A mass driver

Abstract

Systems and method for configuring and operating a mass driver in the form of a quench launcher are provided. The launch tube includes a series of high-temperature semiconductor (HTS) coils arranged along its length and the launch vehicle includes an HTS coil. As the launch vehicle travels along the launch tube, it is pulled by each of the HTS coils arranged along the launch tube. Current and magnetic field regeneration is prevented using an arrangement of different types of switches, which includes cryogenic gap switch, a resistive gap switch, and a semiconductor switch.

Description

A MASS DRIVERCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. Provisional Application No. 63 / 524,255, filed June 30, 2023, the entire disclosure of which is herein expressly incorporated by reference.BACKGROUND OF THE INVENTION

[0002] Launching objects into space requires, among other things, achieving orbital velocity (e.g., 17,500+MPH for Earth orbit) to overcome the earth’s gravitational pull.. This is typically achieved by providing the launch vehicle with sufficient amount of fuel to achieve the necessary velocity to pass through the earth’s atmosphere into space. The fuel accordingly adds to the overall weight required to be accelerated to the necessary velocity. The weight of the added fuel increases at a rate greater than the proportional increase of the payload weight, thus greatly increasing costs and complexity.

[0003] Numerous approaches to launching objects into space relying primarily on external power sources to achieve orbital velocities have been considered but all have unresolved issues preventing a practical implementation. The simplest approach is a rail gun with a projectile (armature) arranged between two rails, one of which carries power to generate the Lorentz force to push the projectile forward. The Lorentz force is an inherently low efficiency method for converting electrical energy into kinetic energy or motion and requires contact between the rails and the projectile. Therefore, this also requires overcoming the corresponding heat, friction and wear between the rails and the projectile.

[0004] One of the more promising approaches is a high-temperature superconductor quench launcher, which is multi-coil solenoid launcher, an example of which is illustrated in Figures 1 A and 1 B. A series of high-temperature superconducting (HTS) coils 105 are arranged along the length of a launch tube 1 10 (containing a vacuum environment) and a launch vehicle 107, comprising a delivery cylinder 1 15 carrying a payload and, in some implementations a fuel source 120, arranged in a carrier sleeve 125 with one or more HTS coils 130. Energizing the HTS coils 105 and130 generates a magnetic field producing a levitating force (i.e., the Meissner effect) lifting and centering the carrier sleeve 125. Additional lifting and centering can also be achieved using magnets 135A and 135B respectively along the launch tube 1 10 and the carrier sleeve 125.

[0005] The HTS coils 105 along the launch tube 110 act as a stator and the HTS coil(s) 130 of the carrier sleeve 125 act as an armature. As the carrier sleeve 125 approaches one of the HTS coils 105, the magnetic field of the HTS coil 105 pulls the carrier sleeve 125 towards the HTS coil 105. As the carrier sleeve passes through the HTS coil 105 so that the carrier sleeve 125 is approximately centered with respect to the HTS coil 105 in the launch direction, the transfer of magnetic energy from the HTS coil 105 into the motion of the carrier sleeve 125 reduces the current in the HTS coil 105. The HTS coil 105 is only in this state for a very short period of time and the current will regenerate and disrupt (i.e., slow or stop) the movement of the carrier sleeve 125 along the launch tube 110 due to the newly regenerated magnetic field of the HTS coil 105 as a result of the regenerated current.

[0006] A solution to this issue, as well as other issues preventing a practical implementation of a quench launcher, have not yet been realized.SUMMARY OF THE INVENTION

[0007] Exemplary embodiments disclose solutions to a number of the unresolved problems preventing a practical implementation of a superconductor quench launcher. According to one aspect of the invention, an arrangement of different types of switches are provided for addressing problems arising when the HTS coils start to regenerate current. The arrangement includes a cryogenic gap switch, a resistive gap switch, and a semiconductor switch. Additionally, electromagnetic radiation can be applied to the HTS coils arranged along the launch tube to address current regeneration. In another aspect only electromagnetic radiation can be applied to the HTS coils arranged along the launch tube to address current regeneration without the arrangement of different types of switches. Another aspect involves coupling the backer of the HTS coils arranged along the launch tube to the arrangement of switches instead of directly coupling the conductor of the HTS coils to the arrangement of switches.

[0008] According to an aspect, there is a mass driver comprising a launch tube having a length; a series of high-temperature superconductor (HTS) coils arranged along the length of the launch tube; an arrangement of different types of switches electrically coupled to each HTS coil of the series of HTS coils, wherein the arrangement of different types of switches includes a cryogenic gap switch arranged in a cryogenic environment, and a resistive gap switch and a semiconductor switch arranged in ambient, wherein the cryogenic gap switch, the resistive gap switch, and the semiconductor switch are arranged in parallel with each other and in parallel with the respective HTS coil of the series of HTS coils.

[0009] The mass driver can further comprise a launch vehicle comprising an HTS coil, wherein an interaction of a magnetic field generated by the HTS coil of the launch vehicle and the series of HTS coils pulls the launch vehicle along the length of the launch tube to reach an acceleration that achieves a predetermined velocity for the launch vehicle. The mass driver can further comprise an electromagnetic energy source configured to produce electromagnetic energy to open the cryogenic gap switch. A switch controller can be provided that is configured to switch the resistive gap and semiconductor switches.

