AMINO ACID ANALYSIS OF WITNESS COUPONS COLLECTED FROM ISAS CURATION ROOMFOR THE QUALITY CONTROL OF HAYABUSA2 RETURN SAMPLE PROCEDURE
1

H. Sugahara1*, Y. Takano1,2, Y. Karouji3, M. Abe2 and Hayabusa2 project teamJapan Agency for Marine-Earth Science and Technology (JAMSTEC), Natsushima, Yokosuka 237-0061, Japan,
2
Japan Aerospace Exploration Agency (JAXA), Yoshinodai, Sagamihara 252-5210, Japan
3
Tokyo Metropolitan University (TMU), Hachioji, Tokyo 192-0397, Japan(*E-mail: h.sugahara@jamstec.go.jp)

One of the scientific goals of Hayabusa2 mission is to understand the origin and evolution of organic materials through interactions with water and minerals in the early solar system [1]. The characterization of organicmaterials (i.e. chemical composition, isotopic signature, abundance, morphology of complex organic molecules,etc.) in the returned sample has great importance for this purpose. The small-scale analysis of organic materials
in extraterrestrial samples needs great care with regards to terrestrial contamination including any artifact materials. Therefore, comprehensive and specific managements to minimize the terrestrial contamination throughoutthe mission are required. The assessment of the terrestrial contamination in the extraterrestrial samples has been
performed in the past sample return missions. The Stardust mission is the first sample return mission lead by
NASA, in which cometary grains were captured using aerogel from comet 81P/Wild 2 and successfully returnedto the Earth. For the assessment of the organic contamination throughout the mission, “witness coupons”, which
consist of aluminum or sapphire plates and aerogel tile, were used to track the origin and the incorporating routsof the contaminants in each process (e.g., construction of spacecraft, flight, recovery of the sample, etc.) [2]. The
analysis of the witness coupons showed that the contaminations during those processes were not significant, but
the aerogel used to capture the cometary grains contains carbon in a few simple forms (mostly as -CH3 groups),and Nylon-6 from a shipping bag could be a source of ε-amino-n-caproic acid (EACA, NH2(CH2)5COOH, thehydrolysis product of Nylon-6) [2, 3]. In the first Hayabusa mission, the spacecraft successfully landed on theasteroid Itokawa and directly sampled the surface particles using the sample catcher [4]. More than 450 particles(in ~µm scale) of the returned samples were classified into four categories based on their chemical composition.
The category 1 and 2 particles are indigenous to the asteroid, but the category 3 particles comprising carbonaceous materials are suggested to be terrestrial or artifact materials of multiple origins [5,6].
The purpose of the study is to assess the possible terrestrial organic contamination in the curation room for
the Hayabusa2 mission (cf. Design for Hayabusa2 sample container [7]). There are several working flow processes by the way of curation facility. We examined witness coupons, which are 4 cm2 (2 cm × 2 cm) aluminumfoils. They were placed in the curation room in ISAS /JAXA for 1 day, 2 day, 1 week, and 1 month. We performed amino acid analysis of the witness coupons because amino acid is one of the target molecules in theHayabusa2 mission, but also concerned about the possible terrestrial contaminants. Briefly, amino acids wereextracted in hot water for 12 hours at 110°C, and then HCl hydrolyzed for 12 hour at 110°C. They were converted to N-pivaloyl isopropyl (Pv/iPr) ester derivatives for gas chromatographic (GC) analysis [8]. The entire procedure through the extraction, hydrolysis, and derivatization were conducted in sealed glass ampules to minimize
the analytical background. As a reference of the amino acid assessment above, we also evaluated the volatileorganics in the curation room (class 1000 chamber) by using a thermal desorption-gas chromatography/mass
spectrometry (TD-GC/MS) [9]. We focused on aliphatic, aromatic (also, their isomer ratios), heterocyclic, andsulfur compounds (e.g., alkyl chain and aromatics with -thiol, -sulfide, -thiophene groups and elemental sulfur).
The organic concentration was very small but the most abundant species were 1-Rings of benzene, toluene andphenol. Here we discuss the present results and the procedure blank of the analysis in comparison with similarreport by OSIRIS-REX team [10].
References: [1] Tachibana S. et al. (2014) Geochem. J., 48, 571-587. [2] Sandford S. A. et al. (2010) Meteorit. Planet. Sci., 45, 406-433. [3] Elsila J. E. et al. (2009) Meteorit. Planet. Sci., 44, 1323-1330. [4] Tsuchiyama
A. et al. (2011) Science, 333, 1125-1128.; Yada T. et al. (2014) Meteorit. Planet. Sci., 49, 135-153. [5] Uesugi
M. et al. (2014) Earth, Planets and Space, 66, 102. [6] Ito M. et al. (2014) Earth, Planets and Space, 66, 91. [7]Okazaki R. et al. (2016) Space Sci. Rev., in press. [8] Chikaraishi Y. et al. (2010) in Earth, Life, Isotopes, Kyoto
Univ. Press, pp.367-386. [9] Takano Y. et al. (2015) Abstract for Hayabusa 2015: 3rd Symposium of Solar System Materials, P07 [10] McLain H. et al. (2015) Contamination Knowledge Report JSC Curation Cabinets, personal communication.