The 20th Space Surveillance Squadron operated the AN/FPS-85 at Eglin Air Force Base. The 21st Space Wing also inherited the Ground-Based Electro-Optical Deep Space Surveillance System, which had detachments at Socorro, New Mexico, Diego Garcia, and Maui, Hawaii. Further developments included the instillation of the Transportable Optical System (TOS), later known as the Moron Optical Surveillance System (MOSS) at Moron Air Base, Spain. The Deep Space Tracking System (DSTS) was also inherited by the 21st Space Wing, being operated by the 3rd Space Surveillance Squadron out of Misawa Air Base, Japan, and the 5th Space Surveillance Squadron out of RAF Feltwell. The Low Altitude Space Surveillance System (LASS) was operated by the 1st Space Surveillance Squadron out of Griffiss Air Force Base, the 4th Space Surveillance Squadron out of Lackland Air Force Base and Osan Air Base, and the 17th Space Surveillance Squadron out of RAF Edzell. Command and control units inherited included the 721st Mobile Command and Control Squadron, 1st Command and Control Squadron out of Cheyenne Mountain Air Force Station, 2nd Command and Control Squadron out of Schriever Air Force Base, and the 3rd Command and Control Squadron out of Offutt Air Force Base. The 821st Space Group was activated at Buckley Air National Guard Base to centralize the management of the Defense Support Program. In 1997 the 84th Airlift Flight also transitioned to Air Mobility Command, ending the 21st Space Wing's last association with the flying mission. The 821st Space Group was inactivated in 2002, transferring the DSP mission to the 460th Air Base Wing. The 21st Space Wing also began moving to a counterspace mission, activating the 76th Space Control Squadron in 2001. The remaining space surveillance squadrons were redesignated as space control squadrons in light of their new mission role. On 20 December 2019 the 21st Space Wing, along with the rest of Air Force Space Command became part of the United States Space Force. The Fourteenth Air Force was redesignated as Space Operations Command, which the 21st Space Wing remained assigned to.