See Kurzweil (1999) re his proposal for liquid DNA
On Fri, 31 Mar 2000, Charles Daneso wrote:
> -> IUFO Mailing List
> In Terminator II. The android can be in liquid form. It can change shape.
> Is it a product of nanotechnology? Do you think it can become possible
> At 03:02 PM 3/31/00 -0800, you wrote:
> >-> IUFO Mailing List
> >---------- Forwarded message ----------
> >Date: Thu, 30 Mar 2000 23:54:59 -0800 (PST)
> >From: Eugene Leitl <eugene.leitl@...-muenchen.de>
> >Reply-To: firstname.lastname@example.org
> >To: email@example.com, firstname.lastname@example.org
> >Subject: [transhumantech] NSG-D/ NASA applications of molecular
> > nanotechnology
> >Found by Fred Hapgood <hapgood at pobox dot com>
> >NASA applications of molecular nanotechnology
> >Al Globus, David Bailey, Jie Han, Richard Jaffe, Creon Levit, Ralph
> >Merkle, and Deepak Srivastava
> >Published in The Journal of the British Interplanetary Society, volume
> >51, pp. 145-152, 1998.
> >Laboratories throughout the world are rapidly gaining atomically precise
> >control over matter. As this control extends to an ever wider variety of
> >materials, processes and devices, opportunities for applications relevant
> >to NASA's missions will be created. This document surveys a number
> >of future molecular nanotechnology capabilities of aerospace interest.
> >Computer applications, launch vehicle improvements, and active
> >materials appear to be of particular interest. We also list a number of
> >applications for each of NASA's enterprises. If advanced molecular
> >nanotechnology can be developed, almost all of NASA's endeavors will
> >be radically improved. In particular, a sufficiently advanced molecular
> >nanotechnology can arguably bring large scale space colonization within
> >our grasp.
> >This document describes potential aerospace applications of molecular
> >nanotechnology, defined as the thorough three-dimensional structural
> >control of materials, processes and devices at the atomic scale. The
> >inspiration for molecular nanotechnology comes from Richard P.
> >Feynman's 1959 visionary talk at Caltech in which he said, "The
> >problems of chemistry and biology can be greatly helped if our ability to
> >see what we are doing, and to do things on an atomic level, is ultimately
> >developed---a development which I think cannot be avoided." Indeed,
> >scanning probe microscopes (SPMs) have already given us this ability in
> >limited domains. See the IBM Almaden STM Gallery for some
> >beautiful examples. Synthetic chemistry, biotechnology, "laser
> >tweezers" and other developments are also bringing atomic precision to
> >our endeavors.
> >[Drexler 92a], an expanded version of Drexler's MIT Ph.D. thesis,
> >examines one vision of molecular nanotechnology in considerable
> >technical detail. [Drexler 92a] proposes the development of
> >programmable molecular assembler/replicators. These are atomically
> >precise machines that can make and break chemical bonds using
> >mechanosynthesis to produce a wide variety of products under software
> >control, including copies of themselves. Interestingly, living cells exhibit
> >many properties of assembler/replicators. Cells make a wide variety of
> >products, including copies of themselves, and can be programmed with
> >DNA. Replication is one approach to building large systems, such as
> >human rated launch vehicles, from molecular machines manipulating
> >matter one or a few atoms at a time. Note that biological replication is
> >responsible for systems as large as redwood trees and whales.
> >Another approach to nanotechnology is supramolecular self-assembly,
> >where molecular systems are designed to attract each other in a
> >particular orientation to form larger systems. Hollow spheres large
> >enough to be visible in a standard light microscope have been created
> >this way using self-assembling lipids. There are many other examples
> >and this field is rapidly advancing. Biological systems can do most of
> >what molecular nanotechnology strives to accomplish -- atomically
> >precise products, active materials, reproduction, etc. However, biological
> >systems are extremely complex and molecular nanotechnology seeks
> >simpler systems to understand, control and manufacture. Also,
> >biological systems usually work at fairly mild temperature and pressure
> >conditions in solution -- conditions that are not found in most
> >aerospace environments.
> >Today, extremely precise atomic and molecular manipulation is
> >common in many laboratories around the world and our abilities are
> >rapidly approaching Feynman's dream. The implications for aerospace
> >development are profound and ubiquitous. A number of applications are
> >mentioned here and a few are described in some detail with references.
> >From this sample of applications it should be clear that although
> >molecular nanotechnology is a long term, high risk project, the payoff is
> >potentially enormous -- vastly superior computers, aerospace
> >transportation, sensors and other technologies; technologies that may
> >enable large scale space exploration and colonization.
> >This document is organized into two sections. In the first, we examine
> >three technologies -- computers, aerospace transportation, and active
> >materials -- useful to nearly all NASA missions. In the second, we
> >investigate some potential molecular nanotechnology payoffs for each
> >area identified in NASA's strategic plan. Some of these applications are
> >under investigation by nanotechnology researchers at NASA Ames.
> >Some of the applications described below have relatively near-term
> >potential and working prototypes may be realized within three to five
> >years. This is certainly not true in other cases. Indeed, many of the
> >possible applications of nanotechnology that we describe here are, at the
> >present time, rather speculative and futuristic. However, each of these
> >ideas have been examined at least cursorily by competent scientists, and
> >as far as we know all of them are within the bounds of known physical
> >laws. We are not suggesting that their achievement will be easy, cheap
> >or near-term. Some may take decades to realize; some other ideas may
> >be scrapped in the coming years as insuperable barriers are identified.
> >But we feel that they are worth mentioning here as illustrations of the
> >potential future impact of nanotechnology.
> >Computer Technology
> >The applicability of manufacturing at an ever smaller scale is nowhere
> >more self-evident than in computer technology. Indeed, Moore's law
> >[Moore 75] (an observation not a physical law) says that computer chip
> >feature size decreases exponentially with time, a trend that predicts
> >atomically precise computers by about 2010-2015. This capability is
> >being approached from many directions. Here we will concentrate on
> >those under development by NASA Ames and her partners. For a
> >review of many other approaches see [Goldhaber-Gordon 97].
> >Carbon Nanotube SPM Tips
> >Carbon nanotubes [Iijima 91] can be viewed as rolled up sheets of
> >graphite from 0.7 to many nanometers in diameter. The smaller tubes
> >are single molecules. [Dai 96] placed carbon nanotubes on an SPM tip
> >thus extending our ability to manipulate a single molecule with
> >sub-angstrom accuracy. Not only are the tips atomically precise, but
> >they should have approximately the same chemistry as C60, and thus be
> >functionalizable with a wide variety of molecular fragments [Taylor 93].
> >Functionalizing carbon nanotube tips will allow mechanical
> >manipulation of many molecular systems on various surfaces with
> >sub-angstrom accuracy.
