The Army has been involved with space-based military operations for well over a half-century. During this time, space operations have changed from a realm exclusive to scientists and engineers, to highly classified activities largely unknown to the general population, to the unveiling of space-based communication, imagery, surveillance, and environment capabilities that have become a foundation for all modern warfare. Today, such support is so ingrained into daily operations that most soldiers, sailors, airmen, and marines assume it has been, and always will be, available for their use. But with such reliance comes vulnerability that potential adversaries may try to exploit. The evolution of Army space operations is well documented in many sources, thus this monograph serves not as a comprehensive history or detailed critique of the myriad accomplishments. Rather, it serves as a primer for current and future space-based operations to provide senior policymakers, decisionmakers, military leaders, and their respective staffs an overall appreciation for existing Army space capabilities and the challenges, opportunities, and risks associated with their use in joint operations.