Satellite Data System (SDS) spacecraft are communication relay satellites for transmitting real-time data from US reconnaissance satellites (e.g. KH-11) in polar areas. They are also used for communications to USAF air craft on polar routes and connect the various ground stations of the Air Force Satellite Control Network (AFSCN). The spacecraft relay the downlinked data to a ground station at Fort Belvoir, Virginia.
These satellites are the third generation of the system, the SDS-3. Some of them (#12, #15, #16) are in highly elliptical Molniya orbits, but the other (#13, #14, #17, #18) have a geostationary position. #19 will also be launched into a geostationary orbit. Unlike the Trumpet Follow On ELINT satellites, the SDS-3 satellites are not placed directly into the Molniya orbit, but use a lower apogee transfer orbit.
The code-name QUASAR has been confirmed by leaked budgets in 2013 to be associated with these satellites.
There are reports, that the satellites launched from 2011 onwards might represent a fourth generation.
Note: The numbering is not sure, as it is not confirmed, how many first generation Quasar were launched.
|Type / Application:||Comsat / Relay, early warning|
|Orbit:||Molniya Orbit (#12, #15, #16), GEO (#13, #14, #17, #18, #19)|
|Quasar 12 (SDS-3 1, USA 137, NROL 5)||1998-005A||29.01.1998||CC SLC-36A||Atlas-2A|
|Quasar 13 (SDS-3 2, USA 155, NROL 10)||2000-080A||06.12.2000||CC SLC-36A||Atlas-2AS|
|Quasar 14 (SDS-3 3, USA 162, NROL 12)||2001-046A||11.10.2001||CC SLC-36B||Atlas-2AS|
|Quasar 15 (SDS-3 4, USA 179, NROL 1)||2004-034A||31.08.2004||CC SLC-36A||Atlas-2AS|
|Quasar 16 (SDS-3 5, USA 198, NROL 24)||2007-060A||10.12.2007||CC SLC-41||Atlas-5(401)|
|Quasar 17 (SDS-3 6, USA 227, NROL 27)||2011-011A||11.03.2011||CC SLC-37B||Delta-4M+(4,2)|
|Quasar 18 (SDS-3 7, USA 236, NROL 38)||2012-033A||20.06.2012||CC SLC-41||Atlas-5(401)|
|Quasar 19 (SDS-3 8, USA 252, NROL 33)||2014-027A||22.05.2014||CC SLC-41||Atlas-5(401)|