2.0 - Concept History and Development
In this section we begin looking in more detail at self-expanding systems in general, and the seed factory concept in particular. Growth and replication as natural processes have a long history, so we look at those first. Next we look at these processes in human culture, followed by where the component ideas for the current seed factory concept originate. In Section 2.1: Technology Development we look at the current state-of-the-art, in terms of already existing technology, the current status of seed factory ideas, and projects to implement such systems or parts of them. From the current status we can then identify areas which need more research and development, and a plan for developing such needed technology.
Expansion, growth, and replication are natural processes which existed long before humans were around to think about them. Human artifacts like factories can make use of and adapt these processes to modern needs.
Expansion as a process appears to be as old as the Universe itself. Red-shifts of spectra from distant galaxies, distant supernovae brightness and light curves, and the Cosmic Microwave Background Radiation imply that space itself is expanding. This seems to be the combined effect of strong repulsive forces from Cosmic Inflation during the Big Bang ~13.8 billion years ago, and Dark Energy, which continues to accelerate the expansion. If the inflation theory of cosmology is correct, the growth of large scale structures, now hundreds of millions of light years in size, can be traced to quantum fluctuations during the inflationary era. Galaxies, black holes, and stars grow by Accretion, the addition of more matter to what is already there. Since the force of gravity is linear with mass, the ability to attract more matter is proportional to the mass already collected. This results in an exponential growth process, until all the nearby matter is consumed. Any growth process which is proportional to the current size leads to exponential increases over time, and we will see many examples of this kind growth in the course of the book.
Stars replicate in a limited sense. As faster-aging large stars reach the end of their life, they emit large amounts of gas or explode. The shock waves from these processes can create high density areas in molecular clouds. These denser areas can collapse to form a new generation of stars. Our own Sun is thought to be a third generation star whose formation may have been caused by a supernova explosion of a nearby older star. Planets also form by a process of exponential growth from smaller bodies. A growing planet has a larger gravitational field, so it can attract more gas, dust, and other small bodies to itself. It is not evident how astronomical processes could be used in current factory design, but we can incorporate the concepts of expansion, replication, and exponential growth.
It's estimated that life began on Earth about 3.8-4.1 billion years ago, in the first 20% of the age of the planet. Growth and reproduction are two of the defining features of Life. Another defining feature of life is metabolism, the use of available energy to convert raw materials into parts of the organism. Most of the energy for life ultimately comes from the Sun, and living things incorporate local materials (food) into themselves. Waste products and dead organisms are recycled by other organisms, and along with nonliving parts of the environment form an Ecosystem of related elements. We can also incorporate these ideas of energy and material sources, recycling, and an ecosystem of related elements into our designs.
Small organisms like bacteria and algae consist of a single cell which divides repeatedly. Large organisms like whales and trees consist of many cells, which individually divide, then become specialized for different tasks and grouped into larger structures. In addition, large organisms can incorporate non-living matter, like the mineral parts of bones or the wood and bark of trees. The replication of a large organism involves partitioning one or a small number of cells into an Embryo or Seed, a smaller and simpler entity than the mature organism. This entity contains all the information to build the mature organism, in the form of long double-chain polymer molecules known as DNA (Deoxyribonucleic Acid), usually after mixing genetic data from two parents. The initial cells then divide and specialize until they become a mature copy of the parent organism. Humans, being large organisms, grow and replicate in this way, both at the cellular and whole organism level. The process of growth from an embryo or seed is at least 400 million years old.
We can also incorporate the ideas of specialization during growth, replication via a smaller and simpler starter entity (i.e. a seed), and replication of information into our designs. Because so many features from biology can be included into a self-expanding factory, we can consider it a form of Artificial Life.
In Human Culture
The natural processes of expansion and replication noted above long predate modern humans, who have only existed for about 200,000 years. As living beings we continue to participate in these processes, and they continue to operate in nature. In addition, humans produce Culture, which are entities that persist beyond the death of individual people. Human culture also displays growth and replication processes.
- Cultural Elements
Culture includes both non-material elements, and Material Culture. Non-material culture includes things like patterns and knowledge. For example, an early Hunter-Gatherer band could persist as a pattern for a much longer time than any member lived. Language and how to use it is knowledge that can be passed down through many generations orally, without ever being written down. Material culture, like tools and cities, if maintained, can also last well past the life of any individual. The life span of an artifact, however, does not determine if it is cultural. The important feature is whether it exists independent of human biology. For example, a fast food soft drink cup may only be used for a few minutes, or sit on a shelf for years, but our internal biology does not affect these lifetimes.
