宇宙科学談話会
ISAS Space Science Colloquium & Space Science Seminar
FY2020
Atmospheric modeling of Earth-like planets around low-mass stars and the observational prospects
FUJII,Yuka（藤井 友香）
NAOJ
Characterization of temperate terrestrial planets around low-mass stars is a milestone in exoplanet observations. While having the size and incident flux similar to Earth's, they are likely to produce distinctive observable features due to the probable synchronous rotation and the different irradiation spectra. I will discuss the modeling efforts for their atmospheres and the observational prospects with upcoming missions.
Via Zoom / zoom 開催
OSIRIS-REx Particle Events and Juno Extended
TAKAHASHI,Yu（高橋 雄宇）
NASA Jet Propulsion Laboratory
This talk is going to be a two-part talk. The first part of the talk will be on the particles events we observed at Bennu. OSIRIS-REx arrived at asteroid Bennu in December 2018. During the first orbit campaign (Orbit-A), we observed many small ejecta launching off of the surface of Bennu. The characteristic of the particles' orbits could potentially jeopardize the spacecraft safety and it quickly became important to re-evaluate the mission architecture. One of the most important aspects of these particle events is that they proved very fortuitous for the radio science team in charge of gravity estimation. Their closer range to the surface proved very effective in estimating higher degree and order spherical harmonics coefficients that otherwise wouldn't have been possible from the spacecraft-only measurements. The second part of the talk will be on Juno extended mission. Juno arrived at Jupiter in July 2016 and has completed 30 science orbits as of January 2021. We have recently been granted an extended mission that will involve flybys of the three Galilean moons: Ganymede, Europa, and Io. The Ganymede flyby will occur in June 2021, Europa flyby in September 2022, and two back-to-back Io flybys in late 2023 and early 2024. Each flyby reduces the orbital period, eventually shrinking it from current 53 days to 33 days. We will discuss the challenges of the flybys we faced in the planning phase.
Via Zoom / zoom 開催
Challenges in Guidance, Navigation, and Control of Interplanetary CubeSats
Francesco Topputo（フランチェスコ トップート）
Politecnico di Milano
Deep-space CubeSats offer the possibility of augmenting and diversifying the Solar System exploration at a lower cost compared to traditional missions, thus providing high science-to-investment ratios. However, these systems having skeletal budgets and less control authority than classic, monolithic spacecraft, new challenges arise in governing their flight. Moreover, in order to scale down the operation costs, interplanetary CubeSats require augmented autonomy, so resulting in high-risk/high-gain space assets.
Via Zoom / zoom 開催
Perseverance and Beyond: Future Expectations of Planetary Surface and Subsurface Exploration with Highly Autonomous Robots
ONO Masahiro（小野 雅裕）
NASA Jet Propulsion Laboratory
The first half of this talk will be about NASA's Mars 2020 Mission (Perseverance), which the speaker has been involved from Phase A through Phase E, with emphases on autonomous driving, landing site selection, and robot operation. The second half of the talk will cover latest research activities on autonomy for future planetary mission concepts, including a highly autonomous Lunar/Mars rovers, Europa Lander, and Enceladus Vent Explorer.
Via Zoom / zoom 開催
Recent progress in the application of nucleosynthetic isotope anomalies in meteorites
YOKOYAMA Tetsuya（横山 哲也）
Tokyo Institute of Technology
Recent high precision isotope analyses of meteorites have revealed the presence of planetary-scale variabilities in isotopic compositions for a variety of elements. Some of these variations are nucleosynthetic in origin, suggesting the heterogeneous distribution of isotopically anomalous presolar components in the early Solar System. More importantly, carbonaceous chondrites (CCs) and other meteorites (noncarbonaceous meteorites; NCs) are found to form distinct clusters in the isotope spaces including ε50Ti-ε54Cr, Δ17O-ε54Cr, and ε95Mo-ε94Mo, indicating that the source materials feeding the CC and NC parent bodies were widely separated in the early Solar System. Such isotopic characteristics recorded in meteorites would reflect not only the dynamic history of material transport and mixing in the early Solar System, but also the origin of elements that were synthesized in various stellar environments before the onset of the Solar System. In this colloquium, I will present the recent progress in the application of nucleosynthetic isotope anomalies in meteorites, specifically focusing on the anomalies of trans-iron elements that were produced by the stellar nucleosynthesis of the s-, r-, and p-processes.
Via Zoom / zoom 開催
New insights into the Earth-Moon system revealed by KAGUYA
TERADA Kentaro（寺田 健太郎）
OSAKA University
I will present our recent new findings regarding the Earth-Moon system, revealed by the lunar orbiter KAGUYA. The first is the observation of terrestrial O+ ions around the Moon. The second topic is an asteroid shower on the Earth-Moon system 800 million years ago.
Via Zoom / zoom 開催