| Mission Delta 2 | |
|---|---|
Mission Delta 2 emblem | |
| Founded | 1 February 1942; 83 years ago (1942-02-01) as 21st Bombardment Group[1] 24 July 2020; 5 years ago (2020-07-24) as Space Delta 2 |
| Country | |
| Branch | |
| Type | Delta |
| Role | Space domain awareness |
| Size | 380 personnel[2] |
| Part of | |
| Headquarters | Peterson Space Force Base,Colorado, U.S. |
| Nickname | Sentinels[3] |
| Engagements | Antisubmarine, American Theater Air Offensive, Japan Globalwar on terrorism[1] |
| Decorations | Distinguished Unit Citation Air Force Outstanding Unit Award[1] |
| Website | www |
| Commanders | |
| Commander | Col Barry A. Croker |
| Deputy Commander | Lt Col Scott D. Munn[4] |
| Senior Enlisted Leader | CMSgt Leomel I. Abueg[5] |
| Insignia | |
| Guidon | |
Mission Delta 2 (MD2) is theUnited States Space Force'sspace domain awarenessdelta, headquartered atPeterson Space Force Base, Colorado. Mission Delta 2 tracks and monitors all human made objects fromlow Earth orbit togeosynchronous orbit and further out todeep space. It also partners with theNational Oceanic and Atmospheric Administration to provide weather satellite observation for the U.S. Armed Forces. It consists of the15th Space Surveillance Squadron,18th Space Defense Squadron,19th Space Defense Squadron, and20th Space Surveillance Squadron.[6][7]
Mission Delta 2 was originally established on 1 February 1942 as the21st Bombardment Group (21 BG), flying the B-25 Mitchell and B-26 Marauder in antisubmarine patrols duringWorld War II. After the 21 BG inactivated in 1943, the21st Fighter Group (21 FG) was activated in 1943 in Hawaii, flying the P-39 Airacobra, P-38 Lightning, and P-51 Mustang during theBattle 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 the21st 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 theCold War before inactivating in 1958. Although the group would be redesignated the21st Tactical Fighter Group (21 TFG) in 1985, it would not be reactivated until 1991 as the21st 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 underAir Force Space Command's21st 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.[1] On 31 October 2024 it was redesignated Mission Delta 2 and gained sustainment responsibilities, along with organic cyber defense and intelligence forces.[8]

On 1 February 1942, the 21st Bombardment Group (Medium) was activated atBowman Field, Kentucky under theUnited States Army Air Forces'Air Force Combat Command, flying theNorth American B-25 Mitchellmedium bomber. It consisted of the8th Reconnaissance Squadron (later redesignated the 398th Bombardment Squadron),313th Bombardment Squadron,314th Bombardment Squadron, and315th Bombardment Squadron. On 6 February 1942, the 21st Bombardment Group moved toJackson Army Air Base, Mississippi, serving as an operational training group. On 11 March 1942, it was realigned under the3rd Air Force'sIII Bomber Command and on 21 April 1942 moved toColumbia Army Air Base. On 2 May 1942, it was briefly reassigned from III Bomber Command toXII Bomber Command, before being regained by III Bomber Command on 8 May 1942 and moved toKey Field, Mississippi on 24 May 1942. On 24 June 1942, the 21st Bombardment Group moved toMacDill Field, Florida and converted toMartin B-26 Marauder medium bombers. While stationed at MacDill Field, the group conductedanti-submarine patrols in the Caribbean Sea, participating in theAmerican Theater ofWorld War II. On 10 October 1943, the 21st Bombardment Group was inactivated.[9][1]

On 31 March 1944, the 21st Fighter Group, Two Engine, was activated on 21 April atWheeler Field, Hawaii and assigned to the US Army Air Forces, Central Pacific Area before being realigned underSeventh Air Force'sVII Fighter Command on 24 April 1944. The 21st Fighter Group consisted of the46th Fighter Squadron,72nd Fighter Squadron, and531st Fighter Squadron and flew theBell P-39Q Airacobra. Tasked with providingair defense over the Hawaiian Islands, the 21st Fighter Wing was realigned under the7th Fighter Wing on 3 July 1944 and began upgrading to theLockheed P-38J/L Lightning in September 1944. In October 1944, the 21st Fighter Group switched aircraft again, flying theNorth American P-51 Mustang and transferring toMokuleia 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.[9]

