• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.05a
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• pp.155-158
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• 2008

Development of Moon Explorer-1 (orbiter) is supposed to be commenced in 2017 and launched in 2020. In case of Moon Explorer-2 (lander), it would be slated to start in 2021 and launch in 2025. For this reason it is taken for granted to investigate a fundamental propulsion system for a Moon Explorer. In this paper conceptual feasibility and comparison studies are proposed for the propulsion system applicable to a Moon Explorer. Availability of monopropellant/bipropellant/electric propulsion system is compared and analysed as well with precedents overseas. As a result possible candidates for a Moon Explorer propulsion system are suggested.

• Journal of the Korean Society of Propulsion Engineers
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• v.13 no.4
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• pp.22-29
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• 2009

Development of Moon Explorer-1 (orbiter) is supposed to be commenced in 2017 and launched in 2020. In case of Moon Explorer-2 (lander), it would be slated to start in 2021 and launch in 2025. In this paper conceptual feasibility studies are conducted for the propulsion system applicable to a Moon Explorer. In the first place the availability of monopropellant/bipropellant/electric propulsion system is examined with domestic as well as overseas precedents. Secondly ${\Delta}V$ is estimated by the mission analysis and the propellant budget is calculated accordingly. Subsequently feasibility of a chemical propulsion system for a Moon Explorer is evaluated.

• Current Industrial and Technological Trends in Aerospace
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• v.6 no.1
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• pp.74-81
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• 2008

In this paper, the technical trends of the lunar exploration were studied by investigating the objectives of the mission of the recent lunar orbiters. The payloads of the lunar orbiter launched and planned since 1990 are rearranged and analyzed according to the objectives of the mission and the performance. In the future, it will be used to define the objectives of the mission and to make a plan for developing the payloads of the domestic lunar orbiter.

• Aerospace Engineering and Technology
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• v.7 no.1
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• pp.91-98
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• 2008

Since the 1st space race between the United States and Soviet Union during the 1960s, we are competing 2nd space race to occupy the Lunar territory. Since the United States announced to construct the Lunar Base by the end of 2020, ED, Japan, and China launched Lunar explorers successfully. Even India is planning to launch a Lunar explorer in 2008. Korean government also announced that the Korea will launch first Lunar explorer in 2020. In this research Lunar mission trajectory design which will be fundamental data for Lunar mission with variable low thrust and Lunar mission trajectory which has a similar mission specification to SMART-1 are presented.

• Current Industrial and Technological Trends in Aerospace
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• v.7 no.1
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• pp.56-67
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• 2009

From 1990s, the lunar exploration programs, suspended over 20 years after the project Apollo's first successful human landing on the Moon in 1969, have been restarted according to a revived interest in Moon. In recent, several nations progress their own lunar exploration program successfully. In this report, to investigate the technical trends of the onboard propulsion system for the lunar orbiter, technical features related to the performance of the propulsion system of the lunar orbiters developed since 1990 are surveyed. In the future, it is expected that this technical report can provide a fundamental guideline for selecting a proper type of the onboard propulsion system for the domestic lunar orbiter.

• Journal of the Korean Society of Propulsion Engineers
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• v.15 no.1
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• pp.90-101
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• 2011

From 1990s, the lunar exploration programs, suspended over 20 years after the project Apollo's first successful human landing on the Moon in 1969, have been restarted according to a revived interest in Moon. In recent, several nations progress their own lunar exploration program successfully. In this report, to investigate the technical trends of the onboard propulsion system for the lunar orbiter, technical features related to the performance of the propulsion system of the lunar orbiters developed since 1990 are surveyed. In the future, it is expected that this technical report can provide a fundamental guideline for selecting a proper type of the onboard propulsion system for the domestic lunar orbiter.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.9
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• pp.875-881
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• 2010

During the lunar mission, spacecraft are subject to various unexpected disturbance sources such as third body attraction, solar pressure and operating impulsive maneuver error. Therefore, efficient trajectory correction maneuver (TCM) strategy must be required to follow the designed mission trajectory. In the early days of space exploration, the mission trajectory has been designed by using patched conic approach based on two-body dynamics for the lunar mission. Thus the TCM based on two-body dynamics has been usually adopted. However, with the advanced in computing power, the mission trajectory based on three-body dynamics is attempted recently. Thus, these approaches based on two-body dynamics are essentially different from real environment and large amount of energy for the TCM is required. In this work, we study the trajectory correction maneuver based on three-body dynamics.

