Abstract
Spent upper stages are bodies consisting of components likely to survive re-entry, for example propellant tanks. Therefore, the re-entry of upper stages might be associated with high on-ground casualty risk. This paper presents a tool for re-entry prediction of spent rocket bodies in GTO based exclusively on Two Line Element set (TLE) data. TLE analysis and filtering, spacecraft parameters estimation, and combined state and parameters estimation are the main building blocks of the tool. The performance of the tool is assessed by computing the accuracy of the re-entry prediction of 92 GTO objects, which re-entered in the past 50 years