ASTEROID MINING SYSTEMS FACILITATED BY COSMIC RAY AND MUON-CATALYZED FUSION

Abstract

Cosmic ray and muon-catalyzed micro-fusion electrical generation provides electrical power for mining operations, including any asteroid habitats and mining equipment. The micro-fusion generator systems deploy deuterium-containing fuel material as a localized cloud interacting with incoming ambient cosmic rays to generate energetic fusion products. Dust or other particulate matter in the fuel material, in the localized cloud, and in the space surrounding the asteroid being mined converts some cosmic rays into muons that also catalyze fusion. The fusion products drive turbines to facilitate the electrical generation.

Claims

1. A micro-fusion-driven turbine generator for producing electricity in the presence of ambient flux of cosmic rays and muons, comprising: a source of deuterium-containing micro-fusion particle fuel material disposed on an asteroid surface; a reaction volume directed upward from the asteroid surface; a flue coupled to the source and reaction volume for dispersing fuel material into the reaction volume; a set of helium-wind turbines arranged around the reaction volume, wherein cosmic rays and muons entering the volume from above interact with the dispersed fuel material to cause nuclear micro-fusion events, kinetic-energy containing micro-fusion products driving the helium-wind turbines; and a set of electrical generators coupled to the respective helium-wind turbines to convert mechanical motion of the driven turbines into electricity.

2. The generator as in claim 1, further comprising an ion thruster powered by the generated electricity for producing thrust upon the asteroid in a specified direction.

3. The generator as in claim 1, wherein the reaction volume is a cylinder with an opening at an upper end to receive the cosmic rays and muons.

4. The generator as in claim 1, wherein the turbines are arranged radially around the circumference of the cylinder reaction volume.

5. The generator as in claim 1, wherein turbines are stacked vertically in multiple layers along a length of the cylinder reaction volume.

6. The generator as in claim 1, wherein one or more fans are provided in the reaction volume to maintain the dispersed fuel material in suspension within the reaction volume.

7. The generator as in claim 1, further comprising electrical power lines connecting the generators to one or more asteroid mining habitations.

8. The generator as in claim 1, wherein the deuterium-containing particle fuel material comprises Li.sup.6D.

9. The generator as in claim 1, wherein the deuterium-containing particle fuel material comprises D.sub.2O.

10. The generator as in claim 1, wherein the deuterium-containing particle fuel material comprises D.sub.2.

11. The generator as in claim 1, wherein the deuterium-containing particle fuel material is in solid powder form.

12. The generator as in claim 1, wherein the deuterium-containing particle fuel material is in pellet form.

13. The generator as in claim 1, wherein the deuterium-containing particle fuel material is in frozen form.

14. The generator as in claim 1, wherein the deuterium-containing particle fuel material is in liquid droplet form.

15. The generator as in claim 1, wherein the deuterium-containing particle fuel material also contain up to 20% by weight of added particles of fine sand or dust.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] FIG. 1 is a schematic plan view of a micro-fusion-driven turbine generator apparatus in accord with the present invention, shown operating on the surface of an asteroid to supply electrical power.

[0017] FIG. 2 is a schematic side view of a micro-fusion-driven turbine generator as in FIG. 1 supplying electricity to asteroid mining habitats.

[0018] FIG. 3 is a top plan view of the reaction volume of the turbine generator apparatus as in FIG. 1 showing an arrangement of turbines and generators circumferentially around a reaction volume.

[0019] FIG. 4 is a side plan view of the reaction volume of a turbine generator apparatus as in FIG. 1 showing the turbines and generators in a vertically stacked arrangement along a length of the reaction volume.

[0020] FIG. 5 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 has occurred.

DETAILED DESCRIPTION

[0021] Cosmic-ray and muon-catalyzed micro-fusion can be employed in the invention to supply electrical power for mining of asteroids (either by automated mining equipment transported to the asteroid, or with assistance of astronaut-miners) and the mined products returned to Earth. 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 generate electrical energy for the mining activity.

[0022] In the embodiment shown in FIG. 1, each engine may have one or more turbine electric generators 41, where the turbines are driven by the fast helium nuclei micro-fusion products generated from dispersed lithium-6 deuteride or other deuterium-containing micro-fusion target material exposed to the cosmic rays. Micro-fusion fuel packages would be delivered to the vicinity of each of the turbines, where the micro-fusion reaction products can turn the turbines to generate electricity for asteroid mining, including powering of mining equipment and powering of ion thrusters to move or redirect asteroids with mining potential. For example, in one embodiment a cloud of deuterium-containing micro-fusion target fuel 43, e.g. particles of Li.sup.6D, is dispersed from a flue 44 into a volume 45 between two or more helium-wind turbines 46. Specifically, a generator assembly 41 includes a source 40 of deuterium-containing micro-fusion particle fuel material 42. This material could be blown 43 through a flue 44 (e.g. by means of a fan with a gas source at the source 40 or by other means depending on the form that the fuel material takes), and then dispersed from the flue 44 into a reaction volume 45.

