• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.3
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• pp.72-78
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• 2003

In this paper, the feasibility study and the parametric design of hybrid motor with HTPB/LOX were conducted for micro air launch system. Design results were compared with 1st stage of Pegasus XL for verification of hybrid motor. Results showed that hybrid motor replace solid booster if Isp of hybrid motor reaches 330sec. In addition, mission analysis was established for micro air launch system, and parametric design was conducted with design variables: number of port, initial oxidizer flux, and chamber pressure. And the region of Isp was identified by parametric study which satisfied design constraints and mission analysis.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.45 no.1
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• pp.54-62
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• 2017

For the Earth observation satellite for ISR mission, a satellite constellation can be utilized to observe a specific area periodically and ultimately increase the effectiveness of the mission. The Walker-Delta method was applied to design constellation orbits with four satellites, which could detect abnormal activities in AoI(Area of Interest). To evaluate the effectiveness of the mission, a revisiting time was selected as a key requirement. This paper presents the mission analysis process for four SAR satellites constellation as well as the result of constellation configuration design to meet the requirements. Figure of Merits analysis was performed based on algorithm developed. Finally, it was confirmed that the constellation orbit with four different orbital planes is likely to be appropriate for ISR mission.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.9
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• pp.875-881
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• 2010

During the lunar mission, spacecraft are subject to various unexpected disturbance sources such as third body attraction, solar pressure and operating impulsive maneuver error. Therefore, efficient trajectory correction maneuver (TCM) strategy must be required to follow the designed mission trajectory. In the early days of space exploration, the mission trajectory has been designed by using patched conic approach based on two-body dynamics for the lunar mission. Thus the TCM based on two-body dynamics has been usually adopted. However, with the advanced in computing power, the mission trajectory based on three-body dynamics is attempted recently. Thus, these approaches based on two-body dynamics are essentially different from real environment and large amount of energy for the TCM is required. In this work, we study the trajectory correction maneuver based on three-body dynamics.

• Aerospace Engineering and Technology
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• v.4 no.2
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• pp.71-78
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• 2005

The purpose of FMECA is to identify parts and design whose damage can effect the mission performance and to improve the spacecraft design using these data. In consequence of this analysis, each failure mode which can be happened during operation and manufacturing period is identified, and their effects on mission performance are reviewed. In this technical report, the FMECA procedures and results for the satellite which is now under development are showed.

• Proceedings of the Korea Contents Association Conference
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• 2012.05a
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• pp.25-26
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• 2012

최근 하드웨어의 급속한 발달로 일상의 모든 기기와 시설에 컴퓨팅 장치가 내장되면서 임베디드 시스템의 중요성이 부각되고 있다. 임베디드 시스템은 특정 임무를 수행하기 위하여 설계된 전용 컴퓨팅 시스템으로 한정된 자원으로 인해 크기가 작은 커널이 필요하고 자원을 효율적으로 사용할 수 있어야 한다. 또한 특정 임무를 정해진 시간 안에 처리하기 위한 실시간성이 제공되어야 한다. 우선 순위 기반의 실시간 운영체제는 범용 운영체제 보다 커널의 크기가 작을 뿐만 아니라, 실시간성이 제공되기 때문에 임베디드 시스템에 많이 사용되고 있다. 본 논문에서는 실시간 운영체제인 uC/OSII에 보다 정확한 실시간성 제공을 위해 델타 프로세싱 기법을 설계 및 구현함으로써 uC/OSII의 시간 결정성을 보완하였다.

