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Military Aerospace Technology

Small Bomb: On Target

After a delay, the Air Force has placed its first order for small diameter bombs and is proceeding with the program’s second phase.

By Peter A. Buxbaum

Although the small diameter bomb (SBD) program, especially in its second phase, has undergone a few twists and turns of late, it now appears to be on track.

The Air Force this spring ordered $18.5 million worth of SDB increment 1-related materiel from Boeing Integrated Defense Systems, to include 201 weapons and 35 carriages, and staged another in a series of successful tests in late July.

At the same time, the Air Force was considering its options on how to proceed with increment 2 after it decided to recompete that portion of the contract. A July report by the Pentagon inspector general upheld an earlier decision to hold a new competition for the second phase. Boeing estimates it will be asked to deliver 24,000 SDBs over the next 10 years, worth $2.5 billion to the company if it lands the second phase contract.

The small diameter bomb is a 250-pound munition with a 60 nautical mile standoff range, designed for deployment on fighters, bombers and unmanned combat air vehicles as a complement to the larger Joint Direct Attack Munition (JDAM). Increment 1 provides a GPS-guided smart weapon designed to hit stationary targets, while Increment 2 will add a series of technologies allowing the SDB to hit moving targets.

Increment 2 was one of the programs caught in the web of a conflict-of-interest scandal that plagued the Air Force procurement organization, and led to a decision to recompete that aspect of the SDB program. The big question facing SDB going forward is how it will fare in the Pentagon budget and whether its utility from a battle management perspective will be recognized given the existence of arguably duplicative smart artillery shells to be fielded by the Army.

SDB’s capabilities have been well tested. The weapon’s nose and body shape, as well as its smart fuse, allow for penetration of more than six feet of reinforced concrete with 50 pounds of explosive, the same penetration capabilities as a 2000-pound BLU-109, as demonstrated in a total of 21 Increment 1 flight tests.

The small munition has also met the key Air Force criterion of close to one weapon per target in tests targeting 14 hard and soft targets, including command, control, and communications bunkers; air defense assets; petroleum, oil, and lubricant sites; airfield targets; infrastructure targets; missiles; artillery; and AAA. The weapon boasts an Advanced Anti-Jam Global Positioning System-Aided Inertial Navigation System to provide guidance to the coordinates of stationary targets.

The SDB weapons system holds four SDBs in a carriage that fits aircraft external smart stations as well as the internal bays of the F/A-22, F-35, Joint Unmanned Combat Air System and bombers. The SDB will first be deployed on the F-15E Strike Eagle in 2006 and subsequently on the F/A-22, F-35 and others.

Moving Targets

A moving target engagement demonstration completed late last year at Eglin Air Force Base, FL, included a test of technologies that could be applied to SDB Increment 2. During the demonstration, mobile targets including a tactical missile launcher were successfully tracked and targeted. Ground-based Joint Terminal Attack Controllers (JTAC) relayed target geolocation coordinates via a Rockwell Collins Weapon Data Link and a Northrop Grumman multi-mode seeker to a Boeing SDB weapon pod.

The Air Force Research Laboratory (AFRL) said the demonstration proved the capability to “find, fix, track, target and engage tactical moving targets” and noted that the capability is applicable to SDB Increment 2 which will add a tactical weapons data link and terminal seeker to Increment 1.

“Last year, Eglin worked with [the Office of the Secretary of Defense] and major prime contractors to pursue a weapons data link advanced concept technology demonstration,” said Timothy Beyland, principal deputy, assistant secretary of the Air Force (acquisition and management). “These technology efforts are shared in a common forum to help the Department of Defense best understand the requirements for a weapons data link architecture and provide industry with insight where the department may make future investments.”

The SDB system evolved from a series of competitive weapons research programs conducted by the AFRL at Eglin Air Force Base from 1995 to 2000. The AFRL programs included miniature munitions technology, small smart bomb, smart multiple ejection rack and small smart bomb-range extension. The SDB Competitive Component Advanced Development program began in 2001 with the selection of two competitors: Boeing and Lockheed Martin.

SDB became part of the fallout over the conviction of Darlene Druyun, a former Air Force procurement official, for conflict-of-interest violations, during which she admitted bias in favor of Boeing on several procurements.

Druyun pleaded guilty in April 2004 to violating a law that prohibits a federal employee from participating in contract negotiations in which the employee has a financial interest. Druyun had arranged for Boeing to hire her daughter and son-in-law and later accepted employment herself with the company after she retired from the Air Force.

The GAO found that at the time of inception, SDB was a two-phase program that would develop a miniature munition to attack both fixed and mobile targets. But Druyun was found to have manipulated program requirements, removing the moving target component, in which Lockheed Martin was perceived to have the edge. She awarded the SDB contract to Boeing, and then added Increment 2 back into the program and sourced it to Boeing without conducting a competitive bidding process, according to GAO.

