Because satellites are becoming more important to military operations on earth, and because each side is investigating space-based missile defenses, the role of anti-satellite weapons (ASATs) is growing rapidly and threatening to upset both Superpowers' defense programs. This important study carefully assesses the security consequences of the ASAT debate. The study was prepared by William J. Perry, Brent Scowcroft, Joseph S. Nye Jr. and James A. Schear. Co-published with the Aspen Strategy Group.