[P-PS01] Outer Solar System Exploration Today, and Tomorrow

[PPS01-18] Development status of seismometer for geophysiocal and meteorological package onboard Dragonfly

*白石 浩章¹、三谷 烈史¹、田中 智¹、川村 太一³、小野寺 圭祐¹²、山田 竜平⁴、鎌田 俊一⁵、木村 淳⁶、黒川 宏之⁷、西田 究²、関根 康人⁸、辻 健¹⁰、村上 英記⁹、Lorenz Ralph¹¹ (1.宇宙航空研究開発機構宇宙科学研究所、2.東京大学地震研究所、3.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、4.会津大学　復興創生支援センター、5.北海道大学　理学研究院、6.大阪大学、7.東京大学、8.東京工業大学地球生命研究所、9.高知大学、10.東京大学大学院　工学研究科、11.Johns Hopkins University Applied Physics Laboratory、12.岡山大学惑星物質研究所)

キーワード：ドラゴンフライ、タイタン、地震計、内部構造

Dragonfly is a relocatable lander that would use dual-quad rotors to perform soft-landings at multiple sites on the Saturn’s largest moon, Titan. The spacecraft will be launched in 2028 using a Falcon Heavy rocket and explore Titan for ~3 years in the mid-2030s. The Geophysical and Meteorological package (“DraGMet”) onboard Dragonfly is a suite of sensors to monitor the Titan' atmosphere and surface/subsurface environment. It includes a single-axis (vertical) short-period seismometer, as well as two sets of small geophones, which are installed on the lander skids, together with temperature and pressure sensors, anemometer for wind speed/direction, and methane and hydrogen sensors. At each landing site, the seismometer will be lowered to sit on the Titan's ground by a winch and protected from the wind loads using a pseudo-streamlined shield. During the seismic observation, the above-mentioned some of meteorological sensors should be simultaneously operated. The engineering models (EM) of seismometer package have been fabricated and their environmental tests have been conducted in these years. The tolerance of Titan’s environment, where the surface would be extremely cold at 94 Kelvin, has been confirmed and several key parameters are clarified inside a pressurized cryogenic chamber. Continuously, the assembly for DraGMet EM sensor suite and data processing unit (DPU) have been completed and their mechanical/electrical tests are conducting for the final design. On January 2025, the DraGMet subsystem CDR (Critical Design Review) was held and successfully passed. Consequently, the flight model (FM) fabrication of seisemometer package will soon start. In this paper, the outline of seismic experiment on Titan and the results of DraGMet EM performance/environmental tests will be presented.