Basic Researches on Planetary Aerobrake Technology

研究的目的是建立与Aerobrake相关的基础技术，使行星探测器能够以相对少量的推进剂质量进入行星周围的轨道。其直接目的是利用地球轨道卫星进行技术演示和研究以氢气为主的行星大气中的气体动力学。在研究合同的最后一年，没有机会将演示器发射到地球轨道。飞行单元通过以下方式升级：包括重新编程能力，并通过几个单元的统一来减少质量。对非烟火分离装置进行了反复试验，直到证实了实施的可能性。延长杆已投入环境试验。在姿态-轨道控制方面，利用系绳运动建立了有效的轨道控制;在气体动力学方面，利用氢分子的旋转弛豫、振动弛豫和化学反应对氢高超声速稀薄气体进行了分析，为在木星大气中进行气动捕获提供了可行性。在实验中，采用爆轰激发膨胀管，高超声速氢气流量达到8 km/s。碳烧蚀体暴露于电弧加热的空气中，通过对产生的气体成分的光谱分析证实了火花的发生。为了科普强激波后的非定常大湍流，引入LES/RANS混合模型，建立了一种新的模型格式，提高了模型的精度。

The purpose of the research is to establish fundamental technologies related to Aerobrake which enables planetary explorers to be inserted into orbits around the planet with relatively small amount of propellant mass. The direct purposes are technology demonstration utilizing earth orbiting satellite and research of gas dynamics within planetary atmosphere which is dominated by hydrogen. In this last year of the research contract, an opportunity was not available to launch a demonstrator into earth orbit.The flight unit was upgraded by: inclusion of re-programming capability, and mass reduction through unification of several units. Non-pyrotechnic separation device was repeatedly tested until possibility of implementation was verified. Extension rod has been put into environmental tests. In the area of attitude-orbit control, an effective orbit control was established by utilizing tether motion.In the area of gas dynamics, hydrogen hypersonic rarefied gas analysis with hydrogen molecule rotation relaxation, vibration relaxation and chemical reactions provided feasibility of aerocapture in Jovian atmosphere. In the experiment, hypersonic hydrogen flow attained 8km/s with detonation invoked expansion tube. Carbon ablator was exposed to arc heated air and occurrence of spallation was confirmed through spectroscopic analysis of resultant gas components. To cope with a non-stationary large turbulence behind a strong shock wave, a novel model formulation was established introducing LES/RANS hybrid model which enhances precision.