Masakazu Sagisaka

RECOVERY GUIDANCE FOR THE HIGH SPEED FLIGHT DEMONSTRATION VEHICLE

A High-Speed Flight Demonstration (HSFD) program is planned as part of research for the HOPE-X unmanned re-entry vehicle project. The program consists of two phases, and the objective of Phase II is to estimate the transonic aerodynamic characteristics of the HOPE-X configuration. The experimental method for Phase n is highly unique: the experiment vehicle is to be lifted to high altitude by a stratospheric balloon, from which it will be released and accelerate in free fall. During data acquisition, the vehicle will fly at a constant Mach number. After data acquisition, the vehicle will be recovered using parachute and airbag systems, and refurbished for the next flight. The flight of the vehicle is fully autonomous under the navigation, guidance and control (GNC) of its on-board computer, and it is one of important missions for the GNC system to guide the vehicle to a designated recovery point with final flight conditions suitable for deploying a recovery parachute. A guidance system which satisfies this requirement was designed and a six degree-of-freedom flight simulation analysis including mathematical model errors was carried out to evaluate it. The results show that the vehicle can be guided to the target point within the required accuracy by the designed guidance system. NOMENCLATURE