Dyson’s Terraforming Replicators
In 1970, physicist Freeman Dyson proposed a self-replicating habitat that allows the terraformation Mars into a suitable environment for human survival. It begins with the launch of a rocket that carries “a small but highly sophisticated payload” from the Earth to Enceladus, a satellite of Saturn. The payload contains an “automaton” capable of replicating itself using only the materials available on Encelaudus. And it used the Sun as its source of energy. In addition, the system is also programmed to manufacture “miniature solar sailboats.” By radiation pressure from sunlight, these solar sailboats would deliver large loads of ice to Mars, terraforming the surface of Mars.
Moore’s Artificial Living Plant
Following Von Nuemann’s abstract deductions on the logics of replication in the late 1940s and early 1950s, in 1956, mathematician and scientist Edward F. Moore proposed the first known practical real-replicating machine— the Artificial Living Plant. According to Moore, the Artificial Living Plant “makes copies of itself not from artificial parts in a stock room but from materials in nature.” Similar to an organic living plant, the Artificial Living Plant extracts from the air, water and soil; it obtains energy from the sunlight by solar battery or steam engine. Using its solar power, the Artificial Living Plant can draw from raw materials and make them into parts. It then assembles the manufacture parts to make more copies of itself. Moore selects the seashore as a suitable habitat for the Artificial Living Plant, providing it with easy access to various useful elements and minerals from the sea and the beach. He also imagines designing similar Artificial Living Plants that grows in the ocean surface and desert regions. The “plant” could be harvested for material it synthesized and used as a commodity. Moore points out the advantageous ability of such self-replicating machine to multiply exponentially, as opposed to automatic factories that can only manufacture specific products at a constant rate.
Like Moore’s Artificial Living Plant, my preliminary proposal is also biologically inspired. (whale cyborg) As Merkle points out, “living biological systems are wonderfully flexible.” It has the capability to cope with complex environments. Mechanical systems, on the other hand, are limited to perform under controlled conditions. Moreover, organic living systems often have diverse sources of energy. Using Merkle’s analogy: horses, for instance, can obtain energy from potatoes, corn, sugar, hay, straw, etc; while cars; on the other hand, can only be powered by gasoline, generally. (It has other sources, i.e. solar, electricity, but very limited) There is no doubt that the means to obtaining energy source will become a great concern of ours in the near future. Having various means to extract energy would definitely serve to the system’s advantage.
But there is a trade-off to the system’s flexibility and adaptability: the system would be much more complex and hence extremely difficult to design. Like Merkle said, “it’s difficult enough to design a system able to self replicate in a controlled environment, let alone designing one that can approach the marvelous adaptability that hundreds of millions of years of evolution have give to living system.”
Hence, unlike Moore’s design, my design would try to retain the flexibility and adaptability of living organisms by incorporating mechanical parts to an existing living thing, rather than creating a mechanical system that resembles it.
Reference
Kinematic Self-Replicating Machines, Robert A. Freitas Jr. and Ralph C. Merkle
Self-replication and Nanotechnology http://www.zyvex.com/nanotech/selfRep.html??