A key Senate panel wants the Air Force to brief the congressional defense committees on the status of the entire Small Diameter Bomb (SDB) program, which it says is approaching critical program milestones.

The Senate Armed Services Committee (SASC) said in its fiscal year 2014 defense authorization report the briefings should include the current status of the SDB II test program, potential gaps in capabilities if SDB II testing were to be delayed, an examination of the mix of SDB I and SDB II weapon capabilities and costs and a recommended way ahead for SDB procurement. SDB I is designed for stationary targets while SDB II is for moving targets.

Boeing’s Small Diameter Bomb. Photo: Air Force.

The committee said the Air Force plans to start low-rate initial production (LRIP) of SDB II in 2014. The committee said earlier this year the SDB II flight test program was temporarily suspended due to a flight test failure, but has since resumed. SASC said any further SDB II delays could affect the timing of Milestone C, currently scheduled for August, and could cause a delay in having required assets available to outfit a F-15E squadron in late 2016.

Raytheon [RTN] is developing the SDB II. Boeing [BA] produces the SDB I as well as the F-15E.

Raytheon last July successfully hit a moving target with SDB II during its first guided test flight. Raytheon has developed a tri-mode seeker (radar, infrared and semi-active laser) for SDB II, adding on to the first SDB’s use of global positioning system (GPS) and inertial navigation system (INS) data to achieve required precision. These new sensors are intended to provide automatic target recognition features for striking mobile targets, like tanks, vehicles and mobile command posts, SASC said.

SASC said it is aware of a possible modification to the SDB I that would add a semi-active laser (SAL) sensor, which could provide some, but not all, of the potential SDB II capability against moving targets. The committee urged the Air Force to consider this option if there were additional SDB II flight testing difficulties that could cast doubt on the success of the program.

SDB-I, or GBU-39B, is an extended range, all-weather, day-or-night, 250-pound class guided munition. Its small size allows increased aircraft loadout to achieve multiple kills per sortie and inherently reduces the probability of collateral damage, according to the Air Force.

The Air Force in February said it performed a “fit check” of the SDB-II on the F-35, where four SDB II shapes were loaded into a weapons bay (Defense Daily, Feb. 4). The F-35 is developed by Lockheed Martin [LMT].