The enclosed Space Tracking and Surveillance System .

The enclosed Space Tracking and Surveillance System – Demonstrators, or STSS-Demo, spacecraft is being lifted into the mobile service tower on Cape Canaveral Air Force Station's Launch Pad 17-B. The United Launch Alliance Delta II launch vehicle is already in place in the tower. The STSS Demo is a space-based sensor component of a layered Ballistic Missile Defense System designed for the overall mission of detecting, tracking and discriminating ballistic missiles. STSS is capable of tracking objects after boost phase and provides trajectory information to other sensors. It will be launched by NASA for the Missile Defense Agency between 8 and 8:58 a.m. EDT Sept. 18. Approved for Public Release 09-MDA-04886 (10 SEPT 09) Photo credit: NASA/Jack Pfaller