• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2012.05a
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• pp.42-45
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• 2012

As a basic research for the development of Korean lunar lander, propulsion system development for ground test is in progress. Design target is 220 N in ground thrust at 130 g/s flow rate, 200 psi chamber pressure. For the performance improvement, two type injector and catalyst bed was designed. For ground test, thrust measurement system using LM guide was developed and test was performed. The result shows 214.1 N thrust in atmosphere condition at 126.6 g/s flow rate.

• Journal of the Korean GEO-environmental Society
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• v.23 no.10
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• pp.21-31
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• 2022

Prospecting ice on Moon requires drilling systems to obtain subsurface samples and measure composition of ice deposits. Landers and rovers need to be equipped with drilling equipment in order to analyze the ice and subsurface resources located at the poles of Moon. These devices must be small, lightweight, low-power, highly efficient and high-performance units in order to function properly under the extreme conditions of the lunar environment. Researchers have developed a prototype drilling apparatus that is able to operate in atmospheric and cold environments. Newly developed drilling system in Korea, which is capable of performing not only sampling but also subsurface investigation, is introduced.

• The Bulletin of The Korean Astronomical Society
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• v.46 no.2
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• pp.78.1-78.1
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• 2021

A Lunar observatory not only provides ideas and experiences for space settlements from the Moon to Mars, but also puts the telescope in an optimal position to compete with space telescopes. Earth observation on the Moon's surface has the advantage of no atmospheric scattering or light pollution and is a stable fuel-free observation platform, allowing all longitude and latitude of the Earth to be observed for a month. Observing the entire globe with a single observation instrument, which has never been attempted before, and calculating the global albedo will significantly help predict the weather and climate change. Spectropolarimetric observations can reveal the physical and chemical properties of the Earth's atmosphere, track the global distribution and migration path of aerosols and air pollutants, and can also help detect very small space debris of which the risk has increased recently. In addition, the zodiacal light, which is difficult to observe from Earth, is very easy to observe from the lunar observatory, so it will be an opportunity to reveal the origin of the solar system and take a step closer to understanding the exoplanet system. In conclusion, building and developing a lunar observatory will be a groundbreaking study to become the world's leader that we have never tried before as a first step in expanding human experience and intelligence.

• Journal of Positioning, Navigation, and Timing
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• v.12 no.4
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• pp.335-342
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• 2023

Lunar Navigation Satellite System refers to a constellation of satellite providing PNT services on the moon. LNSS consists of main satellite and navigation satellites. Navigation satellites orbiting around the moon and a main satellite moves the area between the moon and the L2 point. The navigation satellite performs the same role as the Earth's GNSS satellite, and the main satellite communicates with the Earth for time synchronization. Due to the effect of the non-uniform shape of the moon, it is necessary to focus on the influence of the lunar gravitational field when designing the orbit simulation for navigation satellite. Since the main satellite is farther away from the moon than the navigation satellite, both the earth's gravity and the moon's gravity must be considered simultaneously when designing the orbit simulation for main satellite. Therefore, the main satellite orbit simulation must be designed through the three-body problem between the Earth, the moon, and the main satellite. In this paper, the orbit simulation tool for main satellite and navigation satellite required for LNSS was designed. The orbit simulation considers the environment characteristics of the moon. As a result of comparing long-term data (180 days) with the commercial program GMAT, it was confirmed that there was an error of about 1 m.

• Journal of Astronomy and Space Sciences
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• v.40 no.4
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• pp.131-148
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• 2023

Lunar permanently shadowed regions (PSRs) never see direct sunlight and are illuminated only by secondary illumination - light reflected from nearby topography. The ShadowCam imaging experiment onboard the Korea Pathfinder Lunar Orbiter is acquiring images of these PSRs. We characterize and discuss the nature of secondary illumination for the Shackleton PSR from ShadowCam radiance-calibrated images. We also use modeling to understand the magnitude and direction of the secondary illumination. Results from our analysis highlight the non-homogeneous, dynamic, and complex nature of PSR secondary lighting. Knowledge of the direction of the secondary illumination is crucial for reli-able interpretation of contrasts observed in ShadowCam images. This preliminary analysis of the floor of Shackleton crater from images acquired over multiple secondary illumination conditions does not reveal indications of exposed surface ice, even though temperatures are constantly below 110K.

