9.  Nanotechnology and Aerospace Supermaterials

Nanotechnology is the new science of assembling exotic new materials at the molecular and atomic level. These materials, according to computer modeling, could be made much stronger, harder, and more heat resistant than anything we can manufacture today. The materials could have active properties, like living tissue, and also be highly integrated. All electronics could be built right in.

Note resemblance of the described physical properties of these nanomaterials to physical properties of debris described by many Roswell witnesses, including extreme strength and very light weight.  In particular, pay special attention to descriptions of "carbon nanotubules" or nanotubes, a supermaterial that exists in laboratories today, and could seemingly reproduce the properties of the strange "memory foil" described by many witnesses.

When Roswell witnesses first started describing such properties in 1979, they were well beyond our capabilities at the time, much less in 1947.  In the last dozen years, however, materials technology aided by computer modeling, tells us that superstrong, very hard, very lightweight, and highly heat resistant materials are indeed possible.  They would make ideal materials from which to construct a spacecraft or aircraft, among many other possible applications.

The following is a tiny sampling of the vast literature on this futuristic materials technology.


Properties of Carbon Nanotubules

Scientific American article, January 2000

Superstrong Materials:  Embedded into a composite, nanotubes have enormous resilience and tensile strength and could be used to make cars that bounce in a wreck or buildings that sway rather than cracking in an earthquake.

           Carbon Nanotubes                Roswell Foil Debris Descriptions
-------------------------------------------------------------------------------
Tensile Strength:  45 billion Pascals vs.   Extremely tough. Couldn't be
2 billion Pascals for the best steel              torn; couldn't be cut with knife
alloys before they break

Density & Lightness:  1.33 to 1.40 grams    Very light in weight; like a feather;
per cubic centimeter vs. 2.7 g/cm^3 for     almost like it wasn't there at all.
aluminum (& 8.0 g/cm^3 for steel)                                  

Resilience/Memory:  Can be bent at large    Highly resilient.  Could be crumpled
angles and restraightened without damage.   and would unfold to original smooth-
Carbon fibers and normal metals fracture    ness.  Wouldn't wrinkle or crease.
at grain boundaries (causing wrinkles,      Wouldn't hold a dent.  Metallic
creases, dents, and breakage).              but with plastic properties.

Heat Transmission:  Predicted to be as      Unaffected by ordinary flame,
high as 6000 watts per meter per Kelvin     acetylene torch, or hot coals.
at room temperature vs. 3320 W/m/K for      Barely got warm when heated with
nearly pure diamond or 430 W/m/K for        a torch and cooled within seconds.
silver. (Nanotubes have highest known       (Acetylene torches get up to 3480
heat transmission)                          deg. C or 6300 deg. F)

Temperature Stability:  Stable up to        Unaffected by ordinary flame,
2800 deg. Celsius (5000 deg. Fahrenheit)    acetylene torch, or hot coals.
in a vacuum; 750 deg C in air (1400 F);    

Size:  0.6 to 1.8 nanometers in diameter    Some descriptions of foil being
(Threads of nanotube fibers could be        fabric-like or porous (could be
woven into a cloth or fabric.)              blown through).

Electrical Properties:  Can be varied       Material mostly described as dull
from semiconducting to highly conducting;   gray or silver-gray in color like
semiconductor material could be dull in     lead foil or unpolished gun-metal
color while highly conducting material      or aluminum.  Some descriptions of
could appear shiny and metallic.            shiny metallic appearance.


Discover Magazine, January 1999, page 38

Technology 1998 --Tomorrow's Tubes
by Jeffrey Winter

Ever since they were discovered in 1991, carbon nanotubes --cylindrical molecules of graphite that look a bit like rolled-up chicken wire -- have been touted as the material of the future. Pound for pound, carbon nanotubes are about a hundred times stronger than steel and transport heat better than any other known material. But while bridges suspended from whisker-thin nanotube cables are probably some decades away, a newly discovered realm of application for the strange molecules -- electronics -- may be at hand.

When a carbon atom links up with neighboring carbons to make a sheet of graphite, some of the atoms' electrons are left unbound, free to roam around and conduct electricity throughout the sheet. Because carbon nanotubes are simply graphite tubes, it was not surprising that they could also conduct electricity.

But in June, Walter de Heer and his colleagues at Georgia Tech found that nanotubes can do something no ordinary wires can do-- conduct electricity with almost no resistance at room temperature.

While nanotubes are not superconductors (the current in a superconductor, unlike that in nanotubes, continues to flow even when the power source is shut off), their highly regular molecular structure allows electrons to flow freely without losing energy in collisions with stray atoms. Resistance-free nanotube wires could greatly reduce the size of electronic components.