In February 1945, the 21st Fighter Group was directly resubordinated under the VII Fighter Command and transported by ships to Iwo Jima, arriving atCentral Field on 25 March 1945. On the Morning of 26 February 1945, the elements of the 21st Fighter Group was attacked byImperial Japanese Army soldiers on the ground. Fighting alongside a contingent ofU.S. Marines, the airmen killed 250 Japanese soldiers in tent-to-tent fighting, with fourteen 21st Fighter Group airmen killed and 50, including the group commander, ColonelKenneth R. Powell, were wounded. Following the engagement on the ground, the 21st Fighter Group providedclose air support for the remainder of theBattle of Iwo Jima.[9]
Following the island's capture, the 21st Fighter Group began conducting long-rangebomber escort missions, with the first occurring on 7 April 1945, where P-51 Mustangs from the group escorted B-29 Superfortress heavy bombers striking theNakajima Aircraft Company in Tokyo. This mission was the first time bombers over Japan were accompanied by escort fighters and was the longest over-water fighter escort mission to that point during World War II. On 16 July 1945, the group transferred to Iwo Jima'sSouth Field and flew its last combat mission over Japan on 14 August 1945. For its raid over Nakajima Aircraft Company, the 21st Fighter Group was awarded theDistinguished Unit Citation. After the end of World War II, the 21st Fighter Group transferred toIsely Field, Saipan on 4 December 1945 and then toNorthwest Field, Guam on 17 April 1946. The 21st Fighter Group was inactivated on 10 October 1946.[9]

On 1 January 1953, the 21st was reactivated as the 21st Fighter-Bomber Group atGeorge Air Force Base, California under the21st Fighter-Bomber Wing. Following the end of World War II, thewing replaced thegroup as the primary unit of organization within the Air Force. Initially organized underTactical Air Command'sNinth Air Force, the 21st Fighter-Bomber Group consisted of its World War II72nd Fighter-Bomber Squadron and531st Fighter-Bomber Squadron, adding the416th Fighter-Bomber Squadron. Initially flying theF-51 Mustang fighter, within six months of activation, the 21st Fighter-Bomber Group had transitioned to theNorth American F-86F Sabre, a first-generation jet fighter. In September and October 1953, the 21st Fighter-Bomber Group participated in a special arctic warfare program atEielson Air Force Base, Alaska. Following the completion of this exercise, it sent six F-86s to participate in Project Willtour, which consisted of an 11,000 mile tour of twelve Central, Caribbean, and South American countries. In April and May 1954, it participated in Operation Boxkite atNorth Field, South Carolina, testing the ability for a tactical wing to deploy to a forward location and sustain thirty days of combat operations.[9]
Following the completion of these exercises, on 22 June 1954, theSecretary of the Air Force announced that the 21st Fighter-Bomber Wing, including the 21st Fighter-Bomber Group, would be deployed toChambley Air Base, France, underTwelfth Air Force and theNorth Atlantic Treaty Organization to defend against theWarsaw Pact andSoviet Union. While the 21st Fighter-Bomber Wing's personnel moved in four tranches across air, land, and sea transport, the 21st Fighter-Bomber Group's F-86s flew directly, stopping in Labrador, Greenland, Iceland, and Scotland. The 21st Fighter-Bomber Group officially was stationed at Chambley Air Base on 12 December 1954, however the airfield could not handle the jet fighters until it was upgraded by Air Force engineers in June 1956. The flying elements of the group operated in the interim out of a variety of airfields in the French countryside.[9]
One of the most notable pilots in the 21st Fighter-Bomber Group was then-First LieutenantMichael Collins, who would later become aNASA astronaut, flying theGemini 10 andApollo 11 missions, before retiring from the Air Force as a major general.[9]
The 21st Fighter-Bomber Group conducted close air support training withUnited States Army Europe land forces and took first place at theUnited States Air Forces in Europe's gunnery meet atWheelus Field, Libya. In 1955, the 21st Fighter-Bomber Group participated NATO'sCarte Blanche atomic warfare exercise and took second place atNellis Air Force Base's gunnery exercise in 1956. The unit also won the United States Air Forces in Europe award for tactical proficiency in 1957. On 8 February 1958, the 21st Fighter-Bomber Group and 21st Fighter-Bomber Wing were inactivated.[9]
While the 21st Wing would continue, Air Force policy on operations groups resulted in the 21st Fighter-Bomber Group remaining inactive for the following decades. In 1985, it was redesignated as the 21st Tactical Fighter Group, but not activated until 25 September 1991 as the 21st Operations Group under the21st Wing atElmendorf Air Force Base, Alaska. It briefly consisted of the21st Operations Support Squadron,43rd Fighter Squadron,54th Fighter Squadron, and90th Fighter Squadron underAlaskan Air Command and supportingNorth American Aerospace Defense Command. The 43rd Fighter Squadron and 54th Fighter Squadron flew theMcDonnell Douglas F-15C Eagle, while the 90th Fighter Squadron flew theMcDonnell Douglas F-15E Strike Eagle. Following the 21st Operations Group's activation, the Air Force implemented a program that directed that each base would have one wing and one commander. The 21st Wing and3rd Wing shared Elmendorf Air Force Base, resulting in the 21st Wing, and 21st Operations Group's inactivation on 19 December 1991.[9]

