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

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

*Hiroaki Shiraishi¹, Takefumi Mitani¹, Satoshi Tanaka¹, Taichi Kawamura³, Keisuke Onodera¹², Ryuhei Yamada⁴, Shunichi Kamata⁵, Jun Kimura⁶, Hiroyuki Kurokawa⁷, Kiwamu Nishida², Yasuhito Sekine⁸, Takeshi Tsuji¹⁰, Hideki Murakami⁹, Ralph Lorenz¹¹ (1.Japan Aerospace Exploration Agency, Institute of Space and Astronautical Science, 2.Earthquake Research Institute / The University of Tokyo, 3.Universite Paris Cite Institut de physique du globe de Paris CNRS, 4.The University of Aizu, Revitalization and Creation Support Center, 5.Faculty of Science, Hokkaido University, 6.Osaka University, 7.The University of Tokyo, 8.Earth-Life Science Insitute, Tokyo Institute of Technology, 9.Kochi University, 10.Department of Systems Innovation, the University of Tokyo, 11.Johns Hopkins University Applied Physics Laboratory, 12.Institute for Planetary Materials, Okayama University)

Keywords:Dragonfly, Titan, Seismometer, Internal Structure

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.