• Bulletin of the Korean Space Science Society
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• 2009.10a
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• pp.45.3-46
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• 2009

홀 추력기는 비교적 간단한 구조와 작은 크기 및 높은 연료효율로 미래 소형위성의 핵심기술로 주목 받고 있다. 이 연구실에서는 2010년 발사예정인 과학기술위성 3호에 탑재할 소형위성용 저 전력 홀 추력기를 연구 개발하였다. 성능에 가장 큰 영향을 미치는 자기장 구조는 FEMM전산코드를 이용한 해석을 통해 설계되었으며, 제작된 프로토타입의 실험을 통해 자기장의 세기 및 모양, 양극전압 및 기체유량에 따른 성능 특성을 관찰하였다. 또한 Faraday Probe와 Retarding Potential Analyzer (RPA), 랑뮈어 탐침 등을 이용해 이온빔의 분사각도 및 전류밀도, 이온에너지 분포, 플라즈마 전위 등을 측정하고 관찰된 특성을 물리적으로 분석하였다. 이러한 최적화 과정을 통해 설계된 비행모델의 시험 결과 양극전력 200 W, 제논 연료유량 0.85 mg/s 을 통해 11.2 mN 추력, 1350 s 비추력, 37% 추력효율을 획득하여 개발목표를 상회하는 만족할만한 결과를 얻었다.

• Journal of the Korean Society of Propulsion Engineers
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• v.12 no.3
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• pp.24-33
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• 2008

A 50 Newton monopropellant thruster being developed for attitude control in a variety of aerospace application systems is described in this paper. A scaled down thruster with platinum on aluminum oxide in the reaction chamber was tested to determine the catalyst capacity. A scaled up thruster which was designed and fabricated using data obtained from a small scale device was evaluated by its decomposition efficiency based on the temperature, the efficiency of characteristic velocity, and the measurement of thrust. The performance of a scaled up thruster was marked by a measured thrust of 42 Newton, 98 % efficiency of the characteristic velocity, a specific impulse of 123 sec at sea level.

• Journal of the Korean Society of Propulsion Engineers
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• v.11 no.4
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• pp.67-73
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• 2007

In recent years hydrogen peroxide has become considerably more attractive as a green rocket propellant so a laboratory model of hydrogen peroxide thruster adopted silver catalyst and a test facility has been developed to research a hydrogen peroxide propulsion. The design scheme of thruster and the test data are presented including ignition delay, efficiency of characteristic exhaust velocity. As a result, 95% of efficiency of characteristic exhaust velocity was obtained at steady state operation condition.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.05a
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• pp.111-114
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• 2008

The performance evaluation of a micro monopropellant thruster is described in this paper. The platinum which has stable physical and chemical properties is used as a catalyst. The ceramic form, named Isolite is chosen as a catalyst bed. Hydrogen peroxide whose concentration is up to 90wt% is supplied into thruster by direct pressurization with nitrogen gas. The $c^*$ efficient is calculated to evaluate the performance of a thruster. The pressure rise time, pressure decent time and reaction delay are synthetically considered.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.5
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• pp.490-495
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• 2009

A small Hall-effect thruster with a thrust range near 10 mN and a specific impulse of about 1500 s has been designed to control or maintain the orbits of small satellites. The thruster system consists of a hall-effect thruster head, a power processing unit and a Xenon (Xe) gas feed system. The total mass, the consumed electric power and the efficiency of the thruster are approximately 10 kg, 300W and 30%, respectively. Analyses results that support the selection of the thruster for small satellites are provided along with a brief description of the thruster system.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.645-648
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• 2011

Hydrazine which has been used as monopropellant shows high performance, but because of its high toxicity research for new green propellant that could replace hydrazine is going on. Ionic liquid propellant that is one of the green propellant has lower toxicity, higher specific impulse, and higher density than hydrazine. To design the thruster which use Hydroxylamine Nitrate (HAN), one of ionic liquid propellant, as a propellant, a quantity of catalyst for full decomposition of a propellant is needed. In this study, reference point for HAN thruster design could be suggested through a design of a small scale thruster which used HAN propellant, and propellant decomposition capability evaluation with characteristic velocity efficiency.

