MM targeted development
From Wise Nano
Contents |
Targeted Development of Molecular Manufacturing
The high performance promised by molecular manufacturing will induce some organizations to consider whether they should work to hasten its development. This section explores some of the issues involved in such a decision, and some of the desiderata for a targeted development program.
Existing vs. Required Capabilities
In theory, all that is needed for an advanced nanofactory-type molecular manufacturing system is the ability to build precise structures of conductors and insulators. The conductors can be used for switches, as well as electrostatic motors and solenoids, and that is sufficient to build digital logic and actuated machinery. Mechanical systems can perform whatever tactile sensing is required to avoid accretion of errors.
In practice, the nanoscale is a rich source of new phenomena. There is no practical or theoretical reason to exclude any phenomenon that is useful. In recent years, non-bleaching chromophores, mechanical programmable DNA-building systems made of DNA, several new kinds of molecular actuators, and many other helpful and relevant technologies have been developed by nanoscale technology researchers. This provides ample reason why a molecular manufacturing program will benefit from and further motivate existing nanoscale technology research.
Currently, most nanoscale technology research is not targeted at the development of nanoscale construction equipment. The synthesis of stiff covalent solids in arbitrary shapes is beyond the capabilities of today's unguided solution chemistry, so such structures have received little attention. However, they are a natural fit for building with nanoscale mechanosynthesis. Likewise, conventional mechanical engineering at the nanoscale would be difficult with the soft and flexible molecules that are available from many of the solution chemistry and biomolecular lines of research. With stiff covalent solids, nanoscale mechanical engineering requires substantial modifications from macro-scale practice, but is not completely alien.
The emphasis on mechanical rather than electronic functionality confers temporary limitations on molecular manufacturing, but also substantial advantages. Nanoscale mechanics depends on atoms, which are far heavier than electrons. This means that many quantum or unfamiliar phenomena can be factored out of the analysis of many machines. There is no need to use the full palette of nanoscale phenomena, because the basic task of molecular manufacturing is quite simple: to join molecules repetitively and reliably, in programmable location or sequence, and then to perform ordinary mechanical operations on the result.
In summary, a targeted molecular manufacturing development program would encourage basic research in a wide range of nanoscale technologies, while working to develop nanoscale substances, tools, and engineering disciplines that are not much emphasized today. Although a development program may be accelerated by future nanoscale science breakthroughs, and would do well to cultivate them, development does not appear to be dependent on any additional fundamental breakthroughs.
Evaluating the need for targeted development
Several questions must be asked and answered in order to decide whether it is in an organization's best interest to expend resources on working toward molecular manufacturing in a targeted way. Several different kinds of factors will influence the decision.
The first question is the ultimate capability of molecular manufacturing and its products. A closely related question is how soon that capability might be developed, and how it will compare with competing technologies which will exist at that time. It is worth noting that development of even primitive general-purpose nanoscale manufacturing would probably facilitate rapid development of improved versions. In other words, development of a molecular manufacturing platform that can build products only slightly ahead of the competing technologies could result in the rapid development of more advanced capabilities. The development trajectory of a rapid-prototyped technology would likely advance more quickly than a competing trajectory which did not have the benefits of rapid prototyping. Thus, it is likely that whatever the physical limits of molecular manufactured products are, an accelerated molecular manufacturing development effort will have a good chance of accessing those capabilities significantly in advance of their expected schedule.
The cost/benefit tradeoff of funding or not funding development should be considered. This includes the benefit to the organization of owning the technology, which must be balanced by the chance that the organization will be unable to retain ownership of its work due to competition or regulation. Another factor that should not be overlooked is the cost to the organization if molecular manufacturing is developed elsewhere in a way that locks them out. With such a powerful technology, it is easy—perhaps too easy—to predict winner-takes-all dynamics. More subtle questions include the relative merits of owning the technology vs. encouraging its broader growth for the indirect benefits, and the break-even point(s) for money spent vs. acceleration gained.
Although there is insufficient information to make a projection of development cost, it is likely that the cost is decreasing rapidly. Computers for simulation are becoming exponentially more capable, along with core molecular biology technologies that may be useful in development. Molecular manufacturing theory is continually advancing, finding cheaper and faster development pathways. The number of organizations that could launch a rapid development program will increase as cost decreases.
After considering the benefits and costs of various development scenarios, an organization may conclude that it should promote, ignore, or perhaps retard the development of molecular manufacturing. Separate strategies may have to be considered for the organization itself, its partners, and its competitors. Guidelines for implementing a strategy to promote development are discussed in the next section.
Guidelines for a targeted development program
A program targeted at rapidly developing advanced molecular manufacturing should choose goals extending several steps ahead. There are at least three possible pathways to develop an advanced system: direct scanning-probe manufacture of stiff machines; engineering of biomolecules to develop an improving series of biomimetic machines leading eventually to high-performance integrated systems; and fabrication of small molecular building blocks (not particularly biological) with which to build simple and improving nanomachine block-handling systems. Looking only one step ahead will provide no basis for choosing between these approaches. Selecting more ambitious goals and planning backward as well as forward will help in selecting an approach. (The other approaches could be pursued in the ongoing basic nanoscience effort, to allow their value to be developed in a less structured context.)
If a goal several steps ahead is known, then simulation may allow tentative designs to be developed in advance of laboratory capabilities. An important benefit of such activity is that, even if the simulation is not completely accurate, the experience will help to train designers for the time when the physical work catches up to the plans. To the extent that the simulations are accurate, development of workable designs can help to inform the next step, and a stockpile of designs verified in simulation can speed development once experiment catches up. Even if the simulations have to be adjusted to conform to experimental reality, the design stockpile will often provide a good starting point for revision rather than complete redesign.
An organizational culture should be developed that promotes creativity and exploration. Participants who do not see the value in pursuing approaches that are not guaranteed to work would hamper exploratory efforts. Many scientists are not comfortable building theories about unexplored areas of applied science. Of course, every idea needs to be critically evaluated before too much effort is spent on it. But critical evaluation should apply different standards in guiding exploratory work than in guiding major commitments to development strategies. Good ideas can be killed by premature demands for “proof,” and new ideas should have a chance to take root unless they are obviously and demonstrably flawed.
Along the same lines, acceptance of a high percentage of dead-end efforts will reduce development time, though there will be a tradeoff in cost. If only one idea at a time can be tried, then time and effort must be spent selecting the best one. If it turns out not to work, not only money but substantial time will have been lost; this will discourage the people involved from admitting that they should try a different idea. Conversely, if multiple ideas can be tried in parallel, then trying a less good idea costs considerably less time. An institutional structure that does not penalize abandoning a moribund approach will help to minimize the amount of effort spent on attempts to justify previous unfruitful effort.
Modular design, in which the goal is broken down into sub-goals which can be solved in any of several ways, will make it easier to plan multiple parallel efforts to solve pieces of the problem. For example, the method of joining building blocks has some effect on the design of the actuators. However, a well-designed but broadly conceived specification for actuator characteristics will allow a range of compatible block and actuator technologies to be developed in parallel.
Finally, the leaders of the program must remember that nanoscale technology and molecular manufacturing theory will continue to develop rapidly, and they must incorporate new advances in their program, either by refocusing existing efforts when sufficient reason arises, or if resources allow, starting new parallel efforts and allowing old efforts to dwindle naturally if and when people are tempted away to better approaches.
