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.[1] The STSS program began in 2001, when the "SBIRS Low" program was transferred to MDA from the United States Air Force.[2]
Two demonstration satellites were launched together on a single Delta II launch vehicle.[3] Launch took place September 25, 2009, from Cape Canaveral Air Force Station Space Launch Complex 17.[4] 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.[5][6] It was reported[7][8] that several items of debris, identified by amateur satellite watchers as remnants of the Delta-2 launch vehicle,[9] 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.[10]
