Okazaki, R.; Miura, Y.N.; Takano, Y.; Sawada, H.; Sakamoto, K.; Yada, T.; Yamada, K.; Kawagucci, S.; Matsui, Y.; Hashizume, K.; Ishida, A.; Broadley, M.W.; Marty, B.; Byrne, D.; Füri, E.; et al .
Science Advances, 2022, 8, eabo7239
Abstract :
The Hayabusa2 spacecraft returned to Earth from the asteroid 162173 Ryugu on December 6, 2020. One day after the recovery, the gas species retained in the sample container were extracted and measured on-site, and stored in gas collection bottles. The container gas consists of helium and neon with an extraterrestrial 3He/4He and 20Ne/22Ne ratios, along with some contaminant terrestrial atmospheric gases. A mixture of solar and Earth’s atmospheric gas is the best explanation of the container gas composition. Fragmentation of Ryugu grains within the sample container is discussed based on the estimated amount of indigenous He and the size distribution of the recovered Ryugu grains. This is the first successful return of gas species from a near-Earth asteroid.