Raytheon Trimode Seeker Work Progresses With SDB II

Raytheon officials insist the Small-Diameter Bomb II, a sophisticated weapon for the Pentagon designed to destroy moving targets, will be ready for production in 2014 despite a delay in the development project.

The SDB II is being readied for a second guided-test-vehicle flight trial this month after a successful, albeit delayed, first shot in July.

During the July 17 test, the 250-lb. glide bomb used two of three modes in the complex trimode seeker—the imaging-infrared and millimeter-wave radar—to engage a ground target moving at “operationally relevant” speeds, says John O'Brien, Raytheon's SDB II program director. These two modes, used in concert, are considered the most complicated pieces of the tri-mode seeker, thus the early focus on proving these elements.

The SDB II is also being designed to operate with the BRU-61 bomb rack used for the first version of the SDB, a penetrating version of the weapon designed to have GPS and inertial guidance and a 40-nm range. Boeing builds SDB, but the company—teamed with Lockheed Martin—lost the contract to Raytheon to build the moving-target version. Using the BRU-61 carriage system, the Air Force can place four SDBs of either type in a single position typically occupied by a 1,000- or 2,000-lb. Joint Direct Attack Munition, quadrupling the number of targets that can be struck with a single F-35 or F-22 sortie.

The test delay—moving it from January to July—was primarily driven by immaturity of the systems integration laboratory facility needed to support testing leading up to the demonstration, O'Brien said. Some of the software, hardware and computer in-the-loop bench testers were still being developed in January, according to Maj. Gen. Kenneth Merchant, Air Force program executive officer for weapons. “The sequence is getting better. We are focused on that,” O'Brien adds.

Additionally, there were some software delays, Harry Schulte, vice president of air warfare systems, told Aviation Week during this summer's Farnborough air show outside London.

Although some program milestones are also delayed, owing to the late first flight, O'Brien says the team is still focused on achieving production readiness in 2014, but he concedes that a major system verification review, set for next summer, will be a challenge to execute by fall 2013.