Operated by the US Strategic Command’s Joint Functional Component Command for Space (USSTRATCOM) since 1957, the SSN detects and tracks all man-made objects orbiting the Earth. About 78 percent of the objects tracked by SNN are debris and dead satellites. Using a ground-based radar and optical sensor network at 25 sites worldwide, SSN is capable of tracking objects 10 cm in diameter and larger.
SSN uses predictive analytics to monitor debris, spot checking their location rather than continuously tracking them. This is done using phased-array radars, conventional radars, and the Ground-Based Electro-Optical Deep Space Surveillance System (GEODSS).
Data from around the world is directed to the Space Control Center (SCC) tucked away in Colorado Springs, Colorado at the Cheyenne Mountain Air Station. This data is transmitted via every available means of communication so it can be accessed quickly: satellite, ground wire, microwave, and phone.
SSN also maintains a space catalog of all known satellites in orbit, recorded with an identification number. This data is made available through Space-Track.org. Search StuffIn.Space for a visual representation of the known locations of all satellites cataloged by the SSN.
Within European Space Agency’s (ESA) SSA program is their Space Surveillance and Tracking (SST) segment based in Darmstadt, Germany out of the European Space Operations Centre (ESOC). SST has proposed a dedicated system of telescopes, radars, and sensors to track orbital debris, improve collision avoidance systems, and create a new, updated catalog of debris in orbit.
The program is still under development. A loose network of prototype sensors were deployed worldwide between 2013 and 2016. Currently, the SST is focusing on software development and advancing sensor and hardware development.