• Journal of the Korean Society of Propulsion Engineers
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• v.16 no.6
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• pp.48-55
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• 2012

An ambient hot-firing test was carried out for the hydrazine thruster which may be employed in the space launch vehicles. The thruster is designed to produce 67 N (15 $lb_f$) of nominal steady-state thrust at an inlet pressure of 2.41 MPa (350 psia). A scrutiny into the performance characteristics of thruster is made in terms of thrust, propellant supply pressure, mass flow rate, chamber pressure, and temperature at the steady-state firing mode. As a result, it is ensured that the practical performance efficiencies are above 89.1% compared to its ideal requirements.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.196.2-196.2
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• 2012

본 논문은 달착륙선의 개념설계를 위하여 고려한 전력시스템의 설계와 달착륙선의 지상시험모델용 추력기 밸브구동 전원장치 개발에 대해 기술하였다. 달착륙선의 임무특성을 고려하여 전력시스템의 구조를 검토하고, 극한의 온도환경에서 달착륙선의 임무수행을 위하여 필요한 전력에너지를 충분히 공급할 수 있도록 태양전지 배열기와 배터리의 용량, 그리고 전장품의 용량을 설계하였다. 특히 경량의 달착륙선 개발을 위하여 고효율의 태양전지를 이용한 태양전지 배열기와 리튬-이온 배터리를 검토하였다. 극한의 우주환경에서 태양전지배열기의 동작특성을 검토하고 생성될 수 있는 최대 전력을 분석하여 최적의 태양전지 배열기의 면적을 분석하고, 장시간의 월식을 고려하여 배터리의 방전특성에 따른 배터리의 전압특성을 검토하였다. 그리고 달착륙선의 전력시스템 개념설계의 타당성 검토를 위하여 유럽에서 개념설계 중인 달착륙선의 전력시스템 사양과 용량에 대해 비교검토를 수행하였다. 현재 개발중인 지상검증모델용 달착륙선의 전력시스템 설계와 추력기 밸브구동 전원장치의 개발에 관해 기술하였다. 지상검증용 전력시스템은 태양전지배열기의 장착 없이 배터리의 전력만을 사용하여 지상검증모델용 달착륙선의 부하에 전력을 공급할 수 있도록 설계되었다. 달착륙선 지상시험모델의 비행시간과 임무에 따른 부하특성을 고려하여 상용 리튬-이온 배터리의 용량을 선정하였으며, 부하의 전력을 고려하여 간단한 보호회로를 설계하였다. 그리고 지상검증용 전원시스템은 추력기의 밸브구동을 위한 추력기 밸브구동 전원장치, DC/DC 컨버터 전원 모듈, 모니터링 모듈, 그리고 위급상황에서 전원을 차단하기 위한 "Emergency STOP" 모듈로 구성되어 있다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2007.04a
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• pp.102-105
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• 2007

The performance evaluation of the micro thruster utilizing hydrogen peroxide decomposition is described. The catalyst bed was made of porous ceramic material($Isolite^{(R)}$) with large surface to mass ratio. 14%wt platinum was loaded on the catalyst support as a catalyst. Hydrogen peroxide with 85% concentration was used as a monopropellant. The length of the catalyst bed and the feed pressure of the hydrogen peroxide were taken as the parameters for the experiment. All experiments were carried out under cold start condition for 30 seconds. The $c^*$ efficiency was evaluated for each test case using measured pressure data. For the catalyst support length of 30 mm and feed pressure at 5.51 bar, satisfactory $c^*$ efficiency beyond 95% was observed.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.5
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• pp.496-501
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• 2009

The thruster head unit of a 300 W cylindrical Hall thruster was developed for the propulsion system of small satellites. The magnetic topology in the thruster channel is a key parameter to achieve high performances. Two types of magnetic circuit structures were designed and manufactured to compare the thrust levels and efficiencies. Also the endurance test was conducted to measure the stable operation duration of the thruster head and to find degree of erosion after extended operation.