> >One particularly intriguing possibility along this line is to utilize a
> >carbon nanotube SPM tip to engrave patterns on a silicon surface. It
> >should be possible to create features a few nanometers across. These
> >would be perhaps 100 times finer than the current state of the art in
> >commercial semiconductor photolithography. Further, in contrast to
> >approaches such as electron microscope lithography for which the speed
> >of operation now appears to be an insuperable obstacle for industrial
> >production, nanotube SPM-based lithography can be accelerated by
> >utilizing an array with thousands of SPM tips simultaneously engraving
> >different parts of a silicon surface. Also, nanotube SPM lithography
> >could provide a practical means to explore various futuristic electronic
> >device technology ideas, such as quantum cellular automata, which
> >require exceedingly small feature sizes. Needless to say, if these ideas
> >pan out, they could literally revolutionize computer device technology,
> >paving the way for systems that are many times more powerful and
> >more compact than any available today.
> >For the near term, it should be noted that the semiconductor industry is
> >a major market for SPM products. These are used to examine
> >production equipment. High performance carbon nanotube tips should
> >be of substantial value. NASA Ames is collaborating with Dr. Dai, now
> >at Stanford, to develop these tips.
> >Data Storage on Molecular Tape
> >It is possible to store data on long chain molecules (for example, DNA)
> >and it may be possible to read these data with carbon nanotube tipped
> >SPMs. Existing DNA synthesis techniques can be used to write data. If
> >the different DNA base pairs can be distinguished with a carbon
> >nanotube tipped SPM, then the data can be read non-destructively
> >(current techniques allow a destructive read). However, the difference
> >between base pairs is not great. If the base pairs cannot be distinguished,
> >techniques for attaching modified enzymes to specific base pair
> >sequences [Smith 97] could be used. Certain enzymes (DNA
> >(cytosine-5) methyltransferases) attach themselves onto a specific
> >sequence of base pairs with a covalent bond. The enzyme then performs
> >its operation and breaks the bond. [Smith 97] modified the enzyme such
> >that the initial covalent bond was formed but the subsequent operation
> >was disrupted. The result is that DNA synthesized with the target base
> >pair sequences at the desired location can force precise placement of the
> >enzymes. The presence of an enzyme could represent 1 and its absence
> >0. Enzymes are sufficiently large that distinguishing their presence
> >should be straightforward. If the DNA/enzyme approach proves
> >impossible, a wide variety of other polymer systems could be examined.
> >Data Storage on Diamond
> >[Bauschlicher 97a] computationally studied storing data in a pattern of
> >fluorine and hydrogen atoms on the (111) diamond surface (see figure).
> >If write-once data could be stored this way, 1015 bytes/cm2 is
> >theoretically possible. By comparison, the new DVD write-once disks
> >now coming on the market hold about 108 bytes/cm2. [Bauschlicher
> >97a] compared the interaction of different probe molecules with a one
> >dimensional model of the diamond surface. This study found some
> >molecules whose interaction energies with H and F are sufficiently
> >different that the force differential should be detectable by an SPM.
> >These studies were extended to include a two dimensional model of the
> >diamond surface and two other systems besides F/H [Bauschlicher 97b].
> >Other surfaces, such as Si, and other probes, such as those including
> >transition metal atoms, have also been investigated [Bauschlicher 97c].
> >Among the better probes was C5H5N (pyridine). Quantum calculations
> >suggest that pyridine is stable when attached to C60 in the orientation
> >necessary for sensing the difference between hydrogen and fluorine.
> >Half of C60 can form the end cap of a (9,0) or (5,5) carbon nanotube,
> >and carbon nanotubes have been attached to an SPM tip [Dai 96]. Thus,
> >it might be possible using today's technology to build a system to read
> >the diamond memory surface.
> >[Avouris 96] has shown that individual hydrogen atoms can be removed
> >from a silicon surface. If this could be accomplished in a gas that
> >donates fluorine to vacancies on a diamond surface, the data storage
> >system could be built. [Thummel 97] computationally investigated
> >methods for adding a fluorine at the radical sites where a hydrogen atom
> >had been removed from a diamond surface.
> >Carbon Nanotube Electronic Components
> >As mentioned before, carbon nanotubes can be described as rolled up
> >sheets of graphite. Different tubes can have different helical windings
> >depending on how the graphite sheet is connected to itself. Theory
> >[Dresselhaus 95, pp. 802-814] suggests that single-walled carbon
> >nanotubes can have metallic or semiconductor properties depending on
> >the helical winding of the tube. [Chico 96], [Han 97b], [Menon 97a],
> >[Menon 97b], and others have computationally examined the properties
> >of some of hypothetical devices that might be made by connecting tubes
> >with different electrical properties. Such devices are only few
> >nanometers across -- 100 times smaller than current computer chip
> >features. For a number of references in fullerene nanotechnology see
> >[Globus 97].
> >Molecular Electronic Components
> >Several authors, including [Tour 96], have described methods to
> >produce conjugated macromolecules of precise length and composition.
> >This technique was used to produce molecular electronic devices in
> >mole quantities [Wu 96]. The resultant single molecular wires were
> >tested experimentally and found to be conducting [Bumm 96]. The
> >three and four terminal devices have been examined computationally
> >and look promising [Tour 97]. The features of these components are
> >approximately 3 angstroms wide, about 750 times smaller than current
> >silicon technology can produce.
> >Helical Logic
> >From [Merkle 96]:
> > Helical logic is a theoretical proposal for a future computing
> > technology using the presence or absence of individual
> > electrons (or holes) to encode 1s and 0s. The electrons are
> > constrained to move along helical paths, driven by a rotating
> > electric field in which the entire circuit is immersed. The
> > electric field remains roughly orthogonal to the major axis of
> > the helix and confines each charge carrier to a fraction of a
> > turn of a single helical loop, moving it like water in an
> > Archimedean screw. Each loop could in principle hold an
> > independent carrier, permitting high information density.
> > One computationally universal logic operation involves two
> > helices, one of which splits into two "descendant" helices. At
> > the point of divergence, differences in the electrostatic
> > potential resulting from the presence or absence of a carrier
> > in the adjacent helix controls the direction taken by a carrier
> > in the splitting helix. The reverse of this sequence can be
> > used to merge two initially distinct helical paths into a single
> > outgoing helical path without forcing a dissipative transition.
> > Because these operations are both logically and
> > thermodynamically reversible, energy dissipation can be
> > reduced to extremely low levels. ... It is important to note that
> > this proposal permits a single electron to switch another
> > single electron, and does not require that many electrons be
> > used to switch one electron. The energy dissipated per logic
> > operation can likely be reduced to less than 10-27 joules at a
> > temperature of 1 Kelvin and a speed of 10 gigahertz, though
> > further analysis is required to confirm this. Irreversible
> > operations, when required, can be easily implemented and
> > should have a dissipation approaching the fundamental limit
> > of ln 2 x kT.
> >Rod Logic
> >One study not conducted by Ames or partners is particularly worth
> >mentioning since it places a loose lower bound on the computational
> >capabilities of molecular nanotechnology. [Drexler 92a] designed a
> >number of computer components using small diamondoid rods with
> >knobs that allow or prevent movement to accomplish computation.
