Amino acids on witness coupons collected from the ISAS/JAXA curation facility for the assessment and quality control of the Hayabusa2 sampling procedure

Abstract

The Hayabusa2 mission aims to obtain pristine samples from a near-Earth carbonaceous-type (C-type) asteroid, 162173 Ryugu, and return them to Earth. One of the scientific goals of the mission is to understand the origin and evolution of organic materials through the interactions between water and minerals in the early solar system. Thus, organic materials are the main focus of the analysis on the returned samples. The analysis of extraterrestrial organic materials, however, requires great care to avoid the introduction of terrestrial contaminants and artefacts to the samples. To investigate the potential for contamination, we performed an assessment through the amino acid analysis of witness coupons that were exposed in a clean chamber in an Institute of Space and Astronautical Science/Japan Aerospace Exploration Agency (ISAS/JAXA) curation room. In the study, the witness coupons were collected at different time periods, between 1 day and 1 month, to examine the accumulation rates of the contaminants. Seven common terrestrial amino acids (glycine, alanine, valine, leucine, isoleucine, proline, aspartic acid and glutamic acid) were detected on the witness coupons. Among them, glycine was found to be most abundant, with the highest concentration of 10 pmol/cm 2 detected on the day 7 witness coupon. Alanine was found in the next highest concentration, approximately one-third that of glycine. A time-dependent profile in terms of the increasing trend observed in the concentration from days 1 to 7 was found. The contaminants were considered to have multiple origins. Our results are similar to those reported by the National Aeronautics and Space Administration/Johnson Space Center (NASA/JSC) OSIRIS-REx team, which indicates that the quality control against terrestrial contaminants in our facility is at the same quantitative level as in their facility. The knowledge obtained on the contaminants in this study will provide important information for the curation procedure of the Hayabusa2-returned samples.

Concerns of Organic Contamination for Sample Return Space Missions

“…The total abundance of amino acids detected on the witness coupon that had been exposed to the clean chamber environment for 7 days was 0.3-1.2 ng/cm 2 . The most abundant terrestrial contaminant was glycine, which was accumulated at a calculated rate of 1.2 pmol (∼0.09 ng) /cm 2 /day (Sugahara et al 2018). This level of terrestrial deposition of glycine is low, compared to the amount of glycine detected in extra-terrestrial samples returned by space missions (e.g.…”

“…Witness coupons made from aluminium foil that were exposed in a clean chamber in the curation room at the ESCuC sample curation facility of JAXA were analysed in order to examine the type of contaminants and their accumulation rates (Sugahara et al 2018). Common terrestrial amino acids (glycine, alanine, valine, leucine, isoleucine, proline, aspartic acid and glutamic acid) were detected.…”

“…The examination of witness coupons which assessed the level of terrestrial organic contamination in the curation facilities of the Hayabusa2 and OSIRIS-REx missions have been reported recently (Dworkin et al 2017;Sugahara et al 2018) (Fig. 12).…”

Chemical assessment of the explosive chamber in the projector system of Hayabusa2 for asteroid sampling

“…Quality control for the sample process, including in ground-based procedures, is an important issue for sample return missions. The ESCuC (the Extraterrestrial Sample Curation Center) in the ISAS/JAXA facility (Yada et al, 2014;Uesugi et al, 2019) was assessed by an interlaboratory evaluation, and Sugahara et al (2018) reported an assessment of the clean room at ISAS/JAXA, which is intended to be used in the processing Hayabusa2 samples (cf. assessment on the OSIRIS-REx mission; Dworkin et al, 2017).…”

Connections Between Nuclear Physics and the Origin of Life - Examining the Origin of Biomolecular Chirality

“…From an observational perspective, a large segment of astrobiological exploration today is focused on locating and quantifying amino acids in stellar environments. This includes astronomical observations and theory [30,[39][40][41] as well as space missions to search for amino acids in comets and asteroids [42,43].…”