Pietro Roncioni

Preliminary Design of Vertical Takeoff Hopper Concept of Future Launchers Preparatory Program

This paper deals with the aerodynamic and aerothermodynamic preliminary design activities for the vertical takeoff hopper concept performed in the frame of the Future Launcher Preparatory Programme of the European Space Agency. The reentry scenario with the corresponding loading environment for the proposed vehicle concept is reported and analyzed. The hypersonic aerodynamic and aerothermodynamic characteristics of the vertical takeoff hopper are investigated by means of several engineering analyses and a limited number of computational fluid dynamics simulations in order to assess the accuracy of the simplified design estimations. The results show that the difference between Eulerian computational fluid dynamics and an engineering-based design is smaller than 10% for aerodynamic coefficients, whereas a margin of about 30% has to be taken into account for what concerns the aerothermodynamic results. The final results applicable for the prosecution of the launcher design activity are that, at the condition of peak heating, the vehicle features a nose stagnation point heat flux of about 500 kW=m and an aerodynamic lift-to-drag ratio of about 1.2.

Aerodynamic and Aerothermodynamic evaluation of the VTO Hopper concept in the frame of ESA Future Launchers Preparatory Program

In the frame of the Future Launchers Preparatory Program (FLPP), carried out by the European Space Agency (ESA), the VTO Hopper - Reusable Launch Vehicle (RLV) concept is investigated. The VTO Hopper is a winged Sub Orbital Single Stage (SOSS) vehicle designed for vertical take-off. It carries an expendable upper stage, able to deliver a payload up to 8 Mg in geostationary transfer orbit (GTO). After the staging at suborbital altitude (greater than 130 km), the reusable booster will follow a ballistic arc trajectory, re-enter the Earth’s atmosphere, and then perform a downrange landing. In this paper the current aerodynamic and aero-thermodynamic activities related to the launcher design are described. The goal has been to define the preliminary aerodynamic and aerothermodynamic data-bases of the vehicle. Therefore, the aero-thermal environment that the VTO Hopper will encounter along its lifting reentry flight has been analyzed, in order to provide the necessary inputs for the Thermal Protection System (TPS) design. Different design approaches have been addressed. In fact, aerodynamic and aerothermodynamic analyses have been performed starting from engineering based methods, in order to rapidly accomplish the preliminary aerothermodynamic databases thus generating a number of possible re-entry trajectories, able to fulfill the program requirements. To perform these analyses, a 3D panel methods code, based on local inclination methods typical of hypersonics, has been employed; the heat flux distributions have been, instead, evaluated by means of improved boundary layer methods. Increasing the order of complexity, a numbers of detailed 3-D Euler CFD analyses have been performed for different flight conditions along the descent trajectory.

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.