Launch costs represent a fundamental limitation in accessing the space environment from the Earth's surface. However, several new trends are pointing towards a mechanism for sidestepping launch costs -Advances in robotics, the advent of in-situ resource utilisation, and developments in 3D printing techniques. Together, these technologies provide a means to extract raw materials from extraterrestrial sources and manufacture useful products. Rather than restricting such products to raw consumables as proposed for human missions, we envisage the extraction of many useful materials that can be further fashioned - glass from sintered lunar regolith, iron alloys derived from lunar ilmenite and nickel-iron bolides, silicone plastics and oils from lunar volatiles, etc. Enter 3D printing - it is well established that 3D printing can fabricate an infinitude of structures and mechanical components. The focus of our work is using the lunar feedstock (or rather analogue materials thereof) to fabricate actuators using 3D printing technology. We have successfully 3D printed aspects of electric motors including motor cores as the fundamental unit of a motor. This activity will be presented. Furthermore, using the same materials inventory as our motors, it maybe possible (TBD) to fabricate vacuum tubes. We have been characterising analogue-based neural network circuits to implement a novel computational architecture. Such circuitry could be implemented in vacuum tube technology. Ultimately, our goal is to prove that within a restricted materials inventory from the Moon, we can manufacture both motorised mechanisms and computational electronics through 3D printing technology, i.e., we would be able to 3D print robotic devices such as manipulators, rovers, drills, motorised machine tools, etc. The same basic components also provide the basis for energy generation (thermionic conversion in vacuum tubes) and storage (motorised flywheels). We would thus have the basic components to construct a spacecraft - we are currently exploring a research programme to 3D print an entire cubesat with a neural onboard data handling system and active three-wheel stabilised attitude control powered through solar concentrators-Thermionic converters. Inspired by the RepRap 3D printer which could print its own plastic structural components, we submit that this activity takes us much closer to the possibility of implementing self-replicating machines on the Moon capable of exponentially growing productive capacity in-situ. Such self-replication technology would revolutionise space exploration.

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Keywords Fusion, Magnetic confinement, Nuclear electric propulsion, Technology roadmap
Journal JBIS - Journal of the British Interplanetary Society
Ellery, A. (2017). Extraterrestrial 3D printing & in-situ resource utilisation to sidestep launch costs. JBIS - Journal of the British Interplanetary Society (Vol. 70, pp. 337–343).