Bolstering Its Space-Based Presence
DOD EYES MORE CAPABLE SBIRS AND STSS
PROGRAMS TO REPLACE FIELDED DEFENSE
SUPPORT PROGRAM SATELLITE SYSTEM
SBIRS is the military’s next generation of space-based early missile warning sensors and will eventually replace the legacy Defense Support Program satellite with improved missile warning and battlespace awareness capabilities. SBIRS is making improvements over DSP in the space-based infrared monitoring of the Earth with a wider field of view, increased sensitivity, fast revisit rate and persistent presence.
Space sensors already play a role in global missile defense by detecting the infrared signature emitted by missile launch exhaust systems. DSP has been performing that function for over three decades. SBIRS capabilities include two sensor payloads aboard host spacecraft already deployed in high elliptical orbit (HEO) and providing polar coverage. These HEO payloads will be complemented by four geosynchronous (GEO) satellites that will complete the SBIRS constellation. The first GEO launch is planned for December 2009. DSP added the last of its 23 satellites to its constellation in 2007, and will continue to operate until the SBIRS GEO satellites become operational, a process that will begin later this year.
As the SBIRS GEO satellites make their way toward launch, a third space-based missile defense program, the Space Tracking and Surveillance System (STSS), and an outgrowth of SBIRS, is also being developed to supplement SBIRS’ capabilities. DSP and SBIRS are run by the Air Force while STSS comes under the umbrella of the Missile Defense Agency.
The ultimate vision is for the Department of Defense’s space-based sensors to continuously track ballistic missiles, provide coverage in locations inaccessible to MDA’s Ballistic Missile Defense System (BMDS) radars and to pass tracking information to MDA’s battle management system and to BMDS interceptors. More accurate tracking data would allow additional and earlier missile intercept opportunities.
REPLACING THE WORKHORSE FOR MISSILE WARNING
“DSP has been the workhorse for missile warning for over 30 years, but is rooted in 1970s technology,” said Colonel John Kress, chief of the missile wing of the Air Force Space Command’s Missile Defense Operations Division. “SBIRS will provide modernized sensing technology and other engineering improvements in satellite construction and ground processing capability. This will result in greatly improved detection of infrared emissions and the processing of the data, which will in turn greatly increase operational decision- making in many mission areas.”
All of the DSP satellites have been launched and production has been terminated, Kress added. “Our plan is to continue to utilize DSP satellites on orbit as long as they are viable,” he explained. “Our ground capability will be sustained to continue commanding the satellites and processing the data, even as we move into the next generation missile warning satellite fielding. We’ll continue to closely monitor each currently operational satellite’s state of system health and its fuel supply. As we near the expected end of life for each satellite, our standard is to maneuver it to a safe disposal orbit.”
Both DSP and SBIRS support four mission areas: providing accurate reporting of missile launches; supporting the operation of missile defense systems; providing intelligence by gathering data on infrared signatures; and supplying infrared data to characterize battlespace conditions.
SBIRS’s advantages over DSP include advances in sensor technology to provide better sensitivity, faster revisit rates and faster detection of targets. In addition, the SBIRS system features more sophisticated programmability and tasking prioritization, which will provide better situational intelligence and more complete and accurate collection of event data.
“This will provide an increased ability to respond to any real-world situation at a moment’s notice,” said Colonel Roger Teague, commander of the Air Force’s Space Based Infrared Systems Wing. “When we receive intelligence that a certain situation might be occurring somewhere around the globe, we will have the ability to re-task SBIRS on a real-time basis to support the combatant commander who is responding to the situation.”
As a result, “SBIRS will provide much better accuracy and predictability with regards to the threat,” said Teague. “It will provide better battlespace awareness with increased and improved capabilities to detect short static events as well as enhanced tracking of moving targets.”
SBIRS sensors are designed to identify when a launch occurs, by detecting and tracking the infrared radiation from the missile’s hot exhaust. Onboard satellite systems process and transmit the data to relay ground stations, located around the globe, which in turn forward the data to the mission control station (MCS) for further processing. MCS software generates launch reports by fusing data from multiple satellites that include missile type, launch point and predicted impact point. Air Force Space Command operators then review these reports and release them to strategic and tactical users around the world.
“SBIRS was designed and is being deployed to counter ever-evolving missile threats,” said Teague. “SBIRS brings with it faster initial reports of events and earlier warnings of missile launches.”
SBIRS sensors represent an improvement over DSP’s by detecting short-wave and expanded mid-wave infrared waves allowing it to perform a broader set of missions that are not limited to missile warning. “There are certainly a number of scenarios and events the infrared sensors can detect,” said Teague. “We are trying to understand what kind of information those sensors can provide and what can be done in real time to provide tactical value to theater commanders.” This will involve, Teague explained, characterizing specific events based on the gathered infrared data and providing field commanders and forces with that information.
The SBIRS GEO spacecraft will be equipped with both a scanning sensor and a staring sensor. The scanning capability will take in a wide geographical area, while the staring sensor is a special capability that allows focus on specific geographic areas to support theater battlespace awareness. The GEO staring sensor will have high agility to rapidly stare at one Earth location and then step to other locations with improved sensitivity compared to DSP. Several areas can be monitored by the staring sensor with revisit times significantly smaller than that of DSP. A continuous staring mode will also provide an even smaller revisit time.
