• Title/Summary/Keyword: 지구 저궤도

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Analyses for Re-entry Event and Survival characteristics according to Characters of Re-entering Space Objects (지구 재진입체의 특성에 따른 재진입사례 및 생존특성 분석)

  • Jeong, Soon-Woo;Min, Chan-Oh;Lee, Dae-Woo;Cho, Kyeum-Rae
    • Journal of Advanced Navigation Technology
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    • v.17 no.1
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    • pp.80-89
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    • 2013
  • The amount of object which reenter the Earth's atmosphere has been increasing after the Sputnik I launch in October 1957. Most of reentry objects were incinerated by aerodynamic heating so they hardly survive. But they may incur casualties and widespread property damages if they survive and fall to surface. The amount of reentry objects, such as Satellite, Rocket Booster, Pressure Tank, ISS shows continued growth as byproduct of space activities. Most of the re-entry objects are incinerated at between altitude of 50km~80km and 10%~40% of the objects are surviving and falling to the ground. Therefore, this paper try to piece together the reentry event and analysis the survival characteristics of re-entry object.

Analysis of Development Requirements on Simulated Ground Test Module for Underwater Residential Facilities (해저거주시설 모사 지상실험모듈 개발 요구사항 분석)

  • Joohee Lee;Younkyu Kim;Jongwon Lee
    • Journal of Space Technology and Applications
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    • v.2 no.3
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    • pp.206-220
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    • 2022
  • There are various systems that allow humans to safely maintain their space exploration missions and lives in completely different environments, such as the International Space Station, the Moon (the closest celestial body to Earth), and Mars (the only planet in the solar system for manned mission in the 2030s). Among them, when it comes to maintaining the basic breathing of humans, the human life support air management system is a key device system. Such an air management system can be used not only for space exploration but also for undersea bases and submarines on Earth where humans reside. The air management system basically consists of an oxygen generation system, a carbon dioxide removal system, and a harmful substance removal system. In this paper, in order to develop an air management system that can be used in an underwater residential platform, the development requirements of a ground test module to be used as an experimental facility were analyzed.

SATELLITE OPERATION DESIGN FOR ASSESSING MTF PERFORMANCE OF EARTH OBSERVATION SATELLITE USING STELLAR SOURCES (별을 이용한 지구 관측 위성의 MTF 성능 분석을 위한 위성 운영 설계)

  • Kim, Hee-Seob;Chung, Dae-Won;Choi, Hae-Jin
    • Journal of Astronomy and Space Sciences
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    • v.24 no.4
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    • pp.379-388
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    • 2007
  • Modulation Transfer Function (MTF) of satellite image is an important performance index in satellite image applications. Therefore MTF performance is assessed using satellite image for the ground target during LEOP phase after launch. But the MTF performance assessment using the ground target can be affected by imaging conditions such as cloud and weather. In this paper system requirements and satellite operation for assessing MTF performance of satellite image using stellar sources are proposed. Satellite capability in collecting stellar sources using the satellite which is designed for earth observation and satellite image usefulness for assessing MTF performances were analyzed. The proposed approach will be useful to assess MTF performance of earth observation satellite in lower earth orbit.

Analysis of the Detection Time of Distress Signal for LEOSAR and MEOSAR Systems (LEOSAR 및 MEOSAR 시스템의 조난신호 탐지시간 해석)

  • Lim, Sang-Seok
    • Journal of Advanced Navigation Technology
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    • v.10 no.4
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    • pp.377-384
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    • 2006
  • In this paper the detection time of the distress signal for the satellite-based search and rescue (SAR) system is evaluated. Present LEOSAR system in operation employs a few Low-altitude Earth Orbit (LEO) satellites and hence provides poor and local coverage availability. This results in a considerably long waiting time for a distress beacon to be detected by a rescue mission control center. One can expect that the detection time of the distress signal will be significantly reduced if the proposed MEOSAR system, which is based on the Medium-altitude Earth Orbit (MEO) satellites, is implemented. Taking into account the influence of the obstacles on the beacon signal, simulations are carried out to evaluate the detection time of distress signals for the LEOSAR and MEOSAR systems and the corresponding results are analyzed.

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Thermal Pointing Error Analysis of Satellite (인공위성 열지향오차 해석)

  • Kim, Seon-Won;Kim, Jin-Hui;Lee, Jang-Jun;Hwang, Do-Sun
    • Journal of Satellite, Information and Communications
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    • v.2 no.1
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    • pp.21-26
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    • 2007
  • LEO Satellite that observes earth with optical camera or synthetic aperture radar is placed at hundreds of kilometers altitude and undergoes severe thermal load. The thermal deformation of structure by the thermal load makes payload not to point toward wanted ground position. The payload pointing direction change by thermal distortion is called thermal pointing error. This is carried out by 3 steps that are thermal analysis, temperature conversion and structural analysis. In this paper, the possibility of successful mission through thermal pointing error analysis is described.

