• Journal of the Korean Society for Railway
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• v.8 no.4
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• pp.379-384
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• 2005

To maintain the stability during the operation of railway vehicle, the perfect installation of rail, namely the orbit as well as the performance of the railway vehicle itself is required. The orbit of railway needs the intensity and elasticity that stands the shock and vibration due to the weight of the railway vehicle enough, Also, the driving safety during the operation of vehicle should be guaranteed, comfortable feeling of the passenger should be maintained, and the influence of the noise and vibration to the environs should be minimized. Therefore, it is necessary to develop a program that calculates the change of construction cost according to the selection of railway orbit. This study introduces the orbit design automation program according to the selection of railway orbit, and discuss the principle and the way to use of the program.

• Proceedings of the KSR Conference
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• 2005.05a
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• pp.544-549
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• 2005

To maintain the stability during the operation of railway vehicle, the perfect installation of rail, namely the orbit as well as the performance of the railway vehicle itself is required. The orbit of railway needs the intensity and elasticity that stands the shock and vibration due to the weight of the railway vehicle enough. Also, the driving safety during the operation of vehicle should be guaranteed, comfortable feeling of the passenger should be maintained, and the influence of the noise and vibration to the environs should be minimized. Therefore, it is necessary to develop a program that calculates the change of construction cost according to the selection of railway orbit. This study introduces the orbit design automation program according to the selection of railway orbit, and discuss the principle and the way to use of the program.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.50 no.12
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• pp.867-875
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• 2022

The preliminary mission analysis of a lunar lander, which is mounted on the upper stage of a Korean space launch vehicle, is performed when landing on the moon through a trans-lunar injection maneuver after being injected into the earth's low orbit by th launcher in this paper. Both direct landing and orbital landing methods, which have each advantage and disadvantages, are applied and their transfer orbit characteristics are analyzed according to the launch date when launching in lunar October 2030. We also analyzed the launch dates which satisfying eclipse conditions, solar elevation conditions, and tracking time intervals such as the US lunar lander Surveyor-1. The obtained results show that the most appropriate launch date is the 4th day of lunar October in case of direct landing method, and the 3rd day in case of indirect landing method, since the argument of perigee of the trans-lunar injection orbit and eclipse conditions are favorable in the dates.

• Aerospace Engineering and Technology
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• v.5 no.2
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• pp.85-89
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• 2006

Propulsion System provides the required velocity change impulse for orbit transfer from parking orbit to mission orbit and three-axis vehicle attitude control impulse. New LEO Satellite propulsion system (PS) will be an all-welded, monopropellant hydrazine system. The PS consists of the subassemblies and components such as Thrusters, Propellant Tank, Pressure Transducer, Propellant Filter, Latching Isolation Valves, Fill/Drain Valves, interconnecting propellant line assembly, and thermal hardwares for operation-environment control of the PS. In this study, preliminary design process of LEO Satellite propulsion system will be summarized.

• Bulletin of the Korean Space Science Society
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• 2011.04a
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• pp.30.2-30.2
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• 2011

In this report, we present in-orbit radiometric performance prediction for the Amon-Ra (Albedo Monitor and Radiometer) energy channel instrument. The Integrated Ray Tracing (IRT) computational technique uses the ray sets arriving at the Amon-Ra instrument aperture orbiting around the L1 halo orbit. Using this, the variation of flux arriving at the energy channel detector was obtained when the Amon-Ra instrument including the energy channel design observes the Sun and Earth alternately. The flux detectability was verified at the energy channel detector (LME-500-A, InfraTecTM). The detector time response and RMS signal voltage were then derived from the simulated flux variation results. The computation results demonstrate that the designed energy channel optical system satisfies the in-orbit detectability requirement. The technical details of energy channel instrument design, IRT model construction, radiative transfer simulation and output signal computation results are presented together with future development plan.

• International Journal of Aeronautical and Space Sciences
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• v.17 no.4
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• pp.526-534
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• 2016

A MEMS solid propellant thruster array shall be operated within an allowable range of operating temperatures to avoid ignition failure by incomplete combustion due to a time delay in ignition. The structural safety of the MEMS thruster array under severe on-orbit thermal conditions can also be guaranteed by a suitable thermal control. In this study, we propose a thermal control strategy to perform on-orbit verification of a MEMS thruster module, which is expected to be the primary payload of the STEP Cube Lab mission. The strategy involves, the use of micro-igniters as heaters and temperature sensors for active thermal control because an additional heater cannot be implemented in the current design. In addition, we made efforts to reduce the launch loads transmitted to the MEMS thruster module at the system level structural design. The effectiveness of the proposed thermo-mechanical design strategy has been demonstrated by numerical analysis.