[0023] The micro-fusion target fuel material 43 is dispersed in proximity to turbines 46 arranged around the reaction volume 45, and then exposed to ambient cosmic rays 49 and muons ? that enters the volume 45 and interacts with the dispersed fuel material 43 to cause nuclear micro-fusion events. High-energy cosmic rays 49 entering the volume 45 interact with the micro-fusion target fuel material 43 to cause nuclear fusion events. Fusion products, mainly high energy helium nuclei (alpha particles), direct kinetic energy to the turbine blades 46 to turn the turbines and generate electricity. A wind of micro-fusion products made up of energetic helium (alpha products) impinge upon and direct kinetic energy to the turbine blades 46 to turn the turbines and drive the associated generators 47 to produce electricity which can then be supplied via electric cables 48 to the habitats and other equipment. A set of one or more fans 50 in the reaction volume 45 may help keep the fuel material in suspension near the turbines 46.

[0024] The micro-fusion electrical generator system works in the presence of an ambient flux of cosmic rays and/or muons which interact with the cloud and trigger the nuclear micro-fusion of the particle target material, either by particle-target micro-fusion or muon-catalyzed micro-fusion or both. The micro-fusion fuel releases as a cloud and can be solid Li.sup.6D in powder form, D-D or D-T inertial-confinement-fusion-type pellets, D.sub.2O ice crystals, or droplets of (initially liquid) D.sub.2.

[0025] The deuterium fuel for a generator may be supplied in the form of clouds of solid lithium-6 deuteride powder, pellets or chips, or even frozen heavy water (D.sub.2O) or liquid droplets of D.sub.2, to a reaction chamber 45, where it is exposed to incoming cosmic rays 49 and muons i, as seen in FIG. 1. One technique for creating the cloud of fusion target material is to shoot fuel packages as a series of projectiles into the reaction chamber, which can then disperse the fusion material as a localized cloud, much like fireworks or artillery. For this purpose, one or more gun tubes may be located below the chamber and loaded with the packages for introduction into the chamber. Alternatively, packages may be dropped into the chamber from near the top via a slide dispenser. The fuel within the projectile packages 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. To assist muon formation, especially when D.sub.2O is used, the target package may contain up to 20% by weight of added particles of fine sand or dust. Packages will be shielded, at least within the casing of the projectiles themselves, to reduce or eliminate premature fusion events until delivered and dispersed as a cloud in the reaction chamber. Soon after the projectile has reached the desired dispersal location within the chamber, the package releases its target material. For example, a chemical explosion can be used to locally disperse the fusion material. For a typical cloud of Li.sup.6D in powder form it may be desired to disperse the material near the top of the chamber to allow maximum usage of the material while it settles toward the bottom of the chamber. In the case of very large asteroids, it might be advantageous to provide one or more fans 50 at the bottom of the chamber 45 (seen in FIG. 1) to keep the cloud of target material suspended in the chamber as long as possible, but most asteroids will have sufficiently low, even negligible, gravity so that the micro-fusion fuel material settling too rapidly would not be a concern.

[0026] The dispersed cloud of target material will be exposed to both cosmic rays and to their generated muons. To assist in the formation of muons for muon-catalyzed fusion, especially when D.sub.2O or D.sub.2 is used, the target package may contain up to 20% by weight of added particles of fine sand or dust. As cosmic rays collide with both micro-fusion target material and dust, they form muons that are captured by the deuterium and that catalyze micro-fusion. Likewise, the cosmic ray collisions themselves can directly trigger particle-target micro-fusion. Fusion products having significant kinetic energy (e.g. alpha particles) are generated and are received by turbines.

[0027] 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). 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 could also be used, fuel material that has been enriched with greater proportions of Li.sup.6 is preferable for achieving greater efficiency.

[0028] Stored fuel packages associated with the attached generator will be shielded to reduce or eliminate premature fusion events until delivered and dispersed as a cloud in the chamber. Some small amount of metal for fuel storage unit could be used 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.) Alternatively, another possible source of such shielding might include the astronaut-miners' own water supply (if part of a manned mission), which should be adequate for the task. One need not 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.

[0029] The rate of fuel usage will depend on the amount of electricity required, the amount of fusion obtained from the ambient cosmic ray and/or muon flux, the dispersal rate of the fuel cloud from the chamber and the efficiency of the transfer of the fusion products into turbine rotation. Assuming most of the energy can be captured, 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 100 micro-fusion reactions, the available cosmic ray flux in interplanetary space is believed to be sufficient for this purpose following research, development, and engineering efforts.

