The growing number of human-created objects in Low Earth Orbit (LEO) is increasing the risk of on-orbit collisions, posing threats to both short-term spaceflight safety and the long-term sustainability of the space environment. ARCLab is working to develop technical definitions of orbital capacity, quantify the number of satellites and other objects that can be accommodated in LEO based on different definitions and assumptions, identify high-impact interventions to improve capacity, and estimate future trends for the LEO environment. A major thrust of research in ARCLab is the ongoing development of the MIT Orbital Capacity Assessment Tool (MOCAT). MOCAT is a family of primarily multi-shell multi-species source-sink models, where the time evolution of many kinds of objects is considered. These include satellites slotted into orbits for mutual compatibility, unslotted satellites, non-functional derelict satellites, as well as tracked and untracked debris. In source-sink models, objects are aggregated in populations within each shell rather than considered individually, enabling rapid estimation and optimization of trends in the future space environment across large numbers of optimization variables.
Image: Andrea D’Ambrosio / MIT