3D printing could turn lunar dust into essential supplies for astronauts such as shelters, household items and protective gear.
Extended missions in space require the on-site manufacture of crucial materials and equipment, rather than transporting those items from Earth.
Students at West Virginia University have been researching how 3D printing works in a weightless environment as a way to make that happen. They looked at how a microgravity environment affects 3D printing using titania foam, a material with potential applications ranging from ultraviolet (UV) light-blocking to water purification.
“Transporting even a kilogramme of material in space is expensive and storage is limited, so we’re looking into what is called ‘in situ resource utilisation’,” said associate professor Konstantinos Sierros.
The Moon contains deposits of minerals very similar to the titanium dioxide used in titania foam, which means the material could be mined there and then used to print the equipment necessary for a mission.
“A spacecraft can’t carry infinite resources, so you have to maintain and recycle what you have and 3D printing enables that,” said lead author Jacob Cordonier. “You can print only what you need, reducing waste. Our study looked at whether a 3D-printed titanium dioxide foam could protect against UV radiation in outer space and purify water.
“The research also allows us to see gravity’s role in how the foam comes out of the 3D printer nozzle and spreads onto a substrate. We’ve seen differences in the filament shape when printed in microgravity compared to Earth gravity. And by changing additional variables in the printing process, such as writing speed and extrusion pressure, we’re able to paint a clearer image of how all these parameters interact to tune the shape of the filament.”
The work initially required taking a ride on a Boeing 727. There, students printed lines of foam onto glass slides during 20-second periods of weightlessness when the jet was at the top of its parabolic flight path.
Necessary equipment includes shields against UV light, which poses a threat to astronauts, electronics and other space assets. On Earth, the atmosphere blocks a significant part of UV light, but in space or on the Moon, there’s nothing to mitigate it besides a spacesuit or the coating on a spacecraft.
The team has measured the titania foam’s effectiveness at blocking UV waves by shining light in various wavelengths onto it to see how much light was getting through, how much got reflected back and how much was absorbed by the sample.
They showed that the film blocks almost all the UV light hitting the sample and very little visible light gets through, even when only 200 microns thick.
The foam also demonstrated photocatalytic properties, meaning that it can use light to promote chemical reactions such as those that purify air or water.
The team hopes their 3D printer can eventually be flown up to the International Space Station so further tests can be carried out. This would enable more extensive monitoring of the printing process than was possible during the 20-second freefalls.