> >While this tiny mechanical Babbage Machine is probably not an optimal
> >computational engine, its calculated performance for a desktop
> >computer is 1018 MIPS -- about a million times more powerful than the
> >largest supercomputer that exists today (Fall 1997).
> >Note that with very fast computation energy use and heat dissipation
> >become a severe problem. One approach to addressing this issue is
> >reversible logic.
> >Aerospace Transportation
> >Launch Vehicles
> >[Drexler 92a] proposed a nanotechnology based on diamond and
> >investigated its potential properties. In particular, he examined
> >applications for materials with a strength similar to that of diamond (69
> >times strength/mass of titanium). This would require a very mature
> >nanotechnology constructing systems by placing atoms on diamond
> >surfaces one or a few at a time in parallel. Assuming diamondoid
> >materials, [McKendree 95] predicted the performance of several
> >existing single-stage-to-orbit (SSTO) vehicle designs. The predicted
> >payload to dry mass ratio for these vehicles using titanium as a
> >structural material varied from < 0 (the vehicle won't work) to 36%, i.e.,
> >the vehicle weighs substantially more than the payload. With
> >hypothetical diamondoid materials the ratios varied from 243% to
> >653%, i.e., the payload weighs far more than the vehicle. Using a very
> >simple cost model ($1000 per vehicle kilogram) sometimes used in the
> >aerospace industry, he estimated the cost per kilogram launched to
> >low-Earth-orbit for diamondoid structured vehicles should be
> >$153-412. This would meet NASA's 2020 launch to orbit cost goals.
> >Estimated costs for titanium structured vehicles varied from
> >$16,000-59,000/kg. Although this cost model is probably adequate for
> >comparison, the absolute costs are suspect.
> >[Drexler 92b] used a more speculative methodology to estimate that a
> >four passenger SSTO weighing three tons including fuel could be built
> >using a mature nanotechnology. Using McKendree's cost model, such a
> >vehicle would cost about $60,000 to purchase -- the cost of today's
> >high-end luxury automobiles.
> >These studies assumed a fairly advanced nanotechnology capable of
> >building diamondoid materials. In the nearer term, it may be possible to
> >develop excellent structural materials using carbon nanotubes. Carbon
> >nanotubes have a Young's modulus of approximately one terapascal --
> >comparable to diamond. Studies of carbon nanotube strength include
> >[Treacy 96], [Yacobson 96], and [Srivastava 97a].
> >Space Elevator
> >[Issacs 66] and [Pearson 75] proposed a space elevator -- a cable
> >extending from the Earth's surface into space with a center of mass at
> >geosynchronous altitude. If such a system could be built, it should be
> >mechanically stable and vehicles could ascend and descend along the
> >cable at almost any reasonable speed using electric power (actually
> >generating power on the way down). The first incredibly difficult
> >problem with building a space elevator is strength of materials.
> >Maximum stress is at geosynchronous altitude so the cable must be
> >thickest there and taper exponentially as it approaches Earth. Any
> >potential material may be characterized by the taper factor -- the ratio
> >between the cable's radius at geosynchronous altitude and at the Earth's
> >surface. For steel the taper factor is tens of thousands -- clearly
> >impossible. For diamond, the taper factor is 21.9 [McKendree 95]
> >including a safety factor. Diamond is, however, brittle. Carbon
> >nanotubes have a strength in tension similar to diamond, but bundles of
> >these nanometer-scale radius tubes shouldn't propagate cracks nearly as
> >well as the diamond tetrahedral lattice. Thus, if the considerable
> >problems of developing a molecular nanotechnology capable of making
> >nearly perfect carbon nanotube systems approximately 70,000
> >kilometers long can be overcome, the first serious problem of a
> >transportation system capable of truly large scale transfers of mass to
> >orbit can be solved. The next immense problem with space elevators is
> >safety -- how to avoid dropping thousands of kilometers of cable on
> >Earth if the cable breaks. Active materials may help by monitoring and
> >repairing small flaws in the cable and/or detecting a major failure and
> >disassembling the cable into small elements.
> >Interplanetary transportation
> >[Drexler 92b] calculates that lightsails made of 20 nm aluminum in
> >tension should achieve an outward acceleration of ~14 km/s per day at
> >Earth orbit with no payload and minimal structural overhead. For
> >comparison, the delta V from low Earth to geosynchronous orbit is 3.8
> >km/s. Lightsails generate thrust by reflecting sunlight. Tension is
> >achieved by rotating the sail. The direction of thrust is normal to the
> >sail and away from the Sun. By directing thrust along or against the
> >velocity vector, orbits can be lowered or raised. This form of
> >transportation requires no reaction mass and generates thrust
> >continuously, although the instantaneous acceleration is small so sails
> >cannot operate in an atmosphere and must be large for even moderate
> >Active Materials
> >Today, the smallest feature size in production systems is about 250
> >nanometers -- the smallest feature size in computer chips. Since atoms
> >are an angstrom or so across and carbon nanotubes have a diameter as
> >small as 0.7 nanometers, atomically precise molecular machines can be
> >smaller than current MEMS devices by two to three orders of
> >magnitude in each dimension, or six to nine orders of magnitude
> >smaller in volume (and mass). For example, the size of the kinesin
> >motor, which transports material in cells, is 12 nm. [Han 97a]
> >computationally demonstrated that molecular gears fashioned from
> >single-walled carbon nanotubes with benzyne teeth should operate well
> >at 50-100 gigahertz. These gears are about two nanometers across. [Han
> >97c] computationally demonstrated cooling the gears with an inert
> >atmosphere. [Srivastava 97c] simulated powering the gears using
> >alternating electric fields generated by a single simulated laser. In this
> >case, charges were added to opposite sides of the tube to form a dipole.
> >For an examination of the state-of-the-art in small machines see the
> >1997 Conference on Biomolecular Motors and Nanomachines.
> >To make active materials, a material might be filled with nano-scale
> >sensors, computers, and actuators so the material can probe its
> >environment, compute a response, and act. Although this document is
> >concerned with relatively simple artificial systems, living tissue may be
> >thought of as an active material. Living tissue is filled with protein
> >machines which gives living tissue properties (adaptability, growth,
> >self-repair, etc.) unimaginable in conventional materials.
> >Active materials can theoretically be made entirely of machines. These
> >are sometimes called swarms since they consist of large numbers of
> >identical simple machines that grasp and release each other and
> >exchange power and information to achieve complex goals. Swarms
> >change shape and exert force on their environment under software
> >control. Although some physical prototypes have been built, at least one
> >patent issued, and many simulations run, swarm potential capabilities
> >are not well analyzed or understood. We briefly discuss some concepts
> >here. For a summary of swarm concepts see [Toth-Fejel 96].
> >[Michael 94] proposes brick-shaped machines of various sizes that slide
> >past each other to assume a variety of shapes. He has generated a large
> >number of videos showing computer simulations of simple motions.