[0010] The mass driver can further comprise a stator power supply electrically coupled to each HTS coil of the series of HTS coils arranged along the length of the launch tube; and an armature power supply electrically coupled to the HTS coil of the launch vehicle, wherein the stator power supply and the armature power supply are configured so that the magnetic flux of the HTS coil of the launch vehicle causes the current in each HTS coil of the series of HTS coils to approach zero as the launch vehicle nears a middle of a respective HTS coil of the series of HTS coils.

[0011] The mass driver can alternatively comprise a plurality of stator power supplies electrically coupled to a respective one of the HTS coils of the series of HTS coils arranged along the length of the launch tube; and an armature power supply electrically coupled to the HTS coil of the launch vehicle, wherein the plurality of stator power supplies and the armature power supply are configured so that a magnetic flux of the HTS coil of the launch vehicle causes a current in each HTS coil of the series ofHTS coils to approach zero as the launch vehicle nears a middle of a respective HTS coil of the series of HTS coils.

[0012] The mass driver can comprise a stator power supply electrically coupled to each HTS coil of the series of HTS coils arranged along the length of the launch tube; and an armature power supply electrically coupled to the HTS coil of the launch vehicle, wherein the stator power supply and the armature power supply are configured so that a magnetic flux of the HTS coil of the launch vehicle causes a current in each HTS coil of the series of HTS coils to reverse as the launch vehicle nears a middle of a respective HTS coil of the series of HTS coils.

[0013] The mass driver can alternative comprise a plurality of stator power supplies electrically coupled to a respective one of the HTS coils of the series of HTS coils arranged along the length of the launch tube; and an armature power supply electrically coupled to the HTS coil of the launch vehicle, wherein the plurality of stator power supplies and the armature power supply are configured so that a magnetic flux of the HTS coil of the launch vehicle causes a current in each HTS coil of the series of HTS coils to reverse as the launch vehicle nears a middle of a respective HTS coil of the series of HTS coils.

[0014] One or more of the cryogenic gap switch, the resistive gap switch, and the semiconductor switch can be configured to switch between a closed circuit state and an open circuit state. Further, one or more of the cryogenic gap switch, the resistive gap switch, and the semiconductor switch is configured to switch between a closed circuit state and a state coupling a load to a dump resistor.

[0015] At least one of the cryogenic gap switch, the resistive gap switch, and the semiconductor switch are comprised of a plurality of switches arranged in parallel with each other, a plurality of switches arranged in series with each other, or a plurality of switches in which a first set of the plurality of switches are arranged in parallel with each other and a second set of the plurality of switches are arranged in series with each other or in series with the first set of plurality of switches.

[0016] According to a second aspect there is a mass driver comprising a launch tube having a length; a series of high-temperature superconductor (HTS) coils arranged along the length of the launch tube; an electromagnetic energy generator; and acontroller coupled to the electromagnetic energy generator and configured to control the electromagnetic energy generator to apply electromagnetic energy to each HTS coil of the series of HTS coils at predetermined times based on a distance between the HTS coil of the series of HTS coils and a launch vehicle configured to be launched via the quench launcher.

[0017] The electromagnetic energy generator can comprise a plurality of electromagnetic energy generators, each of which is configured to apply the electromagnetic energy to a respective on of the HTS coils. Each HTS coil of the series of HTS coils can comprise an HTS conductor with a non-electrically conductive backing layer. In an aspect, the non-conductive electrically backing layer can comprise glass. In an aspect, each HTS coil of the series of HTS coils does not need to include an electrically conductive backing layer.

[0018] According to a third aspect there a mass driver comprising a launch tube having a length; a series of high-temperature superconductor (HTS) coils arranged along the length of the launch tube, wherein each coil of the series of HTS coils comprises a coil of an HTS conductor having an electrically-conductive backing layer and a second HTS conductor coupled to a beginning and an end of the respective HTS coil; and an arrangement different types of switches electrically coupled to the electrically-conductive backing layer of each HTS coil of the series of HTS coils, wherein the arrangement of different types of switches includes a cryogenic gap switch arranged in a cryogenic environment, and a resistive gap switch and a semiconductor switch arranged in ambient, wherein the cryogenic gap switch, the resistive gap switch, and the semiconductor switch are arranged in parallel with each other and in parallel with the electrically-conductive backing layer of the respective HTS coil of the series of HTS coils.

[0019] At least one of the cryogenic gap switch, the resistive gap switch, and the semiconductor switch are comprised of a plurality of switches arranged in parallel with each other, a plurality of switches arranged in series with each other, or a plurality of switches in which a first set of the plurality of switches are arranged in parallel with each other and a second set of the plurality of switches are arranged in series with each other or in series with the first set of plurality of switches.

[0020] The mass driver can further comprise a launch vehicle comprising an HTS coil, wherein an interaction of a magnetic field generated by the HTS coil of the launch vehicle and the series of HTS coils pulls the launch vehicle along the length of the launch tube to reach an acceleration that achieves a predetermined velocity for the launch vehicle.

