Research on constellation safety has concentrated on the interaction between constellations and the external debris environment, rather than on the risk a constellation poses to itself. This thesis develops PRISM, a Plane-Resolved Integrated Stochastic Model of a constellation's endogenous collision risk over its full operational lifetime. The model propagates a constellation through failures, maneuvers, fragmentations and disposal over decades, and attributes the resulting risk back to specific planes and shells. PRISM efficiently identifies which plane pairs of a given geometry drive risk, tracks the time-evolving localization of a freshly generated fragment cloud around its parent plane, and quantifies how much each shell's population could grow before it stops clearing its own debris, allowing operators and regulators to run the systematic analyses across different constellation geometries and debris mitigation policies needed to design safer constellations. ... Read more