SINGLE-STAGE CRAFT AND METHOD FOR INTERPLANETARY SPACE TRAVEL

Abstract

An interplanetary spacecraft makes use of ambient cosmic rays and muons generated therefrom to provide micro-fusion propulsion. The craft has a central reaction chamber surrounded by the craft's main body. Deuterium-containing fuel material is injected at a specified rate into the reaction chamber where it is exposed to the cosmic rays and muons to produce energetic reaction products. Some reaction products exit the chamber through an opening to provide reaction thrust, while other reaction products interact with a dome of the chamber to directly apply a thrusting force. The craft can be a preassembled station having multiple reaction chambers and can form an orbiting space station around a planet or moon or a manufacturing or habitat station on a planetary or lunar surface.

Claims

1. A method of interplanetary space travel using a single-stage craft propelled in the presence of ambient cosmic rays, the method comprising: providing a spacecraft having a central reaction volume with at least an upper cover and a bottom opening and also having a main body surrounding the reaction volume, the main body having a supply of deuterium-containing micro-fusion particle fuel material; dispersing a quantity of the fuel material into the reaction volume at a specified rate through one or more ports in side walls of the reaction volume, the fuel material interacting with an ambient flux of cosmic rays entering the reaction volume through the upper cover and with muons generated from the cosmic rays to produce reaction products having kinetic energy; and allowing a downwardly directed portion of the reaction products to exit the reaction volume through the bottom opening to produce reaction thrust and stopping an upwardly directed portion of the reaction products by the upper cover to produce upward applied thrust upon the craft.

2. The method as in claim 1, wherein the upper cover is a double-paned dome with muon generating material therebetween, collisions of cosmic rays with the muon generating material supplying muons to the deuterium-containing particle fuel material to facilitate generation of energetic reaction products.

3. The method as in claim 1, wherein the bottom opening of the reaction volume includes a deflection mechanism for selectively deflecting electrically charged reaction products escaping through the bottom opening to produce a specified direction of lateral motion.

4. The method as in claim 1, wherein the side walls of the reaction volume contain a set of radial output ports that selectively permit some energetic reaction products to escape in a specified lateral direction.

5. The method as in claim 4, wherein radial output ports are selected using a moveable partial ring that covers all but a small number of selected radial output ports.

6. The method as in claim 4, wherein radial output ports are selected by opening and closing specified valves on such ports.

7. The method as in claim 1, wherein the reaction volume has a size selected such that thrust obtained exceeds gravitational force for a steady ground-based launch of the craft into orbit.

8. The method as in claim 1, wherein the craft further comprises a supplemental supply of deuterium-containing micro-fusion fuel particles coupled proximate to a bottom opening of the reaction volume, such that supplemental deuterium-containing fuel particles can be propelled externally below an underside of the craft so as to interact with ambient cosmic rays and muons external to the craft to produce reaction products having kinetic energy, an upwardly directed portion of the reaction products applying additional upward thrust upon the underside of the craft.

9. The method as in claim 1, wherein a craft accelerates into successively higher orbits around a planet or moon of origination prior to insertion into an interplanetary trajectory.

10. The method as in claim 1, wherein a craft decelerates into successively lower orbits around a destination planet or moon prior to entry into a landing trajectory.

11. The method as in claim 1, wherein the craft travels round-trip between source and destination planets.

12. A single-stage interplanetary space craft operable in the presence of ambient cosmic rays, comprising: a central reaction volume with at least an upper cover and a bottom opening; a main body surrounding the reaction volume, the main body having a supply of deuterium-containing micro-fusion fuel particles for injection into the central reaction volume via a set of one or more ports in side walls of the reaction volume; wherein the fuel material, when dispersed within the central reaction volume, interacts with an ambient flux of cosmic rays entering the reaction volume through the upper cover and with muons generated from the cosmic rays to produce reaction products having kinetic energy, a downwardly directed portion of the reaction products exiting the reaction volume through the bottom opening to produce reaction thrust and an upwardly directed portion of the reaction products being stopped by the upper cover to produce upward applied thrust upon the craft.

13. The craft as in claim 12, wherein the side walls of the reaction volume contain a set of radial output ports that selectively permit some energetic reaction products to escape in a specified lateral direction.

14. The craft as in claim 13, wherein a moveable partial ring covers all but a small number of selected radial output ports.

