Orbit Accuracy Simulation Analysis of Asteroid (469219) Kamoòalewa by Optical Observation of Tianwen-2

Abstract

China’s asteroid exploration mission, Tianwen-2, is scheduled to launch in 2025. Its first target, asteroid (469219) Kamoòalewa (also known as 2016 HO3), is a near-Earth object in co-orbit with Earth, with significant research value in terms of its motion evolution. Currently, there are limited ground observation data available for asteroid (469219) Kamoòalewa, which restricts its orbit accuracy. Tianwen-2, equipped with an optical payload, is expected to acquire a large amount of onboard optical observation data during its approach to Kamoòalewa. This will greatly improve the study situation of asteroid (469219) Kamoòalewa, which currently has only ground-based optical observation data and lacks publicly available observation data after 2021. By simulating the optical observation data of Tianwen-2 with a spacecraft orbit error of 2 km, the pre-mission evaluation of the orbit prediction accuracy of asteroid (469219) Kamoòalewa has been completed. The precision evaluation was performed using covariance analysis and numerical comparison methods. Within the possible range of observation precision considered in this study, it is estimated that the optical observation data from Tianwen-2 can improve the overall orbit accuracy of asteroid (469219) Kamoòalewa to better than 15 km. Additionally, an analysis was conducted to examine the differences and characteristics of the results obtained from the two precision evaluation methods.