Asteroid redirection and soft landing facilitated by cosmic ray and muon-catalyzed fusion

Abstract

Asteroid redirection and soft-landing systems are provided that use cosmic ray and muon-catalyzed micro-fusion. These systems include a micro-fusion propulsion system providing thrust for redirecting a small asteroid, as well as providing a particle cushion at a landing site for a soft-landing. The 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 converts some cosmic rays into muons that also catalyze fusion. The fusion products provide thrusting upon the asteroid. The fusion products also aid deceleration of incoming asteroids to be mined for a soft landing upon a lunar or planetary surface.

Claims

1. A method, operable in the presence of an ambient flux of cosmic rays, of braking an asteroid upon approach to a lunar or planetary surface, comprising: projecting deuterium-containing particle fuel material in a specified direction outward from a landing site on a lunar or planetary surface toward an approaching asteroid, the asteroid having a mass of not more than 100 metric tons, the asteroid also provided with its own onboard propulsion system, dispersing the material as a cloud directly in an incoming flight path of the asteroid, the material interacting with the ambient flux of cosmic rays to generate products having kinetic energy; and receiving by the asteroid of at least some portion of the generated kinetic-energy-containing products to produce thrust directed generally away from the lunar or planetary surface that decelerates the asteroid as it approaches the landing site at a specified trajectory.

2. The method as in claim 1, wherein the deuterium-containing particle fuel material is projected from a pre-positioned system at the landing site to a specified location outward from the asteroid such that the generated kinetic-energy-containing products pushing against the asteroid produce braking thrust according to a desired asteroid trajectory toward the landing site.

3. The method as in claim 2, wherein the pre-positioned landing site further includes radar tracking equipment for determining position, velocity, and trajectory of the asteroid as it approaches the landing site and directs the projecting of the fuel material to a calculated location in relation to the approaching asteroid.

4. The method as in claim 2, wherein the pre-positioned system also disperses a cloud of the deuterium-containing particle fuel material in the immediate vicinity of the landing site such that generated kinetic-energy-containing products create a braking cushion at the landing site.

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

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

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

8. The propulsion system as in claim 1, wherein the deuterium-containing particle fuel material is in solid powder form.

9. The propulsion system as in claim 1, wherein the deuterium-containing particle fuel material is in pellet form.

10. The propulsion system as in claim 1, wherein the deuterium-containing particle fuel material is in frozen form.

11. The propulsion system as in claim 1, wherein the deuterium-containing particle fuel material is in liquid droplet form.

12. The propulsion system 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.

13. The propulsion system as in claim 1, wherein the deuterium-containing particle fuel material is projected outward from the landing site as successive packages.

14. The propulsion system as in claim 13, wherein each package is configured to disperse the deuterium-containing particle fuel material as localized cloud at a specified distance from the asteroid.

15. The propulsion system as in claim 1, wherein each landing site has at least one gun and a set of shell projectiles to be shot from the at least one gun to target areas for fuel material dispersal.

16. The propulsion system as in claim 15, wherein the shell projectiles contain a chemical explosive and a fuse configured to disperse the fuel material as a localized cloud at a specified distance from the asteroid.

17. The propulsion system as in claim 15 wherein each shell projectile comprises a shell wall encasing the fuel material with a fuse and chemical explosive charge activated by the fuse.

18. The propulsion system as in claim 17, wherein the shell projectile further comprises a cartridge case containing a propellant for projecting the shell to a targeted location.

19. The propulsion system as in claim 17, wherein the fuse comprises a timer for activating the explosive charge at a specified time after projection of the shell.

20. The propulsion system as in claim 17 wherein the fuse comprises a location detection system for activating the explosive charge when the shell reaches a targeted location.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a side plan view of a thrust engine attached to an asteroid surface showing deployment of micro-fusion fuel via projectiles.

(2) FIG. 2 is schematic sectional view of one possible projectile package or shell for containing and dispersing the micro-fusion fuel material.

(3) FIG. 3 is schematic side view of an automated soft-landing system based on pre-positioned equipment at a landing site for guiding and facilitating landing of incoming small asteroids.

