10:00 AM - 10:30 AM
[U03-03] The Hayabusa2 reentry capsule retrieval operation and sample analysis
★Invited Papers
Keywords:Hayabusa2, asteroid, sample return, Solar System
The JAXA’s Hayabusa2 spacecraft explored C-type near-Earth asteroid (162173) Ryugu and landed on Ryugu at two different surface locations for sample collection in 2019. The Hayabusa2 spacecraft delivered its reentry capsule on December 6, 2020 to Woomera, South Australia. The sample container inside the capsule was carefully taken out of the reentry capsule in Woomera, and the gas inside the container was stored into several bottles at room temperature and at liquid nitrogen temperature. The sample container was put into a nitrogen-purged anti-vibration transportation box and was securely transported to the ISAS curation facility on December 8, 2020 (~57 hours after the capsule landing).
The sample container was then installed into the container opening system, which was used to take apart the outer lid of the container with keeping the pressure load onto the inner lid constant. The container with the opening system was the attached to the clean chamber, designed to maintain the Ryugu samples in vacuum and in pure nitrogen gas, on December 11. The container was opened on December 14 after the chamber evacuation.
Particles were found in two separate chambers inside the sample container, which were used for two landing operations at Ryugu. This indicates that the samples at the different surface locations were obtained successfully. The particles are black in color, consistent with the color of Ryugu boulders. There are millimeter- to centimeter-sized pebbles. Centimeter-sized grains, close to the maximum obtainable size (Sawada et al., 2017, Space Sci. Rev.), are found in the sample obtained during the second landing operation nearby the artificial crater. The total weight of the sample exceeds 5 g, which is far more than the mission requirement (100 mg) for scientific analysis (Tachibana et al., 2014, Geochem. J.). All the sample characteristics suggest that the Hayabusa2 sampler system worked efficiently and effectively at the Ryugu surface.
Because C-type asteroids have been considered to be parent bodies of carbonaceous chondrites, which contain pristine materials formed in the early Solar System, the detailed sample analysis, led by the Hayabusa2 project team, will focus on understanding the origin and early evolution of the Solar System along with the sample characterization. Carbonaceous chondrites are known to contain hydrated minerals and organic matter that could be a source of volatiles in the rocky planets including the Earth, and the presence of hydrated silicates has been confirmed spectroscopically on Ryugu (Kitazato et al., 2019, Science; Kitazato et al., 2021, Nature Astronomy). Water-related materials and organics are also the important target for the sample analysis to explore the possibility of the delivery of water and organics to the proto Earth from C-type asteroids.
The sample container was then installed into the container opening system, which was used to take apart the outer lid of the container with keeping the pressure load onto the inner lid constant. The container with the opening system was the attached to the clean chamber, designed to maintain the Ryugu samples in vacuum and in pure nitrogen gas, on December 11. The container was opened on December 14 after the chamber evacuation.
Particles were found in two separate chambers inside the sample container, which were used for two landing operations at Ryugu. This indicates that the samples at the different surface locations were obtained successfully. The particles are black in color, consistent with the color of Ryugu boulders. There are millimeter- to centimeter-sized pebbles. Centimeter-sized grains, close to the maximum obtainable size (Sawada et al., 2017, Space Sci. Rev.), are found in the sample obtained during the second landing operation nearby the artificial crater. The total weight of the sample exceeds 5 g, which is far more than the mission requirement (100 mg) for scientific analysis (Tachibana et al., 2014, Geochem. J.). All the sample characteristics suggest that the Hayabusa2 sampler system worked efficiently and effectively at the Ryugu surface.
Because C-type asteroids have been considered to be parent bodies of carbonaceous chondrites, which contain pristine materials formed in the early Solar System, the detailed sample analysis, led by the Hayabusa2 project team, will focus on understanding the origin and early evolution of the Solar System along with the sample characterization. Carbonaceous chondrites are known to contain hydrated minerals and organic matter that could be a source of volatiles in the rocky planets including the Earth, and the presence of hydrated silicates has been confirmed spectroscopically on Ryugu (Kitazato et al., 2019, Science; Kitazato et al., 2021, Nature Astronomy). Water-related materials and organics are also the important target for the sample analysis to explore the possibility of the delivery of water and organics to the proto Earth from C-type asteroids.