Attitude reconstruction of the second stage of the CZ-6A rocket based on fragmentation data

The increasing frequency of orbital launches and the associated proliferation of space debris have raised growing concerns within the aerospace community. Among the most notable recent events is the fragmentation of the second stage of the Chinese Long March 6A (CZ-6A) rocket, which occurred on August 6, 2024, after the release of the Yunhai-3 satellite. This incident, which added a significant number of new debris objects to near-Earth orbit, underscores the need for further investigation into the root causes and dynamics of such events. The main objective of this work is to estimate the pre-breakup orientation (attitude) of the CZ-6A second stage by analyzing post-event data related to the resulting debris cloud. The analysis involves the acquisition and filtering of Two-Line Element sets (TLEs) of the fragments, an inverse kinematic reconstruction to compute the fragments’ ΔV components in the radial, tangential and normal directions. Knowing the stage geometry and the location of its tanks, a likely explosion direction was hypothesized and so a plausible attitude of the stage. The results suggest that the stage is oriented along the radial direction and so toward the Earth. Additional outcomes of the analysis comprise the determination of the fragmentation epoch and location, the reconstruction of the parent body’s orbital parameters and the estimation of the fragments’ area-to-mass ratios.