• Proceedings of the KSRS Conference
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• 2005.10a
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• pp.104-107
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• 2005

COMS(Communication, Ocean, and Meteorological Satellite) is the geostationary satellite for the mission of satellite communication, ocean monitoring, and meteorological service. It is scheduled to be launched at the end of 2008. Ocean payload of COMS named as GOCI(Geostationary Ocean Color Imager) observes ocean color and derives the chlorophyll concentrlition, the concentration of dissolved organic material and so on. In operational oceanography, satellite derived data products are used to provide forecasting and now casting of the ocean and coastal water state. In this work, conceptual design of structural part of GOCI is carried out and two baseline concepts are proposed. The one is dioptric module that uses lens system and the other is TMA(Three Mirror Anastigmat) module that uses mirror system. Trade-off studies between two concepts are investigated by considering optical and mechanical performances. Finally, on-going tasks and future development plan are briefly discussed.

• Proceedings of the Optical Society of Korea Conference
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• 2003.02a
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• pp.98-99
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• 2003

2005년 국산 소형위성 발사체에 탑재되어 발사 될 예정으로, 과학기술위성2호의 개발이 2002년 10월부터 시작되었다. 과학기술위성2호는 약 100kg의 소형위성으로, 경사각 60～80$^{\circ}$의 300km x 1500km 타원궤도에 발사될 것으로 예상되고 있으며, 라만-a태양촬영망원경(LIST, Larman-a Imaging Solar Telescope)과 레이저정밀거리측정용 반사경이 각각 주 및 부 탑재체로 탑재될 예정이다. 위성레이저정밀거리측정(SLR, Satellite Laser Ranging)이란 위성간의 거리를 가장 정확하게 측정할수 있는 축지학적 기술이다. (중략)

• Bulletin of the Korean Space Science Society
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• 2008.10a
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• pp.28.3-28.3
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• 2008

Contamination has the potential for degrading the performance of the optical payload beyond the limits defined by mission requirements, therefore it must be considered a risk to system performance and must be mitigated. To mitigate contamination problem, contamination budget is allocated according to the contamination requirements which is derived from contamination effect analysis. Once the contamination budget is allocated, prediction for on-ground and in-orbit contaminants amounts and cleanliness control is performed. In this article, typical contamination control for observation satellite is described.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.12
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• pp.1232-1239
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• 2010

A high-resolution electro-optical camera (EOS-C Ver.3.0), the mission payload of an Earth observation satellite, is under development in Satrec Initiative. We designed this system to give improved thermal performance compared with the EOS-C Ver.2.0 which is the main payload of DubaiSat-1 by optimizing the active and passive thermal control design. We developed the Structural-Thermal Model (STM) and verified the design margin by performing the qualification level thermal vacuum test. We also conducted the verification of its Thermal Mathematical Model (TMM) through the thermal balance test. As a result, it was confirmed that TMM faithfully represents the thermal characteristics of the EOS-C Ver.3.0.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.12
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• pp.9-14
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• 2010

Using an IR (infrared) optical system of observation and research were performed long before. Nowadays satellites equipped with IR optical system observe the earth and universe. In this paper, we developed the IR optical system for main payload of the STSAT-3 (Science and Technology Satellite -3). We studied the ultra precision machining technique to fabricate FPL-53 lenses which is the IR optical material for space observation camera of the STSAT-3. DOE (Design of Experiment) was used to find best machining characteristic for FPL-53. Finally we fabricated FPL-53 aspheric lens with the form accuracy of P-V $0.36\;{\mu}m$.

• Korean Journal of Remote Sensing
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• v.16 no.4
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• pp.339-345
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• 2000

KOMPSAT-1 was launched on 21 December, 1999 and the main mission of the satellite is the cartography to provide the imagery from a remote earth view for the production of maps of Korean territory. For this purpose, the satellite has capability to tilt the spacecraft utmost $\pm$45 degrees to acquire stereo satellite imagery in different paths. This study aims to estimate the three dimensional positioning accuracy of stereo satellite imagery from EOC(electro-optical camera), a payload of KOMPSAT-1 satellite. For this purpose, the ground control points and check points were obtained by GPS surveying. The sensor modeling and the adjustment was performed by PCI software installed in KARI (Korea Aerospace Research Institute), which contained mathematical analysis module for KOMPSAT-1 EOC. The study areas were Taejon and Nonsan, placed in the middle part of Korea. As a result of this study, we found that the RMSE(root mean square error) value of three dimensional positioning KOMPST-1 stereo imagery can be less than 1 pixel (6.6 m) if we can use about 10 GCPs(ground control points). Then, a standarrd of FGDC (Federal Geographic Data Committee) of USA was applied to the result to estimate the three dimensional positioning accuracy of KOMPSAT-1 stereo imagery.

• Aerospace Engineering and Technology
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• v.4 no.2
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• pp.107-116
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• 2005

As a unique payload of Komsat-2, MSC, comprising EOS(Electro-Optical Sub-system), PMU(Payload Management Unit) and PDTS(Payload Data Transmission Sub-system), is supposed to take pictures of one panchromatic and 4 multi-spectral image between wavelength 450mm~900mm, and is being under final Satellite I&T. It will perform the earth remote sensing with applications such as acquisition of high resolution images, surveillance of large scale disasters and its countermeasure, survey of natural resources, etc.. Under the hostile influence of the extreme space environmental conditions due to deep space and direct solar flux, the thermal design is especially of major importance in designing a payload. There are tight temperature range restrictions for electro-optical elements while on the other hand there are low power consumption requirements due to the limited energy source on the spacecraft. This paper describes details of thermal control system for MSC.

• Journal of Aerospace System Engineering
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• v.12 no.1
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• pp.10-16
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• 2018

In 2018 and 2019, GEO-KOMPSAT-2A and GEO-KOMPSAT-2B will be launched in order to succeed the COMS mission. The two satellites will be collocated in $128.25{\pm}0.05$ degrees East. For precise ranging and orbit determination, the GEO-KOMPSAT-2B will be equipped with LRA (Laser Retroreflector Assembly) and SLR (Satellite Laser Ranging) systems will be utilized. This systems are located in Geochang. In this case, the laser beam emitted from the SLR station can cause problems in terms of safety of optical payloads and image quality. As a solution of this possibility, the laser ranging will be done during the night time when the shutters of the optical payloads remain closed. Still, the optical payload of the GEO-KOMPSAT-2A is not safe from the laser beam because its optical payload shall continue its mission for 24 hours a day. In order to handle this problem, the laser ranging shall be limited to time slots when the angular distance between two satellites observed from the Geochang SLR station is large enough. In this paper, through orbit simulations, the characteristics of variation of the angular distance between the two satellites is analyzed to figure out the time slots when laser ranging is allowed.

• 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.

• Journal of Astronomy and Space Sciences
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• v.20 no.3
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• pp.217-226
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• 2003

MSC (Multi-Spectral Camera) is the payload of KOMPSAT-2, which is being developed for earth imaging in optical and near-infrared region. The design of the MSC is completed and its reliability has been assessed from part level to the MSC system level. The reliability was analyzed in worst case and the analysis results showed that the value complies the required value of 0.9. In this paper, a calculation method of reliability for the MSC system is described, and assessment result is presented and discussed.