The Space Tracking and Surveillance (STSS) Demonstration program satellites are ready to fully participate in Ballistic Missile Defense System (BMDS) tests after on-orbit calibration of the acquisitions and track sensors for both spacecraft was completed Nov. 3 by prime contractor Northrop Grumman, and infrared sensor payload provider Raytheon.

Calibration of those sensors was the last major step during the on-orbit tests of the space vehicles, which were launched Sept. 25, 2009, in tandem configuration from Cape Canaveral Air Force Station, Fla.

"We are confident that upcoming BMDS tests involving STSS will generate the kind and quality of data that will validate our projections of the value of space-based sensors for missile tracking," said Doug Young, vice president of Missile Defense and Warning Programs for Northrop Grumman's Aerospace Systems sector. He noted the data will validate models used to define an operational system.

"STSS brings unique capabilities to missile defense. It's the only system capable of tracking ballistic missiles through all phases of flight, starting with boost extending through midcourse and terminal phases," Young added.

"In 2010, the satellites demonstrated many capabilities essential to performing their missile defense role in initial exercises, such as tracking U.S. missile test launches. While those were not operational tests, they point to the potential applications of this satellite technology."

Using sensors capable of receiving infrared radiation, the STSS demonstration satellites are able to detect missile launches, provide continuous target tracking and communicate with missile defense command and control systems.

The STSS Demonstration satellites will be integrated into MDA's overall testing strategy that calls for multiple missile defense elements to participate in each test event.

"Integrated tests involving multiple BMDS elements will provide opportunities for STSS to demonstrate a wide range of missile tracking capabilities geared toward decisions regarding required future operational systems capabilities," Young said.

These capabilities include boosting missile detection and tracking; midcourse object tracking and characterization; missile track handover between the two space vehicles; and interceptor cueing via downlink communications to the ground station.