The North American Aerospace Defense Command (NORAD) is a bi-national United States and Canadian organization charged with the missions of aerospace warning and aerospace control for North America. Aerospace warning includes the monitoring of man-made objects in space and the detection, validation, and warning of attack against North America whether by aircraft, missiles, or space vehicles, through mutual support arrangements with other commands. Aerospace control includes ensuring air sovereignty and air defense of the airspace of Canada and the United States. Headquarters for NORAD and the NORAD/United States Northern Command (USNORTHCOM) center are located at Peterson Air Force Base in El Paso County, near Colorado Springs, Colorado. The nearby Cheyenne Mountain Complex has the Alternate Command Center.