[P-CG20] 宇宙・惑星探査の将来計画および関連する機器開発の展望

[PCG20-P06] Pre-flight calibration of the ion energy mass spectrum analyzer for the Martian Moons eXploration (MMX) mission

*横田 勝一郎¹、斎藤 義文²、浅村 和史²、笠原 慧³、北村 悠稀¹ (1.大阪大学大学院・理学研究科、2.宇宙航空研究開発機構・宇宙科学研究所、3.東京大学大学院・理学系研究科)

キーワード：宇宙プラズマ計測、質量分析、火星衛星探査計画

We have developed an ion energy mass spectrum analyzer for the Martian Moons eXploration (MMX) mission to measure the three-dimensional velocity distribution function and mass profile of low-energy ions around the Mars-Moon system. The ion analyzer employs nearly the same measurement techniques as that of Ion energy Mass Analyzer (IMA) for the Kaguya mission and mass spectrum analyzer (MSA) for BepiColombo/MIO. The hemispheric field of view (FOV) is acquired by a couple of angular scanning deflectors, and the energy/charge and mass/charge are determined for each ion by an electrostatic analyzer and a linear-electric-field (LEF) time-of-flight (TOF) analyzer, respectively, with an enhanced mass resolution of M/ΔM∼100.
The ion analyzer, together with magnetometers, constitutes the mass spectrum analyzer (MSA), one of the scientific instruments on board the MMX spacecraft. The performance tests and pre-flight calibration presented here were conducted from the end of 2022 to the beginning of 2024. The FM of MSA was handed over to the MMX spacecraft system. The FM of MSA was integrated into the spacecraft exploration module, and the preflight test of the spacecraft system has started. We will report on the instrumentation of the ion analyzer, and results of the performance tests of its flight model (FM) comparing with that estimated with a numerical model for its design.