The nanotechnology we were promised

A response to my “Parricide” essay has been seen on IEEE’s Tech Talk blog. Dexter Johnson gives a fair summary of the positions taken to date, and says

As the argument seems to go, Drexler popularized the term nanotechnology in his book Engines of Creation, and so when the general public heard that thousands of scientists were working on “nanotechnology” of course they thought that table-top factories and nanobots were just around the corner. This is why nanotechnology has failed in its promise.

If I follow that logic, all would be well with the world if material scientists described their work at engineering and manipulating materials on the nanoscale to bring about novel properties as anything but “nanotechnology”.

Well, almost. We’re still concerned about the situation in Darfur. But it would have prevented some confusion. (Although why anyone would think that “X-technology” wouldn’t mean “building working machines in the regime X,” as does microtechnology, is beyond me.) But then Johnson, perhaps unintentionally, completely underscores my point:

And no doubt if this had held true, all the funding that now gets funneled into national nanotechnology initiatives around the world would either not exist at all or be aimed at quite different purposes.

Why would this valuable research not have gotten funded if it had happened to have a different name? Are the funding agencies driven by nothing but buzzwords? If so, the point is made; if not, why use a term that was bound to cause confusion and raise false hopes?

Let me go on record here as saying in the strongest of terms that basic science of the sort that the NNI supports should be funded and not one cent spent on it has been wasted in any reasonable sense. A billion dollars a year sounds like a lot of money but recently we’ve been spending more than that per day to prop up failed investment houses. Materials science, surface physics, macromolecular chemistry, and so forth should have been funded and they were. Nanotechnology should also have been funded and it was not. One tenth of one percent of the NNI budget would have funded an extremely valuable in-depth feasibility study of molecular manufacturing, for example. The possibility wasn’t ignored — it was actively excluded. (And again let me add that the situation is changing and it’s no longer politically incorrect to be working toward nanoscale machines or mechanosynthesis.)

One result of these different purposes might have been that today we would have much better computer-generated animation of how a table-top factory might work someday.

Well, yes — as part of that feasibility study, for example. And that might include better dry molecular dynamics force fields, more well-studied deposition reactions, better multimode multiscale simulation engines and CAD systems, and some more major insights into the math of scaling in manufacturing systems such as were discovered in the process of developing this one animation.

But let’s take Johnson at his word and assume that a billion a year had been spent on real nanotechnology from, say, 1989, the year of the first Foresight Conference on Nanotechnology. For the sake of as much concreteness as any such what if scenario can have, let’s suppose I had been running it personally. What might be different?

In 1960, after Feynman’s Plenty of Room at the Bottom talk, he gave a $1000 prize to William McClellan for constructing an electric motor that fit in a 1/64-inch cube. Feynman had envisioned a way to nanotechnology:

You know, in the atomic energy plants they have materials and machines that they can’t handle directly because they have become radioactive. To unscrew nuts and put on bolts and so on, they have a set of master and slave hands, so that by operating a set of levers here, you control the “hands” there, and can turn them this way and that so you can handle things quite nicely.

Most of these devices are actually made rather simply, in that there is a particular cable, like a marionette string, that goes directly from the controls to the “hands.” But, of course, things also have been made using servo motors, so that the connection between the one thing and the other is electrical rather than mechanical. When you turn the levers, they turn a servo motor, and it changes the electrical currents in the wires, which repositions a motor at the other end.

Now, I want to build much the same device—a master-slave system which operates electrically. But I want the slaves to be made especially carefully by modern large-scale machinists so that they are one-fourth the scale of the “hands” that you ordinarily maneuver. So you have a scheme by which you can do things at one- quarter scale anyway—the little servo motors with little hands play with little nuts and bolts; they drill little holes; they are four times smaller. Aha! So I manufacture a quarter-size lathe; I manufacture quarter-size tools; and I make, at the one-quarter scale, still another set of hands again relatively one-quarter size! This is one-sixteenth size, from my point of view. And after I finish doing this I wire directly from my large-scale system, through transformers perhaps, to the one-sixteenth-size servo motors. Thus I can now manipulate the one-sixteenth size hands.