(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) Cosmic-ray and muon-catalyzed micro-fusion can be employed in the invention in one of several ways. One is to shorten travel time to an asteroid in near-Earth orbit, the asteroid belt between Mars and Jupiter and elsewhere in our solar system. Upon arrival, mining of the asteroid can proceed (either by automated mining equipment transported to the asteroid, or with assistance of astronaut-miners) and the mined products returned to Earth. Alternatively, the asteroid can be redirected to a location closer to Earth, such as in lunar orbit, or (if the asteroid is small enough) even soft landed upon the Moon. 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 spacecraft to the asteroids, propel those asteroids with mining potential closer to Earth, as well as generate electrical energy for the mining activity.

(6) With reference to FIG. 1, one propulsion technique to propel an asteroid upon a desired trajectory, is to project the micro-fusion target material in a specified direction outward from the asteroid surface 11, i.e. toward the rear of its intended trajectory from a set of gun-like engines 13 attached at various points onto the asteroid 11. The engines 13 have a supply vault 14 for the projectiles 15 and a gun 16 for firing them outward. For example, one may shoot fuel packages (chips, pellets, powder) loaded in a series of projectiles 15, at a specified rate (e.g. once per second), which can then disperse the micro-fusion material as a localized cloud 17, much like artillery from an antiaircraft gun or the shooting of fireworks.

(7) The space propulsion system works in the presence of an ambient flux 19 of cosmic rays and/or muons which interact with the cloud 17 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 17 from the projectiles 15 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. Fusion products 21 having significant kinetic energy (e.g. alpha particles) are generated and are received upon the asteroid surface 11 to produce thrust against the asteroid. The thrust results in acceleration (or deceleration) of the asteroid along a specified trajectory.

(8) Stored fuel packages 15 associated with the attached engine 13 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 adjacent to the asteroid. Some small amount of metal for the engine 13 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 14 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. After being shot from the gun 16, the casing of the projectiles 15 themselves will continue to provide some shielding until dispersal of the target particle material as a cloud 17.

(9) A variety of known pyrotechnic or artillery shell structures might be employed, the difference being in the content of the material to be dispersed. As seen in FIG. 2, one possible structure comprises a shell 15 having a shell wall 23 containing the micro-fusion fuel material 31 and attached at the back to a cartridge case 25 with solid-chemical-fuel propellant 27 for launching the shell to a targeted location. Within the shell wall 23, for example at or near its tip is a fuse 33 for triggering the release and dispersal of the material 31, e.g. by explosive means including a central ignition tube 34 leading to a shell-bursting charge 35. The fuse 33 can be based upon timing, barometric pressure, a determined position, or other known mechanisms to ensure that dispersal of the fuel material 31 occurs at an optimal altitude over the targeted location.

(10) Soon after the projectile has reached a desired distance from the asteroid the fuel package releases its particle target material. For example, a chemical explosion can be used to locally disperse the micro-fusion material. The shells or other form of package should disperse the micro-fusion fuel elements at a desired altitude (i.e. distance from the asteroid surface) for optimal dispersal of the fuel material relative to the asteroid. Various mechanisms for triggering a chemical explosion of the package could be employed. Triggering technologies can include any one or more of (1) a timer, (2) a location detector, or (3) laser or microwave beam(s) directed at the package from one or more surface bases or nearby spacecraft. Optimal distance for dispersing the material may depend upon asteroid size and composition.

(11) 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.

(12) 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 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.

(13) The micro-fusion reactions in the dispersed cloud creates a kind of external combustion engine that will provide thrust against one side of the asteroid. The asteroid effectively acts as the equivalent of a piston in an external combustion engine and the volume of the continuous slow micro-fusion creates high velocity fusion products (alpha particles, etc.) that bombard the asteroid surface. Even the photon radiation generated by micro-fusion events supplies pressure to help accelerate the asteroid. The required rate of firing will depend on the amount of acceleration required, the amount of fusion obtained from the ambient cosmic ray and/or muon flux, the dispersal rate of the fuel cloud from in front of the asteroid, and the efficiency of the transfer of the fusion products into thrust, but could be expected to be as much as one shell per second for the duration of the thrusting period. The amount of energy generated depends upon the quantity of fuel released and the quantity of available cosmic rays and muons. 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 100 micro-fusion reactions, the available cosmic ray flux in interplanetary space is believed to be sufficient for this asteroid thrusting purpose following research, development, and engineering efforts.

