Laser Controlled Solid Propellant Micro-thruster

这项研究的最终目标是完成一个小型火箭发动机的卫星（微推力器）具有高性能，可靠性和广泛的推力。我们提出的概念，实现这一目的是尝试通过使用固体推进剂的高性能，可靠性和简单性，再加上激光的燃烧开/关和推力水平控制。在这次的研究工作中，燃烧控制的基本原理是用一个最初制造的燃烧器进行实验确定的。结果表明，我们提出的设想是可行的：HTPB/AP富燃复合推进剂的激光强制燃烧在高压下具有与普通自燃推进剂相同的燃烧倾向，在较宽的压力范围内具有良好的燃烧控制性能。通过热成像测量的温度分布结合回归率给出了燃烧表面附近的热平衡，这反过来又表明，大部分传递到燃烧表面的热是由推进剂的化学反应提供的，激光只提供补充热流来补偿不足。根据阵列式火箭的概念，利用1 W激光二极管系统实现了固体推进剂（硼/硝酸钾）在真空中的激光点火。该火箭系统使用30 mg-1 g B/KNO推进剂可提供30 mNs-1 Ns的冲量。通过试验确定了适合阵发式火箭系统工作的混合比，优化了其性能。该火箭系统在真空中暴露2个月后成功运行，显示出其可用于实际太空任务的高可靠性。

The ultimate goal of this study is completion of a small rocket motor for satellites (micro-thruster) having high performance, reliability and wide range of thrust. Our proposing concept towards the purpose is tried by use of solid propellants for high performance, reliability and simplicity coupled with laser for the combustion on/off and thrust level control. In the research work of this time, the fundamentals of combustion control were experimentally ascertained using an originally made strand burner. The results revealed that our proposing concept is feasible: forced combustion of fuel rich HTPB/AP composite propellants by laser have the same tendency in burning behavior as ordinary self-combustible propellant under high pressures and a disposition good for combustion control in reasonably wide range of pressures. Measurements by thermography for the temperature distribution combined with regression rates gave the heat balance near the combustion surface which in turn suggested that most of the heat transferred to the burning surface is provided by chemical reaction of the propellants and laser supplies only supplementary heat flux to compensate for insufficiency. Regarding the concept of an array type rocket, laser ignition of solid propellant (Boron/Potassium nitrate)in vacuum has been realized using 1W laser diode system. This rocket system can provide an impulse of 30 mNs-1Ns using 30 mg-1 g B/KNO propellants. Mixture ratio suitable for the operation of the array type rocket system was experimentally determined to optimize its performance. This rocket system successfully operated after 2-month exposure in vacuum, showing its high reliability that can be used in actual space missions.