The United States Missile Defense Agency is developing a Space Tracking and Surveillance System 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.
Launch
One of the two satellites had been shipped to Cape Canaveral 4 May 2009; the second satellite arrived at the launch site on 25 June 2009. Two demonstration satellites were launched together on a single Delta IIlaunch vehicle. Launch took place 25 September 2009, from Cape Canaveral Air Force Station Space Launch Complex 17. STSS constellation consists of two satellites orbiting at 1350 km, 58° inclination, with 120 minute orbital period. 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 19 February 2010.
Early detection
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.
The role of STSS
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 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 during a U.S. Missile Defense Agency flight test on 6 June 2010.
Congressional testimony
According to Congressional testimony, military officials believe that STSS has the potential to bolster the nation's missile defense system. “Two recent flight tests demonstrated that STSS dramatically improved the precision of threat missile attacks and provided more accurate fire control quality data to the Aegis ships several minutes earlier than less accurate data provided by organic radars in the Aegis or THAAD systems”, U.S. Army Lt. General Patrick J. O’Reilly, Director of the U.S. Missile Defense Agency, told the U.S. Senate Appropriations Committee's Defense subcommittee in prepared testimony on 25 May 2011.
Timeline of STSS testing
According to Global Newswire press releases, the following is a summary of the STSS Demonstration program satellites' on-orbit performance. June 2010 Ground-Based Interceptor test launch – 06 June 2010 First STSS Object Sighting Messages of a missile First on-board missile track formed ICBM Minuteman III test launch – 16 June 2010 First dual satellite collect of target, and First target acquisition from a target launched beyond the horizon Terminal High Altitude Area Defense system test – 28 June 2010 First OSMs sent to Enterprise Sensors Laboratory at Schriever Air Force Base, Colo., for data fusion with other sensors in real time First track of a dim theater missile July 2010 First track of a resident space object – 19 July 2010 Tracked a NOAA weather satellite 19 July 2010 for several minutes First autonomous acquisition sensor to track sensor handover of a target – 23 July 2010 Hand-off demonstration occurred when STSS acquired a ground laser source operated by U.S. Air Force Research Laboratory from the Starfire Optical Range at Kirtland Air Force Base, NM August 2010 First track of an aircraft Precision track sensor operation below the horizon during daylight – 05 August 2010 First autonomous acquisition sensor to track sensor handover of an aircraft September 2010 Airborne Laser Test Bed Exercise – 01 September 2010 First autonomous acquisition sensor to track sensor handover of a boosted target ICBM Minuteman III test launch – 17 September 2010 First post boost track continuation of a target with track sensor First demonstration of track sensor generating multiple tracks for separating objects October 2010 Aegis Launch on Remote Campaign First Track sensor stereo track of a dim boosted target First stereo post boost tracking of midcourse target March 2011 Second Aegis Readiness Assessment Vehicle Targeting – 09 March 2011 STSS satellites acquired and tracked its target until re-entry Second full-course tracking during U.S. Missile Defense Agency's Aegis launch – 15 March 2011 Successful production of "stereo" 3-D tracking software to follow the target missile's flight path to predict its impact point April 2011 Sea-based missile defense test – 15 April 2011 STSS satellites target and help to intercept an intermediate-range ballistic missile ; destruction of the IRBM on impact July 2011 STSS test on short-range, air-launched target – 08 July 2011 This test proved the STSS's ability to track dim objects that have extremely short flight timelines
