ENGINES OF CONSTRUCTION

(Chapter 1)
Two Styles Of Technology
Molecular Technology Today
Existing Protein Machines
Designing With Protein
Second-Generation Nanotechnology
Universal Assemblers
Nailing Down Conclusions
Nanocomputers
Disassemblers
The World Made New
References for Chapter 1

Universal Assemblers

These second-generation nanomachines - built of more than just proteins - will do all that proteins can do, and more. In particular, some will serve as improved devices for assembling molecular structures. Able to tolerate acid or vacuum, freezing or baking, depending on design, enzyme-like second-generation machines will be able to use as "tools" almost any of the reactive molecules used by chemists - but they will wield them with the precision of programmed machines. They will be able to bond atoms together in virtually any stable pattern, adding a few at a time to the surface of a workpiece until a complex structure is complete. Think of such nanomachines as assemblers.

Because assemblers will let us place atoms in almost any reasonable arrangement (as discussed in the Notes), they will let us build almost anything that the laws of nature allow to exist. In particular, they will let us build almost anything we can design - including more assemblers. The consequences of this will be profound, because our crude tools have let us explore only a small part of the range of possibilities that natural law permits. Assemblers will open a world of new technologies.

Advances in the technologies of medicine, space, computation, and production - and warfare - all depend on our ability to arrange atoms. With assemblers, we will be able to remake our world or destroy it. So at this point it seems wise to step back and look at the prospect as clearly as we can, so we can be sure that assemblers and nanotechnology are not a mere futurological mirage.

Nanocomputers

Assemblers will bring one breakthrough of obvious and basic importance: engineers will use them to shrink the size and cost of computer circuits and speed their operation by enormous factors.

Disassemblers

Molecular computers will control molecular assemblers, providing the swift flow of instructions needed to direct the placement of vast numbers of atoms. Nanocomputers with molecular memory devices will also store data generated by a process that is the opposite of assembly.

Assemblers will help engineers synthesize things; their relatives, disassemblers, will help scientists and engineers analyze things. The case for assemblers rests on the ability of enzymes and chemical reactions to form bonds, and of machines to control the process. The case for disassemblers rests on the ability of enzymes and chemical reactions to break bonds, and of machines to control the process. Enzymes, acids, oxidizers, alkali metals, ions, and reactive groups of atoms called free radicals - all can break bonds and remove groups of atoms. Because nothing is absolutely immune to corrosion, it seems that molecular tools will be able to take anything apart, a few atoms at a time. What is more, a nanomachine could (at need or convenience) apply mechanical force as well, in effect prying groups of atoms free.

A nanomachine able to do this, while recording what it removes layer by layer, is a disassembler. Assemblers, disassemblers, and nanocomputers will work together. For example, a nanocomputer system will be able to direct the disassembly of an object, record its structure, and then direct the assembly of perfect copies, And this gives some hint of the power of nanotechnology.

Machines able to grasp and position individual atoms will be able to build almost anything by bonding the right atoms together in the right patterns

Imagine this approach being used to "grow" a large rocket engine, working inside a vat in an industrial plant.
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At the center of the base plate, deep in the swirling, assembler-laden fluid, sits a "seed." It contains a nanocomputer with stored engine plans, and its surface sports patches to which assemblers stick.
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Where great strength is needed, the assemblers set to work constructing rods of interlocked fibers of carbon, in its diamond form.
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Its creation has required less than a day and almost no human attention.
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What is the engine like? Rather than being a massive piece of welded and bolted metal, it is a seamless thing, gemlike.

Imagine that you are aboard a space station, spun to simulate Earth's normal gravity. After instruction, you have been given a suit to try out: there it hangs on the wall, a gray, rubbery-looking thing with a transparent helmet. You take it down, heft its substantial weight, strip, and step in through the open seam on the front.