SBIRS involves a partnership between the Air Force and an industry team led by prime contractor Lockheed Martin. Lockheed is providing the space vehicle and all support and ground systems. Its principle subcontractor, Northrop Grumman, is providing the payload and sensor packages. The first phase of SBIRS, which involved replacement and consolidation of four legacy ground stations with a single MCS and backup, and new relay ground stations, has already been completed.
The January 29 baseline integrated system testing reconfirmed the reliability of all satellite functionality, according to Teague. “The test demonstrated the functionality of the SBIRS bird and all its components,” he said. “We have great confidence in the flight software development activity. We have incorporated lessons learned from the problems we had with previous versions. The new software controlled vehicle functionality very cleanly. We continue to march toward readiness for the launch of the first geosynchronous satellite.”
STSS
Another infrared tracking capability, currently in the experimental phase, is the Space Track and Surveillance Satellites (STSS). Originally part of the “SBIRS–Low” program, STSS is run by the Missile Defense Agency. STSS is still a demonstrations project and the timeline for a potential operational STSS has not been determined. The launch of the first of two STSS demonstration satellites is scheduled for the summer of 2009.
STSS contemplates the launch of two low-earth orbit research and demonstration satellites with infrared and visual sensors to track missile launches, midcourse travel, and atmospheric re-entry. Each satellite would use an infrared sensor for missile launch detection and a movable tracking sensor to follow objects in space. The STSS experimental satellites intend to demonstrate additional capabilities for identifying missile launches and tracking their trajectories, thus providing shooters with additional views and options for interception.
Like SBIRS, STSS represents a next generation capability to a currently deployed asset. STSS is intended to supply more sophisticated technology than SBIRS, with a gimbaled telescope that better tracks targets and two satellites that are able to hand off information to each other. STSS will also take technology to the next level with much more sophisticated infrared sensors. Measurements taken by STSS’s IR sensors will be integrated in the Ballistic Missile Defense System architecture in order to enhance SBIRS’ capabilities. STSS will be designed to improve on current capabilities by acquiring, tracking and disseminating reports on various ballistic missile events from liftoff to the re-entry period phases of flight. The idea behind STSS is to provide cues to the ground-based and sea-based portions of the BMDS architecture and to provide more of a global perspective than ground-based and sea-based radars can.
STSS grew out of the SBIRS program in the 1990s when it was called “SBIRS Low.” “After the program was canceled, the Missile Defense Agency built upon some of the SBIRS Low engineering and hardware products as it initiated the STSS space-based missile tracking program,” explained Debra Christman, MDA spokesperson for the program. “The near-term STSS demonstration satellites will be operated by MDA and will perform various tests and experiments. In the far term, the Air Force has been designated as the lead service for a potential operational STSS system. However, the concept of operations for operating the two systems to maximize capability and synergy is to be determined.”
STSS is best thought of as an eventual complement to SBIRS capabilities. “STSS was and still is the low earth orbiting portion of the SBIRS system of systems,” explained Lieutenant Colonel Andrew Smith, chief of the Missile Warning Requirements Branch of Air Force Space Command. “There are no plans, at present, to transition the two R&D satellites into an operational program.”
In fact, Congress prohibited the development of any operational STSS capabilities in the fiscal year 2009 defense authorization report. Congress contemplates “a successful launch and thorough analysis of the STSS demonstrator data” before funding any further development of STSS capabilities, the report said. But STSS continues with an extensive test and experiment plan. “During the first 90 days on orbit, a series of calibration and functionality tests will be accomplished,” said Christman. “Starting at launch plus three months, the system performance tests will begin. The test plan involves a crawl-walk-run approach, tracking missile surrogates at first, leading up to two dedicated missile tests.
The demonstration program also plans to make use of as many targets of opportunity as possible to test and evaluate the system. The demonstration system should be operational in the sense that it is ready to perform its on-orbit mission after the 90-day calibration and functionality test period.”
The STSS demonstration system is designed to take cues from SBIRS, DSP and MDA radars and demonstrate how hand-off can occur between different systems. “MDA is also planning experiments,” said Christman, “to demonstrate how data from numerous sensors can be fused into one system track.” That refers to a single stream of data about a particular target gathered from multiple sources and fed into the BMDS command, control, battle management and communications system.
While STSS capabilities may be fielded at some indefinite time in the future, SBIRS capabilities will start to be brought on line in short order. Thermal vacuum testing, which is designed to uncover design deficiencies and workmanship flaws in the spaceflight hardware of the first SBIRS GEO satellite, is scheduled for April, to be followed by final integration testing before launch. Assuming all goes well, Teague expects the second geosynchronous satellite will actually proceed ahead of schedule.
“SBIRS today is poised to deliver on the visions of the program,” said Teague, “to provide excellent missile warning intelligence and battlespace awareness capabilities. We have overcome past challenges, and we are increasingly excited about the prospect of getting new spacecraft on orbit and delivering their intended capabilities.” ♦