Two recent Ballistic Missile Defense System-wide (BMDS) tests involving the Northrop Grumman-built Space Tracking and Surveillance System (STSS) Demonstration satellites showed that the satellite system can successfully perform the ultimate mission for space-based missile defense sensors - full-course, or 'birth-to-death' tracking of a ballistic missile.

"This is the first time a space-based sensor has tracked a ballistic missile through all phases of its flight, from launch, through midcourse and re-entry," said Doug Young, vice president, missile defense and warning for Northrop Grumman's Aerospace Systems sector in Redondo Beach, Calif.

"This birth-to-death tracking ability optimizes interceptor selection and enables the interceptor to compensate for maneuvering midcourse objects."

Young said the success came in two stages. Each time, the test target was an Aegis Readiness Assessment Vehicle. On March 9, one of the STSS satellites acquired and tracked its target until re-entry during a test designed to validate Aegis system software upgrades. The timing of the launch was coordinated between Aegis and STSS to assure visibility of the launch.

On March 15, both STSS satellites demonstrated full-course tracking once again during a portion of the U.S. Missile Defense Agency's (MDA) Aegis launch on remote campaign. Both satellites acquired the target through their track sensors and followed the missile through re-entry.

During this test, the Ground Mission Data Processing software, operating at the Missile Defense Experimentation Center, successfully produced a "stereo," 3-D track of the missile's flight path, predicting its impact point in advance.

"This is missile defense history in the making," said David Bloodgood, the company's STSS program manager.

"It's the first time a single set of sensors has followed a missile from launch through re-entry or intercept. Before now, it took a combination of sensors in space, on the ground, in the air and at sea to do what the two STSS demonstrators accomplished by themselves."

The STSS Demonstration program plays an integral role in MDA's long-term strategy to field a constellation of precision tracking satellites as a key element of the BMDS.

The STSS satellites are demonstrating the feasibility of a space sensor to provide high-precision, real-time tracking of missiles and midcourse objects, enabling simultaneous regional, theater and strategic missile defense.