On 15 May 1992, the 21st Operations Group was reactivated alongside the21st Space Wing atPeterson Air Force Base underAir Force Space Command, with the 21st Operations Group specifically absorbing the responsibilities of the former1st Space Wing. The 21st Operations Group's primary mission wasmissile warning. It operated theDefense Support Program missile warning constellation, which was flown by the2nd Space Warning Squadron atBuckley Air National Guard Base and the5th Space Warning Squadron atWoomera Air Station, Australia, while the4th Space Warning Squadron operated the Mobile Ground Station fromHolloman Air Force Base, before transferring the mission to theAir National Guard's137th Space Warning Squadron in 1997. The11th Space Warning Squadron was activated in 1994 atFalcon Air Force Base to operate the Attack and Launch Early Reporting to Theater (ALERT) missile warning system.[9]
The 21st Operations Group also inherited threeBallistic Missile Early Warning System (BMEWS) radars, operated by the13th Space Warning Squadron atClear Air Force Station, Alaska,12th Space Warning Squadron atThule Air Base, Greenland, and aRoyal Air Force operated radar atRAF Fylingdales. As the BMEWS radars had been in operation since the 1960s, the sites were in the process of being upgraded to theSolid State Phased Array Radar System (SSPAR), with Thule Air Base's being upgraded in 1987, RAF Fylingdales' in 1992, and Clear Air Force Station's in 2001. The 21st Operations Group also inherited thePAVE PAWS radars operated by the6th Space Warning Squadron atCape Cod Air Force Station,7th Space Warning Squadron atBeale Air Force Base,8th Space Warning Squadron atEldorado Air Force Station, and9th Space Warning Squadron atRobins Air Force Base. The last ground-based missile warning radar operated by the 21st Operations Group was theAN/FPQ-16 PARCS atCavalier Air Force Station and operated by the10th Space Warning Squadron. Following the end of the Cold War and the implementation of budget cuts, the radars and squadrons as Eldorado Air Force Station and Robins Air Force Base were inactivated.[9]

The 21st Operations Group also operated a network ofspace surveillance radars across the Earth. TheAN/FPS-79 was operated by the19th Space Surveillance Squadron atPirinçlik Air Base, Turkey. The radar and its predecessor had been conducting operations since 1955 and monitored space and missile launches out of theSoviet Union and Russia, including the launch ofSputnik,Vostok, and events related toOperation Desert Storm until it was inactivated in 1999. The 21st Operations Group also gained the20th Space Surveillance Squadron, which had operated theAN/FPS-85 atEglin Air Force Base since 1988. Detachments of the18th Space Surveillance Squadron operated theGround-based Electro-Optical Deep Space Surveillance System (GEODSS), with Detachment 1 operating atSocorro, New Mexico, Detachment 2 atDiego Garcia, and Detachment 3 at theMaui Space Surveillance Complex, replacing the older network ofBaker-Nunn cameras. Detachment 4 operated the Transportable Optical System (TOS) atMorón Air Base starting in September 1998, and was renamed the Moron Optical Surveillance System (MOSS) in 1999. In November 2005, Morón Air Base would receive the El Raven telescope and in June 2006 it would gain the RO4 high-volume superior resolution camera. The 21st Operations Group also operated two passive radars, with the Deep Space Tracking System antennas operated by the3rd Space Surveillance Squadron atMisawa Air Base, Japan and5th Space Surveillance Squadron atRAF Feltwell. The Low Altitude Space Surveillance System was operated by the4th Space Surveillance Squadron atLackland Air Force Base, Detachment 1 atOsan Air Base, Korea, the1st Space Surveillance Squadron atGriffiss Air Force Base, and the17th Space Surveillance Squadron atRAF Edzell. In 1995, the 1st Space Surveillance Squadron inactivated, and in 1996 the 17th Space Surveillance Squadron followed suit, with Detachment 1 inactivating in 1997. The remaining passive radar systems were shut down, with the 5th Space Surveillance Squadron inactivating in January 2002 and the 3rd Space Surveillance Squadron following in February 2002.[9]

