• Bulletin of the Korean Space Science Society
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• 2004.10b
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• pp.325-327
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• 2004

The longitudinal instability (POGO) of the rocket should not be occurred during the whole flight time for the large class liquid propulsion system to complete a mission successfully. The longitudinal instability is caused by the resonance between the propulsion system and rocket structure in the low frequency range below 50Hz, ordinarily. Analysis on the low frequency dynamic characteristics on the liquid propulsion system with staged combustion cycle engine system was performed as a preliminary study on the longitudinal instability analysis.

• Journal of the Korean Society of Propulsion Engineers
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• v.25 no.6
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• pp.53-59
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• 2021

The ROK Navy operates many war ships despite its short history. Various types of war ships, such as submarines, destroyers, frigates, corvette etc., use suitable propulsion systems for the operational requirements of each war ship. A hybrid propulsion system was introduced to change from the current mechanical propulsion system to an electric propulsion system according to the changing patterns of naval warfare, and it is expected that an integrated electric propulsion system will also be introduced. Therefore, this paper investigates the propulsion system of major ships operated by the Korean Navy, predicts the changes in future naval warfare, and proposes a propulsion system for future ships.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2002.04a
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• pp.10-13
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• 2002

Pogo is the instability resulting from the interaction between rocket structure and propulsion system of liquid propellant rocket. The coupling of structure and propulsion system can lead to severe problem in rocket. For the analysis of pogo, a time-invariant linearized mathematical model is developed for a selected flight time. Propulsion system is modeled using element representations for each components. The constitutive equation of propulsion system is a homogeneous second-order equation form in the Laplace domain. Rocket structure is modeled using FEM. From the results of modal analysis of structure, the behavior of structure can be represented. System equations for coupling structure and propulsion system are composed of all propulsion system equations and vehicle motion equations reacting on the vehicle by each component of propulsion system. The stability is obtained by the eigen solution of system matrix. The optimization of the design variables such as size, place of accumulator for suppressing pogo instability is carried out. This article of study can be used to determine the degree of stability, and guide the design of pogo suppression system.

• Journal of Aerospace System Engineering
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• v.2 no.1
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• pp.28-36
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• 2008

The technology relevant to a bipropellant propulsion system is quite new one in Korea, which is being 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 technical heritage of UK bipropellant propulsion pertinent to COMS propulsion system is scrutinised mainly. Furthermore the strong possibility of COMS CPS for the moon explorer mission is rationalised on the basis of the history of successful predecessors.

• Journal of the Society of Naval Architects of Korea
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• v.60 no.3
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• pp.175-185
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• 2023

Many small vessels such as fishing boats operate in the world's oceans; accordingly, interest in these small vessels' exhaust-gas problem is increasing. Research on the application of electric-propulsion technology has been steadily conducted; however, the subject is limited to research ships or leisure boats, while research on application efficiency remains insufficient. This study attempts to apply lithium-battery electric-propulsion technology to small ships. A gross tonnage of 9.77, a representative fishing boat, is to be redesigned as a fully electrified ship. Without changing the main cabin's dimensions and fuel tanks, the ship's propulsion system is redesigned based on a lithium-battery electric-propulsion system. In addition, the redesigned system is compared with the original sample ship's diesel-propulsion system for application-effect analysis. The results indicate that under controlled sailing conditions, the weight and volume of the electric-propulsion system are 9.5 and 10.5 times those of the diesel-propulsion system, respectively. These values indicate that the system cannot meet fishing boats' high endurance requirements. Therefore, under the existing technical conditions, applying the full lithium-battery electric-propulsion system to solve the problem of high emissions from fishing boats shows limited feasibility.

• Journal of the Korean Institute of Gas
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• v.10 no.4 s.33
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• pp.41-46
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• 2006

A study was conducted to investigate the problem caused by the mechanical particles in LOX system during operating and testing propulsion system, especially concentrated on effects of contaminants accumulation and transfer in LOX system. Several methods for system operation decreasing accidents caused by oxidizer Beakage and contaminants accumulation was investigated. These methods can be applied to LOX system and other propellants system in liquid propellants propulsion system.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.03a
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• pp.235-242
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• 2008

An innovative Panel ExTension SATellite(PETSAT) and propulsion system for PETSAT, are presented in this paper. First, we outline what PETSAT is. Next, based on PETSAT ethos, design policy of the propulsion system is provided. According to the policy, we designed propulsion system and concretely estimated and assembled mono-propellant and bi-propellant systems, and it indicated that mono-propellant propulsion with 50-60 seconds of specific impulse and 1 N of thrust is probable. In the case of bi-propellant, 120-150 seconds of specific impulse is valid even based on the design policy. We conducted captive tests of mono-propellant and bi-propellant propulsions with a breadboard model of propulsion system for PETSAT, and obtained good operations and performances. Based on the test results, we designed and manufactured flight model propulsion system for PETSAT. We are planning to demonstrate it in SOHLA-2L project progressed by the Space Oriented Higashiosaka Leading Association(SOHLA). SOHLA-2L will be the first on-orbit demonstrator of PETSAT in 2008.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.35 no.4
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• pp.323-328
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• 2007

A direct application of liquefied gas propellants to a typical small satellite cold gas propulsion system was analyzed. Performance of systems using liquefied gas propellant under consideration was compared to that of a nitrogen cold gas propulsion system. Liquefied gas propellant propulsion system's performance, required tank volume, and required propulsion system mass has been calculated at the same mass, volume, and total impulse condition of a typical nitrogen cold gas propulsion system. It was found that the liquefied gas propulsion system has advantages in performance, volume, and mass, compared to a typical nitrogen cold gas system, and can be directly applied to a cold gas propulsion system.

• Journal of Aerospace System Engineering
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• v.2 no.1
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• pp.37-45
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• 2008

KARI has jointly developed COMS bipropellant propulsion system with EADS Astrium, UK. It is well known at the moment about American or even German efforts for space development and space propulsion activities. On the contrary UK's capability for space development hasn't been recognised well in Korea. The major space activities relevant to the development of chemical and electric propulsion systems in UK, in reference to our space propulsion programme are addressed in detail. In addition the collaboration in prospect between two countries is proposed.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.581-584
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• 2010

Korea Aerospace Research Institute (KARI) started preliminary research about the propulsion system for lunar orbiter and moon lander this year in order to prepare korean moon exploration plan of 2020s. The final goal of this study is to develop a prototype propulsion system for lunar exploration and to perform ground landing test using this propulsion system. In this year, preliminary design of propulsion system and 200N class monopropellant thruster have been conducted. In this paper, the trade-off study result and the design concept of the propulsion system for Korean moon exploration will be introduced and preliminary design of propulsion system will be presented.