Evolutionary Debris Modeling of LEO and Cis-Lunar Space

Abstract

Space debris can be detrimental to missions in any orbital regime. With the advent of large satellite constellations in Low Earth Orbit (LEO) and planned return missions to the Moon, the risk created by fragmentation events in both LEO and cis-lunar space motivates an analysis of space debris evolution in these regions. Source-sink models allow for the study of debris evolution by considering various sources and sinks of debris, including atmospheric drag and fragmentation events. In this thesis, the evolution of the LEO environment is studied using a source-sink model with a variety of launch cases, including static and dynamic launch rates. A dynamical systems analysis is applied to the model to assess the stability of the LEO environment, finding stable equilibrium points for certain launch rates. Additionally, perturbations to the equilibrium state of the source-sink model are studied to determine the population of objects that trigger Kessler syndrome, and a new measure for orbital capacity is proposed. A calibrated explosion model is implemented in the source-sink model and an improved post-mission disposal model for satellites and rocket bodies is proposed. Possible improvements and current limitations of the source-sink model are explored, and the model’s predictions are validated against ESA’s DELTA model using 200 year-long simulations with a No-Further-Launch Case and an extrapolated launch case. The fragmentation analysis of orbiting objects that was conducted for the LEO environment is extended to a case study in cis-lunar space. The explosion model is implemented for a spacecraft in a Near-Rectilinear Halo Orbit around the Moon. The evolution of debris is studied in the Circular-Restricted Three-Body Problem, providing insight into the danger space debris poses to future missions.