Low Earth Orbit Drag Sail Degradation Due to Atomic Oxygen

As the orbital debris population continues to grow, so does the risk of collision to operational spacecraft. In response, the Federal Communications Commission updated its previous twenty-five year deorbit regulation to five years. Previously, many space objects could rely on natural atmospheric decay to deorbit within twenty-five years. However, this passive approach is not possible for many space objects with a smaller area to mass ratio under the new five-year regulation. While some propellant-carrying spacecraft can maneuver to a lower altitude, this is not possible for smaller, non-propulsive space objects such as rocket bodies and CubeSats. One proposed deorbit strategy involves deployment of a drag sail at end-of-life to increase atmospheric drag and therefore speed up orbital decay. However, exposure to atomic oxygen in the low Earth orbit environment degrades the thin membrane of the sail, compromising its functionality. To assess the feasibility of using drag sails for deorbit in low Earth orbit, it is necessary to determine the amount of atomic oxygen exposure the material can endure before a loss in structural integrity occurs. This study examines the survivability of single-sided aluminized Mylar when exposed to atomic oxygen generated by a capacitively coupled plasma system. Using binary logistic regression, the results indicate that, with 95% confidence, the aluminized side of Mylar has a 50% probability of survival after 3.6 months at International Space Station orbit, and the uncoated side has a 50% probability of survival after only 18 days.