Kinematic Self-Replicating Machines
© 2004 Robert A. Freitas Jr. and Ralph C. Merkle. All Rights Reserved.
Robert A. Freitas Jr., Ralph C. Merkle, Kinematic Self-Replicating Machines, Landes Bioscience, Georgetown, TX, 2004.
6.2.2 Demonstration of Feasibility
A second reason motivating a molecular assembler design project is to show feasibility. At the present time, not all members of the research community (and as a consequence not all decisionmakers) will agree that assemblers are possible. Molecular models of critical components and subsystems will provide both a more detailed technical analysis of the issues and also a basis for graphics, animations, and other visual aids that can vividly and compellingly communicate the salient issues. Clearly, devoting substantial resources to a project is made more difficult if there is significant doubt about its ultimate feasibility. A detailed design effort should lay such doubts to rest, at least within the most crucial scientific and engineering communities that closely follow research in this area.
Further, one or more credible published designs demonstrating feasibility should increase the absolute magnitude of the resources devoted to the development of a molecular assembler. A feasible design would drive home the point that assemblers are possible, a fact that would influence funding sources to direct additional resources towards their development. For instance, an issue of significant interest is the use of self replication to reduce manufacturing costs. Self replication is likely to have a revolutionary impact on the economics of manufacturing, driving the manufacturing cost per pound for most manufactured products down to levels seen in existing products made using a self-replicating manufacturing base, such as agricultural products (wood, wheat, etc.) or even lower. As an example, consider the impact of a one kilogram molecular memory with a storage capacity measured in moles of bits (a mole is ~6 x 1023, a unit of quantity common in chemistry) and an eventual total manufacturing cost, at least in principle, as low as $1-$1000 per kilogram, comparable to the prices of various products made by present-day biology-based self-replicating manufacturing systems (Table 6.1). The basic cost of production using a mature molecular manufacturing technology base, excluding development, distribution and legally-mandated costs, will be dominated by the price of materials (Nanosystems  at Section 14.5.6.h), which presently cost ~0.1-0.5 $/kg (e.g., propane for manufacturing diamond; Table 6.1). This alone would revolutionize computer hardware capabilities. Yet this is but a single example of the numerous consequences of molecular manufacturing – a manufacturing technology which will transform most other manufactured products equally profoundly.
A cautionary historical analogy can be mentioned in connection with the development of the scanning tunneling microscope (STM) which is now employed for direct atomic visualization and other useful purposes in molecular nanotechnology. While it is well known that Gerd Karl Binnig and Heinrich Rohrer received the Nobel Prize for inventing the STM in 1981 at an IBM laboratory in Zurich, Switzerland , what is perhaps less well known is that the first STM, complete with piezo scanning system, was almost invented a decade earlier . In 1971, Young, Ward and Scire reported metal-vacuum-metal tunneling experiments  and described a machine they had built  for these experiments at the National Bureau of Standards: “A noncontacting instrument for measuring the microtopography of metallic surfaces has been developed to the point where the feasibility of constructing a prototype instrument has been demonstrated.... In the MVM [metal-vacuum-metal] mode, the instrument is capable of performing a non-contacting measurement of the position of a surface to within about 3 Angstroms. The instrument can be used in certain scientific experiments to study the density of single and multiple atom steps on single crystal surfaces, absorption of gases, and processes involving electronic excitations at the surfaces.” Although close to constructing a complete STM, this early effort was frustrated when the researchers’ funding was suddenly cut in 1972, just as their work was about to bear fruit .
It is possible that potential funding sources have not yet internalized the magnitude of the benefits that can reasonably be expected from the development of molecular nanotechnology. A design illustrating basic feasibility should help some decisionmakers grasp the importance of the remarkable opportunities which confront us, and provide greater incentive to allocate resources to the entire research and development enterprise. In a 2003 public debate  with Richard Smalley, Eric Drexler observed that “U.S. progress in molecular manufacturing has been impeded by the dangerous illusion that it is infeasible. However, because it is a systems engineering goal, molecular manufacturing cannot be achieved by a collection of uncoordinated science projects. Like any major engineering goal, it will require the design and analysis of desired systems, and a coordinated effort to develop parts that work together as an integrated whole. Why does this goal matter? Elementary physical principles indicate that molecular manufacturing will be enormously productive. Scaling down moving parts by a factor of a million multiplies their frequency of operation – and in a factory, their productivity per unit mass – by the same factor. Building with atomic precision will dramatically extend the range of potential products, and decrease environmental impact as well. The resulting abilities will be so powerful that, in a competitive world, failure to develop molecular manufacturing would be equivalent to unilateral disarmament.”
On the other hand, the benefits may appear to other decisionmakers as “too good to be true,” a phenomenon David Berube calls “nanohype” . Cautions Drexler : “The very breadth of this range of applications has stimulated a reflexive rejection of the possibility of the enabling technology. This is, however, like rejecting data on the neutron-induced fission cross-section of the U-235 nucleus in 1940 because one disbelieves the possibility of a million-fold increase in the energy density of explosive devices. The magnitude of the expected consequences gives reason for careful evaluation of feasibility, not for emotional dismissals. Thus far, the dismissals have effectively inhibited the feasibility studies.” Berube  also observes that “venture capital sources have drained out due to the overuse of the nano prefix which seems to be attached to advanced MEMS research companies all over this country and abroad.”
Last updated on 1 August 2005