Visibility and observability of a Molniya breakup fragments across multiple orbits

The thesis explores the capabilities of space-based system for detection and monitoring of space debris. Traditionally, Space Situational Awareness (SSA) mainly relies on ground based architecture such as radar and optical systems but they are limited by atmospheric interference, geographical constraints and light conditions. Space-based observation o ers a better alternative, it provides continuous monitoring capabilities independent from terrestrial atmosphere or limitations. The simulation of the fragmentation of the FREGAT RB/CLUSTER 2 in a Molniya orbit, performed by the University of Padua by using the Collision Simulation Tool (CST), has been taken to generate the debris population. To analyze the cluster of fragments, a mathematical and geometrical model has been developed, it includes the reference frame transformation, the orbital dynamic of the fragments and the satellites’s orbits, in particular: Low Earth Orbit (LEO), speci cally Sun-Synchronous Orbits (SSO) at 550 km and 800 km; Medium Earth Orbit (MEO) and Geostationary Earth Orbit (GEO). The focus of this model is the de nition of the visibility and observability constraints that set the geometrical relationship between the Earth, the Sun, the debris and the observer that must be respected in order to make the fragments detectable . The same evaluation method is then applied to the four orbits with the nal goal of establish which one is the more e cient. Lastly, the impact of hardware speci cations, such as the reduction of the optics’ aperture diameter, on the overall monitoring performance is investigated. The results demonstrate that the e ciency of space-based detection is highly dependent to the observer’s orbital altitude and its relative position with the debris cloud.