A reader submitted a link to a new PhysOrg.com story on robotic self-reproduction. The article describes research done at Cornell on self-reproducing machines. The researchers have manually designed both real and virtual self-reproducing machines to demonstrate their feasibility. They are now starting to artificially evolve self-reproducing machines. The manually designed prototypes are called molecubes and look like 10 cm cubes that can swivel and connect to other cubes. The cube-based robots are able to assemble exact duplicates of themselves. The researchers believe the key to making this work is keeping the building blocks simple, just as evolution resulted in complex biological organisms built from a repertoire of only about 20 different amino acids. In addition to self-reproduction, these robots can reconfigure at will, a feature handy on long space missions where unforseen problems might require specialized robots. For all the details, see the paper released by the researchers, "Evolved and Designed Self-Reproducing Modular Robotics" (PDF format). We've also covered some of this research in our an article last year about resilient machines.