• Proceedings of the Korean Information Science Society Conference
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• 2006.06b
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• pp.166-168
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• 2006

현대전에서 보여지는 전쟁의 형태는 단기속결전으로 빠른 의사결정을 요구한다. 이러한 의사결정의 합리성과 객관성을 높이기 위해 선진국들은 의사결정 시스템을 제공하여 지휘관의 의사 결정을 돕고 있다. 본 논문은 이러한 임무수행 중 의사결정에 도움을 주기 위해 전문가 시스템을 이용한 의사결정지원 전문가시스템을 개념적으로 설계한다. 이를 위해 먼저 미군에서 널리 사용되고 있는 CPOF 의사결정 모델을 임무중심의 의사결정 모델로 전환하여 IDEFO 표기법을 사용하여 제시한다. 그리고 변경된 의사결정 모델 프로세스에 전문가시스템을 적용하여 의사결정지원 전문가시스템을 개념적으로 설계한다.

• Proceedings of the Korean Information Science Society Conference
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• 2006.10a
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• pp.248-252
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• 2006

최근 무인항공기는 정찰임무를 포함하여, 기상관측, 해상관측 등의 여러 임무로 사용되고 있으며, 점점 활용도가 높아지고 있다. 이러한 무인항공기 제어시스템은 과거에 비해 복잡도가 증가했으며, 보다 정밀한 실시간 제어가 요구되고 있다. 이러한 제어시스템을 위한 객체지향 설계방법론은 복잡한 모델에 대한 분석을 보다 빠르게 해주고, 재사용이 가능한 시스템 구축을 가능하게 해 줄 것이다. 이러한 목적을 위해 본 논문에서는 실시간 객체 모델인 TMO모델을 사용하여 시스템을 설계하고, TMO모델을 지원해 주는 리눅스 기반의 미들웨어를 사용하여 무인항공기 제어 시스템을 구현함으로써, 정밀한 실시간 제어시스템에 대한 TMO모델의 적합성을 판단하고, TMO모델 지원 미들웨어의 성능을 평가해 본다.

• Aerospace Engineering and Technology
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• v.7 no.1
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• pp.99-107
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• 2008

The COMS is a kind of geostationary multi-functional satellites with three different mission objectives. Two of them aim at earth observation and the COMS has two optical payloads according to those missions. The payloads are composed of a meteo imager and an ocean color imager, and their inherent characteristics require optimal interface design for their performance to be concurrently achieved. Therefore, various kinds of constraints are considered in their component accommodation on the COMS platform. This paper shows a general overview of the optical payload accommodation design and describes the design consideration to achieve the optimized performance from thermal and mechanical point of view.

• Journal of the Korean Society of Propulsion Engineers
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• v.17 no.1
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• pp.97-102
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• 2013

A prestudy on expendable turbine engine for high-speed vehicle was conducted. After two possible mission profiles were established to decide the engine requirements, design point analysis was performed with the values of design parameter which were obtained from similar class engines, references, etc. The results showed that specific net thrust and specific fuel consumption with turbine inlet temperature of 3,600 R are 2,599.4 ft/s and 1.483 lb/(lb*h) respectively at the flight condition of sea level, Mach 1.2. It was also found that major design parameters for determining maximum net thrust were turbine inlet temperature for low supersonic and transonic flight speed and compressor exit temperature for high supersonic flight speed from the results of performance analysis on the two possible mission profiles. In addition, simple turbojet engine with an axial compressor, a straight annular combustor, an one stage axial turbine and a fixed throat area converge-diverge exhaust nozzle was proposed as the configuration of simple low cost lightweight turbine engine.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.50 no.4
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• pp.277-285
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• 2022

There has been significant increase in demand of launch opportunities from the small satellite sector that represents the new space era. Providing smallsat-dedicated launch service at an affordable price is a new business model many startup companies have pursued, which requires innovative solutions for cost reduction in combination of low cost components, volume production and optimized manufacturing. We set out a preceding study at KARI to develop a suite of critical and cost-cutting technologies in preparation for a two-staged small launch vehicle development, based on the liquid rocket engine technologies developed from the Nuri program in accordance with the 3^rd master plan for national space development. In this work, we introduce the concept of a two-staged small launch vehicle that aims to be innovative and cost competitive for small satellites, and describe mission design results including staging as well as overall vehicle configuration of the launch vehicle.