and catalog the objects. The need for real-time detection and tracking information to deal with Soviet satellite launches led on 19 December 1958 to ARPA's implementation of Executive Order 50-59 to establish a spacetrack network. This spacetrack network, Project Shepherd, began with the Space Track Filter Center at Bedford, Massachusetts, and an operational space defense network (i.e., a missile warning network). ARDC took up the spacetrack mission in late 1959 and in April 1960 set up the Interim National Space Surveillance Control Center at Hanscom Field, Massachusetts, to coordinate observations and maintain satellite data. At the same time, DOD designated the Aerospace Defense Command (ADCOM), formerly Air Defense Command, as the prime user of spacetrack data. ADCOM formulated the first US plans for space surveillance. During the years that intercontinental ballistic missiles were developing as frontline weapon systems, numerous missile detection and warning sensors were being experimented with and fielded as operational sensors and most of these contributed satellite observation data at one time or another. Many have been overlooked by current histories and additional research is merited. Among these were two Trinidad detection and tracking radars; Laredo, Texas; and Moorestown, New Jersey. Additional sensors that performed or contributed to space tracking but are not yet included in this page include mechanical tracking radars on the islands of Kaena Point, Antigua, Ascension Island, Naval Station San Miguel, and Kwajalein Atoll; the three BMEWS sites; the Pave Paws sites; the AN/FSS-7 missile warning radar sites; the Passive electronically scanned array sites; Cavalier, ND; Eglin, FL; Maui Space Surveillance System; Globus II; San Vito dei Normanni Air Station; TOS/CROSS; and MIT Lincoln Laboratory. Air Force Space Surveillance System The Air Force Space Surveillance System (AFSSS), also known as the "space fence", was a very high frequency radar network located at sites across the southern United States (from California to Georgia) with a centralized data processing site at the Naval Network and Space Operations Command in Dahlgren, Virginia. AFSSS began as the Navy's Space Surveillance (SPASUR) system in 1961 (later renamed NAVSPASUR). It was transferred to the Air Force in 2004 and renamed AFSSS. The "fence" was operated by the U.S. Air Force (20th Space Control Squadron Detachment 1). The Satellite Detection and Reconnaissance Defense (the former designation of the NSSS) reached initial operating capability in 1961. The role of the "fence" grew. The system detected space objects from new launches, maneuvers of