By The War Zone | Created at 2025-03-14 17:16:08 | Updated at 2025-03-14 21:28:38
4 hours ago
Improved versions of the Ground-Launched Small Diameter Bomb (GLSDB) are reportedly among the weapons that will be sent to Ukraine after the United States decided to resume military aid and intelligence sharing with Kyiv. The GLSDB had made its combat debut in Ukraine, but it reportedly performed poorly there, especially due to the effects of Russian electronic warfare, and was last used “months ago.”
According to the Reuters news agency, which cites two unnamed individuals familiar with the weapon, the next batch of GLSDBs for Ukraine will be “upgraded to better counter Russian jamming.”
The GLSDB is back on the table for Ukraine after President Donald Trump’s administration agreed on Tuesday to restart weapons transfers after Kyiv said it was willing to back a U.S. proposal for a 30-day ceasefire with Russia.
According to the same report, the GLSDB is especially needed to fill the gap after the significant depletion of Ukraine’s stocks of the Army Tactical Missile System (ATACMS). This is a short-range ballistic missile that has had considerably more success on the battlefield.
Few details are available of the upgrades made to the GLSDB, although TWZ has approached the co-manufacturer, Saab, for more information.
The Reuters report states that the modifications to the weapon include “reinforcing connections within the weapon to enhance its resilience.” This seems to suggest that some work was needed to make the weapon better able to withstand the stresses involved in the launch process, during which it’s propelled by a rocket motor.
The report adds that 19 GLSDBs were test-launched in recent weeks to confirm the effectiveness of the upgrades.
Originally developed by Boeing and Saab, the GLSDB is a surface-launched, standoff precision strike weapon based on the air-launched Small Diameter Bomb (SDB).
Each GLSDB round consists of two existing components, the air-launched GBU-39/B SDB and the rocket motor from the 227mm-caliber M26 artillery rocket. The M26 is among the rocket types that can be fired from the M270 Multiple Launch Rocket System (MLRS), and variants thereof, and the M142 High Mobility Artillery Rocket System (HIMARS).
A scale model of a complete GLSDB round. Joseph Trevithick For the initial boost/loft phase, the GLSDB is propelled by the M26 rocket motor, after which pop-out wings are deployed and the munition flies unpowered, as a glide bomb. It uses the GBU-39/B’s existing inertial navigation system and embedded GPS to guide it to its target. The GLSDB has a range of around 94 miles, making it especially relevant to Ukraine as it seeks to target Russian supply lines and muster points.
In the past, Saab has claimed that the GLSDB’s guidance system ensures accuracy to within three feet. Prior to the weapon’s use in Ukraine, the company has also said that the GLSDB is resilient to electronic warfare jamming.
However, reports out of Ukraine suggest that the GLSDB proved vulnerable to Russian countermeasures, something that saw the weapon reportedly discarded by the Ukrainian Armed Forces.
On the other hand, it should be noted that the air-launched SDB appears to have performed very well with the Ukrainian Air Force, making accounts of the GLSDB’s susceptibility to jamming at least somewhat puzzling. The SDB was initially integrated on Soviet-era combat aircraft, with the aid of a specially prepared pylon, and is now part of the armory of Ukrainian Air Force F-16s, too.
GBU-39/B SDBs loaded on a Ukrainian Air Force MiG-29 Fulcrum fighter. via X Once the new GLSDBs reach the battlefield, we may learn more about their particular improvements and the capabilities they bring.
Meanwhile, the development of an improved GLSDB is a logical step, considering the effect that Russian GPS jamming, in particular, has had on the efficiency of Western precision-guided ground and air-launched munitions used by Ukraine. As the conflict has continued, Russian forces have significantly expanded their use of various kinds of electronic warfare capabilities.
At the same time, the broader arguments in favor of the GLSDB remain. The weapon offers significantly greater reach than the longest-range 227mm artillery rockets currently available for the M270 MLRS and the M142 HIMARS.
The GLSDB also offers notable versatility in that it can be fired from a number of different launchers, including the M270 MLRS tracked launcher and the M142 HIMARS, which is based on a wheeled chassis. At this stage, we don’t know what kind of launcher Ukraine was using for its GLSDBs, and its “launcher-independent” nature means it can be fired from other interfaces, too.
An artist’s concept of multiple GLSDBs being used in a simultaneous attack on a hostile mobile missile launcher. Saab A further key advantage is the fact that M26 rockets and the GBU-39/B SDB are widely available in the stockpiles of the United States and other allies.
All of these are of little value, however, if the weapon itself is found wanting once exposed to the realities of combat. Now, it seems, work is well underway to address the issues with GLSDB and Ukraine will hope that this weapon finally fulfills its potential.
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