Micro-fusion-powered unmanned craft

Abstract

A craft having a source of deuterium-containing micro-fusion fuel particles is operable above a planetary, lunar or asteroid surface in the presence of ambient cosmic rays. The fuel particles are dispersible from a set of ports, where at least some of the ports are in an underside of the craft body and others are in lateral sides of the craft body. Dispersed fuel particles interact with ambient cosmic rays and muons to generate energetic reaction products, at least some which are then received by the underside of the craft to generate lift and also selected lateral sides of the craft to generate propulsive thrust in a desired lateral direction. The craft can carry tethers and winches to carry a payload above the surface from location to another. In another embodiment, a balloon-based design, such as a dirigible, provides primary buoyant lift, while the micro-fusion particles provide at least lateral thrust, and supplemental lift where needed.

Claims

1. A craft operable above a lunar or asteroid surface in the presence of ambient cosmic rays, comprising: a craft body having therein a source of deuterium-containing micro-fusion fuel particles, the total mass of the craft including fuel being at most 25 kilograms, the fuel particles being dispersible from a set of ports in the craft body, at least some of the ports being in an underside of the craft body and at least others of the ports being in lateral sides of the craft body, dispersed fuel particles interacting with ambient cosmic rays and muons produced from the cosmic rays to generate energetic reaction products, at least some of the reaction products being received by the underside of the craft body to generate lift and at least some of the reaction products being received by selected lateral sides of the craft body to generate propulsive thrust of the craft body in a desired lateral direction.

2. The craft as in claim 1, wherein a set of tethers are attached to the craft body for carrying a load of up to 15 kilograms.

3. The craft as in claim 2, wherein the tethers are deployed by a set of winches on the craft body.

4. The craft as in claim 1, wherein the craft body includes communication equipment for receiving remote piloting instructions.

5. The craft as in claim 1, wherein the craft body further includes observational equipment and sensors.

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

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

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

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

10. The craft as in claim 1, wherein the deuterium-containing particle fuel material is in solid chip or pellet form.

11. The craft as in claim 1, wherein the deuterium-containing particle fuel material is encapsulated to isolate the material from ambient sources of water.

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

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

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

15. A craft operable above a surface of a planet having an atmosphere in the presence of ambient cosmic rays and muons, comprising: a balloon-type body containing a gas or near vacuum within an interior with a density of less than a planetary atmosphere outside the balloon-type body so as to provide buoyant lift; a source of deuterium-containing micro-fusion fuel particles carried by the balloon-type body, the fuel particles being dispersible from a set of ports in the balloon-type body, at least some of the ports being in lateral sides of the balloon-type body, dispersed fuel particles interacting with ambient cosmic rays and muons produced from the cosmic rays to generate energetic reaction products, at least some of the reaction products being received by selected lateral sides of the balloon-type body to generate propulsive thrust in a desired lateral direction.

16. The craft as in claim 15, wherein the balloon-type body comprises a dirigible.

17. The craft as in claim 15, wherein at least some of the ports are on an underside of the balloon-type body and at least some of the reaction products being received by the underside of the balloon-type body to generate supplemental lift in addition to the buoyancy lift of the balloon-type body.

18. The craft as in claim 15, wherein a set of tethers are attached to the balloon-type body for carrying a load.

19. The craft as in claim 18, wherein the tethers are deployed by a set of winches on the balloon-type body.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a schematic side view showing an embodiment of a craft for operation above a planet's or moon's surface in the presence of ambient cosmic rays and muons and having micro-fusion generated thrust for lift and propulsion.

(2) FIG. 2 is a schematic side view showing use of a craft such that in FIG. 1 for transport of cargo.

(3) FIG. 3 is a schematic side view showing an alternate embodiment of a craft having a balloon-based design, such as a dirigible, for primary lift and with micro-fusion generated propulsion and supplemental lift.

