• Bulletin of the Korean Space Science Society
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• 2009.10a
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• pp.44.4-45
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• 2009

과학기술위성 3호의 주탑재체인 MIRIS (Multi-purpose InfraRed Imaging System) 적외선우주관측카메라의 인증모델이 조립을 마치고 현재 성능시험이 진행 중이다. MIRIS 적외선광학계는 구경 80mm의 광시야(f/2) 굴절식 망원경으로서, 총 5매의 렌즈로 구성되어 있다. 렌즈들은 S-FPL53, S-TIH6, Fused Silica 등의 재료를 사용해 가공되었으며, MIRIS 관측 파장대역($0.9\sim2.0{\mu}m$)에서 투과율이 극대화되도록 반사억제 코팅이 적용되었다. MIRIS 광학계 및 광기계부 설계에 있어서의 주요 고려사항은, 1) 상온에서 조립된 상태에서 발사 시 위성체가 받는 충격과 진동을 견뎌낼 것, 그리고 2) 발사 후 위성 궤도상에서의 복사냉각을 통해 180K로 열수축된 상태에서 최적의 광학성능을 발휘할 것 등이다. 이러한 설계 개념을 바탕으로 MIRIS 광학계를 제작하였으며, 조립된 인증모델은 진동시험 및 열진공시험을 통과하였다. 이 발표에서는 MIRIS 적외선우주관측카메라 광학계의 인증모델 제작 과정과 부품별 시험, 그리고 조립 후 상온 및 저온성능시험 결과에 대하여 논의 한다.

• Journal of the Korean Society of Propulsion Engineers
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• v.2 no.3
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• pp.80-89
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• 1998

Propulsion subsystem transfers KOMPSAT into mission orbit and controls its attitude. Design factor consists of structure safety, electrical circuit design, consumable power estimation of thermal hardwares, damping device design of fuel transient pressure, and system configuration design by considering plume effect from thruster firing. System level analysis should be performed for verification of system design under launch vehicle and orbital environment. Electrical functional test of thermal control hardware, proof pressure test, cleanliness verification test, and internal/external leakage test of fuel feeding system should be carried out for performance estimation of propulsion system. Design and assembly process of propulsion subsystem was depicted and reliability of system was verified by test analysis in this paper.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 1996.11a
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• pp.209-212
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• 1996

접촉발화성 액체추진제를 사용하는 소형 추진기관의 성능을 확인하기 위해 핵심 부품의 상온 성능 시험 및 추진기관 조립품의 연소성능시험을 실시하여 추력 400 파운드급의 로켓엔진의 설계성능을 확인하였다. 로켓엔진의 성능측정은 요소분사기의 미립화, 혼합성능의 측정을 위한 상온수류시험과 추진기관 조립체의 지상연소시험으로 실시하였으며, 연소성능은 산화제로 질산을 연료로는 아민계 혼합물로 구성된 접촉발화형 이원 액체추진제를 사용하여 가압방식에 의해 연소실에 분사하는 방법으로 수행하였다. 성능시험결과는 설계성능 및 이상성능과 비교함으로서 이들의 상관관계를 파악하였다.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2005.10a
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• pp.336-342
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• 2005

Stone column or granular compaction pile have been used in widely during the several decades as a technique to reinforce soft cohesive soils and increase bearing capacity, accelerate consolidation settlement of the foundation soil. The bearing capacity of the granular compaction pile is governed mainly by the lateral confining pressure mobilized in the native soft soil to restrain bulging collapse of the granular pile. Therefore, the technique becomes unfeasible in soft, compressible clayey soils that do not provide sufficient lateral confinement. This paper presents the main results of numerical study of granular compaction pile which is partly mixed with lean concrete. 3D finite element analyses are performed with composite reinforced foundations by both granular compaction pile and partly mixed granular compaction pile with lean-mixed concrete.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.183.2-183.2
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• 2012

