Revolving Door Scenario for

IN THIS ISSUE In this issue of Physics & Society, we continue our series on the risks of nuclear weapons after the Cold War. In their article Illicit Trafficking of Weapons-Usable Nuclear Material: Facts and Uncertainties, Lyudmila Zaitseva and Friedrich Steinhausler have provided us with a very detailed look at what is known about the smuggling of fissile materials. They have also provided a rather sobering estimate of how much of the smuggling may have remained undetected, as well as an analysis of the sources of uncertainties in our current knowledge. We are also very pleased to publish an analysis, by Steve Fetter, of the financial feasibility of space solar power (SSP), i.e., the collection of solar energy by photovoltaics in orbit and the transmission of that energy to Earth. Dr. Fetter’s analysis was motivated, at least in part, by a recent publication from Arthur Smith (Physics and Society, October 2003) that argued strongly in favor of SSP. On a different tack, we publish several pieces about the role of physicists in government. Two, by Stephan and by Hafemeister, recount experiences as scientific fellows in the present Federal Government. One, by Hammer, is an account of an early scientist deeply involved at the heart of American governmental affairs.