Space Tracking and Surveillance System

The United States Missile Defense Agency (MDA) is developing a Space Tracking and Surveillance System (STSS) which it will use to research the space-based detection and tracking of ballistic missiles. Data from STSS satellites could allow interceptors to engage incoming missiles earlier in flight than would be possible with other missile detection systems. The STSS program began in 2001, when the "SBIRS Low" program was transferred to MDA from the United States Air Force.

Two demonstration satellites were launched together on a single Delta II launch vehicle. Launch took place September 25, 2009, from Cape Canaveral Air Force Station Space Launch Complex 17. One of the two satellites had been shipped to Cape Canaveral May 4, 2009; the second satellite arrived at the launch site on June 25, 2009. It was reported that several items of debris, identified by amateur satellite watchers as remnants of the Delta-2 launch vehicle, had crashed in a field in Mongolia on the February 19, 2010.

The perceived advantage of STSS is that its satellites, by operating at a lower altitude and by using long- and short-wave infrared sensors, will be able to acquire and track missiles in midcourse and during the boost phase.

STSS is designed to be the low earth orbiter within the layered Ballistic Missile Defense System. It complements the geosynchronous Defense Support Program, the Space-Based Infrared System, and other Overhead Non-Imaging Infrared systems (ONIR) and provides tracking cues to systems on the surface. The STSS program is developed in phases, the first of which is the launch of two demonstrator satellites. The demonstrators will perform experiments and prove out systems and processes to establish a knowledge base for future operational designs. The demonstration satellites, built by Northrop Grumman and Raytheon detected and tracked a two-stage Ground-Based Interceptor (GBI) during a U.S. Missile Defense Agency flight test on June 6, 2010.

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