• Title/Summary/Keyword: Lunar regolith

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Basic Lunar Topography and Geology for Space Scientists (우주과학자에게 필요한 달의 지형과 지질)

  • Kim, Yong Ha;Choi, Sung Hi;Yu, Yongjae;Kim, Kyeong Ja
    • Journal of Space Technology and Applications
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    • v.1 no.2
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    • pp.217-240
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    • 2021
  • Upon the human exploration era of the Moon, this paper introduces lunar topography and geologic fundamentals to space scientists. The origin of scientific terminology for the lunar topography was briefly summarized, and the extension of the current Korean terminology is suggested. Specifically, we suggest the most representative lunar topography that are useful to laymen as 1 ocean (Oceanus Procellarum), 10 maria (Mare Imbrium, Mare Serenitatis, Mare Tranuillitatis, Mare Nectaris, Mare Fecundatis, Mare Crisium, Mare Vaporium, Mare Cognitum, Mare Humorum, Mare Nubium), 6 great craters (Tyco, Copernicus, Kepler, Aristachus, Stebinus, Langrenus). We also suggest Korean terms for highland, maria, mountains, crater, rille, rima, graben, dome, lava tube, wrinkle ridge, trench, rupes, and regolith. In addition, we introduce the standard model for the lunar interior and typical rocks. According to the standard model on the basis of historical impact events, the lunar geological eras are classified as Pre-Nectarian, Nectarian, Imbrian, Erathostenesian, and Copernican in chronologic order. Finally, we summarize the latest discovery records on the water on the Moon, and introduce the concept of water extraction from the lunar soil, which is to be developed by the Korea Institute of Geoscience and Mineral Resources (KIGAM).

Maturity of the Crater Rim Walls as a function of the Crater Size

  • SIM, Chae Kyung;Kim, Sungsoo S.;Jeong, Minsup
    • The Bulletin of The Korean Astronomical Society
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    • v.40 no.2
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    • pp.45.3-46
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    • 2015
  • Space weathering agents such as micrometeoroids and solar wind particles continuously age the uppermost regolith of the lunar surface by comminuting as well as darkening and reddening. Among several maturity indices, we investigate median grain size () and optical maturity (OMAT) of the crater rim walls. Crater rim wall is the most immature place among the impact crater features because the vertical mixing process by mass-movement can enhance the gardening of regolith and the supply of immature materials in the deeper layer to the surface. More than 140 simple and complex craters were considered. Both and OMAT values of the inner rim wall initially increase as the crater size increases until ~10-20 km, then decrease. This transition crater size happens to correspond to the transition diameter from simple to complex craters. For larger craters, i.e., complex craters, it is clear that the inner rim wall of the craters formed in recent eras tend to remain fresh and become mature along with time. For the simple crater case, smaller craters are more mature, which is opposite to the case of complex craters. This is thought to be because smaller craters become flattened more quickly, thus have smaller vertical mixing in the regolith due to mass-movement. We will also discuss on the maturity indices of the crater rim walls at high latitudes as a function of the position angle to see the latitude dependence of the space weathering process.

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Heat Flux Analysis of Lunar Lander for Potential Landing Candidate Area (달 착륙선의 착륙 후보지별 열 유입량 분석)

  • Park, Tae-Yong;Chae, Bong-Geon;Lee, Jang-Joon;Kim, Jung-Hoon;Oh, Hyun-Ung
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.46 no.4
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    • pp.324-331
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    • 2018
  • The thermal environment on lunar surface is more severe than that of earth's surface or low earth orbit because of the long daytime and nighttime due to 28 days of rotation cycle of moon. Thus, analyzing heat flux on lunar lander at potential landing sites is important to determine the landing site in its initial design phase. In this study, thermal model of lunar regolith that can simulate lunar surface temperature was constructed for analyzing thermal characteristics according to the potential landing sites of lunar lander. The heat flux analyses were performed various latitudes of equator, mid-latitude, polar regions, lunar mare and highland. In addition, we also investigated the heat flux of lunar lander when it is landed on adjacent area to hill.

