A space transportation architecture for the future

This paper summarizes the results of recent studies by Orbital to significantly reduce NASA's future launch costs and improve crew safety through the implementation of a low-risk, evolutionary space transportation architecture. These studies were performed as a part of NASA's Space Transportation Architecture Studies (STAS). The STA studies were commissioned by NASA Headquarters to advise NASA and the Executive Office of the President on the future direction of U.S space transportation. A large number of vehicles and architecture approaches were examined and evaluated. Orbital's recommended architecture includes a small, multifunctional vehicle, referred to as a Space Taxi TM, which would serve as: an emergency crew return vehicle for the International Space Station (ISS), a two-way human space transportation system, a small cargo delivery and return vehicle, and a passenger module for a future Reusable Launch Vehicle (RLV). The Space Taxi would initially be launched on a heavy-lift Evolved Expendable Launch Vehicle (EELV), currently under development by U.S. industry and the U.S. Air Force. Together with a small cargo carrier located behind the Space Taxi, this combination of vehicles would be used to meet future ISS servicing requirements. Later, a two-stage, commercially developed RLV would replace the EELV in launching the Space Taxi system at a significantly lower cost. This RLV system will provide NASA and other customers with unprecedented reductions in cost and improvements in reliability, safety, and performance.