ROGER D. LAUNIUS is chair of the Division of Space History of the Smithsonian Institution's National Air and Space Museum in Washington, D.C. He has written or edited several books on aerospace history, including Space Stations: Base Camps to the Stars (2003), To Reach the High Frontier: A History of U.S. Launch Vehicles, with Dennis R. Jenkins (2002), Imagining Space: Achievements, Predictions, Possibilities, 1950-2050, with Howard E. McCurdy (2001), and Innovation and the Development of Flight (1999).