An artist's rendering of what the 3D-printed lunar base could look like. (Photo : Foster + Partners)
Colonizing space could be far simpler than previously thought. Could 3D printing technology bridge science fiction and reality? The European Space Agency certainly thinks so.
Thursday the ESA announced, along with industrial partners like the renowned architects Foster + Partners, it would begin to test the feasibility of 3D printing using lunar soil as construction material, Phys.org reported.
"Terrestrial 3D printing technology has produced entire structures," said Laurent Pambaguian, heading the project for ESA.
"Our industrial team investigated if it could similarly be employed to build a lunar habitat."
Foster + Partners conceived a weight-bearing "catenary" dome design with a cellular structured wall built to shield against micrometeoroids and space radiation, which incorporates a pressurized inflatable to shelter astronauts. A hollow, closed-cell structure - think bird bones - provides a healthy combination of strength and weight.
"3D printing offers a potential means of facilitating lunar settlement with reduced logistics from Earth," added Scott Hovland of ESA's human spaceflight team.
"The new possibilities this work opens up can then be considered by international space agencies as part of the current development of a common exploration strategy."
"As a practice, we are used to designing for extreme climates on Earth and exploiting the environmental benefits of using local, sustainable materials," remarked Xavier De Kestelier of Foster + Partners Specialist Modelling Group.
"Our lunar habitation follows a similar logic."
Britain-based Monolite built the D-Shape printer, which uses a mobile printing array of nozzles o a 6 meter frame to spray a binding solution onto a sand-like building material. The 3D "printouts" are then built up gradually, layer by layer.
"First, we needed to mix the simulated lunar material with magnesium oxide. This turns it into 'paper' we can print with," explained Monolite founder Enrico Dini.
"Then for our structural 'ink' we apply a binding salt which converts material to a stone-like solid."
"Our current printer builds at a rate of around 2 m per hour, while our next-generation design should attain 3.5 m per hour, completing an entire building in a week."
Alta SpA, an Italian space research firm, also worked with Pisa-based engineering university Scuola Superiore Sant'Anna on adapting 3D printing techniques to a Moon mission and ensuring process quality control. The two also assessed the effect working in a vacuum would have on the 3D printing technology.
"The process is based on applying liquids but, of course, unprotected liquids boil away in vacuum," said Giovanni Cesaretti of Alta.
"So we inserted the 3D printer nozzle beneath the regolith layer. We found small 2 mm-scale droplets stay trapped by capillary forces in the soil, meaning the printing process can indeed work in vacuum."
"We have confirmed the basic concept, and assembled a capable team for follow-on work," said Laurent.
Researchers say other factors, such as controlling lunar dust - which is hazardous to breathe in - still require further study.