[0021] The mass driver can further comprise a stator power supply electrically coupled to each HTS coil of the series of HTS coils arranged along the length of the launch tube; and an armature power supply electrically coupled to the HTS coil of the launch vehicle, wherein the stator power supply and the armature power supply are configured so that magnetic flux of the HTS coil of the launch vehicle causes a current in each HTS coil of the series of HTS coils to approach zero or reverse as the launch vehicle nears a middle of a respective HTS coil of the series of HTS coils. Alternatively, the mass driver can further comprise a plurality of stator power supplies electrically coupled to a respective one of the HTS coils of the series of HTS coils arranged along the length of the launch tube; and an armature power supply electrically coupled to the HTS coil of the launch vehicle, wherein the plurality of stator power supplies and the armature power supply are configured so that a magnetic flux of the HTS coil of the launch vehicle causes a current in each HTS coil of the series of HTS coils to approach zero or reverse as the launch vehicle nears a middle of a respective HTS coil of the series of HTS coils.BRIEF DESCRIPTION OF DRAWINGS

[0022] Figures 1 A and 1 B are illustrations of conventional quench launcher components;

[0023] Figures 2A and 2B are schematic diagrams of a mass driver in the form of a quench launcher according to exemplary embodiments of the invention;

[0024] Figure 3 is a schematic diagram of a high-temperature semiconductor (HTS) coil in a launch tube according to exemplary embodiments of the invention;

[0025] Figure 4 is a flow chart of a method for quench launching according to exemplary embodiments of the invention;

[0026] Figure 5 is a schematic diagram of an HTS coil in a launch tube according to exemplary embodiments of the invention;

[0027] Figure 6A schematically illustrates a cross-section of a conventional HTS coil arrangement;

[0028] Figure 6B schematically illustrates a cross-section of an HTS coil arrangement according to exemplary embodiments; and

[0029] Figure 7 is a schematic diagram of a high-temperature semiconductor (HTS) coil in a launch tube according to exemplary embodiments of the invention.DETAILED DESCRIPTION OF THE INVENTION

[0030] In the following description like reference numbers are used to designate similar parts / components. As discussed above, in a quench launcher the HTS coils of the launch vehicle are powered to generate a magnetic field so that it operates as an armature, and accordingly references herein to an armature should be understood as referring the launch vehicle. Similarly, the series of HTS coils arranged along the launch tube (containing a vacuum environment) are powered to generate a magnetic field so that it operates as a stator, and accordingly references herein to a stator should be understood as referring each of the HTS coils arranged along the launch tube.

[0031] Figure 2A illustrates a mass driver in the form of a quench launcher 200A, including a launch tube 210 and a launch vehicle 207 arranged in an initial launch position outside and behind the launch tube 210. The launch vehicle includes a carrier sleeve 225 with an HTS coil 230 electrically or inductively coupled to armature power supply 255, which provides direct current (DC) current to the HTS coil 230 so that it generates the necessary magnetic field for quench launching. Similarly, the launch tube 210 includes a series of HTS coils 205i-205x electrically coupled to a stator power supply 265, which provides DC current to the series of HTS coils 205i-205x to generate the necessary magnetic fields for the launch vehicle to be accelerated to a predetermined velocity (e.g., orbital velocity). This acceleration is achieved by the respective arrangement of different types of switches 270i-270x, which prevent the respective HTS coil 205i-205x from regenerating a magnetic field having sufficient strength to affect the acceleration of the launch vehicle 207 as it passes along the launch tube 210. As illustrated, a switch controller 275 controls the arrangements of the different types of switches 270, the switch controller can be embodied as a computer, server, application-specific integrated circuit, and / or the like that is programmed tocontrol the arrangement of different types of switches 270 in the manner disclosed herein.

[0032] Details of the arrangement of the different types of switches 270, as well as the overall operation of the launch sequence will now be described in more detail in connection with Figures 3 and 4, as well as continued reference to Figure 2A.

[0033] Referring to Figure 3, the arrangement of the different types of switches 270 includes a first switch S1 arranged in the cryogenic environment 302 connected in parallel with second S2 and third S3 switches arranged in the ambient environment 301 . The first switch S1 is a cryogenic gap switch, which is high conductivity metal switch in the cryogenic environment 302 that minimizes current losses after charging the HTS coil 205 and prior to launch. As will be appreciated from the discussion herein, the most important property of the cryogenic gap switch S1 is high conductivity and switching speed is less of a concern due to the use of the second S2 and third S3 switches. The second switch S2 is a gap switch in the ambient environment 301 , and the third switch S3 is semiconductor switch in the ambient environment 301 . Switches S1 -S3 can each consist of a single switch or multiple components / switches that are arranged in series and / or parallel. Thus, references to a first, second, and / or third switch should be understood as the referenced switch as including a single switch or an arrangement of the same types of switches. For example, the first (cryogenic gap) switch S1 can comprise an arrangement of cryogenic switches arranged in parallel and / or in series with each other. Similarly, the second (gap) switch S2 can comprise an arrangement of mechanical switches arranged in parallel and / or in series with each other. Further, the third (semiconductor) switch S3 can comprise an arrangement of semiconductor switches arranged in parallel and / or in series with each other. For ease of illustration, and not limitation, the three types of switches S1 -S3 are illustrated as switching between a closed state and an open state. One of more of the three types of switches S1 -S3, however, can switch between a closed state and a second state where the switch connects the HTS coil 205 to a load (sometimes referred to as a dump load). As also illustrated in Figure 3, a power supply protection switch S4 is arranged in parallel with the stator power supply 265, as is conventional in the art.

