The Space Tracking and Surveillance System (STSS) demonstration satellites successfully acquired and tracked a short-range, air-launched target (SRALT) July 8 in a test that showed their ability to track dim objects that have extremely short flight timelines.

The satellites were built by Northrop Grumman Corporation, prime contractor, and Raytheon Company, sensor payload provider, for the U.S. Missile Defense Agency (MDA). The exercise verified target capabilities and did not involve an intercept attempt.

"Air-launched targets have a wide variety of trajectories. There's nothing predictable about their flights. The STSS demonstrators successfully tracked this target and collected key data about test conditions and the dynamics of air-launched targets that will be valuable for MDA's predictive capability," said Doug Young, vice president of missile defense and missile warning programs for Northrop Grumman's Aerospace Systems sector.

One single-stage, solid-fueled rocket was drop-launched from the rear of a C-17 cargo aircraft by MDA over the Pacific Ocean Test Range near San Nicolas Island off the Central California coast. The SRALT was selected as a target because it closely replicates realistic engagement scenarios.

"This was the first time the STSS sensors have been tested against air-launched targets, and they performed flawlessly," said Bill Hart, vice president, Raytheon Space Systems. "Against such short-range targets, split seconds count. That's why a near-immediate reaction system like STSS is so important to our national defense."

Plans call for the STSS satellites to continue on-orbit testing by participating in a series of performance demonstration tests with ground, airborne, resident space objects and ballistic missile targets to reduce the risk of an operational constellation of space-based sensors for missile defense.

According to MDA, the additional flight tests will demonstrate the ability to track various targets, providing critical demonstrator performance characterization while progressing towards closing the fire control loop with Ballistic Missile Defense System (BMDS) interceptors using space-based infrared tracking.

MDA is operating STSS as an experimental space layer of the BMDS. Using sensors capable of detecting visible and infrared light, the STSS satellite constellation is part of a collection of land-, sea-, air- and space-based BMDS sensors. They are gathering critical engagement conditions and empirical measurement event data, among other missions.