Automation is not the only influence upon the industries of the future, even though it is the major one that can now be measured because it is well underway. There are two other technological developments that may eventually play important roles, but both are in the very earliest stages, so detailed comments on their long-term effects are highly speculative.
On first consideration, it might seem unlikely that much manufacturing will ever be done off this planet, because of the great expense and logistical difficulties. However, there are products that may be worth the trouble. For instance, certain alloys are very difficult to mix homogeneously within Earth's gravitational field. The more massive constituents either form into globules or collect on one side of the molten mix, preventing the desired alloy from forming when the metals are re-solidified. Such mixtures may also have strength-robbing air bubbles because the metals do not completely lose all their gas during solidification. These problems do not occur in the zero gravity and vacuum of space, and there may well be alloys that are sufficiently valuable, say, for microelectronics or jewelry, to be worth manufacturing in Earth orbit.
Indeed, orbital environments are probably the best place to make alloys from which to build the space factories and habitats themselves, for the desired materials will have properties utterly unlike those required by Earthbound construction. Down here, a large building must support its own weight, and this is the first consideration in erecting its framework. In space, structural strength need only hold a building together against rotational forces; the materials need to combine strength with low mass, for they need not hold anything "up." Alloys that can do this and continue to perform well in a space environment are likely to be those made in the same environment.
There are obstacles, of course, to any such construction on a large scale. The main one is the expense and difficulty of supplying raw materials from the Earth below. However, once such manufacturing reached a certain scale, it could become economical to mine raw materials in the asteroid belt or on the moon. Transportation to Earth orbit from either location would be time consuming but relatively inexpensive. Or, manufacturing facilities could be located on the moon itself, where the vacuum is nearly as good as in orbit and gravity is only one-sixth that of Earth.
It is not clear whether the optimistic projections some make (of large numbers of people living in orbital habitat) are well founded though, even if substantial manufacturing were transferred there. After all, if Earth-based factories (and research or military establishments) would need few workers, the same would apply to those in space. For large communities to be built there, some other economic justification would have to be found, and it is not yet known what this could be.
Other substances whose manufacture might be easier in space include various chemicals, particularly pharmaceuticals. For very fine work involving precise reaction conditions and requiring fast and uniform mixing, zero gravity may be ideal. For example, if it turned out that a cure for some fatal disease could best be made in orbit, it surely would be.
Such work, however practical it may turn out to be in the long run, is still very experimental. Only when it becomes clear to entrepreneurs that there is money to be made by commercializing space will they rush to construct orbiting factories. One way to encourage this would be for the U.S. government to allow private companies to bid for the delivery of materials to Earth orbit, for such delivery can certainly be done for a much lower cost than it is at present. On the whole however, suggestions that a move of industry off planet will constitute a third industrial revolution (already underway) may be somewhat premature. Indeed, tourism might be a stronger motivation to make money from space than is manufacturing.
At the opposite end of the size scale from large space factories are the microscopic technologies of the silicon chip and the even smaller molecular-scale technologies. It is already possible to etch very small electronic features on glass, but even these are still hundreds of atoms wide. Yet living cells contain much smaller protein factories and assemblers that are capable of working atom by atom to build very specific molecules. It is, therefore, easy to wonder whether such assemblers can be made to order, like any machine, and directed to build the desired molecules by a chemist, engineer, or geneticist.
Eric Drexler (Engines of Creation) uses the term "nanotechnology" for work of this kind and observes that some success in the engineering of proteins has already been achieved. He sees the first generation of nanomachines as programmable and able to work like cellular organelles to build molecules into artifacts according to patterns coded into some auxiliary molecule acting like a "memory" enzyme. He terms such machines general purpose assemblers, for they could build a variety of molecules, not just proteins. In particular, they could make more robust, much smaller, and more specialized assemblers that could operate on atoms rather than on molecules.
These specialized assemblers would first have to build many more copies of themselves, or the quantity of the intended end product would not amount to much. Once this step was complete, they could in theory manufacture any amount of the target substance out of its atomic constituents--from houses to hot dogs to electronic circuits only one or two atoms wide. For example, carbon atoms could be laid down in the correct lattice to make diamond fibres that would give, say, engine parts great strength. Drexler envisions nanomachines that could even build entire rocket engines or computers in a fluid environment containing the raw elemental materials. Other potential nanotechnologies will be mentioned in later chapters.
The potential for large-scale manufacturing by such methods is difficult to assess. While it is true that only a few breakthroughs may be necessary to start on this route, it is not clear that nanomachines will necessarily be better or more efficient for large-scale work than ordinary machines. Assuming that they are developed, it seems more likely that such assemblers will be used principally for very fine work on speciality molecules and in chemical, genetic, and biological applications than on the making of consumer goods. At least, this is likely to be the case for some time until the technology matures.
However radical the changes that nanotechnology might bring therefore, they may not represent another industrial revolution but have their impact on society in other ways that are less direct. Some of these will also be touched upon in later Chapters.