A Multi Model Electromagnetic Sounding Investigation of the Lunar Interior

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Neutron Measurements at the Lunar Surface (NMLS)

The Neutron Measurement System (NMS-Lunar) is an instrument payload manifested on Astrobotics Peregrine Mission One (M1). Astrobotic Mission One will land at Lacus Mortis (~44oN, 254oE). Astrobotic will fly up to fourteen NASA payloads to the lunar surface in addition to other payload customers on M1. NMS-Lunar is a re-design of the MSFC Fast Neutron Spectrometer (FNS) currently operating on the ISS. The design of NMS-Lunar enables operation on the lunar surface, integration onto the Peregrine lander, and measurement of thermal neutron count rates on the lunar surface. The primary science objectives for NMS-Lunar is to provide ground truth of mapped neutron data from the Lunar Reconnaissance Orbiter and Lunar Prospector missions. Neutrons are created when galactic cosmic rays interact with the lunar regolith, and can provide valuable elemental composition information

The Importance of Nightside Magnetometer Observations for Electromagnetic Sounding of the Moon

Understanding the structure and composition of the lunar interior is a fundamental goal in furthering our knowledge of the formation and subsequent evolution of the Earth-Moon system. Among various methods, electromagnetic sounding is a valuable approach to constraining lunar interior structure. Recent analyses of plasma and field observations provide a wealth of understanding about the dynamics of the lunar plasma environment. To perform Time Domain EM (TDEM) Sounding at the Moon, the first step is to characterize the dynamic plasma environment, and to be able to isolate geophysically induced currents from concurrently present plasma currents. The TDEM Sounding transfer function method focuses on analysis of the nightside observations when the Moon is immersed in the solar wind. This method requires two simultaneous observations: an upstream reference measuring the pristine solar wind, and one downstream at or near the lunar surface. This method was last performed during Apollo and assumed the induced fields on the nightside of the Moon expand as in an undisturbed vacuum within the wake cavity. Our results indicate that EM sounding of airless bodies in the solar wind must be interpreted via self-consistent plasma models in order to untangle plasma and induced field contributions, with implications not only at the Moon but at all airless bodies exposed to the solar wind. Nightside TDEM sounding has the capability to advance the state of knowledge of the field of lunar science. This requires magnetometer operations to withstand the harsh conditions of the lunar night

The importance of local long-duration STEM mentorship as a global mechanism for increasing diversity at all levels of education

We begin with a brief review of the progress being made by the professional space physics community to increase diversity and inclusion. These efforts have been primarily centered on overcoming barriers that have inhibited existing underrepresented minority space physics professionals from being successful at all levels of academic, mission, and administrative achievement. While we find these remediations to be essential, we must recognize that our ability to achieve a diverse professional workforce representative of the US population depends on achieving a diverse population of researchers entering the field. That means the greatest gains can only be achieved by actions that reach into the educational system. We identify and discuss possible issues within the traditional formal education and developmental environment of young inquiring minds, including gaps in resources, the pressure to bring in income during secondary school and graduate school matriculation, and the cultural biases against research careers. We highlight the importance of local mentorship and age-appropriate research-like activities within all levels of education, including Kindergarten through bachelor’s and advanced degree programs, as a means of overcoming barriers to becoming a respected contributing member of the space physics research community. We note these issues extend beyond space physics into all STEM fields. These activities can provide road maps into research careers, practice age-appropriate skills, and provide an avenue for current researchers to become mentors. Specifically, we advocate the development of a formal program of professional chapters for colleges and age-appropriate research-oriented programs for K-12 schools and encourage strong collaborative affiliations with other professional societies. At the core of this is the development and implementation of informed, persistent mentoring

The Impact of the 1994 Japanese Electoral Reform : A comparative perspective(<Featured Theme>Party Politics Beyond Electoral Reform)

1994年に選挙制度を軸とする政治改革が行われ小選挙区比例代表並立制が施工された.そこで,改革後は政策を軸とした政党中心のインセンティブが働き政権交代の起こる二大政党制の出現が期待された.しかし,現実には地方農村地区を支持基盤に持つ自民党が都市部を基盤にする公明党と連立政権を組んだり,民主党内に自民党と旧社会党の流れを汲む議員が存在したりと有権者にとっては分かり難い政治が続いている.また,民主党の台頭から二大政党制へ移行しているようにも思われるが,アメリカ合衆国のように一つの政党が政権をとり,後には野党が政権党に返り咲くというような二大政党制の特徴が現実化されていないことも事実である.本研究では,政治改革の遅れの一因は国と地方との選挙制度の不一致が原因であるという制度不均一仮説を国際比較データを用いて検証する.The Japanese Lower House adopted a mixed electoral rule in 1994, and this new rule seems to have brought about some important changes in Japanese party politics. However, many still claim that the new electoral system has been slow in pushing the original intent of the reforms -discouraging pork barrel politics, promoting cohesive party platforms, and creating an environment conducive to alternation of parties in power. The purpose of our panel is to show that the inconsistency of electoral rules between the national and local elections is the cause of this hindrance. My paper examines Japanese party politics from a comparative perspective and exhibits evidence that the barriers to reform also grew out of the local level

