Editing Self-replication (section)

==In industry==

===Space exploration and manufacturing===
The goal of self-replication in space systems is to exploit large amounts of matter with a low launch mass.  For example, an [[autotroph]]ic self-replicating machine could cover a moon or planet with solar cells, and beam the power to the Earth using microwaves.  Once in place, the same machinery that built itself could also produce raw materials or manufactured objects, including transportation systems to ship the products. [[Von Neumann Probe|Another model]] of self-replicating machine would copy itself through the galaxy and universe, sending information back.

In general, since these systems are autotrophic, they are the most difficult and complex known replicators.  They are also thought to be the most hazardous, because they do not require any inputs from human beings in order to reproduce.

A classic theoretical study of replicators in space is the 1980 [[NASA]] study of autotrophic clanking replicators, edited by [[Robert Freitas]].<ref>[[Wikisource:Advanced Automation for Space Missions]]</ref>

Much of the design study was concerned with a simple, flexible chemical system for processing lunar [[regolith]], and the differences between the ratio of elements needed by the replicator, and the ratios available in regolith.  The limiting element was [[Chlorine]], an essential element to process regolith for [[Aluminium]].  Chlorine is very rare in lunar regolith, and a substantially faster rate of reproduction could be assured by importing modest amounts.

The reference design specified small computer-controlled electric carts running on rails.  Each cart could have a simple hand or a small bull-dozer shovel, forming a basic [[robot]].

Power would be provided by a "canopy" of [[solar cell]]s supported on pillars.  The other machinery could run under the canopy.

A "[[casting]] [[robot]]" would use a robotic arm with a few sculpting tools to make [[plaster]] [[molding (process)|mold]]s.  Plaster molds are easy to make, and make precise parts with good surface finishes.  The robot would then cast most of the parts either from non-conductive molten rock ([[basalt]]) or purified metals.  An [[electricity|electric]] [[oven]] melted the materials.

A speculative, more complex "chip factory" was specified to produce the computer and electronic systems, but the designers also said that it might prove practical to ship the chips from Earth as if they were "vitamins".

===Molecular manufacturing===
{{Main|Molecular nanotechnology#Replicating nanorobots}}

[[Nanotechnology|Nanotechnologists]] in particular believe that their work will likely fail to reach a state of maturity until human beings design a self-replicating [[assembler (nanotechnology)|assembler]] of [[nanometer]] dimensions.[https://www.MolecularAssembler.com/KSRM/4.11.3.htm]

These systems are substantially simpler than autotrophic systems, because they are provided with purified feedstocks and energy.  They do not have to reproduce them. This distinction is at the root of some of the controversy about whether [[molecular manufacturing]] is possible or not.  Many authorities who find it impossible are clearly citing sources for complex autotrophic self-replicating systems.  Many of the authorities who find it possible are clearly citing sources for much simpler self-assembling systems, which have been demonstrated.  In the meantime, a [[Lego]]-built autonomous robot able to follow a pre-set track and assemble an exact copy of itself, starting from four externally provided components, was demonstrated experimentally in 2003.[https://www.MolecularAssembler.com/KSRM/3.23.4.htm]

Merely exploiting the replicative abilities of existing cells is insufficient, because of limitations in the process of [[protein biosynthesis]] {{Crossreference|(see also the listing for [[RNA]])}}.

What is required is the rational design of an entirely novel replicator with a much wider range of synthesis capabilities.

In 2011, New York University scientists have developed artificial structures that can self-replicate, a process that has the potential to yield new types of materials.  They have demonstrated that it is possible to replicate not just molecules like cellular DNA or RNA, but discrete structures that could in principle assume many different shapes, have many different functional features, and be associated with many different types of chemical species.<ref>{{cite journal | doi = 10.1038/nature10500 | last1 = Wang | first1 = Tong | last2 = Sha | first2 = Ruojie | last3 = Dreyfus | first3 = Rémi | last4 = Leunissen | first4 = Mirjam E. | last5 = Maass | first5 = Corinna | last6 = Pine | first6 = David J. | last7 = Chaikin | first7 = Paul M. | last8 = Seeman | first8 = Nadrian C. | year = 2011 | title = Self-replication of information-bearing nanoscale patterns | journal = Nature | volume = 478 | issue = 7368 | pages = 225–228 | pmid=21993758 | pmc=3192504| bibcode = 2011Natur.478..225W }}</ref><ref>{{cite web | url = https://www.sciencedaily.com/releases/2011/10/111012132651.htm | title = Self-replication process holds promise for production of new materials. | date = 17 October 2011 | website = Science Daily | access-date=17 October 2011}}</ref>

{{Crossreference|For a discussion of other chemical bases for hypothetical self-replicating systems, see [[alternative biochemistry]].}}