Development of a Coarse Lunar Soil Model Using Discrete Element Method (이산요소법을 이용한 성긴 달토양 수치해석모델 개발)

  • Jeong, Hyun-Jae;Lim, Jae Hyuk;Kim, Jin-Won
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.47 no.1
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    • pp.26-34
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    • 2019
  • In this paper, a coarse lunar soil model is developed using discrete element method and its computed physical properties are compared with those of the actual lunar soil for its validation. The surface of the actual moon consists of numerous craters and rocks of various sizes, and it is covered with fine dry soil which seriously affects the landing stability of the lunar lander. Therefore, in consideration of the environment of the lunar regolith, the lunar soil is realized using discrete element method. To validate the coarse model of lunar soil, the simulations of the indentation test and the direct shear test are performed to check the physical properties(indentation depth, cohesion stress, internal friction angle). To examine the performance of the proposed model, the drop simulation of finite element model of single-leg landing gear is performed on proposed soil models with different particle diameters. The impact load delivered to the strut of the lander is compared to test results.

Plume Behavior Study of Apollo Lunar Module Descent Engine Using Computational Fluid Dynamics (전산유체역학을 이용한 아폴로 달착륙선 하강엔진의 플룸 거동 연구)

  • Choi, Wook;Lee, Kyun Ho;Myong, Rho Shin
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.45 no.9
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    • pp.766-774
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    • 2017
  • When a plume flow exhausted from a lunar lander descent engine impinges on the lunar surface, regolith particles on the lunar surface will be dispersed due to a plume-surface interaction. If the dispersed particles collide with the lunar lander, some adverse effects such as a performance degradation can be caused. Thus, this study tried to predict the plume flow behaviors using the CFD methods. A nozzle inside region was analyzed by a continuum flow model based on the Navier-Stokes equations while the plume behaviors of the outside nozzle was performed by comparing and analyzing the individual results using the continuum flow model and the DSMC method. As a result, it was possible to establish an optimum procedure of the plume analysis for the lunar lander descent engine in the vacuum condition. In the future, it is expected to utilize the present results for the development of the Korean lunar lander.

Vacuum Pressure Effect on Thermal Conductivity of KLS-1 (진공압에 따른 한국형 인공월면토(KLS-1)의 열전도도 평가)

  • Jin, Hyunwoo;Lee, Jangguen;Ryu, Byung Hyun;Shin, Hyu-Soung;Chung, Taeil
    • Journal of the Korean Geotechnical Society
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    • v.37 no.8
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    • pp.51-58
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    • 2021
  • South Korea, as the 10th country to join the Artemis program led by NASA, is actively supporting various researches related to the lunar exploration. In particular, the utilization of water as a resource in the Moon has been focused since it was discovered that ice exists at the lunar pole as a form of frozen soil. Information on the thermal conductivity of lunar regolith can be used to estimate the existence for ice water extraction by thermal mining. In this study, the vacuum pressure effect on thermal conductivity of KLS-1 was investigated with a DTVC (Dusty Thermal Vacuum Chamber). The reliability of KLS-1 was reconfirmed through comparison with thermal conductivity of known standard lunar regolith simulants such as JSC-1A. An empirical equation to assess thermal conductivity considering dry unit weight and vacuum pressure was proposed. The results from this study can be implemented to simulate lunar cryogenic environment using the DTVC.

Lumped System Analysis on the Lunar Surface Temperature Using the Bottom Conductive Heat Flux Model (달 표면온도 예측을 위한 집중계 해석방법과 하부 열유속 모델의 적용)

  • Kim, Taig Young
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.47 no.1
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    • pp.66-74
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    • 2019
  • Instead of securing thermophysical properties throughout the entire lunar surface, a theoretical method to predict the lunar surface temperature accurately using improved Lumped System Model (LSM) was developed. Based on the recently published research, thermal mass per unit area at the top regolith layer is assumed uniform. The function of bottom conductive heat flux was introduced under the theoretical background. The LSM temperature prediction agrees well with the DLRE measurement except for dusk, dawn and high latitude region where the solar irradiation is weak. The relative large temperature discrepancy in such region is caused by the limit of the bottom conductive heat flux model. The surface temperature map of the moon generated by the LSM method is similar to the DLRE measurement except for the anomalous temperature zones where surface topography and thermophysical properties appear in highly uneven.

