Well, one must consider although we now have achieved success pushing atoms around using SPM's, (ie. IBM's xenon atoms) we have not yet accomplished the feat of creating covalent bonds.(such as nature does) The closest we have come to this is Nadrian Seemans nanorobotic arm, made out of synthetic DNA. Until this point has occurred, an assembler will not.
In the meantime, this is the reason we are exposed to these nanoscale evolved technology. The more we create application's on the molecular scale, we find more windows of opprotunity for advances. There will most likely be in the near future, nanoscale resistors (Mitre corp.) and nanochips, quantum dots, nanowires etc. This is part of the process to getting to the big picture, and nanomachine (manipulator, replicator).
There are zillions of similar potential applications on the nanoscale. We will first see, paint on watches, retractable doors and floors, flat wall sized thin 3D tv's (holography), cars with total saftey measures, virtual reality games, doggy dung cleaners, hobbies such as railroad nanoscale models, refabrication of clothing, arrays anyways, I could go on, but these are the early applications of nano.
Nanomachines are composed of simple, nested geodesic skeletons and extensible rods, with no more computing power than today's personal computers. Not to tremendous a task to design machines with nanometer-scale components, but how do we construct them?
"One at a time". We can manipulate atoms at the nanometer scale and build more complex machinery at the micron scale. (e.g. computer chips) Given the pace of technological development, we will see machines of this complexity built by hand soon. But to be useful, we will need trillions of them- one trillion would fill a single cubic centimeter. Shortly after the first is built, they will be manufactured in quanity.
If a factory has ten million assemblers (that has taken years to create) each capable of producing ten thousand machines a day, it will take two weeks to produce a cubic centimeter of finished goods. During this period, nanomachine based products will be rare and expensive.
Eventually replicators will produce assemblers, which will then produce nanomachines for final use. This will be in constrained environments and will last for some time. Consumers at this time, will not have access to replicator technology, but will be a time filled with easily accessible nanomachinery. We may also use genetic engineering to in fact "rip off" the nanomachinery of living organisms to make nanomachines. This would lead to serious restrictions however. (depending)
Also involved in the construction of such a machine, is energy source-(most limiting aspect-nanomachines can be energy thirsty), communication-(machine parts able to interact with eachother and follow their commands), processing power-(each machine needs storage and computing facilities- 1,000times the computing power of today's personal computer), shape-(ie -buckyball or other micron-scale geodesic structure) and scale.
Gina "Nanogirl" Miller
>One thing I haven't noticed with nanotech research is that nobody
has yet developed a normal scale universal assembler, not to mention one that can replicate itself. From what I've seen, all nanotech companies are trying to build the final generation at the nanoscale first, which seems awfully bassackwards to me. Thats tantamount to having an R&D project during WWII to build a Pentium III chip. I say build a human scale assembler, that you can program to create any item wanted (especially items larger than itself), and then develop an assembler that can not only do that but replicate itself. Once this is achieved, work on making successive generations smaller until you get to the nano scale.
Gina "Nanogirl" Miller
"The science of nanotechnology, solutions for the future."