A Space Tracking and Surveillance System (STSS) Demonstration program satellite showed an increased set of capabilities when it detected and tracked a resident space object - another satellite - on July 19.

The missile defense satellite is one of two STSS spacecraft built by Northrop Grumman Corporation and Raytheon.

The STSS Demonstration program accomplished another first by tracking a National Oceanic and Atmospheric Administration (NOAA) weather satellite for several minutes using multiple track sensor bands, according to Gabe Watson, vice president of missile defense and missile warning programs for Northrop Grumman's Aerospace Systems sector.

Payload sensors on the U.S. Missile Defense Agency's (MDA) STSS satellite look both below the horizon, with Earth in the background behind the tracked target, and above the horizon, with space in the background behind the target.

This allows precision tracking of ballistic missiles through all phases of flight, commonly referred to as "birth-to-death tracking."

"Detecting and tracking a resident space object is yet another indication of the kinds of capabilities space-based sensors can bring to missile defense and the nation," Watson noted.

"Tracking the NOAA satellite was a significant accomplishment for the STSS test program because it represents precision tracking of a surrogate for a ballistic missile target in the midcourse phase."

The MDA is pursuing the STSS Demonstration program as a space-based sensor component of the Ballistic Missile Defense System.

The STSS satellites will provide missile defense sensor risk reduction concepts to support development and fielding of a future missile defense operational satellite constellation.