Upper stage alternatives for the shuttle era

The status and general characteristics of Space Shuttle upper stages now in use or in development, as well as new vehicle possibilities are examined. Upper stage requirements for both civil and Department of Defense missions, categorized generally into near-term (early and mid-1980's), mid-term (late 1980's to mid-1990's), and far-term (late 1990's and beyond) are discussed. Finally, the technical, schedule and cost impact of alternative ways in which these requirements could be met are examined, and a number of conclusions and recommendations are reached.