Recent NASA studies of reusable launch vehicles

Issues and studies involved in the process for developing earth to orbit (ETO) space transportation options are listed. Space transportation options must consider not only future national needs, but how such options best fit into an overall space transportation architecture. Using total architecture life cycle cost, for example, as an optimization factor may suggest different vehicle options for various payload classes and missions. NASA studies of vehicle options over the past several years have examined these relationships. Air and ground launch concepts and airbreathing systems are covered.