Self-replication is the ability of a machine to reproduce all parts it consists of. In a more strict sense it stands for the capability to create a fully functional copy of itself, explicitly including the final assembly.
The interest of this concept on the one hand lies in the possibility of conducting long-term space missions, on the other hand there are strong economic implications: A machine capable of reproducing itself is consequently also able to manufacture a broad range of products.
The technique that comes closest to self-replication today is rapid prototyping. The term refers to processes which can automatically produce arbitrary three-dimensional forms without need for specially assembled machine parts. As the name implies it was originally used to produce parts used in prototypes. Today rapid prototyping is also applied for quick production of small series of parts. Until now, only plastic materials can be assembled with this degree of freedom.
RepRap is an effort to develop a self-replicating, cheap rapid prototyping machine whose construction is available free under the GNU license. Version 1 is finished and capable of producing free-form plastic parts, notably all non-standard parts that are required for its own construction. Version 2 is already in development; it is planned to be capable of producing simple electrical circuits (in addition to plastic parts).
The vision of the RepRap project is to enable everyone to produce all technical goods that they want by just “printing” out their digital construction plans. Chris DiBona, Google’s open source program manager, gave the following metapher:
Think of RepRap as a China on your desktop.
A fully functional self-replicating 3D printer would render useless much of our present production industry.
Then there is NASA who investigates concepts for self-replicating factories. On moon they could harvest and process materials to maintain a permanent lunar base. On a long scale, nano technology might enable to fabricate more and more small objects until the atomic scale is reached: then principally every object could be replicated.
Self-replication combined with nano-technology if out of control could be a serious threat. Just suppose that a nano-scale self-replicating mechanism is able to disassemble all sorts of matter in order to use it for production. If it then would be programmed to replicate just itself, like a hardware-virus, it could spread and “eat” all matter in its range.
Self-replication is still a concept, but one that might have the power to spawn a new industrial revolution, surpassing traditional production facilities and giving means of production to everyone. An amazing idea I think. Let’s see when/if it comes to be real. Until then you can replicate your own lego bricks.