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

The increasing frequency of orbital launches and the associated proliferation of space debris have raised significant 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 deployment of the Yunhai-3 satellite. This incident, which generated a large population of new debris objects in low Earth orbit, underscores the need for further investigation into the physical mechanisms and dynamical characteristics of in-orbit fragmentation events. The main objective of this work is to estimate the pre-breakup orientation (attitude) of the CZ-6A second stage by analysing post-event data of the resulting debris cloud. The analysis entails acquiring and filtering Two-Line Element (TLEs) sets of the fragments followed by an inverse kinematic reconstruction to estimate the fragments’ ΔV components in the radial, tangential and normal directions. By combining the reconstructed ΔV distribution with the known geometry of the stage and the location of its propellant tanks, a likely explosion direction was hypothesized enabling the inference of a plausible pre-breakup attitude. Additional outcomes of the analysis include the determination of the fragmentation epoch and the reconstruction of the parent body’s orbital parameters.