• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.46 no.2
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• pp.175-181
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• 2018

Electric pump system is new technology for next generation propulsion unit. The system has simple structure which dose not need gas generator, injector and turbine and might better pump for low cost and low payload rocket. Therefore, this paper suggests conceptual design of electric-pump Permanent-Magnet Synchronous Motor (PMSM) which has 50 kW & 50,000 RPM for rocket. To satisfy the system's requirement, electromagnetic analysis is conducted for suitable inner and outer diameter of stator and rotor which uses 4000 Gauss cylinder magnet and Inconel 718 can to fix whole rotor. Futhermore, to confirm rotational vibration, rotordynamics analysis is conducted. By this analysis, Campbell diagram is printed. From the diagram, natural frequency could be determined for the only motor and dynamo meter test bench.

• Journal of computational fluids engineering
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• v.9 no.3
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• pp.49-56
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• 2004

A heated and expanded helium is used to pressurize liquid propellants in propellant tanks of propulsion system of liquid propellant launch vehicles. To produce a heated and expanded helium, an hot-gas heat exchanger is used by utilizing heat source from an exhausted gas, which was generated in a gas generator to operate turbine of turbo-pump and dumped out through an exhaust duct of engine. Both experimental and numerical approaches of hot-gas heat exchanger design were conducted in the present study. Experimentally, siliconites - electrical resistance types - were used to simulate the full heat condition instead of an exhausted gas. Cryogenic heat exchangers, which were immersed in a liquid nitrogen pool, were used to feed cryogenic gaseous helium in a hot-gas heat exchanger. Numerical simulation was made using commercially utilized solver - Fluent V.6.0 - to validate experimental results. Helically coiled stainless steel pipe and stainless steel exhausted duct were consisted of tetrahedron unstructured mesh. Helium was a working fluid Inside helical heat coil and regarded as an ideal gas. Realizable k-』 turbulent modeling was adopted to take turbulent mixing effects in consideration. Comparisons between experimental results and numerical solutions are Presented. It is observed that a resulted hot-gas heat exchanger design is reliable based on the comparison of both results.

• Aerospace Engineering and Technology
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• v.8 no.2
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• pp.98-104
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• 2009

A solid kick motor is used for propulsion system of KSLV-I 2nd stage. During combustion of the kick motor, vibration and shock could be generated. And it could be transferred to the vehicle equipment bay through the kick motor body. If vibration and shock transferred to the vehicle equipment bay are considerable, electrical equipments could be disordered. Therefore we need to verify influence of vibration and shock caused by combustion of the kick motor. In this research, we measured vibration of the kick motor on the ground firing test. Based on this measurement data, we analyzed random vibration and shock response spectrum.

• The Bulletin of The Korean Astronomical Society
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• v.36 no.2
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• pp.126.2-126.2
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• 2011

MIRIS(Multipurpose InfraRed Imaging System)는 과학기술위성 3호의 주 탑재체이며 2012년 하반기 발사예정이다. MIRIS 우주관측 카메라는 0.9-2.0 ${\mu}m$ 영역에서 3.67 deg. x 3.67 deg. FOV로 우리 은하평면 survey 관측과 우주배경복사(CIB) 관측을 수행할 것이다. 현재 MIRIS는 비행모델 개발 마무리 단계에 있으며, 검교정 시험, 열-진공 시험, 진동 시험 등을 수행하고 나면 2011년 말 위성 본체와의 조립을 진행할 것이다. 망원경이 복사냉각(Passive Cooling)을 통해 200K 이하로 냉각되면, dewar에 설치된 소형 냉각기를 가동하여 적외선 센서를 90K 정도로 냉각한다. MIRIS 우주관측카메라에는 PICNIC($256{\times}256$ pixel) 센서를 사용하였고, 상온과 냉각된 상태에서의 노이즈 특성을 측정하였다. PICNIC 센서와 dewar내부를 냉각하기 위해 RICOR사의 K-508 micro stirling cooler를 사용하는데, cooler가 동작하면서 전자부에 영향을 주어 주된 잡음으로 나타남을 확인하였다. Cooler에서 발생하는 잡음을 최소화 하기위해 fanout B/D와 LVPS 부분을 개선하였으며, 본 발표에서는 잡음 측정 결과에 대해 논의 하고자 한다.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.179.2-179.2
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• 2012

