• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.04a
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• pp.283-288
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• 2011

The spherical flange was designed to apply to a cryogenic high pressure pipe of the Liquid Rocket Engine. It is designed that the spherical flange is able to be assembled and kept airtight upto $2.5^{\circ}$ of the axial misalignment between the combined components. It increases the degree of freedom of the engine assembly. The spherical flange is composed of a ball and socket joint, a metal seal and spherical type bolts, washers. The prototype was verified by leak test at the room temperature and the cryogenic temperature. Additionally the strength test and the destructive test were performed at the room temperature.

• Journal of the Korean Society of Propulsion Engineers
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• v.15 no.3
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• pp.64-69
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• 2011

The spherical flange was designed to apply to a cryogenic high pressure pipe of a liquid rocket engine. It is designed that the spherical flange is able to be assembled and kept airtight up to $2.5^{\circ}$ of the axial misalignment between the combined components. It increases the degree of freedom of the engine assembly. The spherical flange is composed of a ball and socket joint, a metal seal, spherical type bolts and washers. The prototype was verified by leak test at the room temperature and the cryogenic temperature. Additionally the strength test and the destructive test were performed at the room temperature.

• Aerospace Engineering and Technology
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• v.3 no.1
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• pp.27-34
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• 2004

Tail-wing, gondola and thrust motor mount(EMS) were built by carbon/glass fiber composites. Structural strength & stiffness was verified by specimen tests. Static strength tests for each structural components were conducted separately. Boundary conditions are specially designed for each components to simulate exact joint conditions. Tests shows no detriment deformation at 100% DLL and no failure at 150% DLL.

• Journal of Aerospace System Engineering
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• v.16 no.4
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• pp.53-59
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• 2022

Static seals are used to seal high temperature gas and cryogenic fluid under high pressure, at interfaces between liquid rocket engine components such as combustion chamber, turbopump, gas generator, valves, etc. As thermal expansion and contraction at assembly interfaces cause undesirable leakage under cryogenic and high temperature environments, static seals applied for sealing of joint interfaces without relative motion should be designed properly. The additional function of rotation at the sealing face is also required for static seals, when the spherical flange is used for improvement of assembly at misalignment interfaces. In this study, structural analysis and leak tightness test of simulating test rig for several important interfaces are performed, to verify structural integrity of static seals.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.9
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• pp.103-113
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• 2004

The satellite is exposed to the severe vibration environments such as random vibration environments such as random vibration, acceleration, shock, and acoustics during launch ascent and transportation. It is also faced with various space environments such as thermal vacuum, radiation and microgravity during the mission life. The satellite should be designed, manufactured, assembled and tested to be able to endure in these harsh environments. This paper addresses the results of the structural and thermal design and analyses for the HAUSAT-1 picosatellite which is scheduled to launch in the first quarter of 2005 by Russian launch vehicle "Dnepr". The qualification vibration and thermal vacuum tests have been conducted and passed at the satellite level to ensure that the HAUSAT-1 mechanical system was designed to be stable with enough margin.

• Aerospace Engineering and Technology
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• v.7 no.1
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• pp.161-169
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• 2008

This paper introduces test configuration and operation method for the GPS receiver system under electromagnetic test of KSLV-I upper-stage as a system qualification level and describes performance analysis of the test results. The GPS receiver system has clearly passed the electromagnetic test specifications of component level which is based on MIL-STD-461E through several design changes. Under electromagnetic test as a system qualification level, the GPS receiver system normally operates in spite of electromagnetic interferences with other systems. Performance of the GPS receiver system is also, not degraded on the condition of electromagnetic field incidence and electrostatic discharge. The KSLV-I GPS receiver system, as a result, is verified on the electromagnetic condition of the KSLV-I upper-stage.

• Aerospace Engineering and Technology
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• v.6 no.2
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• pp.40-44
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• 2007

Based on the optical design type, the large aperture payload has not only a different characteristic of design, assembly and alignment but also its own merits and demerits. The analysis of characteristic has been performed according to the optical design type and based on this result, our camera is 4 reflective mirror system based on the Korsch type. Each mirror assembly is to be verified in the mirror manufacturer and the Optical Module(OM) will be assembled, aligned and tested by KARI. The final performance of camera depends on the several factors, especially, the optical performance of its OM In parallel with the optical design the conceptual design of OM assembly and alignment has been performed. In this paper, the analysis of characteristic has been performed according to the optical design type and the conceptual design of OM assembly and alignment was described with regard to optical performance.

