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 manmade 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.
History
Anti-submarine patrols in the American Theater
On 1 February 1942, the 21st Bombardment Group (Medium) was activated at Bowman Field, Kentucky under the United States Army Air Forces' Air Force Combat Command, flying the North American B-25 Mitchell medium bomber. It consisted of the 8th Reconnaissance Squadron (later redesignated the 398th Bombardment Squadron), 313th Bombardment Squadron, 314th Bombardment Squadron, and 315th Bombardment Squadron. On 6 February 1942, the 21st Bombardment Group moved to Jackson Army Air Base, Mississippi, serving as an operational training group. On 11 March 1942, it was realigned under the 3rd Air Force's III Bomber Command and on 21 April 1942 moved to Columbia Army Air Base. On 2 May 1942, it was briefly reassigned from III Bomber Command to XII Bomber Command, before being regained by III Bomber Command on 8 May 1942 and moved to Key Field, Mississippi on 24 May 1942. On 24 June 1942, the 21st Bombardment Group moved to MacDill Field, Florida and converted to Martin B-26 Marauder medium bombers. While stationed at MacDill Field, the group conducted anti-submarine patrols in the Caribbean Sea, participating in the American Theater of World War II. On 10 October 1943, the 21st Bombardment Group was inactivated.
Bomber escort and fighter operations in the Pacific Theater
On 31 March 1944, the 21st Fighter Group, Two Engine, was activated on 21 April at Wheeler Field, Hawaii and assigned to the US Army Air Forces, Central Pacific Area before being realigned under Seventh Air Force's VII Fighter Command on 24 April 1944. The 21st Fighter Group consisted of the 46th Fighter Squadron, 72nd Fighter Squadron, and 531st Fighter Squadron and flew the Bell P-39Q Airacobra. Tasked with providing air defense over the Hawaiian Islands, the 21st Fighter Wing was realigned under the 7th Fighter Wing on 3 July 1944 and began upgrading to the Lockheed P-38J/L Lightning in September 1944. In October 1944, the 21st Fighter Group switched aircraft again, flying the North American P-51 Mustang and transferring to Mokuleia Field, Hawaii on 13 October 1944. On 10 November 1944, the 21st Fighter Group was realigned under the VII Fighter Command, but remained attached to the 7th Fighter Wing until 28 February 1945.