[0034] Referring now to Figures 2A, 3, and 4, in the pre-launch phase, the HTS coil 230 of the launch vehicle 207 is powered by armature power supply 255 and the HTS coils 205i-205x of the launch tube 210 are powered by the stator power supply 265 to generate the necessary magnetic fields for launch (step 405). Armature power supply 255 and stator power supply 265 are then disconnected from HTS coil 230 of the launch vehicle 207 and the HTS coils 205i-205x of the launch tube 210 (step 410). The HTS coil 230 of the launch vehicle 207 and the HTS coils 205i-205x of the launch tube 210 should be powered to achieve respective currents that generate the necessary magnetic fields for the HTS coils 205i-205x of the launch tube 210 to pull the launch vehicle 207 along the launch tube 210 and achieve a predetermined velocity (e.g., orbital velocity). Further, the current in the HTS coil 230 of the launch vehicle 207 should also be selected so that as the HTS coil 230 of the launch vehicle 207 nears the middle of one of the HTS coils 205i-205x of the launch tube, the magnetic field generated by the HTS coil 230 of the launch vehicle 207 causes the current in the particular one of the HTS coils 205i-205x of the launch tube to zero or near zero, or alternatively to drive the current in the particular one of the HTS coils 205i-205x of the launch tube so that the current reverses, which further hinders regeneration of the magnetic field for the particular one of the HTS coils 205i-205x. It will be recognized that the magnitude of the reversed current should be relatively small. With knowledge of the disclosure herein, the person of ordinary skill in the art could readily calculate such currents. Driving the current in the HTS coils to zero, near zero, or reverse is known as kick quenching, in which the HTS coil suffers multiple orders of reduction in their conductivity, and the change from superconducting to the significantly reduced conductivity is dramatic. Kick quenching can also be achieved by heating the HTS coils (which must be maintained below a certain temperature to maintain their superconductivity), applying a large amount of current, and applying electromagnetic energy (e.g., radio frequency energy) to the HTS coils.

[0035] Because coils 205i-205xand 230 are superconductors, the coils will maintain the current any, minimal losses, being largely attributable to the cryogenic gap switch S1 . The disconnection of the armature power supply 255 can be achieved with an armature shorter 260, which creates a short-circuit in the HTS coil 230 of the launchvehicle 207 so that the current is maintained in the HTS coil 230. Disconnection of the stator power supply 265 from the HTS coils 205i-205x can be achieved, for example, using retractable leads 309, which is illustrated in Figures 3A and 3B, and is how magnetic resonance imaging (MRI) machines are typically powered.

[0036] The quench launcher is now in the firing state, and accordingly the first switch S1 of the first HTS coil 205i of the launch tube is opened (step 415).Specifically, an electromagnetic energy source 385 produces electromagnetic energy 390 that causes the first (cryogenic gap) switch S1 to open. The electromagnetic energy source 385 can be controlled by switch controller 275 or by a separate controller (not illustrated), either of which can be a computer, server, application-specific integrated circuit, and / or the like that is programmed to control the electromagnetic energy source 385 in the manner disclosed herein. The first switch S1 of the first HTS coil 205i can be opened several seconds or a fraction of a second prior to firing time. Once the first switch S1 of the first HTS coil 205i is opened and the current in the coil is transferred to the second (gap) switch S2.

[0037] The launch vehicle 207 is then moved from the initial launch position into the firing position so that the magnetic field of the launch vehicle 207 is pulled by the magnetic field of the first HTS coil 205i of the launch tube 210 (step 420). This can be achieved a number of different ways, such as by arranging a solid fuel rocket motor at the rear end of the launch vehicle, as discussed in the Background section above, which could also be used with the embodiments disclosed herein. Figure 2A illustrates an alternative in which a launch vehicle lock 250, which holds the launch vehicle in placed regardless of whether the HTS coil 230 of the launch vehicle 207 and / or the HTS coils 205 of the launch tube 210 are generating magnetic fields. This can be achieved, for example, by generating a sufficient magnetic force, from example from behind, to hold the launch vehicle 207 in place, by a mechanical structure holding the launch vehicle 207 in place, and / or any other similar arrangement.