• Proceedings of the KSRS Conference
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• 2008.03a
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• pp.53-58
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• 2008

인공위성을 통해 취득된 데이터들은 지상국의 수신처리시스템을 거쳐 표준영상으로 생산되며, 생산된 영상으로부터 사용자에게 의미 있고, 가치 있는 정보를 이끌어 내는 판독의 단계를 수행하게 된다. 본 연구에서는 원격탐사의 전반적인 이해를 돕기 위한 교육적 모델로서 캔샛 프로그램을 도입하였다. 캔샛 프로그램은 스탠포드대 로버트 트윙 교수의 제안으로 학생들에게 한 학기의 짧은 시간에 실제 인공위성의 설계, 해석, 제작, 조립, 시험, 발사, 운용 등 전반적인 시스템의 이해를 도모하기 위한 1Kg 이하의 캔 크기의 초소형 위성을 개발하는 교육 프로그램이다. 본 연구는 한국과학영재학교 R&E 프로그램의 지원으로 시작하였으며, 실제 초소형 위성 캔샛('KSAsat'으로 명명)을 직접 설계, 제작, 조립하고 최종적으로 발사 운용 시험을 수행하였다. 주 탑재체로 일반 상용 디지털 카메라를 장착하였으며, GPS, 광센서, 3 축 가속도계, 온도센서, 압력센서를 탑재하였다. 비행시험을 통해 성공적으로 영상을 취득하고, 각종 센서로부터의 데이터를 지상국으로 전송 받았다. 지상국을 통해 처리 되어진 데이터로부터 의미 있는 정보를 추출하는 판단의 단계를 거쳐 원격탐사의 전반적인 교육을 성공적으로 수행할 수 있었다. 본 논문에서 캔샛 프로그램이 원격탐사 교육에도 충분히 활용될 수 있음을 보였다.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.225-225
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• 2012

국내에서 크라이오펌프를 생산한 지 여러해가 지나 냉동기 및 활성탄 어레이를 비롯한 대부분의 핵심 부품들을 가공하고 펌프를 조립하는 것을 자체적으로 해결하고 있지만 지금까지 펌프의 구조설계는 외국 제휴 회사에서 전수받은 것을 큰 수정없이 고수해 온 것이 현실이다. 따라서 펌프의 성능에 관한 별도의 시험과정 없이도 제공받은 성능값을 그대로 제시하는 것으로 충분했다. GVT(주)는 국내의 선도적인 크라이오펌프 전문생산 업체로서 독자적인 냉동기와 어레이 및 배플 설계에 기초한 신규 모델들을 정립하고 펌프를 생산하기 시작하였으며 다양한 크기의 표준용기를 마련하여 전 모델에 대해서 엄격한 시험검사를 시행하고 있다. 본 발표에서는 특별히 구경 200 mm UHV형 크라이오 펌프의 배기속도, 배기용량, cross-over 등 주요 배기성능 지표들을 측정한 결과 및 몬테카를로 계산을 통한 예측치와 비교한 결과를 소개한다.

• Journal of Aerospace System Engineering
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• v.11 no.4
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• pp.48-53
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• 2017

Liquid rocket engines (LREs) are very complex systems that include combustion chambers, turbopumps, gas generators, ducts and tubes, valves and etc. Most components of the LREs require higher than or equal to level 6 IT (ISO Tolerance). The components along with pipe line and/or tubing must dispose not to interfere each other. In addition, effectiveness of maintenance and service after assembling should be considered when the allocation of the components are determined. Especially at the stage of the development, tolerance accumulations or unpredictable errors may result in misalignment and/or mismatches at interfaces of the parts. Namely, it is the engine assembling process that many inherent risks are realized and crises or incidents occur. Therefore, a rapid reaction system should be prepared. In this research, 7 tonf class liquid rocket assembling process was studied and actual building steps were introduced.