• Journal of the Korean Society of Propulsion Engineers
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• v.21 no.1
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• pp.44-50
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• 2017

Vehicle Holding Device(VHD) has a role that holding the launch vehicle on its launch pad until the engine therust reaches a steady condition. The analytical study of shape parameters and dynamic characteristics of hydraulic cylinders is carried out. The contraction of cylinder is considered as the major factor of releasing mechanism. Through the analysis, the decreasing of cylinder slit size and increasing initial charging pressure increase the contraction force. Through the transient analysis, cylinder load, displacement and inner pressure distribution are confirmed. The cylinder contraction force is converged to the cylinder external force when the cylinder starts to move. Also, the pressure distribution in the hydraulic cylinder is constant.

• Journal of Satellite, Information and Communications
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• v.7 no.1
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• pp.86-91
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• 2012

This paper described validation results of COMS Ka band antennas beam coverages which were developed by ETRI. After satellite launch, In Orbit Test(IOT) activities are stat to check spacecraft and payloads are still in healthy condition after launch. During IOT phase, ETRI measured radiation patterns of COMS Ka band antennas and compare with ground test(CATR) results. The antenna patterns similarity between IOT results and CATR results show that COMS Ka band antenna withstand launch vibration and in the good healthy condition. After IOT, ETRI performed field test for beam coverage measurements with vehicle to check if Ka band beam coverage are formed well as designed. For the beam coverage measurement, 17 points were selected over the Korean peninsula. The field measurement data were very similar with CATR data and this confirms that beam coverage are formed well over the Korean peninsula as expected.

• Journal of the Korea Institute of Military Science and Technology
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• v.15 no.1
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• pp.86-92
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• 2012

When missile is launched, a launcher needs to be leveled with accuracy to avoid the systems's instability. In general, a launcher is leveled by adjusting the stroke of leveling jacks; however, it is still challenge to control the leveling jacks fast and accurately. This paper thus proposed an innovative algorithm for compensating ground inclination of a missile launcher to expand operational field of a missile launcher. Using two inclinometers attached on a launcher, a base jack for leveling is selected and the mixed gradient where launcher stands on can be estimated. Due to the limited stroke, the launcher can compensate its ground inclination within maximum stroke margin. Then, the ground inclination of a launcher can be compensated by calculated angle using weighting factors. The effectiveness of proposed algorithm is proved with a prototype missile launcher.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2012.04a
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• pp.381-384
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• 2012

2010년 06월 09일 소형위성발사체의 비행시험을 준비 하던 중 화재확산방지 장치가 오작동 하는 사고가 발생 하였다. 이 사고로 소화수 100톤과 소화약제 3톤이 분출 되었고, 소형위성발사체의 비행시험은 하루 지연 되었다. 오작동의 직접적 원인은 제어기 부분의 오작동으로 판단되어, 관련 제어기 및 통신라인 부품들을 모두 교체하고, 발사통제동과 발사대간의 통신선로도 이중화 하였다. 아울러 제어기의 입출력 신호를 실시간으로 기록하기 위한 장비도 추가로 설치하여 전반적인 설비의 신뢰도를 높였다.

• Bulletin of the Korean Space Science Society
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• 2009.10a
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• pp.25.1-25.1
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• 2009

적외선 우주배경복사 관측실험 (Cosmic Infrared Background ExpeRiment, CIBER) II는 2009년 2월 25일 화이트샌드 미사일 기지에서 NASA 사운딩 로켓에 탑재, 발사된 CIBER I의 후속 프로젝트이다. 독립적인 Imager 2 대와 Spectrometer 2 대로 구성된 CIBER I과 달리 CIBER II는 하나의 주경과 부경으로 구성된 광학계를 4 대의 Imager가 beam splitter를 이용하여 관측하게 구성되어 있다. CIBER II는 NASA에서 공식적으로 승인되었으며, 한국천문연구원과 한국기초과학지원연구원이 미국 NASA/JPL, Caltech 및 일본 ISAS와 국제 공동으로 개발할 계획이다.

