The first recovery of asteroidal samples to the Earth and subsequent two Japanese Sample Return Missions: Hayabusa, Hayabusa2, and MMX missions
Tomoki Nakamura (Tohoku University)
Mardi 12/06/2018, 10h00-11h00
Bat 713, salle de séminaires Galilée , CEA Saclay, Orme des Merisiers

Hayabusa mission has achieved the first successful recovery of asteroid samples back to the Earth. Developed on heritage of Hayabusa, Hayabusa2 was launched in Nov 2014, carried our Earth swing by in Dec 2015, and will arrive at the asteroid Ryugu 3 years later. Ryugu is classified to C-type asteroids that are expected to contain hydrated minerals such as serpentine and organic material. Ground based observations of Ryugu suggested that the surface mineralogical distribution seems to be heterogeneous, but most regions show reflectance spectra similar to partially dehydrated carbonaceous chondrites, implying that Ryugu surface material experienced hydration and subsequent dehydration by heating (Vilas 2008; Sugita et al. 2013; Perna et al. 2017).

After arrival we will perform a global mapping of Ryugu surface by using a visible telescope camera, a multiband visible to near infrared spectrometer, a near-infrared spectrometer, and a thermal infrared camera. Based on the results of the mapping, we will select several candidates for landing and sampling. The returned samples must maximize science return. We will perform first and second touchdown before and after solar conjunction of 2018 winter, respectively. The collected samples will come back to the Earth 2020 winter. Six groups of different disciplines were selected and organized for initial analysis of the returned samples. The first results of Ryugu sample analysis will be shown in early 2021.

The third Japanese sample return mission aims to recover rock samples from one of Martian moons, Phobos, in order to clarify the origin and formation process of the Martian moons. The spacecraft will be launched in 2024, arrive at Phobos in 2025, and comeback to the Earth 2029. In the seminar, I will introduce these three sample return missions and some important scientific achievements done by Hayabusa mission.

Organization: P. Hennebelle




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