Munitions

GBU-39/B Small Diameter Bomb I

Also known as
  • GBU-39
  • GBU-39/B
  • SDB
  • SDB I
  • Small Diameter Bomb I
  • Small Diameter Bomb

The GBU-39/B Small Diameter Bomb I is a U.S.-built 250-pound GPS/INS-guided glide bomb for standoff precision strikes from aircraft that can carry multiple weapons per rack. Boeing and Air Force sources tie the SDB I to F-15E, F-16, F-22, F-35A, AC-130, bomber, and later MQ-9 integration paths, while direct conflict reporting documents combat use in Iraq, Afghanistan, Operation Inherent Resolve, Ukraine, and Gaza.

GBU-39/B Small Diameter Bomb I, 250-pound GPS/INS-guided glide bomb, Munitions
Image source: 201128-Z-OK775-012

Role in Conflicts

Design Notes

The GBU-39 was built to give tactical aircraft more precision shots per sortie without giving up standoff range.

Compact size

Official sources describe a 250-pound class GPS/INS-guided glide bomb.

Loadout density

Air & Space Forces reports that one BRU-61/A rack can carry four GBU-39s.

Carrier fit

Air Force procurement material lists integrated fighters, gunships, and planned objective aircraft, while AFSOC documents MQ-9 carriage through the BRU-78 system.

Profile / Specs

Profile

Origin
United States
Built by
Boeing
Type
250-pound GPS/INS-guided glide bomb
Service note
2006-present
Designer
Boeing Integrated Defense Systems
Designed
2001-2003
Unit cost
About $40,000
Produced
2005-present
Number built
Not publicly stated

Specifications

Weight
268 lb (122 kg)
Length
70.8 in (1.8 m)
Range
Greater than 60 nautical miles in Boeing product material; Air Force fact sheet lists more than 40 nautical miles
Guidance
GPS-aided inertial navigation with anti-jam GPS and SAASM
Warhead
250-pound class penetrating blast-fragmentation
Carriage
BRU-61/A carriage holds four SDB I weapons per 1760 store location; MQ-9 integration uses the BRU-78 Dual Carriage System
Targets
Fixed or stationary targets such as fuel depots and bunkers
Variants

Public sources use SDB I and GBU-39/B for the original GPS/INS Small Diameter Bomb family; related designations distinguish warhead or guidance changes rather than a separate page for each configuration.

VariantConfigurationDesignation notes
GBU-39A/BFocused Lethality Munition

Air Force procurement material lists the GBU-39A/B as the Focused Lethality Munition configuration within the SDB I family.

Sources: FY22 DAF Missile Procurement Justification Book

GBU-39B/BLaser SDB

Air Force procurement material identifies the GBU-39B/B as the Laser SDB configuration.

Sources: FY22 DAF Missile Procurement Justification Book

Carrier Aircraft

Official Air Force and Boeing sources document the bomb on fighters, gunships, stealth aircraft, and MQ-9 integration; these are the most specific public examples.

CarrierCarrier typeCarriage evidence
F-15 family fighter aircraft, Fighter aircraft family, Aircraft & UAVsF-15 family fighter aircraftStrike fighter

Boeing's Advanced F-15 weapons inventory lists GBU-39 Small Diameter Bomb among the aircraft's external carriage options.

Sources: Advanced F-15 Weapons Inventory

F-15E Strike Eagle, Dual-role strike fighter, Aircraft & UAVsF-15E Strike EagleStrike fighter

The Air Force said F-15E Strike Eagle crews first used the GBU-39 in combat over Iraq in October 2006.

Sources: USAFE unit debuts small diameter bomb in combat

F-22 Raptor, Fifth-generation stealth air-superiority fighter, Aircraft & UAVsF-22 RaptorStealth fighter

Air Force procurement material lists the F-22A among integrated SDB I platforms.

Sources: FY22 DAF Missile Procurement Justification Book

F-16 Fighting Falcon, Multirole fighter aircraft, Aircraft & UAVsF-16 Fighting FalconMultirole fighter

Air Force procurement material lists F-16C/D Block 30/40/50 aircraft among integrated SDB I platforms.

Sources: FY22 DAF Missile Procurement Justification Book

F-35A Lightning II, Conventional takeoff and landing stealth multirole fighter, Aircraft & UAVsF-35A Lightning IIStrike fighter

Air Force procurement material lists the F-35A among integrated SDB I platforms.

