Development of Hayabusa2 sampler: Current status
S. Tachibana1, H. Sawada2, R. Okazaki3, Y. Takano4, K. Sakamoto2, Y. Karouji2, T. Yada2, M. Abe2, C. Okamoto5, H. Yano2, andHayabura2 sampler team1
Hokkaido Univ., 2Japan Aerospace Exploration Agency(JAXA), 3Kyushu Univ. 4Japan Agency for Marine-Earth Science& Technology (JAMSTEC), 5Kobe Univ.
E-mail: tachi@ep.sci.hokudai.ac.jp.
Introduction: Hayabusa2 is an asteroid exploration mission
to return surface samples of a C-type near-Earth asteroid(162173) 1999 JU3. Hayabusa2 will launch off in 2014, arrive at
1999 JU3 in mid-2018, and fully investigate and sample the asteroid at three different locations during its 18-month stay. The
spacecraft will return to the Earth with samples in December
2020. Return samples will be investigated by state-of-the-art
analytical techniques in 2020 to understand the long history ofthe Solar System from the beginning to the present by combining
with remote-sensing data sets and comparing with meteorites,
interplanetary dust particles, and future return samples.
Haybusa2 Sampler: The concept and design of the Hayabusa2 sampler are the same as the original Hayabusa with somemodifications to satisfy the scientific requirement. In order tocollect sufficient amount of samples compliant with both monolithic bedrock and regolith targets, a 5-g Ta projectile will be shotat 300 m/s at the timing of touchdown, and the ejecta will be put
into a sample catcher through an extendable sampler horn and aconical horn under a microgravity condition. Three projectiles
are equipped for sampling at three surface locations.
The sample catcher of the Hayabusa2, located at the top-endof conical horn, has three chambers to store samples obtained atthree locations separately. The sample catcher has a design thatis much easier to be taken apart during curation at the groundthan that of the original Hayabusa. After three sampling operations, the sample catcher is transported into the sample container
inside the Earth re-entry capsule and sealed. The container sealing method is changed from double fluorocarbon O-rings to analuminum metal seal to avoid the terrestrial air contamination
after the Earth return that happened for the Hayabusa container.
The new aluminum metal seal is designed to allow only a leak of
1 Pa air for 100 hours at the atmospheric pressure. To avoid further potential contamination, volatile components will be extracted prior to the opening of the container. The container will be
attached to a vacuum line, and the bottom of the container will bepierced with a needle to extract volatiles.
A back-up sampling method is also prepared; The tip of thesampler horn is turned up like the teeth of a comb, and surface
pebbles will be lifted up by the tip of the horn during touch down.
The lifted pebbles will be put into the sample catcher by deceleration of the spacecraft.
We here make a final report on the development of Hayabusa2 sampler, and also discuss the contamination control andReferences: [1] Tachibana, S., Abe, M., Arakawa, M., Fujimoto,M., Iijima, Y., Ishiguro, M., Kitazato, K., Kobayashi, N., Namiki,N., Okada, T., Okazaki, R., Sawada, H., Sugita, S., Takano, Y.,Tanaka, S., Watanabe, S., Yoshikawa, M., Kuninaka, H. andHayabusa2 project team (2014) Hayabusa-2: Scientific importance of samples returned from near-Earth C-type asteroid
1999 JU3. Geochemical Journal, in revision.