• Journal of Astronomy and Space Sciences
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• v.34 no.2
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• pp.127-138
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• 2017

The current study designs the mission orbit of the lunar CubeSat spacecraft to measure the lunar local magnetic anomaly. To perform this mission, the CubeSat will impact the lunar surface over the Reiner Gamma swirl on the Moon. Orbit analyses are conducted comprising ${\Delta}V$ and error propagation analysis for the CubeSat mission orbit. First, three possible orbit scenarios are presented in terms of the CubeSat's impacting trajectories. For each scenario, it is important to achieve mission objectives with a minimum ${\Delta}V$ since the CubeSat is limited in size and cost. Therefore, the ${\Delta}V$ needed for the CubeSat to maneuver from the initial orbit toward the impacting trajectory is analyzed for each orbit scenario. In addition, error propagation analysis is performed for each scenario to evaluate how initial errors, such as position error, velocity error, and maneuver error, that occur when the CubeSat is separated from the lunar orbiter, eventually affect the final impact position. As a result, the current study adopts a CubeSat release from the circular orbit at 100 km altitude and an impact slope of $15^{\circ}$, among the possible impacting scenarios. For this scenario, the required ${\Delta}V$ is calculated as the result of the ${\Delta}V$ analysis. It can be used to practically make an estimate of this specific mission's fuel budget. In addition, the current study suggests error constraints for ${\Delta}V$ for the mission.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.38 no.6
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• pp.859-865
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• 2018

A construction of infrastructures and base station on the moon could be undertaken by linking with the regions where construction materials and energy could be supplied on site. It is necessary to detect craters on the lunar surface and gather their topological information in advance, which forms permanent shaded regions (PSR) in which rich ice deposits might be available. In this study, an effective method for automatic detection of lunar craters on the moon surface is taken into consideration by employing a latest version of deep-learning algorithm. A training of a deep-learning algorithm is performed by involving the still images of 90000 taken from the LRO orbiter on operation by NASA and the label data involving position and size of partly craters shown in each image. the Faster RCNN algorithm, which is a latest version of deep-learning algorithms, is applied for a deep-learning training. The trained deep-learning code was used for automatic detection of craters which had not been trained. As results, it is shown that a lot of erroneous information for crater's positions and sizes labelled by NASA has been automatically revised and many other craters not labelled has been detected. Therefore, it could be possible to automatically produce regional maps of crater density and topological information on the moon which could be changed through time and should be highly valuable in engineering consideration for lunar construction.

• Journal of Astronomy and Space Sciences
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• v.31 no.2
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• pp.131-140
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• 2014

Lava caves could be useful as outposts for the human exploration of the Moon. Lava caves or lava tubes are formed when the external surface of the lava flows cools more quickly to make a hardened crust over subsurface lava flows. The lava flow eventually ceases and drains out of the tube, leaving an empty space. The frail part of the ceiling of lava tube could collapse to expose the entrance to the lava tubes which is called a pit crater. Several pit craters with the diameter of around 100 meters have been found by analyzing the data of SELENE and LRO lunar missions. It is hard to use these pit craters for outposts since these are too large in scale. In this study, small scale pit craters which are fit for outposts have been investigated using the NAC image data of LROC. Several topographic patterns which are believed to be lunar caves have been found and the similar pit craters of the Earth were compared and analyzed to identify caves. For this analysis, the image data of satellites and aerial photographs are collected and classified to construct a database. Several pit craters analogous to lunar pit craters were derived and a morphological pit crater model was generated using the 3D printer based on this database.

• Journal of The Korean Astronomical Society
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• v.55 no.4
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• pp.87-97
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• 2022

Polarimetric measurements of the lunar surface from lunar orbit soon will be available via Wide-Field Polarimetric Camera (PolCam) onboard the Korea Pathfinder Lunar Orbiter (KPLO), which is planned to be launched in mid 2022. To provide calibration data for the PolCam, we are conducting speckle polarimetric measurements of the nearside of the Moon from the Earth's ground. It appears that speckle imaging of the Moon for scientific purposes has not been attempted before, and there is need for a procedure to create a "lucky image" from a number of observed speckle images. As a first step of obtaining calibration data for the PolCam from the ground, we search for the best sharpness measure for lunar surfaces. We then calculate the minimum number of speckle images and the number of images to be shift-and-added for higher resolution (sharpness) and signal-to-noise ratio.