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A Study on the Optical Bench for LEO Earth Observation Satellite (저궤도 지구관측위성의 광학탑재체 지지구조물 설계 연구)

  • Kim, Kyung-Won;Kim, Jin-Hee;Rhee, Ju-Hun;Jin, Ik-Min;Kim, Jong-Wo
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2005.05a
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    • pp.805-808
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    • 2005
  • This paper is a study on an optical bench satisfying stiffness and thermal pointing error requirements for LEO earth observation satellite. According to shape and stiffness requirements, optical bench type 1 is designed. Because type 1 does not satisfy the thermal pointing error requirement, an optical bench type 2 is suggested. Although the type 2 has better results than type 1, it still does not meet the thermal pointing error requirement. Using the results of optical bench type 1&2, the optical bench type 3 is finally designed, which satisfies both the stiffness and thermal pointing error requirements.

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A Simplified Series-Parallel Structure for the RPPT(Regulated Peak Power Tracking) System (RPPT 시스템을 위한 단순화된 직.병렬 구조)

  • Yang, J.H.;Bae, H.S.;Lee, J.H.;Cho, B.H.
    • Proceedings of the KIPE Conference
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    • 2007.11a
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    • pp.72-74
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    • 2007
  • 기존에 사용된 저궤도 인공위성 전력계 시스템을 분석하고, 시스템의 효율을 향상시키는 단순화된 직병렬 구조를 제안한다. 인공위성이 지구를 공전하는 동안 상황에 따라 변화하는 제안된 구조의 동작을 모드로 분류하고, 제안한 시스템을 안정적으로 운용하기 위해 시스템 운용 알고리즘을 제안한다. 모의 실험을 통하여 기존의 직렬구조와 제안된 구조의 효율을 비교 한다. 제안된 단순화된 직병렬 구조의 안정적인 동작을 검증하기 위해, 200W급 태양전지와 100W급 전력조절기 두 모듈을 병렬로 구성하여 실험하였다.

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회원사 탐방-21세기의 선택-항공우주산업과 기술을 선도하는 항공우주연구소를 찾아서

  • The Korea Society of Space Technology
    • Satellite Communications and Space Industry
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    • v.2 no.2
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    • pp.125-130
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    • 1994
  • 지난 4월 25일 종합과학기술심의회에서 국책사업으로 "다목적 실용위성 개발사업"의 기본계획, 개발체계, 정부부처간 역할분담 등 세부계획이 심의.의결을 거쳐 확정되었다. 이 사업은 오는 97년까지 정부지원 1천4백15억원 민간출연 2백35억원을 포함 총 1천6백50억원을 투입하여 해양탐사.환경관측.과학실험 등에 활용할 수 있는 지구저궤도용 다목적 실용위성을 개발 발사하는 것을 목표로 추진되고 있다. 다목적 실용위성 개발사업은 추진 체계 및 일정이 최종 확정됨에 따라 항공우주연구소를 사업총괄 주관기관으로 오는 9월부터 본격적으로 착수될 전망이다. 인공위성연구센터가 우리별 1호와 2호를 성공적으로 발사하여 우리나라 위성분야의 새로운 장을 열어 놓은데 이어 다목적 실용위성 개발사업이 구체화 됨에 따라 사업의 총괄 주관기관으로 선정된 항공우주연구소를 탐방하여 홍재학소장과 대담을 통하여 구체적인 사업추진 계획과 전망을 조명함은 물론 우주 첨단과학 기술의 산실인 항공우주연구소의 활동상황과 앞으로의 포부를 들어 보았다.

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Fuel Consumption Estimation for Atmospheric Drag Using LEO Perturbation Analysis (섭동해석을 이용한 저궤도 위성의 대기저항 보정용 연료 소모량 예측)

  • Jung, Do-Hee;Song, Yong-Kyu
    • Journal of Advanced Navigation Technology
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    • v.3 no.2
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    • pp.147-155
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    • 1999
  • In this work variations of orbital parameters are derived from the perturbation equations under Earth oblateness and atmospheric drag. A simple and effective scheme is proposed to compute the required delta v and fuel consumption to compensate for atmospheric drag. The scheme is applied to KOMPSAT example.

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Mission Design for a Lunar Orbiter Launched by KSLV-II (한국형발사체를 사용한 달궤도선의 임무 설계)

  • Song, Eun-Jung;Park, Chang-Su;Cho, Sang-Bum;Roh, Woong-Rae
    • Aerospace Engineering and Technology
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    • v.8 no.1
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    • pp.108-116
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    • 2009
  • This paper considers the trajectory design problem for a lunar orbiter when launched by KSLV-II. KSLV-II puts its kick motor stage and lunar orbiter into a low earth orbit, and then the kick motor stage performed the translunar injection. To simulate more realistic situations, TLI (Trans-Lunar Injection) and LOI (Lunar Orbit Injection) maneuvers are modeled as finite burns. The feasibility of the lunar mission by KSLV-II are confirmed by the numerical results that show the reasonable required-velocity and propellant usage.

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