Potential directions for a second generation Space Shuttle

Abstract

This paper reports on trends and potentials for advanced rocket vehicles which may be candidates for eventual phased replacement of the Shuttle. Although such a replacement need is not foreseen until 2002 at the earliest, due to the long time to develop a new vehicle, its definition has already begun. The paper discusses the role of such a “Shuttle II” in the architecture of launch vehicles likely to exist in the post-2000 era, leading to its designation as a smaller, primarily passenger-carrying vehicle to complement large, unmanned cargo launch vehicles. While a two-stage glide-back fully reusable configuration is optimum for near-term technology, a single-stage-to-orbit reusable glide-back configuration is optimum for farther-term technology advances. For advanced technology which could be available in the mid 90s, such vehicles could orbit a payload weight equal to their own dry weight—a factor of 10 better than current launch vehicles. Major reductions in launch vehicle costs (and therefore the costs per pound of payload) are more dependent on making radical changes in ground operations than on the gross weight or type of launch vehicles.