(4) FIG. 4 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

(5) With reference to FIG. 1, a craft 11 has a set of lower ports 13 for ejecting micro-fusion particles 15 downward to create a cloud 17 of such material. Ambient cosmic rays 19 and muons generated from those cosmic rays react with the cloud 17 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. The craft 11 also has a set of side ports 23 located at various places around the craft. Selected side ports 23 eject micro-fusion particle material 25 to form a cloud 27 that likewise interacts with the ambient cosmic rays 19 and muons 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 23 change the direction of lateral movement. Alternatively, if the craft can rotate, then fewer side ports 23 may be needed to achieve the same range of desired lateral movement. The craft 11 may also have a set of tethers 31 (here, two of them are shown), which may be attached at the vehicle end to winches 33 and attached at a lower end (not shown) to a payload receptacle or the payload itself.

(6) As seen in FIG. 2, a craft 41 is seen with tethers 43 holding a receptacle 45 with a payload. Clouds of micro-fusion particle material 47 are ejected from the craft 41 to provide lift and forward propulsion in a direction 49. The craft 41 travels above the surface 51 of a planet, moon, asteroid or other space body, e.g. toward a base 53 to which the payload is being delivered.

(7) In addition to delivery of payload material to some desired destination, micro-fusion-powered crafts of this sort can be used for overhead observation or reconnaissance of the planetary or lunar surface. The crafts can either hover above a stationary location (e.g. when only the lower ports are used to create lift) or move in a regular search pattern over the surface (e.g. using the side ports to create propulsion). The weight of such vehicles can often be less than 5 kg, so that it doesn't need much lifting thrust to remain airborne at a specified altitude above the lunar or planetary surface for reconnaissance purposes. The thrust-to-weight will be approximately 1 to achieve stable altitude but can be increased or decreased several-fold as needed to gain or lower the craft's altitude.

(8) 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.

(9) 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 that are captured by the deuterium and that catalyze fusion. Likewise, the cosmic ray collisions themselves can directly trigger particle-target micro-fusion.

(10) The amount of energy generated by the micro-fusion reactions, and the thrust the micro-fusion products produce, depends upon the quantity of fuel released and the quantity of available cosmic rays and muons in the ambient environment surrounding the craft. Assuming most 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 (known 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.

(11) The micro-fusion fuel material may be sprayed continuously as needed to sustain the cloud underneath the craft, or alternatively can be shot out as a series of small projectiles containing the micro-fusion target material, e.g. once every minute or more frequently. The projectiles would then chemically explode when it reaches a desired distance from the craft to disperse its micro-fusion particle fuel load and create the cloud. A hovering craft would perhaps need less fuel for creating lift since the cloud will tend to remain longer below the craft until it eventually disperses. A moving craft should have its lift generating material sprayed or shot below but slightly ahead of the craft to remain under the craft for a longer time as the craft moves over the cloud. The amount of micro-fusion target material expended is still 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.

(12) 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 () provide thrust against the craft. If needed a large-diameter flat disc or pressure plate can be mounted on the craft to receive the fusion products to maximize thrusting from such direct interactions with the fusion products. Even the photon radiation generated in the micro-fusion reactions will apply some supplemental thrusting pressure to the craft.

(13) Stored fuel will be shielded within the craft to reduce or eliminate premature micro-fusion events until delivered and dispersed as a cloud outside the craft for thrusting. However, 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 large numbers of micro-fusion events in the stored target particle material.

(14) The muon-catalyzed and direct particle-target micro-fusion for providing the thrust may be used on the Moon, Mars, Martian moons, or even possibly asteroids. Simple, inexpensive observation drones can be operated at a variety of altitudes and speeds. The design can be optimized for the particular space body. Specifically, as in FIG. 1, each craft could have two sources of micro-fusion thrust: one to achieve and maintain altitude, and at least one other to provide horizontal motion. Craft designs might typically comprise stacked discs (e.g. 3 to 6), each performing some dedicated function of the craft. In FIG. 1, an upper most portion of the craft might be dedicated to holding communication equipment (antennae and dishes) 55, especially if the craft 11 is intended to be remotely-operated. Other portions of the craft would likely hold sensors and other observational equipment.