The 21st Operations Group maintained a set of command and control squadrons to coordinate its primary missions. The1st Command and Control Squadron, based atCheyenne Mountain Air Force Station, was responsible for tasking theUnited States Space Surveillance Network and maintained thespace catalog. The2nd Command and Control Squadron operated out ofSchriever Air Force Base and controlled the passive space surveillance network. The3rd Command and Control Squadron was based atOffutt Air Force Base and served as the alternateMissile Warning Center. In 1998, the 2nd Command and Control Squadron would transfer to the14th Air Force as passive space surveillance units began inactivating, while new capabilities at theMissile Warning Center rendered the 3rd Command and Control Squadron redundant, inactivating in 1999. The 1st Command and Control Squadron was realigned under the614th Air and Space Operations Center in June 2008. In 1996, the821st Space Group was activated atBuckley Air National Guard Base under the 21st Space Wing, gaining theDefense Support Program and its squadrons from the 21st Operations Group. On 1 October 1994, the 21st Crew Training Squadron inactivated and in 1997 the84th Airlift Flight, which operated theLearjet C-21 forAir Force Space Command, was transferred toAir Mobility Command.[9]

Following increased proliferation of debris and international actors in space, the 21st Operations Group began to transition from space surveillance to space control, or counterspace, renaming its squadrons. Space control squadrons were intended to guard against hostile action while also preventing collision with space debris. The first space control squadron, the76th Space Operations Squadron was activated at Peterson Air Force Base in 2000 and renamed the 76th Space Control Squadron in January 2001, receiving initial operational capability on the Counter Communications System in September 2004. On 1 March 2003, all space surveillance squadrons were redesignated as space control squadrons. In July 2005, the4th Space Control Squadron atHolloman Air Force Base began to move into the space control mission in July 2005, activating its first counter communications system in April 2006, transferring to Peterson Air Force Base in July 2014 and absorbing the 76th Space Control Squadron in February 2015. In May 2007, the16th Space Control Squadron was activated at Peterson Air Force Base as a defensive space control squadron. As part of an Air Force manpower saving program, the18th Space Control Squadron was inactivated in April 2004, with its Detachments 1-4 directly realigned under the 21st Operations Group. In August 2004, the20th Space Control Squadron activated Detachment 1 atNaval Support Activity Dahlgren to operate theAir Force Space Surveillance System (formerly the Navy Space Surveillance System) and the Alternate Space Control Center. Detachment 1, 20th Space Control Squadron was inactivated in April 2010, followed by the inactivation of Detachment 4, 21st Operations Group atMorón Air Base in March 2013. In April 2013, the13th Space Warning Squadron gained oversight of theCobra Dane radar atEareckson Air Station, Alaska. On 20 April 2016, the GEODSS detachments transitioned from the 21st Operations Group to the 20th Space Control Squadron and the 18th Space Control Squadron was reactivated on 22 July 2016 atVandenberg Air Force Base.[9]
In 2019, the 721st Operations Group was activated and gained the 4th Space Control Squadron and 16th Space Control Squadron.[10]
Following the establishment of theUnited States Space Force, the 21st Space Wing and 21st Operations Group remained units of the U.S. Air Force assigned toUnited States Space Force. On 24 July 2020, the Space Force reorganized its wings and groups into deltas, inactivating the 21st Space Wing and redesignated the 21st Operations Group as Space Delta 2. Space Delta 2 transferred its space warning squadrons toSpace Delta 4, retaining its space surveillance awareness and space defense squadrons. On 21 October 2020, with the redesignation of United States Space Force as Space Operations Command, Space Delta 2 transferred from a unit of the United States Air Force to the United States Space Force.[1] On 31 October 2024 it was redesignated Mission Delta 2 and gained sustainment responsibilities, along with organic cyber defense and intelligence forces.[11]
The 21st Operations Group emblem was shared with the21st Space Wing and its other groups. The blue represents the vast blue sky-the 21st's area of operations. The upraised sword indicates the strength and readiness of the wing to perform its mission, whether in peace or war. The lightning is symbolic of the heavens beyond, the stormy power and protective Lord. The Air Force blue, red, and yellow signifies the three fighter squadrons of the 21st Fighter–Bomber Wing. The emblem was approved on 23 July 1957.[9]
The motto "Strength and Preparedness" is derived from the original motto of the 21st Fighter-bomber Wing "Fortitudo et Preparatio."[9]
| No. | Commander | Term | Ref | |||
|---|---|---|---|---|---|---|
| Portrait | Name | Took office | Left office | Duration | ||
| 1 | Cantore, Matthew S.Colonel Matthew Cantore | 24 July 2020 | 14 June 2021 | 325 days | [15] | |
| 2 | Brock, Marc A.Colonel Marc A. Brock | 14 June 2021 | 23 June 2023 | 2 years, 9 days | [16][17] | |
| 2 | Agrawal, RajColonel Raj Agrawal | 23 June 2023 | 3 July 2025 | 2 years, 10 days | [18][19] | |
| 3 | Croker, Barry A.Colonel Barry A. Croker | 3 July 2025 | Incumbent | 148 days | [20] | |