An Extrapolation from Flight Methodology for a Re-Entry Vehicle Wing Leading Edge Test in a Plasma Wind Tunnel Facility

Abstract

Within the frame of the Advanced Structural Assembly (ASA) project funded by the Italian Space Agency and with Thales Alenia Space as prime, CIRA (Italian Aerospace Research Centre) will perform a series of Plasma Wind Tunnel Test in its facility “Scirocco” over a Test Article representative of the wing of the future experimental Flight Test Bed, named FTB-X. The validation and the qualification of thermal protection system technologies, developed to face repeated re-entry missions or a sustained hypersonic velocity of a space vehicle, can be done in a plasma wind tunnel by reproducing the flight thermal loads on a representative model. The on-ground high enthalpy facilities do not allow the simultaneous reproduction of all the thermo-fluid-dynamics conditions that characterize above all the low-earth orbit part of a typical space vehicle re-entry trajectory because it may be difficult to contemporary reproduce both heat flux and pressure. Moreover, the correct reproduction of heat flux and pressure at the stagnation point do not assure in general that we are simulating the same environment downstream of the stagnation point itself with respect to the flight conditions because of differences of the unit Reynolds number and Mach number. For all the above reasons an extensive theoretical-numerical analysis is necessary both for the extrapolation from simulated flight conditions to suitable plasma wind tunnel operating conditions (extrapolation-from-flight ), and for the extrapolation of the test results to flight conditions (extrapolation-to-flight ). The developed extrapolation from flight methodology, presented in this paper, has been applied to the design of a test campaign on a large scale wing leading edge model. Aim of this test campaign is to qualify different innovative TPS concepts with an aero-thermal environment as much as possible representative of the flight conditions that vehicle FTB-X will experience during the re-entry mission.