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Alien Technology On Earth
Space Mining Technology
Horta* Plasma
Rock Disintegration by Plasma Incursion
*The Horta was the creature of the Star Trek episode “The Devil in the Dark” that lived in
rock and was able to tunnel through it at will.
Counter
between the cooled surface and heated rock below it. A thermal gradient that is above the
crystalline phase change temperature of quartz will produce a mechanical expansion greater
than could simple thermal expansion. The internal pressure generated by either effect could
cause material to flake off the surface, or to shatter the rock.  

Microwaves were used for cutting and drilling into rock as shown in William C. Mauers book
Novel Drilling Techniques can be adapted for producing thermal inversions in rock.  I suggest
that in the vacuum of space, microwaves can heat artificially generated plasmas to use in rock
disintegration and ore extraction.

Ordinary matter will become plasma when heated to a high enough temperature. A plasma is a
gaseous or vaporized material that contains atoms which have been ionized. Ionized atoms have
free electrons (similar to metallic conductors) which contribute to the unusual properties of
plasma state of matter. The plasma's electrical properties permit electromagnetic fields to heat
the plasma. Ionization can be as low as 1 atom per billion to completely ionized. In a single
element plasma, the plasma density and the relative temperature can be a good indicator for
the degree of ionization. At high pressures and temperatures the electrical conductivity, (by
weight), of a plasma is much greater than for room temperature metallic conductors.

Plasma conductivity is the one of the properties that allow plasmas to be manipulated by
magnetic and electrostatic fields while enclosed by rock. Plasma can absorb electromagnetic
waves and be heated. Like metallic conductors, a plasma can partially absorb and/or reflect  
electromagnetic waves.   

Most rocks, unless they are pure metals or similar conductors, will allow the passage of
electromagnetic waves to some depth within them. The electromagnetic waves used could be
relatively long wavelengths like radio waves, or much shorter wavelengths like microwaves.
The temperature of a plasma can be maintained at some depth beneath the rock surface by
absorbing energy from impinging electromagnetic waves.

                                       Plasma Initiation
Any material object will become plasma if heated to a sufficient temperature. Heating the rock
surface with lasers, focused sunlight, or electric arcs can create a high temperature plasma.
The plasma created in the vacuum of space may persist for a longer period of time and be more
easily manipulated than at Earths atmosphere pressure.

               The Basic Properties of Confined Plasmas
Most plasma applications to not confine plasmas with physical walls. In conventional
applications it is considered wasteful and potentially destructive to have the plasma contact the
container walls. In fusion research and industrial sputtering processes the plasmas interaction
with their containers is minimized by design.

The utility of plasmas for mining can be divided along two lines, mechanical and chemical.
Mechanical effects can include cutting through or fracturing the rock. The chemical effects are
dependent on the elemental species of the plasma and the kind of chemical exchanges that will
occur when a plasma is in contact with rocks with different chemistries.

Horta Plasma is dependent upon contact with the rock surface to be effective. The technology
requirements should be less complex in confining a plasma than for sputtering or especially
fusion applications. The energy requirements for creating and maintaining confined plasmas
though are quite high. A plasma can be viewed as being similar to the arc created in terrestrial
welding. The larger the volume of the arc, the larger the energy requirements. A terrestrial arc
for welding is under atmospheric pressure and may actually be too dense and hot for our
application.

Electrons and heavy ions lose energy when they impact the walls confining them. The heavy
ions also can contact the walls and be chemically bound or physically captured beneath the
confining surface. Energy and the constituent elements of the plasma are being continually lost
to the surrounding walls.

All confined plasmas require energy input to maintain their equilibrium condition. A simplified
equilibrium condition exists when a gas is energized into a plasma that is confined by a material
that it cannot chemically interact with, it's heavy ions cannot sputter the surface, and the gas
cannot be captured within the surface of the confining material. These conditions can be met if
the density and temperature of the gas are below some limit. This could also represent the
minimum energy requirements for a confined plasma. This can also be considered the pilot light
condition for a confined plasma.

Increasing the energy of the previous example and either the energy deposited on the surface
of the container will cause it to melt, or the kinetic energy of the gas's heavy ions will sputter
atoms from the surface of the container. Some of the sputtered atoms from the container may
become ionized and join the plasma.

Further increasing the energy will cause the plasma density to increase and the heat flow to
the container walls to increase. Sputtering and melting of the container will increase. At some
point the atoms of the plasma that are from the container material will exceed the population of
the starter gas. Increasing the input energy above this point will produce mechanical and
thermal stresses that will be destructive to the container wall.