Other research groups found equally surprising properties. In January, teams at Harvard and at Delft University of Technology in the Netherlands demonstrated that nanotubes made of a single layer of carbon could conduct electricity either like a metal or like a semiconductor, depending on the alignment of carbon atoms in the nanotube. By May, Cees Dekker of the Delft team had managed to rig up the world's first nanotube transistor; it was less than a tenth of the size of a conventional semiconductor transistor.

Physicists are already talking about stringing together nanotubes to create carbon-based molecular electronic devices to replace the ubiquitous silicon- based computer chips.

Says Walter de Heer: "There's a new era of electronics awaiting for us."



2002 NASA Web page
(http://science.nasa.gov/headlines/y2002/16sep_rightstuff.htm?list100309)

The Right Stuff for Super Spaceships
Tomorrow's spacecraft will be built using advanced materials with mind-boggling properties.

Revolutions in technology--like the Industrial Revolution that replaced horses with cars--can make what seems impossible today commonplace tomorrow.

Such a revolution is happening right now. Three of the fastest-growing sciences of our day--biotech, nanotech, and information technology--are converging to give scientists unprecedented control of matter on the molecular scale. Emerging from this intellectual gold-rush is a new class of materials with astounding properties that sound more at home in a science fiction novel than on the laboratory workbench.

Imagine, for example, a substance with 100 times the strength of steel, yet only 1/6 the weight; materials that instantly heal themselves when punctured; surfaces that can "feel" the forces pressing on them; wires and electronics as tiny as molecules; structural materials that also generate and store electricity; and liquids that can instantly switch to solid and back again at will. All of these materials exist today ... and more are on the way.

With such mind-boggling materials at hand, building the better spacecraft starts to look not so far fetched after all.

... Composite materials, like those used in carbon-fiber tennis rackets and golf clubs, have already done much to help bring weight down in aerospace designs without compromising strength. But a new form of carbon called a "carbon nanotube" holds the promise of a dramatic improvement over composites: The best composites have 3 or 4 times the strength of steel by weight--for nanotubes, it's 600 times!

"This phenomenal strength comes from the molecular structure of nanotubes," explains Dennis Bushnell, a chief scientist at Langley Research Center (LaRC), NASA's Center of Excellence for Structures and Materials. They look a bit like chicken-wire rolled into a cylinder with carbon atoms sitting at each of the hexagons' corners. Typically nanotubes are about 1.2 to 1.4 nanometers across (a nanometer is one-billionth of a meter), which is only about 10 times the radius of the carbon atoms themselves.

Nanotubes were only discovered in 1991, but already the intense interest in the scientific community has advanced our ability to create and use nanotubes tremendously. Only 2 to 3 years ago, the longest nanotubes that had been made were about 1000 nanometers long (1 micron). Today, scientists are able to grow tubes as long as 200 million nanometers (20 cm). Bushnell notes that there are at least 56 labs around the world working to mass produce these tiny tubes.

"Great strides are being made, so making bulk materials using nanotubes will probably happen," Bushnell says. "What we don't know is how much of this 600 times the strength of steel by weight will be manifest in a bulk material. Still, nanotubes are our best bet."

Beyond merely being strong, nanotubes will likely be important for another part of the spacecraft weight-loss plan: materials that can serve more than just one function.

"We used to build structures that were just dumb, dead-weight holders for active parts, such as sensors, processors, and instruments," Marzwell explains. "Now we don't need that. The holder can be an integral, active part of the system."

Imagine that the body of a spacecraft could also store power, removing the need for heavy batteries. Or that surfaces could bend themselves, doing away with separate actuators. Or that circuitry could be embedded directly into the body of the spacecraft. When materials can be designed on the molecular scale such holistic structures become possible...

Other

July 2001 -- Army R&D developing super-lightweight armor

In the excerpt below, notice how the article talks about creating body armor that theoretically could be 2 or even 3 orders of magnitude lighter in weight than present armor. Something as thin as a piece of paper could stop a .45 caliber bullet. Furthermore, it could have electronics and power supply integrated right into the armor.  Though not stated, the proposed armor is probably based around carbon nanotubules with their enormous strength, lightness, plus the ability to vary their electrical properties and theoretically create integrated electronics.


http://www.rense.com/general11/nan.htm

Army Exploring Nanotechnology And Robotics
by Kelly Hearns, UPI Technology Writer, 7/1/01

Q. How much is the Army going to use nanotechnology, say, over the next decade?

A. The university laboratories have been making pretty good progress in nanoscience. And technology follows science. Until you understand the science you can't move into technology efforts. You have to have equipment to allow for the fabrication of materials and devices on the nanoscale. So we have to have a good characterization before we are ready to move into the fabrication and application state. We'll see progress in the field of materials, new materials and our new Institute For Soldier Nanotechnology will focus on soldiers' uniforms.