CHARACTERIZING ELYSIUM'S MAGMATIC EVOLUTION AND CHEMISTRY INITIAL STUDY

International audienceIntroduction: The Elysium volcanic province (EVP) is a location of great geologic interest on Mars. EVP is notable not only for the presence of three shield volcanoes, Elysium, Alber, and Hecates, but also for some of the most recent eruptions on the planet, with some interpretations suggesting activity even in the last few million years. Its predominantly Amazonian surface age and isolation in the northern hemisphere away from other volcano-tectonic regions make it an ideal locale to investigate igneous compositions during the most recent geologic period on Mars. Specifically, EVP experienced an extended period of volcanism; compared to large igneous provinces on Earth, the martian context has persisted orders of magnitude longer. Therefore, changes in mantle chemistry, pressure , and temperature are expected, as well as changes in fractional crystallization processes and crustal contamination. Due to the coarse length scale of the observation resolution and lack of resolved local features, these systems appear much simpler than their terrestrial counterpart. In addition, regional scale changes in eruptive processes of any given martian volcanic province over geologic time are still poorly understood. Related investigations are crucial for understanding how the martian crust and mantle have evolved in the absence of Earth-like plate-tectonics. Consequently, this project helps fill this knowledge gap by assessing the compositional evolution of Elysium as a major martian volcanic province, using remote sensing data sets (Mars Odyssey Gamma Ray and neutron Spectrometer suite (GRS), and gravity) and modeling (pet-rologic and thermoelastic). By analyzing data based on predictions from petro-logic modeling, we develop an expansive geologic history for the region that spans over 3 Ga. Our work shows a compositional transition in Elysium's volcan-ism coupled to differences in geologic age between NW and SE regions [1] (mapped Geology summarized in Fig. 1). The continuity of volcanic activity, and the notable spatiotemporal changes in the abundance of heat-producing radioactive elements (K and Th) along with others (Al, Ca, and Fe in particular) make this region an ideal case study for the evolution of volcan-ism on Mars [1,2]. Here we perform a detailed petro-logical and thermoelastic modeling to test the emerging hypothesis that compositional variability within EVP resulted from spatiotemporal changes in the depth of magma formation and present initial results

The Lunar Geophysical Network Landing Sites Science Rationale

International audienceThe Lunar Geophysical Network (LGN) mission is proposed to land on the Moon in 2030 and deploy packages at four locations to enable geophysical measurements for 6-10 yr. Returning to the lunar surface with a long-lived geophysical network is a key next step to advance lunar and planetary science. LGN will greatly expand our primarily Apollo-based knowledge of the deep lunar interior by identifying and characterizing mantle melt layers, as well as core size and state. To meet the mission objectives, the instrument suite provides complementary seismic, geodetic, heat flow, and electromagnetic observations. We discuss the network landing site requirements and provide example sites that meet these requirements. Landing site selection will continue to be optimized throughout the formulation of this mission. Possible sites include the P-5 region within the Procellarum KREEP Terrane (PKT; (lat: 15°; long: -35°), Schickard Basin (lat: -44.°3; long: -55.°1), Crisium Basin (lat: 18.°5; long: 61.°8), and the farside Korolev Basin (lat: -2.°4; long: -159.°3). Network optimization considers the best locations to observe seismic core phases, e.g., ScS and PKP. Ray path density and proximity to young fault scarps are also analyzed to provide increased opportunities for seismic observations. Geodetic constraints require the network to have at least three nearside stations at maximum limb distances. Heat flow and electromagnetic measurements should be obtained away from terrane boundaries and from magnetic anomalies at locations representative of global trends. An in-depth case study is provided for Crisium. In addition, we discuss the consequences for scientific return of less than optimal locations or number of stations

Crustal and time-varying magnetic fields at the InSight landing site on Mars

International audienceMagnetic fields provide a window into a planet’s interior structure and evolution, including its atmospheric and space environments. Satellites at Mars have measured crustal magnetic fields indicating an ancient dynamo. These crustal fields interact with the solar wind to generate transient fields and electric currents in Mars’s upper atmosphere. Surface magnetic field data play a key role in understanding these effects and the dynamo. Here we report measurements of magnetic field strength and direction at the InSight (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) landing site on Mars. We find that the field is ten times stronger than predicted by satellite-based models. We infer magnetized rocks beneath the surface, within ~150 km of the landing site, consistent with a past dynamo with Earth-like strength. Geological mapping and InSight seismic data suggest that much or all of the magnetization sources are carried in basement rocks, which are at least 3.9 billion years old and are overlain by between 200 m and ~10 km of lava flows and modified ancient terrain. Daily variations in the magnetic field indicate contributions from ionospheric currents at 120 km to 180 km altitude. Higher-frequency variations are also observed; their origin is unknown, but they probably propagate from even higher altitudes to the surface. We propose that the time-varying fields can be used to investigate the electrical conductivity structure of the martian interio