GBU-39 Small Diameter Bomb vs LT PGB

People's Liberation Army Air Force^[source]

War in Afghanistan , Iraq War , Military intervention against ISIL , Syrian Civil War , Russian invasion of Ukraine , Gaza war^[source]

Boeing Integrated Defense Systems^[source]

US$40,000 (SDB I, FY 2021)^[source]

2005–present^[source]

2004—present^[source]

17,000+^[source]

GBU-39/B GBU-39A/B GBU-39B/B^[source]

SDB I (GBU-39/B) penetrating blast fragmentation, penetrating steel nosecone SDB FLM (GBU-39A/B) blast ultra-low fragmentation Laser SDB (GBU-39B/B) penetrating blast fragmentation, w/o steel nosecone^[source]

various gravity bombs^[source]

SDB I (GBU-39/B) SDB FLM (GBU-39A/B) GPS / INS Laser SDB (GBU-39B/B) GPS / INS with terminal semi-active laser guidance^[source]

laser guidance^[source]

SDB I (GBU-39) 3 ft (1 m) CEP^[source]

250-pound (110 kg) precision-guided glide bomb^[source]

The GBU-39/B Small Diameter Bomb ( SDB ) is a 250-pound (110 kg) precision-guided glide bomb that is intended to allow aircraft to carry a greater number of smaller, more accurate bombs. Most US Air Force aircraft will be able to carry (using the BRU-61/A rack ) a pack of four SDBs in place of a single 2,000-pound (910 kg) Mark 84 bomb . It first entered service in 2006. The Ground Launched Small Diameter Bomb (GLSDB) was later developed to enable the SDB to be launched from a variety of ground launchers and configurations.^[source]GBU-39 Small Diameter Bomb · Lead; only the objects and conditions stated in this passage

The small size of the bomb allows a strike aircraft to carry more of them than previously available bombs, and thus strike more targets. The SDB carries approximately 36 lb (16 kg) of AFX-757 high explosive . AFX-757 is an insensitive enhanced blast polymer-bonded explosive , containing 25% RDX high explosive, 30% ammonium perchlorate oxidizer, 33% aluminium powder , 4.44% HTPB binder and 6.56% dioctyl adipate plasticizer. AFX-757 has improved air blast equivalent, 1.39 times more than Composition B , but low brisance due to low RDX content. It has integrated "DiamondBack" type wings which deploy after release, increasing the glide time and therefore the maximum range. Its size and accuracy allow for an effective munition with less collateral damage . Warhead penetration is 3 ft (1 m) of steel reinforced concrete under 3 ft (1 m) of earth and the fuze has electronic safe and fire (ESAF) cockpit selectable functions, including air burst and delayed options.^[source]GBU-39 Small Diameter Bomb · Description; only the objects and conditions stated in this passage

The SDB I has a circular error probable (CEP) precision of 3 ft (1 m). CEP is reduced by updating differential GPS offsets prior to weapon release. These offsets are calculated using an SDB Accuracy Support Infrastructure, consisting of three or more GPS receivers at fixed locations transmitting calculated location to a correlation station at the theatre Air Operations Center . The corrections are then transmitted by Link 16 to SDB-equipped aircraft.^[source]GBU-39 Small Diameter Bomb · Description; only the objects and conditions stated in this passage

In January 2016, the Air Force awarded a contract to Scientific Systems Co. Inc. to demonstrate the company's ImageNav technology, a vision-based navigation and precision targeting system that compares a terrain database with the host platform's sensor to make course corrections. ImageNav technology has demonstrated target geo-location and navigation precision within three meters.^[source]GBU-39 Small Diameter Bomb · Description / Alternative guidance and warheads; only the objects and conditions stated in this passage

Under a contract awarded in September 2006, Boeing developed a version of the SDB I that replaces the steel casing with a lightweight composite casing and the warhead with a focused-blast explosive such as dense inert metal explosive (DIME). This should further reduce collateral damage when using the weapon for pinpoint strikes in urban areas. The USAF intends to use the same FLM casing on a weapon of 500 pounds (227 kg). Boeing celebrated the delivery of the first 50 FLM weapons on 28 February 2008 and delivered the last of the 500 FLMs under contract in December 2013.^[source]GBU-39 Small Diameter Bomb · Variants / GBU-39A/B – SDB Focused Lethality Munition (FLM); only the objects and conditions stated in this passage

In 2011 Boeing began testing on a laser-guided version of the baseline SDB, integrating the same Semi Active Laser (SAL) from the GBU-54 Laser JDAM. Boeing claimed to have successfully hit targets moving at 30 mph (48.3 km/h) and 50 mph (80.5 km/h).^[source]GBU-39 Small Diameter Bomb · Variants / GBU-39B/B – Laser SDB; only the objects and conditions stated in this passage

In August 2024, CNN reported that Israel used the GBU/39 again in the Al-Tabaeen school attack , killing over 90 people according to the Gaza Civil Defense. The IDF stated that it was a precision strike against a Hamas command and control center that killed at least 19 Hamas and PIJ militants.^[source]GBU-39 Small Diameter Bomb · Operational history; only the objects and conditions stated in this passage

LT-2 was the first bomb in the LT series, which was renamed from the LS-500J guided bomb. The LT-2 is a strap-on bomb kit that can be mounted on any 500 kg (1,100 lb) class general-purpose bomb . The seeker is an annular airfoil seeker with a quadrant detection assembly similar to that of Paveway I and II. The tail kit is in a similar configuration to the Paveway I. The guidance system is unstabilized in roll, relying on bang–bang control like the Paveway II, and the cruciform tail assembly provides maneuverability.^[source]LT PGB · Development / LT series; only the objects and conditions stated in this passage

LT-3 is a sophisticated upgrade of LT-2. The LT-3 has a dual-mode seeker, combining a satellite / inertial guidance tail kit with a gimbaled laser guidance module. Weighing 564 kg (1,243 lb) and ranging 24 km (13 nmi), the warhead can penetrate 1.5 meters thick reinforced concrete . The mounting bracket and tail structure of the LT-3 is derived from the LS-6 250kg version, though the two bombs have different guidance methods and masses. The concept of the LT-3 is very close to the Paveway III or GBU-55 Laser JDAM . According to the Industry Corporation of China (AVIC) representative at Zhuhai Airshow 2008, the upgrade was substantial. The LT-3 uses a wide field-of-view (FOV) laser beam-riding gimbal, similar to Paveway III. In contrast, the older LT-2 relies on the bang–bang control system that was common in the 1960s on bombs such as Paveway I.^[source]LT PGB · Development / LT series; only the objects and conditions stated in this passage

In the 1990s, multiple targeting pods were developed for the laser-guided bombs. One of the earliest types was called Blue Sky ( Chinese : 蓝天 ; pinyin : Lán tiān ), and was publicly revealed in the late 1990s. The Blue Sky targeting pod is externally similar to the American LANTIRN . The targeting range for LT-2 is 15 km (8.1 nmi). Alternatively, LT PGB can be guided by forward-looking targeting pods, such as FILAT .^[source]LT PGB · Targeting pod; only the objects and conditions stated in this passage

LT-2 : Laser-guided 500 kg (1,100 lb) bombs, originally called LS-500J. In PLAAF service, LS-500J (LT-2) is designated K/YGB500.

Impact / Proximity^[source]

aerial platforms^[source]

• Reported operator · Australia
• Reported operator · Israel
• Reported operator · Italy
• Reported operator · Netherlands
• Reported operator · Saudi Arabia
• Reported operator · South Korea
• Reported operator · Sweden
• Reported operator · Ukraine
• Reported operator · United States