Building a Lunar Base with 3D Printing

FYI,

"Building a Lunar Base with 3D Printing"
SpaceRef
http://www.spaceref.com/news/viewpr.rss.spacewire.html?pid=39966

: 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.
: "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 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. "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." The UK's Monolite supplied the D-Shape
: printer, with a mobile printing array of nozzles on a 6 m frame to
: spray a binding solution onto a sand-like building material.

: 3D 'printouts' are built up layer by layer - the company more
: typically uses its printer to create sculptures and is working on
: artificial coral reefs to help preserve beaches from energetic sea
: waves. "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."

: Italian space research firm Alta SpA 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 effect of working in a vacuum was also assessed.

: "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."

: Simulated lunar regolith is produced for scientific testing by
: specialist companies, typically sold by the kilogram. But the team
: required many tonnes for their work. "As another useful outcome, we
: discovered a European source of simulated lunar regolith," added
: Enrico. "Basaltic rock from one volcano in central Italy turns out
: to bear a 99.8% resemblance to lunar soil."

: "This project took place through ESA's General Studies Programme,
: used to look into new topics," Laurent commented. "We have
: confirmed the basic concept, and assembled a capable team for
: follow-on work."

: Factors such as controlling lunar dust - hazardous to breathe in
: - and thermal factors will require further study. 3D printing works
: best at room temperature but over much of the Moon temperatures vary enormously across days and nights lasting two weeks each. For
: potential settlement, the lunar poles offer the most moderate
: temperature range.

Mark Reiff