최근 인공위성의 대형화 및 중량화 추세는 종종 기존 설비 내에서의 위성체 조립 및 시험업무의 작업성과 능률성을 심각하게 저해하는 요소로 작용한다. 이에 상기 업무의 원활한 수행을 위해서는 최적화된 설계의 기계지상지원장비(Mechanical Ground Support Equipment, MGSE)의 개발 및 활용이 요구되어지며, 이는 전체 위성개발기간 동안 요구되는 모든 시험 구성, 외부 설비 및 장비와의 인터페이스, 작업자의 동선 및 접근성 등을 종합적으로 고려해야 하는 작업이다. 특히 고해상도 영상안테나와 같이 높은 수준의 정렬 조건이 부과되는 탑재체의 경우 이의 장착, 정렬 및 지상전개시험 등을 위해서는 탑재체 및 위성체의 특성을 고려한 전용 장비의 개발도 필수적이다. 본 논문에서는 한국항공우주연구원이 최근 개발한 중대형급 지상관측 영상레이더 위성 개발 과제에 활용된 기계지상지원장비의 설계, 제작 및 운용 방법을 종합적으로 기술하였다.

• Aerospace Engineering and Technology
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• v.3 no.2
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• pp.98-103
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• 2004

This paper describes a system design of Launch Ground Complex for the Korea Space Launch Vehicle-I which will play so important roles of successful execution for Korea National Space Development Program. Launch Ground Complex has to supply safe work space, construction and equipments for assembling, check-out and launching of the space launch vehicle, and it consists of Mechanical, Electrical, Fluid Ground Support Equipment and Infrastructure. Mechanical Ground Support Equipment consists of Launch Pad, Mobile Assembly Tower, Umbilical Tower, Lightning Tower, Theodolite Building and Auxiliary.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.11
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• pp.95-105
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• 2005

The HAUSAT-2 nanosatellite which is scheduled to launch in 2008 is being developed by SSRL(Space System Research Lab.). The HAUSAT-2 STM(Structural-Thermal Model) was developed as the first system model to verify structural and thermal design margin. The qualification level vibration and thermal tests have been conducted on STM. This paper addresses the comparison of structural analysis and test results of HAUSAT-2 STM. It was shown that the natural frequency of HAUSAT-2 STM satisfies the stiffness requirements without structural damage in the random vibration test. The assembly and integration validity were also checked out through STM.

• Journal of the Korean Society of Propulsion Engineers
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• v.20 no.6
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• pp.91-100
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• 2016

Efficiency characteristics of centrifugal turbopumps for a liquid rocket engine were investigated. Predicting the performance of pumps for a turbopump assembly test, the variation on pump efficiency by working fluids was analyzed from pump component tests. Water and liquid nitrogen (LN2) were used for the component test, kerosene (Jet A-1) and liquid oxygen (LOX) were adapted for the turbopump assembly (TPU) test as working fluids. Overall performance of the pumps was investigated covering design/off-design operating points and the pump efficiency on the environment of real media (LOX/kerosene) could be modified from the pump component tests.

• Journal of the Korean Society of Propulsion Engineers
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• v.19 no.2
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• pp.65-72
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• 2015

Performance tests of a turbopump for the developing 7-tonf liquid rocket engine were conducted. The performance of turbopump components and their power matching were measured and examined firstly under the LN2 and water environment. In the real propellant(LOX and kerosene) environment tests, design and off-design performances of turbopump were fully verified. During the off-design tests, turbopump running time was set the same as engine operating time and pump inlet pressure were set lower than nominal operating value in order to investigate pump suction capability. It have been verified that subject turbopump satisfies required performance - flow rate, head, suction performance and operational time - in the operating regime of developing liquid rocket engine.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.5C
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• pp.211-220
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• 2012

Coarse granular materials such as gravel, rubble is used as major fill materials in earth structures of railway, road and dam. Therefore, it is essential to accurately evaluate properties of these materials for reasonable design and construction. In the precedent study, we built large triaxial testing system and verified system compliance with a focus on the dynamic properties. And we could secured the reliability of the system. In this study, the cyclic triaxial tests were performed in various experimental conditions on coarse granular material. Two series of parallel graded samples are prepared by mixing crushed rock. The influence of grain size, loading pattern, loading frequency, and fine contents were analyzed and discussed.