Space Tracking and Surveillance System (STSS)

The Missile Defense Agency's Space Tracking and Surveillance System is a research and development capability for the Ballistic Missile Defense System that can detect and track ballistic missiles and other cold objects in space.

STSS consists of two satellites carrying sensor payloads in a low-Earth orbit. Raytheon developed the sensor payloads for the two STSS satellites under contract to Northrop Grumman, prime contractor for the STSS program. The STSS payloads are able to detect infrared and visible light.

The STSS spacecraft demonstrate the value of space-based sensors to missile defense. Since they were launched in 2009, the STSS sensor payloads have demonstrated the ability to:

  • Detect missile launches and track targets from boost phase into midcourse
  • Acquire and track short range air-launched targets
  • Track multiple targets simultaneously
  • Communicate with missile defense command and control systems
  • Provide "launch on remote" cueing information to U.S. Navy ship defenses before the ship itself acquired the target