Giuseppe C. Rufolo

PRORA USV1: The First Italian Experimental Vehicle to the Aerospace Plane

This paper deals with the system design of the USV1, the first Space experimental vehicle funded by the Italian National Aerospace Research Program (PRORA). The Unmanned Space Vehicle 1 (USV1) is a multi-mission, re-usable vehicle under development in CIRA, the Italian Aerospace Research Centre. The first USV1 mission is scheduled for the end of 2005 and is aimed at experimenting the transonic flight of a re-entry vehicle. In addition, being a multi-mission flying laboratory, USV1 will perform three flights, each one of them simulating the final portion of a typical re-entry trajectory. USV1 is basically composed by a Flying Test Bed (FTB1) and a Carrier based on a stratospheric balloon. The FTB1 is a slender, not-propelled, winged vehicle able to perform experiments on Structure and Aeroelasticity behaviour identification, Autonomous Guidance Navigation and Control, and Thermo-Aerodynamics. During the missions the balloon will carry the FTB1 up to the desired altitude (25 Km for the first mission) and then, after having established a cruise horizontal trajectory, will release it from the gondola. At this moment FTB1 will start its proper flight following the designed trajectory. In the frame of a step by step approach the FTB1 will reach during each subsequent mission an increasing number of Mach, starting from Mach 1 during the first mission up to Mach 2 during the fourth flight. At the maximum velocity it will perform the experiments and by means of a pull up manoeuvre it will decelerate in order to enter in the safe parachute opening regime. The final recovery will be performed from the sea. After a brief description of the missions the paper will present the system architecture and the adopted solution able to match the mission and experiment requirements for all the foreseen missions. At the time of the conference the FTB1 shall be performing the integration and test phase and all the subsystem shall be delivered to CIRA.

European Experimental Reentry Testbed Winglet: From In-Flight Characterization to SCIROCCO Test

Thiswork is dedicated to the aerothermodynamic characterization, both inflight and atwind-tunnel conditions, of the ultrahigh temperature ceramic winglet that will embark on the European Experimental Reentry Testbed of the European Space Agency. The experimental test has been executed in the Centro Italiano Ricerche Aerospaziali SCIROCCO plasma wind tunnel on a winglet qualification model. The aim of the test was to reproduce the total thermal load,which thewingletwill be subjected to during the reentry trajectory, allowing preflight qualification and verification of materials and sensing equipment. Detailed three-dimensional computations in plasma-wind-tunnel conditions have allowed the verification of the test requirements and provided information about the physical phenomena that can cause dangerous local overpressures and overheatings on the capsule thermal protection system.The actual test condition has been rebuilt after the test bymeans of three-dimensional simulations; particular attention has been paid in modeling surface catalysis and emissivity. Finally, the aerothermodynamic code has been coupled with a thermal code to account for material thermal conduction. Numerical results have been compared in terms of pressure and temperature with experimental measurements showing good agreement.

Aerothermodynamic Analysis of the EXPERT Winglet: from the in-flight environment characterization to the rebuilding of the Scirocco Plasma Wind Tunnel test

This paper is dedicated to the aerothermodynamic characterization, both in flight and in wind tunnel conditions, of the Ultra High Temperature Ceramic winglet that will be embarked on the ESA re-entry demonstrator, EXPERT (Payload 15). The experimental test has been executed in the CIRA “Scirocco” Plasma Wind Tunnel, on a winglet qualification model. Aim of the test has been to reproduce, in a relevant plasma environment, the total thermal load which the winglet will be subjected to during the EXPERT re-entry trajectory, in the point of maximum heat flux (M=13.41, altitude 33.8 km), so allowing pre-flight qualification and verification of materials and sensing equipment. Conservative flight heat fluxes on the winglet and on the capsule region surrounding it have been computed by means of three dimensional numerical simulations on the actual EXPERT geometry both in laminar and in transitional flight conditions. Then, detailed three-dimensional computations in Plasma Wind Tunnel conditions have allowed the verification of the test requirements and provided information about the physical phenomena that can cause dangerous local overpressures and overheatings on the Thermal Protection System (i.e. shock wave/boundary layer interaction, blunt/fin interaction, etc.). Run duration has been established with the aim at realizing on the winglet the same total thermal load experienced in flight. The actual test condition has been rebuilt after the test by means of three-dimensional fluid dynamics simulations; particular attention has been paid in modeling surface catalysis and emissivity. Finally, the fluid dynamics code has been coupled with a thermal code in order to account for material thermal conduction. Numerical results have been compared in terms of pressure and temperature with experimental measurements showing good agreement.

