The sixth and newest military service branch, the United States Space Force (USSF) was created in 2019 under the Department of the Air Force . It consists of about 4,200 enlisted service members and about 4,300 officers, all known as Guardians. The Space Force is tasked with protecting U.S. and allied interests in space, most notably to protect and defend the massive U.S. satellite fleet. Its domains include the Global Positioning System ( GPS ), cyber operations, improving defense technology