Aerodynamic behaviour of a liquid fly-back booster in transonic cruise flight

Abstract

The German future space launcher technology research program ASTRA considers for near term application a reusable first stage design which is called a winged liquid fly-back booster (LFBB). The regarded partially reusable space transportation system consists of two booster stages, which are attached to the expendable Ariane 5 core stage at an upgraded future technology level. The main area of interest of the present study is the return flight after the staging procedure which dominates the aerodynamic design of the LFBB. The goal considered in the present paper is the refinement of an existing LFBB design. With view to the trim of the vehicle former results show that there is an essential need to consider a configuration with canards. The canard deflections then may be limited to hcan=8 for subsonic flow and they are always smaller than hcan=5 for super- and hypersonic flight conditions. Main problem of the current configuration is the lack of longitudinal stability during the sub-/transonic cruise flight at M<0.7. Detailed aerodynamic parameter studies concerning the longitudinal motion point out that it is possible to adapt the current LFBB in a way that it allows a stable flight along the complete return trajectory and that it additionally enables a very robust trim behaviour.