The upper stage of this Lockheed Martin Atlas Centaur rocket encloses the Tracking and Data Relay Satellite the second.

The upper stage of this Lockheed Martin Atlas/Centaur rocket encloses the Tracking and Data Relay Satellite-I (TDRS-I), the second in a new series of telemetry satellites that are replenishing the existing on-orbit fleet of six spacecraft. The TDRS System is the primary source of space-to-ground voice, data and telemetry for the Space Shuttle. It also provides communications with the International Space Station and scientific spacecraft in low-Earth orbit such as the Hubble Space Telescope. This new advanced series of satellites will extend the availability of TDRS communications services until about 2017. Launch of TDRS-I atop the Atlas rocket is scheduled today between 5:39 - 6:19 p.m. EST from Launch Pad 36-A, Cape Canaveral Air Force Station