Ground Launched Small Diameter Bomb Won’t Make Ukraine Combat Debut Till Fall

Recent long-range attacks made by Ukraine – like the one today on the Chongar Bridge in Crimea – have spurred speculation as to what weapons are being employed. One of those that has been promised but has still not been confirmed as operational is the U.S.-donated Ground Launched Small Diameter Bomb (GLSDB), although there certainly has been rumors and claims about its use.

But a top Pentagon official on Thursday testified before Congress that those weapons won’t come online until this Fall. She also said while controversial cluster munitions would “be useful” to Ukraine, the U.S. has no immediate plans to provide them for a host of reasons.

The issue of GLSDBs, a fairly recent adaptation of the GBU-39/B Small Diameter Bombs (SDBs) first promised to Ukraine in February, was brought up by Deputy Assistant Secretary of Defense for Russia, Ukraine, and Eurasia U.S. Department of Defense Laura Cooper Thursday. She was testifying before the House Committee on Foreign Affairs Subcommittee on Europe.

Cooper was responding to a question by Committee Chairman Tom Kean (R-NJ) about why the U.S. has yet to provide Ukraine – having a tough go in its counteroffensive – with Army Tactical Missile System (ATACMS) short-range ballistic missiles. Those weapons can destroy fortified targets about 200 miles away and have been repeatedly requested by Ukraine and its supporters in Congress.

Kean asked Cooper if the Biden administration’s continued denial “of these critical systems to Ukraine” was over concern that such a move would be considered “escalatory in nature” by Russia.

Cooper said her concerns related to “the practical aspects of availability” of the weapons.

As we have previously reported, the Fiscal Year 2023 National Defense Authorization Act called for the production of additional ATACMS.

Cooper has previously noted that when providing weapons to Ukraine, U.S. stocks are taken into consideration. There are a limited number of ATACMS – Lockheed Martin has produced about 4,000 ATACMS in various configurations over the past two decades, according to Politico. Some have been sold to allied nations, which bought the missile for their own multiple rocket launcher systems, while about 600 were fired by U.S. forces in combat. Some of these may have been retired from service or fired in training and testing, as well. ATACMS is seen a critical weapon that would be needed in a peer conflict and until its successor arrives in large numbers, the existing inventory is viewed as strategically important to maintain.

Cooper also noted that there are other options to ATACMS available to Ukraine, the GLSDB among them.

Developed by Boeing in partnership with Saab of Sweden, each GLSDB round is a combination of two existing systems, the air-launched 250-pound GBU-39/B SDB with its pop-out wing set and the rocket motor from the 227mm-caliber M26 artillery rocket. It’s a rocket fired from M270 Multiple Launch Rocket System (MLRS), and its variants, and the M142 High Mobility Artillery Rocket System (HIMARS), both currently in use in Ukraine. It has a range of 94 miles and makes its way to its fixed target via inertial navigation and GPS. You can read more about what the GLSDB would bring to the table for Ukraine in our story here.

“Mr. Chairman, my concerns relate to the practical aspects of availability and also whether there are other systems like Storm Shadow [air-launched cruise missiles], like the Ground Launched Small Diameter Bomb that will come online this fall, other systems including UAVs that can reach the same targets and I will be more than happy to discuss in greater details on these issues in a classified setting,” she said.

Russian officials claim the Storm Shadow, with an officially stated range of at least 155 miles (the non-export configuration is nearly double that) was used in today’s attack on the Chongar Bridge. That, however, has yet to be officially confirmed, but video has emerged that appears to back up the Russian claim.

“We are seeing the effectiveness of the Storm Shadow system provided by the UK and are finding it to be quite effective,” said Cooper when asked about ATACMS.

Cooper was also asked by Kean about the controversial 155mm Dual-Purpose Conventional Improved Munition (DPICM) artillery cluster shells, also sought by Ukraine. Ukraine has also requested the individual stabilized submunitions from cluster bombs to arm its drones, which you can read more about here.

Kean said that “the Russian military has been using cluster munitions with impunity in Ukraine.” He then asked if such weapons “would be helpful to Ukraine’s counteroffensive, particularly in offsetting Russia’s quantitative advantage and manpower armor and artillery.”

Cooper said they would, but the U.S. won’t provide them for several reasons.

“Our military analysts have confirmed that DPICMs would be useful especially against dug-in Russian positions on the battlefield,” Cooper testified. “The reason why you have not seen a move forward in providing this capability relates both to the existing congressional restrictions on the provision of DPICMs and concerns about allied unity. But from a battlefield effectiveness perspective, we do believe that would be useful.”

DPICM shells, each of which disperses 88 submunitions when fired, had been in use with the U.S. military since the 1970s and can be equipped with shaped or fragmentation charges, which are ideal for anti-armor and anti-personnel operations respectively.

Because they fall at a steep angle over a wide area, they can drop into trenches, which would be especially of value to Ukraine as it is forced to fight against Russian troops who have built hundreds of miles of such fortifications.

DPICMS bomblets fall at a steep angle, making them particularly useful against trenches. (DoD chart)

But as Cooper said, there is no indication that the Biden administration will agree to send cluster bombs to Ukraine. These weapons are banned in over 100 countries under the 2008 Convention on Cluster Munitions, not including the U.S., because of the harm they pose to civilians, especially long after they have been launched.

In 2009, President Barack Obama signed off on legislation prohibiting the export of cluster munitions that have a submunition failure rate of 1% or higher, but this can be waived by Biden or any other sitting President. The ban exists because if bomblets in a cluster weapon fail to detonate, dozens of live submunitions would be left scattered around the target area, posing a risk to civilian lives until they could be properly disposed of. This is especially true for curious children. An HRW article from that year states that “only a very tiny fraction of the cluster munitions in the U.S. arsenal meet the one percent standard.”

Kean, the committee chairman, suggested that because Ukraine is seeking to use these weapons on its own soil, that mitigates concerns about the long-term effects.

“The Ukrainians believe that the battlefield benefits outweigh the costs,” said Kean. “And since these would be used on Ukraine’s own territory, Kyiv would be incentivized to judicially limit the post-war threat to civilians.”

But Ukraine has asked for a lot of things, like ATACMS and F-16s.

DPICMs do not appear to be on the table, at least at this time, but that could change.

The Pentagon “has nothing to announce on DPICMs” a U.S. official told The War Zone Thursday.

In the meantime, at least we know that GLSDB’s use in Ukraine still has not occurred, with Fall looking to be its combat debut.

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