15. The craft as in claim 13, wherein each radial output ports includes a corresponding selectively openable and closeable valve.

16. The craft as in claim 12, wherein the upper cover is a dome permitting cosmic rays and muons to penetrate while also blocking energetic reaction products generated within the reaction volume.

17. The craft as in claim 12, wherein the central reaction volume has a size selected such that thrust obtained exceeds gravitational force.

18. The craft as in claim 12, further comprising a supplemental supply of deuterium-containing micro-fusion fuel particles coupled proximate to a bottom opening of the reaction volume, such that supplemental deuterium-containing fuel particles can be propelled externally below an underside of the craft so as to interact with ambient cosmic rays and muons external to the craft to produce reaction products having kinetic energy, an upwardly directed portion of the reaction products applying additional upward thrust upon the underside of the craft.

19. The craft as in claim 12, comprising a preassembled space station having at least one reaction volume to put the space station into orbit around a planet or moon and to maintain that orbit.

20. The craft as in claim 19, wherein the space station has two or more reaction volumes, each reaction volume coupled to a supply of deuterium-containing micro-fusion fuel particles, each reaction volume having at least an upper cover and a bottom opening.

21. The craft as in claim 12, comprising a preassembled manufacturing station having at least one reaction volume to transport the manufacturing station to a surface of a planet or moon.

22. The craft as in claim 21, wherein the manufacturing station has two or more reaction volumes, each reaction volume coupled to a supply of deuterium-containing micro-fusion fuel particles, each reaction volume having at least an upper cover and a bottom opening.

23. The craft as in claim 12, comprising a preassembled habitat ground station that can be launched from and landed intact upon a surface of a planet or moon, the habitat station having at least one reaction volume coupled to a supply of deuterium-containing micro-fusion fuel particles, each reaction volume having at least an upper cover and a bottom opening, each reaction volume providing thrust for propulsion of the habitat station to its destination and also providing electric power and heat for the habitat.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] FIG. 1 is a schematic side view showing an embodiment of an interplanetary craft for operation in the presence of ambient cosmic rays and muons and having micro-fusion generated thrust for lift and propulsion.

[0022] FIG. 2 is a side sectional view showing of the internal reaction chamber of the craft in FIG. 1.

[0023] FIG. 3 is a side sectional view of an internal reaction chamber as in FIG. 2, but with a movable bottom opening for directional selection of escaping reaction products.

[0024] FIG. 4 is a side perspective view of a bottom opening of an internal reaction chamber as in FIG. 2, but having a deflection mechanism for escaping electrically-charged reaction products.

[0025] FIG. 5 is a schematic plan view of a plan for interplanetary travel with successive orbits of different size around source and destination planets or moons and an interplanetary trajectory therebetween.

[0026] FIG. 6 is a schematic top plan view of a craft in the form of a pre-assembled station with multiple reaction chambers for use either as an orbiting space station or as a manufacturing station or habitat station providing crew quarters situated on a planetary or lunar surface.

[0027] FIG. 7 is a graph of cosmic ray flux at the Earth surface versus cosmic ray energy, after very significant cosmic ray absorption by Earth's atmosphere and dust has occurred.

DETAILED DESCRIPTION

[0028] The present invention provides micro-fusion powered craft for interplanetary travel, where the micro-fusion provides thrust for generating both lift from a planetary surface and lateral propulsion. The propulsion technology takes advantage of an abundance of ambient cosmic rays in space and muons generated from such cosmic rays to catalyze fusion events in enough amounts to produce useable thrust. The cosmic rays together with muons are available here for free and do not need to be generated artificially in an accelerator. The thrust also enables single-stage launch from (or landing upon) a lunar or planetary surface, including an ability to haul cargo and personnel up to some maximum weight that is dependent upon the amount of lift and propulsion provided by the micro-fusion. Since the amount of energy needed for thrust is generally much less than the multi-kiloton yields of atomic weapons, micro-fusion is the term used here to refer to fusion energy outputs of not more than 10 gigajoules per second (2.5 tons of TNT equivalent per second), to thereby exclude macro-fusion type explosions.