[0038] As the launch vehicle 207 ends and nears the mid-point of the first HTS coil 205i the switch controller 275 opens the second (gap) switch (step 425), which transfers the current to the third (semiconductor) switch, which is then opened (step 430). As the launch vehicle 207 is centered along the axial length of the first HTS coil205i, the interaction of the magnetic fields of the HTS coils 230 of the launch vehicle 207 and the first HTS coil 205i of the launch tube interact, which transfers energy from the magnetic flux of the first HTS coil 205i into kinetic motion of the launch vehicle 207, which then drives the current in the first HTS coil 205i to zero (or near zero). Due to the arrangement of different types of switches 270 the current (and accordingly the associated magnetic field) is not regenerated in the first HTS coil 205i, thus allowing the launch vehicle 207 to freely move away from the first HTS coil 205i as it is pulled by the magnetic field of the second the HTS coil 2052. Steps 415-430 are then repeated by the second HTS coil 2052 and each subsequent HTS coil 205s-205x until the launch vehicle 207 exits the launch tube 210 with sufficient acceleration to reach orbital velocity. The costs of such a system can be reduced by employing a reusable carrier sleeve 225, such that the payload of the launch vehicle 207 is launched out of the launch tube 210 without the carrier sleeve so that the carrier sleeve can be reused for launching another payload.

[0039] The disclosed arrangement of different types of switches addresses the current regeneration problem that has prevented practical implementation of a quench launcher. A cryogenic gap switch typically has a switch interval of ~ 100 ms, whereas preventing current regeneration requires causing the HTS coil 205 to cease conduction on the order of ~100 ns. Thus, a cryogenic gap switch alone may not be able to cease current regeneration quick enough to allow the launch vehicle 207 to continue without being pulled back by the HTS coil. The third (semiconductor) switch S3 has a significantly shorter switch interval (e.g., silicon carbide MOSFETS have switching interval in the range of tens of nanoseconds) than the first (cryogenic gap) HTS switch S1 and accordingly switches quickly enough to prevent the undesirable current regeneration. However, the third (semiconductor) switch S3 will have a large forward voltage drop, and thus the second (gap) switch S2 reduces the amount of energy wasted as heat in the switches because the second (gap) switch S2 will have a voltage drop at least two orders of magnitude less than the third (semiconductor) switch S3. Accordingly, the parallel arrangement of switches act quickly enough to prevent current regeneration, while also preventing destruction of one or more of the switches due to the high voltages that can occur during this process.

[0040] For ease of explanation, and not limitation, the disclosed method is described with opening all of the switches of the arrangement of different types of switches 270 of one HTS coil 205 and then opening all of the switches of the arrangement of different types of switches 270 of next HTS coil 205 along the launch tube 210. However, due to the high speeds involved, individual switches of a subsequent HTS coil 205 can be opened prior to opening all of the individual switches of a prior HTS coil 205. For example, the first (cryogenic gap) switch S1 of the second HTS coil 2052 can be opened prior to opening the second (gap) switch S2 and third (semiconductor) switch S3 of the first HTS coil 205i.

[0041] As an alternative to employing a common power supply 265 for all of the HTS coils 205 of the vacuum tube, which is illustrated in Figure 2B, separate power supplies 265i-265x coupled to respective ones of the HTS coils 205i-205x. The quench launcher can alternatively be configured with a multiple power supplies, each powering two or more of the HTS coils 205i-205x (not illustrated). Further, in the alternative illustrated in Figure 2B, a separate switch controller 275i-275x is arranged to control a respective one of the arrangements of the plurality of switches 270i-270x. Otherwise, the quench launcher 200B illustrated in Figure 2B is identical to the quench launcher 200A illustrated in Figure 2A. It should be recognized that the configurations in Figures 2A and 2B can be combined so that there is a common switch controller 275 for all arrangements of the plurality of switches 270i-270x but separate power supplies 265i- 265x coupled to respective ones of the HTS coils 205i-205x, or separate switch controllers 275i-275x but a common power supply 270.

[0042] Figure 5 is a schematic diagram of another configuration of the HTS coils 205 arranged along the launch tube. This arrangement does not include the arrangement of different types of switches. Instead, regeneration of the current and magnetic field are achieved solely by applying electromagnetic waves to the HTS coil 205, which quenches the coil and therefore changes (i.e., switches) the coil from being an essentially perfect conductor to a poor conductor. . In order to prevent a potential quench path through the electrically-conductive backing of the HTS coils 205, the structure of the HTS coils 205 can be modified to use a non-conductive backer. Specifically, Figure 6A illustrates a conventional HTS coil arrangement with an HTS603A and affixed to an electrically-conductive backer 604B, such as a layered structure including Hastelloy steel (a nickel metal alloyed to increase corrosion resistance, such as through the addition of molybdenum and chromium) and silver. The backer 603B is designed to be electrically-conductive so that any quenching can be discharged through the backer 603B (otherwise a quench event can have catastrophic consequences). Thus, while HTS coils are conventionally designed with an electrically-conductive backer 603B, in the embodiment of Figure 5 such a quench path is not desired. Accordingly, as illustrated in Figure 6B, the HTS coil arrangement can include an HTS coil 603A with a non-electrically-conductive backer 603C, such as glass, e.g., glass sold by Corning under the tradename Gorilla Glass. Accordingly, in the arrangement of Figure 5 the HTS coil arrangement 205 includes an HTS coil with a non-electrically- conductive backer.

