Gianfranco Morani , Francesco Nebula , Maria Pia Di Donato , Sara Di Benedetto , Johan Steelant
DOI Number XXX-YYY-ZZZ
Conference Number HiSST 2018_1860856
In the context of a funding by the European Space Agency (ESA) and the European Commission (EC) within the 7th Framework Program, the High-Speed Experimental Fly Vehicles – International (HEXAFLY-INT) project has the main objective to perform a flight validation of hypersonic technologies enabling future trans-atmospheric flights. The Experimental Flight Test Vehicle (named EFTV) is planned to be launched by the Brazilian VBS43 launcher, equipped with a S43 rocket engine which will perform a suborbital trajectory with an apogee at 90 km. After the release at 55km, the EFTV will perform a pull-out manoeuver bringing it to a levelled flight at an altitude of about 30km, where the experimental phase will start in hypersonic cruise at approximately Mach 7. This maneuver, combined with a lateral one, will be accomplished thanks to the onboard GNC algorithms, making the EFTV capable to perform a fully autonomous flight by using the aerodynamic control surfaces only. Generally speaking, the Flight Mechanics analyses are essential to investigate the open-loop vehicle flyability properties (trimability, controllability, etc.). Using this kind of analyses, the reference trajectory to be tracked by the GNC can be defined through a procedure capable to optimize a desired cost function along the trajectory itself respecting, at the same time, assigned constraints. The EFTV mission requirements – in terms of objectives and constraints – have been considered, as inputs, in the process of the trajectory generation. The aim of this paper is to describe the process of the EFTV trajectory generation and, in addition, to perform a dispersion analysis taking into account all the available uncertainties about vehicle mass, aerodynamics, measurement errors, etc.