• Journal of computational fluids engineering
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• v.11 no.3 s.34
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• pp.8-13
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• 2006

The north panel of a geostationary satellite is used as one of the main radiators, on which communication equipment or bus equipment are installed. The thermal control of panel is designed by using embedded heat pipes and surface heat pipes (or external heat pipes) to spread out heat dissipated from equipment all over the radiator evenly and finally to reject the heat to the space through the radiator efficiently. This panel is also divided by several areas based on the operating temperature and dissipation of equipment in order to increase heat rejection capability of radiator. The thermal analysis is carried out for the hot case, Winter Solsitce EOL (End Of Life), in order to validate thermal design of the panel utilized 6 surface heat pipes and 8 embedded heat pipes. The sensitivity studies for the heat pipe failure case and no heat pipe case are performed and compared to its normal state. The heat transport capability of heat pipe is also obtained from these calculations.

• Journal of computational fluids engineering
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• v.10 no.3 s.30
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• pp.63-69
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• 2005

The COMS, the first meteorological geostationary satellite in Korea, is under development by KARI. The radiator size and the heater power for the thermal control of COMS are calculated using an analytic method. The total radiator area of $4.85\;m^2$ and the total heater power of 794.77 W are determined at a conceptual design of COMS. The commercial software, SINDA and TRASYS, are utilized in order to compare and verify the analytic results. The results of on-orbit numerical simulation of cold and hot cases show that the radiator size and heater power obtained from the analytic method are appropriate to maintain COMS equipments within required temperature ranges.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.2
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• pp.257-260
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• 2014

In this paper, a high gain waveguide array antenna combining horn antenna on slot radiator was designed. And the fabricated antenna showed enough gain, improved efficiency and broadband characteristics for receiving satellite signals, compare to conventional microstrip antenna which has dielectric loss and radiation loss on transmission line. For easy fabrication, the waveguide structure was composed by 3-stages of radiator, signal coupler and transmission line. By experiment, the array waveguide antenna of 4 by 16 showed 28.3[dBi] gain and 2:1 of VSWR. And by combining horn antenna structure, the gain was increased 1[dB]. The received signal from Koreasat 6 by measurement showed 16[dBc] of C/N on BS(Broadcasting Satellite)-band and 14[dBc] of C/N on CS(Communication Satellite)-band.

• Bulletin of the Korean Space Science Society
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• 2006.10a
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• pp.159-159
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• 2006

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.45 no.8
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• pp.678-685
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• 2017

The radiator of the data storage and handling units onboard the earth observation satellite is a groove-type radiator covered with a shield because of the periodic high heat dissipation and design characteristics of arrangement and mountability of the unit. The effect of the groove-type radiator and that of the shield versus plane radiator were verified through the thermal vacuum test. Through the test result, the temperatures of the radiator and the heat exchange due to the view factor were analyzed by using the analytical method. Conclusively the thermal performance of the shield dissipation plate was verified.

• Journal of Aerospace System Engineering
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• v.13 no.2
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• pp.66-72
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• 2019

The observation satellites which uses high heat-dissipating equipment such as synthetic aperture radar (SAR) satellites require a radiator to transmit heat from the equipment into outer space. However, during cold conditions it requires a heater to maintain the temperature of equipment within the allowable minimum limit when it is not in operation. In this study, we proposed a variable conductivity radiator that changes its thermal conductivity value through movement of the liquid metal between two reservoirs based on the temperature condition. This reduces the power consumption of the heater by limiting heat transfer path to the radiator in cold condition, while effectively transferring heat to the radiator during hot condition. The feasibility of the proposed radiator was validated through comparison of the thermal control performance with the conventional fixed conductivity radiator via a thermal analysis.

• Journal of computational fluids engineering
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• v.12 no.3
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• pp.62-68
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• 2007

A conceptual thermal design is performed for the optical payload system of a geostationary satellite. The optical payload considered in this paper is GOCI(Geostationary Ocean Color Imager) of COMS of Korea. The radiative thermal control system is employed in order to expect a small thermal gradient in the telescope structure of GOCl. Two design margins are applied to the dedicated radiator dimensioning, and three kinds of configuration to the heater power sizing. A Monte-Carlo ray tracing method and a network analysis method are utilized to calculate radiative couplings and thermal responses respectively. At the level of conceptual design, sizing thresholds are presented for the radiator and heater on the purpose of determining the mass and power budget of the spacecraft.

• Aerospace Engineering and Technology
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• v.10 no.2
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• pp.114-120
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• 2011

Thermal control of satellite is mainly based on passive ways, such as the radiator made of aluminum honeycomb core with aluminum skins and OSR (Optical Solar Reflector). Additionally, for the thermal control of high dissipation unit, the aluminum doubler and heat pipe are utilized. Recently, efforts to find advanced thermal materials have been carried out to enhance heat rejection capability without increasing satellite size, weight and cost. This paper handles the carbon composites have high thermal conductivity with light weigh and have been considered as future thermal control materials to replace aluminum based radiator and doubler. Thermal analysis of satellite panel using APG(Annealed Pyrolytic Graphite) and carbon-carbon composites were performed and temperature contours were compared with the conventional thermal control methods.

• Journal of the Korea Institute of Military Science and Technology
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• v.26 no.1
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• pp.54-63
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• 2023

In this paper, a VHF band conformal antenna for UAV mounting was developed. The proposed antenna was designed as an shape-adaptive structure by minimizing the antenna height to be advantageous in RCS reduction performance. As for the antenna radiator, the outer radiator was arranged around the inner radiator to apply the CRLH zeroth-order resonance structure. With this structure, the height of the antenna was minimized, and it was reduced by about 70 % compared to the existing blade antenna. In addition, for impedance matching, the intermediate frequency bandwidth of the VHF band was improved through the sleeve pin of the inner radiator, and the low frequency bandwidth of the VHF band was improved by applying an EMI shielding gasket to the shorting pin of the outer radiator. The proposed antenna was manufactured and measured to verify the performance of the device and the performance after UAV mounting. As a result, the standard was satisfied for the operating frequency.

• Journal of computational fluids engineering
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• v.15 no.3
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• pp.66-72
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• 2010

The north and south panel of a geostationary satellite are used for radiator panels to reject internal heat and utilize several heat pipe networks to control the temperatures of units and the main structures of satellite within proper ranges. The design of these panels is very important and essential at the conceptual design and preliminary satellite design stage, so several thousands of nodes or more are utilized in order to perform detailed thermal analysis of panel. Generating a large number of panel nodes takes time and is tedious work because the nodes can be easily changed and updated by locations of units and heat pipes. Also the detailed panel model can not be integrated into spacecraft thermal model due to its node size and limitation of commercial satellite thermal analysis program. Thus development of a program was required to generate a detailed panel model, to perform thermal analysis and to make a reduced panel model for the integration to the satellite thermal model. This paper describes the development and the verification of the panel thermal analysis program with its main modules and functions.