[P-PS09] 月の科学と探査

[PPS09-19] Lunar Seismology: From Apollo to FSS and beyond

★Invited Papers

*川村 太一¹、Philippe Longonne¹、Mark Panning²、Ceri Nunn²、Sharon Kedar²、Neil Bowles³、Simon Calcutt³、Melanie Drilleau⁴、Raphael Garcia⁴、Anna Horleston⁵、Edward Miler²、David Mimoun⁴、Tom Pike⁶、Sebastien de Raucourt¹、Renee Weber⁷、Arnaud Wilhelm⁴、田中 智⁸、辻 健⁹、新谷 昌人¹⁰、小野寺 圭祐^10,1 (1.パリシテ大学, パリ地球物理研究所, フランス国立科学研究センター、2.Jet Propulsion Laboratory, California Institute of Technology、3.University of Oxford、4.ISAE Supaero、5.University of Bristol、6.Imperial College, London、7.NASA Marshall Space Flight Center、8.JAXA 宇宙航空研究開発機構　宇宙科学研究所、9.東京大学、10.東京大学地震研究所)

キーワード：惑星科学、月、地震学

Recently, lunar exploration has once again become a global trend and various space agencies are now planning a landing and manned missions to the Moon. In this new era of lunar exploration, seismic observations and exploration of the internal structure of the Moon is now being discussed in the community. In this presentation, we will first review the result from Apollo and recent studies to discuss the remaining questions related to the internal structure of the Moon and lunar seismology. Then we will introduce the future mission that are planned or under investigation. The first will be the Farside Seismic Suite (FSS). FSS was selected to fly under the PRISM (Payloads and Research Investigations on the Surface of the Moon) program, which NASA introduced to provide scientific payloads for the Commercial Lunar Payload Services (CLPS) program. FSS takes advantage of a flight-proven seismometer from the NASA InSight Mission; the vertical Very BroadBand (VBB) seismometer (the most sensitive seismometer ever built), and the Short Period (SP) sensor, the most mature compact triaxial sensor available for space applications. The seismometer will be deployed at Schrödinger Basin on the Moon’s farside to perform the first seismic monitoring at the lunar farside. They are packaged together as a self-sufficient, lander-mounted payload that can survive independently, with power, communications and thermal control allowing continuous operation over multiple lunations. Thus, FSS will outlive the delivery lander, and provide a long-lived seismic experiment capable of: 1. Investigating deep lunar structure and the difference between near and farside seismic activity; 2. Understanding how the lunar crust is affected by the development of an impact melt basin; 3. Evaluating the current micrometeorite impact rate and local tectonic activity. The second will be the Japanese Lunar Seismic Network project. Japan Aerospace Exploration Agency (JAXA) has identified 3 major scientific goals to be addressed in their future lunar missions and seismic observation network was listed as one of them. To achieve this, Japan has carried out a feasibility study (FS) for a lunar seismic observation system using an unmanned lander, as a step towards establishing a future seismic observation network. Key questions that were addressed during the FS was the challenge for night survival and long term observation. Continuous and long term observations are essential for a success of the seismic observation and this is very well demonstrated by success of Apollo and InSight. On the other hand, future lunar missions are likely to be closer to the pole which might have limitations in the power supply. We discuss our challenge and primary outcomes from the FS to realize our observation. Finally, we will describe our aim and goal to be achieved with the Japanese project.