As reported in Smalltimes, a study done for NASA's Institute for Advanced Concepts by General Dynamics Advanced Information Systems concludes that a useful self-replicating machine could be less complex than a Pentium IV chip, and uncovered no road blocks to extending macroscale systems to microscale and then to nanoscale self-replicating systems. The study also evaluated adherence to the Foresight Guidelines on Molecular Nanotechnology. The final report for the study can be downloaded from NASA as a PDF file.

The Principal Investigator for the study was Tihamer Toth-Fejel, with consultants Robert Freitas and Matt Moses. Their abstract:

General Dynamics Advanced Information Systems has completed preliminary design and modeling studies for the design of a useful Self-Replicating System (SRS). As shown by NASA?s summer study Advanced Automation for Space Missions and other smaller studies, the development of SRSs that constitutes a Universal Constructor (UC) could revolutionize future space missions. Using solar power and in situ resources, a self-replicating lunar factory could build solar cells and other manufactured tools with which to explore and develop the Moon and other extraterrestrial environments with limited exponential growth. But despite the fact that these studies showed the tremendous power of machine self-replication, there have been no large-scale attempts to advance the technology to even the demonstration stage. Before this (2003-2004) NIAC funding cycle, only two small efforts have ever resulted in any non-trivial success in the physical world. Both of the designs lacked significant functionality compared to an autonomous lunar factory, but they proved that machine self-replication is possible. The next step is to make self-replicating machines useful.

This report describes the progress made in that direction, specifically the design of a system of Kinematic Cellular Automata (KCA) cells that are configured as a limited implementation of a Universal Constructor.

Trivial self-replication is not difficult, but a final goal of autonomous and autotrophic self-replication is certain to be extremely difficult (and possibly not desirable). There is a large unexplored area between these two extremes that could still be characterized, but this project advanced our knowledge enough to complete a preliminary design of a physical KCA SRS.

With the advent of nanotechnology, "self-replication is widely viewed as the key to an entirely new industrial era that may one day replace modern microelectronic systems." In addition, self-replicating nanotechnology would reduce the price of complex manufactured goods to that of agricultural products.

Given such potential, it is incredible that half a century after John Von Neumann's seminal work, and 23 years after NASA's summer study, we do not have a single useful SRS. Even worse, we had little idea of the how to quantify the difficulty of useful machine self-replication – until this project attempted to answer that question.

The answer was surprising: The complexity of a useful KCA SRS is less than that of a Pentium IV.

Among the investigators' conclusions:

The expectation at the beginning of this project was that there would be difficulties in designing a KCA SRS … but the important and surprising result was that a small project of this scope could find a fairly clear and successful design with no roadblocks! …

The next logical step would be to build microscale KCA systems made with standard MEMS techniques. …

After that, the final stage of KCA SRS research will be to refine the concept to take advantage of nanoscale parts available at that time.

The Smalltimes story emphasized the attention paid to safety in the design study.

The study also examined machine designs that would meet guidelines established by the California-based nanotech think-tank Foresight Institute to ensure the safety of self-replication techniques. The preliminary study is believed to be among the first U.S.-sponsored studies on self-replication in two decades.

"While self-replication is not necessary for achieving the goal of molecular manufacturing, it's good to see that these NASA-funded system designs are in compliance with the Foresight Guidelines safety recommendations," said Christine Peterson, president of the Foresight Institute.