[0029] A craft is provided with a centrally located internal chamber with a dome on top and opening at the bottom. Deuterium-containing micro-fusion fuel material is inwardly injected at a specified rate into this chamber. Ambient cosmic rays and/or muons penetrate the dome from above and interact with the fuel material to generate energetic alpha particles and/or other reaction products that provide thrust to the craft. In particular, downwardly-directed alpha particles escape through the opening to produce a reaction thrust, while upwardly-directed alpha particles are stopped by the dome and produce applied thrust forces against the craft. Further, any fuel escaping through the bottom opening will also react externally with ambient cosmic rays and muons and the resulting reaction products will apply upward forces upon the underside of the craft. In interplanetary space, there is, of course, no up or down direction. But for convenience of discussion, the dome side of the craft will continue to be referred to as the top of the craft, while the side with the chamber opening will continue to be referred to as the bottom of the craft.

[0030] For lateral motion, the location of the opening at the bottom of the chamber might be moveable so that the selection of which generally downward-directed alpha particles escape and produce reaction thrust can vary. Still further, the bottom opening may have a deflection mechanism (e.g. based on electrostatic fields) that redirects or steers some or all the escaping alpha particles in a more lateral direction. The craft might also be provided with a set of external side ports for lateral motion. Deuterium-containing micro-fusion fuel material is ejected from one or more selected ports to form a cloud of fuel material outside the craft that interacts with the ambient cosmic rays and/or muons. Energetic micro-fusion reaction products interact with the side of the craft to provide lateral thrust moving the craft in a desired direction.

[0031] With reference to FIGS. 1 and 2, a craft 11 has a centrally located internal chamber 13 with a dome 15 on top and an opening 17 at the bottom. The craft 11 therefore constitutes a roughly disk-shaped, toroidal, tubular or doughnut-shaped main body portion 12 surrounding an internal chamber 13 which can extend somewhat above the top of the craft body by means of a bubble region with a dome 15 serving as a cover for the chamber 13. However, neither the central chamber 13 nor the main body portion 12 surrounding the central chamber 13 need be circular or radially symmetric, but could have an oval, elliptical, polygonal, or other odd shape. Cylindrical chambers and disc-shaped main bodies may be preferred for their compactness and economy of material, but other shapes are possible.

[0032] The dome 15 is effectively transparent to cosmic rays, with their extremely high energies (>100 Mev) and penetrating power, but essentially opaque to the substantially lower energy (10 MeV) alpha particle reaction products that will thus be stopped by the dome. It is expected that the dome material can be the same as the external skin 12 of the craft 11, but thinner. However, research and development efforts may optimize the choice of dome material and its thickness to achieve maximum cosmic ray penetration into the chamber 13, as well as to facilitate production of muons through interactions of those cosmic rays with the dome material. The dome 15 might even be double-paned structure with internal wire mesh, fibers and or even fine particulates to enhance muon creation. (Such a double-paned structure may also facilitate the provision of a cooling water or gas flow between the panes.) Such the presence of muon generators as a permanent structure of the dome 15 will lessen or even eliminate the need for having muon-generating particulate material within the fuel, thereby saving valuable fuel weight.

[0033] Additionally, the amount of curvature of the dome may be important to maximizing input of cosmic rays and muons into the chamber 13. The curvature of the dome may range from being completely flat to extending considerably upward above the top of the remainder of the craft 11, perhaps as much as twice as high as its radius. The much larger surface area of a large curvature dome 15 would facilitate cooling of the cover as it bombarded with ambient cosmic rays penetrating from outside and with micro-fusion reaction products (energetic alpha particles ) from within. A larger curvature might also allow relief of mechanical stresses from any heating that does result.

[0034] Except for fuel injection ports 19 leading into the chamber 13, the internal chamber is otherwise isolated from the rest of the craft 11 that radially surrounds it. Specifically, the sides 14 of the chamber 13, seen in FIG. 2, preferably provide sufficient radiation shielding to protect the craft's occupants and supplies, as well as stored fuel not yet injected into the chamber 13.

