Towed Reusable Launch Vehicle Flight Dynamics

The reuse of vehicle is the trend of the development of space transportation. There are many kinds of launch modes for reusable launch vehicles (RLVs), the air-launch is just one.In order to implement our development target of the space transportation system, that is "quick, flexible, cheap and reliable", the high-tech research and development program of China (863 program) has investigated all kinds of launch methods of transportation system. Under this project, we carried on an exploratory research of the two-stage-to-orbit transatmospheric vehicle and some key technology. This dissertation belongs to this research. The difficulties of the research came from the lack of references. So, every piece of the research findings is creative and exploratory.This dissertation reviewed and analyzed the history, current status and development trend of foreign RLVs in Japan, Europe, Russia, India and America. 3 kinds of air-launched methods and their performance advantages were introduced simply, including captive on top, aerial refueled, and towed. The concept design of the towed air-launched system was studied in detail according to the system characteristics. The towline in the towed air-launched vehicle system was researched in depth and finely. Many kinds of the towline mathematical models were founded. According to the coupling characteristics and constrained conditions of the towing system, the models of dynamics and kinematics of the towing system were built up. Some flight performances of the towing system were studied by simulation method. Finally, the static stability and the dynamic characteristics and flying quality of the vehicles in the towing system were analyzed and simulated. All creative research findings are showed as follows.1) Aiming at the technical order to the towed air-launched vehicle and the characteristics of the towing system, a concept design for a towed air-launch system is archived2) On the basis of the towing system's coupling characteristics constrained conditions, 6 kinds of mathematical models of the towline —a flexible body, are studied, which are linear spring, flexible suspended cable with rigidization, spring flexible body, equal distance restriction, flexible body with rigidization, and flexible body. The linear spring model and flexible suspended cable with rigidization model are applied in simulation calculation of the towing system.3) Based on dynamic and kinematic equations of the towing aircraft and towed vehicle and towline's mathematical models, the dynamic and kinematic equations of the towing system with three entities coupling and constrained are build.4) In the light of the dynamic and kinematic equations of the towing system, the trajectory control of the towed vehicle is studied, in order to achieve that the vehicle can follow the towing aircraft.