When multiple talented engineers go into the same room (or Zoom call), awesome things can happen, especially when experts in other disciplines also pitch in. Case in point: engineers and designers recently collaborated on how to protect spacesuits from lunar dust.
Moondust is unlike the light powdery stuff we’re used to seeing on Earth. Earthly dust is more “well-behaved” — on your average windowsill, it obeys eviction under a soft cloth. But lunar soil is abrasive and fine-grained, and those tiny grains make it much more problematic. It sticks to everything. It can clog machinery, scratch lenses, ruin an entire mission. The long-term effects of moondust exposure are even more dangerous.
Astronauts have been aware of the dangers posed by moondust for some time. In a post-flight debriefing, Apollo 17 astronaut Eugene Cernan commented that “dust is probably one of the greatest inhibitors to a nominal operation on the Moon.” Discover magazine really laid into the problem in a 2019 wrap-up.
“Lunar dust, the Apollo astronauts learned, gets everywhere. Its jagged shape can scratch delicate spacesuit surfaces, while its dark color absorbs sunlight, overheating vital electronics. Breathing it in can even incite hay fever-like symptoms when astronauts return from moonwalks and shed their dust-covered spacesuits,” journalist Alison Klesman wrote.
A team at Stony Brook University recently examined what compounds in the lunar soil can do a lot of damage. According to a 2018 report from the university, lunar soil was toxic to human lung and mouse brain cells. Up to 90% of human lung cells and mouse neurons died when exposed to dust particles that mimic soils found on the Moon’s surface.
“We found that exposure of neuronal and lung epithelial cells in culture to several types of lunar soil simulants caused cell death and DNA damage,” said the authors of the paper, which appeared in GeoHealth.
NASA, at work on the dust problem, has been very interested in what university students might offer for dust-busting solutions. NASA asked university students around the country to help address lunar dust and through its 2021 competitive Breakthrough, Innovative, and Game-changing (BIG) Idea Challenge and the Space Grant project, NASA awarded seven university teams to develop their innovative lunar dust mitigation solutions.
One such response came from Brown University and Rhode Island School of Design, titled “Tufted Electrostatic Solution to Regolith Adhesion Dilemma.” So, what’s their big idea? Protective patches on spacesuits.
Patching things up
These special patches are made of electrostatic fibers that repel dust, offering layers of protection at the suit’s vulnerable points. The solution is dubbed TEST-RAD.
NASA seemed to like the idea, noting that it involves “systematic layers of protection at a spacesuit’s most vulnerable points through implementing tufted electrostatically charged repulsion fibers and regolith catching fibers where abrasion is most likely to occur.”
Brown Space Engineering also discussed how the patch works, implementing electrostatically charged repulsion fibers and regolith-catching fibers where abrasion is most likely to occur — regolith referring to loose rock and dust that blankets a layer of solid rock. Regolith is found on earth as well as on the moon.
Essentially, a layer of stainless steel mesh generates an electric field, which propagates up through the outer layer of tufted fibers.
“The electric field repels the lunar dust particles, which themselves carry a tiny electric charge. Particles that get through the electric field are likely to be trapped dense fiber tufts. Anything that gets through the tufts will be blocked by steel mesh,” said the Brown report. The tufted fibers are made of PEDOT, a conductive polymer material.
As Brian Clegg notes for Chemistry World, PEDOT is excellent because it also fits with the rest of the technology inside space suits.
“What sets PEDOT apart from many other polymers… is that it is both a conductor and transparent. The free electrons that make, for instance, metals good conductors tend also to make for easy absorption of photons, so by far the majority of conductors are opaque. But PEDOT lets the light through, making it ideal for applications that bring light and electrical circuitry together,” Clegg explains.
So could this approach truly become a standard? NASA has included the protective patch solution as one of seven chosen for further development, and the team gets research funds to build and test a system prototype. With the grant in place, the team aims to build the prototype and test it with the help of simulated lunar soil. The teams will present the results of their research and development to a panel of NASA and industry experts.
