The Air Force Scientific Advisory Board (AF SAB) reviewed the status of aeronautical technology in the United States during the Global Reach-Global Power 1992 summer study. The AF SAB found that sufficient progress had been made in the areas of aerodynamics, materials and structures, propulsion, and fuels during the past decade to support consideration of a new generation of aircraft. Of special interest were the advancements in technology under the National Aero-Space Plane (NASP) program. The realization of unrefuled, hypersonic global range flight could have a significant impact on both commercial and military aircraft in the 21st century.This paper presents the results of a study done for the Air Force on the technical feasibility of an un-refueled, global range hypersonic aircraft. The results of the study indicate that it does not appear feasible in the foreseeable future to achieve an un-refueled hypersonic global range capability without a major technological break-through. An un-refueled range capability in excess of 12,000 n. mi. may be possible to achieve sometime during the first decade of the 21st century.