ESA GNC Conference Papers Repository

The Italian Aerospace Research Centre is conducting an aerospace national research program named USV (Unmanned Space Vehicle), whose main objective is designing and manufacturing of unmanned Flying Test Beds (FTB), conceived as multi-mission flying laboratories, in order to develop and demonstrate innovative technologies for materials, structures, aerodynamics, guidance, navigation and control and critical operational aspects peculiar of the future Reusable Launch Vehicles (RLV) and aerospaceplane. Based on the velocity range under investigation, the whole USV program has been divided in parts, the first of which, named USV_1 project, relates to the subsonic, transonic and low supersonic regimes of flight. Specifically, transonic aerodynamic models and computational codes effectiveness, aerostructural behaviour knowledge and advanced autonomous guidance, navigation and control are the principal technology areas in which improvements are expected from the USV_1 program development. Two identical Flying Test Beds (FTB_1 configuration) have been designed and manufactured to support the USV_1 program execution, and the first flight mission has been already carried out, on a planned total number of three. From the Guidance, Navigation and Control systems perspective, the three missions will allow to develop and flight test the critical technology aspects related to autonomous execution of a typical TAEM (Terminal Area Energy Management) phase of a re-entry, from a velocity of about Mach 2 down to typical ALI (Approach/Landing Interface) speed of Mach 0.5 and below (actually, in the second mission the vehicle has to be slow down to Mach 0.2, before the activation of the recovery system). How technology advancements in the GN&C area can contribute to a more autonomous, more safe and less costly future generation of RLV is well stated in the open literature [1][2], and some of the more appealing technology improvements expected specifically for the TAEM phase [3], are identified. The most relevant technologies appear to be adaptive guidance techniques with on-line trajectory re-planning capabilities and robust and fault tolerant control techniques. They obviously also claim for improvements in robust analysis, design and verification techniques of such innovative GN&C systems for highly non-linear, time-varying and uncertain parameters plants. On this matter, much work has been done in Europe in the last decade as evidenced in [4]. All the above developments have been included in the CIRA technology road-map for flight demonstration in the context of the USV_1 project. Furthermore, technologies for Vehicle Model Identification from flight data have been also included in this road map, in order to maximize the feedback from the planned demonstration flights. Also in this area conventional techniques needs to be improved as only few flights can be performed, the trajectory is non stationary and specific identification manoeuvres should be avoided being highly risky for the mission.