> >Although his web site contains rather extravagant claims, this work has
> >received a U. K. patent.
> >[Yim 95] built a small swarm with macroscopic (size in inches)
> >components called polypod, built a simulator of polypod, and
> >programmed it to move in various ways to study locomotion. There are
> >two brick shaped components in polypod, one of which has two
> >prismatic joints linked by a revolute joint. The second component is a
> >cubic connector with no mechanical motion. Polypod is programmed by
> >tables for each member of the swarm. Each member is programmed to
> >move at various speeds in each degree of freedom for certain amounts of
> >time. The swarm components are implicitly synchronized so there is no
> >clock signal.
> >[Hall 96] proposes a swarm with 10 micron dodecahedral components
> >each with 12 arms that can move in and out, rotate a little, and grab and
> >release each other. This concept is called the "utility fog." [Hall 96]
> >estimates that the utility fog would have a density of 0.2, tensile strength
> >of 1000 psi in action and 100,000 psi in a passive mode, and have a
> >maximum shear rate of 100 km/second/meter.
> >[Bishop 95] proposes a swarm consisting of 100 nanometer
> >brick-shaped components that slide past each other to change shape.
> >[Globus 97] proposes a swarm with two kinds of components -- edges
> >and nodes. The terms "node" and "edge" are chosen to correspond to
> >those in graph theory. The roughly spherical nodes are capable of
> >attaching to five edges (for a tetrahedral geometry with one free edge
> >per node) and rotating each edge in pitch and yaw. The rod-like edges
> >are capable of changing length, rotating around their long axis, and
> >attaching/detaching to/from nodes. See figure.
> >Component design, power distribution and control software are
> >significant challenges for swarm development. Consider that with 10
> >micron components a cubic meter of swarm would contain about 1015
> >devices, each with an internal computer communicating with its
> >neighbors to accomplish a global task.
> >NASA Missions
> >NASA's mission is divided into five enterprises: Mission to Planet
> >Earth, Aeronautics, Human Exploration and Development of Space,
> >Space Science, and Space Technology. We will examine some potential
> >nanotechnology applications in each area.
> >Mission to Planet Earth
> >EOS Data System
> >The Earth Observing System (EOS) will use satellites and other
> >systems to gather data on the Earth's environment. The EOS data
> >system will need to process and archive >terabyte per day for the
> >indefinite future. Simply storing this quantity of data is a significant
> >challenge -- each day's data would fill about 1,000 DVD disks. With
> >projected write-once nanomemory densities of 1015 bytes/cm2
> >[Bauschlicher 97a] a year's worth of EOS data can be stored on a small
> >piece of diamond. With projected nanocomputer processing speeds of
> >1018 MIPS [Drexler 92a], a million calculations on each byte of one
> >day's data would take one second on the desktop.
> >Smart Dust
> >Given a mature nanotechnology, it should be possible to build sensors in
> >balloon-borne systems approximately the size of bacteria. With
> >replication based manufacturing, these should be quite inexpensive. If
> >the serious communication and control problems can be solved, one can
> >imagine spreading billions of tiny lighter-than-air vehicles into the
> >atmosphere to measure wind currents and atmospheric composition. A
> >similar approach might be taken in the oceans -- note that the oceans
> >are full of floating microscopic living organisms that can sense and react
> >to their environment. Smart dust might sense the environment, note
> >the location via a GPS-like system, and store that information until
> >close enough to a data-collection point to transfer the data to the
> >outside world.
> >Aeronautics and Space Transportation
> >The strength of materials and computational capabilities previously
> >discussed for space transportation should also allow much more
> >advanced aircraft. Stronger, lighter materials can obviously make
> >aircraft with greater lift and range. More powerful computers are
> >invaluable in the design stage and of great utility in advanced avionics.
> >Active surfaces for aeronautic control
> >MEMS technology has been used to replace traditional large control
> >structures on aircraft with large numbers of small MEMS controlled
> >surfaces. This control system was used to operate a model airplane in a
> >windtunnel. Nanotechnology should allow even finer control -- finer
> >control than exhibited by birds, some of which can hover in a light
> >breeze with very little wing motion. Nanotechnology should also enable
> >extremely small aircraft.
> >Complex Shapes
> >A reasonably advanced nanotechnology should be able to make simple
> >atomically precise materials under software control. If the control is at
> >the atomic level, then the full range of shapes possible with a given
> >material should be achievable. Aircraft construction requires complex
> >shapes to accommodate aerodynamic requirements. With molecular
> >nanotechnology, strong complex-shaped components might be
> >manufactured by general purpose machines under software control.
> >Payload Handling
> >The aeronautics mission is responsible for launch vehicle development.
> >Payload handling is an important function. Very efficient payload
> >handling might be accomplished by a very advanced swarm. The
> >sequence begins by placing each payload on a single large swarm located
> >next to the shuttle orbiter. The swarm forms itself around the payloads
> >and then moves them into the payload bay, arranging the payloads to
> >optimize the center of gravity and other considerations. The swarm
> >holds the payload in place during launch and may even damp out some
> >launch vibrations. On orbit, satellites can be launched from the payload
> >bay by having the swarm give them a gentle push. The swarm can then
> >be left in orbit, perhaps at a space station, and used for orbital
> >This scenario requires a very advanced swarm that can operate in an
> >atmosphere and on orbit in a vacuum. Besides the many and obvious
> >difficulties of developing a swarm for a single environment, this
> >provides additional challenges. Note that a simpler swarm might be used
> >for aircraft payload handling.
> >Vehicle Checkout
> >Aerospace vehicles often require complex checkout procedures to
> >insure safety and reliability. This is particularly true of reusable launch
> >vehicles. A very advanced swarm with some special purpose appendages
> >might be placed on a vehicle. It might then spread out over the vehicle
> >and into all crevices to examine the state of the vehicle in great detail.
> >Human Exploration and Development of Space
> >Nanotechnology-enabled Earth-to-orbit transportation has the
> >greatest potential to revolutionize human access to space by dropping
> >the current $10,000 per pound cost of launch, but this was discussed
> >above. Other less dramatic technologies include:
> >High Strength and Reliability Materials
> >Space structures with a long design life (such as space station modules)
> >need high-reliability materials that do not degrade. Active materials
> >might help. The machines monitor structural integrity at the
> >sub-micrometer scale. When a portion of the material becomes
> >defective, it could be disassembled and then correctly reassembled. It
> >should be noted that bone works somewhat along these lines. It is
> >constantly being removed and added by specialized cells.
> >On Demand Spares and Tools
> >To effect timely repairs, space stations require a large store of spare
> >parts and tools that are rarely used. A mature nanotechnology might
> >create a "matter compiler," a machine that converts raw materials into
> >a wide variety of products under software control. Contemporary
> >examples of very limited matter compilers are numerically controlled
> >machines and polypeptide sequencers. With a substantially more
> >capable nanotechnology-based matter compiler, a space station crew
> >could simply make spare parts and tools as needed. The programs could
> >be stored on-board or on the ground. New tools invented on Earth could
> >be transferred as software to the station for manufacture. Once used,
> >unneeded tools and broken parts could be ionized in a solar furnace,
> >transferred using controlled magnetic fields, and the constituent atoms
> >stored for later manufacture into new products.
