The 21st Space Wing is a unit of the Air Force Space Command based at Peterson Air Force Base, Colorado. The unit is tasked with the operation of early missile warning and space object detection equipment around the world in support of NORAD and USSTRATCOM through a network of command and control units and ground based sensors operated by geographically separated units around the world.
The Wing’s services include more than 9,000 government and contractor personnel detect, track and catalog more than 14,000 catalogued man-made objects in space, from those in near-Earth orbit to objects up to 22,300 miles above the earth's surface and explores counterspace warfighting technologies in the field.
Ballistic missile warning allows the US to monitor at least 20 nations currently have nuclear, biological or chemical weapons, and the technology to deliver them over long distances, including some with the ability to launch intercontinental ballistic missiles at the United States.
The 21st Operations Group manages all operation units in the 21st Space Wing.
The Wing's ground-based radars are: a sea-launched ballistic missile or SLBM, the PAVE PAWS warning system; a Ballistic Missile Early Warning System, or BMEWS; and a Perimeter Attack Radar Characterization System, or PARCS.
SLBM warning units are the 6th SWS, Cape Cod AFS, Mass., and the 7th SWS, Beale AFB, Calif. Their mission is mainly to watch America's coasts for incoming sea-launched or intercontinental ballistic missiles, and warn NORAD and NORTHCOM.
The wing's two BMEWS radar units are the 12th Space Warning Squadron, Thule AB, and the 13th Space Warning Squadron at Clear AFS. The 21st SW also has a detachment at RAF Fylingdales, U.K., to coordinate cooperative missile warning and space surveillance with RAF counterparts.
The wing's PARCS unit is the 10th Space Warning Squadron, Cavalier AFS, N.D.
The 20th Space Control Squadron, Eglin AFB, Fla., provides dedicated active radar space surveillance. In addition, other collateral and contributing missile warning and research radars are used to support the surveillance mission.
Besides the three major commands, the Wing directs and supports Cheyenne Mountain Air Force Station (CMAFS); Thule Air Base (TABG), Greenland; Clear AFS (CAFS), Alaska, and Cape Cod AFS (CCAFS), Mass. The 21st also provides community support to 302d Airlift Wing (CANG), the 50th Space Wing, Schriever AFB, Colo and to its neighbors in the Colorado Springs area.

United States Air Force
Constituted as 21st Bombardment Group (Medium) on 13 Jan 1942. Activated on 1 Feb 1942. Began training with B-25's; later converted to B-26's. Served as an operational training unit in Third AF; also flew some antisubmarine patrols over the Gulf of Mexico. Disbanded on 10 Oct 1943.
Constituted as 21st Fighter Group on 31 Mar 1944. Activated in Hawaii on 21 Apr 1944.
Assigned to Seventh Air Force and served as part of the defense force for the Hawaiian Islands. Equipped first with P-39 Airacobras, later with P-38 Lightnings, and lastly (Jan 1945) with P-51 Mustang aircraft.
Reassigned to Iwo Jima, Feb-Mar 1945. Sustained some casualties when Japanese troops attacked the group's camp on the night of 26/27 Mar 1945, but flew first combat mission the following day, bombing and strafing airfields on Haha Jima. Flew its first mission to Japan on 7 Apr, being awarded a Distinguished Unit Citation (DUC) for escorting B-29's that struck the heavily-defended Nakajima aircraft factory near Tokyo. Operations from Iwo Jima included attacking airfields that the enemy was using to launch suicide planes against the Allied forces on Okinawa; striking enemy barracks, airfields, and shipping in the Bonins and Japan; and escorting B-29 Superfortresss that bombed Japanese cities.
During the summer of 1945, the 21st Fighter Group (along with the 15th from the VII Fighter Command) was reassigned to the Twentieth Air Force, 301st Fighter Wing. The group continued its fighter sweeps against Japanese airfields and other targets, in addition to flying long-range B-29 Superfortress escort missions to Japanese cities, until the end of the war.
With the end of hostilities, the group trained, participated in aerial reviews, and served as a part of the defense force for Iwo Jima, Saipan, and Guam after the war. Re-equipped with P-47 Thunderbolts during the summer of 1946.
Inactivated on Guam on 10 Oct 1946.
At George, the wing established and maintained tactical proficiency and provided air defense augmentation. In December 1954, the wing was assigned to NATO and was reassigned to Chambley-Bussieres Air Base, France.
United States Air Forces In Europe
The 21 FBW consisted of three squadrons, the 72d, 416th and 531st Fighter-Bomber Squadrons, equipped with the F-86F Sabre. Upon their arrival, the facilities at Chambley were not ready for aircraft use, and the squadrons had to deploy elsewhere. The 72d deployed to Chateauroux AB, while the 416th and 531st operated out of Toul-Rosieres AB.
After many construction delays, the wing combined its fighter squadrons at Chambley on 15 April 1955. The squadrons carried out close air support training missions with the Army, then took first place at the United States Air Forces in Europe (USAFE) "Gunnery Meet" at Wheelus Air Base, Libya.
The 21 FBW participated in the Atomic Warfare exercise Carte Blanche, and went on to take an overall second place in the Nellis AFB, Nevada Gunnery Meet in 1956. Moreover, they won the USAFE Award for Tactical Proficiency for the January-June period of 1957.
In 1957, the French Government decreed that all nuclear weapons and delivery aircraft had to be removed from French soil by July 1958. As a result, the F-86's of the 21st Fighter-Bomber Wing had to be removed from France.
During October 1957 it was announced that the 21 FBW would be inactivated on 8 February 1958, and that its assets would be dispersed among existing USAFE units. With the departure of the wing, Chambley-Bussieres AB was placed in reserve status. The 21st Fighter Wing was reactivated at Misawa AB, Japan a few months later on 1 July 1958, inheriting the lineage of the 21st FBW.
Participated in numerous actual and simulated tactical air operations and provided air defense augmentation in Japan and Korea, Jul 1958-Jun 1960.
Alaska
In 1966, assumed air defense responsibility for Alaska and contiguous areas in support of North American Air Defense Command (NORAD) and Aerospace Defense Command (ADCOM) through the Alaskan NORAD Region and ADCOM Region. Provided support for multi-service special operations in Arctic regions and participated in numerous search and rescue efforts, 1966-1991. Maintained air defense and alert forces at forward operating bases in Galena and King Salmon, AK, 1977-1991. In 1978-1979 lent humanitarian support and assistance to Vietnamese refugees relocating to Canada.
The 1980s witnessed a period of growth and modernization of Elmendorf AFB. During 1982, the 21st TFW converted from F-4s to F-15s.
In 1991, the 21st Tactical Fighter Wing was reorganized as an objective wing and all the major tenant units on Elmendorf were placed under it. The 21st Wing was de-activated and the 3d Wing was reassigned from Clark Air Base to Elmendorf Air Force Base on 19 December 1991. This was in keeping Air Force's polices of retaining the oldest and most illustrious units during a period of major force reductions.