• Aerospace Engineering and Technology
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• v.2 no.1
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• pp.80-88
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• 2003

The present analysis quantifies the particulate contamination of KOMPSAT-2 satellite until in orbit life. Assumptions are defined about integration and test conditions and durations, then a budget is drawn. As KOMPSAT-2 activities are carried out in good cleanliness conditions, the particulate contamination budgets for satellite and instrument surfaces at BOL is fair. To summarise, in the baseline launch conditions (class 10,000) the contribution of satellite AIT and launch activities adds 500 PPM to MSC and STA apertures (telescope mirrors ; front lens ; baffle), 20,000 PPM to MSC and STA outer surfaces, 14 000 PPM to plate-form horizontal surfaces, 1400 PPM to plate-form vertical surfaces, 1000 PPM to plate-form radiators and less than 300 PPM to solar arra.

• Journal of KSNVE
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• v.27 no.1
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• pp.12-19
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• 2017

• Korean Journal of Remote Sensing
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• v.37 no.2
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• pp.359-365
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• 2021

GEO-KOMPSAT-2A (GK2A) AMI (Advanced Meteorological Imager) Best Detector Select (BDS) map is pre-determined and uploaded before the satellite launch. After the launch, there is some possibility of a detector performance change driven by an abrupt temperature variation and thus the status of BDS map needs to be evaluated and updated if necessary. To investigate performance of entire elements of the detectors, AMI BDS analyses were conducted based on a technical note provided from the AMI vendor (L3HARRIS). The concept of the BDS analysis is to investigate the stability of signals from detectors while they are staring at targets (deep space and internal calibration target). For this purpose, Long Time Series (LTS) and Output Voltage vs. Bias Voltage (V-V) methods are used. The LTS for 30 secs and the V-V for two secs are spanned respectively for looking at the targets to compute noise components of detectors. To get the necessary data sets, these activities were conducted during the In-Orbit Test (IOT) period since a normal operation of AMI is stopped and special mission plans are commanded. With collected data sets during the GK2A IOT, AMI BDS map was intensively examined. It was found that about 1% of entire detector elements, which were evaluated at the ground test, showed characteristic changes and those degraded elements are replaced by alternative best ones. The stripping effects on AMI raw images due to the BDS problem were clearly removed when the new BDS map was applied.

• Journal of the Korean Society of Propulsion Engineers
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• v.9 no.3
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• pp.133-144
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• 2005

Enhancements to propellants provide an opportunity to either increase performance of an existing launch vehicle. One of the promising technologies is the use of densified cryogenic propellants such as liquid hydrogen and liquid oxygen. The main advantage of densified cryogenic propellants is the increase in propellant mass fraction. Increased propellant mass fraction means increased payload mass to orbit. This paper reviews the basic principles and current technology trends for cryogenic propellant densification technologies. Several promising densification methods are presented focused on liquid oxygen densification. Engine and vehicle performance analyses are also presented to quantify the potential performance benefits of densified propellants in an overall system. And suggestions of application scheme for satellite launch vehicle is made.

• Journal of the Korean Society of Propulsion Engineers
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• v.25 no.3
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• pp.101-112
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• 2021

SpaceX shows various strategies such as constructing various payload portfolio through the reuse of Falcon 9 and Falcon Heavy, constructing the launch vehicles using one type of engine, the transition from kerosene engine to methane engine, and the use of 3D printing. In this study, launch vehicle proposals that can cover a variety of payloads and trajectories from KOMPSAT to GEO-KOMPSAT were constructed, and ten launch vehicles using kerosene gas generator cycle engine, kerosene staged-combustion cycle engine, and methane staged-combustion cycle engine were reviewed. Of the ten launch vehicles, the reusable launch vehicle using a 35-ton methane engine was rated as the best in terms of development potential.

