Shear Thickening Fluid Treated Space Suit Layups: MISSE-13 Low-Earth Orbit Studies

With upcoming lunar and Mars surface exploration a stronger, more resilient space suit is required to mitigate threats posed to astronauts. Vectran fabrics are of interest for this task due to the high strength of the fiber and its thermal stability. New fabric systems were developed using Vectran fabrics treated with shear thickening fluids (STF) known as STF-Armor�. STF incorporation has shown to provide enhancements of critical protection properties in conventional spacesuit materials. Here, results are presented from ISS experiments (MISSE-13) exploring the effects of low-earth orbit (LEO) on two Vectran based extra-vehicular activity (EVA) space suit layups that have been treated with a specially formulated, low-volatility, STF. One layup has an outer layer which is a modified version of the existing Orthofabric material which replaces the Nomex fibers with Vectran. Initial results showed this replacement led to a 50% increase in puncture while having a comparable aerial density. This fabric was also coated with a hydrophobic �lotus leaf� material that has shown dust mitigation benefits. The other layup outer layer consists of a silicone coated Vectran fabric. A control layup and a shear thickening fluid treated layup for each were exposed to LEO for approximately one year in the RAM orbiting direction of the ISS. While in LEO the samples were exposed to atomic oxygen (AO), space radiation and large temperature variations. Post flight analysis after MISSE 13 includes puncture resistance, optical properties, dust mitigation and scanning electron microscope (SEM) images. Comparisons are made to related materials flown in MISSE 9 & 10.