A REPORT ON THE PREPARATION STATUS OF THE CURATION PROTOCOL FOR HAYABUSA2 SAMPLE
Y. Nakano1, T. Yada1, M. Abe1, T. Okada1 and S. Watanabe21
Japan Aerospace Exploration Agency (JAXA) and 2Nagoya University
We present an interim report on the returned sample curation protocol of Hayabusa2 project.
Hayabusa2 spacecraft was launched in 2014, and currently en route to a C type asteroid, called Ryugu, that is expected tobe rich in organic compounds and water-bearing minerals. Hayabusa2 is the second asteroid sampling project of JAXA and has
the following scientific and engineering objectives. The scientific objectives are to investigate chemical characteristics of the Ctype asteroid, especially the mineral – water – organic interactions by researching and analyzing its subsurface materials, andthereby to gain insight into its internal structure and reaccumulation process in its formation history. The engineering objectives
are to mature the technology, which had been developed for the past Hayabusa mission, by improving its robustness, reliability
and operability, and to execute the first impact experiment on the asteroid surface [1]. In 2018, Hayabusa2 will begin remotesensing observations over the surface of Ryugu, fire metal impactors to excavate its surface and perform touchdowns forcollecting its surface and/or subsurface materials. Hayabusa2 will leave Ryugu by 2019 and carry the sample, stored in vacuumtight containers, back to Earth in December 2020. Later, the containers will be transported to the Extraterrestrial Sample Curation
Center (ESCuC) in JAXA.
ESCuC is fully responsible for curating all the returned sample of Hayabusa2 and contribute to the Hayabusa2 projectthrough the curation work. We believe that the curation of extraterrestrial samples is a critical interface between sample return
missions and international science communities [2]. To accomplish our role, we have set following goals in our curation protocol:• Handling the returned sample without any contamination as possible;• Providing primary information about bulk returned sample and Ryugu grains obtained in the curation for theHayabusa2 project researchers and other scientists;• Creating the database of collected Ryugu grains.
The first goal is obvious, but is most important for ensuring a correctness and maximum output of scientific information
about the asteroid to be obtained from the returned sample. Especially so, since the source of the sample is identified
unambiguously unlike meteorites, which is an utmost advantage of the sample return mission. The goal depends seriously on
the curating work in ESCuC. Therefore, the curation protocol must reduce risk of terrestrial contamination as possible, as wellas prepare for every conceivable contingency.
Primary information about the returned sample, including the total weight and the size distribution of Ryugu grains andtheir physical and chemical states are very important for scientists to properly plan their researches and request suitable samples.
In case any contamination was detected in the returned sample, the level of contamination and when it happened is critical not
only to the scientists but also to the engineers who designed the spacecraft to improve the sampling system for future missions.
The chemical and physical properties of Ryugu sample are necessary information for us to optimize the allocation procedure of
the sample and would be interesting and informative to the scientists when they are designing research plans. We are planning
to use 5% of the returned sample for preliminary examination to obtain necessary data to characterize physical and chemical
properties of the returned sample. The sample allocation on request will also inform researchers of the size, weight and surface
state (e.g., IR spectra) of the requested samples. We have just started selecting analytical instruments and designing analyticalprocedures in our curation protocol. Part of the analysis should be consistent with the Goal-1 defined previously and/or ensure
no interruption in the allocation process.
As already noted, we are responsible for curating all the returned Ryugu sample. We are now developing a nomenclature
for pieces of the sample or grains that are collected from the container. We will create a database for the grains, including
necessary information such as their names, physical properties and histories of removing procedure that occurred during curation
and after allocation as well. Such database would facilitate management of the collected grains and allow scientists to access all
information they need.
We are still considering the best way to curate the returned sample of Hayabusa2 and recognize that there is room forfurther improvement in the current curation protocol.
References: [1] M. Yoshikawa, S. Watanabe and M. Abe (2012) Mission planning document of Hayabusa2, Section 2.3
the Mission Objectives. in Japanese; [2] C. Allen, J. Allton, G. Lofgren, K. Righter, R. Zeigler, and M. Zolensky (2013) Curating
NASA’s Extraterrestrial Samples. EOS Transactions American Geophysical Union., 94, 253-260.