Simplified structural fragmentation analysis of space debris subjected to destructive re-entry in the atmosphere

Thales Alenia Space in Italy (TASinI) in Turin had been developed a software for destructive reentry in the atmosphere named TADAP (Trajectory and Aerothermodynamic Debris Analysis Program) to the evaluation of the likelihood of a satellite's ground impact. A relevant development of this software would be inclusion of a structural model that require reliable results on the structural analysis of the satellite but with small calculation times. Therefore, the aim of this project was to find a possible simplification of the current FEM structural analysis, which requires high calculation times for the analysis of the entire satellite if it is performed at any moment of re-entry in the atmosphere. In order to have the stress values for comparison and to understand the structural behaviour of some components of the satellite, since there is no data concerning the loads or the stress on a satellite during re-entry, three components were analyzed: •??A ceramic bench, inside the satellite and difficult to thermally demise during re-entry also because made of ceramic material; •??A special washer made of a zinc-based alloy (EZACTM), part of the Demisable Joint (TASinI patent); •??The Demisable Joint, a solution to improve the demisability of the satellite, by facilitating the detachment of the external panels, improving the exposure of inner components to heat flux and thus increasing their demisability; From the results of FEM analysis on the study cases it’s clear that each component withstands at operative loads without breaking-up but they have a different behaviour at the atmospheric re-entry. The bench breaks between 80 and 90 km with peak of stress where there is the maximum temperature gradient and near the hole. The washer has peak of stress near the slot of the cleat and in the upper part in contact with the head of the screw, where is the preload, but it doesn’t entry in plastic field during his operative orbit lifetime at 100 km. The FEM analysis on the study cases show the structural behaviour of some components during atmospheric re-entry and give a reference to simplify the existing structural models.