[0043] Another alternative for preventing current and magnetic field regeneration will be described in connection with the schematic diagram illustrated in Figure 7. This configuration is similar to the configuration described above in connection with Figure 3 and like reference numbers refer to similar components. Compared to the configuration of Figure 3, in the configuration of Figure 7 the HTS coil arrangement 705 includes an HTS conductor with an electrically-conductive backer 705i arranged as a coil and an HTS conductor 7052 without an electrically-conductive backer is connected between the ends of the HTS coil formed by the HTS conductor with an electrically-conductive backer 705i. Further, in the configuration of Figure 3 the arrangement of switches S1 - S3 are coupled to the HTS conductor of the HTS coil 205, whereas in Figure 7 the metal backer of the HTS 705i is coupled to the arrangement of switches S1 -S3. The activation of the switches S1 -S3 operate in a similar manner to that described above in connection with Figures 3 and 4 except that the switches are in an electrical path of the electrically-conductive backer of the HTS coil 705i. Any regenerated current will occur in the electrically-conductive backer of the HTS coil 705i, which will be largely prevented by the arrangement of switches S1 -S3 being switched in the manner described above.

[0044] An implementation of a quench launcher is now discussed with specific values. These values should be understood as examples, and not as the only valuesthat can be employed. The kinetic energy KE of the launch vehicle 207 can be calculated as:where q is the magnetic-to-kinetic energy conversion efficiency, B is the magnetic flux density, D is the stator winding diameter, po is the permeability of free space, and I is the length of the acceleration magnetics. Assuming, for example, a 50,900 kg mass of the launch vehicle 207, and a desired 5.6 km / s muzzle velocity at the exit of the launch tube 210, the kinetic energy at muzzle exit would be 7.98 x1011Joules (or roughly 0.8 Terajoules / 800 Gigajoules).

[0045] Assuming, for example, a launcher length (I) of 15 km, and a diameter of the HTS coil 205 (i.e., stator coil) of 1 .2 m, the minimum necessary B field requirement is 10.87 Tesla. If the conversion efficiency is not the assumed 100%, but is instead 50%, the B field requirement increases to 15.38 Tesla.

[0046] The B field (flux density) of a solenoid is expressed as:B = ionl [2] where n is the turns per unit length (turns per meter), and I the current. The permeability of free space is used for these calculations because at the B field strengths under consideration, even ferromagnetic materials would not add substantially to the field as they will saturate above ~2 T, and because the vast majority of the bore is occupied by a vacuum or a composite (S-glass / epoxy) bore liner.

[0047] Selecting, for example, the turns-per-meter to be 80 (or 1 .25 cm winding center-to-center distance), the current required is 108 kA and 153 kA for 10.87 and 15.38 Tesla, respectively. A winding density of 80 turns per meter is about as high as one can go in a single layer and still meet current density limitations (0.2 MA / cm2) in standard YBCO (yttrium barium copper oxide) HTS and still leave enough room for insulation.

[0048] The inductance L of the solenoid stator coil 205 is: n / j.0N2D2L =41 [3] where L is the inductance (in Henries), N is the number of turns, and I is the stator length.

[0049] The inductance L of the solenoid stator coil 205 can also be represented by:where n is the winding density, rather than number of turns. Assuming, for example, a length of the HTS coil 205 in the launch tube of 0.2 meters, the inductance is 1 .82 millihenries (or 1 .82E-3 Henries).

[0050] The total flux (<t>), in Webers, stored in the HTS coil 205 is:<P = LI

[0051] Thus, the total flux is 196 Webers and 278 Webers, at 10.8 and 15.3 Tesla, respectively.

[0052] To determine the maximum reverse voltage standoff requirement for the arrangement of different types of switches 270, first consider the rate at which the launch vehicle 207 is moving relative to the HTS coil 205. Based on Faraday’s Law:where t is time. The stator-armature interaction can be approximated as a general heuristic to assume full flux collapse by the time the launch vehicle 207 has moved 1 stator diameter (i.e., the diameter of the HTS coil 205) from longitudinal center. Thus, at 5.6 km / s and 1 .2 meter diameter, dt is approximately 214 microseconds (2.14E-4 seconds). Using this heuristic, the maximum switch standoff voltage is 917kV and 1 .3 MV, for 10.8 and 15.3 Tesla, respectively.

[0053] To summarize, the requirements for a launch tube 210 having a 1 .2 m diameter and a 15 km length:

[0054] Increasing the diameter relaxes the B field requirement. Thus, at 2 meters diameter (and 0.2 m length), the requirements become:

[0055] Thus, only the current rating becomes relaxed by increasing diameter (and thus decreasing required B field).

[0056] Assuming, for example, that the third (semiconductor) switch S3 is an Infineon D3001 N rectifier diode, the required series-parallel array dimension required in each of the previous cases is now determined. Vtorward and associated conduction losses during the 0.5 milliseconds that the third (semiconductor) switch S3 is the sole stator current path prior to the arrival of the launch vehicle 107:

[0057] The second (gap) switch S2, which is a resistive switch, must also standoff the same reverse voltage as it is in parallel and it must be able to move from a closed to an open state in 0.5 ms. The voltages involved are in range of high hundreds of kV to megavolts, and therefore the standoff distance for a switch gap would have to be quite large (>137 mm in one instance), even if immersed in a dielectric fluid with breakdown field strength of ~16 MV / m.