(14) The number of micro-fusion thrust engines needed will depend upon the size (i.e. mass) of the asteroid to be redirected and upon the acceleration required. Additionally, if the asteroid has any amount of rotation relative to its trajectory, the operation of the various engines will need to be coordinated so that only those engines located (at any given point in time) where they can provide the desired thrust direction are active. When the asteroid rotates, some engines will shut off and others turned on, as needed, to maintain the target thrusting in the correct direction.

(15) With reference to FIG. 3, an automated soft-landing system (providing for human intervention only as a backup or for emergencies) can be based upon the micro-fusion for achieving a soft landing of a small asteroid 71 onto a lunar or planetary surface. As seen, the landing system has been pre-positioned at one or more desired landing sites on the surface. The landing system would include a radar subsystem 73 to track the arriving asteroid 71, precisely measuring its altitude, velocity, trajectory, and rate of change of these parameters. Using those measurements, the landing system could then launch a sequence of micro-fusion fuel packages 76 from a gun 75 near the designated landing site 72. The shell projectile packages 76 are delivered along a trajectory 78 to specified locations directly in the asteroid's incoming flight path 77, then the projectile's contents are dispersed as a cloud 79 of micro-fusion target material to interact with incoming cosmic rays 80 and muons to generate energetic fusion products that produce the desired braking thrust upon the asteroid 71 as it approaches the landing site 72.

(16) Each landing site 72 would have a radar system 73 that emits directed radio energy 74 toward the incoming asteroid 71 and receive the reflected radio signal so as to determine altitude, trajectory, velocity, rate of change and other parameters needed to deliver micro-fusion fuel packages 76 to locations that will get the asteroid 71 safely to its landing site 72. The packages 76 and the micro-fusion fuel cloud 79 they release provide the needed retro-thrust or braking cushion to the asteroid 71. Additionally, the immediate landing site 72 may directly release a cloud 81 of the micro-fusion material to create a retro-thrust landing cushion. The software program and its associated radar tracking equipment 73 and the gun (or guns) 75 directing the projectiles 76 together form an automated landing system that can have AI (e.g. self-learning) features, whereby each landing of an asteroid 71 is evaluated according to specified benchmarks, and then adjusted for subsequent landings to deliver more accurately the shell projectiles 76 that create the micro-fusion braking cushions 79 and 81. For example, the system may have the benefit of cosmic ray or muon flux measurements during a landing sequence and need to adjust the rate projectile firing to compensate for any change in these conditions.

(17) Asteroids that would be arriving at the lunar or planetary surface will decelerate in a braking phase in preparation for landing. Landing sites will have been selected and have the automated landing systems set up in advance at each of them. The asteroid's attached thrust engines may receive telemetry data from the landing systems of one or more landing sites so that its own flight parameters can be confirmed before beginning a landing sequence. Once a landing site is selected (and preferably a suitable back-up landing site as well), the asteroid would use its own propulsion system to set up its initial trajectory for the landing. This could include, for example, an onboard ion propulsion system to steer the asteroid as needed. At the proper time, the two landing sites would turn on their micro-fusion landing cushions and confirm that they are working. Such a landing system could be employed for soft landing of small asteroids (up to 4 meters diameter and 100 metric tons mass) on the Moon, Mars, and the moons or Mars for subsequent asteroid mining. Initially only landing of very small asteroids (starting at about 10 metric tons) would be attempted, but as micro-fusion landing cushion technology and operational experience improves, it might eventually become possible to soft land somewhat larger asteroids (e.g., as much as 10 meters diameter and 1000 metric tons mass).