A small scale low cost technology demonstrator of a reusable launch vehicle

Recent years have seen an increasing interest of the scientific community toward the study and development of unmanned automatic vehicles, also in the Reusable Launch Vehicle (RLV) frame. Indeed, a number of unmanned vehicle projects have been devoted to demonstrate some key aspects of the technological challenges related to an autonomous RLV. The major efforts have been undertaken by NASA, with the past X-33 and X-34 programs. However, because of the high funding required by the development of a cost-effective completely reusable vehicle, current efforts are focused on developing demonstrators of some critical technologies of such a vehicle. Recent examples are the successful NASA's X-37/X-40 and DLR's Phoenix5, testing autonomous landing of an RLV-shaped vehicle, and the NASA X-43A6, testing air-breathing propulsion. In this framework, the Unmanned Space Vehicle (USV) Program7 is being performed by the Italian Aerospace Research Centre (CIRA). The USV Program main focus is on the development and in-flight testing of critical technologies of autonomous, fully re-usable, winged-body launch vehicles. To this end, three vehicles, named Flight Test Beds (FTB), will perform a number of missions aimed at gaining further insight into transonic and hypersonic flight, sub-orbital and orbital re-entry, guidance navigation and control, innovative thermal protection systems. In this context, a phase-A study of a low-cost reduced-scale technology demonstrator of a RLV has been carried out by research teams at Politecnico of Turin and at the universities of Naples and Rome under CIRA funding. The main goal of the study was to assess the feasibility of a reduced scale (1:5) technology demonstrator aiming at validating some critical technological and operational aspects of RLVs and of the USV program, by taking the Suborbital Re-entry Test (SRT) mission as case study. The SRT mission main objective is flying at thermal fluxes higher than 650 kW/m2 at the stagnation point for a time interval at least of 15 s ("hot time"), in order to test innovative Thermal Protection System (TPS) technologies. The vehicle, conceived as a result of the phase-A studies, is a two-stage system. The first stage consists of an expendable off-the-shelf solid propellant motor while the second stage is a non-propelled glider, whose aerodynamic shape is a scaled version of the full-scale USV vehicle. As a result of the phase-A studies, two candidate configurations have been identified for the vehicle, one (A) designed to attain high performance, in terms of similarity with SRT, the other (B), taken as baseline configuration, to reduce system complexity and, mainly, cost. Copyright © 2005 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.