Re-entry prediction of objects with low-eccentricity orbits based on mean ballistic coefficients

Zhang Wei,Wang Xiuhong,Cui Wen,Wei Dong,Liu Xing

doi:10.1515/astro-2020-0006

Abstract

AbstractDuring re-entry objects with low-eccentricity orbits traverse a large portion of the dense atmospheric region almost every orbital revolution. Their perigee decays slowly, but the apogee decays rapidly. Because ballistic coefficients change with altitude, re-entry predictions of objects in low-eccentricity orbits are more difficult than objects in nearly circular orbits. Problems in orbit determination, such as large residuals and non-convergence, arise for this class of objects, especially in the case of sparse observations. In addition, it might be difficult to select suitable initial ballistic coefficient for re-entry prediction. We present a new re-entry prediction method based on mean ballistic coefficients for objects with low-eccentricity orbits. The mean ballistic coefficient reflects the average effect of atmospheric drag during one orbital revolution, and the coefficient is estimated using a semi-numerical method with a step size of one period. The method is tested using Iridium-52 which uses sparse observations as the data source, and ten other objects with low-eccentricity orbits which use TLEs as the data source. We also discuss the performance of the mean ballistic coefficient when used in the evolution of drag characteristics and orbit propagation. The results show that the mean ballistic coefficient is ideal for re-entry prediction and orbit propagation of objects with low-eccentricity orbits.

Highlights

Massive space objects cannot completely burn up during a re-entry; 10% to 40% of the mass may survive (Ailor et al 2005), and the surviving components may pose a threat to humans, buildings, and the environment (Choi et al 2017)
Re-entry predictions of Iridium-52 are carried out based on sparse observations with time intervals larger than ten hours; and re-entry predictions of other objects are carried out based on TLEs accessed from the space-track website
We propose a new method for reentry prediction based on the mean ballistic coefficient, which reflects the average effect of atmospheric drag during one revolution

Summary

Introduction

Massive space objects cannot completely burn up during a re-entry; 10% to 40% of the mass may survive (Ailor et al 2005), and the surviving components may pose a threat to humans, buildings, and the environment (Choi et al 2017). We call these objects risky re-entry objects. The drag coefficient depends on many parameters, such as the object’s shape, the surface material, and the composition and the temperature of the atmosphere.

Methods

Results

Conclusion