• Journal of the Korean Society of Propulsion Engineers
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• v.4 no.4
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• pp.107-113
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• 2000

Design configuration and performance requirements for KOMPSAT-1 propulsion system were described. Operational results of the propulsion system obtained through the satellite Launch and Early Operation Phase were scrutinized. Performance characteristics of the thrusters which are employed for spacecraft attitude control and the corresponding propellant depletion rate were analysed according to satellite operation modes. Additionally, propellant leakproof and thermal control capability were checked out from the view point of system verification. Propellant depletion rates calculated by PVT method in $\Delta$V maneuvering and each attitude control mode produce the very meaningful results for the prediction of total propellant consumption up to the end of satellite mission life.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.04a
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• pp.175-178
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• 2011

A performance characteristics and application status of liquid-monopropellants used for 3-axis control thrusters are surveyed, in this paper. Hydrogen peroxide was widely used as monopropellant until mid-1960s, but it is rapidly replaced with hydrazine which has better performance of specific impulse, storability, and so on. Hydrazine is mostly employed as a liquid-monopropellant of satellite, interplanetary spacecraft, and space launch vehicle owing to its moderate performance features.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.47 no.2
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• pp.55-59
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• 2010

Recently it is tried to use load control model for maneuver moving object. MIN design method proposed to solve control problem of nonlinear system using load concept. The Min design method shows direct method for finding control value on the load control model. In this paper, is shown realization free falling model using nonlinear load control model and analysis of load values acting falling object according to disturbance. And made a trajectory according to acting load values due to disturbance. This paper's result is able to be applied to design algorithm for improvement accuracy of MLRS, GPS air-to-surface missile(ASM) and returning spacecraft with nonlinear model predictive control.

• Journal of Satellite, Information and Communications
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• v.1 no.2
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• pp.16-24
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• 2006

As a multi-mission GEO satellite, COMS system is being developed jointly by KARI, ETRI, KORDI, KMA, and industries from both abroad and domestic. EADS ASRTIUM is the prime contractor for manufacturing the COMS. ETRI is developing the COMS Ka-band payload and SGCS with the fund from MIC. COMS Satellite Ground Control System (SGCS) will be the only system for monitor and control of the satellite in orbit. In order to fulfill the mission operations of the three payloads and spacecraft bus, COMS SGCS performs telemetry reception and processing, satellite tracking and ranging, command generation and transmission, satellite mission planning, flight dynamics operations, and satellite simulation, By the proper functional allocations, COMS SGCS is divided into five subsystems such as TTC, ROS, MPS, FDS, and CSS. In this paper, functional design of the COMS SGCS is described as five subsystems and the interfaces among the subsystems.

• Advances in aircraft and spacecraft science
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• v.5 no.2
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• pp.277-294
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• 2018

In the space industry, structures undergo several vibration and acoustic tests in order to verify their design and give confidence that they will survive the launch and other critical in-orbit dynamic scenarios. At component level, vibration tests are conducted with the aim to reach local or global interface loads without exceeding the design loads. So, it is often necessary to control and limit the input based on a load criterion. This means the test engineer should be able to assess the interface loads, even when load cannot be measured. This paper presents various approaches to evaluate interface loads using measured accelerations and by referring to mass operators. Various methods, from curve fitting techniques to finite element-based methods are presented. The methods are compared using signals with known imperfection to identify strengths and weaknesses of each mass operator definition.

• Advances in aircraft and spacecraft science
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• v.5 no.2
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• pp.251-258
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• 2018

This work illustrates the progress of a TAS activity at exploring the challenges and the benefits of the Virtual Shaker Testing (VST) approach. The definition and the validation of new computational methodologies with respect to the state of the art were encouraged throughout this activity. The shaker Finite Element (FE) model in lateral configuration was built for the purpose and it was merged with the SpaceCraft (S/C) FE model, together with the S/C-Shaker adapter. FE matrices were reduced through the Craig-Bampton method. The VST transient analysis was performed in MATLAB(R) numerical computing environment. The closed-loop vibration control is accounted for and the solution is obtained through the fourth-order Runge Kutta method. The use of pre-existing built-in functions was limited by authors with the aim of tracing the impact of all the problems' parameters in the solution. Assumptions and limitations of the proposed methodology are detailed throughout this paper. Some preliminary results pertaining to the current progress of the activity are thus illustrated before the conclusions.

• Transactions of the Korean Society of Mechanical Engineers
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• v.9 no.6
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• pp.801-809
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• 1985

다음 세대의 우주 비행선(spacecraft) 및 우주 구조물 등은 매우 정밀한 수행 능력은 물론 발사 경비의 절감을 위해 자체 무게를 최대한 줄일 수 있는 설계 방안을 요구하고 있다. 이같은 중 요한 요구 조건들을 만족시킬 수 있는 진동 제어의 한 방법으로써 재료 고유진동감쇠(material damping)의 효과적인 응용이 매우 중요시 되고 있다. 따라서, 본 연구에서는 열기류(Thermal currents)에 의해 발생하는 열탄성 진동감쇠(thermoelastic damping)를 연관 열탄성학(coupled thermoelasticity)에 근거하여 해석적으로 추정하고 진동감쇠율에 구조적, 기하학적 형태가 미치는 영향에 관해 고찰하였다. 단일 구조물의 형태, 경계조건 및 진동모우드 등이 진동감쇠에 미치는 영향을 새로운 계수로서 공식화 하였으며 아울러 최대 진동 감쇠율을 얻을 수 있는 최적조건을 고찰하였다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2005.11a
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• pp.426-430
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• 2005

The COMS(Communication, Ocean and Meteorological Satellite) is the first developed three-axis stabilization multi-function satellite on geostationary earth orbit(GEO) in korea, presently scheduled to be launched in 2008. The COMS propulsion system provides the thrust and torque required for the insertion into GEO, attitude and orbit control/adjustment of spacecraft. In this paper, system design of propulsion system, basic functions and design requirement of components are described.

• Journal of Aerospace System Engineering
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• v.2 no.4
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• pp.25-30
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• 2008

In general, we utilize momentum wheel to control spacecraft. It needs vacuum test to analyze the effect of space environments. The conventional vacuum connector which is composed of steel has problems for test with built in momentum wheel because of weight, thermal expansion, etc. We suggest possibility to manufacture the vacuum connector using aluminum mount, epoxy and industrial D-Sub considering cost, weight. We verify the performance through vacuum test.

• 제어로봇시스템학회:학술대회논문집
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• 1988.10a
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• pp.614-619
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• 1988

In this paper, an arbitrary mission of a spacecraft from launch to orbit injection is investigated for some launch trajectories. Launch sites are selected arbitrarily from various locations in Korea. For this study, a general purpose simulation program is developed. In this program, the Earth is assumed to be a rotating ellipsold. The launch vehicle is treated as a 3-D, 6-DOF rigid body. The developed program has been evaluated by calibrating it to the 3-stage N-1 rocket developed in Japan and launched at Tanegasima. The simulated trajectory from the first-stage ignition to burnout of third-stage main engine is compared with the previously tested N-1 rocket trajectory in Japan. The result shows that the program works properly. Using the proven program, we have investigated possible launch locations in Korea, namely Marado, Sungsan and Kuryongpo. The problem of polar orbit injection is also examined.