> >Waste Recycling
> >An advanced nanotechnology might be able to build filters that
> >dynamically modify themselves to attract the contaminant molecules
> >detected by the air and water quality sensors. Once attached to the filter,
> >the filter could in principle move the offending molecules to a
> >molecular laboratory for modifications to useful or at least inert
> >products. A swarm might implement such an active filter if it was able
> >to dynamically manufacture proteins that could bind contaminant
> >molecules. The protein and bound contaminant might then be
> >manipulated by the swarm for transportation.
> >With a sufficiently advanced nanotechnology it might even be possible
> >to directly generate food by non-biological means. Then agriculture
> >waste in a self-sufficient space colony could be converted directly to
> >useful nutrition. Making this food attractive will be a major challenge.
> >Sleeping through RCS firings
> >Sleeping crew members in the shuttle experience considerable pain and
> >sleep disruption when the reaction control system fires and they collide
> >with the cabin walls. If crew members were connected to the walls by a
> >swarm, the swarm could absorb most or all of the force before the crew
> >member struck the wall. The swarm could then gradually return the
> >crew member to center (without the oscillations associated with bungee
> >cords) in preparation for the next firing.
> >Spacecraft Docking
> >For resupply, spacecraft docking is a frequent necessity in space station
> >operations. When two spacecraft are within a few meters of each other,
> >a swarm could extend from each, meet in the middle, and form a stable
> >connection before gradually drawing the spacecraft together.
> >Zero and Partial G Astronaut Training
> >A swarm could support space-suited astronauts in simulated partial-g
> >environments by holding them up appropriately. The swarm moves in
> >response to the astronaut's motion providing the appropriate simulation
> >of partial or 0 gravities. Tools and other objects are also manipulated by
> >the swarm to simulate non-standard gravity.
> >Smart Space Suits
> >Active nanotechnology materials (see active materials) might enable
> >construction of a skin-tight space suit covering the entire body except
> >the head (which is in a more conventional helmet). The material senses
> >the astronaut's motions and changes shape to accommodate it. This
> >should eliminate or substantially reduce the limitations current systems
> >place on astronaut range of motion.
> >Small Asteroid Retrieval
> >In situ resource utilization is undoubtedly necessary for large scale
> >colonization of the solar system. Asteroids are particularly promising
> >for orbital use since many are in near Earth orbits. Moving asteroids
> >into low Earth orbit for utilization poses a safety problem should the
> >asteroid get out of control and enter the atmosphere. Very small
> >asteroids can cause significant destruction. The 1908 Tunguska
> >explosion, which [Chyba 93) calculated to be a 60 meter diameter stony
> >asteroid, leveled 2,200 km2 of forest. [Hills 93] calculated that 4 meter
> >diameter iron asteroids are near the threshold for ground damage. Both
> >these calculations assumed high collision speeds. At a density of 7.7
> >g/cm3 [Babadzhanov 93], a 3 meter diameter asteroid should have a
> >mass of about 110 tons. [Rabinowitz 97] estimates that there are about
> >one billion ten meter diameter near Earth asteroids and there should be
> >far more smaller objects.
> >For colonization applications one would ideally provide the same
> >radiation protection available on Earth. Each square meter on Earth is
> >protected by about 10 tons of atmosphere. Therefore, structures orbiting
> >below the van Allen belts would like 10 tons/meter2 surface area
> >shielding mass. This would dominate the mass requirements of any
> >system and require one small asteroid for each 11 meter2 of colony
> >exterior surface area. A 10,000 person cylindrical space colony such as
> >Lewis One [Globus 91] with a diameter of almost 500 meters and a
> >length of nearly 2000 meters would require a minimum of about 90,000
> >retrieval missions to provide the shielding mass. The large number of
> >missions required suggests that a fully automated, replicating
> >nanotechnology may be essential to build large low Earth orbit colonies
> >from small asteroids.
> >A nanotechnology swarm along with an atomically precise lightsail is a
> >promising small asteroid retrieval system. Lightsail propulsion insures
> >that no mass will be lost as reaction mass. The swarm can control the
> >lightsail by shifting mass. When a target asteroid is found, the swarm
> >spreads out over the surface to form a bag. The interface to the sail must
> >be active to account for the rotation of the asteroid -- which is unlikely
> >to have an axis-of-rotation in the proper direction to apply thrust for
> >the return to Earth orbit. The active interface is simply swarm elements
> >that transfer between each other to allow the sail to stay in the proper
> >orientation. Of course, there are many other possibilities for
> >nanotechnology based retrieval vehicles.
> >Extraterrestrial Materials Utilization
> >Extraterrestrial materials brought into orbit could be fed into a
> >high-temperature solar furnace and partially ionized. Magnetic fields
> >might then be used to separate the nuclei. These are fed in appropriate
> >quantities to a matter-compiler to build the products desired.
> >Medical Applications
> >Several authors, including [Freitas 98] have speculated that a
> >sufficiently advanced nanotechnology could examine and repair cells at
> >the molecular level. Should this capability become available --
> >presumably driven by terrestrial applications -- the small size and
> >advanced capabilities of such systems could be of great utility on long
> >duration space flights and on self-sufficient colonies.
> >Self-replicating systems permit efforts of great scope to be pursued
> >economically. Adjusting the environment on another planet to suit the
> >tastes of humans is one such undertaking. Heating and cooling can be
> >achieved by (among many other methods) using space-based mirrors.
> >Chemical modifications of the planetary surface and atmosphere can be
> >achieved in relatively short periods by the use of self-replicating
> >systems that absorb sunlight and raw materials, and convert them into
> >the desired products. Much as plants changed the environment of the
> >earth to what we see today, so self-replicating molecular manufacturing
> >systems might more rapidly convert the environments of other planets.
> >Suspended Animation
> >As interstellar trips might last many years, the ability to conserve
> >supplies by maintaining some crew members in a suspended state would
> >be useful. An extremely advanced nanotechnology might use molecular
> >manipulations of each cell to provide (a) better methods of slowing or
> >suspending the metabolic activity of crew members and (b) better
> >methods of restoring metabolic activity to a normal state when the
> >destination is reached.
> >Space Science
> >Space Telescopes
> >Molecular manufacturing should enable the creation of very precise
> >mirrors. Unlike lightsail applications, telescope mirrors require a very
> >precise and somewhat complicated shape. A swarm with special purpose
> >appendages capable of bonding to the mirror might be able to achieve
> >and maintain the desired shape.