The suit feels softer than the softest rubber, but has a slick inner surface. It slips on easily and the seam seals at a touch. It provides a skintight covering like a thin leather glove around your fingers, thickening as it runs up your arm to become as thick as your hand in the region around your torso. Behind your shoulders, scarcely noticeable, is a small backpack. Around your head, almost invisible, is the helmet. Below your neck the suits inner surface hugs your skin with a light, uniform touch that soon becomes almost imperceptible.

You stand up and walk around, experimenting. You bounce on your toes and feel no extra weight from the suit. You bend and stretch and feel no restraint, no wrinkling, no pressure points. When you rub your fingers together they feel sensitive, as if bare - but somehow slightly thicker. As you breathe, the air tastes clean and fresh. In fact, you feel that you could forget that you are wearing a suit at all. What is more, you feel just as comfortable when you step out into the vacuum of space.

The suit manages to do all this and more by means of complex activity within a structure having a texture almost as intricate as that of living tissue. A glove finger a millimeter thick has room for a thousand micron-thick layers of active nanomachinery and nanoelectronics. A fingertip-sized patch has room for a billion mechanical nanocomputers, with 99.9 percent of the volume left over for other components.

In particular, this leaves room for an active structure. The middle layer of the suit material holds a three-dimensional weave of diamond-based fibers acting much like artificial muscle, but able to push as well as pull (as discussed in the Notes). These fibers take up much of the volume and make the suit material as strong as steel. Powered by microscopic electric motors and controlled by nanocomputers, they give the suit material its supple strength, making it stretch, contract, and bend as needed. When the suit felt soft earlier, this was because it had been programmed to act soft. The suit has no difficulty holding its shape in a vacuum; it has strength enough to avoid blowing up like a balloon. Likewise, it has no difficulty supporting its own weight and moving to match your motions, quickly, smoothly, and without resistance. This is one reason why it almost seems not to be there at all.

Your fingers feel almost bare because you feel the texture of what you touch. This happens because pressure sensors cover the suit's surface and active structure covers its lining: the glove feels the shape of whatever you touch - and the detailed pattern of pressure it exerts - and transmits the same texture pattern to your skin. It also reverses the process, transmitting to the outside the detailed pattern of forces exerted by your skin on the inside of the glove. Thus the glove pretends that it isn't there, and your skin feels almost bare.

The suit has the strength of steel and the flexibility of your own body. If you reset the suit's controls, the suit continues to match your motions, but with a difference. Instead of simply transmitting the forces you exert, it amplifies them by a factor of ten. Likewise, when something brushes against you, the suit now transmits only a tenth of the force to the inside. You are now ready for a wrestling match with a gorilla.

The fresh air you breathe may not seem surprising; the backpack includes a supply of air and other consumables. Yet after a few days outside in the sunlight, your air will not run out: like a plant, the suit absorbs sunlight and the carbon dioxide you exhale, producing fresh oxygen. Also like a plant (or a whole ecosystem), it breaks down other wastes into simple molecules and reassembles them into the molecular patterns of fresh, wholesome food. In fact, the suit will keep you comfortable, breathing, and well fed almost anywhere in the inner solar system.

What is more, the suit is durable. It can tolerate the failure of numerous nanomachines because it has so many others to take over the load. The space between the active fibers leaves room enough for assemblers and disassemblers to move about and repair damaged devices. The suit repairs itself as fast as it wears out.

Within the bounds of the possible, the suit could have many other features. A speck of material smaller than a pinhead could hold the text of every book ever published, for display on a fold-out screen. Another speck could be a "seed" containing the blueprints for a range of devices greater than the total the human race has yet built, along with replicating assemblers able to make any or all of them.

What is more, fast technical AI systems like those described in the last chapter could design the suit in a morning and have it built by afternoon.

Here's a short list of the powers you'd have or appear to have if embedded in fog:

Creation--causing objects to appear and disappear on command.
Levitation--causing objects to hover and fly around.
Manipulation--causing forces (squeezing, hitting, pulling) on objects (real ones) at a distance.
Teleportation--nearly any combination of telepresence and virtual reality between fog-filled locations