• Current Industrial and Technological Trends in Aerospace
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• v.6 no.1
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• pp.27-34
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• 2008

One of the purposes of space exploration is to be able to utilize the unlimited natural resources in the universe. For this purpose, plans for lunar and mars bases have been proposed by leading nations. In order to construct bases and search for resources, it is necessary to employ and develop rovers for surface navigation and exploration. With proper knowledge about Lunar surface, technology for lunar rover development can be established without serious obstacles, since robot technology for rover development has been well prepared in Korea. In this paper, lunar rovers and mars rovers developed and planned by other countries as well as the current status of robot technology in Korea have been analyzed.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.6
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• pp.473-480
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• 2013

Researches for various lunar landing technologies are in progress for the lunar exploration program planned for early 2020s in Korea. This paper shows the integrated simulation for safe lunar landing guidance/control system in powered descent phase. Generally, the lunar lander uses on/off(bang-bang) controller to control the RCS jet thrusters instead of proportional controller. In this paper, the on/off controller using phase-plane switching function, and thruster selection algorithm to control sixteen thrusters are applied. Also additional guidance commands are calculated by a proposed fuzzy logic guidance algorithm. The simulation results show that lunar lander can follow a reference trajectory which is generated by optimization method, then land on the surface safely.

• Korean Journal of Mineralogy and Petrology
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• v.34 no.1
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• pp.83-93
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• 2021

NASA has a plan for the Artemis manned lunar mission in 2020. In 2030s, not only America but also other countries are considering to prepare for human to stay on the Moon at least for a month and necessary technology is currently being developed. With this plan, the mostly considered thing is lunar in-situ resource utilization. The most essential resources could be water and oxygen for sustain human life on the Moon. These resources are not supposed to be brought from the Earth, and it is economically sensible if they are obtained from the lunar surface. Because oxygen can be used as both oxidizer and propellent when a rocket departs from a lunar base directly to Mars, technology for extraction method of oxygen resource and its utilization has been being developed worldwide. This paper introduces oxygen distribution on the Moon and major oxygen extraction methods.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.44 no.3
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• pp.218-227
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• 2016

Korean government plans to launch a lunar orbiter and a lander to the Moon by 2020. Before launch these two proves, an experimental lunar orbiter will be launched by 2018 to obtain key space technologies for the lunar exploration. Several payloads equipped in experimental lunar orbiter will monitor the surface of the Moon and will gather science data. Lunar orbiter sends telemetry and receives tele-command from ground using S-band while science data is sent to ground stations using X-band when the visibility is available. Korean deep space network will be mainly used for S and X-band communication with lunar orbiter. Deep Space Network or Universal Space Network can also be used for the S-band during trans-lunar phase when korean deep space network is not available and will be used for the S-band in normal mission orbit as a backup. This paper analyzes a visibility condition based on the combination of various ground antennas and its mask angles according to mission scenario to predict the number of contacts per day and to build an operational scenario for the lunar orbiter.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.7
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• pp.630-637
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• 2019

The scientific, economical and industrial values of the Moon have been increased, as massive ice-water and rare resource were founded from the lunar exploration missions. Korea and other major space agencies in the world are competitively developing the ISRU (In Situ Resource Utilization) technology to secure future lunar resource as well as to construct the lunar base. To prepare for the lunar construction, it is essential to develop the rover based construction spatial information technology to provide a decision-making aided information during the lunar construction process. Thus, this research presented the construction spatial information technology based upon rover's camera system. Specifically, the conceptual design of rover based camera system was designed for acquisition of a rover's navigation image, and lunar terrain and construction images around the rover. The reference architecture of the rover operation system was designed for computation of the lunar construction spatial information. Also, rover's localization and terrain reconstruction methods were introduced considering the characteristics of lunar surface environments. It is necessary to test and validate the conceptual design of the construction spatial information technology. Thus, in the future study, the developed rover and rover operation system will be applied to the lunar terrestrial analogue site for further improvements.

• Proceedings of the Korean Magnestics Society Conference
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• 2015.11a
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• pp.36-36
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• 2015