As part of a two-year effort to develop an expansive construct of air and space power in the early twenty-first century that capitalizes on forthcoming air and space technologies and concepts of operation and is effective against adversaries with diverse economies, cultures, political institutions, and military capabilities, the research team investigated the possibility that future adversaries might be able to mount effective missile attacks on U.S. Air Force (USAF) main operating bases in critical regions. This report does not assess the relative vulnerabilites of various force elements and facilities; instead, it aids the USAF in addressing a potential vulnerability of its in-theater bases: highly accurate attacks against USAF aircraft on parking ramps at such bases made possible by the proliferation of Global Positioning System (GPS) guidance and submunition warhead technologies.