[0035] One or more fuel injection ports 19 are positioned in the sides 14 of the chamber 13 for ejecting micro-fusion fuel particles 25 from a stored supply 21 to create a cloud 27 of such material within the chamber 13. Ambient cosmic rays 29 and muons p generated from those cosmic rays penetrate the dome 15 and react with the cloud 27 of micro-fusion material to generate energetic fusion products, such as alpha particles . At least some of these energetic fusion products are received by the craft 11 to provide upward thrust or lift. Specifically, some of the alpha particles will be directed downward and escape through the opening 17 at the bottom of the chamber. These will provide an upward reaction thrust. Other alpha particles will be directed upward and be stopped by the dome 15. These will produce an upward applied thrust force against the craft 11. Alpha particles directed laterally in all directions will provide counteracting effects and negligible thrust contributions. Some of the deuterium-containing micro-fusion fuel material will also escape through the opening 17 in the bottom of the chamber 13. However, immediately outside the craft 11, such fuel will also interact with ambient cosmic rays and muons to generate micro-fusion reaction products (alpha particles ) at least some of which will be directed upward onto the underside of the craft 11. These will likewise apply an upward thrust force upon the craft 11. The combination of contributing upward forces will produce lift.

[0036] With reference to FIG. 3, a way to produce lateral thrust might be to have the bottom opening 17a in the chamber 13 be laterally moveable. For example, a plate 18 with the opening 17a therein might slide in a reciprocating (or even rotating) motion Y along the underside of the main craft body 12. Only certain alpha particles traveling in a selected partially lateral trajectory can escape through the opening 17a, depending on its position, so that a preferential lateral thrust Vy is produced.

[0037] With reference to FIG. 4, in a further way of producing lateral thrust, because alpha particles have an electric charge, a deflection mechanism 45 at the bottom opening 17b of the chamber 13 can deflect or steer the alpha particles and give them a lateral component of motion. For example, one mechanism for deflecting alpha particle exhaust can create an electric field using a set of tungsten rods 47, each having a different selected voltage. The voltage differential creates a lateral field that deflects alpha particles traversing the space between those rods 47. The alpha particles have a positive charge whose trajectory is influenced by the lateral electric field. The size and direction of that field can be varied by changing the voltages applied to the various rods 47, thereby varying the field. The amount of electricity required for deflection should be relatively small.

[0038] Returning to FIG. 1, the craft 11 may also have a set of side ports 33 located at various places around the craft. Selected side ports 33 eject micro-fusion particle material 35 to form a cloud 37 that likewise interacts with the ambient cosmic rays 29 and muons p to produce energetic micro-fusion products, such as alpha particles , at least some of which are then received by that side of the craft 11 to provide lateral thrust in a desired direction. Selection of one or more side ports 33 change the direction of lateral movement. Also, if the craft can rotate, then fewer side ports 33 may be needed to achieve the same range of desired lateral movement.

[0039] Using any of these methods a pilot can vary the speed and direction of the craft 11 by varying the amount and direction of lateral thrust provided by the alpha particles.

[0040] In a similar manner, the craft 11 could further include a supplemental supply of deuterium-containing micro-fusion fuel particles that can be propelled externally below an underside of the craft (e.g. from ports like the side ports 33, but located instead on the underside of the craft) so as to interact with ambient cosmic rays and muons external to the craft to produce reaction products having kinetic energy. The additional upwardly directed portion of these reaction products will thus apply additional upward thrust upon the underside of the craft 11.

[0041] The fuel can be solid Li.sup.6D in powder form, D-D or D-T inertial-confinement-fusion-type pellets, or D.sub.2O ice crystals, or even droplets of (initially liquid) D.sub.2. Various types of micro-fusion reactions may also occur, such as Li.sup.6-D reactions, generally from direct cosmic ray collisions, as well as D-T, using tritium generated by cosmic rays impacting the lithium-6. D-T reactions especially may be assisted by muon-catalyzed fusion.

[0042] Muon-created muonic deuterium can come much closer to the nucleus of a similar neighboring atom with a probability of fusing deuterium nuclei, releasing energy. Once a muonic molecule is formed, fusion proceeds extremely rapidly (10-10 sec). One cosmic ray particle moving through the atmosphere and dust can generate hundreds of muons, and each muon can typically catalyze about 100 micro-fusion reactions before it decays (the exact number depending on the muon sticking cross-section to any helium fusion products).

