Modeling of 3D trajectory of Hayabusa2 re-entry based on acoustic observations

Yasuhiro Nishikawa , Masa-Yuki Yamamoto , Eleanor K. Sansom , Hadrien A. R. Devillepoix , Martin C. Towner , Yoshihiro Hiramatsu , Taichi Kawamura , Kazuhisa Fujita , Makoto Yoshikawa , Yoshiaki Ishihara , Islam Hamama , Norihisa Segawa , Yoshihiro Kakinami , Hiroshi Katao , Yuichiro Inoue , Philip A. Bland

On 2020 December 5 at 17:28 UTC, Japan Aerospace Exploration Agency's Hayabusa2 sample return capsule (SRC) re-entered Earth's atmosphere. The capsule passed through the atmosphere at supersonic speeds, emitting sound and light. The inaudible sound was recorded by infrasound sensors installed by Kochi University of Technology and Curtin University. Based on analysis of the recorded infrasound, the trajectory of the SRC in two cases, one with constant-velocity linear motion and the other with silent flight, could be estimated with an accuracy of ${0{_{.}^{\circ}}5}$ in elevation and 1° in direction. A comparison with optical observations suggests a state of flight in which no light is emitted but sound is emitted. In this paper, we describe the method and results of the trajectory estimation.

Keywords: atmospheric effects; instrumentation: miscellaneous; method: observational; shock waves; space vehicles: instruments

Domains: Sciences of the Universe [physics]

Yasuhiro Nishikawa, Masa-Yuki Yamamoto, Eleanor K. Sansom, Hadrien A. R. Devillepoix, Martin C. Towner, et al.. Modeling of 3D trajectory of Hayabusa2 re-entry based on acoustic observations. Publications of the Astronomical Society of Japan, 2022, pp.758-775. ⟨10.1093/pasj/psab126⟩. ⟨insu-03584322⟩