Optimizing Spacesuit Layups with Strain-Hardening Fluids for Maximum Resistance during Low-Earth Orbit Exploration

Astronauts performing extravehicular activity (EVA) in low-Earth orbit (LEO) are exposed to extreme levels of solar- and charged-particle radiation, atomic oxygen, hard vacuum, temperature extremes, and potential impacts from micrometeoroid and orbital debris (MMOD) traveling at nominal speeds of 10 km/s. Their only protection from this environment is their pressurized EVA spacesuit. Select layers of the layup comprising the soft portion of the garment were treated with a shear-thickening fluid capable of withstanding the high-vacuum requirement of space. Two layups, one with LEO-STF-treated layers and one without, were exposed to LEO as part of the Materials International Space Station Experiments, MISSE-9, conducted by Alpha Space Test and Research Alliance, LLC. The samples were flown for a total of 9,267 orbits in the ram-orbiting direction of the International Space Station (ISS) affixed to the exterior of the ISS. This plane is subject to the highest exposure to atomic oxygen and moderate solar exposure. A suite of tests on the returned samples will be used to evaluate the robustness of the STF formulation fabric interaction and compared against Earth control samples. These include through puncture, optical properties, and hypervelocity impact tests which simulate MMOD impacts. Electron microscopy analysis will also be used to observe changes to the STF fabric substrate relationship.