Conceptual Study on High-altitude Balloon Launch of Low Melting Point Thermoplastic Fuel/N_2O Hybrid Rocket

摘要

Hybrid rocket launched from a high-altitude balloon launcher is proposed. The propellants of the hybrid rocket motor are low-melting-point thermoplastic (LT) fuel and N_2O, which have advantages in their mechanical properties at cold temperature experienced in the high altitude environment. Three dimensional launch trajectory analyses were performed using single-stage or two-stage rockets designed with our developing hybrid rocket motor for science missions, for sampling of cosmic dust levitating over stratosphere. The apogee altitude can significantly be increased by elevating the altitude of launch point, because the disadvantage in low thrust level of hybrid rocket is solved by increasing the nozzle expansion ratio. Novel trajectories with two apogee points are presented that enable a long flight path in the upper atmosphere. The sequence of events of the proposed launch system and the main characteristics of the flight trajectories are reported.