                     Vacuum Dispersion Unconstrained
In the vacuum of space, the plasmas constituent atoms will disperse at high velocities into
space. The plasma will need to be contained by walls or fields. The magnetic mirror cusp of a
solenoid may be able to partially contain plasma on the surface of a rock. In the vacuum of
space the plasma might only be contained because it does not have a direct kinetic path or line
of sight path to the surface. After multiple impacts on surfaces, the plasma components may be
entirely captured before they could escape to the surface vacuum.

To maintain plasma pressure a rock surface could be sealed by fusing sand into the cracks and
 fissures. Connected surface openings could be detected and located by their ionized emissions.
Within this sealed environment the plasma can undermine the rock, or begin processing the
material of the rock into more useful products. Enclosed within the rock, the pressures and
temperatures generated by the plasma could allow for efficient rock cutting or processing.

         Interaction Between Heated Plasma and Rock
The chemical interactions of plasmas can have some similarities to aqueous chemical
solutions. Some of properties that control plasma chemical reactions are an elements ionization
energy and the strength of the chemical bonds formed. The chemical bond strength is closely
associated with the temperature at which that chemical will vaporize into either smaller
molecules or into individual elements. A plasma can act as the solution for two chemically
different solids that are in a shared volume. An element with low ionization energy will tend to
remain in the plasma unless it is captured into a strong chemical bond. The  strong chemical
bond acts to raise the ionization energy and make it less likely that a heavy ion collision will
release it back into the plasma. The equilibrium begins to move towards higher ionization
energies. By manipulating the temperature of surfaces and the energy of the plasma a desired
chemical reactions can be selected for. Specific deposition of a desired chemical  may be
achieved by pulling heat away from a plasma reactive surface to maintain an optimum
temperature.

Eventually an equilibrium will be reached where the electromagnetic fields will no longer be
adding energy to the plasma and the number of sputtered atoms will match the number of
atoms being captured by the rock surface. In addition the ions velocity will decrease because
their acceleration is being interrupted by collisions with other atoms or electrons. This increase
in collisions is a direct result of  increasing plasma density.

A useful phenomena can occur when a solid derived plasma is allowed to cool and condense is
the creation of microparticles.  Boulos M. I.,Fauchais P., Pfender E., (1994) Thermal Plasmas.

 The size and nature of these particles is dependent on many factors. As certain components  
condense out of the plasma more quickly, they could form the seeds around which the rest of
the vapor will adhere. If these particles solidify before contacting the surface, they could form
spherical micro particles. These shape of these particles will partially restrict heat flow when
these particles fill a volume. Packed spherical particles have voids which will impede the flow of
heat. The voids act to thermally insulate them from the surrounding cooler rock. The thermal
insulation of their shape, along with their surface to volume ratio would allow the particles to be
returned to a plasma state with greater ease than solid rock.

Another possibility is that the micro particles could be returned to a plasma state by the
intense ultraviolet light created by nearby plasmas, without direct immersion in the plasma.
Another question, is for how long can these liquid particles maintain a temperature that will
allow them to be ionized or re-ignited by an electromagnetic source, is unknown. If these liquid
particles could maintain ignition temperature for a sufficient period of time, they could be
dropped into crevasses and then ignited before they reach the bottom.

                Direct Methods of Heating the Plasma
 A method to energize the plasma is by direct application of electrical power through
electrically heated filaments Moisan and Pelletier(1992) chapter 10. The electrons from the
electrically heated filaments can be directed against the rock by high voltage charges. Once
the plasma is created the high voltage will no longer be necessary. The circuit has similarities
to the ballast transformer used in fluorescent lighting.

Electrically heated filaments are also a primary component of electron tubes, which, can of
course function well in the vacuum of space. A less sophisticated industrial base is needed to
manufacture vacuum and gas filled tubes in space.  It might be be easier to bootstrap and
maintain industrial power components based on older tube technology. The free electrons from
the heated filaments could have eough energy to start the plasma.

 A laser or similar directed energy source could be fired into a rock fissure to take advantage
of surface fissures to act on deeper portions of the rock. The electrons emitted by the heated
filaments, along with the electromagnetic currents traveling through the filaments, could ionize
these particles and begin the plasma creation. Placing the electrodes/filaments of an electrical
generator at two fissures sharing a common plasma conduction path, would allow the direct
electrical heating of the plasma connecting the fissures.

