The Space Tracking and Surveillance System (STSS) demonstration satellites continue to shine in their role as space sensors validating key functions and capabilities for missile tracking.

"Even before observing the second anniversary on Sept. 25, 2011, of their tandem launch, the nearly identical satellites already had completed on-orbit mission objectives ahead of schedule," said David Bloodgood, STSS program manager for Northrop Grumman's Aerospace Systems sector.

"They demonstrated the 22nd and last 'test focus area' defined by the U.S. Missile Defense Agency [MDA] five months ahead of schedule to support on-orbit demonstration of mission objectives." Northrop Grumman (NYSE:NOC) is the prime contractor for STSS and Raytheon Company is the sensor payload provider.

The final test focus area objective was demonstrated in April during an Aegis FTM-15 flight test when STSS demonstrated the capability to provide real-time, fire-control quality data to the Aegis weapon system to support launch on remote.

"This demonstration was originally planned to be accomplished with data from a dedicated test scheduled for September 2011, 24 months after the STSS demonstrators were launched," said Bloodgood.

"It's remarkable that the integrated Northrop Grumman, Raytheon and MDA team was able to use system cueing and the inter-satellite communications crosslink between the two STSS satellites to acquire and track the target during FTM-15. That allowed the final test focus area to be demonstrated during an Aegis test against an intermediate range target," he added.

"The original plan was to use dedicated targets to demonstrate STSS capabilities. It was very challenging to meet all test focus areas using shared targets during other MDA system tests."

On the second anniversary of their launch, the pair of satellites also had:

+ Orbited the Earth 9,333 times

+ Made 845 vehicle collects

+ Communicated with the Air Force Satellite Control Network 11,429 times

+ Received 3,405,712 commands

"The STSS demonstration satellites have been extremely productive during their two-years on orbit, proving the advantages of space sensors for missile defense many times over," said Doug Young, vice president of missile defense and warning programs for Northrop Grumman's Aerospace Systems sector.

Altogether, Young said, the demonstration satellites participated in multiple flight tests in MDA's Integrated Master Test Plan to validate key objectives in three main categories: (1) Birth-to-death tracking, (2) Launch-on-remote, and (3) Risk reduction for a future operational capability and 4) providing precision cues to BMDS radars. In addition to birth-to-death tracking, highlights of the on-orbit demonstration included:

+ Tracking six Ballistic Missile Defense System (BMDS) threat-representative targets, and a number of other space objects or satellites

+ Generating "stereo" or 3-dimensional missile tracks, yielding the best quality data yet seen from a space-based sensor, and

+ Participating in Aegis launch-on-remote exercises, demonstrating the ability to launch interceptors based on remote track data from space.

"By meeting the major objectives ahead of schedule, we have delivered first-time capabilities for missile defense that are valuable for our national security that also are a good value for taxpayers," Young added. "All technologies on STSS have a very high technology readiness level. This reduces the risk, and ultimately the cost, of MDA's long-term strategy of fielding a constellation of precision tracking satellites as a key BMDS element."

The two low-earth orbiting STSS demonstrators will continue participating in BMDS tests during the remainder of fiscal years 2011 and 2012 in conjunction with

other components.

On-Orbit Major Accomplishments
June 2010

+ 1st on-board missile track formed (BVT-01)

+ 1st dual satellite collect of target (GT-200) (acquisition sensor)

+ 1st OSMs sent to Enterprise Sensors Laboratory (Schriever Air Force Base) for data fusion with other sensors (real time) (FTT-14)

+ 1st track of a dim theater missile (FTT-14)

July 2010

+ 1st autonomous acquisition-to-track sensor handover of a target (ground laser source)

August 2010

+ 1st autonomous acquisition-to-track sensor handover of a boosting target (FEL-01B)

September 2010

+ 1st post-boost track continuation of a target with track sensor (mono) (GT-202)

+ 1st demo of track sensor generating multiple tracks for separating objects

October 2010

+ 1st track sensor stereo track of a dim boosting target (JFTM-04 E1)

+ 1st stereo post boost tracking of midcourse target (JFTM-04 E1)

+ 1st stereo track of a resident space object

November 2010

+ Completed final early on-orbit test

December 2010

+ 1st stereo track of a resident space object using the long-wave infrared sensor

January 2011

+ Completed final test to satisfy Missile Defense Agency's Knowledge Point No. 1

March 2011

+ Demonstrated STSS' ability to "detect intercept"

+ 1st birth-to-death track of a ballistic missile target (FTM-16)

+ 1st birth-to-death stereo track of a ballistic missile target (FTX-16)

April 2011

+ Acquired a target missile during the midcourse phase of its flight after being cued remotely.

+ 1st use of inter-satellite crosslink for cueing and passing data

+ 1st live Aegis remote engagement authorized using STSS data

+ 1st view of an intercept

July 2011

+ Acquired and tracked short-range, air-launched target (dim object with short flight timeline)