Setting up a lunar base could be made much simpler by using a 3D printer to build it from local materials. Industrial partners including renowned architects Foster + Partners have joined with ESA to test the feasibility of 3D printing using lunar soil.
This is a case where 3d printing would win out over regular manufacturing. Most of the material is lunar dirt but with added magnesium oxide and a binding ink. This greatly reduces the weight of the material to be brought to the moon. There has been previous work on using carbon nanotubes and epoxy to make lunar concrete.
Foster + Partners devised a weight-bearing ‘catenary’ dome design with a cellular structured wall to shield against micrometeoroids and space radiation, incorporating a pressurised inflatable to shelter astronauts.
A hollow closed-cell structure – reminiscent of bird bones – provides a good combination of strength and weight.
The base’s design was guided in turn by the properties of 3D-printed lunar soil, with a 1.5 tonne building block produced as a demonstration.
The UK’s Monolite supplied the D-Shape printer, with a mobile printing array of nozzles on a 6 meter frame to spray a binding solution onto a sand-like building material.
“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 meter per hour, while our next-generation design should attain 3.5 meter per hour, completing an entire building in a week.”
“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.”
“Basaltic rock from one volcano in central Italy turns out to bear a 99.8% resemblance to lunar soil.”
Contour Crafting in the US has also looked at printing structures on the moon
Basic infrastructure elements:
– Landing pad
– Blast protection wall
– Shade walls
• Sulfur concrete
• Molten regolith
• Tensile reinforcement
•Layered without formwork