Ballistic Coefficient Estimation for Reentry Prediction of Rocket Bodies in Eccentric Orbits Based on TLE Data

David J Gondelach,Roberto Armellin,Aleksander A Lidtke

doi:10.1155/2017/7309637

Abstract

Spent rocket bodies in geostationary transfer orbit (GTO) pose impact risks to the Earth’s surface when they reenter the Earth’s atmosphere. To mitigate these risks, reentry prediction of GTO rocket bodies is required. In this paper, the reentry prediction of rocket bodies in eccentric orbits based on only Two-Line Element (TLE) data and using only ballistic coefficient (BC) estimation is assessed. The TLEs are preprocessed to filter out outliers and the BC is estimated using only semimajor axis data. The BC estimation and reentry prediction accuracy are analyzed by performing predictions for 101 rocket bodies initially in GTO and comparing with the actual reentry epoch at different times before reentry. Predictions using a single and multiple BC estimates and using state estimation by orbit determination are quantitatively compared with each other for the 101 upper stages.

Highlights

Rocket bodies in geostationary transfer orbits (GTOs) have their apogee near geosynchronous altitude and their perigee within the Earth’s atmosphere
For the left plots Two-Line Element (TLE) filtered on mean motion were used, whereas for the right plots the TLEs were filtered on mean motion and perigee radius
When using a median ballistic coefficient (BC) the individual TLE errors are averaged out and not compensated for, except for possible biases. These results suggest that estimation of the perigee altitude or eccentricity is required in order to improve the perigee data and the BC estimation and reentry prediction

Summary

Introduction

Rocket bodies in geostationary transfer orbits (GTOs) have their apogee near geosynchronous altitude and their perigee within the Earth’s atmosphere. The atmospheric drag reduces the orbital energy of the rocket bodies and lowers the orbit until reentry occurs. Lunisolar perturbations speed up or slow down this process by changing the eccentricity of the orbit and raising or lowering the perigee altitude, which in extreme cases results in direct reentry without draginduced decay. The reentry poses a risk to the Earth’s population because rocket bodies consist of components likely to survive the reentry and impact the Earth’s surface (such as propellant tanks) [1]. To be able to mitigate any risks due to deorbiting, the reentry of rocket bodies needs to be predicted

Objectives

Results

Conclusion