An Investigation of Material Resilience under Simulated Low Earth Orbit Environment

Abstract The study evaluates the atomic oxygen (AO) durability and surface stability of novel polymeric materials proposed for low Earth orbit (LEO) applications. The siloxane-, polyhedral oligomeric silsesquioxane (POSS)-, and polyimide (PI)-based films were exposed to ground-based AO conditions simulating up to six months of LEO-equivalent fluence. All three materials were systematically investigated through measurements of mass loss, surface roughness evolution, and defect formation to determine resistance to AO exposure. Results confirm the excellent capabilities of the PI-based film, a mature technology manufactured by DuPont, which exhibited the lowest mass loss at 0.35% and a minimal erosion rate of 0.07. Comparatively, still in early-stage research and development, siloxane- and POSS-based films demonstrated moderate erosion resistance at a 0.25 erosion rate and 1.21% mass loss for the former, and a 2.6 erosion rate with 15.75% mass loss for the latter. These results come with the caveat that siloxane- and POSS-based films were developed in smaller-scale government and academic laboratories and do not yet have a heritage of well-validated formulations to draw upon. All materials are proposed for inclusion in the upcoming six-month Materials International Space Station Experiment (MISSE) mission aboard the International Space Station (ISS) for further investigation and validation of AO-resistant properties, where they will be exposed to AO-rich conditions representative of real operational environments.