日本地球惑星科学連合2018年大会

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セッション記号 P (宇宙惑星科学) » P-PS 惑星科学

[P-PS05] 月の科学と探査

2018年5月23日(水) 10:45 〜 12:15 A01 (東京ベイ幕張ホール)

コンビーナ:長岡 央(早稲田大学理工学術院総合研究所)、諸田 智克(名古屋大学大学院環境学研究科)、西野 真木(名古屋大学宇宙地球環境研究所、共同)、鹿山 雅裕(東北大学大学院理学研究科地学専攻)、座長:鹿山 雅裕(東北大学)、山田 竜平

11:30 〜 11:45

[PPS05-10] The Concept and Science objectives of Lunar Penetrator Mission APPROACH

*田中 智1後藤 健1白石 浩章1川村 太一2山田 竜平3村上 英記4石原 吉明1早川 雅彦1小野寺 圭祐5白井 慶1 (1.宇宙航空研究開発機構、2.国立天文台、3.会津大学、4.高知大学、5.総合研究大学院大学)

キーワード:内部構造、ペネトレータ、月の起源と進化

A hard-landing mission using a penetrator has a great advantage, being lightweight compared to a soft landing system. LUNAR-A was the first approved as a lunar penetrator mission, however, it was cancelled in 2007 due to the delay of the penetrator development. After that, the penetrator technology was refined on the level of ground experiments in 2011. We re-design the mission to optimize small class mission using Epsilon launch vehicle and submitted to the M-class mission of JAXA as APPROACH (Advanced Penetrator Probe Applied for a Challenge of Hard landing) in January 2018. This paper reports concept and science objectives of this mission.

Mission concept of APPROACH is basically a succession of LUNAR-A mission heritage, although the number of the penetrator is reduced to one. On the other hand, we newly proposed to deploy impact monitor camera to determine epicenter of the seismic source precisely with the aid of ground network observations. The science instruments onboard the penetrator are two seismometers and heat-flow measurement respectively to achieve the science objectives.

The science objectives we defined are derived from one of the fundamental questions of science; “how and why life exists on the Earth and whether life is universal in the universe” , which is a prioritized scientific theme defined in RFI issued by Japanese Society of Planetary Sciences.

Our mission goal of “planetary science” is to clarify origin and evolution of the Moon, which preserves evidence of its formation and early evolution of the Earth-Moon system, and enable us to study the universality of habitable solar-system environment. Another goal of “planetary exploration technology” is to develop a new landing technology on the Moon and planets for in-situ observations of the Moon and planets easily and economically.

Today’s remaining questions in lunar science are summarized by Lunar Exploration Roadmap (Exploring the Moon in the 21st century) which was compiled by the Lunar Exploration Analysis Group (LEAG: https://www.lpi.usra.edu/leag/). By referring to this, we define the following three objectives and investigations of this mission;

Objective 1. Understand the physical conditions of the lunar-forming giant impact
Objective 2. Understand thermal evolution of the Moon.
Objective 3. Understand impact phenomena on planetary bodies.

On the other hand, in order to approach the goal of the planetary technology, we define one objective as;
Objective 4. Development of a hard-landing system for the in-situ geophysical observations on the Moon.

In planetary science, our proposed concept aims to contribute to a new era which will give reliable quantitative data on internal structure. We also aim to supply precision seismic and heat flow data to revise existing data by state-of-the-art instruments after 50 years from Apollo. The qualified data will be valuable for constraining an entire field, ranging from lunar history to the origin and evolution of the Earth-Moon system.

In planetary exploration technology, the concept aims to realize an easy access to the planetary surface. The low mass of the system has a major advantage to enable deployment of multiple landers which will provide an opportunity to conduct network observations simultaneously. Having this infrastructure could enable international collaboration or cooperation as a candidate of payload for the future planetary missions.