• Aerospace Engineering and Technology
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• v.4 no.1
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• pp.57-65
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• 2005

Due to the future of a large size satellite like Geo-stationary orbit satellite, KARI has progressed the construction of Large Thermal Vacuum Chamber(LTVC) with Φ8mXL10m, which simulates the orbit environment at space. The space environment can be characterized as very harsh conditions. Once the spacecraft is launched and enters its orbit, the satellite is exposed to this space environment. The continuous exposure to such space environment could cause malfunction of major parts of the spacecraft, which could lead to the failure of the entire mission. Due to the fact that space environment is completely different from that of the ground, the satellite that functioned normally on the ground could show some unexpected malfunction in space environment. For this reason, the performance of the spacecraft must be confirmed under the simulated conditions of the space environment. This document includes LTVC control logic, Interlock by which the LTVC can be controlled more safely and efficiently.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.4
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• pp.311-317
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• 2015

This paper describes how to apply one-dimensional simulation to predict unsteady state characteristics of the cold-gas pintle thruster. Mass flow rate, chamber pressure, and nozzle exit pressure are key parameters for thrust control. Chamber pressure rose and fell monotonously with the pintle stroke variation, while thrust variation was different from chamber pressure variation. During the forward pintle stroke operation, the thrust value tended to decrease initially and returned to increase when pintle speed and chamber free volume exceed some specified value. Even though one-dimensional simulation has the limitations to predict unsteady state characteristics, it is still useful for initial performance assessment of various thrusters which adopt an altitude compensation nozzle such as a dual-bell nozzle, prior to experiment or numerical analysis.

• Aerospace Engineering and Technology
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• v.2 no.2
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• pp.45-49
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• 2003

A Bake-Out test for STSAT-1 FM(Flight Model) was performed in a Bake-Out Chamber at SITC(Satellite Integration & Test Center) in KARI(Korea Aerospace Research Institute). The purpose of this test is to measure and analyze the outgassing rate to affect the optical equipment(FIMS) and to eliminate contaminants through the high temperature bake-out. This Bake-Out test is composed of three parts which are honeycomb panels & harnesses(Batch 1), an assembled satellite(Batch 2), and a disassembled satellite(Batch 3). For each test, quantitative and qualitative measurements and analysis were performed using TQCM(Thermoelectric Quartz Crystal Microbalance) and RGA(Residual Gas Analyzer.)

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.114-114
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• 2010

산불에 노출되는 경우 열충격으로 작용하는 패턴과 특성을 검토하여 가속열화시험에 반영하는 것이 필요하다. 본 연구에서는 산불환경을 모의하여 복합열화시험을 실시하기위해 복합가속열화 챔버를 구축하였다. 온도는 주로 $200^{\circ}C$에서 최대 $1000^{\circ}C$까지 변화를 주면서 예비시험과 본시험 실하였다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.05a
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• pp.567-568
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• 2021

In this paper, we design, fabricate, and test the performance of a cabin filter with LED modules of composite wavelengths containing UV-A and UV-C. Germs and air farms of the manufactured cabin filter confirmed sterilization capability in the sterilization test, and special chambers were manufactured to verify organic material decomposition capability in the organic compound decomposition test. Using colkates as photocatalytic was proved to be superior to using metal mash. The sterilization and air purification capabilities of the cabin filter produced throughout this study were verified through a similar environmental test.

• Journal of Aerospace System Engineering
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• v.13 no.4
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• pp.18-25
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• 2019

Studies on the fabrication of UAV by using 3D printer have been actively carried out. However, research on structural load characteristics in low temperature environment is insufficient. In this study, a composite sandwich structure with ordinary orbs structure was proposed, and the load characteristics for temperature condition changes were analyzed. The ordinary orbs and honeycomb structures were fabricated by using a FDM type 3D printer. The bending load test was carried out at room temperature and low temperature condition. The low temperature condition was classified into four cases. Bending load tests were performed in a low temperature chamber to maintain the required temperature conditions. As a result of the test, it was confirmed that the proposed ordinary orbs structure had better load characteristics at low temperatures than the existing honeycomb structure.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.6
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• pp.605-611
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• 2010