Post Flight Aerodynamic Analysis of the Experimental Vehicle PRORA USV 1

Some results of the post flight analysis of the aerodynamic experiment carried out within the frame of USV project, the first Space experimental vehicle funded by the Italian National Aerospace Research Program (PRORA), are shown in this paper. The first mission DTFT (Dropped Transonic Flight Test) of the Unmanned Space Vehicle 1 (USV1) developed at CIRA, was performed at the end of February 2007, and it was aimed at experimenting the transonic flight of a re-entry vehicle. USV is basically composed by a Flying Test Bed (FTB1) and a Carrier based on a stratospheric balloon. The FTB1 is a slender, not-propelled, winged vehicle able to perform experiments on Aerodynamics, Structure and Materials, Autonomous Guidance Navigation and Control. The logical path of the USV aerodynamic experiment entails the comparison between Pre-Flight prediction and In-Flight measurements. Such comparison will be actuated by means of the acquisition during the USV flight both of the global aerodynamic coefficients (inertial measurements) and local quantities (pressure measurements). During the flight, static pressure measurements over the vehicle surface are gathered. 304 probe have been located in the most interesting regions of the vehicle. Some selected flight conditions occurred during the DTFT mission of the FTB1 vehicle have been numerically rebuilt, the attention being focused to the surface pressure distributions to be compared with in-flight pressure measurements. After the execution of these CFD simulations, results have been critically analyzed and compared to flight data. All the information deriving from the Aerodynamic Flight Experiment will be finally used to improve the existing Aerodynamic Prediction Model.

European Space Agency intermediate experimental vehicle: Development of an independent aerothermodynamic database tool

In the frame of the European Space Agency (ESA) Intermediate eXperimental Vehicle (IXV) project, ESA is coordinating a series of technical assistance activities aimed at verifying and supporting the IXV industrial design and development process. The technical assistance is operated by the Italian Space Agency, by means of the technical support of the Italian Aerospace Research Centre. One of the purposes of the activity is to develop an independent capability for the assessment and verification of the industrial results with respect to the aerothermodynamic characterization of the IXV vehicle. To this aim, CIRA have developed an independent aerothermodynamic database, intended as a tool generating in output the time histories of local quantities for each point of the IXV vehicle surface and for each trajectory, together with an uncertainties model. The whole procedure followed for the definition of the numerical tool and the main results achieved will be presented in this article.

Rebuilding and Analysis of a SCIROCCO PWT Test on a Large TPS Demonstrator

In September 2007, a Plasma Wind Tunnel (PWT) Test was performed in the CIRA SCIROCCO facility on the FLPP Snecma Propulsion Solide (SPS) Thermal Protection System (TPS) demonstrator (Barreteau et al., 2008). Aim of the test was to verify, in a space qualifying environment, the behaviour of a large assembly constituted by Ceramic Matrix Composite (CMC) shingles, one curved and two flat panels, the same elements which will be part of the next ESA Intermediate Experimental Vehicle (IXV) thermal protection system. The focus of this chapter is the description of the CFD activities carried out in order to realize and support the plasma wind tunnel test, both in the phase of test definition and for the post test analysis. During the pre-test CFD activity the test condition, previously defined by a simplified two dimensional methodology (Rufolo et al., 2008), has been verified by means of three dimensional simulations, and the final PWT test condition has been defined. Then, the posttest CFD rebuilding activity has allowed the analysis of results and the comparison with experimental measurements. In addition, an assessment of the uncertainty level related to the satisfaction of the test requirements, in terms of heat flux and pressure to be realized over the test article, has been provided by analyzing the sources of error linked to both design and testing phases.