• 한국전산유체공학회:학술대회논문집
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• 2007.10a
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• pp.227-231
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• 2007

COMS (Communication, Ocean and Meteorological Satellite) is a geostationary satellite and has been developing by KARI for communication and 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.

• Aerospace Engineering and Technology
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• v.10 no.2
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• pp.65-73
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• 2011

After launch, in order to inject the geostationary satellite into its operational orbit, the perigee altitude are forced to be raised to geostationary altitude by firing onboard LAE(Liquid Apogee Engine) at apogee of the transfer orbit. In this process, the LAE burn is divided into three or four separated burns in order to control the orbit very precisely by giving feedback the determined orbit informations and to inject the satellite in predefined longitude. This paper proposes an algorithm to determine LAE firing time slots and ${\Delta}V$ vectors under assumption of impulsive LAE burning, and additionally, a method to compensate errors induced by continuous burning. And computer simulations have been performed to validate proposed algorithms.

• Journal of the Korean Operations Research and Management Science Society
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• v.30 no.1
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• pp.177-185
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• 2005

We consider the optimization problem of the geostationary satellite orbital positions. which is very fundamental and important in setting up the new satellite launching plan. We convert the problem into a discrete optimization problem. However, the converted problem is too complex to find an optimal solution. Therefore, we develope the solution procedures using simulated annealing technique. The results of applying our method to some examples are reported.

• ETRI Journal
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• v.30 no.6
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• pp.774-782
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• 2008

An operational orbit determination (OD) and prediction system for the geostationary Communication, Ocean, and Meteorological Satellite (COMS) mission requires accurate satellite positioning knowledge to accomplish image navigation registration on the ground. Ranging and tracking data from a single ground station is used for COMS OD in normal operation. However, the orbital longitude of the COMS is so close to that of satellite tracking sites that geometric singularity affects observability. A method to solve the azimuth bias of a single station in singularity is to periodically apply an estimated azimuth bias using the ranging and tracking data of two stations. Velocity increments of a wheel off-loading maneuver which is performed twice a day are fixed by planned values without considering maneuver efficiency during OD. Using only single-station data with the correction of the azimuth bias, OD can achieve three-sigma position accuracy on the order of 1.5 km root-sum-square.

• 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 Satellite, Information and Communications
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• v.8 no.2
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• pp.80-87
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• 2013

Communication Ocean Meteorological Satellite (COMS) has the hybrid mission of meteorological observation, ocean monitoring, and telecommunication service. The COMS is located at $128.2{\circ}$ east longitude on the geostationary orbit and currently under normal operation service since April 2011. In order to perform the three missions, the COMS has 3 separate payloads, the meteorological imager (MI), the Geostationary Ocean Color Imager (GOCI), and the Ka-band communication payload. The satellite controls for the three mission operations and the satellite maintenance are done by the real-time operation which is the activity to communicate directly with the satellite through command and telemetry. In this paper the real-time operation for COMS is discussed in terms of the ground station configuration and the characteristics of daily, weekly, monthly, seasonal, and yearly operation activities. The successful real-time operation is also confirmed with the one year operation results for 2011 which includes both the latter part of the In-Orbit-Test (IOT) and the first year normal operation of the COMS.

• 한국전산유체공학회:학술대회논문집
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• 2009.04a
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• pp.135-141
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• 2009

A preliminary thermal analysis 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 and conductive thermal models are employed in order to predict thermal responses of the GOCI on the geostationary orbit. According to the results of this analysis are as follows: 1) the GOCI instrument thermal control is satisfactory to provide the temperatures for the GOCI performances, 2) the thermal control is defined and interfaces are validated, and 3) the entrance baffle temperature is found slightly out its specification, therefore further detailed analyses should be continued on this element.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2005.11a
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• pp.426-430
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• 2005

The COMS(Communication, Ocean and Meteorological Satellite) is the first developed three-axis stabilization multi-function satellite on geostationary earth orbit(GEO) in korea, presently scheduled to be launched in 2008. The COMS propulsion system provides the thrust and torque required for the insertion into GEO, attitude and orbit control/adjustment of spacecraft. In this paper, system design of propulsion system, basic functions and design requirement of components are described.

• Journal of Astronomy and Space Sciences
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• v.41 no.1
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• pp.17-23
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• 2024

The safety of electronic components used in aerospace systems against cosmic rays is one of the most important requirements in their design and construction (especially satellites). In this work, by calculating the dose caused by proton beams in geostationary Earth orbit (GEO) orbit using the MCNPX Monte Carlo code and the MULLASSIS code, the effect of different structures in the protection of cosmic rays has been evaluated. A multi-layer radiation shield composed of aluminum, water and polyethylene was designed and its performance was compared with shielding made of aluminum alone. The results show that the absorbed dose by the simulated protective layers has increased by 35.3% and 44.1% for two-layer (aluminum, polyethylene) and three-layer (aluminum, water, polyethylene) protection respectively, and it is effective in the protection of electronic components. In addition to that, by replacing the multi-layer shield instead of the conventional aluminum shield, the mass reduction percentage will be 38.88 and 39.69, respectively, for the two-layer and three-layer shield compared to the aluminum shield.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.42 no.8
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• pp.661-673
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• 2014

In this paper, a precise orbit determination process was carried out based on KARISMA(KARI Collision Risk Management System) developed by KARI(Korea Aerospace Research Institute), in which optical tracking data of a geostationary satellite was used. The real optical tracking data provided by ESA(European Space Agency) for the ARTEMIS geostationary satellite was used. And orbit determination error was approximately 420 m compared to that of the ESA's orbit determination result from the same optical tracking data. In addition, orbit prediction was conducted based on the orbit determination result with optical tracking data for 4 days, and the position error for the orbit prediction during 3 days was approximately 500~600 m compared to that of ESA's result. These results imply that the performance of the KARISMA's orbit determination function is suitable to apply to the collision risk assessment for the space debris.