> >Virtual Sample Return
> >A very advanced nanotechnology would be capable of imaging and then
> >removing the surface atoms of an extra-terrestrial sample. By removing
> >successive surface layers the location of each atom in the sample might
> >be recorded, destroying the sample in the process. This data could then
> >be sent to Earth. Besides requiring a very advanced nanotechnology,
> >there is a more fundamental -- but not necessarily fatal -- problem: as
> >the outside layer of atoms is removed the next layer may rearrange itself
> >so the sample is not necessarily perfectly recorded.
> >Meteorological Data
> >As described earlier in the EOS section, smart dust could be distributed
> >into the atmosphere of another planet to characterize it in great detail.
> >Space Technology
> >Solar Power
> >Low Earth orbit spacecraft generally depend on solar cells and batteries
> >for power. According to [Drexler 92b]:
> > For energy collection, molecular manufacturing can be used
> > to make solar photovoltaic cells at least as efficient as those
> > made in the laboratory today. Efficiencies can therefore be >
> > 30%. In space applications, a reflective optical concentrator
> > need consist of little more than a curved aluminum shell <
> > 100 nanometers thick (photovoltaic cells operate with higher
> > efficiency at high optical power densities). A metal fin with a
> > thickness of 100 nanometers and a conduction path length of
> > 100 microns can radiate thermal energy at a power density as
> > high as 1000 W/m2 with a temperature differential from base
> > to tip of < 1 K.
> > Accordingly, solar collectors can consist of arrays of
> > photovoltaic cells several microns in thickness and diameter,
> > each at the focus of a mirror of ~100 micron diameter, the
> > back surface of which serves as a ~100 micron diameter
> > radiator. If the mean thickness of this system is ~1 micron,
> > the mass is ~10-3 kg/m2 and the power per unit mass, at
> > Earth's distance from the Sun, where the solar constant is
> > ~1.4 kW/m2, is > 105 W/kg."
> >By comparison, the U.S. built Photovoltaic Panel Module solar cells
> >currently used on the Mir Space Station and planned for use on the
> >International Space Station generate about 118 W/kg.
> >Power Storage
> >Fuel Cells
> >A critical component in hydrogen/oxygen fuel cells is the PEM (Proton
> >Exchange Membrane). This membrane must (a) permit the passage of
> >protons while (b) blocking everything else. Present membranes do a
> >rather poor job. One group at Ames is designing and computationally
> >testing PEMs to study possible energy mechanisms in early life. While
> >these studies are not meant to design optimal membranes for fuel cell
> >use, the basic knowledge and approach may be of value. Another
> >proposal is to design a diamond membrane a few nanometers thick with
> >"proton pores." The pores might be lined with fluorine, oxygen and
> >nitrogen to create a region with a high proton affinity. In addition, a
> >positionally controlled platinum might be held at the mouth of the pore
> >to verify that H2 can be catalytically split into H+ and e-, and that the
> >barrier for migration of the H+ into the pore is modest in size.
> >Nanotechnology must provide precise control over the manufacturing
> >process of the diamondoid PEM since the pores must be made very
> >Hydrogen Storage
> >Studies of H2 absorption and packing in carbon nanotubes and
> >nanoropes are in progress at NASA Ames and elsewhere. Nanotubes
> >provide large pore sizes and nanoropes have different pore sizes
> >depending on interstitial and other locations. [Dillon 97] estimated that
> >the single walled nanotubes in their sample contained 5 to 10% by
> >weight of H2. The nanotubes were about 0.1 to 0.2% by weight of the
> >total sample. Computational studies at Ames suggest that to store
> >7-10% H2 in single walled nanotubes at room temperature the H2s must
> >be stored inside the tubes, not merely adsorbed on the walls [Srivastava
> >97d]. This work suggests that carbon nanotubes might be developed into
> >an excellent H2 storage medium within 3-5 years.
> >Oxygen Storage
> >Calculations with oxygen [Merkle 94] suggest that a diamondoid sphere
> >~0.1 microns in diameter should easily hold oxygen at ~1,000
> >atmospheres. While higher pressures are feasible, they offer declining
> >returns. At higher pressures, the pressure-volume relationship becomes
> >severely non-linear and the density approaches a limiting value. Other
> >gases might also be stored if diamondoid spheres can be built, but the
> >analysis has not been done.
> >Fly Wheels
> >High strength light-weight materials will allow greater efficiency of
> >energy storage as angular momentum.
> >Nano Electromechanical Sensors
> >Many kinds of ultraminiature electromechanical devices have utility on
> >a miniaturized space craft. It has been shown that manipulating carbon
> >nanotubes changes their electrical properties [Srivastava 97b]. This
> >might be exploited to build nanometer scale strain devices. This may be
> >achievable within 3-5 years, and simulations along these lines are in
> >Similar results have been achieved experimentally with C60 [Joachim
> >97]. The electrical properties of a C60 molecule were changed by
> >applying pressure to the molecule with an SPM tip.
> >Miniature Spacecraft
> >Smaller, lighter spacecraft are cheaper to launch (current costs are
> >about $10,000/lb) and generally cheaper to build. Diamondoid structural
> >materials can radically reduce structural mass, miniaturized electronics
> >can shrink the avionics and reduce power consumption, and atomically
> >precise materials and components should shrink most other subsystems.
> >Thermal Protection
> >Thermal protection is crucial for atmospheric reentry and other tasks.
> >The carbon nanotubes under investigation at NASA Ames and
> >elsewhere may play a significant role. Most production processes for
> >carbon nanotubes create a tangled mat of nanotubes that has a very low
> >mass-to-volume ratio. Like graphite, the tubes should withstand high
> >temperatures but the tangled mat should prevent them from ablating.
> >This may lead to high temperature applications.
> >Many of the applications discussed here are speculative to say the least.
> >However, they do not appear to violate the laws of physics. Something
> >similar to these applications at these performance levels should be
> >feasible if we can gain complete control of the three-dimensional
> >structure of materials, processes and devices at the atomic scale.
> >How to gain such control is a major, unresolved issue. However, it is
> >clear that computation will play a major role regardless of which
> >approach -- positional control with replication, self-assembly, or some
> >other means -- is ultimately successful. Computation has already played
> >a major role in many advances in chemistry, SPM manipulation, and
> >biochemistry. As we design and fabricate more complex atomically
> >precise structures, modeling and computer aided design will inevitably
> >play a critical role. Not only is computation critical to all paths to
> >nanotechnology, but for the most part the same or similar
> >computational chemistry software and expertise supports all roads to
> >molecular nanotechnology. Thus, even if NASA's computational
> >molecular nanotechnology efforts should pursue an unproductive path,
> >the expertise and capabilities can be quickly refocused on more
> >promising avenues as they become apparent.
> >As nanotechnology progresses we may expect applications to become
> >feasible at a slowly increasing rate. However, if and when a general
> >purpose programmable assembler/replicator can be built and operated,
> >we may expect an explosion of applications. From this point, building
> >new devices will become a matter of developing the software to instruct
> >the assembler/replicators. Development of a practical swarm is another
> >potential turning point. Once an operational swarm that can grow and
> >divide has been built, a large number of applications become software
> >projects. It is also important to note that the software for swarms and
> >assembler/replicators can be developed using simulators -- even before
> >operational devices are available.