[0058] To simplify the design of the second (gap) switch S2 it is possible to break it up into segments, such that the standoff voltage per segment is more reasonable (on the order of 100 kV). One drawback of this simplification is that each additional segment adds contact resistance, which is significantly higher than the resistance of the bulk material. Keeping the number of segments s to be 10 or less, this contact resistance (approximately 70 pohm / cm2for each contact) should be acceptable, given a maximum switch design current density of 4000A / cm2.

[0059] Because the segmented second (gap) switch S2 is operated inside of a reservoir of a dielectric oil (transformer oil), the effect in terms of the stroke of the contactor, and the required average velocity and acceleration (given 0.5 msec actuation time) are given in the following table:

[0060] As will be appreciated by the discussion above, the velocity specifications for the operation of the segmented second (gap) switch S2 are on par with velocities seen in many industrial and automotive mechanisms and are thus quite feasible. The required initial acceleration of the launch vehicle 207 can be achieved by a powerful actuation mechanism, for example a gas actuator for the necessary first velocity to move into the first stator. Deceleration of the reusable carrier sleeve 225 can be achieved using regenerative braking, eddy current braking, and in the last meters of distance and at lower speeds with a “soft catch” of the carrier sleeve 225 by air brakes or other methods.

[0061] Although exemplary embodiments have been discussed referring to a quench launcher, it should be recognized that the disclosed systems and methods can be more generically referred to as a mass driver. Further, the disclosed systems and methods can also be used in applications other than launching mass, such as any application requiring inducing large accelerations into a mass to drive the mass over a distance.

[0062] For ease of explanation, and not limitation, the discussion above involved launching objects from earth. The disclosed embodiments can also be used for launching objects from other astronomical objects, such as asteroids, , moons, and the like. Although launching from these astronomical objects may not require the same amount of velocity as from earth, due to lower gravitational and atmospheric forces, the disclosed embodiments can achieve high rates of velocity, reducing the amount of time to reach the intended destination. It should be recognized that for astronomical objects without an atmosphere, or a very thin atmosphere, the vacuum tube is unnecessary.

[0063] Although the invention has been illustrated and described in detail by way of preferred embodiments, the invention is not limited by the examples disclosed, and other variations can be derived from these by the person skilled in the art without leaving the scope of the invention. It is therefore clear that there is a plurality of possible variations. It is also clear that embodiments stated by way of example are only really examples that are not to be seen as limiting the scope, application possibilities or configuration of the invention in any way. In fact, the preceding description and the description of the figures enable the person skilled in the art to implement the exemplaryembodiments in concrete manner, wherein, with the knowledge of the disclosed inventive concept, the person skilled in the art is able to undertake various changes, for example, with regard to the functioning or arrangement of individual elements stated in an exemplary embodiment without leaving the scope of the invention, which is defined by the claims and their legal equivalents, such as further explanations in the description.

Claims

WHAT IS CLAIMED IS:1 . A mass driver comprising: a launch tube having a length; a series of high-temperature superconductor (HTS) coils arranged along the length of the launch tube; and an arrangement of different types of switches electrically coupled to each HTS coil of the series of HTS coils, wherein the arrangement of different types of switches includes a cryogenic gap switch arranged in a cryogenic environment, and a resistive gap switch and a semiconductor switch arranged in ambient, wherein the cryogenic gap switch, the resistive gap switch, and the semiconductor switch are arranged in parallel with each other and in parallel with the respective HTS coil of the series of HTS coils.

2. The mass driver of claim 1 , further comprising: a launch vehicle comprising an HTS coil, wherein an interaction of a magnetic field generated by the HTS coil of the launch vehicle and the series of HTS coils pulls the launch vehicle along the length of the launch tube to reach an acceleration that achieves a predetermined velocity for the launch vehicle.

3. The mass driver of claim 1 , further comprising: an electromagnetic energy source configured to produce electromagnetic energy to open the cryogenic gap switch.

4. The mass driver of claim 3, further comprising: a switch controller configured to switch the resistive gap switch and the semiconductor switch.

5. The mass driver of claim 2, further comprising: a stator power supply electrically coupled to each HTS coil of the series of HTS coils arranged along the length of the launch tube; and an armature power supply electrically coupled to the HTS coil of the launch vehicle,wherein the stator power supply and the armature power supply are configured so that a magnetic flux of the HTS coil of the launch vehicle causes a current in each HTS coil in the series of HTS coils to approach zero as the launch vehicle nears a middle of a respective HTS coil of the series of HTS coils.

6. The mass driver of claim 2, further comprising: a plurality of stator power supplies electrically coupled to a respective one of the HTS coils of the series of HTS coils arranged along the length of the launch tube; and an armature power supply electrically coupled to the HTS coil of the launch vehicle, wherein the plurality of stator power supplies and the armature power supply are configured so that a magnetic flux the HTS coil of the launch vehicle causes a current in each HTS coil of the series of HTS coils to approach zero as the launch vehicle nears a middle of a respective HTS coil of the series of HTS coils.

