GBU-39B Small Diameter Bomb
The GBU-39B Small Diameter Bomb (SDB) is a precision 250-pound class, extended-range, all-weather guided munition designed for high-efficiency strikes with minimal collateral damage. Using GPS/INS navigation, it autonomously guides to pre-programmed coordinates, allowing engagement of multiple fixed or stationary targets day or night. Its compact design enables aircraft to carry up to four SDBs per 1760-interface station on a smart BRU-61/A rack, significantly increasing sortie lethality while reducing the logistical footprint. With a standoff range exceeding 40 nautical miles, the SDB provides fighter and bomber crews the ability to conduct precise, multi-target strikes from safe distances, enhancing both operational flexibility and combat effectiveness.
General Info
- Origin: United States.
- Contractor: Boeing Co.
- Type: Glide, precision-guided bomb (250-lb class; penetrating/blast fragmentation or low-collateral variants).
- IOC (Initial Operational Capability): 2006 (first IOC declared Oct 2006).
- Guidance method: GPS/INS (near-precision, SAASM/anti-jamming GPS). Laser/terminal semi-active laser is available for the Laser SDB variant (GBU-39B/B).
- Primary missions: Precision strike / interdiction, close support where low collateral is desired, runway/point-target attack, OCA/strategic/tactical fixed-target strikes.
- Typical targets: Fixed and hardened point targets, bunkers, fuel/depots, critical infrastructure; Laser SDB can engage some moving or masked targets when designated.
- Platforms / integrations: Widely integrated or tested on multiple types — F-15E, F-16, F-22, Panavia Tornado, JAS-39, AC-130W (and planned/integration work for F-35, A-10, B-1, B-2, B-52, AC-130J, etc.).
Performance
- Reported accuracy (CEP): commonly reported in open sources between ~1 m (3 ft) and ~5–8 m (16–26 ft) depending on measurement mode, GPS/differential updates, and reporting source — most manufacturer/official material cites near-precision (~1 m CEP in surveyed conditions), while some analyses report 5–8 m CEP. Expect very high precision compared with legacy free-fall bombs.
- Air-foil / carriage: Diamond-back foldable wings (deploy after release) — carried in BRU-61/A quad racks (4× per BRU-61). (The BRU-61 is the standard carriage for SDB.) Boeing+1
- Minimum release altitude: Varies by desired standoff; official materials give standoff envelopes (higher altitude/airspeed → longer glide); specific low-altitude minima depend on aircraft/mission. (Public sources do not give a single universal “min release alt.” number suitable for all platforms.) Boeing
- Range / standoff: Greater than 60 nm (manufacturer data for high-altitude releases; operational range depends on release altitude/speed and aircraft). Boeing and fact sheets cite >60 nmi standoff in optimal conditions.
Warhead & Fuzing
- Warhead / explosive: Baseline SDB (SDB I / GBU-39/B) uses an insensitive-munition penetrating blast/fragmentation warhead with roughly ~36–37 lb of AFX-757 (publisher figures vary slightly). FLM (Focused Lethality Munition) variant uses a much lower-casualty focused-blast fill.
- Penetration: Public sources state penetration in excess of ~3 ft of steel-reinforced concrete for the penetrating variant.
- Fuzes / options: Electronic safe/arm fuzing with selectable modes (airburst, delayed, contact options depending on variant and implementation).