Exploring Seismic Signal Detection and Source Identification of Atmospheric Entries: The Hayabusa2 Sample Return Capsule as a Benchmark

TL;DR

This study explores the potential of seismic signals to identify and analyze atmospheric entry events, using the Hayabusa2 sample return capsule as a benchmark, and compares seismic signatures across different re-entry types.

Contribution

It demonstrates that seismic data can distinguish ballistic re-entries from fragmented or airburst events, providing a new method for fireball source identification.

Findings

High correlation of seismic signals with ballistic trajectories

Lower correlation for fragmented or airburst events

Seismic data can help assess fragmentation during atmospheric entry

Abstract

This exploratory study investigates whether seismic signals can be used to infer fragmentation during a fireball event. Re-entry objects, particularly sample return capsules (SRCs) such as the one from the Hayabusa2 mission, behave similarly to slow meteors during atmospheric entry and provide valuable insights into natural fireball events. In this study, we initially analyse seismic signals from the Hayabusa2 SRC re-entry, which took place on December 5, 2020, over South Australia. The SRC's signature was captured by a dense network of seismic stations (Eakin, 2018; O'Donnell et al., 2020), offering a unique opportunity to investigate the signals' characteristics and verify their connection to the re-entry event. The ballistic trajectory was confirmed as the source shock mechanism for this event. We isolate this signal and use it as a reference for a ballistic shock signature and compare it to three other fireball case studies, including a suborbital re-entry and two natural meteoroids. Although factors such as local geology and atmospheric conditions were not considered in this preliminary study, our results show promise, with high correlations for events with purely ballistic trajectories and lower correlations for those involving fragmentation or airbursts. This implies that seismic data may be able to disambiguate whether any particular fireball event underwent significant fragmentation or airburst, key phenomena for assessing body strengths.