Sources: FY22 DAF Missile Procurement Justification Book

AC-130 gunship, Heavily armed fixed-wing gunship, Aircraft & UAVsAC-130 gunshipGunship

Air Force sources list AC-130W/J integration, and AFSOC says the AC-130 can carry up to eight GBU-39B bombs on wing-mounted stations.

Sources: FY22 DAF Missile Procurement Justification Book, AFSOC GBU-39B MQ-9 Service Entry

MQ-9 Reaper, Medium-altitude long-endurance unmanned combat aerial vehicle, Aircraft & UAVsMQ-9 ReaperUnmanned combat aerial vehicle

DVIDS documented GBU-39 loading on an MQ-9 Reaper, and AFSOC said the 27th Special Operations Wing added GBU-39B to MQ-9 operations through the BRU-78 Dual Carriage System in spring 2026.

Sources: DVIDS MQ-9 GBU-39 loading video, AFSOC GBU-39B MQ-9 Service Entry

Compatible Aircraft
Compatible itemItem typeCompatibility evidence
B-2 Spirit, Low-observable strategic heavy bomber, Aircraft & UAVsB-2 SpiritFuture platform

The Air Force said the B-2 Spirit was among future platforms for the GBU-39/B Small Diameter Bomb.

Sources: ACC declares small diameter bomb initially operational

Timeline

GBU-39/B Small Diameter Bomb I Key Events

  1. Development work begins

    Air & Space Forces reports that the Small Diameter Bomb effort began as an Air Combat Command response to the need for a smaller precision weapon with reduced collateral damage.

    Sources: GBU-39 Small Diameter Bomb I

  2. First flight

    The same report says Boeing was selected to develop and produce the weapon in 2003 and that the bomb first flew on May 23, 2003.

    Sources: GBU-39 Small Diameter Bomb I

  3. Low-rate initial production

    Air & Space Forces reports that low-rate initial production began in 2005.

    Sources: GBU-39 Small Diameter Bomb I

  4. Air Combat Command declares IOC

    The Air Force fact sheet says Air Combat Command declared initial operational capability for the GBU-39/B on Oct. 2, 2006.

    Sources: GBU-39B Small Diameter Bomb Weapon System

  5. First combat use

    The Air Force said F-15E Strike Eagles first used the GBU-39 in combat over Iraq on Oct. 5, 2006.

    Sources: USAFE unit debuts small diameter bomb in combat

  6. Afghanistan strike reported

    An Air Force airpower summary said F-15E Strike Eagles dropped GBU-39 Small Diameter Bombs on enemy small-arms positions near Qurya, Afghanistan.

    Sources: Feb. 25 airpower F-16s provide watch

  7. Ukraine air-launched use confirmed

    TWZ reported U.S. confirmation that Ukraine was using the air-launched GBU-39 Small Diameter Bomb in combat.

    Sources: TWZ Ukraine air-launched GBU-39 report

  8. MQ-9 loading event documented

    DVIDS published public-domain video of two GBU-39 Small Diameter Bombs loaded on an MQ-9 Reaper with a Dual Carriage System at Creech Air Force Base.

    Sources: DVIDS MQ-9 GBU-39 loading video

  9. AFSOC reports MQ-9 service entry

    Air Force Special Operations Command reported that 27th Special Operations Wing MQ-9 Reapers at Cannon had added the GBU-39B Small Diameter Bomb Weapon System to their operational arsenal.

    Sources: AFSOC GBU-39B MQ-9 Service Entry

Media

GBU-39/B Small Diameter Bomb I Videos

GBU-39/B Small Diameter Bomb I Images

GBU-39/B Small Diameter Bomb I, 250-pound GPS/INS-guided glide bomb, Munitions - view 1
Source: 201128-Z-OK775-025
GBU-39/B Small Diameter Bomb I, 250-pound GPS/INS-guided glide bomb, Munitions - view 2
Source: 201128-Z-OK775-008
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Related News

