Stable and Sustainable Orbital Capacity Solutions in Low Earth Orbit

Abstract The significant increase in the population of satellites in Low Earth Orbit raises concerns about the orbital carrying capacity, essentially the ability of the Low Earth Orbit environment to sustain a certain number of satellites without unsustainable levels of risk due to space debris or collisions. More in-orbit collisions can generate debris that further threatens operational satellites and human spaceflight missions. The open-source MIT Orbital Capacity Assessment Tool is adopted to optimize the number of satellites that fit in the Low Earth Orbit region under dynamical system equilibrium and sustainability constraints. The results show an opposite trend between active satellites and debris for a sustainable centuries-long space environment: the number of active satellites decreases with altitude, while the amount of debris increases. Higher altitudes exhibit a greater sensitivity to the number of satellites they can accommodate. Even a small number of satellites at high altitudes can significantly reduce the equilibrium orbital capacity of the space environment. Our results provide a stable upper boundary for the Low Earth Orbit carrying capacity, supported by a first- ever comparison and validation analysis between a source-sink model of the space environment population, incorporating a novel debris creation and spreading function, with Monte-Carlo methods.