SDB is a low-yield, all-weather precision guided munition designed to limit collateral damage and strike targets from up to 46 miles away.
Experimentation began in 2001 in response to an ACC requirement for a miniaturized precision weapon. Boeing was selected to fully develop and produce the weapon in 2003, and low-rate initial production began in 2005. Its size allows it to be carried in fighter or bomber internal weapons bays or to increase overall loadout for more independent strikes per sortie.
SDB I employs advanced anti-jam GPS/INS, and target coordinates are loaded on the ground or received from the aircraft before release. Several SDBs can be simultaneously released against multiple targets. The weapon was first employed by an F-15E over Iraq in 2006.
The Focused Lethality Munition (FLM) is a low-collateral version employing a carbon fiber case to limit damage to structures. Laser SDB is capable of self-targeting as well as GPS-only modes and is equipped with a selectable HOB fuse to tailor kinetic effects. Current production versions incorporate Strategic Anti-Jam Beamforming Receiver Y-Code (SABR-Y) for use in GPS-denied/degraded environments.
USAF reduced combat stockpile replenishment from over 2,000 weapons in FY21 to a total of 511 weapons in FY26, reflecting a shift to advanced standoff weapons to confront more advanced threats. USAF tested a dual-pylon-mounted GBU-39 configuration on the MQ-9 in 2025 as part of ongoing integration on the RPA.
GBU-39 Small Diameter Bomb I Technical Data
Contractor: Boeing.
First Flight: May 23, 2003.
IOC: Oct. 2, 2006.
Production: 24,000 (planned).
Active Variant: •GBU-39/B SDB I. GPS/INS-guided 250-lb low-yield bomb. •GBU-39A/B SDB I. GPS/INS-guided Focused Lethality Munition. •GBU-39B/B SDB I. Semiactive laser/GPS-guided 250-lb low-yield bomb.
Dimensions: Length 6 ft, width 7.5 in; BRU-61/A carriage (four bombs) length 12 ft, width 16 in, height 16 in.
Performance: Near-precision capability at standoff range up to 46 miles.
Guidance: GPS/INS.
Warhead: 250-lb class penetrating blast fragmentation munition.
Integration: A-10, AC-130J, F-15E, F-16, F-22, F-35A. Planned: B-1, B-52, B-21, MQ-9.