과학기술위성 3호는 우리 은하계의 근적외선 관측, 우주 배경복사 관측 및 지구 지표면의 적외선 영상 획득을 임무로 하는 우주관측용 적외선카메라와 지구 지표면의 적외선 영상획득을 임무로 하는 지구관측용 적외선카메라 그리고 한반도 지역의 다중 스펙트럼 영상을 획득함으로써 대기관측 및 환경감시의 임무를 가지는 소형분광영상카메라를 장착한 우주 및 지구과학 연구용 위성이다. 2007년 개발을 시작하여 시험인증모델(EQM, Engineering& Qualification Model) 개발과 열구조모델 (STM, Structure and Thermal Model)을 개발 완료하였고, 2012년 하반기에 발사를 앞두고 2010년 비행모델 유닛들이 납품되기 시작하여 위성체 시스템 레벨에서의 조립 및 시험을 진행하고 있다. 본 논문에서는 조립 및 기능시험 중 발견된 유닛의 문제들을 해결 과정과 시스템 레벨에서의 전기접합시험, 극성시험, 비행소프트웨어 기능시험, 종합기능시험 및 ETE 시험등 기능 시험의 종류, 목적 그리고 검증 결과를 발표하고자 한다.

• Journal of the Korean Society of Propulsion Engineers
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• v.14 no.4
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• pp.71-80
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• 2010

The KSLV-II(Korea Space Launch Vehicle-II) which being a successor of the KSLV-I is a space launch vehicle capable of delivering 1.5 ton-class satellite into a low earth orbit. The development of a 75 tonf-class liquid rocket engine(LRE) is planned on the basis of the technologies mastered through the preceded research of a 30 tonf-class LRE. The thrust chamber of the LRE is required to have higher combustion stability, structural integrity and thermal durability. This paper deals with the design requirements of the 75-tonf thrust chamber and a variety of technical considerations which have been conducted analytically in the course of the design for the realization of the requirements.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.6
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• pp.586-594
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• 2009

This paper is the study on random, sinusoidal and shock vibration responses for the STSAT-3(science and technology satellite-3) proto-model which is the first small size all-composite satellite in Korea. The structure system of the STSAT-3 forms box type structure by joining several hybrid sandwich panels comprised of honeycomb core and carbon fiber reinforced laminated composite skins on both side. Mode shape, stress, displacement and acceleration responses are obtained on both the frequency domain and time domain by means of a commercial FEA software MSC/NASTRAN. From these analysis results, failure, safety factor and design validity are assessed. These results can be successfully applicable as reference data when a new satellite is developed as well as giving out an excellent criteria in satellite vibration treatment design.

• The Korean Journal of Air & Space Law and Policy
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• v.25 no.1
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• pp.97-158
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• 2010

