Japan Geoscience Union Meeting 2023

Presentation information

[E] Online Poster

A (Atmospheric and Hydrospheric Sciences ) » A-OS Ocean Sciences & Ocean Environment

[A-OS14] Continental Oceanic Mutual Interaction - Planetary Scale Material Circulationn

Thu. May 25, 2023 10:45 AM - 12:15 PM Online Poster Zoom Room (4) (Online Poster)

convener:Yosuke Alexandre Yamashiki(Earth & Planetary Water Resources Assessment Laboratory Graduate School of Advanced Integrated Studies in Human Survivability Kyoto University), Swadhin Behera(Application Laboratory, JAMSTEC, 3173-25 Showa-machi, Yokohama 236-0001), Takanori Sasaki(Department of Astronomy, Kyoto University), Yukio Masumoto(Graduate School of Science, The University of Tokyo)

On-site poster schedule(2023/5/24 17:15-18:45)

10:45 AM - 12:15 PM

[AOS14-P03] Study on shielding of space radiation in lunar structures using watery material

*Emika Fujii1, Yosuke Alexandre Yamashiki1, Daikichi SEKI2, Tatsuhiko Sato3 (1.Graduate School of Advanced Integrated Studies in Human Survivability Kyoto University, 2.Faculty of Engineering, Urban and Environmental Engineering Kyushu University, 3.Japan Atomic Energy Agency)

Keywords:Radiation exposure, Lunar base

There are various barriers to the advancement of manned space missions, and cosmic radiation exposure is one of the most significant issues. In this study, for the objective of tackling the radiation issues for human space activity and in anticipation of the full-scale start and construction of the lunar base, we present the estimates of radiation exposure to the simple lunar base.
Firstly, we modeled the dome-shaped base whose radius was 20m on the moon surface and simulated the radiation dose inside the base when a solar particle event (SPE) with the scale equivalent to that occurred in September 1989. In our study, the PHITS code was employed in the cosmic radiation transport simulation. We estimated the thickness of the wall that would result in radiation dose inside the base being lower than 50mSv specified for occupational exposure. The wall materials are (1) water + polyethylene, (2) magnesium alloy, AZ91D and AZ31, (3) aluminum alloy, A7204, and (4) combinations of each alloy. The results showed that the thickness of the wall should be approximately 8 - 20 g/cm2, depending on the material.
We also calculated the cost of transportation from the information of more than 100 million yen/kg to transport from the earth’s ground to the moon’s surface. The transportation cost would be more than 45 trillion yen each if all the above wall materials were to be transported from the earth.
From this study, it can be concluded that it is unrealistic to construct a lunar base that can sufficiently shield the cosmic-radiation exposure due to SPE using the materials only transported from the earth. Thus, it is necessary to effectively utilize lunar surface resources in addition to transportation from the ground.