source : www.sciencedaily.com
Research by West Virginia University students and faculty on how 3D printing works in a weightless environment aims to support long-term exploration and habitation on spaceships, the moon or Mars.
Extended missions in space require the manufacture of critical materials and equipment on site, rather than transporting these items from Earth. Members of the Microgravity Research Team said they believe 3D printing is the way to make that possible.
The team’s recent experiments focused on how a weightless microgravity environment affects 3D printing using titanium oxide foam, a material with potential applications ranging from UV blocking to water purification. ACS applied materials and interfaces published their findings.
“A spacecraft can’t carry an infinite amount of resources, so you have to maintain and recycle what you have and 3D printing makes that possible,” said lead author Jacob Cordonier, a doctoral student in mechanical and aerospace engineering at WVU Benjamin M. Statler College of Engineering and mineral resources. “You can only print what you need, which creates less waste. Our study looked at whether a 3D-printed titanium dioxide foam could protect against ultraviolet radiation in space and purify water.
“The research also allows us to see the role of gravity in how the foam emerges from the 3D printer’s nozzle and spreads onto a substrate. We saw differences in the shape of the filament when printing in microgravity compared to Earth’s gravity. And by changing additional variables in the printing process, such as write speed and extrusion pressure, we can paint a clearer picture of how all these parameters interact to tune the shape of the filament.”
Cordonier’s co-authors include current and former students Kyleigh Anderson, Ronan Butts, Ross O’Hara, Renee Garneau, and Nathanael Wimer. John Kuhlman, professor emeritus, and Konstantinos Sierros, associate professor and associate professor for research in the Department of Mechanical and Aerospace Engineering, also contributed to the paper.
Sierros has been overseeing the Microgravity Research Team’s titanium oxide foam studies since 2016. The work now takes place in his WVU labs, but originally required a ride on a Boeing 727. There, students pressed foam lines onto glass slides during 20-second periods of weightlessness. the aircraft was at the top of its parabolic flight path.
“Transporting even a kilogram of material into space is expensive and storage is limited, so we are exploring what is called ‘in-situ resource use,'” Sierros said. “We know that the moon contains deposits of minerals that are very similar to the titanium dioxide used to make our foam, so the idea is that you don’t have to transport equipment from here to space because we can get those raw materials on the moon to be able to mine and print the equipment needed for a mission.”
Necessary equipment includes shields against ultraviolet light, which poses a threat to astronauts, electronics and other space assets.
“On Earth, our atmosphere blocks a significant amount of UV light, but not all, and that’s why we get sunburned,” Cordonier said. “In space or on the moon, there is nothing that can mitigate this except your spacesuit or whatever coating is on your spacecraft or habitat.”
To measure titanium oxide foam’s effectiveness in blocking UV waves, “we would shine light ranging from the ultraviolet wavelengths all the way up to the visible light spectrum,” he explained. “We measured how much light came through the titanium oxide foam film we printed, how much was reflected, and how much was absorbed by the sample. We showed that the film blocks virtually all of the UV light that hits the sample and that very little visible light enters. Even with a thickness of only 200 microns, our material is effective at blocking UV radiation.”
Cordonier said the foam also showed photocatalytic properties, meaning it can use light to promote chemical reactions that can do things like purify air or water.
Team member Butts, a Wheeling student, led experiments using contact angle tests to analyze how changes in temperature affected the surface energy of the foam. Butts called the study “a different kind of challenge that students don’t always experience,” and said he especially appreciated the engagement component.
“Our team can do a lot of outreach with young students like the Scouts through WVU’s Merit Badge University. We can show them what we’re doing here to say, ‘Hey, this is something you could do too.’ ‘, Butts said.
According to Sierros, “We try to integrate research into students’ careers early on. We have a student subgroup that is purely hardware and they make the 3D printers. We have students who lead the development of materials, automation and data analysis. The students who have done this work with the support of two highly competitive NASA grants and participate in the entire research process. They have published peer-reviewed scientific papers and presented at conferences.”
Garneau, a student researcher from Winchester, Virginia, said her dream is for their 3D printer — specifically designed to be compact and automated — to make a six-month journey to the International Space Station. That would allow more extensive monitoring of the printing process than was possible during the 20-second free fall.
“This was a great experience,” Garneau said. “It was the first time I participated in a research project that did not produce predetermined results, as I have experienced in research-based classes. It was really rewarding to analyze the data and come to conclusions that were not based on fixed expectations.
“Our approach can help expand space exploration, allowing astronauts to use the resources they already have at their disposal without the need for a resupply mission.”
source : www.sciencedaily.com