The purpose of this paper is to research on the contents and improvement of national legislations relating to space development in Korea to make the sustainable progress of space development project in Korea. Korea has launched its first satellite KITST-1 in 1992. The National Space Committee has established "The Space Development Promotion Basic Plan" in 2007. The plan addressed the development of total 13 satellites by 2010 and the space launch vehicle by 2020, and the launch of moon exploration spaceship by 2021. Korea has built the space center at Oinarodo, Goheng Province in June 2009. In Korea the first small launch vehicle KSLV-1 was launched at the Naro Space Center in August 2009, and its second launch was made in June 2010. The United Nations has adopted five treaties relating to the development of outer space as follows : The Outer Space Treaty of 1967, the Rescue and Return Agreement of 1968, the Liability Convention of 1972, the Registration Convention of 1974, and the Moon Treaty of 1979. All five treaties has come into force. Korea has ratified the Outer Space Treaty, the Rescue and Return Agreement, the Liability Convention and the Registration Convention excepting the Moon Treaty. Most of development countries have enacted the national legislation relating to the development of our space as follows : The National Aeronautic and Space Act of 1958 and the Commercial Space Act of 1998 in the United States, Outer Space Act of 1986 in England, Establishment Act of National Space Center of 1961 in France, Canadian Space Agency Act of 1990 in Canada, Space Basic Act of 2008 in Japan, and Law on Space Activity of 1993 in Russia. There are currently three national legislations relating to space development in Korea as follows : Aerospace Industry Development Promotion Act of 1987, Outer Space Development Promotion Act of 2005, Outer Space Damage Compensation Act of 2008. The Ministry of Knowledge Economy of Korea has announced the Full Amendment Draft of Aerospace Industry Development Promotion Act in December 2009, and it's main contents are as follows : (1) Changing the title of Act into Aerospace Industry Promotion Act, (2) Newly regulating the definition of air flight test place, etc., (3) Establishment of aerospace industry basic plan, establishment of aerospace industry committee, (4) Project for promoting aerospace industry, (5) Exploration development, international joint development, (6) Cooperative research development, (7) Mutual benefit project, (8) Project for furthering basis of aerospace industry, (9) Activating cluster of aerospace industry, (10) Designation of air flight test place, etc., (11) Abolishing the designation and assistance of specific enterprise, (12) Abolishing the inspection of performance and quality. The Outer Space Development Promotion Act should be revised with regard to the following matters : (1) Overlapping problem in legal system between the Outer Space Development Promotion Act and the Aerospace industry Development promotion Act, (2) Distribution and adjustment problem of the national research development budget for space development between National Space Committee and National Science Technology Committee, (3) Consideration and preservation of environment in space development, (4) Taking the legal action and maintaining the legal system for policy and regulation relating to space development. The Outer Space Damage Compensation Act should be revised with regard to the following matters : (1) Definition of space damage and indirect damage, (2) Currency unit of limit of compensation liability, (3) Joint liability and compensation claim right of launching person of space object, (4) Establishment of Space Damage Compensation Council. In Korea, it will be possible to make a space tourism in 2013, and it is planned to introduce and operate a manned spaceship in 2013. Therefore, it is necessary to develop the policy relating to the promotion of commercial space transportation industry. Also it is necessary to make the proper maintenance of the current Aviation Law and space development-related laws and regulations for the promotion of space transportation industry in Korea.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.6
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• pp.761-768
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• 2013

New warheads are designed and developed to be highly lethal when used as part of ballistic missile payloads. There are many trades associated with the design of a central warhead core, mainly dealing with the projectiles or penetrators. Obviously, a payload-type configuration is very susceptible to kills from one projectile because of the high impacts required for bomblet or submunition payloads. Based on these requirements, the optimum kill vehicle configuration will have the smallest mass and relative velocity that will kill all the submunitions. The designs of the penetrator shape and size are directly related to the space and weight of the warhead. The shape, size, L/D, penetrator material, and manner in which they are inserted inside the surrounding explosive segments are critical in achieving successful penetrator design. The AUTODYN-3D code was used to study the effect of penetrator penetration. The objective of numerical analysis was to determine the penetration characteristics of the penetrator produced by hypervelocity impacts under different initial conditions such as initial velocity, shape, and L/D of the penetrator.

• Journal of Aerospace System Engineering
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• v.18 no.1
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• pp.53-63
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• 2024

Adopting an engine igniter with high efficiency and ignition performance is essential for reliable operation of liquid rocket engines. In this study, we developed a spark torch igniter for a 450 N-scale methane-oxygen liquid rocket engine by conducting numerical analyses, igniter manufacturing and validation. Specifically, we conducted a parametric study for maximizing the enthalpy at the igniter exit, specifically by adjusting the mass flow rate, nozzle area ratio, fuel-oxidizer mixture ratio, and the igniter length-to-diameter. The heat transferred via the igniter nozzle exit was computed using 3-dimensional numerical simulations. We also manufactured and tested the igniter based on a deduced design to confirm ignition performance of the designed spark torch igniter. The igniter developed through this study could contribute to the development of practical propulsion systems such as upper-stage engines of small launch vehicles.