Design and Implementation of a Cross-Platform and Multi-Scale Workflow for Volatile-Rich Extraterrestrial Sample Analysis: From Contamination Control to Coordinated Analysis

• Introduction

The JAXA Hayabusa2 mission represents a significant milestone in planetary science. In December 2020, the mission successfully returned samples from two distinct sites of the carbonaceous, C-type, asteroid Ryugu. These samples were expected to provide critical insights into the origin of volatiles including water and organics on Earth, the thermal and aqueous histories of primitive bodies, and the physicochemical processes that related to the earliest stage of our Solar System.

F Following the successful recovery of the re-entry capsule, initial curation activities, primarily consisting of non-destructive observations (such as optical microscopy, FT-IR, MicrOmega, and weight measurements), were conducted at JAXA’s Extraterrestrial Sample Curation Center. Subsequently, the expanded analytical phase was launched to facilitate advanced and multi-institutional investigations by six initial analysis teams and the two Phase2 Curation teams including the Phase2 Curation Kochi team (Ph2K) [1-10].

• Preserve Pristine Nature of Ryugu sample: Contamination Control from curation facility to the institutes

The Ryugu samples are invaluable to planetary science due to their minimal terrestrial contamination, preserving volatiles and complex microstructures of minerals and organics. They preserve volatiles and complex microstructures of minerals and organics, providing insights into the early evolution of the Solar System [3-10]. To minimize contamination during transport to institutes both nationwide and internationally, we developed the Facility-to-Facility Transfer Container (FFTC) and individual sample containers [11] (Fig. 1). These were designed for use within Ryugu-dedicated clean chambers at the JAXA and prioritized ease of cleaning, use of same materials with the clean chamber, operability with thick Viton-coated butyl gloves, and long-term sealing using pure nitrogen.

• A Cross-Platform Pipeline for Extraterrestrial Sample Analysis

The cross-platform analytical pipeline of the Ph2K is designed to establish comprehensive protocols for the analysis of small-volume, volatile-rich extraterrestrial materials from asteroid Ryugu. Its primary objective is to characterize the mineralogical, petrological, chemical, and isotopic properties of the Ryugu samples at mm- to micrometer scales. To maximize scientific gain from the limited sample mass, the protocol follows a “non-destructive-first” strategy, advancing sequentially through increasingly invasive and ultimately destructive analytical techniques (Figs. 2, 3) [11-13].

• Results in case of Ryugu sample analysis by Ph2K

Ph2K plays a vital role in understanding of primitive Solar System materials. Samples returned from asteroid Ryugu exhibit bulk chemical compositions and oxygen isotopic compositions closely matching those of CI chondrites which is similar chemical compositions of the Sun, suggesting that Ryugu represents one of the most chemically primitive materials in the Solar System [e.g., 3-6, 13]. Our analyses revealed abundant hydrated minerals, such as phyllosilicates (i.e., serpentine and saponite) and carbonates, as well as isotopically heavy hydrogen and nitrogen isotopic compositions, pointing to low-temperature alteration and a formation in the cold outer Solar System. Organic matter, rich in aliphatic hydrocarbons, was associated with coarse-grained phyllosilicates, implying that these minerals may have provided environments favorable for organics. These findings support a scenario in which Ryugu accreted from icy and organic-rich particles, migrated inward, and potentially contributed to the delivery of water and organics to early Earth. Further studies of samples from other planetary explorations meteorite, and interplanetary dust particles are essential to expand our understanding of volatile transport and preservation in the early Solar System.

Additional findings by Ph2K include the identification of Ryugu’s precursor body [14], early aqueous alteration within 1.8–5.0 Myr after CAI formation [15], and low ejecta yields from asteroid during impacts [16]. Primitive noble gases with high xenon concentrations [17] and amorphous phases containing phosphorus and ammonium ions were also discovered, suggesting relevance to prebiotic chemistry on a carbonaceous asteroid [18]. Atmospheric exposure experiments further revealed rapid terrestrial alteration for the importance of meteorites and future returned sample curation and storage processes [19].

• Conclusion and perspective

Results from Ph2K have revealed mineralogical inventories, fine-scale isotopic variations, and signatures of low-temperature aqueous alteration with the complex water-mineral-organics coevolution on a carbonaceous asteroid. These findings may support the hypothesis that Ryugu and similar bodies may have played a key role in the delivery of water and organics to the early Earth.

The cross-platform pipeline by Ph2K will serve as a benchmark not only for Ryugu studies but also for future sample return missions, including MMX (Martian Moons eXploration). The continued refinement of small-sample analytical techniques will contribute significantly to the planetary science and the development of next-generation curation protocols [20].

• References

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