First Wind Tunnel Data of CALLISTO - Reusable VTVL Launcher First Stage Demonstrator

In order to make access to space more affordable for both scientific and commercial activities the German Aerospace Center (DLR), the Japanese Aerospace Exploration Agency (JAXA), and the French National Centre for Space Studies (CNES) joined in a trilateral agreement to develop and demonstrate the technologies that will be needed for future reusable launch vehicles. In the joined project CALLISTO (Cooperative Action Leading to Launcher Innovation in Stage Toss back Operations) a demonstrator for a reusable vertical take-off, vertical landing rocket, acting as first stage, is developed and built. As long-term objective this project aims at paving the way to develop a rocket that can be reused, and the joint efforts of the three agencies will culminate in a demonstrator that will perform its first flights from the Kourou Space Center in French Guyana. The aerodynamic and aerothermal behaviour of the CALLISTO vehicle are investigated at DLR, including its challenging configurations with high angles of attack and subsonic up to supersonic flight regimes. To cross-check the aerodynamic data from CFD and for the enhancement of the understanding of the aerodynamic characteristics of the vehicle, experiments were performed in the Trisonic Wind Tunnel (TMK) at the DLR Department of Supersonic- and Hypersonic Flow Technologies in Cologne for Mach numbers between 0.5 and 2.5. The experiments considered the ascent and the backwards orientated decent configurations of the vehicle with folded and deployed control surfaces at several deflection angles. The angle of attack was continuously varied for all configurations. A comparison between the Aerodynamic Data Base (AEDB), generated previously using Euler and Navier-Stokes based CFD, and the experimental results showed good agreement and no significant deviations in the global coefficients were found. This paper describes the tested configurations and the experimental methods of the test campaign. An uncertainty analysis was performed for the experimental setup and the validity of the data was checked by comparison with other data from preliminary design analysis and CFD simulations. Follow-up investigations in CALLISTO project will evaluate the influence of the exhaust plume on the aerodynamics of the vehicle which is not covered by the present study