¹Tetsuya Yokoyama et al. (>10)
Meteoritics & Planetary Science (in Press) Open Access Link to Article [doi: 10.1111/maps.701411]
¹Department of Earth & Planetary Sciences, Institute of Science Tokyo, Meguro, Japan
Published by arrangement with John Wiley & Sons

Sample return missions play a significant role in planetary science by providing
pristine extraterrestrial materials. JAXA’s Hayabusa2 and NASA’s OSIRIS-REx missions
have returned samples from the C-type asteroids Ryugu and Bennu, respectively. The
chemical and mineralogical compositions of these samples closely resemble those of CI
chondrites, the traditional reference material for solar system abundances. Based on the
findings of the Hayabusa2 mission, JAXA launched the Ryugu Reference Project (RRP) to
maximize the scientific value of the returned samples and formed the RRP Measurement
Definition Team (RRP-MDT) to elucidate the RRP’s scientific goal and objectives. The
RRP-MDT defined the goal of RRP to reassess the elemental abundances and isotopic
compositions of the solar system through comprehensive analyses of the returned asteroid
samples and CI chondrites. To this end, the team recommended preparing homogeneously
powdered Ryugu reference materials (RRM) using approximately 750 and 400mg of
samples from Chambers A and C, respectively, to address observed compositional
heterogeneities. The team proposed to measure the elemental abundances and isotopic
compositions of the RRM by analytical techniques involving seven specific measurement
groups. Through comprehensive analytical methodologies, interlaboratory calibration, and
statistical evaluation, the RRP aims to refine our understanding of solar system formation
and evolution