• Journal of Space Technology and Applications
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• v.3 no.4
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• pp.373-384
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• 2023

Initiated as Korea's inaugural space exploration endeavor, the lunar exploration development project has resulted not only the Danuri lunar orbiter but also payloads designed to achieve mission objectives and the associated Korea Pathfinder Lunar Orbiter (KPLO) Deep-space Ground System for the operation and control of the Danuri. Scientific data gathered by four scientific payloads, developed by domestic institutions and installed on board the Danuri, will be publicly available starting January 2024. To facilitate this, the first-ever Korean space exploration scientific data management and public release system, KARI Planetary Data System (KPDS), has been developed. This paper provides details on the configuration and functions of the established KPDS website.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.39 no.6
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• pp.801-809
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• 2019

NASA's lunar polar exploration mission in 2009 confirmed the presence of ice-layer in the permanently shadowed regions (PSR) of the moon. Since then, studies have been actively conducted to evaluate the ground characteristics for exploring the ice-layer in the polar regions of the Moon. In this study, transient heat transfer analysis for the lunar ground was conducted to predict the ground's temperature that varies with the time and location. As a result of the numerical analysis, it was confirmed that the temperature under the lunar ground converged to below the ice sublimation reference temperature (≒112 K) at above 86° latitude. This model enabled us to identify the regions where there is a high possibility of ice being buried. Besides, we found that the ice-layer in the shallow region, where the temperature deviation is significant, makes ground temperature distribution heterogeneous. Lastly, this study suggested the maximum allowable frictional heat of a drill bit that can preserve the phase of buried ice.

• Journal of the Korean earth science society
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• v.41 no.2
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• pp.194-207
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• 2020

The purpose of this study is to identify the types and characteristics of elementary school pre-service teachers revealed in the process of resolving the change of lunar phases, which emphasizes the context of actual observation, and to provide suggestions for areas to be considered in the elementary school teacher training program. To this end, we analyzed the 30 pre-service teachers' explaining the observable lunar phases, and the main research results are as follows. First, the phase change of the moon was often explained by introducing the timetable for each phase of the moon rather than based on observation of the phenomenon and scientific reasoning. Second, an alternative concept of the type that the moon is invisible when the sun rises or that the moon can always be observed has been identified. Third, there was a case of explaining that the time and orientation for observing the moon can be observed regardless of the position of the sun or when observing the sun. Also, the date of observing the moon was assumed to be approached by assuming the lunar calendar. Based on the above results, pedagogical implications were discussed.

• Korean Journal of Remote Sensing
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• v.35 no.2
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• pp.265-278
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• 2019

Visible Infrared Imaging Radiometer Suite (VIIRS) Day/Night Band (DNB) data help to enable rapid emergency responses through detection of the artificial and natural disasters occurring at night. The DNB data without correction of lunar irradiance effect distributed by Korea Ocean Science Center (KOSC) has advantage for rapid change detection because of direct receiving. In this study, radiance differences according to the phase of the moon was analyzed for urban and mountain areas in Korean Peninsula using the DNB data directly receiving to KOSC. Lunar irradiance correction algorithm was proposed for the change detection. Relative correction was performed by regression analysis between the selected pixels considering the land cover classification in the reference DNB image during the new moon and the input DNB image. As a result of daily difference image analysis, the brightness value change in urban area and mountain area was ${\pm}30$ radiance and below ${\pm}1$ radiance respectively. The object based change detection was performed after the extraction of the main object of interest based on the average image of time series data in order to reduce the matching and geometric error between DNB images. The changes in brightness occurring in mountainous areas were effectively detected after the calibration of lunar irradiance effect, and it showed that the developed technology could be used for real time change detection.

• 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.