[0043] Besides D-D micro-fusion reactions, other types of micro-fusion reactions may also occur (e.g. D-T, using tritium generated by cosmic rays impacting the lithium-6; as well as Li.sup.6-D reactions from direct cosmic ray collisions). In the reaction, Li.sup.6+D.fwdarw.2He.sup.4+22.4 MeV, much of the useful excess energy is carried as kinetic energy of the two helium nuclei (alpha particles). For this latter reaction, it should be noted that naturally occurring lithium can have an isotopic composition ranging anywhere from as little as 1.899% to about 7.794% Li.sup.6, with most samples falling around 7.4% to 7.6% Li.sup.6. Although LiD that has been made from natural lithium sources can be used in lower thrust applications or to inhibit a runaway macro-fusion event, fuel material that has been enriched with greater proportions of Li.sup.6 is preferable for achieving greater thrust and efficiency.

[0044] Additionally, any remaining cosmic rays after their travel through space can themselves directly stimulate micro-fusion events by particle-target fusion, wherein the high energy cosmic ray particles (mostly protons, but also helium nuclei) bombard relatively stationary target material. When bombarded directly with cosmic rays, the lithium-6 may be transmuted into tritium which could form the basis for some D-T micro-fusion reactions. Although D-D micro-fusion reactions occur at a rate only 1% of D-T micro-fusion, and produce only 20% of the energy by comparison, the freely available flux of cosmic rays and their generated muons should be sufficient to yield sufficient micro-fusion energy output for practical use.

[0045] The dispersed cloud of micro-fusion target material will be exposed to ambient cosmic rays and muons. To assist muon formation, the micro-fusion fuel material may contain up to 20% by weight of added particles of fine sand or dust. As cosmic rays collide with the micro-fusion material and dust, they form muons p that are captured by the deuterium and that catalyze fusion. Muon formation may also be facilitated by reaction of cosmic rays with the dome material. Likewise, the cosmic ray collisions themselves can directly trigger particle-target micro-fusion.

[0046] The amount of energy generated by the micro-fusion reactions, and the thrust the micro-fusion products produce, depends upon the quantity of fuel injected into the chamber 13 and the quantity of available cosmic rays and muons in the ambient environment that can enter the craft through the dome 15. Assuming much of the energy can be captured and made available for thrust, an estimated 10.sup.15 individual micro-fusion reactions (less than 1 g of fuel consumed) per second would be required for 1 kW output. But as each cosmic ray can create hundreds of muons and each muon can catalyze about 100 reactions, the available cosmic ray flux in interplanetary space (believed to be several orders of magnitude greater than on Earth) is believed to be sufficient for this thrust purpose following research, development, and engineering efforts.

[0047] It is noted that as a craft is enlarged in its design, the potential energy output tends to scale as the square of the central reaction chamber's diameter, while the bulk of the craft's mass, located mainly in the disk main body surrounding the chamber, tends to scale only linearly according to the craft's circumference. As such, the craft may be scaled up to large enough dimensions to even become capable of single-stage launch from a planetary surface. Thrust need only exceed the force of gravity for that purpose.

[0048] The micro-fusion fuel material may be sprayed continuously as needed to sustain the fuel clouds both within the chamber 13 and externally adjacent to the craft 11. For the external side ports 33, the fuel can also be ejected in the form of projectiles. The projectiles would then chemically explode when they reach a desired distance from the craft 11 to disperse their micro-fusion particle fuel load and create the external fuel cloud. The amount of micro-fusion target material expended is quite small, since less than 1 g of fuel material reacted per second would be required for 1 kW output. Exact amount of fuel needed will depend upon the ambient cosmic ray and muon flux and the reaction cross-sections for achieving the desired number (e.g. 10.sup.15) of reactions per second.

[0049] The volume of the continuous slow fusion creates high velocity fusion products (fast alpha particles or helium wind, etc.) that bombard the exterior of the craft. The energetic alpha particle micro-fusion products (a) provide thrust against the craft.

