• KSCE Journal of Civil and Environmental Engineering Research
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• v.40 no.1
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• pp.51-58
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• 2020

As interest in lunar exploration increases, studies on lunar surface environment simulation including a lunar soil simulant are being conducted. One of the problems when creating a vacuum environment with lunar soil is that it takes long time to reach high vacuum due to outgas from the soil. Most of the outgas is water, and the time to reach high vacuum can be significantly reduced by a pretreatment process that removes moisture adhering to the surface of the lunar soil before putting soil into a vacuum chamber. The existing soil drying methods were examined to determine how these methods were effective to remove moisture from the lunar simulant soil. Drying experiments of lunar soil samples were carried out using a dry oven, a microwave oven, direct heating method and a vacuum oven, and the results of the drying experiment were presented. Drying soil at 110℃ using a dry oven and drying soil by a microwave oven were not enough to remove moisture, and vacuum oven drying method and direct heating drying method at more than 200℃ were effective in water removal.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.42 no.12
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• pp.1037-1044
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• 2014

In this study, we designed a drop test system considering lunar surface environment and tested landing gear of experimental lunar lander. The lunar lander would be landed at soil place for soft landing. When the lunar lander touches down, the acceleration of the lander is largely affected by mechanical characteristics of the lunar soil. Accordingly, a drop test using lunar soil is needed to verify the performance of the lunar landing gear. Because the lunar soil is not available generally, we developed a lunar simulant KAUMLS(Korea Aerospace University Mechanical Luna Simulant) based on mechanical properties of the lunar soil of NASA's LUNA PROJECT. In addition, drop tests on steel plate and dry sand are performed to evaluate impact characteristics by the surface environment.

• Journal of the Korean Geotechnical Society
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• v.32 no.11
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• pp.97-108
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• 2016

Lunar rover plays an important role in lunar exploration. Especially, performance of rover wheel related to interaction with lunar soil is of great importance when it comes to optimization of rover's configuration. In this study, in order to investigate the motion performance of lunar rover's wheel on Korean Lunar Soil Simulant (KLS-1), a single wheel testbed was developed and used to carry out a series of experiments with two kinds of wheel with grousers and without grousers which were used to perform the experiments. Wheel traction performance was evaluated by using traction parameters such as drawbar pull, torque and sinkage correlated with slip ratio. The results showed that the single wheel testbed was suitable for evaluation of the performance of wheel and rover wheel with grousers which was likely to have higher traction performance than that without grousers in Korean Lunar soil simulant. The experimental results could be utilized in verification of the optimum wheel design and effectiveness of wheel traction for Korean lunar rover.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.39 no.2
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• pp.345-349
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• 2019

The National Aeronautics and Space Administration (NASA) has long been studying the essential elements of manned planetary exploration and has held several international challenges to encourage the research works related to it. One of them was the NASA Centennial Challenge Programs which started in 2015. Following the second in 2017, the third is currently going on in 2019. Participating "3D-Printed Habitat Challenge", one of the challenges in the second program, this research team designed and developed the 3D printer extruding module for the Lunar Simulant (Korea Hanyang Lunar Simulant-1; KOHLS-1) and the polymer. For optimizing the modul, a cylindrical specimen of ${\varnothing}150{\times}300mm^3$ volume and a specimen of $200{\times}100{\times}650mm^3$ volume were manufactured and their compressive and flexural strengths were tested. The findings can help automatize the space construction in the future.

• Journal of Astronomy and Space Sciences
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• v.38 no.4
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• pp.237-250
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• 2021

A rover is a planetary surface exploration device designed to move across the ground on a planet or a planetary-like body. Exploration rovers are increasingly becoming a vital part of the search for scientific evidence and discoveries on a planetary satellite of the Sun, such as the Moon or Mars. Reliable behavior and predictable locomotion of a rover is important. Understanding soil behavior and its interaction with rover wheels-the terramechanics-is of great importance in rover exploration performance. Up to now, many researchers have adopted Bekker's semiempirical model to predict rover wheelsoil interaction, which is based on the assumption that soil is deformable when a pressure is applied to it. Despite this basic assumption of the model, the pressure-sinkage relation is not fully understood, and it continues to present challenges for rover designers. This article presents a new pressure-sinkage model based on dimensional analysis (DA) and results of bevameter tests. DA was applied to the test results in order to propose a new pressure-sinkage model by reducing physical quantitative parameters. As part of the work, a new bevameter was designed and built so that it could be successfully used to obtain a proper pressure-sinkage relation of Korean Lunar Soil Simulant (KLS-1). The new pressure-sinkage model was constructed by using three different sizes of flat plate diameters of the bevameter. The newly proposed model was compared successfully with other models for validation purposes.

• Journal of the Korean Geotechnical Society
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• v.39 no.6
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• pp.13-19
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• 2023

Lunar ice is a resource available for future human exploration in deep space and long-term extraterrestrial habitat. However, the origin and nature of lunar ice remains unclear. In addition to remote sensing, international space agencies are competitively planning and conducting missions for lunar surface exploration to determine the existence and resource extent of lunar ice. If a sufficient amount of lunar ice is confirmed, its future in-situ resource utilization is expected to be greatly beneficial. However, due to ice extraction, settlement may occur, which should be taken into account from a geotechnical engineering perspective. Herein, experimental investigations of the potential settlement caused by lunar ice extraction were conducted and different textures of lunar ice were simulated. Consequently, it was confirmed that significant settlement occurs even at the initial water content of ~10% in lunar regolith simulant-ice-mixed soil.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.4
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• pp.693-703
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• 2017

Rover wheel's mobility depends on soil's condition and wheel's design. The purpose of this study is to evaluate the effect of soil conditions, which are Jumunjin sand and Korean lunar soil simulant (KLS-1), on wheel's motion performance. The experiments were performed by using a single wheel testbed with a wheel which grouser height is 15mm on Jumunjin sand and KLS-1, respectively. Also the influence of grouser length to wheel's mobility performance was studied. The experimental results of torque, drawbar pull and sinkage relating to slip ratio were discussed and analyzed to evaluate wheel's motion performance. Results showed wheel moving on KLS-1 has high performance than Jumunjin sand. Wheel's mobility performance was influenced by soil's properties of cohesion and frictional angle. In addition, wheel's performance of drawbar pull and Torque increased with the increasing of grouser length.