7. The mass driver of claim 2, further comprising: a stator power supply electrically coupled to each HTS coil of the series of HTS coils arranged along the length of the launch tube; and an armature power supply electrically coupled to the HTS coil of the launch vehicle, wherein the stator power supply and the armature power supply are configured so that a magnetic flux of the HTS coil of the launch vehicle causes a current in each HTS coil of the series of HTS coils to reverse as the launch vehicle nears a middle of a respective HTS coil of the series of HTS coils.

8. The mass driver of claim 2, further comprising: a plurality of stator power supplies electrically coupled to a respective one of the HTS coils of the series of HTS coils arranged along the length of the launch tube; and an armature power supply electrically coupled to the HTS coil of the launch vehicle,wherein the plurality of stator power supplies and the armature power supply are configured so that a magnetic flux of the HTS coil of the launch vehicle causes a current in each HTS coil of the series of HTS coils to reverse as the launch vehicle nears a middle of a respective HTS coil of the series of HTS coils.

9. The mass driver of claim 1 , wherein one or more of the cryogenic gap switch, the resistive gap switch, and the semiconductor switch is configured to switch between a closed circuit state and an open circuit state.

10. The mass driver of claim 1 , wherein one or more of the cryogenic gap, resistive gap, and semiconductor switches is configured to switch between a closed circuit state and a state coupling a load to a dump resistor.1 1 . The mass driver of claim 1 , wherein at least one of the cryogenic gap switch, the resistive gap switch, and the semiconductor switch are comprised of a plurality of switches arranged in parallel with each other, a plurality of switches arranged in series with each other, or a plurality of switches in which a first set of the plurality of switches are arranged in parallel with each other and a second set of the plurality of switches are arranged in series with each other or in series with the first set of plurality of switches.

12. A mass driver comprising: a launch tube having a length; a series of high-temperature superconductor (HTS) coils arranged along the length of the launch tube; an electromagnetic energy generator; and a controller coupled to the electromagnetic energy generator and configured to control the electromagnetic energy generator to apply electromagnetic energy to each HTS coil of the series of HTS coils at predetermined times based on a distance between the HTS coil of the series of HTS coils and a launch vehicle configured to be launched via the mass driver.

13. The mass driver of claim 12, wherein the electromagnetic energy generator comprises a plurality of electromagnetic energy generators, each of which is configured to apply the electromagnetic energy to a respective on of the HTS coils.

14. The mass driver of claim 12, wherein each HTS coil of the series of HTS coils comprises an HTS conductor with a non-electrically conductive backing layer.

15. The mass driver of claim 14, wherein the non-electrically conductive backing layer comprises glass.

16. The mass driver of claim 12, wherein the each HTS coil of the series of HTS coils does not include an electrically conductive backing layer.

17. A mass driver comprising: a launch tube having a length; a series of high-temperature superconductor (HTS) coils arranged along the length of the launch tube, wherein each coil of the series of HTS coils comprises a coil of an HTS conductor having an electrically-conductive backing layer and a second HTS conductor coupled to a beginning and an end of the respective HTS coil; and an arrangement different types of switches electrically coupled to the electrically- conductive backing layer of each HTS coil of the series of HTS coils, wherein the arrangement of different types of switches includes a cryogenic gap switch arranged in a cryogenic environment, and a resistive gap switch and a semiconductor switch arranged in ambient, wherein the cryogenic gap, resistive gap, and semiconductor switches are arranged in parallel with each other and in parallel with the electrically- conductive backing layer of the respective HTS coil of the series of HTS coils.

18. The mass driver of claim 17, wherein at least one of the cryogenic gap switch, the resistive gap switch, and the semiconductor switch are comprised of a plurality of switches arranged in parallel with each other,a plurality of switches arranged in series with each other, or a plurality of switches in which a first set of the plurality of switches are arranged in parallel with each other and a second set of the plurality of switches are arranged in series with each other or in series with the first set of plurality of switches.

19. The mass driver of claim 17, further comprising : a launch vehicle comprising an HTS coil, wherein an interaction of a magnetic field generated by the HTS coil of the launch vehicle and the series of HTS coils pulls the launch vehicle along the length of the launch tube to reach an acceleration that achieves a predetermined velocity for the launch vehicle.

20. The mass driver of claim 19, further comprising : a stator power supply electrically coupled to each HTS coil of the series of HTS coils arranged along the length of the launch tube; and an armature power supply electrically coupled to the HTS coil of the launch vehicle, wherein the stator power supply and the armature power supply are configured so that a magnetic flux of the HTS coil of the launch vehicle causes a current in each HTS coil of the series of HTS coils to approach zero or reverse as the launch vehicle nears a middle of a respective HTS coil of the series of HTS coils.21 . The mass driver of claim 19, further comprising : a plurality of stator power supplies electrically coupled to a respective one of the HTS coils of the series of HTS coils arranged along the length of the launch tube; and an armature power supply electrically coupled to the HTS coil of the launch vehicle, wherein the plurality of stator power supplies and the armature power supply are configured so that a magnetic flux of the HTS coil of the launch vehicle causes current in each HTS coil of the series of HTS coils to approach zero or reverse as the launch vehicle nears a middle of a respective HTS coil of the series of HTS coils.

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