The Space Policy of the United States establishes human expansion into the solar system as a national goal. The Office of Exploration (OEXP) was established in 1987 to study in greater detail the ideas which were identified in the efforts of the National Commission on Space and subsequently the Sally Ride report, “Leadership …”. Specifically, the goals of OEXP were to: (1) identify viable alternatives for an early 1990s national decision, (2) understand available options and opportunities, and (3) understand and define near-term investments.During the course of this past two years, exploration strategies have been developed. A case study methodology has been employed to greater understand the range of parameters which influence the pathway and destination, i.e., the Moon or Mars. Near-term constraints which have been identified are the Earth-to-orbit (ETO) transportation, life sciences research, and robotic precursors. The critical technologies identified thus far are cryo propellant management, aerobraking, advanced propulsion, nuclear power, a life support system, automation and robotics, extraterrestrial construction and operations.This paper covers some of these topics in greater detail. Current case studies are outlined and the significant results of the present efforts discussed.