Building physical self-replicating machines
This paper introduces the concept of a physical self-replicating machine for deployment on the Moon utilizing raw material available on the Moon. A detailed but selective review is given in order to highlight clearly the novel aspects of this concept. In particular, it is hypothesized that if electric motors and vacuum tubes can be 3D printed from the limited repertoire of lunar materials, 3D printing constitutes a universal construction mechanism. This follows from the observation that mechatronic components are the constituent parts of all robotic mechanisms. In particular, we examine the use of 3D printing of electronics as a physical instantiation of a Turing machine. Several general implications of such a self-replicator are considered including whether it constitutes artificial life and mitigation against runaway replication.