The 21st Space Wing headquarters is located at Peterson Air Force Base. The 21st SW is the Air Force's most geographically-dispersed wing, and the fifth largest wing in the Air Force by number of units. It literally covers the world with its operations. As Air Force Space Command's largest, most weapon-system diverse, and geographically separated operations group, it commands and controls missile warning and space control units around the globe. The group provides real-time missile warning, attack assessment, and space control to the President, Secretary of Defense, JCS, combatant commands and foreign allies. Through its commander, the group develops future combat counterspace capabilities in support of theater campaigns.