• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.231.2-231.2
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• 2012

원격탐사를 위한 지구관측용 전자광학 카메라는 높은 해상도, 넓은 관측 폭 및 높은 선명도를 제공하기 위하여 부피가 크고 무거우며, 큰 전력을 소모하여, 위성본체의 대부분을 차지하도록 개발된다. 그러나, 달 탐사를 위해 달 궤도선이나 달 착륙선에 장착되는 전자광학 카메라는, 고해상도의 고성능을 가지도록 개발되기 보다는, 다기능의 집적도 높은 소형카메라로 개발되는 것이 일반적이다. 이에 따라, 달 탐사용 다기능 전자광학 카메라 개발을 위한 기술검증을 위하여 지상모델이 개발되었다. 본 카메라는 CMOS 센서를 사용하여 컴팩트하게 설계하였고, 스테레오 영상생성을 위해 두 개의 카메라가 동시에 운영되며, 줌 기능을 구현하여 다양한 조건에서도 영상획득이 가능하도록 설계 되었다. 또한 달 궤도선과 착륙선에서 1D 관측 및 2D 관측이 선택적으로 가능하도록 설계되었다. 개발된 지상모델은 실험실에서 수행하는 통상적인 기능 및 성능시험을 수행하였고, 스테레오 영상의 생성기능 등의 검증을 위하여 야외에서 카메라를 정속으로 회전하며 push broom 방식의 1D 촬영모드에 대한 시험을 수행한다. 또한, 항공촬영을 통해 1D 및 2D 촬영을 수행하여, 영상데이터의 처리 및 스테레오 영상데이터 생성 등의 검증 단계를 거친다. 본 논문 발표에서는 다기능의 전자광학 카메라를 지상에서 동작시켜 실제영상을 뽑아내고, 생성된 데이터를 처리하여, 설계된 카메라의 여러 가지 기능들에 대해 검증하는 방법들에 대해 정리 및 발표한다. 즉, 달 궤도에 맞게 설계된 카메라의 노출시간 등을 조절하고, push broom 방식을 모사하기 위하여 카메라를 정속으로 회전시켜 영상을 획득하여 다양한 카메라의 기능을 검증하였다.

• The Journal of the Petrological Society of Korea
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• v.19 no.4
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• pp.245-254
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• 2010

Technology of surface investigation using X-ray is one of widely used technology nowadays. This technique has been numerously used for planetary surface investigations for both orbital and rover scientific instruments. Korea has a plan to send an orbiter and lander to the Moon by the early 2020s. Therefore, the time has come for Korean researchers to develop major scientific instruments and start to do research on basic research for the Moon. Because of this situation, we firstly investigate X-ray technology, which is essential as one of core techniques of planetary remote sensing from the orbit and ground. This paper presents the current status of planetary exploration using X-ray techniques and new development of worldwide X-ray technology which could be adapted for prospective planetary missions.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.22 no.4
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• pp.75-80
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• 2014

A lunar lander demonstrator developed for the purpose of demonstrating lunar landing technologies recently in Korea. The thruster control system of the lunar lander demonstrator adopted the main thrusters for altitude control and the reaction thrusters for attitude control. In this paper, we propose a path tracking controller base on Euler angles. The control signals of the controller are of continuous type. And Pulse Width Modulator(PWM) is adopted to provide On/Off signals. We perform MATLAB simulation for evaluating the path tracking performance and the final landing velocity of the lunar lander demonstrator.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.19 no.4
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• pp.37-43
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• 2011

Lunar exploration program has been prepared with the aim of launch in the 2020's. As part of it, a lunar lander demonstrator has been developed which is the model for verifying all the system, such as structure, propulsion and control system before launch to deep space. After verifying all the system, the demonstrator will be evaluated by flight test. This paper deals with path tracking controller based on thrusters for the demonstrator. For this, first we derive equations of motion according to the allocation of thrusters and design the path tracking controller. The signal generated from the controller is continuous so PWPF(Pulse-Width Pulse-Frequency) modulator is adopted for generating on/off signal. Finally MATLAB simulation is performed for evaluating the path tracking ability and the final landing velocity.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.581-584
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• 2010

Korea Aerospace Research Institute (KARI) started preliminary research about the propulsion system for lunar orbiter and moon lander this year in order to prepare korean moon exploration plan of 2020s. The final goal of this study is to develop a prototype propulsion system for lunar exploration and to perform ground landing test using this propulsion system. In this year, preliminary design of propulsion system and 200N class monopropellant thruster have been conducted. In this paper, the trade-off study result and the design concept of the propulsion system for Korean moon exploration will be introduced and preliminary design of propulsion system will be presented.

• 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 Society for Aeronautical & Space Sciences
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• v.41 no.5
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• pp.366-372
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• 2013

Korean lunar explorer will be launched by korean launcher KSLV-2 in the 2020s in accordance with national space development strategy. Korean lunar explorer is composed of two unmanned orbiter and lander and should be developed as small size and light weight within 550kg of launch mass due to launcher's loading capability. A structure of lunar explorer is required to have sufficient stiffness and strength under launch and operational environment as well as to accommodate mission equipment. This paper describes the result of a preliminary study on structural model design for korean lunar explorer.

• 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.39 no.4
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• pp.314-320
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• 2011

In this work, optimization of two-stage shock absorption system for lunar lander has been carried out. Because of complexity of impact phenomena of shock absorption system, a 1-D constitutive model is proposed to describe the behavior of shock absorption system. Quadratic polynomial regression meta-model is constructed by using a commercial software ABAQUS with the proposed 1-D constitutive model, and sequential approximate optimization of two-stage shock absorption system has been carried out along with the constructed meta-model. Through the optimization, it is verified that landing impact force on lunar lander can be considerably reduced by changing the cell size and foil thickness of honeycomb structure in two-stage shock absorption system.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.45 no.8
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• pp.662-670
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• 2017

This paper proposes an optimization-based procedure to determine the parameters of the Apollo guidance law for Korean lunar lander mission. A lunar landing mission is formulated as a trajectory optimization problem to minimize the fuel consumption and the reference trajectory for the lander is obtained by solving the problem in the pre-flight phase. Some parameters of the Apollo guidance, which are coefficients of the polynomial used to define the guidance command, are selected based on the reference trajectory obtained in the pre-flight phase. A case study for the landing guidance of Korean lunar lander mission using the proposed procedure is conducted to demonstrate its effectiveness.