• Aerospace Engineering and Technology
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• v.10 no.1
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• pp.156-166
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• 2011

COMS (Communication Ocean and Meteorological Satellite), the Korea's first geostationary Earth observation satellite, started to operate 24 hours to observe Land/Ocean/Atmosphere with the MI (Meteorological Imager) and GOCI (Geostationary Ocean Color Imager). After the successful completion of the IOT (In-Orbit Test), the satellite is in normal operation from April of 2011. This paper describes an algorithm for scan mirror emissivity compensation of the COMS MI and its software implementation.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.194.2-194.2
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• 2012

Korea Aerospace Research Institute has developed an earth observation satellite and it was launched into its orbit in 2012 by using a foreign commercial launch vehicle. The launch site authority has imposed safety requirements to the spacecraft developer to ensure the safety of the personnel and to protect launch vehicle, spacecraft and facilities from accidents associated with the satellite operation at the launch site. This paper describes the range safety activities implemented for the satellite and supporting equipments during the whole phase of their design, manufacturing/test and operation at the launch site. To ensure the integrated requirements for safety management and design, system safety program plan has been developed. And based upon the plan, spacecraft developer conducted hazard analysis to identify and establish safety requirements to reflect in designs, procedures, operations. The result of the hazard analysis has been complied into safety data packages and it was reviewed by launch site review board at the safety reviews and finally it was approved to launch.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.125-131
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• 2008

This research tries to analyze and investigate the effects of the noise reduction test for the sound-absorbing materials installed tentatively on Metro Line 5. Though the noise reduction effects of each sound-absorbing material showed that there was about $2{\sim}5\;dB$ compared with before and after of the tentative installation, it shows that the noise reduction effects are reducing because of the section change condition such as dust absorption and the rail abrasion as time passes after the tentative installation. Also, many difficulties are occurring in the maintenance of the orbit facilities because of the installation of sound-absorbing materials. Though various abroad products for noise reduction are imported like this, the researches for the noise reduction effect increase for this and the improvement direction are being required because of the poor circumstance of the efficiency aspect compared to the economic investment effect because those are not suited to the character of domestic Metro.

• 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.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.949-952
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• 2005

According to the national space program in Korea, is satellites will be launch into space up to 2015. Especially, KARI is going to develope of its own a high resolution camera of less than 1m to be mounted on next Multipurpose Satellite. When performing testing of large spacecraft or hardware that will be launched into orbit, it is necessary to conduct a testing with space-simulated environment. To achieve this requirement, thermal vacuum chamber is generally used. KARI has been developed a very Large Thermal Vacuum Chamber(LTVC) from 2003 to accomodate future space program, such as KOMPSAT, COMS, and Launch vehicles. This new facility will be used to qualify the first self developed High Resolution Camera, which will be loaded on KOMPSAT-3. To perform an optical test for space camera, it is necessary to provide vibration free environment. Thus the vibration responses on the optical table due to external vibration should be minimized by using a special isolation system. In this paper, we propose the concept design of vibration isolation system for the development of the high resolution camera.

• Journal of Astronomy and Space Sciences
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• v.37 no.3
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• pp.199-208
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• 2020

This paper presents a kinematic ephemeris generator for Korea Pathfinder Lunar Orbiter (KPLO) and its performance test results. The kinematic ephemeris generator consists of a ground ephemeris compressor and an onboard ephemeris calculator. The ground ephemeris compressor has to compress desired orbit propagation data by using an interpolation method in a ground system. The onboard ephemeris calculator can generate spacecraft ephemeris and the Sun/Moon ephemeris in onboard computer of the KPLO. Among many interpolation methods, polynomial interpolation with uniform node, Chebyshev interpolation, Hermite interpolation are tested for their performances. As a result of the test, it is shown that all the methods have some cases that meet requirements but there are some performance differences. It is also confirmed that, the Chebyshev interpolation shows better performance than other methods for spacecraft ephemeris generation, and the polynomial interpolation with uniform nodes yields good performance for the Sun/Moon ephemeris generation. Based on these results, a Kinematic ephemeris generator is developed for the KPLO mission. Then, the developed ephemeris generator can find an approximating function using interpolation method considering the size and accuracy of the data to be transmitted.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.35 no.9
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• pp.850-857
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• 2007

The design and analysis of satellite electrical power subsystem is an important driver for the mass, size, and capability of the satellite. In particular, satellite energy balance analysis is critical in determining the capabilities and limitations of the power subsystem and the success of satellite operations. This paper introduces a new energy balance analysis program for LEO satellite development and shows an example of test results using other LEO satellite design data. The test results show that the proposed energy balance program can be used the optimal sizing of satellite electrical power subsystem and the analytical prediction of the on-orbit energy balance during satellite mission operations.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.598-602
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• 2017

Korea Aerospace Research Institute has been developing 3-stage launcher KSLV-II, which can inject 1.5-ton satellite into sun synchronous orbit (SSO). For development process, Test Launch Vehicle(TLV) adopting the $2^{nd}$ and $3^{rd}$ stage of KSLV-II will be scheduled to launch in 2018. The propulsion system of TLV is composed of $2^{nd}$ stage engine system (ground type) and propellant supply system including LOX, Kerosene tanks. Until now, system integration of engineering model of TLV and delivery of qualification model have been done. In this paper, the product assurance activities for propulsion system KSLV-II will be illustrated.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.50 no.10
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• pp.729-737
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• 2022

Melting and icing process of the PCMTCU(Phase Change Material Thermal Control Unit) installed on the NEXTSat-2, which is scheduled to be launched in the second half, was investigated through the results of satellite-level TVT(Thermal Vacuum Test). As a result of the test, it was confirmed that the latent heat of PCM contributes to the temperature stabilization of the heating components. The thermal model for numerical analysis of the PCMTCU was correlated to acquire a reasonable degree of accuracy using the collected temperature measurements during TVT. The periodic temperature variation of the PCMTCU in normal on-orbit operation was predicted with the correlated thermal model, and the quantitative contribution of the PCM on the thermal energy management was evaluated with the liquid fraction. It will receive flight telemetry from the NEXTSat-2 after the launch, and complete the space verification of the PCMTCU.

• Bulletin of the Korean Space Science Society
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• 2011.04a
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• pp.24.2-24.2
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• 2011

천리안위성은 2010년 6월 27일에 발사되어 성공적으로 In Orbit Test (IOT)를 수행하고 있다. 천리안 위성을 지상에서 컨트롤 하기 위하여 ETRI 에서는 위성관제시스템을 개발하였으며, 현재 KARI에서 위성관제시스템을 운영중이다. 위성관제시스템의 일부인 임무계획 시스템은 기상/해양 이미지 촬영에 관한 임무요청, 위성체 기동 요청, 각동 이벤트 등을 종합하여 충돌 없는 임무스케줄을 만들어내게 되는데 이에 복잡한 스케줄링 기법이 요구된다. 천리안 위성의 임무 스케줄링 기법은 CPU 연산을 기본으로 하고 있으나, 이 논문에서는 Graphics Processing Units(GPU) 를 통한 임무 스케줄링 기법의 적용에 따르는 고려사항을 설명한다. 그리고 CPU 기반의 임무 스케줄링 기법과 GPU 기반의 임무 스케줄링 기법의 장단점을 분석한다.