 Creation of Free Electrons and Enhanced Conductivity Paths
Plasmas may be generated within entirely sealed off voids within the rock by the use of
ionizing radiation sources.  An ionizing radiation source such as an intense x-ray source could
be directed into the rock near a pocket or void. A microwave or RF beam could also be
directed to intersect the x-ray beam at some point near the pocket. The x-ray beam will create
free electrons in the rock with which the microwaves will interact to produce enough heating to
generate plasma in the pocket.

In the pocket near the intersection of these two energy sources, particles may be ionized and
ejected into the pocket. This will seed the plasma in the pocket and the microwave source will
begin heating the plasma and increasing its density. The plasma in the pocket will need to be
established very quickly to prevent heating and thereby increasing the conductivity and
microwave absorption of nearby rock. With the plasma established in this pocket or void in the
rock other possibilities will then exist.

Radioactive materials with short half-lives could be injected or physically placed within
fissures to create free electron sources within the rock. The interaction of the microwave beam
with these radioactive sources would be very similar to the x-ray example. Easily ionized
material could be mechanically transported through the surface fissures of the rock and then be
ionized, at some depth, beneath the rock face. This could allow plasma generation deep within
the rock, without the problems of maintaining and manipulating the plasma from the surface of
the rock.

             In Situ Removal of Desired Components
There exists the possibility that the plasma could be used to selectively remove components,
or elements from the rock. This would mean that the slag, waste products, and overburden
would never need be handled or removed. The rock itself would become the processing
chamber. The plasma vapor generated in the rock could be vented or piped to a sophisticated
processing unit. The processing unit could condense and/or separate the desired components.
The presence of oxygen and nitrogen in the Earth's atmosphere makes this technique difficult
on the Earth's surface. Oxides and Nitrogen compounds tend to require higher temperatures to
vaporize than native metals and elements.

The position of the plasma within the rock could accurately be determined with a highly
collimated microwave system and a means of monitoring microwave reflections from the
plasma. With this position sensitivity, a very versatile method of cutting could become possible.
By having the plasma follow existing fissures it could be moved at a relatively high speed
through the rock. This could be used to sample areas where direct line-of-sight laser
spectroscopy would not work. This could also be helpful in tracking ore veins or broken or
discontinuous ore bodies. Once the end points of an ore vein are mapped the plasma could
vaporize a path following the vein.

If the material that the plasma is traveling through requires a higher temperature for ionization
than those atoms to recruit atoms from the surrounding rock to make up for losses. Another
factor that is dependent on the elements involved, would be pressure, and by default the
temperature, that the plasma would have to be maintained. The balance between temperature
and pressure would be fundamental to maintaining the integrity of the plasma within changing
rock chemistry.

The vacuum of space may make it economical to modify the existing techniques used for
isotope separation. Techniques used for isotope separation such as diffusion and selective
laser stimulation may be modified for use in separating and purifying individual elements.
Plasma processes consume high amounts of electrical energy making high purity silicon high
priority for use in solar cells.

Some Limitations on Plasma Manipulation by Electromagnetic Waves
Plasma may be created by several means, but to move and maintain the plasma without direct
contact will usually require electromagnetic fields. Plasma has a property referred to as Debye
Shielding, this shielding limits the depth that an electromagnetic field can penetrate into a
volume of plasma. For small cracks or fissures the affect of Debye Shielding should not be a
problem. The plasma density would need to be high to present any problems for heating a small
volume.

Plasma would work the most efficiently in a small volume where the energy requirements for
heating the plasma would not be excessive. Once a deep pocket of plasma has been created the
microwave generator could apply maximum power to heat the plasma in the pocket. The
plasma could then create a thermal inversion to fracture the rock between the plasma pocket
and the rock surface.

                       Apologies and Acknowledgments
I must apologize to anyone that I have not cited properly. I did very little research in writing
the original of this paper, and my haste was not meant to slight. If you feel that your work was
relevant and should have been cited, please contact me and I shall try to rectify it. The original
paper was written for the Space Resources Round Table of 2002. I was unable to attend to give
it. Special thanks to Dr. Michael Duke for letting me give a paper titled The Ants of Toutatis'
in 2001 and Dr. Leslie Gertsch for telling me about the books of William C. Maurer.

Mauer, W.C. (1968). Novel Drilling Techniques

Lieberman M.A., Lichtenberg A.J.(1994). Principles of Plasma Discharges and Materials
Processing. A Wiley-Interscience Publication.

Moisan, M. Pelletier J. editors (1992). Microwave Excited Plasmas, Plasma Technology,
Elsevier Publishing

Boulos M. I.,Fauchais P., Pfender E., (1994) Thermal Plasmas Fundamentals and Applications
Volume 1 Plenum Press.