• Aerospace Engineering and Technology
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• v.10 no.2
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• pp.133-145
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• 2011

This paper is about the results in Qualification Management activity performed between the Autonomous Test(AT) season(August. 2008) of Launch Complex and the 2nd flight test season(June. 10, 2010) of KSLV-I. All cryogenic fluids(LOX, $LN_2$) and compressed gases(Air, $GN_2$, GHe) were qualified by qualification management activity during AT(Autonmous Test), QT(Qualification Test) season for LP(Launch Pad) and LVAB(Launch Vehicle Assembly Building) and FT(Flight Test) season of KLSV-I. As the results, total 428 times of check analysis and 111 times of full analysis were performed.

• The Journal of the Acoustical Society of Korea
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• v.33 no.1
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• pp.10-20
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• 2014

To study the water-entry impact noise, on-board experiment using a small launcher firing various objects was performed in the Yellow Sea. As the launcher fires a cylindrical object from the ship vertically, generated noise is measured with a hydrophone on the starboard of Chung-hae, Marine surveyor. Three types of cylindrical objects, which have noses of flat-faced, conical, and hemisphere, were used during the experiment. The measured noise exhibits a time-dependency which can be divided into three phases: (1) initial impact phase, (2) open cavity flow phase, (3) cavity collapse and bubble oscillation phase. In most cases, the waveform of bubble oscillation phase is dominant rather than that of initial impact phase. Pinch-off time, where a cavity begins to collapse, occurs at 0.18 ~ 0.2 second and the average lasting time of bubble was 0.9 ~ 1.3 second. The energy of water-entry impact noise is focused in the frequency region lower than 100 Hz, and the generated noise is influenced by the nose shapes, object mass, and launching velocity. As a result, energy spectral density on the bubble frequency is higher in the order of flat-faced, conical, hemisphere nose, and the increase of initial energy raises the energy spectral density on the bubble frequency in the cylinder body of same shape. Finally, we compare the measurements with the simulated signals and spectrum based on the bubble explosion physics, and obtain satisfactory agreements between them.

• Aerospace Industry
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• s.90
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• pp.57-59
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• 2006

보잉,호주 737 AEW&C 주요 시험 완료/미 공군, 무인폭격기 개발에 20억 달러 투자/독일·프랑스, 대형 수송헬기 개발/미, 국방부 작년도 10대 방산계약업체 발 표/에어버스 밀리터리,A400M 수송기 형식증명 신청/나사,CEV 및 달착륙 임무계획 구체화/일본, 첨단 지상관측위성 발사/유럽우주기구,4대의 갈릴레오 항법위 성 제적 계약/X-51A 극초음속기 스크램제트 시험 계획/인도,유인우주임무 검토/캐나다 봄바디어,수호이의 RRJ사업참여 고려/프랑스 닷소사,중국에 팰컨 900DX 비즈제트 판매/중국,150인승 여객기 개발 준비/보잉 및 에어버스 기록적인 수주 실적

• Defense and Technology
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• no.9 s.127
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• pp.60-67
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• 1989

웨스팅하우스는 공중화력통제 레이다, 전자전, 전자광학장치, 육.해.공레이다 감시체계, 선상지휘 및 통제 패키지들과 기뢰에 대한 방어수단인 수중 음파 탐지기와 어뢰를 포함한 대잠수함전 장비(ASW)들을 최초로 제작한 회사이다. 웨스팅하우스의 제품은 수중추진 및 발사체계로부터 위성 센서까지 망라한다. 또한 미국의 가장 중요기술상품인 "생산체계종합"의 선두주자이기도 하다. 세계10대 국제 군수제조 및 서비스업체로 꼽히고 있으며, 앞으로의 성장과 전망을 볼 때, 향후 매년 8.5 %이상의 매출 성장을 달성할 것이라 한다

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.11a
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• pp.347-352
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• 2009

Pneumatic system is widely applied to ground facility and launcher on-board system. The main requirements of pneumatic system is to meet pressure and flow requirements of gas consumers. For launcher related applications, different from other applications, very high flow is required which can leads to supply pressure drop against required setting pressure. The supply pressure decrease is closely related to regulator characteristics. In this paper, the characteristics of pneumatic regulator related to supply pressure decrease and the control methods for reducing the pressure offset are reviewed.