• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.2
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• pp.178-183
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• 2012

To simulate space thermal environment in thermal vacuum test, direct or in-direct heater has been applied on the radiator. Both of them, direct heater attached on the radiator and indirect heater with a distance from the radiator, simulate the heat fluxes from the Sun radiation, the Earth IR and Albedo. They also supply the heat fluxes to the radiator of spacecraft to achieve the target temperature according to thermal test conditions. In general, indirect heater is used when the heater is not allowed to attach on the radiator directly due to constraints of coating property or contamination. For in-direct heater design, it is needed to estimate the heat power to make the extreme test conditions and minimize the interference with heat exchange of radiator and shroud. In this study, optimized thermal design of in-direct heater is proposed and investigated by commercial S/W SINDA. The effective values of design factors are also derived.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.6
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• pp.645-652
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• 2016

The basic equation of body and mind that can be represented as body and mind based on love model of Romeo and Juliet is presented in this paper. In order verify validity for physical idea of unification for body and mind when the external force is applied in the basic equation. We display the time series and phase portrait for nonlinear behavior, and this paper confirms the point of difference between body-mind neutral monism and body-mind dualism.

• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.2
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• pp.253-260
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• 2015

Love which is one of the emotional of mankind, has been studied in sociology and psychology as a matter of grate concern. In this paper we represent romantic behaviors in the love equation of Romeo and Juliet as time series and phase portraits in the case of with and without time delay. And we also analyze their difference.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.11
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• pp.1297-1304
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• 2014

Love which is one of the emotional of mankind, has been studied in sociology and psychology as a matter of grate concern. In this paper We represent romantic behaviors in the love equation of Romeo and Juliet as time series and phase portraits. Also we analyze the behavior's relation by using time series and phase portraits when external force applied as the third person between Romeo and Juliet.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.44 no.4
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• pp.373-379
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• 2016

The thermal control device for the periodic working component combined solid-liquid phase change material (PCM) with heat pipes is designed and numerically studied. Due to high latent heat and retaining constant temperature during melting process the component peak temperature, not withstanding small radiator size, is reduced. The warm-up heater power consumption to keep the minimum allowed temperature is also cut down since the accumulated thermal energy is released through the solidification. The thermal buffer mass (TBM) made of Al can give the similar effect but the mass and power consumption of warm-up heater should increase compared to PCM. The amount of PCM can be optimized depending on the component heat dissipation and on/off duty time.

• Journal of Astronomy and Space Sciences
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• v.18 no.1
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• pp.81-93
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• 2001

Far ultraviolet IMaging Spectrograph (FIMS) should be designed to maintain its structural stability and to minimize optical performance degradation in launch and in operation enviroments. The structural and thermal analyzes of grating and grating mount system, which are directly related to FIMS optical performance, was performed using finite element method. The grating mount was made to keep the grating stress down, while keeping the natural frequency of the grating mount higher than 100 Hz. Transient and static thermal analyzes were also performed and the results shows that the thermal stress on the grating can be attenuated sufficiently. The optical performance variation due to temperature variation was with the allowed range.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.11
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• pp.1008-1015
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• 2015

Thermal vacuum test should be performed prior to launch to verify satellites' functionality in extremely cold/hot temperatures and vacuum conditions. A thermal vacuum chamber used to perform the thermal vacuum tests of a satellite system and its components. A cryogenic blower is a core component of the gaseous nitrogen (GN2) closed loop thermal control system for thermal vacuum chambers. A final goal of this research is development of cryogenic blower. Design requirements of a blower are 150 CFM flow rate, 0.5 bara pressure difference, hot and cold temperatures. This paper describes the performance analysis of impeller by 1D, CFD commercial software, the design of the thermal protection interface between the driving part and the fluid part. The performance of the cryogenic blower is confirmed by test at the standard air condition and is verified by on the thermal vacuum chamber at the real operating condition.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.50 no.1
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• pp.31-38
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• 2022

TR module using in satellite must consider discriminative electrical and mechanical requirements compare to the one using in ground and aircraft system since not only the environment level of vibration and shock during the launch stage but also the level of radiation, vacuum and thermal variation from orbit environment are more severe than atmosphere condition. This paper describes the environmental conditions of launch and the orbit and, suggests design method of TR module applying GaN to satisfy the unique environmental requirements of satellite systems by especially focusing on parts selection, derating design, RF budget design, manufacturing process design, and thermal design of TR module.

• 한국전산유체공학회:학술대회논문집
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• 2009.04a
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• pp.142-147
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• 2009

COMS (Communication, Ocean and Meteorological Satellite) is a geostationary satellite and has been developing by KARI for communication, ocean and meteorological observations. It will be tested under vacuum condition and very low temperature in order to verify thermal design of COMS. The test will be performed by using KARI large thermal vacuum chamber, which was developed by KARI, and the COMS will be the first flight satellite tested in this chamber. The purposes of thermal balance test are to correlate analytical model used for design evaluation and predicting temperatures, and to verify and adjust thermal control concept. KARI has plan to use heating plates to simulate space hot condition especially for radiator panels such as north and south panels. They will be controlled from 90K to 273K by circulating GN2 and LN2 alternatively according to the test phases, while the shroud of the vacuum chamber will be under constant temperature, 90K, during all thermal balance test. This paper presents thermal modelling including test chamber, heating plates and the satellite without solar array wing and Ka-band reflectors and discusses temperature prediction during thermal balance test.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2001.10a
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• pp.99-104
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• 2001

Thermally induced vibration response of solar array is investigated. The solar array model consists of composite thin walled beam and solar blanket, spreader bar. The composite thin walled beam incorporates a number of nonclassical effects of transverse shear, primary and secondary warping, rotary inertia and anisotropy of constituent materials. The solar blanket is a membrane subjected to uniform tension in the z direction. The spreader bar is a rigid member. A coupled thermal structure analysis that includes the effects of structural deformations on heating and temperature gradient is investigated. A stability criterion given in parameters for establishes the conditions for thermal flutter.