(15) Because the technology is still early in a developmental phase, testing of its concepts might be perfected on Earth before deployment in outer space, even though the ambient flux of cosmic rays and muons is several orders of magnitude lower due to Earth's geomagnetic field and thick atmosphere. For testing purposes, ultra-lightweight craft under 5 kg may be used, especially at higher altitudes. (Both cosmic ray flux and muon flux are known to substantially increase with altitude.) Testing with ultra-lightweight craft at convenient higher altitude Earth locations would allow designers to improve the proposed micro-fusion engines before their use on the Moon and then on Mars.

(16) 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.

(17) Micro-fusion powered craft can also serve a role in asteroid mining applications, e.g. to supply deliveries to an asteroid mining base camp, or to move ore samples from an asteroid mining site to the base camp (or to a nearby tethered or orbiting spacecraft) for evaluation. In high muon and cosmic ray environments, there may even be enough thrust for lifting and moving equipment from place to place.

(18) Similar local resource extraction activities are anticipated at Mars colonies. On Mars, there is an additional benefit of some atmosphere such that a balloon-type craft design, such as a dirigible, can be used for primary lift. The key requirement is that the gas contained within the interior of the balloon or dirigible be a lower density in relation to the exterior atmosphere. As reaction with oxygen is less of a danger on Mars and hydrogen can readily be extracted from Martian water ice, hydrogen can be used as the dirigible gas. As seen in FIG. 3, such a balloon-based design has an exterior surface 61 that contains within it the hydrogen gas at the same pressure as the Martian atmosphere (or a lesser pressure if the dirigible or balloon surface material is sufficiently rigid). This provides lift or reduces the need for lift from micro-fusion. If the load being carried is especially heavy, underside ports 63 can disperse micro-fusion fuel 65 to form a cloud 67 that reacts with ambient cosmic rays and muons as before. The energetic micro-fusion reaction products (primarily alpha particles) are received by the craft 61 to achieve additional secondary lifting thrust beyond that provided primarily by the dirigible's buoyancy. In either case, whether micro-fusion lift is needed or not, side ports 73 disperse micro-fusion fuel 75 to form a cloud 77 that again reacts with cosmic rays and muons to generate lateral propulsive thrust to move the craft 61 toward its destination. Again, a set of tethers 81 connected to the craft 61 via corresponding winches 83 can hold a load beneath the dirigible craft 61 or other balloon-based craft.

(19) In a similar application, a balloon-based design could be filled with hydrogen (or helium) and used to raise a small lightweight remotely-piloted (or autonomous) aerial vehicle or drone to an altitude where a planet's cosmic ray and muon flux are at useful levels for achieving micro-fusion thrust. Once that altitude is reached, the balloon may be cut loose (or vented, hauled-in and stored for future use) and the micro-fusion thrust engine started as in FIG. 1.

(20) Helicopter-style aerial vehicles, because of their many moving parts, are prone to failure and crashes. (This susceptibility is likely to be amplified if employed on Mars because the rotor blades will need to move even faster in the much lighter atmosphere.) In the presence of an adequate flux of cosmic rays and muons, the micro-fusion thrusting can be used as an emergency backup to slow the fall of a failing helicopter and soften any crash landing. Thus, it could serve as a safety feature with potential to save lives.

(21) Micro-fusion powered spacecraft with role as a space taxi or crew transfer vehicle, or for cargo delivery, can link up with an orbiting spacecraft. The micro-fusion thrust from a vehicle like that in FIG. 1 can possibly ascend from the Martian surface to one or both of its moons (Phobos and Deimos). Similarly, in the asteroid belt, short voyages between two nearby asteroids might be possible. Also, micro-fusion propulsion can be use for spacecraft maneuvering, collision avoidance, and orbital station-keeping.