Sources

Small Diameter Bomb Product CardPublisher: Boeing | Note: Supports Boeing's official product background, technical specifications, and the F/A-22, F-35, fighter, and bomber compatibility claims. | Accessed: 2026-07-08GBU-39B Small Diameter Bomb Weapon SystemPublisher: U.S. Air Force | Note: Supports GBU-39/B background, Air Combat Command initial operational capability, unit cost, performance, and public-domain image context for the gallery images. | Accessed: 2026-07-08201128-Z-OK775-012Publisher: U.S. Air Force | Note: Supports public-domain image provenance for the primary gallery image of a GBU-39 at Al Udeid Air Base on Nov. 27, 2020. | Accessed: 2026-07-08201128-Z-OK775-025Publisher: U.S. Air Force | Note: Supports public-domain image provenance for the gallery image of a bomb rack unit with four GBU-39 bombs at Al Udeid Air Base on Nov. 27, 2020. | Accessed: 2026-07-08201128-Z-OK775-008Publisher: U.S. Air Force | Note: Supports public-domain image provenance for the gallery image of four GBU-39 bombs in the munitions storage area at Al Udeid Air Base on Nov. 27, 2020. | Accessed: 2026-07-08ACC declares small diameter bomb initially operationalPublisher: U.S. Air Force | Note: Supports B-2 Spirit among future platforms for the GBU-39/B Small Diameter Bomb. | Accessed: 2026-07-08AFSOC AC-130J Ghostrider Fact SheetPublisher: U.S. Air Force Special Operations Command | Note: Supports AC-130J Ghostrider carriage of the GBU-39/B Small Diameter Bomb I in the aircraft's standoff precision-guided munitions loadout. | Accessed: 2026-07-08Air Force AC-130J Ghostrider Fact SheetPublisher: U.S. Air Force | Note: Supports AC-130J Ghostrider carriage of the GBU-39/B Small Diameter Bomb I in the aircraft's standoff precision-guided munitions loadout. | Accessed: 2026-07-08Advanced F-15 Weapons InventoryPublisher: Boeing | Note: Supports F-15 family carriage of GBU-39 Small Diameter Bomb in Boeing's external carriage matrix. | Accessed: 2026-07-08AP Rafah GBU-39 reportPublisher: Associated Press | Note: Supports direct conflict use in the 2023 Israel-Hamas War; AP reported Israeli forces used likely GBU-39 small-diameter bombs in the May 26, 2024 Rafah airstrike. | Accessed: 2026-07-08AC-130W Stinger IIPublisher: U.S. Air Force | Note: Supports 2014 War Against the Islamic State direct conflict use under Operation Inherent Resolve: Supports direct conflict use in 2014 Operation Inherent Resolve; the U.S. Air Force said AC-130W gunships carried GBU-39 bombs as part of the Precision Strike Package. | Accessed: 2026-07-08GBU-39 Small Diameter Bomb IPublisher: Air & Space Forces Magazine | Note: Supports development timeline, first flight, low-rate initial production, BRU-61/A four-bomb carriage, and fighter/bomber compatibility context. | Accessed: 2026-07-08FY22 DAF Missile Procurement Justification BookPublisher: U.S. Air Force | Note: Supports SDB I platform integration details, GBU-39A/B Focused Lethality Munition, and GBU-39B/B Laser SDB variant descriptions. | Accessed: 2026-07-08USAFE unit debuts small diameter bomb in combatPublisher: U.S. Air Force | Note: Supports direct conflict use in the 2003 Iraq War; the Air Force said F-15E Strike Eagles first used the GBU-39 in combat over Iraq in October 2006. | Accessed: 2026-07-08Feb. 25 airpower F-16s provide watchPublisher: U.S. Air Force | Note: Supports direct conflict use in the 2001 War in Afghanistan; the Air Force said F-15E Strike Eagles dropped GBU-39 Small Diameter Bombs during a February 2007 strike near Qurya, Afghanistan. | Accessed: 2026-07-08TWZ Ukraine air-launched GBU-39 reportPublisher: The War Zone | Note: Supports direct conflict use in the 2014 Russia-Ukraine War; TWZ reported U.S. confirmation that Ukraine used air-launched GBU-39 Small Diameter Bombs in combat. | Accessed: 2026-07-08DVIDS MQ-9 GBU-39 loading videoPublisher: Defense Visual Information Distribution Service | Note: Supports MQ-9 Reaper loading and Dual Carriage System integration context for two GBU-39 Small Diameter Bombs at Creech Air Force Base; DVIDS identifies the work as public domain. | Accessed: 2026-07-08AFSOC GBU-39B MQ-9 Service EntryPublisher: Air Force Special Operations Command | Note: Supports GBU-39B service entry on 27th Special Operations Wing MQ-9 Reapers, BRU-78 carriage, Cannon Air Force Base integration context, and AC-130 carriage capacity. | Accessed: 2026-07-08