From model rockets to spacewalks: an astronaut physician's journey and the science of the United States' space program.

From simple childhood dreams to their fulfillment, this presentation chronicles the author's life journey from young model rocketteer through his medical training and eventual career as a NASA astronaut. Over the course of four Space Shuttle flights and a cumulative 6 weeks in space, including 20 hours of Extravehicular Activity (EVA, or spacewalking), this article describes a wide range of activities and scientific payloads that are representative of the unique and valuable science that can be accomplished in the microgravity of space. NASA's efforts to develop inspection and repair capabilities in the aftermath of the Columbia tragedy are also covered, as are the nation's plans for returning to the Moon and continuing on to Mars as part of the Vision for Space Exploration (VSE).