• Electronics and Telecommunications Trends
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• v.10 no.4 s.38
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• pp.175-191
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• 1995

본 연구는 지금까지는 초보 단계에 머룰러 있지만 무궁화위성의 발사를 계기로 점차 활성화되고 있는 우리나라의 위성사업에 대해 먼저 알아보고, 이 위성사업의 기술적, 경제적 파급효과를 분석하였다. 위성 서비스 시장 규모는 초기에는 500억원 정도에 머물겠으나, 무궁화위성의 수명이 거의 끝나가는 2005년에는 약 1500억원 정도로 커질 것이다. 그리고 위성 관련 단말기 시장은 연간 1500억원 정도 될 것으로 예상된다. 특히 DBS 서비스와 위성 비디오통신 서비스는 서비스 시장의 2/3 이상을 차지하는 큰 시장이 될 것이며, DBS 수신기 시장도 성장 가능성이 매우 큰 분야이다. 무궁화위성은 우리나라를 위성 보유국의 대열에 낄 수 있게 하였으며, 위성 제작 기술 보유국이 되는 기반을 마련할 수 있게 하였다. 무궁화위성 이후의 위성사업계획과 연구 투자 계획에 비추어 볼 때, 2000년대가 되면 우리나라도 위성 발사체 분야를 제외한 대부분의 위성기술을 보유하는 나라가 될 것으로 예상된다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.66-68
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• 2011

Chollian is a geostationary satellite, and its bipropellant propulsion system is mainly composed of one main engine for orbit transfer and fourteen thrusters for on-station operations. The Chollian was launched successfully at Kourou Space Center in French Guiana. After it separated from the launcher, the propulsion system was initialised automatically. Then three times of main engine firing were successfully performed, and the target obit insertion was accomplished. This paper details the major CPS events during LEOP phase for the Chollian satellite.

• Journal of the Korean Society of Propulsion Engineers
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• v.22 no.2
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• pp.125-130
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• 2018

The technology development of a high performance upper stage engine for a GEO(GEostationary Orbit) KSLV(Korea Space Launch Vehicle) is undergoing in Korea Aerospace Research Institute. KSLV is composed of an open cycle engine with gas generator, which is for a low orbit launch vehicle. However the future GEO launch vehicle requires a high performance upper stage engine with a high specific impulse. The staged combustion cycle engine is necessary for this mission. In this paper, current progress and future plan for staged combustion cycle engine development is described.

• Satellite Communications and Space Industry
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• v.7 no.2 s.16
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• pp.34-46
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• 1999

한국통신은 현재 동경 116도 궤도에 무궁화1호 및 2호를 운영하며 통신 및 방송 서비스를 제공하고 있다. 무궁화 3호 위성은 대용량 위성으로 1/2호 위성의 중계기 용량을 모두 수용하며 동남아 지역을 대상으로 하는 가변빔 및 Ka-band 중계기를 탑재하고 있다. 3호 위성은 발사 후 동경 116도에 위치하여 올해로 수명이 다하는 1호 위성이 제공하는 서비스 및 2호 위성 서비스를 수용할 예정이며, 2호 위성은 113도로 이동하여 신규 서비스를 수용할 예정이다. 본 고에서는 무궁화3호 위성 탑재체의 설계사양 및 설계단계 성능분석에 대해 간략하게 소개하며, 분석결과와 실제 측정 데이터를 비교하였다. 또한 Ka-band 중계기의 주요 성능 파라미터들의 변화에 따라 디지털 통신캐리어를 가정하여 무궁화3호 위성 통신시스템의 비트오율 성능분석을 실시하였다. 시뮬레이션을 실시한 이유는 탑재체에 실제 서비스 캐리어가 실린 경우 탑재체의 통신품질을 예측하기 위함이다. 무궁화3호 위성의 공정현황 및 제공서비스에 대해서도 간략하게 소개하였다.

• Journal of Astronomy and Space Sciences
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• v.13 no.2
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• pp.105-116
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• 1996

This study is based upon the thermal modeling, analysis and operational results of KITSAT-1 and KITSAT-2 microsatellites launched on August 11, 1992 and Septermber 26, 1993, respectively. As KITSAT-1/2 was designed to be launched as an auxiliary payload of ARIANE launcher, the constraints on volume, power consumption, and mass were required to adopt passive thermal control method controlling absorptivity, emissivity, and conductivities among adjacent modules. The main of KITSAT was to take Earth images using CCD cameras positioned at the bottom of spacecraft, in which the cameras were always pointing to the center of Earth. This study is concerned with orbital analysis, thermal modeling, simulation results, and its verification by utilizing in-orbit telemetry data of KITSAT-2. The results of telemetry analysis show that the thermal modeling is matched to actual temperature data within 10 degrees of error range in average.