PAYLOADS ON BOARD THE EUROPEAN EXPERIMENTAL RE-ENTRY TEST BED EXPERT: STATUS OF DEVELOPMENT AND FUTURE ACTIVITIES

摘要

The European Experimental Re-entry Test-bed EXPERT is developed by the European Space Agency (ESA) as part of its General Technological Research Program (GSTP). The aim of EXPERT is to improve the understanding of critical aero-thermodynamic phenomena associated with hypersonic re-entry flights. The EXPERT project provides an opportunity to the scientific community and industries throughout Europe to propose and perform experiments in order to obtain aero-thermodynamic data for the validation of numerical models and of ground to flight extrapolation methodologies. During the last years, an intense activity has been performed at ESA in order to select the most suitable experiments, bring them to a mature flight design, and coordinate and optimize the work among the principal investigators throughout Europe so that the scientific output can be maximized within the allocated budget and the programmatic constraints of the EXPERT project. EXPERT is a re-entry capsule having the shape of a blunted cone. The front part consists of a nose made of ceramic material developed at DLR Stuttgart. No ablative material is implemented so as not to contaminate the specific measurements of Payloads on board. The ceramic nose hosts a set of experiments: the Flush Air Data System (FADS) developed by HTG aiming at collecting free flow data required for post flight analysis, the pyrometer PYREX developed at IRS in Stuttgart collecting data on the temperature and heat flux of the ceramic nose, and the IRS spectrometer RESPECT aiming at resolving the different species generated in the plasma region during re-entry. The sides of the blunted cone are protected by a metallic thermal protection system in which several experiments are located. Two Payloads developed by IRS and VKI are dedicated to the measurement of catalytic effects. One aims at detecting the catalytic jump in wall temperature between the ceramic and the metallic region, and one aims at testing different material samples to derive their catalytic properties. Two Payloads developed by CIRA and VKI are dedicated to the detection respectively of the natural laminar to turbulent transition and the roughness induced transition with a triggering element. An experiment developed at TU Delft aims at testing the efficiency of an innovative radiation cooling technique. In the lower part of the vehicle four flaps are present. A Payload developed by CIRA is devoted to the characterization of the interaction between shock wave and boundary layer. Two of the flaps are instrumented by DLR Koeln and an IR thermocamera is developed by RUAG to measure the temperature of the backside of the flap and to characterize the aero-thermodynamic effects on the flap. A winglet made of ceramic material developed by CIRA is also located on the lower part. Pressure and temperature are measured at the base by a Payload developed by ALTA. A sample of intermetallic material developed by INASMET is located on the outer part of the base. ESA technical experts at ESTEC have coordinated the experiments in order to have a relevant and consistent set of experiments compliant with the vehicle resources. The preliminary design review (PDR) has been held at the end of 2006 and the critical design review (CDR) has been successfully performed in June 2007. The Payloads are now entering the production and testing phase (C/D) compatible with the flight environment conditions.