The GAO found that Druyun’s bias in favor of Boeing led to the removal of the program’s second phase from the bid and to the ultimate award of the contract to Boeing. The GAO findings contradicted the Air Force’s claims that Druyun was not involved in the decision to remove the second phase from the program. The GAO recommended that the Air Force recompete Increment 2, and the Air Force obliged.

The Air Force estimates that the Increment 2 contract could be worth a total of $1.7 billion, with deployment beginning in fiscal year 2009.

Technology Challenges

According to an AFRL statement, the moving target engagement demonstration “validates the system architecture Boeing is developing for” SDB increment 2. That capability involves “communicating target updates to data links and queuing the terminal seeker to the target area,” according to Dan Jaspering, Boeing’s SDB program manager.

The idea behind the moving target demonstration was to use a Rockwell Collins Weapon Data Link (WDL) to reduce the size of a moving target to a location of certainty, according to Steve Gardner, a Northrop Grumman program manager. Rockwell Collins and Northrop Grumman are both Boeing team members on the SDB Increment 2 project.

A Rockwell Collins WDL provided the moving target demonstration with in-flight target updates, according to Tom Vinson, a Rockwell program manager. The WDL used several waveforms, including Link 16, a standard situational awareness waveform used by the military. The WDL sent target updates to the Northrop Grumman multi-mode seeker “so that the weapon could be directed to the moving target. Then the seeker picked up the target and guided a surrogate weapon over the moving target,” Vinson said. Live fire was not used during the course of the demonstration.

“We had a multi-mode seeker on board underneath the aircraft along with the Boeing weapon pod,” Gardner explained. “The seeker and data link formed an arc within the mission computer to find several tactical and non-tactical targets moving up to about 20 miles per hour. The system demonstrated pretty good accuracy on the Eglin ranges.” Some of the testing was done under “relatively obscured conditions when the weather was not clear.”

The primary technological challenge in developing the moving target engagement capability was in interfacing the Weapon Data Link and the multi-mode seeker with the mission computer, an effort accomplished jointly by Boeing, Rockwell and Northrop, according to Vinson. “The integration challenge primarily involved understanding the information exchange requirement in terms of the types of messages we wanted to exchange and getting them all tied together,” he said. Another key challenge for Rockwell Collins was in miniaturizing the WDL terminal, reducing its size from 1,000 cubic inches to 50 cubic inches.

Going forward, Vinson said, the Rockwell hardware still has to be “productionized and qualified for the environments it will be playing in.” The process could make the equipment ready for deployment in 2009 or 2010.

Army Excalibur

The Air Force is likely to proceed with SDB Increment 2 “cautiously until after the SDB has some combat experience,” said military analyst James F. Dunnigan.

Dunnigan’s theory is that the ultimate utility and further development of SDB will depend on its use in combat. He points to the Army’s Excalibur smart artillery shell as a munition that could play a similar role in combat to the SDB and could give it a run for the money, especially in light of the fact that the Pentagon is seeking to trim duplicative programs from the budget.

The GPS-guided Excalibur, which will be issued to artillery units within the next year, is expected to cost about $50,000 each--around the same as SDB. It will be able to land a shell within 30 feet of a target, according to Dunnigan.

“Actual tests have shown the shells will land within half that distance,” he said. “The Army wants this kind of accuracy for fighting in urban areas, and to reduce the number of shells needed to destroy a target. Accuracy in urban areas reduces civilian casualties, and allows friendly troops to be closer to the target. Having your troops closer to the target allows the infantry to rush in after the shell hits and quickly mop up the surviving enemy troops. This reduces your casualties, and puts the fear of Excalibur into the enemy troops.”

The SDB, Dunnigan added, weighs twice as much as Excalibur, and thus produces a bigger bang. “But you need an Air Force bomber overhead to get an SDB, while Army artillery is always there,” he said. “You also need an Air Force forward air controller nearby to call in the bomb, while there are many more Army personnel who can call for artillery.”

In actual combat situations, Dunnigan believes the Army will tend to use Excalibur, even if SDB is available. “Because communications are faster between Army troops and artillery, than with Air Force bombers,” he said, “it’s more effective to use Army smart shells than Air Force smart bombs.”

The Army also has some other new Future Combat Systems missiles that compete with SDB, according to Dunnigan. “For the Army, it’s always easier to use their own smart weapons,” he argued.

But Boeing does not appear to be worried by that analysis. “There is a lot of support for SDB in the Air Force,” said Boeing program manager Dan Jaspering. “It’s been fully funded from the get-go and now is it going into production.”