> >Nanotechnology advocates and detractors are often preoccupied with
> >the question "When?" There are three interrelated answers to this
> >question (see also [Merkle 97] and [Drexler 91]):
> > 1.Nobody knows. There are far too many variables and unknowns.
> > Beware of those who have excessive confidence in any date.
> > 2.The time-to-nanotechnology will be measured in decades, not
> > years. While a few applications will become feasible in the next
> > few years, programmable assembler/replicators and swarms will be
> > extremely difficult to develop.
> > 3.The time-to-nanotechnology is very sensitive to the level of
> > effort expended. Resources allocated to developing
> > nanotechnology are likely to be richly rewarded, particularly in the
> > long term.
> >We would like to thank Steve Zornetzer, NASA Ames Research
> >Center, for asking us to look into molecular nanotechnology
> >applications to NASA missions. Special thanks to Glenn Deardorff and
> >Chris Henze for reviewing the manuscript.
> >[Avouris 96] Ph. Avouris, R. E. Walkup, A. R. Rossi, H. C. Akpati, P.
> >Nordlander, P.-C. Shen, G. G. Ablen and J. W. Wyding, "Breaking
> >Individual Chemical Bonds via STM-Induced Exitations," Surface
> >Science, 1 August 1996, V363 N1-3:368-377.
> >[Babadzhanov 1993] Pulat B. Babadzhanov, "Density of meteoroids and
> >their mass influx on the Earth,"Asteroids, Comets, Meteors 1993,
> >Proceedings of the 160th symposium of the International Astronomical
> >Union, Belgirate, Italy, 14-18 June 1993, A. Milani, M. Di Martino and
> >A. Cellino, editors, pages 45-54.
> >[Bauschlicher 97a] Charles W.Bauschlicher Jr., Alessandra Ricca and
> >Ralph Merkle, "Chemical storage of data," Nanotechnology, volume 8,
> >number 1, March 1997 pages 1-5.
> >[Bauschlicher 97b] Charles. W. Bauschlicher and M. Rosi,
> >"Differentiating between hydrogen and fluorine on a diamond surface",
> >submitted to Theor. Chem. Acta.
> >[Bauschlicher 97c] Charles. W. Bauschlicher and M. Rosi, unpublished.
> >[Bishop 95] Forrest Bishop, "The Construction and Utilization of Space
> >Filling Polyhedra for Active Mesostructures," WWW page.
> >[Bumm 96] L. A. Bumm, J. J. Arnold, M. T. Cygan, T. D. Dunbar, T. P.
> >Burgin, L. Jones II, D. L. Allara, James M. Tour, P. S. Weiss, "Are
> >Single Molecular Wires Conducting?" Science, volume 271, 22 March
> >1996, pages 1705-1707.
> >[Chico 96] L. Chico, Vincent H. Crespi, Lorin X. Benedict, Steven G.
> >Louie and Marvin L. Cohen, "Pure Carbon Nanoscale Devices:
> >Nanotube Heterojunctions," Physical Review Letters, volume 76,
> >number 6, 5 February 1996, pp. 971-974.
> >[Chyba 93] Christopher F. Chyba, Paul J. Thomas, and Kevin J. Zahnle,
> >"The 1908 Tunguka explosion: atmospheric disruption of a stony
> >asteroid," Nature volume 361, 7 January 1993, pages 40-44.
> >[Dai 96] H. Dai, J. H. Hafner, A. G. Rinzler, D. T. Colbert and R. E.
> >Smalley, "Nanotubes as Nanoprobes in Scanning Probe Microscopy,"
> >Nature 384, pages 147-151, (1996).
> >[Dillon 97] A. C. Dillon, K. M. Jones, T. A. Bekkedahl, C. H. Kiang, D.
> >S. Bethune, M. J. Heben, "Storage of hydrogen in single-walled carbon
> >nanotubes," Nature, 27 March 1997, volume 386, N6623:377-379.
> >[Dresselhaus 95] M. S. Dresselhaus, G. Dresselhaus and P. C. Eklund,
> >Science of Fullerenes and Carbon Nanotubes, Academic Press (1995).
> >[Drexler 91] K. Eric Drexler, Chris Peterson, and Gayle Pergami,
> >Unbounding the Future, William Morrow and Company, Inc., (1991).
> >[Drexler 92a] K. Eric Drexler, Nanosystems: Molecular Machinery,
> >Manufacturing, and Computation, John Wiley & Sons, Inc. (1992).
> >[Drexler 92b] K. Eric Drexler, Journal of the British Interplanetary
> >Society, volume 45, number 10, pages 401-405 (1992).
> >[Freitas 98] Robert A. Freitas Jr., Nanomedicine, Volume I: Basic
> >Capabilities , Landes Bioscience, Georgetown TX, 1998.
> >[Globus 91] Al Globus, "The Design and Visualization of a Space
> >Biosphere," 10th Biennial Space Studies Institute/Princeton University
> >Conference on Space Manufacturing, Princeton University, May 15-18,
> >[Globus 97], Al Globus, Charles Bauschlicher, Jie Han, Richard Jaffe,
> >Creon Levit, Deepak Srivastava, "Machine Phase Fullerene
> >Nanotechnology," Nanotechnology, 9, pp. 1-8 (1998).
> >[Goldhaber-Gordon 97] D. J. Goldhaber-Gordon, M. S. Montemerlo, J.
> >C. Love, G. J. Opiteck, and J. C. Ellenbogen, Proceedings of the IEEE,
> >April 1997, V85 N4:521-540.
> >[Hall 96] J. Storrs Hall, "Utility Fog: The Stuff that Dreams are Made
> >Of," Nanotechnology: Molecular Speculations on Global Abundance,
> >B. C. Crandall, editor, MIT Press, Cambridge, Massachusetts, 1996; also
> >in "Utility Fog," Extropy, 3rd (Part 1) and 4th quarter (Part 2), 1994. See
> >WWW page Utility Fog: The Stuff that Dreams are Made Of.
> >[Han 97a] Jie Han, Al Globus, Richard Jaffe and Glenn Deardorff,
> >"Molecular Dynamics Simulation of Carbon Nanotube Based Gears,"
> >Nanotechnology, volume 8, number 3, 3 September 1997, pages 95-102.
> >[Han 97b] Jie Han, M. P. Anantram, and Richard Jaffe, "Design and
> >Study of Carbon Nanotube Electronic Devices," The Fifth Foresight
> >Conference on Molecular Nanotechnology, 5-8 November, 1997, Palo
> >Alto, CA.
> >[Han 97c] Jie Han, Al Globus, and Richard Jaffe, "The Molecular
> >Dynamics of Carbon Nanotube Gears in He and Ne Atomspheres," The
> >Fifth Foresight Conference on Molecular Nanotechnology, 5-8
> >November, 1997; Palo Alto, CA.