Our first step is to develop a uniform, using nanoscale materials to integrate electronics, computer devices and power supply. And for ballistic protection. For example, today if you want to stop a .45 caliber bullet you need about 10 to 20 pounds per square foot. Where we are headed with nanoscience and technology is the ability to stop a bullet with as much as two or three orders of magnitude less in pounds, something as thin and light as a piece of paper stopping a .45 caliber bullet. That's the potential. If we could drop this under one pound per square foot we've made dramatic progress. So, our mark on the wall is more than a factor of 10 drop in that ballistic protection. Also, we hope to get technologies into the marketplace so volumes will grow and prices will drop.


1997 NASA TECHNICAL REPORT
(Originally at   http://www.nas.nasa.gov/nanotechnology)

The following portions of a technical report from NASA described a paper by Jie Han, Al Globus, Richard Jaffe and Glenn Deardorff of NASA's Ames Research Center, Mountain View, CA.  In this paper, the authors describe the physical properties of materials which their computer models indicate could be assembled at the molecular level through the use of molecular "nanomachines."

"We would like to write computer programs that would enable assembler/ replicators to make aerospace materials, parts and machines in atomic detail," he [Globus] said.  "Such materials should have tremendous strength and thermal properties."
   
A long range goal, according to Globus, is to make materials that have radically superior strength-to-weight ratio.  Diamond, for example, has 69 times the strength-to-weight ratio of titanium.  A second goal is to make "active" or "smart" materials.
   
"There is absolutely no question that active materials can be made," Globus explained.  "Look at your skin.  It repairs itself.  It sweats to cool itself.  It stretches as it grows.  It's an active material," he said.


NSS (NATIONAL SPACE SOCIETY) POSITION PAPER
ON SPACE AND NANOTECHNOLOGY
[From former Website http://www.public.iastate.edu/~bhein/txt/mmsg.txt]

[Nanotech aerospace] products might include bulk structures such as spacecraft components made of a diamond-titanium composite, or other "wonder" materials.  The theoretical strength-to-density ratio of matter is about 75 times that currently achieved by aerospace aluminum alloys, partially because current manufacturing capability allows macro-molecular defects that weaken the material.

A dense network of distributed embedded sensors throughout a manned or unmanned spacecraft could continuously monitor (and affect, if they could be operated as actuators) mechanical stresses, temperature gradients, incident radiation, and other parameters to ensure mission safety and optimize system control.  In an advanced spacecraft, the outer skin would not only keep out the cold and the vacuum, but it might also function as a multi-sensor camera and antenna.

Tiny computers, sensors and actuators, trivially cheap on a per-unit basis, may allow things like smart walls to automatically repair micrometeorite damage.


Superalloy Announced  (New!  Added April 29, 2003)

© Nature News Service / Macmillan Magazines Ltd 2003

New alloys bend the rules
Metal mixes are supple, stretchy, strong and heat stable.
18 April 2003
PHILIP BALL

© Corbis
A new class of metal alloys has a remarkable combination of unusual and useful properties: all its members are strong, heat-stable, supple and elastic1.

The materials are compounds of titanium, zirconium, vanadium, niobium and tantalum - elements clustered together in the middle of the periodic table, in a larger group known as the transition metals. A small amount of oxygen provides an essential seasoning in the mix.

Most metals would be permanently deformed if stretched to up to 2.5 times their original length. But the new alloys spring back again - earning them the title 'super-elastic'. When pulled harder, they extend by a further 20% before they snap. This degree of stretchiness is most unusual for a metal, and is dubbed superplasticity.

The mixtures' super-elasticity means that they don't dent easily; their superplasticity means that they can be moulded without the need for heat. But it doesn't stop there, say developers Takashi Saito, of Toyota Central Research and Development Laboratories in Nagakute, Japan, and his colleagues.

When warmed, the alloys barely expand. This rare, 'invar' behaviour is characteristic of some nickel-steel mixes that were discovered in the 1890s and are used in parts of delicate mechanisms such as wristwatches and scientific measuring instruments. This refusal to expand when warmed means that the devices are accurate across a range of temperatures.

The new compounds also show 'elinvar' behaviour - their stiffness remains constant when they are heated. This effect holds over an amazingly wide temperature range - from as low as -194 °C to over 200 °C.

To cap it all, the alloys are very strong. Their tensile strength - the amount of pulling that they can stand - is about twice that of steel. And they can be bent and straightened repeatedly without becoming brittle; they don't suffer from 'work hardening', in other words.
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References
Saito, T. et al. Multifunctional alloys obtained via a dislocation-free plastic deformation mechanism. Science, 300, 464 - 467, (2003). |Homepage|