• Current Industrial and Technological Trends in Aerospace
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• v.5 no.2
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• pp.11-19
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• 2007

80년대 냉전 종식이후 세계 각국의 우주기술 추진방향이 군수분야에서 상업분야로 전환되었다. 특히 90년대 이후는 정보화 시대의 핵심 산업으로 소형의 저궤도 위성을 이용한 이동통신, 원격탐사 분야를 중심으로 미국 주도하에 급신장하였다. 미국 및 러시아 등 우주개발 선진국과 일본, 중국, 프랑스, 영국, 독일, 인도 등 우주기술 선점국 들은 대부분 위성독자개발기술을 보유하고 있으며, 최근의 우주개발은 2004년 미국의 부시 대통령이 새로운 우주정책을 발표한 후 달탐사 분야에서 유럽, 일본, 중국, 인도 등이 국가적 자존심을 걸고 경쟁하고 있다. 이러한 상황에서 우리나라의 최초의 위성인 우리별 위성을 개발하는데 커다란 영향을 끼친 우주 선진국 중 하나인 영국의 우주개발 동향을 조사하여 우리가 본 받을만한 국가로 벤치마킹 하는 것은 뜻 깊은 일이라고 생각한다.

• The Optical Journal
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• s.142
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• pp.17-22
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• 2012

인공위성 레이저 추적(SLR, Satellite Laser Ranging) 시스템은 레이저를 이용하여 위성까지 거리를 측정하는 가장 정밀한 인공위성 추적 시스템이다. SLR 시스템의 원리는 극초단파의 레이저 빔을 광학 망원경을 통해 발사하여 인공위성에 장착된 레이저 반사경에 의해 반사되어 되돌아오는 레이저 빔의 왕복 비행 시간을 측정함으로써 거리를 구한다. 1964년 발사된 Beacon Explorer-B 위성의 궤도결정을 위해 SLR 기술이 NASA에 의해 처음 사용되었는데, 당시에는 거리측정 오차가 50m 수준이었다. 현재는 전자, 광학 및 제어 기술의 발달에 힘입어 그 오차가 mm 수준으로 크게 향상되어 인공위성 운영, 지구물리, 우주측지 및 우주감시 등 다양한 분야에 활용되고 있다. 미국을 비롯한 우주 선진국은 이미 다수의 SLR 시스템을 구축하여 운영하고 있으며, 현재 전 세계적으로 약 40여 개의 SLR 관측소가 국제레이저추적기구(ILRS, International Laser Ranging Service)에 가입하여 활동하고 있다. 또한 인공위성의 정밀한 거리측정을 위해 레이저 반사경이 장착된 위성 50여 개가 운영중에 있다. 고정밀 지구관측 위성 대부분에 레이저 반사경이 장착돼 있으며 러시아의 GLONASS 항법체계를 구성하는 모든 항법위성에도 레이저 반사경이 장착돼 있다. 또한 유럽우주기구에서 추진하는 갈릴레오 및 중국의 Compass 항법위성도 레이저 반사경이 장착될 예정이다. 최근에는 행성탐사 및 달탐사 우주선에 SLR 시스템의 활용 범위가 확대됨에 따라 SLR 시스템의 국제적 수요가 꾸준히 증가하고 있다. 우리나라의 나로과학위성 및 다목적실용위성 5호에도 레이저 반사경이 장착돼 발사되기 때문에 국내 독자적 레이저추적을 위해서 SLR 시스템 구축이 꾸준히 요구되어 왔다. 한국천문연구원은 2008년부터 SLR 시스템 개발을 추진했다. 2012년 9월에 40cm 크기의 망원경을 지닌 이동형 SLR 시스템 개발을 완료했으며 오는 2015년에는 1m급 고정형 SLR 시스템 개발을 완료할 예정이다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.44 no.8
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• pp.702-709
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• 2016

By means of the our satellite development for the past 20 years, it ensure us to obtain domestic independent development capabilities. In the case of practical-class Low-Earth Orbit(LEO) remote sensing satellites, we become a world-class developer. Furthermore, we acquire the technology to develop domestic-leading geostationary satellites, depending on the mission. Currently, we proceed with the next-generation mid-size satellite development program featuring standard bus for the expansion of the world market and has embarked on the development of lunar orbiter from this year.