우주비행체 자세제어용 하이드라진 추력기의 성능특성 연구

Abstract

The propulsion system for attitude control of space vehicles can be classified into cold gas, monopropellant, bipropellant system. A trade-off study should be made for a selection of proper system among them, because each system has its own merits and disadvantages and there are a number of considerations to be taken, e.g., performance, mission capability, economic feasibility, safety, reliability, and so on. Hydrazine (N2H4), the currently representative monopropellant has merits such as long/stable storability, moderate specific impulse, easy throttling, low pollutants by plume, and low flame temperature. So, propulsion system utilizing hydrazine offers many advantages over the alternative approaches to performing the attitude control and station keeping function, though an application of bipropellant tends to increase recently along with the maturity of technology development. This paper summarized a ground hot-firing test results for the 70 N-class hydrazine thruster which may be employed in space launch vehicles. The thruster is designed to produce 67 N (15 lbf) 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. As results, it is confirmed that the thruster configuration was suitably designed for the requirement specified and it has excellent performance efficiencies.