Japan Aerospace Exploration Agency

Kyushu University

Ibaraki University

Tokyo Institute of Technology

Japan Agency for Marine-Earth Science and Technology

Hokkaido University

Tohoku University

Kyoto University

Hiroshima University

The University of Tokyo

Summary of Presentation

Mass spectrometry and gas sampling of gas components in the sample container brought back to Earth by the asteroid explorer "Hayabusa2" were conducted. Thirty hours after the capsule recovery, the gas components inside the container were extracted, sampled, and mass analyzed using a gas sampling and analysis equipment ( GAEA ) on site in Australia. The collected gas was then distributed to domestic and international research institutions for precise isotopic analysis of the gas components. As a result, the container gas was found to be a mixture of solar wind and Earth's atmosphere. Calculations based on the amount of helium in the container indicated that the container gas most likely contained solar wind liberated when the surface of the Ryuguu sample was detached. The Hayabusa2 mission is the first time in the world that gas components from a near-Earth orbiting asteroid have been brought back to Earth in gaseous form.

Figure: Mass analysis results of the container gas by GAEA's onboard mass spectrometer (solid blue line). The horizontal axis is the ratio of mass (m) to ion valence (z)( m/z), and the vertical axis is the electrical signal intensity (arbitrary scale) of the ion corresponding to m/z in the mass spectrometer. There is an excess of gas (helium) with m/z of 4 compared to the instrument-derived gas (gray dotted line) and the Earth's atmospheric standard gas (red circle).

The Graduate School of Science and Earthquake Research Institute from The University of Tokyo participated in this research result. The following members of the Science group are participating in this research.

Shogo Tachibana	Professor, Department of Earth and Planetary Science, UTokyo Organization for Planetary and Space Science
Akihiro Kano	Professor, Department of Earth and Planetary Science
Seiji Sugita	Professor, Department of Earth and Planetary Science
Tomokatsu Morota	Associate Professor, Department of Earth and Planetary Science
Shizumoe Furuya	Project Specialist, UTokyo Organization for Planetary and Space Science

For more information, please visit the website of the Japan Aerospace Exploration Agency.

Journals

Journal name	Science Advances
Title of paper	First asteroid gas sample delivered by the Hayabusa2 mission: A treasure box from Ryugu
DOI number	10.1126/sciadv.abo7239