Book excerpt: Space Superiority is a core task for the USAF, critically enabling US combat operations. As the US becomes more reliant on space-based resources to ensure military and economic success, the need to protect them will increase. A robust space threat warning capability--the ability to detect, assess and respond to hostile actions against space assets--is the foundation for this protection Senior leaders in the US government have stated the US must avoid a space Pearl Harbor. This concern is due to the idea that a decrease in the perceived threat to space assets after the demise of the Soviet Union coupled with a competition for space resources has resulted in a corresponding erosion of US space threat warning and attack assessment capabilities. This paper describes the development and gradual erosion of US space threat warning capabilities, emerging threats, and discusses the implications to national security should the US fail to field a robust space threat warning and attack verification capability. The paper concludes with recommendation to establish a focal point for space defense, institute end-to-end testing of the threat warning process, and to update space threat warning guidance to ensure space is not location of the next "Pearl Harbor."