• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.9
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• pp.814-821
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• 2015

The STEP Cube Lab. classified as a pico-class satellite has been successfully developed as a flight model(FM) to be launched in 2015. Its mission objective is to perform the on-orbit verification of fundamental space core-technologies. In this study, a thermal design concept based on the passive method to achieve the mission objective is introduced. The effectiveness of the thermal design and performance of the satellite has been verified through the acceptance level thermal vacuum test. In addition, to improve the reliability of thermal mathematical model, correlation was performed using the results of thermal balance test. This paper describes a series of process for the thermal vacuum test on the STEP Cube Lab. FM.

• Bulletin of the Korean Space Science Society
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• 2004.10b
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• pp.368-371
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• 2004

ETRI has developed the EQM (Engineering Qualification model) payload system for the communications and broadcasting satellite (CBS) with Korean local companies. This paper describes a series of environmental tests such as vibration, thermal/thermal vacuum, and EMC tests. All the development processes including the design, implementation, integration and workmanship were verified and evaluated by these tests. The results of the functional tests and the compliance to the requirements are also presented. The technologies and heritage obtained from this development will be applied to the development of the payload system for the Korean communication satellite in the near future.

• Journal of computational fluids engineering
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• v.13 no.2
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• pp.48-54
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• 2008

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 launched by ARIANE 5. Ka-band components are installed on South panel, where single solar array wing is mounted. Radiators, embedded heat pipes, external heat pipe, insulation blankets and heaters are utilized for the thermal control of the satellite. The Ka-band payload section is divided several areas based on unit operating temperature in order to optimize radiator area and maximize heat rejection capability. Other equipment for sensors and bus are installed on North panel. The ocean and meteorological sensors are installed on optical benches on the top floor to decouple thermally from the satellite. During the transfer orbit operation, satellite will be under severe thermal environments due to low dissipation of components, satellite attitudes and LAE(Liquid Apogee Engine) firing. This paper presents temperature and heater power prediction and validation of thermal control design during transfer orbit operation.

• 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.

• Journal of computational fluids engineering
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• v.20 no.4
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• pp.63-69
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• 2015

The thermal balance test in vacuum chamber for satellite structures is an essential step in the process of satellite development. However, it is technically and economically difficult to fully replicate the space environment by using the vacuum chamber. To overcome these limitations, the thermal analysis through a computer simulation technique has been conducted. The CFRP composite material has attracted attention as satellite structures since it has advantages of excellent mechanical properties and light weight. However, the nonuniform nature of the thermal conductivity of the CFRP structure should be noted at the step of thermal analysis of the satellite. Two different approaches are studied for the thermal analyses; a detailed numerical modeling and a simplified model expressed by an effective thermal conductivity. In this paper, the effective thermal conductivities of the CFRP composite structures are extracted from the detailed numerical results to provide a practical thermal design data for the satellite fabricated with the CFRP composite structure. Calculation results of the surface temperature and the thermal conductivities along x, y, z directions show fairly good agreements between the detailed modeling and the simplified model for all the cases studied here.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.10
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• pp.875-887
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• 2015

The optimal layout design is used in the development of various areas of industry. In the field of space systems, components must be placed properly in the limited space of spacecraft by considering mechanical, thermal and electrical interfaces. When applying optimal layout design, a proper, even ideal placement of components is possible in the limited space of a satellite platform. Through the optimal placement design, the minimized moment of inertia enhances efficient attitude control, rapid maneuver and mission performance of the satellite. This paper proposes 3D optimal layout design that minimizes the spacecraft's moment of inertia and effect of thermal dissipation between inner components as well as interference between inner components based on a cubic-structure satellite platform. This study proposes the new genetic algorithm for 3D optimal layout design of the satellite platform.

• Proceedings of the KSRS Conference
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• 2004.10a
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• pp.479-482
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• 2004

Laminate Design of a composite tube for a space telescope(Fig. 1) under hygrothermal load is studied. Carpet plots for laminate effective engineering constants are generated and used for selecting the best tube lay-ups satisfying the optomechanical requirements for a space telescope being dimensional1y stable under orbital thermal loading. Despace of the tubes constructed with the selected lay-ups are calculated with a Zig-Zag Triangular Element which accurately represents through thickness stress variations for laminated structures. The effects of moisture absorption when exposed to humidity environment and moisture desorption through outgassing on the dimensional stability are also investigated.

• Journal of Aerospace System Engineering
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• v.14 no.1
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• pp.36-43
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• 2020

The start of satellite thermal design was to predict the worst operating environment through analysis of the thermal environment of the operation orbit. Because the satellites have different types of operating trajectories for their mission, the exposed thermal environment also varies. Thus, it is necessary to analyze in consideration of the orbital conditions, and a design was performed to guarantee thermal stability for the worst case defined through the analysis. The orbital thermal environmental analysis required an understanding of the basic orbit mechanics and the heat exchange relationship between the space environment and satellite. The purpose of this paper was to provide an understanding of the orbital thermal environment analysis by providing basic data on the space thermal environment in the earth-orbit and describing thermal relations that calculate the amount of space heat inflow into satellites. Additionally, an example of a virtual satellite shows the overall process of analyzing the orbital thermal environment during a mission lifetime.

• Composites Research
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• v.28 no.4
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• pp.162-167
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• 2015

Composite sandwich structures are widely employed in various applications, due to their high specific stiffness and specific bending strength compared to solid panels. Lately, for that reason, the advanced composite sandwich structures are employed in satellite structures: materials should be as light as possible with the highest attainable performance. This study is majorly focused on inserts employed to the composite sandwich satellite structures. A new hybrid insert design was developed in precedent study to reduce the mass of the sandwich structure since the mass of the satellite structure is related to high launching cost [1]. In this study, the thermal characteristics and behavior of the precedently developed hybrid insert with carbon composite reinforcing web and the conventional partial insert were numerically investigated.

• Aerospace Engineering and Technology
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• v.10 no.1
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• pp.136-140
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• 2011

In this study, thermal model for backplane of GPS antenna in Low Earth Orbit Satellite is updated and orbit thermal analysis is performed. The analysis is focused on the safehold mode of satellite. During the safehold mode, the solar panel is constantly looking to the Sun, and there is not a mission maneuvering. Therefore, antenna backplane receives the maximum heat influx considering the End-Of-Life condition. To maintain the temperature of antenna within allowable limits, radiating tape is applied and its area is determined. Besides, to verify the lowest temperature of the antenna, cold case with Begin-Of-Life analysis is also performed.