Study of the Lunar Regolith using Multi-band Polarimetric Observations

  • Kim, Sungsoo S.;Jung, Minsup;Sim, ChaeKyung;Kim, Il-Hoon;Min, Kyoung Wook;Jin, Ho
    • The Bulletin of The Korean Astronomical Society
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    • v.39 no.1
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    • pp.65.2-65.2
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    • 2014
  • 태양 빛이 달 표면에서 반사될 때는 일부가 편광 된다. 이러한 월면 편광은 달 표토층 입자의 크기와 성분을 알려주는 중요한 정보이나, 이전의 달 궤도선에서는 한 번도 탐사되지 않았다. 또한 달 탐사임무에 있어 틈새시장인 월면 특이지역 연구에도 편광이 중요한 기초자료를 제공한다는 사실이 최근 밝혀졌다. 이에 본 연구진은 한국형 달 탐사선을 위한 우리나라 고유의 창의적 과학 임무 중 하나로 <월면 다파장 편광 탐사>를 제안하며, 이러한 탐사에 필요한 기초연구 및 선행연구를 수행하고 있다. 본 발표에서는 우리가 수행한 지상으로부터의 다파장 편광 관측 결과를 보고하고, 최근 시작한 랩실험과 컴퓨터 시뮬레이션 실험에 대해 소개할 것이다.

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Space Planet Exploration Rover Climbing Test Site Design (우주 행성 탐사 로버 등판 시험장 설계)

  • Byung-Hyun Ryu
    • Journal of the Korean Geosynthetics Society
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    • v.22 no.4
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    • pp.1-8
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    • 2023
  • Space exploration is at the forefront of human scientific endeavors, and planetary exploration rovers play a critical role in studying planetary surfaces. Rover performance is especially vital for safely navigating steep terrain and delicate landscapes found on planets like Mars and the Moon. This paper offers a comprehensive overview of a landing testbed designed to simulate challenging extraterrestrial terrain and loose regolith. The paper briefly outlines lunar crater region topographical features and highlights the importance of these simulations in rover testing. It then explores previous landing testbed developments and describes the design process for a landing testbed to be installed in the dirty thermal vacuum chamber at the Korea Institute of Civil Engineering and Building Technology. Once realized, this proposed landing testbed will enable precise evaluations of rover mobility and exploration capabilities under lunar-like conditions, including high vacuum and extreme temperatures.

Assessment of the Coupled Electric-Thermal Numerical Model for Microwave Sintering of KLS-1 (한국형 인공월면토(KLS-1) 마이크로파 소결을 위한 전기장-열 연계해석 모델 평가)

  • Jin, Hyunwoo;Go, Gyu-Hyun;Lee, Jangguen;Shin, Hyu-Soung;Kim, Young-Jae
    • Journal of the Korean Geotechnical Society
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    • v.38 no.5
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    • pp.35-46
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    • 2022
  • The in-situ resource utilization (ISRU) for sustainable lunar surface and deep space explorations has recently gained attention. Also, research on the development of construction material preparation technology using lunar regolith is in progress. Microwave sintering technology for construction material preparation does not require a binder and is energy efficient. This study applies microwave sintering technology to KLS-1, a Korean lunar simulant. It is crucial to secure the homogeneity to produce a sintered specimen for construction material. Therefore, understanding the interactions between microwaves, cavities, and raw materials is required. Using a numerical model in terms of efficient assessment of several cases and establishment of equipment operating conditions is a very efficient approach. Therefore, this study also proposes and verifies a coupled electric-thermal numerical model through cross-validation and comparison with experimental results. The numerical model proposed in this study will be used to present an efficient method for producing construction material using microwave sintering technology.