Well, you get the principle from there on. It is rather a difficult program, but it is a possibility. You might say that one can go much farther in one step than from one to four. Of course, this has all to be designed very carefully and it is not necessary simply to make it like hands. If you thought of it very carefully, you could probably arrive at a much better system for doing such things.

In other words, along Feynman’s pathway to nanotechnology, manipulating things at the atomic scale is the last thing you do. I find much to like in Feynman’s scheme. If your goal is a widely-capable industrial base of productive machinery at scale B, and you already have a widely-capable industrial base of productive machinery at scale A, it doesn’t really make much sense to throw away the capabilities of your existing technology and poke around at scale B, at the very limited limits of your capabilities, just because you can.

One of the reasons for the disconnect between the current-day nanoscientists’ announcements and real-world products, as pointed out by Richard Jones in the original blog post, is that the scientists do in fact discover and build experimentally a wide variety of devices, from switching elements to actuators. But unlike at the macroscale, where if you have a new actuator you can turn right around and use it in a machine, the nanoscale stuff exists in isolation because there is no prosaic background of everyday manipulation and fabrication technology to make the new devices in quantity and assemble them into working systems.

Besides, even if you do have working nanomachines, to make systems that do real-world tasks you tend to need machinery at every intermediate scale anyway, as illustrated in this early concept for the nanofactory:

So instead of starting at the bottom, start where we actually have widely-capable productive machinery, and scale our way down. McClellan’s motor had a radius of 195 microns. By odd coincidence, Drexler specifies a motor in Nanosystems with a radius of 195 nanometers (p. 339) — a neat factor of 1000. That’s just 5 of those factor-of-4 scaledowns. Over the two decades since 1989, that’s four years to do each scaledown.

Now that would be a tall order for a research team of, say, five people, however skilled, and a small lab, such as would need a million-dollar budget. Feynman said “rather a difficult program,” and he understood that you’d have to invent new techniques, use different physical phenomena, and so forth as you went down. But you’d have 1000 such teams! Who’s prepared to bet that we wouldn’t have at least a 50% chance of nanometer-scale mechanical engineering by now?

And if we didn’t, we’d certainly have a widely-capable industrial base of productive machinery at some intermediate scale. For example, if only 3 stages had been completed, motors would be smaller than a human cell, shafts less than a micron in diameter, and tolerances would be approaching atomic dimensions. But there would be lathes and milling machines and manipulators and robot arms all at that scale.

Such a technology would find a host of uses outside of the lab. But importantly, perhaps, when people asked us where was the nanotech we had promised, we could say, “We’re 60% of the way there.” This would be more than blowing smoke because we’d be proceeding along a pathway with a specific, measurable figure of merit (scale), and we’d require that in order to claim a given scale, someone would have to demonstrate a complete, closed-loop manufacturing base at that scale.

This isn’t by any means the only way to nanotechnology. What it is is a coherent program specifically directed at the goal of producing a widely-capable industrial base of productive machinery at the nanoscale. There are other pathways that make as much sense — including bottom-up approaches such as protein engineering. (On the other hand, it looks like we’re about to start tossing another couple of billion dollars a day at stimulus projects; and the whole state of Michigan seems to be full of laid-off engineers and machinists these days. Why not give it a try? What could it hurt?)

We’re probably not five full generations away from that general technological base. While we didn’t concentrate very well on the real goal for 20 years, we haven’t stood still either. Current macroscopic mechanical actuators have a precision of about half an angstrom. We know a lot of the meso- and nanoscale science (e.g. tribology) that would have had to be learned while building smaller and smaller machines.

So a top-down approach today could start closer to the finish line and be integrated into a lot of other new capabilities. But there has to be some actual plan for getting from A to B, some milestones or figures of merit that measure progress. Whatever the approach, there must be the fundamental understanding that the goal of a nanoscale industrial base is the priority, and that all achievements will be judged on that basis.

The major reason for unfulfilled promises, in my view, is simply that there really hasn’t been a plan at all. If nanotechnology is five generations out along any dimension, what we should be working on is the tools to make the tools to make the tools to make the tools. But that requires a coherent, committed effort with a well-defined long-term goal. And that in turn requires a vision of the goal: a widely-capable industrial base of productive machinery at the nanoscale.

Leave a comment

    Your Cart
    Your cart is emptyReturn to Shop