[0030] For very large asteroids (i.e. dwarf planets or slightly smaller) that cannot be redirected but must be mined in their current location, FIG. 2 shows the turbine electric generator apparatus 41 located on the asteroid surface 11, where the generators are powered by reaction of ambient cosmic rays and muons with a dispersed cloud of micro-fusion fuel within a reaction volume of the apparatus 41. Electrical power lines 48 lead from the generator apparatus 41 to various mining habitats for manned mining missions. Some habitats (depending on the composition of the asteroid) might be underground, as in habitat 52, which might be accessible via a stairwell 53. Electrical power lines 48 could feed electricity to the habitat 52 via conduits along the same access column that supports the stairwell. Other habitats might be above ground, as in habitat 55, powered by electricity supplied via external power lines 48. If the asteroid is too small for habitation, the astronaut abode is their spacecraft, while the generator apparatus still supports mining operations by providing electrical power for the mining equipment. In accord with the invention, the generator apparatus 41 has turbines driven by fast helium nuclei micro-fusion products generated from dispersed lithium-6 deuteride or other deuterium-containing micro-fusion target material exposed to the cosmic rays and muons.

[0031] As seen in FIGS. 1 and 2, the chamber may be arranged with its cylindrical or columnar axis pointing in a vertical direction, since cosmic rays and generated muons will be arriving from above, and the asteroid itself will shield in-coming cosmic rays from below, such that the chamber should be located and pointed in a direction that maximizes receipt of cosmic rays onto the cloud of fusion target material within the chamber.

[0032] As seen in FIG. 3, the turbines 46 may be arranged around the circumference of the reaction volume 45, which can be cylindrical or any other equivalent columnar shape. While typically four in number, there can anywhere from as few as two up to 20 or more such turbines 46 (eight are seen here), depending on the space available, the size of the fusion reaction cloud, and the size and arrangement of the turbines themselves about the chamber 45. Alternatively, or in addition, as seen in FIG. 4, the turbines 46 may be arranged in multiple stacks along the length of the cylindrical reaction volume 45. Turbines are connected, e.g. through gearboxes, to corresponding induction generators 47. The generators 47 may be equal in number to the corresponding turbines 46 (1:1 correspondence), or multiple turbines may drive any given generator (n:1 correspondence).

[0033] The present invention achieves nuclear micro-fusion using deuterium-containing target material, and the ambient flux of cosmic rays and generated muons that are already naturally present. The dispersed cloud of target material will be exposed to both cosmic rays and to their generated muons. As cosmic rays collide with fusion targets and dust, they form muons that are captured by the deuterium and that catalyze fusion. Likewise, the cosmic ray collisions themselves can directly trigger particle-target fusion. Muonic deuterium, tritium or lithium-6 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 (on the order of 10.sup.?10 sec). One cosmic ray particle can generate hundreds of muons, and each muon can typically catalyze about 100 fusion reactions before it decays (the exact number depending on the muon sticking cross-section to any helium fusion products). For example, a particularly desired reaction is Li.sup.6+D.fwdarw.2He.sup.4+22.4 MeV, where much of the useful excess energy is carried as kinetic energy of the two helium nuclei (alpha particles). The alpha particles then provide a motive force to turbine blades for the generation of electricity. Other fusion reactions also create. energetic fusion products that can drive the turbines.

[0034] Additionally, any remaining cosmic rays can themselves directly stimulate a fusion event by particle-target fusion, wherein the high energy cosmic ray particles (mostly protons, but also helium nuclei) bombard the cloud of target material. When bombarded directly with cosmic rays, the lithium may be transmuted into tritium which could form the basis for some D-T fusion reactions. Although D-D fusion reactions occur at a rate only 1% of D-T 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 fusion energy output for practical use.

[0035] The optimum concentration of the cloud of target material for the particle-target and muon-catalyzed fusion may be determined experimentally based on the particular abundance of cosmic rays with a view to maintaining a chain reaction of fusion events for producing adequate thrust against the turbine blades, while avoiding any possibility of runaway fusion.

[0036] The present invention achieves muon-catalyzed nuclear fusion using deuterium-containing target material, and muons that are naturally created from ambient cosmic rays. Most cosmic rays are energetic enough to create multiple muons (often several hundred) by successive collisions with dust or with the atoms in a target. In fact, most cosmic rays have GeV energies, although some extremely energetic ones can exceed 10.sup.18 eV and therefore potentially generate millions of muons. The optimum concentration of the target material for the muon-catalyzed fusion may be determined experimentally based on the particular abundance of cosmic rays with a view to maintaining a chain reaction of fusion events for driving the electrical generating turbines.

[0037] Because both particle-target fusion and muon-catalyzed fusion, while recognized scientifically, are still experimentally immature technologies (since measurements have only been conducted to date on Earth using artificially accelerated particles and generated muons from particle accelerators), various embodiments of the present invention can have research utility to demonstrate feasibility in environments beyond Earth's protective atmosphere and/or geomagnetic field. First, a satellite platform in Earth orbit (for example, on the International Space Station) and then later a lander on the surface of the Moon are both conveniently close to Earth to place experimental modules in order to determine optimum parameters (e.g. dimensions of the chamber, and cloud density for different fuel types) in order to adequately drive the turbines.