> >[Hills 93] Jack G. Hills and M. Patrick Goda, "The fragmentation of
> >small asteroids in the atmosphere," The Astronomical Journal, March
> >1993, volume 105, number 3, pages 1114-1144.
> >[Iijima 91] Sumio Iijima, "Helical microtubules of graphitic carbon,"
> >Nature, 7 November 1991, volume 354, N6348:56-58.
> >[Issacs 66] John D. Issacs, Allyn C. Vine, Hugh Bradner and George E.
> >Bachus, "Satellite Elongation into a True 'Sky-Hook'," Science, volume
> >151, 11 February 1966, pages 682-683.
> >[Joachim 97] C. Joachim and J. Gimzewski, "An Electromechanical
> >Amplifier Using a Single Molecule," Chemical Physics Letters, volume
> >265, pages 353-357, 1997.
> >[McKendree 95] Tom McKendree, "Implications of Molecular
> >Nanotechnology: Technical Performance Parameters on Previously
> >Defined Space System Architectures," The Fourth Foresight Conference
> >on Molecular Nanotechnology, Palo Alto, CA. (November 1995).
> >[Menon 97a] M. Menon, D. Srivastava and S. Saini, "Carbon Nanotube
> >Junctions as Building Blocks for Nanoscale Electronic Devices,"
> >Semiconductor Device Modeling Workshop at NASA Ames Research
> >Center, August (1997).
> >[Menon 97b] M. Menon and D. Srivastava, "Carbon Nanotube
> >T-junctions: Nanoscale Metal-Semiconductor-Metal Contact
> >Devices," submitted to Phys. Rev. Lett., (1997).
> >[Merkle 94] Ralph C. Merkle, "Nanotechnology and Medicine,"
> >Advances in Anti-Aging Medicine, Vol. I, edited by Dr. Ronald M.
> >Klatz, Liebert Press, 1996, pages 277-286.
> >[Merkle 96] Ralph C. Merkle and K. Eric Drexler, "Helical Logic,"
> >Nanotechnology (1996) volume 7 pages 325-339.
> >[Merkle 97] Ralph C. Merkle, "How long will it take to develop
> >nanotechnology?" WWW page.
> >[Michael 94] Joseph Michael, UK Patent #94004227.2.
> >[Moore 75] Gordon Moore, "Progress in digital integrated circuits,"
> >1975 International Electron Devices Meeting, page 11. See the figure:
> >approximate component count for complex integrated circuits vs. year
> >of introduction and the following figures from Miniaturization of
> >electronics and its limits, by R. W. Keyes, IBM Journal of Research and
> >Development, Volume 32, Number 1, January 1988.
> > Number of atoms used to store a bit in discrete magnetic entities
> > and in file technologies.
> > The decreasing number of dopant impurities in the base of bipolar
> > transistors for logic.
> > The decreasing energy dissipated per logic operation.
> >[Pearson 75] Jerome Pearson, Acta Astronautica 2 pages 785-799
> >[Rabinowitz 97] David L. Rabinowitz, "Are Main-Belt Asteroids a
> >Sufficient Source for the Earth-Approaching Asteroids? Part II.
> >Predicted vs. Observed Size Distributions," Icarus 1997 May, V127
> >[Smith 97] Steven. S. Smith, Luming M. Niu, David J. Baker, John A.
> >Wendel, Susan E. Kane, and Darrin S. Joy, "Nucleoprotein-based
> >nanoscale assembly," Proceedings of the National Academy of Sciences
> >of the United States of America, March 18 1997, V94 N6:2162-2167.
> >[Srivastava 97a] Deepak Srivastava and Steve T. Barnard, "Molecular
> >Dynamics Simulation of Large-Scale Carbon Nanotubes on a Shared
> >Memory Architecture," SuperComputing 97 (1997).
> >[Srivastava 97b] Deepak Srivastava, Steve T. Barnard, S. Saini and M.
> >Menon, "Carbon Nanotubes: Nanoscale Electromechanical Sensors",
> >2nd NASA Semiconductor Device Modeling Workshop at NASA Ames
> >Research Center, August 1997.
> >[Srivastava 97c] Deepak Srivastava, "Molecular Dynamics Simulations
> >of Laser Powered Carbon Nanotube Gears," submitted to
> >[Srivastava 97d] Deepak Srivastava, "H2 packing in Single Wall Carbon
> >Nanotubes and Ropes by Molecular Dynamics Simulations,"
> >unpublished (1997).
> >[Taylor 93] R. Taylor and D. R. M. Walton, "The Chemistry of
> >Fullerenes," Nature, volume 363, N6431, 24 June 1993, pages 685-693.
> >[Thummel 97] H. T. Thummel and C. W. Bauschlicher, "On the
> >reaction of FNO2 with CH3, t-butyl, and C13H21," J. Phys. Chem., 101,
> >1188 (1997).
> >[Toth-Fejel 96] Tihamer Toth-Fejel, "LEGO(TM)s to the Stars:
> >Active MesoStructures, Kinetic Cellular Automata, and Parallel
> >Nanomachines for Space Applications," The Assembler, Volume 4,
> >Number 3, Third Quarter, 1996
> >[Tour 96] James M. Tour, "Conjugated Macromolecules of Precise
> >Length and Constitution. Organic Synthesis for the Construction of
> >Nanoarchitectures," Chemical Review, January-February 1996, volume
> >96, pages 537-553.
> >[Tour 97] James M. Tour, Masatoshi Kozaki and Jorge M. Seminario,
> >"Molecular Scale Electronics: Synthetic and Computational
> >Approaches To Nanoscale Digital Computing," unpublished 1997.
> >[Treacy 96] M. M. J. Treacy, T. W. Ebbesen and J. M. Gibson,
> >"Exceptionally High Young's Modulus Observed for Individual Carbon
> >Nanotubes," Nature 381, 678 (1996).
> >[Wowk 96] Bryan Wowk, "Phased Array Optics," Nanotechnology:
> >Molecular Speculations on Global Abundance, B. C. Crandall, editor,
> >MIT Press, Cambridge, Massachusetts, 1996.
> >[Wu 96] Ruilan Wu, Jeffry S. Schumm, Darren L. Pearson, and James
> >M. Tour, "Convergent Synthetic Routes to Orthogonally Fused
> >Conjugated Oligomers Directed towards Molecular Scale Electronic
> >Device Applications," Journal of Organic Chemistry, volume 61,
> >number 20, pages 6906-6921.
> >[Yacobson 96] Boris I. Yacobson, C. J. Brabec and J. Bernholc,
> >"Nanomechanics of Carbon Tubes - Instabilities Beyond Linear
> >Response," Physical Review Letters, 1 April 1996, V76 N14:2511-2514.
> >[Yim 95] Mark Yim, "Locomotion With A Unit-Modular
> >Reconfigurable Robot," Stanford University Technical Report
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