The geostationary satellite COMS is going to be launched in 2010, and, in the series of test, there are some high-pressure tests concerning the vessel tank filled with helium gas of hundreds atmospheric pressure. In this paper, authors evaluates risk associated with accidental rupture of the test system. Two possible scenarios are considered: 1) the 310-bar helium tank ruptures at the center of the acoustic chamber, and 2) the 116-bar reduced-pressure helium tank ruptures in the test room shielded by bullet-proof glasses. Using the theory of blast wave propagation and computational simulation, the dynamics of wave reflected in a confined space is investigated for highly complex unsteady flow physics.

• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.566-568
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• 2005

STACIR/AW은 최근 사용이 증가되고 있는 증용량전선으로 기존 송전선에 비해 많은 전류를 송전하면서도 이도특성이 우수한 장점을 가지고 있다. 이 논문에서는 STACIR/AW 전선의 온도 및 대전류특성에 대한 실증시험을 위하여 구축된 송전선로용 3[kA]급 대전류 발생 장치를 이용해 345kV 송전선로의 표준경간인 350m 시험선로에 $480\;mm^2$ 및 $410\;mm^2$ 전선을 가선하여 전류 특성 시험을 수행하였다. 본 논문에서는 최대 허용전류에 대한 단계별 이도특성을 외기 조건과 전선의 장력 변화를 고려하여 고찰하여 국내 주요 전선사의 증용량전선에 대한 신뢰성을 검증하고, 또한 계절별 특성시험 및 환경시험 챔버를 이용한 참고시험과 기본적 동적해석을 통하여 외기 조건에 전선의 최대허용전류를 검토하였다. 또한 실선로에 적용된 $480\;mm^2$ 및 $410\;mm^2$ 의 증용량 전선에 최대 부하율을 파악하고 동일 조건에 부하전류를 인가한 실증시험을 통하여 전선의 이도증가율을 분석하여 상용선로의 운전조건을 검토하였다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.1026-1030
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• 2017

In this study, we propose an supersonic diffuser that is one of test facilities for hypersonic propulsion engine, and conduct numerical analyses and cold flow test using each diffuser as the corresponding variable. Specifically, inner flow characteristics are computed based on mach number and pressure by the numerical analyses. Also, we test through cold flow test the pressure in the vacuum chamber and the inner pressure that is formed by the wall pressure. Finally, we compare the results from cold flow test and the numerical analyses, and report a preliminary result that might be useful to construct a better test facility of hypersonic propulsion engine in the future.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.131-131
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• 2012

압전재료는 그 특성상 항공우주분야에서 활용범위가 넓어지고 있는데, 특히 진동제어 분야에 널리 이용되고 있다. 최근에는 위성카메라의 영상 품질개선을 위한 구동기(actuator) 연구도 진행 중이다. 그러나 위성체가 작동하는 우주환경인 고진공상태에서는 각 부품에서 발생할 수 있는 outgassing으로 인해 위성체가 오염되어 위성임무 실패를 초래할 수도 있다. 따라서 지상에서 위성체 부품에 대해 고온($60^{\circ}C$)과 고진공(5.0 E-03 Pa 이하)의 상태를 모사하여 오염물질을 제거함으로써 outgassing 발생을 막고, 오염근원을 검출할 수 있는 bacuum bake-out 시험이 필요수적이다. 압전체의 위성부품 활용성 연구를 위하여 bake-out 챔버를 이용하여 오염측정에 관한 연구를 수행하였다. Vacuum bake-out 시험시에는 TQCM을 사용하여 발생하는 오염물질의 방출률을 측정한다. 아울러, 압전체에 대한 시험 전후의 압전특성을 비교 분석하여 진공 및 온도 환경하에서의 특성 변화를 관찰하였다.