Space Delta 2

Space Delta 2 (DEL 2) is the United States Space Force's space domain awareness and space battle management delta and is headquartered at Peterson Space Force Base, Colorado. Space Delta 2 tracks and monitors all human made objects from low Earth orbit to geosynchronous orbit and further out to deep space. It also partners with the National Oceanic and Atmospheric Administration to provide weather satellite observation for the U.S. Armed Forces. It consists of the 15th Space Surveillance, 18th Space Defense Squadron, 19th Space Defense Squadron, and 20th Space Surveillance Squadron.

Space Delta 2 was originally established on 1 February 1942 as the 21st Bombardment Group (21 BG), flying the B-25 Mitchell and B-26 Marauder in antisubmarine patrols during World War II. After the 21 BG inactivated in 1943, the 21st Fighter Group (21 FG) was activated in 1943 in Hawaii, flying the P-39 Aerocobra, P-38 Lightning, and P-51 Mustang during the Battle of Iwo Jima and escorting bombers during air raids on Japan until the 21 FS was inactivated in 1946. The 21st was reactivated again in 1952 as the 21st Fighter-Bomber Group (21 FBG) under the 21st Fighter-Bomber Wing and flying the F-86 Sabre, deploying to support NATO forces in France during the Cold War before inactivating in 1958. Although the group would be redesignated the 21st Tactical Fighter Group (21 TFG) in 1985, it would not be reactivated until 1991 as the 21st Operations Group (21 OG), when it briefly was reactivated under the 21st Wing, providing air defense for Alaska flying the F-15C and F-15E, before inactivating later that year. The 21st Operations Group was reactivated under Air Force Space Command's 21st Space Wing in 1992 and provided missile warning, space surveillance, and space control forces. On 24 July 2020, it was redesignated as Space Delta 2 and transferred from the Air Force to the Space Force on 21 October 2020.