed of a superconductor; 14. The system of claim 1, wherein the cooling element is further configured to cool the fourth coil and the fifth coil below the critical temperature of the superconductor.

15. 15. The system of claim 1, wherein the superconductor is a high temperature superconductor (HTS).

16. 16. The system of any one of claims 6 to 9 and claims 14 and 15, wherein the frame member is rectangular, each of the secondary electromagnets is mounted parallel to each side of the frame member, and the fourth and fifth axes are parallel to the second and third axes, respectively.

17. 17. A system according to any one of claims 6 to 9 and claims 14 to 16, wherein the frame member is supported by at least one bracket.

18. 20. The system of claim 17, wherein the frame member is suspended from the at least one bracket by an insulated structural member and / or an insulated spring.

19. 20. The system of claim 18, wherein the insulating structural member is a cable and / or the insulating structural member is formed from one of a metallic or non-metallic material including one or more of a polymer, a ceramic, a glass, Kevlar, a stainless steel, or a quartz.

20. 20. The system of claim 17, wherein the frame member is suspended by the insulating structural member from four brackets, one bracket positioned toward and supporting a respective corner of the frame member.

21. 21. The system of any one of claims 17 to 20, wherein the bracket includes an adjustable tensioning means for adjusting the tension of the insulating structural member.

22. 22. The system of claim 21, wherein the adjustable tensioning means includes a threaded spool around which the end of the insulating structural member is wound.

23. 23. The system of claim 21 or 22, wherein the adjustable tensioning means comprises one or more of a spring loaded pulley, a pinion, a roller, and a worm gear.

24. 24. The system of any one of claims 17 to 23, wherein the bracket includes an automatic tensioning means for maintaining tension in the insulating structural member.

25. 25. The system of any one of claims 17 to 24, wherein the bracket is formed from a resiliently flexible material and is configured to apply tension to the insulating structural member by virtue of its resiliency.

26. 26. A system according to claim 24 or 25, wherein the automatic tensioning means comprises a spring loaded pulley.

27. 27. The system of any one of claims 17-26, wherein the bracket is formed from a metallic or non-metallic material including one or more of a polymer, ceramic, glass, nylon, aluminum, titanium, a composite material, or PTFE.

28. 28. A system according to any preceding claim, wherein the cooling element comprises a thermal linkage in thermal contact with a heat extraction means.

29. 30. The system of claim 28, wherein the heat extraction means comprises one of a cryocooler, a heat pump, a heat exchanger, or a heat sink.

30. 30. The system of claim 29, wherein the cryocooler is one of a Stirling cryocooler, a pulse tube cryocooler, a pulse tube miniature cryocooler, a Gifford-McMahon cryocooler, a dilution refrigerator, an adiabatic demagnetization refrigerator, or a thermoelectric refrigerator.

31. 30. The system of claim 28, wherein the heat extraction means comprises a pair of cryocoolers arranged in opposing geometries to reduce net vibration during operation.

32. 30. The system of claim 28, wherein the heat extraction means includes a separate cryocooler for each of the primary and secondary electromagnets.

33. 33. The system of any one of claims 28 to 32, wherein the thermal linkage is disposed between the heat extraction means and the frame member and provides a thermal path between the heat extraction means and each coil of the primary and secondary electromagnets.

34. 34. The system of any one of claims 28 to 33, wherein the thermal linkage includes a flexible thermally conductive connector, the connector comprising one or more of braided copper, aluminum, or graphene.

35. 35. The system of claim 1, wherein the power source comprises an electromagnetic flux injection device.

36. 36. The system of claim 35, wherein the electromagnetic flux injector is an electromagnetic flux pump.

37. 37. The system of claim 36, wherein the electromagnetic flux pump is non-contact.

38. 38. The system of claim 36 or 37, wherein an electromagnetic flux pump is provided for each of the primary and secondary electromagnets.

39. 39. The system of any one of claims 1 to 38, further comprising a thermal insulating material arranged to reduce radiative heat transfer between the primary and secondary electromagnets and their surrounding environment.

40. 40. The system of claim 39, wherein the insulating material is a multi-layer insulating material.

41. 1. A system for generating a magnetic field in one or more axes, the system comprising: a primary electromagnet including a first coil having a first axis, the first coil being formed of a superconductor; a cooling element configured to cool the first coil below a critical temperature of the superconductor; a power supply configured to provide power to the primary electromagnet; the primary electromagnet includes a frame member; the frame member is suspended from at least one bracket by an insulating structural member and / or an insulating spring; system.

42. 42. The system of claim 41, wherein the first coil and the cooling element are insulated and / or thermally isolated from the surrounding environment.

43. 43. The system of claim 42, wherein the insulating structural member is a cable and / or the insulating structural member is formed from any metallic or non-metallic material including one or more of a polymer, ceramic, composite, glass, Kevlar, stainless steel, or quartz.

44. 44. The system of claim 42 or 43, wherein the frame member is rectangular and suspended by an insulated structural member from four brackets, one bracket positioned toward and supporting a respective corner of the frame member.

45. 45. The system of any one of claims 42 to 44, wherein the bracket includes an adjustable tensioning means for adjusting the tension of the insulating structural member.

46. 46. ​​The system of claim 45, wherein the adjustable tensioning means includes a threaded spool around which the end of the insulating structural member is wound.

47. 47. The system of claim 45 or 46, wherein the adjustable tensioning means comprises one or more of a spring loaded pulley, a pinion, a roller, and a worm gear.

48. 48. The system of any one of claims 42 to 47, wherein the bracket includes an automatic tensioning means for maintaining tension in the insulating structural member.

49. 49. The system of any one of claims 42 to 48, wherein the bracket is formed from a resiliently flexible material and is configured to apply tension to the insulating structural member by virtue of its resiliency.

50. 50. The system of any one of claims 48 and 49, wherein the automatic tensioning means includes a spring-loaded pulley.

51. 51. The system of any one of claims 42-50, wherein the bracket is formed of a metallic or non-metallic material including one or more of a polymer, ceramic, glass, nylon, aluminum, titanium, or PTFE.

52. a first secondary electromagnet attached to the frame member, the frame member including a second coil having a second axis, the second coil being formed of a superconductor; the first axis and the second axis are non-parallel; 52. The system of any one of claims 42-51, wherein the cooling element is further configured to cool the second coil below the critical temperature of the superconductor.

53. a second secondary electromagnet attached to the frame member, the frame member including a third coil having a third axis, the third coil being formed from a superconductor; the first, second, and third axes are non-parallel; 53. The system of claim 52, wherein the cooling element is further configured to cool the third coil below the critical temperature of the superconductor.

54. 54. The system of claim 53, wherein two of the first, second, and third axes are orthogonal.

55. 54. The system of claim 53, wherein the first, second, and third axes are orthogonal.

56. 56. The system of any one of claims 42 to 55, wherein the first coil is a pancake coil.

57. 56. The system of any one of claims 42 to 55, wherein the frame member has an inner periphery and an outer periphery, and the first coil is wound around the outer periphery of the frame member.

58. 58. The system of claim 57, wherein the secondary electromagnet is mounted within the inner periphery of the frame member.

59. 59. A system according to any one of claims 53 to 58, wherein each of the secondary electromagnets is provided in the form of a solenoid.

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