All kinds of cultural elements can exhibit growth and replication. A hunter-gatherer band can grow to the point it divides into two bands. A language can grow by the addition of new words, and by new people adopting it. New languages can form when people live far enough from each other that they rarely communicate. Shifts in vocabulary and usage then lead to enough changes that there are two distinct languages instead of one. Widespread distribution of media like books and video have tended to stabilize language content, and worldwide communications means nobody is too far away any more. Although the trend is now for small languages to disappear in favor of the more commonly used ones, the remaining ones continue to grow by adding new words and speakers. Cities can grow by physical additions to an existing city, and historically reproduced by setting up colonies in new locations.
The oldest elements of culture that showed growth and replication probably predate modern humans themselves. They include Band Society, and early types of technology in the form of hunting, foraging, and tool-making skills. Species of the the genus Homo, of which modern humans are the only surviving member, expanded repeatedly across the world over the past few million years. Successful social groups therefore presumably divided when their population became larger than a given area could support. Skills could grow by accumulation of details and technique and by specialization. Since each person has a limited memory and time to learn, specialization allows more total skills to be passed on. Cultural replication included making new copies of tools from raw materials, but not generally using existing tools to copy themselves. So it was a parallel process of replication among a collection of tools.
In a broad sense, Technology includes all the knowledge, skills, and artifacts used towards practical ends. So a tool like a hammer is a technological artifact, but knowing how to make and use hammers is also part of "hammer technology". The oldest technologies of all are foraging and nest building using nothing more than hands. Other species of Great Apes do this, and presumably so did our hominid ancestors millions of years ago. We can speculate about using sticks and rocks to knock down fruit or kill prey, but those kinds of tools don't leave lasting evidence of their existence. The oldest identifiable tools are split and flaked stones from Kenya that are 3.3 million years old. These types of tools were not used to make more tools of the same kind. If you wanted to copy them, you needed to start fresh with new rocks. The skills and knowledge, however, could be copied by observation and imitation, even if language did not exist yet. The original stone tools could be used to make secondary tools. For example hand choppers and scrapers made from split rocks can be used to cut and peel branches, which can then be used as clubs, or handles for stone axes.
The earliest use of tools to make more tools may date from using Digging Sticks and Hammerstones to excavate and flake stones, which in turn can cut and sharpen more digging sticks. Over time, hand tools such as these started to be used to make better tools and artifacts, a process which still continues today. Eventually, specialized groups of toolmakers developed, such as blacksmiths, who were able to copy their own tools plus make tools for other trades. We can make a distinction between those who can make their own tools and those who use tools made by others. Other kinds of tools and machines elsewhere in civilization can trace their existence to the self-making toolmakers. Early blacksmiths could replicate tools, but they were not mechanized and certainly not automated. Animal, water, and wind power later augmented human muscles and allowed larger and faster production. The specialized modern descendants of blacksmiths, such as steel mills, foundries, and machine shops, retain the collective ability to make more tools and machines of the type they themselves are made. As a group they are thus able to replicate.
Agriculture is the part of technology concerned with purposely growing living things. That living things can grow and make copies of themselves from seeds or by giving birth was evident to people at least as long as agriculture has been in use, which is about 12,000 years, and was probably known before that. Understanding the detailed mechanisms only began a few hundred years ago, including replication of DNA, division of cells, and all the supporting biochemical machinery. Biological seeds usually contain the plant embryo, which does the actual growing, a supply of nutrients to support the initial growth, and a protective coating. But long before understanding the details of how they worked, people knew seeds grew into full sized plants, which in turn produced more seeds. This cycle is known as Indirect Replication.
Because each plant generally produces many seeds, their number can grow exponentially until they are limited by competition or available resources. So any natural landscape which can support them tends to be covered in plants. Once people learned to exploit the supply of nutrients in plants and animals, and started raising them intentionally, their natural ability to grow exponentially increased the human food supply dramatically. In turn, human population also grew exponentially. The inventiveness per person of modern humans has probably not changed much in the past 200,000 years. But with vastly more people today, and better ways to pass on knowledge, the accumulation of new knowledge and culture has also grown exponentially.