• Proceedings of the Korea Information Processing Society Conference
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• 2005.11a
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• pp.1355-1358
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• 2005

무선 이동 통신 환경에서 이동 단말기를 위한 CORBA 서비스를 제공하기 위한 방법으로 WAP(Wireless Application Protocol)을 이용하여 CORBA 클라이언트와 서버간의 통신을 하는 방법이 있다. 본 논문에서는 CORBA의 최소 구현 버전인 ORBit과 무선 인터넷에 적합한 WAP 스택을 구현한 Kannel WAP 게이트웨이를 이용하여 무선 이동 통신에 알맞은 환경을 제안한다. 이 환경은 ORBit을 사용하여 리소스의 크기가 작은 이동 단말기에 적합하다. 또한 WAP을 사용하여 TCP가 무선 환경에서 갑작스런 연결 종료와 전송지연에 대처하지 못하는 단점을 극복하고, CORBA 클라이언트와 서버간의 통신을 원활하게 한다.

• Proceedings of the KSRS Conference
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• 2007.10a
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• pp.41-44
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• 2007

Korea Aerospace Research Institute (KARI) has jointly developed a bipropellant propulsion system for Communication, Ocean and Meteorological Satellite (COMS) with EADS Astrium in UK. The technology relevant to a bipropellant propulsion system is quite new one in Korea, which is transferred for the first time, with development of COMS propulsion system. It hasn't ever attempted before, and hasn't got any general idea itself as well, in Korea. The COMS Chemical Propulsion System (CPS) is designed to perform both the orbital injection function, to take the spacecraft from transfer orbit to Geostationary Earth Orbit (GEO), and all on-station propulsive functions throughout the lifetime of the satellite. All station keeping manoeuvres are performed using the CPS. The design, manufacture and testing of COMS CPS are addressed in this paper. Feasibility of COMS CPS applicable to the other advanced mission is investigated as well.

• Journal of Astronomy and Space Sciences
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• v.34 no.2
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• pp.127-138
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• 2017

The current study designs the mission orbit of the lunar CubeSat spacecraft to measure the lunar local magnetic anomaly. To perform this mission, the CubeSat will impact the lunar surface over the Reiner Gamma swirl on the Moon. Orbit analyses are conducted comprising ${\Delta}V$ and error propagation analysis for the CubeSat mission orbit. First, three possible orbit scenarios are presented in terms of the CubeSat's impacting trajectories. For each scenario, it is important to achieve mission objectives with a minimum ${\Delta}V$ since the CubeSat is limited in size and cost. Therefore, the ${\Delta}V$ needed for the CubeSat to maneuver from the initial orbit toward the impacting trajectory is analyzed for each orbit scenario. In addition, error propagation analysis is performed for each scenario to evaluate how initial errors, such as position error, velocity error, and maneuver error, that occur when the CubeSat is separated from the lunar orbiter, eventually affect the final impact position. As a result, the current study adopts a CubeSat release from the circular orbit at 100 km altitude and an impact slope of $15^{\circ}$, among the possible impacting scenarios. For this scenario, the required ${\Delta}V$ is calculated as the result of the ${\Delta}V$ analysis. It can be used to practically make an estimate of this specific mission's fuel budget. In addition, the current study suggests error constraints for ${\Delta}V$ for the mission.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.03a
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• pp.283-292
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• 2008

The foremost criterion in the design of a Satellite Launch Vehicle(SLV) is its performance capability to boost the designated payload to the desired mission orbit; it starts from focusing on the SLV configuration to achieve the velocity requirements($}\Delta}V$) for the mission. In this paper we review an analytical approach which is suitable enough for preliminary conceptual design and is used previously to optimize stage configurations for Two Stage to Orbit SLV for Low Earth Orbit(LEO) Missions; we have extended this approach to Three Stage to Orbit SLV and compared different propellant options for the mission. The objective is to minimize the Gross Lift off Weight(GLOW). The primary performance figures of merit were the total inert weight of the SLV and the payload weight that the SLV could lift into LEO, given candidate propulsion systems. The optimization is achieved by configuring the $}\Delta}V$ between stages. A comparison of configurations of single-stage and multi-stage SLVs is made for different propellants. Based upon the optimized stage configurations a comparative performance analysis is made between Liquid and Solid fueled SLV. A 3 degree of freedom trajectory-analysis program is modeled in SIMULINK and used to conduct the performance analysis. Furthermore, a cost analysis is performed on our stage optimized SLVs. The cost estimation relationships(CER) used give us a comparison of development and fabrication costs for the Liquid vs. Solid fueled SLV in man years. The pros and cons of the production, operation ability, performance, responsiveness, logistics, price, shelf life, storage etc of both Solid and Liquid fueled SLVs are discussed. The statistics and data are used from existing or historical(real) SLV stages.