The Tracking and Data Relay Satellite (TDRS) K/L Project is providing follow-on and replacement spacecraft necessary to maintain and expand the Space Network. The contract to build two additional TDRS spacecraft, known as TDRS K and L, was awarded to Boeing Space and Intelligence Systems in December 2007. TDRS K is scheduled for launch in 2012, and TDRS L is scheduled for launch in 2013.  The contract also has options for two additional spacecraft, TDRS M and N. In addition to building the TDRS K and L spacecraft, the contract also includes the modifications to the White Sands Complex (WSC) ground system required to support these new spacecraft.

The TDRS Project was established in 1973 and is responsible for the development, launch, and on-orbit test and calibration of TDRS spacecraft. There have been four procurements of TDRS spacecraft, which include the Basic Program (TDRS F1-F6), the Replacement Program (TDRS F7), the TDRS H,I,J Program, and the TDRS K/L Program.  TDRS Flight 7 was a replacement for Flight 2, which was lost on Challenger.  The first seven spacecraft (TDRS F1-F7) are referred to as the First Generation, the H,I,J series the Second Generation, and the K/L series the Third Generation.  TDRS F1-7 spacecraft were built by TRW (now Northrop Grumman) in Redondo Beach, CA.  The TDRS F8-10 (H,I,J) spacecraft were built by Hughes (now Boeing) in El Segundo, CA. 

The TDRS system (TDRSS), also referred to as the NASA Space Network, consists of the on-orbit telecommunications TDRS satellites stationed at geosynchronous stationary positions and the associated TDRS ground stations located at White Sands, New Mexico and Guam. The TDRSS is capable of providing near continuous high bandwidth (S, Ku, and Ka band) telecommunications services for low Earth orbiting user spacecraft and expendable launch vehicles, including the Hubble Space Telescope, the space shuttle and the space station.  As such, the TDRS System is a basic agency capability and a critical national resource.