US military ends satellite program that spotted missile launches

The US military has concluded its long-running Defense Support Program (DSP), a satellite initiative launched in 1970 to detect nuclear missile launches. The final operational DSP satellite was retired last month, marking the end of a program that played a significant role in American military space power during the Cold War.

The program began in late 1970 with the launch of a top-secret payload, later disclosed as a DSP satellite, aboard a Titan IIIC rocket from Cape Canaveral Air Force Station. These initial satellites, weighing about 1 metric ton, were equipped with approximately 2,000 infrared detectors and placed in geosynchronous orbit. Their primary function was to identify Soviet ICBM launches, serving as a critical component of nuclear deterrence.

Over the decades, the DSP constellation was expanded and upgraded. Later satellites increased in mass to about 2.5 tons and carried more than 6,000 infrared detectors. The program's utility extended beyond nuclear threats, proving effective in tracking conventional missile launches, such as Iraqi Scud missiles during conflicts. One satellite, DSP-16, was even launched by the space shuttle Atlantis in 1991. The DSP satellites continued to operate until 2007, with the final unit being retired last month.