- Starter Sets
Starter sets have occurred throughout human history, especially when settling new areas. At first, these were a hand-carried set of tools to be used in a new location to hunt, chop, and grind. Once more complex levels of technology had developed, colonizing a new location via ship or land travel included bringing along a starter set of plant seeds, animals, tools, and an inventory of finished items like nails, which could not be made immediately. Once they arrived, people set about clearing, planting, and building, eventually reaching the point they could make their own tools. Until then, they traded with their original location for items they could not yet make. The contents of the starter set has varied by era, but it was well understood that you needed one to survive and flourish in a new location. In the modern world, the idea of starting fresh at a new location has become less common. Improved transportation and cheap mass production are used instead to deliver finished items when needed. An idea can still be sound, though, even if it is not currently popular. We can update the basic idea of a starter set to incorporate 21st century equipment, along with additional ideas and methods. This can make it a relevant choice again, especially in more difficult and remote locations.
Workshop builders are accustomed to upgrading the shop by building storage, workbenches, jigs, and other extensions using their starter set of tools and machines. Sometimes wood and metal shops will build complete new machines using the ones they already have, but they typically do not produce all of their own parts. Normally they make the easier items, and buy things like bearings and motors which are harder to make. So far as we know, no one has yet designed and operated a shop or factory which intentionally uses a starter set, makes most or all of the items for expansion, and uses high levels of automation.
At first, all work was performed entirely by human muscle. Once work animals were domesticated they supplemented our muscles with theirs. Mechanization refers to the replacement of hand tools and human muscles with machines using other power sources. Mechanization extends back to ancient times in particular cultures and for particular tasks, but only became widespread since the Industrial Revolution, starting around 1760. Where mechanization replaces muscles, Automation and Robotics further replaces the decision-making, senses, and flexible arms and legs of people with electrical, electronic, and mechanical systems. This reduces the need for constant human attention to work tasks. By the mid-20th century, electronics had developed to the point they could be programmed and used as sensors, and the field of Control Theory was well enough understood to design self-operating systems that used these electronic devices. Automation and robotics started to be developed on a large scale from that time.
Machines in general involve movement, but often the type of movement is fixed by design. Robots are machines which can perform movement under automated or remote control, where the specific movements are not pre-designed. So a robot can change the task it is doing by changing the control inputs. Robotics has developed in parallel with more fixed types of automation. By now (2017) automation and robotics is extensively used in factories, and is starting to be used in other environments. In the past, people used tools and machines to make more tools and machines. The development of automation and robotics means the machines are becoming more able to do so on their own, without needing people to do much of the work.
We can extract a number of these ideas and processes from nature and human culture, plus a few new ones, and combine them into a new type of self-expanding and upgrading production system. Since purposely designed starter sets which evolve to larger and more complex systems is the key idea, we refer to the whole collection as "Seed Factory" technology, but it includes more than just that feature. The more important ones that have been included under the current Seed Factory umbrella are:
Replication in the general sense has always existed in biology. In technology we often make identical copies of products, but Machine Replication, or "self-replicating machines", as a term is reserved for machines or factories which make complete copies of themselves. The idea of machine replication was evident as soon as control theory and automation became practical. It got serious theoretical study in the same period, the mid-20th century, starting with work on Reproducing Cellular Automata by John Von Neumann. A 2004 book by Freitas and Merkle, Kinematic Self-Replicating Machines thoroughly reviews the literature for replicating systems to that point.
A 1982 NASA report, Advanced Automation for Space Missions (AASM), introduced the concept of a replicating factory for use on the Moon (Figure 2.1). Their approach was to make copies of the original factory hardware, with an unspecified end product once enough copies had been made. The AASM study introduced the term Seed Factory to mean the first unit of the factory delivered from Earth to the Moon. In this Wikibook we use the name for a more general concept of a starter set which can expand by multiple methods besides direct copies of itself.
Due to inadequate communications bandwidth from Earth at that time, the AASM concept of a Lunar factory needed to be fully automated. The resulting computer requirements, estimated at 2 GB memory and 35 GB storage, were far beyond what was available at the time of the study (1980). The Seed Factory was also assumed to be delivered as a complete functioning unit to the Moon, with an estimated mass of 100 tons. This was beyond the delivery capacity of any lander at the time, and still is today. There was also no pressing need to build things on the Moon. For these reasons the concept was not developed further. The study considered availability of raw materials, and processing methods, but did not do a full resource flow accounting of all materials, energy, and data. It also neglected to consider Earth applications of the idea, because NASA's primary goals do not include improving Earth manufacturing. This is probably still the best engineering study to date of a fully replicating factory. This is despite the technology of the time not being up to the task, and the various study deficiencies.
