The Missile Defense Alarm System, or MIDAS, was a United States Air Force Air Defense Command system of 12 early-warning satellites that provided limited notice of Soviet intercontinental ballistic missile launches between 1960 and 1966. Originally intended to serve as a complete early-warning system working in conjunction with the Ballistic Missile Early Warning System, cost and reliability concerns limited the project to a research and development role. Three of the system's 12 launches ended in failure, and the remaining nine satellites provided crude infrared early-warning coverage of the Soviet Union until the project was replaced by the Defense Support Program. MiDAS represented one element of the United States's first generation of reconnaissance satellites that also included the Corona and SAMOS series. Though MIDAS failed in its primary role as a system of infrared early-warning satellites, it pioneered the technologies needed in successor systems. Origins On October 4, 1957, from the Tyuratam range in the Kazakh SSR, the Soviet Union launched Sputnik 1, the world's first artificial satellite. The event, while a scientific triumph, also signified that the Soviet Union now had the capability to attack the United States with an intercontinental ballistic missile (ICBM). The R-7, the booster rocket that launched Sputnik 1 and Sputnik 2, could be loaded instead with a hydrogen bomb, bringing the threat of a surprise nuclear Pearl Harbor-style attack on the United States and Canada. To give an early warning of any Soviet sneak ICBM attack, the governments of the United States, Canada, and Denmark (with the authority over Greenland, where the main radar station was built at Thule Air Base) agreed to build the Ballistic Missile Early Warning System (BMEWS). This system would use radar to detect incoming ICBM warheads and give about 20 minutes of warning of an ICBM attack. However, this system was hampered by the inherent limitations of radar systems and the curvature of the Earth. Due to the location of the Soviet Union on the other side of the Northern Hemisphere, the potential Soviet ICBM sites were thousands of miles over the horizon from the BMEWS radar stations that were under construction at Thule and Clear Air Force Station, Alaska (and later on, in England), and the BMEWS stations, as huge as they are, could not detect the ICBM warheads immediately after their launching. Only when the warheads had risen above the horizon could they be detected and warnings passed