The Sanger-concept - A fully reusable winged launch vehicle

The present study compares winged space transportation systems with horizontal take-off (HTO) and vertical take-off (VTO), respectively. HTO vehicles were investigated at various take-off speeds and with various types of gear. While the type of acceleration till lift-off is a dominant factor for single-stage-to-orbit (SSTO) vehicles, its influence on two-stage-to-orbit (TSTO) vehicles is of lesser importance. This finding holds for lift-off velocity as well as for the type of gear. Among SSTO vehicles, a comparison of payload capability with HTO and VTO proves to be in favor of VTO in nearly all ranges. The only exceptions are at lift-off velocity Mach 0.6 in the range of lower GLOW and in a certain range for the sled-propelled vehicles. Concerning TSTO vehicles no essential differences between VTO and HTO can be discerned. Finally, different launch vehicles (SSTO and SANGER) with 20 Mg payload were compared, resulting in a definite advantage of the TSTO-SANGER solution in terms of performance and lower developmental risks.