The AASM study assumed full replication of a starter factory. It did not consider starting with a simpler subset and adding new equipment over time. Requiring full replication from the start makes the initial hardware both more complicated to design, and physically larger. Even if you were able to make all the parts to replicate, from an engineering standpoint it might not make sense. It is likely that a given location will not have certain rare raw materials. In the case of the Moon, a 1986 study of building solar power satellites found 98% could be sourced from there, but the other 2% had to come from Earth. It is also likely that some parts, like computer chips, are very difficult to make yourself, compared to simply buying them. Therefore a practical design will most likely fall short of 100% replication. Given that some materials and parts will be imported in an optimized design, it is then a small conceptual step to allow the percentage of imported items to vary by time.
A small starter set is able to make some of the parts for new and different equipment, and the balance has to be imported. Once you have added the new equipment, you can now make a wider range of parts, and therefore make parts for an even wider range of equipment. This Diversification continues until you you can make the full range of desired products, or reach the full set of equipment which are practical to use. When a factory reaches these full capacities we call it Mature. Compared to a factory which has the full set of equipment at the start, you replace it with a smaller set of equipment, plus a set of design files for the rest. With modern data storage, it costs nearly nothing to hold a large set of files. The seed factory with a subset of equipment is therefore less expensive to build. The fully expanded factory may end up larger and more capable than what is required for Practical Replication, i.e. the ability to copy all the parts that are practical to make internally. This happens if certain production processes or materials are not needed for replication, but are used for other end products. So the range of equipment can start well below being able to replicate and grow to a point well above it.
Categories of new equipment include extensions or attachments for existing equipment. For example, extension rails or a larger bed would allow a CNC mill to make larger parts. Conventional farm tractors are examples of machines which can be used with a multitude of different attachments. A modular vehicle chassis built for factory use could also accept a range of attachments, as could a basic robot arm. Items like assembly jigs, holding fixtures, molds, and custom cutting bits can make a basic machine more flexible. One criterion for choosing a member of the starter set is then how many extensions you can apply to it and thus how many different tasks it potentially can do. We call this feature Flexibility. The more flexible the starter machines are, the fewer you need for a useful set of them.
A simplified starter set is one way to reduce the complexity and cost of starting up a new factory. Scaling of machine sizes is another way to reduce cost, and was not considered in the AASM study. It should be evident that machines of a given size can make parts for larger machines, else our civilization would never have been able to make the larger machines that now exist, like 400 meter long cargo ships. One method to make larger items is by assembling them from smaller pieces, such as by welding or bolting. A prominent example is large buildings, which are typically make from a multitude of smaller parts. Another method is to use machines which are open-ended in at least one axis. An example is a rolling mill to make steel shapes. The rolling process does not limit the length of the metal parts you feed through it. It is only limited by how much room you have on either side.
In concept, you can start with whatever size machines are convenient. You can use these machines to make parts for larger machines of the same type, or for larger machines of new types. In turn, the second generation machines are used to make parts for even larger machines, until you reach whatever final size you wanted. In theory you could start with microscopic machines, but for practical reasons there is some lower bound to start from. More generations of scaling requires more time, and some redesign since not all parts of a system scale equally. Whatever operations and maintenance are not yet automated, and so require human interaction, need to be at a scale we can iwork with. Finally, the design effort for the number of machines in a factory is relatively constant no matter what size they are. So the savings in materials from starting smaller will eventually become negligible relative to the total design cost.
- Automation Level
The final assumption made by the AASM study was full automation. This was because with 1980 communications it was not possible to remote control even one factory on the Moon, let alone 1000 copies. We don't need to make that assumption for our seed factory concept. For one thing, certain tasks are either too hard to automate at present, or are done so rarely it is not worth trying to automate them. For another, trying to automate everything at the start requires more equipment and more design work. Lastly, modern communications has improved enough that remote control is quite possible over long distances. Instead of assuming full automation, we instead assume you start with whatever is a practical level. CNC machine tools and 3D printers are examples of existing equipment that are automated, so we would likely use them. Over time you can add things like robots and automated inventory systems to increase the amount of automation in the factory. Since you are able to partly make your own equipment, adding these later will be less expensive than trying to buy it all at the start. You can also defer the design work of the more complex automation until later.