Advanced Automation for Space Missions/Chapter 5.1

Chapter 5: Replicating Systems Concepts: Self-Replicating Lunar Factory And Demonstration

5.1 Introduction

As the cost of fossil-fuel energy continues to escalate and supplies of readily accessible high-grade ores and minerals gradually become depleted, the utilization of nonterrestrial sources of energy and materials and the development of a nonterrestrial industrial capacity become increasingly desirable. The Moon offers plentiful supplies of important minerals and has a number of advantages for manufacturing which make it an attractive candidate factory site compared to Earth. Given the expense and danger associated with the use of human workers in such a remote location, the production environment of a lunar manufacturing facility should be automated to the highest degree feasible. The facility ought also to be flexible, so that its product stream is easily modified by remote control and requires a minimum of human tending. However, sooner or later the factory must exhaust local mineral resources and fall into disrepair or become obsolete or unsuitable for changing human requirements. This will necessitate either replacement or overhaul, again requiring the presence of human construction workers with the associated high costs and physical hazards of such work.

The Replicating Systems Concepts Team proposes that this cycle of repeated construction may possibly be largely eliminated by designing the factory as an automated, multiproduct, remotely controlled, reprogrammable Lunar Manufacturing Facility (LMF) capable of constructing duplicates of itself which would themselves be capable of further replication. Successive new systems need not be exact copies of the original, but could, by remote design and control, be improved, reorganized, or enlarged so as to reflect changing human requirements. A few of the benefits of a replicative growing lunar manufacturing facility (discussed at greater length in secs. 5.4 and 5.5) include:

1. The process of LMF design will lead to the development of highly sophisticated automated processing and assembly technologies. These could be used on Earth to further enhance human productivity and could lead to the emergence of novel forms of large-scale industrial organization and control.
2. The self-replicating LMF can augment global industrial production without adding to the burden on Earth's limited energy and natural resources.
3. An autonomous, growing LMF could, unaided, construct additional production machinery, thus increasing its own output capacity. By replicating, it enlarges these capabilities at an increasing rate since new production machinery as well as machines to make new machines can be constructed.
4. The initial LMF may be viewed as the first step in a demonstration-development scenario leading to an indefinite process of automated exploration and utilization of nonterrestrial resources. (See fig. 5.1.) Replicating factories should be able to achieve a very general manufacturing capability including such products as space probes, planetary landers, and transportable "seed" factories for siting on the surfaces of other worlds. A major benefit of replicating systems is that they will permit extensive exploration and utilization of space without straining Earth's resources.

Figure 5.1 - Automated space exploration and industrialization using self-replicating systems.

5.1.1 Summary of Chapter Contents

The history of the concept of machine replication is reviewed in section 5.2. This theoretical background is largely a consideration of the work of John von Neumann - in particular, his kinematic and cellular models of automata self-reproduction. Post-von Neumann research is reviewed next, noting particularly the established theoretical capabilities of machines in the realm of general construction, inspection, and repair strategies. Such strategies may prove useful, even vital, to the successful design, realization, and operation of actual replicating systems.

Section 5.3 deals with the engineering feasibility of the concept of self-replicating systems (SRS). An attempt is made to confront two important general problems in creating a lunar replicating factory:

• Given that in theory, machines can construct duplicates of themselves, how might systems designers and engineers identify all functions which must be carried out to achieve machine replication and also develop the technological means by which to implement these functions?
• Given the constraints obtaining in the lunar environment, particularly in terms of the inventory of known kinds and quantities of naturally occurring raw materials and the existing repertoire of materials processing technologies, can all machine functions required both for production and for replication and growth be implemented?

To attack the first of these problems - identification of necessary functions for practical machine replication - the team proposes a specific phased demonstration development scenario, described in section 5.3. For the second problem - establishing that machine replication can feasibly take place in the actual lunar environment - a strawman mission concept was employed. In this scenario, a 100-ton initial "seed" factory is planted on the Moon with access only to local resources and established materials processing techniques. The initial system should be able to successfully develop into an expanded machine system capable of conducting all functions necessary for autonomous replication, growth, and automated production and manufacturing.

The problem of "closure" is also considered at length in section 5.3. The issue of closure is whether autonomous manufacturing and construction systems can make available to themselves all of the materials, parts, and assembly techniques required for all internal operations. An iterative strategy is presented for detecting and eliminating closure gaps, and for optimizing the resulting augmented system.

Section 5.4 deals with possible applications of the SRS concept. Applications of replication technology include enormous gains in terrestrial industrial productivity (automation and computer-aided design and manufacturing), utilization of Solar System resources, orbital and planetary opportunities, and the possibility of interstellar exploration on a grand scale. Indefinitely large masses can be organized in extraterrestrial environments using self-replicating systems.

Section 5.5 deals with just a few of the many implications of SRS. The advantages of space-based replicator manufacturing are considered, together with possible political, social, economic, cultural, and psychological consequences of the proposed SRS development program.

Section 5.6 sets forth in some detail how NASA can take action at once toward the achievement of the ultimate goal of establishing a replicating manufacturing facility. Suggested statements of work (SOWs) and a listing of institutions that might undertake the tasks outlined in the work statements are included. A series of specific conclusions and recommendations generated by the Replicating Systems Concepts Team are presented in section 5.7.