The project vision is to enable sensors and other components to be durable to the unique low Mars orbital environment so that science and pathfinder data can be reliably and accurately obtained to enable human exploration of Mars. Ground testing capability that can reproduce degradation of sensors observed in the low Mars orbital environment needs to be developed to enable designers to test sensor materials and components prior to flight. It is important to invest in this proposal because we are venturing farther into the solar system where spacecraft are too distant to be easily repaired if something goes wrong. We need to be able to simulate the low Mars orbital environment here so that we select sensor materials that we know will survive a Mars mission prior to launch. It is known that Mars upper atmosphere contains atomic oxygen, but the Mars upper atmosphere is much harsher than was originally thought. Langmuir probe sensor surfaces tested under Low Earth Orbit (LEO) atomic oxygen conditions for the MAVEN (Mars Atmosphere and Volatile EvolutioN) mission, which performed under LEO environment conditions, experienced unexpected loss in performance in low Mars orbit. The goal is to understand the cause of degradation of Langmuir probe and other sensor materials observed on the MAVEN spacecraft and develop a capability to simulate the degradation on the ground to enable development of Mars environment durable sensors.