The development of an expendable second stage for use with a reusable space shuttle booster is discussed. The configuration of a low-cost, reusable multipurpose space transportation system for the 1980 time period is presented. A system capable of economically placing payloads in earth orbit which are larger and heavier than can be carried in the shuttle orbiter cargo bay is defined. The ESS/reusable shuttle system is complementary to the space shuttle system and provides mission flexibility to permit economical expansion of the overall space program.