[0050] Stored fuel material 21 will be shielded within the craft 11 to reduce or eliminate premature micro-fusion events until delivered and dispersed as a fuel cloud within the interior chamber or outside the craft for thrusting. An inter-planetary astronaut crew will itself need shielding from radiation (which can cause brain damage and other adverse health effects). Therefore, the crew's shielding in the main body or disk section of the craft could double as a shield for the fuel material. One important source of such shielding will be the spacecraft's water supply, which should be adequate for the task. One need not completely eliminate cosmic rays or their secondary particles (pions, muons, etc.) to zero, but merely reduce their numbers and energies sufficiently to keep them from catalyzing sufficiently large numbers of fusion events in the stored target particle material. Additionally, since the use of micro-fusion fuel is expected to reduce the required amount of chemical rocket propellant by a factor of about two, one can easily afford the extra weight of some small amount of metal for shielding, if needed. (For example, the Juno spacecraft to Jupiter contains radiation vaults of 1 cm thick titanium to shield its electronics from external radiation. A similar type of vault might be used in this case for the shielding of the stored fuel.) After being shot from the spacecraft, the casing of the projectiles themselves will continue to provide some shielding until dispersal of the target particle material as a cloud.

[0051] A goal of the invention is to shorten the travel time to Mars or other planets and their moons (to reduce cumulative radiation doses to which the astronauts are subject) and likewise to provide a continuous acceleration or deceleration to offset or reduce weightlessness during the journey. Cosmic ray flux naturally present in interstellar space is used to power nuclear micro-fusion events (via particle-target micro-fusion and muon-catalyzed micro-fusion) that will propel the spacecraft, as well as generate electrical energy. Avoiding a weightless coasting phase of an interplanetary trajectory accomplishes the goal of both shorter travel times and providing an artificial gravity via the accelerating or decelerating thrust of the spacecraft.

[0052] With reference to FIG. 5, a source planet 51 (e.g. Earth) is launch point (a) for a craft 53 constructed and operated in accord with the present invention. Since from recent measurements it is known that muon flux on Earth varies with altitude, it may be discovered after further research to preferably launch spacecraft 53 with this type of propulsion from airfields situated at higher altitudes (e.g. 1500 to 3000 meters). After launch, the craft may climb into a set (b), (c), (d) of ever-increasing orbits 55 about the planet 51 before insertion into an interplanetary or planetary-lunar trajectory 57. As seen at (e), the craft can continue to provide thrust during its travel along the trajectory 57. The craft enters a series of successively smaller orbits 59 around a destination 61 planet (e.g. Mars) or moon (e.g. Earth's own Moon, or Phobos or Deimos of Mars), as represented by (f), (g) and (h) until it lands at (i) upon the surface of its destination planet or moon 61. The craft can be oriented to provide thrust in the desired direction to either speed up or slow down as needed.

[0053] With reference to FIG. 6, a preassembled station 63 will have at least one central reaction chamber 65 surrounded by a main body 69. However, there may also be other reaction chambers, e.g. 67A, 67B, 67C, attached to the station 63. Multiple structural bodies, e.g. 71A, 71B, 71C, will surround the respective chambers 67A, 67, 67C. All of the bodies may be interconnected and structurally reinforced using various passageways 73. The interior of the bodies 69, 71A, 71B, 71C, etc. form crew quarters, working space, and equipment for operation of a space station, manufacturing station or habitat ground station. The station 63 can be launched and transported to a destination orbit or planetary/lunar surface using the micro-fusion generated propulsion from the reaction chambers. Because the amount of thrust can be controlled and sustained for long periods and, unlike chemical propulsion, not fully expended in short-term bursts of high impulse, a single-stage launch can be achieved as the craft slowly lifts itself into orbit, is transported to its destination planet or moon, and descends to a soft landing. A craft in the form of a space station, manufacturing ground station, or habitat station, can be designed and preassembled, then launched and landed intact upon the surface of a planet or moon. The reactor(s) can serve not only to provide steady propulsion, but also (at a lower level) provide electric power and heat for the habitat.

[0054] Because the technology is still early in a developmental phase, testing of its concepts might be perfected at some locations on Earth before its deployment in outer space, even though the ambient flux of cosmic rays and muons may be much lower due to Earth's geomagnetic field and thick atmosphere. Testing with craft at convenient higher altitude Earth locations would allow designers to improve the proposed micro-fusion engines before their use in traveling to and from the Moon, and then Mars. (Both cosmic ray flux and muon generation are known to substantially increase with altitude.) When used on Earth, some care will be needed when using some micro-fusion fuels. For example, lithium hydride (including Li.sup.6D) is known to be violently chemically reactive in the presence of water. While reactions with water are not a problem on the Moon or Mars, with any Earth applications the fuel material will need to be encapsulated to isolate it from water sources, including atmospheric vapor. A desiccant can also be used when storing the fuel material.